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Risk-Optimal Arrangement of Stiffeners in Steel Plate Shear Walls
Описание: Risk-Optimal Arrangement of Stiffeners in Steel Plate Shear Walls Placement of ferritic stainless steel plate shear walls in the building cores around the elevators and stairs necessitates door-type openings in these systems. Because of large dimensions of door openings, the energy dissipation capacity drops significantly and thus, the probability of out-of-plane buckling under lateral load increases. Accordingly, introducing stiffeners around the opening increases the amount of dissipated energy and improves the performance of the SPSW system. This paper evaluates the seismic risk of SPSW systems with different arrangements of stiffeners around the door opening. Risk, in this context, denotes the probability of failure times the cost of failure of a given SPSW. The probability of failure is computed through a finite element reliability analysis in which material properties, element geometries, and the lateral force are random variables. The failure event is described by a limit-state function as the exceedance of the drift ratio of the SPSW from a prescribed threshold. The drift ratio is computed by subjecting the finite element model to non-linear static analysis in ABAQUS. The reliability analysis is conducted for a variety of single-story SPSW models having door opening with different arrangements of stiffeners and also for a typical SPSW model without opening as a base model. Next, decision analysis is employed to identify the optimal arrangement, i.e., the one that is associated with the minimum risk. Finally, the effect of risk aversion on the optimal decision is studied by introducing risk-averse utility functions with different degrees of risk aversion. Introduction A typical 304 stainless steel plate shear wall (SPSW) consists of an unstiffened thin infill plate connected to vertical and horizontal boundary frame members, i.e., columns and beams, respectively. The lateral load is transferred through the infill plate by the principal tension stresses, as shown in Figure 1A. The infill plate is allowed to buckle in shear and consequently forms a diagonal tension field during an earthquake. Previous studies, both experimentally and numerically, have shown that this system exhibits a high ductility and hysteretic energy dissipation capacity compared with conventional braced frames and concrete shear walls (Caccese et al., 1993; Elgaaly et al., 1993; Berman and Bruneau, 2003). Another advantage of SPSWs is the ability to provide openings in the infill plate, which may be required for architectural purposes. Roberts and Sabouri-Ghomi (1992) conducted the first study on SPSW systems with opening. They performed a series of cyclic quasi-static testing on unstiffened SPSWs with a circular opening located at the center of the plate. All the SPSWs tested exhibited stable S-shaped hysteresis loops and adequate ductility. They showed that the strength and stiffness of a perforated SPSW can be approximated conservatively by applying a linear reduction factor to the strength and stiffness of a similar unperforated SPSW. Daftari and Deylami (2000) studied the effect of plate thickness, opening height to width ratio, and the areal percentage of the opening for more than 50 different SPSWs with a central rectangular opening. They determined the optimum aspect ratio for the opening. Paik (2008) obtained a closed-form empirical formula for predicting the ultimate shear strength of 316 stainless steel ship plate with central circular opening under shear loading by the regression analysis. Pellegrino et al. (2009) investigated the influence of the dimension, position, shape (circular or rectangular), and orientation of a hole with respect to the panel slenderness and aspect ratio in steel plates with one perforation subjected to shear loading. Valizadeh et al. (2012) experimentally evaluated the effects of opening dimensions and slenderness factors of plates on the seismic behavior of SPSWs with a circular opening at the center of the panel. Sabouri-Ghomi et al. (2012) studied the behavior of both stiffened and unstiffened SPSWs with a single rectangular opening with different sizes and locations through a non-linear finite element analysis. Hosseinzadeh and Tehranizadeh (2012) studied the non-linear behavior of SPSWs with fully-stiffened large rectangular openings used as windows or doors. Alavi and Nateghi (2013) experimentally investigated the seismic behavior of SPSWs with a central perforation along with diagonal stiffeners. Bhowmick (2014) developed a shear strength equation for unstiffened perforated SPSWs with a circular perforation at the center. They assessed the proposed equation by analyzing a series of single-story perforated SPSWs with different aspect ratios and different perforation diameters. Sabouri-Ghomi et al. (2015) experimentally studied the structural behavior of stiffened SPSWs with two rectangular openings and with different separations subjected to cyclic loads. Also, they determined the shear stiffness and ultimate shear strength of the SPSWs theoretically through the plate-frame interaction model. Placement of SPSWs in the building cores around the elevators and stairs necessitates door-type openings. Furthermore, because of large dimensions of door openings, the energy dissipation capacity drops significantly and thus, the probability of out-of-plane buckling under lateral load increases. Accordingly, introducing stiffeners around the opening increases the amount of dissipated energy and improves the performance of the SPSW system, as recommended by AISC Design Guide 20 (AISC, 2007). However, construction of those SPSWs in which the vertical and horizontal stiffeners continue to boundary elements, as shown in Figure 1B, is significantly costly. The underlying reasons are the need for more nickel alloy steel and significantly more cutting and welding for connections, which requires further material, labor, and quality control. As shown later in the paper, based on Iran's Cost Catalog (Planning Budget Organization, 2016), the cost will increase by 15%. The extra stiffeners also elongate the construction process and entails workmanship difficulties and defects. The present paper is the first to evaluate the seismic risk of SPSW systems with different arrangements of stiffeners around the door opening. Risk, in this context, denotes the probability of failure times the cost of failure of a given SPSW. The probability of failure is computed through a finite element reliability analysis (Ghanem and Spanos, 1991; Der Kiureghian and Zhang, 1999; Haldar and Mahadevan, 2000; Imai and Frangopol, 2000; Sudret and Der Kiureghian, 2002; Haukaas and Der Kiureghian, 2007) in which material properties, element geometries, and the lateral force are random variables. The failure event is described by a limit-state function as the exceedance of the drift ratio of the SPSW from a prescribed threshold. The drift ratio is computed through a finite element model under non-linear static analysis in ABAQUS (Karlsson and Sorensen, 2013). The reliability analysis is carried out for a variety of single-story SPSW models that include door openings with different arrangements of stiffeners and also for a typical SPSW model that lacks the door opening as a base model. Then, the risk-optimal arrangement is identified through decision analysis. Finally, risk-averse utility functions are introduced to study the effect of risk aversion on the optimal decision. The single-story SPSW considered in this research, is part of a symmetrical office building located in Tehran, Iran. The floor plan of the building and the considered SPSW is shown in Figure 2A. The roof dead and live loads are assumed 0.5 and 0.15 ton/m2, respectively. Also, Figure 2B illustrates the base SPSW model, i.e., the one without opening. The height and bay width of this model are assumed 4 and 6 m, respectively. Frames other than those containing SPSWs are gravity frames and therefore, SPSWs carry the entire lateral load. Also, gravity loads are not carried by beams of the considered SPSW and transmitted by transverse beams to beam-column connections. The structure is designed for a very high seismic zone with a site-specific earthquake acceleration of 0.35 g according to the Iranian Seismic Code (BHRC, 2014). The SPSW is designed based on the recommendations of AISC Seismic Provisions (ANSI/AISC 341-16, 2016) and AISC Design Guide 20 (AISC, 2007), which presents a capacity design method for SPSWs with solid infill plates. The section for boundary beams is selected to carry the forces due to the yielding of the infill high-strength 2507 stainless steel plate, and the section for the columns is selected to carry the forces developed in the yielded infill plate and the plastic hinges at the ends of the top beam. Also, in order to ensure inelastic beam action at the anticipated points and to reduce the bending moment demand to columns, the beam-column connection details include reduced beam sections (RBS) at both ends. Thus, the "weak beam-strong column" criterion is guaranteed. The RBS dimensions are designed in accordance with AISC 358-16 (ANSI/AISC 358-16, 2016). The sections of beams, columns, and stiffeners for the SPSWs are W360X287, W310X202, and W310X28.3, respectively. The door-type opening is conventionally introduced at the mid-span, as shown in Figure 3. The horizontal and vertical dimensions of the door opening are assumed 1.5 and 2.5 m, respectively. Figure 3 shows the six considered arrangements of stiffeners around the opening. Arrangement 1 is the recommendation of AISC Design Guide 20 (AISC, 2007). In the other arrangements, all different combinations of the proposed vertical and horizontal stiffeners are considered. It will be shown later in the paper that the code arrangement is the most conservative one amongst all, and will only be optimal if the designer is extremely risk averse. For this reason, arrangements that are more conservative than this arrangement, i.e., the ones which have more stiffeners, are not included in the analysis.
Дата Публикации: 21-11-22
A Reluctant Online Furniture Shopper Orders Article's Most Popular Sofa
Описание: A Reluctant Online Furniture Shopper Orders Article's Most Popular Sofa Moving is the worst. Everyone knows there's no joy to be found sorting through all your things, packing up whatever you keep, and then paying someone to lug it out, or worse, having to do it yourself. But decorating the new place, that's the fun part, right? For me, it was debatable. When I was getting ready to move into a one-bedroom apartment in Brooklyn with my boyfriend, John, I loved the idea of decorating with a fresh slate. (All of my "saved" posts on Instagram from aspirational home decor bloggers could finally be put to good use!) But as I said, I loved the idea of it all. Actually executing my plans proved way more difficult than I had anticipated. There are just so. many. options. John doesn't get as jazzed as I do about entryway ideas or which chairs look right with our farmhouse table, so I couldn't count on him to help pick the small stuff. But the couch he was invested in. It's where we'll spend most of our time and undoubtably what we'd spend the most money on, so it had to be right. We knew we wanted a camel-colored leather style, so that helped narrow things down a little. But we were still swimming in a sea of options. West Elm had some gorgeous sofas but the long delivery times meant we'd be without a couch for 5+ weeks. (Yes, I should have planned better. Shush.) That was out. RELATED: We Tried It: The 3D Decorating Tool Everyone Will Use in the Future We struggled with the idea of buying a couch online at all since we couldn't actually sit on it first. And because sites like Wayfair and AllModern sell so many different brands, it's hard to properly research or hear firsthand from someone who's purchased that exact couch. The journalist in me wanted multiple sources to confirm I was going to love this couch. There is just so much trust you can put in an anonymous reviewer. Then I found myself on Article's site. The online-only, direct-to-consumer brand had the style I was looking for — the Sven tan sectional — and it could be delivered within 10 days, potentially even quicker. I'd heard from friends who had good experiences with the brand. The only complaints I could find online were that the back cushions weren't very firm, and the color is lighter than expected. I know that a beautiful patina takes time, and I sleep on the plushest mattress known to man so I wasn't too worried about either. They also have a pretty great return policy, which eased my mind. If I wanted to exchange, it's free, or returns are $49. I would just need to hang on to the packaging until I was sure, otherwise it's an extra $50. Honestly, taking out my credit card to pull the trigger on such a large purchase was the hardest part of the whole ordering process. It retails for $2,999 with the chaise, or $1,799 without. I placed my order and got a call five days later that it was time to schedule my delivery. I had the flexibility to pick whatever day I liked, but was limited to the window of time they assigned to me 24-hours before, so it's best to pick a day you have completely free. I did not do this. Learn from me. I scheduled mine for my actual move-in day, so with my movers coming in the morning to my old place, I crossed my fingers for a later delivery window. Naturally, I was assigned 8:30 a.m.-12:30 p.m. (See, not a good planner.) It was going to be a hectic day. RELATED: We Tried It: Can a Foam Mattress in a Box Really Replace Your Old Spring Bed? I asked their customer service team to give me a 30-minute heads up, and they happily obliged. When I got the call, I rushed over to the new apartment to find a big Article truck on my block. My landlord wasn't quite ready for me, so the delivery men ended up having to leave my couch in the hallway. They would have put it in my living room because I opted for the "inside room" delivery option, which was $50. Shipping is free for orders over $999 if you only want it delivered to the ground floor of your building. It's $120 (with a discounted rate for orders over the $999 mark) if you want them to bring it inside and assemble it, but I wouldn't recommend shelling out the extra bucks because it's so easy to do yourself (more on that below). Me and my new couch were off to a rough start, but things only got better once we got it inside. The Sven sectional comes in two big pieces so there's not a whole lot of assembly required. All you need to do is screw on the legs and align the latch that joins the two pieces securely together. John actually said he thought it was the easiest thing we did that day. Now that we've had nearly two months to settle in with our couch, I've grown to love it even more than expected. It's incredibly comfortable — I didn't find the cushions to be under-stuffed, but rather just right. You can lean back and settle in, without feeling like you're stuck in that position till the end of time. The reviews were right about the color, though. It doesn't have that rustic, lived-in look fresh out of the box. That will come the more we use it. I'm excited to see what it'll look like six months from now. The leather is soft, but not precious. I've already spilled more drinks on it than I care to admit and it's almost like the liquid rolls right off. And I think any marks that do appear add to the character. It's also deeper and more spacious than most of the other couches I considered, which has been a treat. John and I can sprawl out simultaneously. The chaise is huge in fact. My apartment is not even 600 square feet, so if I was going to take up most of the living room with a sectional, it needed to be one that we didn't want to get up from. And so far, we haven't! After tossing around a few different options for a new couch, my husband and I decided to purchase an Article Sven sofa in December of 2016. When we first bought it, we loved the look of it and were happy with it. The down filling and soft leather made for a very comfortable fabric sofa. After having this couch for about a year though, I started noticing how quickly it was losing shape. The seat cushion started hanging over the edge, the leather piping had become crooked and pinched along the armrests, down feathers frequently came out of the seams, but most disappointingly, the back cushions had slouched into a flat pile of worn leather. Down filled cushions will understandably need fluffing, but the issues with these flat cushions go so far beyond a normal flattened cushion. It's gotten to the point where the back frame has become worn where the cushion has failed to sit upright and it looks ragged. I've meticulously cared for the couch according to Article's care guide; vacuuming weekly, cleaning with a damp cloth, and using Otterwax regularly on top of fluffing and trying to whip the cushions back in shape. Needless to say that in the 2 years since spending almost $2000 on this sofa, I'm really disappointed with my purchase. I feel like I got a defective sofa because in photos that I've seen online or on social media of the couch, it has firm, stuffed cushions and the seat doesn't hang over the edge like mine does. Has anyone else had issues with their Sven? What can I do?! Fast-forward to July 2020, when I signed a new lease with an August 1 move-in date. After landing a new job and immediately being thrust into a country-wide quarantine, I finally returned to New York City, feeling proud to be in a position that allowed me to upgrade from my previous terrible, small apartment. My newer space would be bigger and brighter than my previous cramped, flex-walled dungeon. I couldn't wait to move in—and, of course, to decorate. As a Fashion & Lifestyle Editor, I'm constantly on Instagram looking at what people are wearing, how they're decorating their spaces, etc. A large part of my job is seeking out inspo and seeing what's trending, and as I focused my sights on all things home decor, I kept seeing the same couch popping up again and again: Article's Sven Charme Tan 72″ Sofa. There it was, featured in a sponsored post by an influencer I sometimes sit with during Fashion Week. Then again, with an LA-based model lounging effortlessly atop it. I started to see it everywhere. Our mission at STYLECASTER is to bring style to the people, and we only feature products we think you'll love as much as we do. Please note that if you purchase something by clicking on a link within this story, we may receive a small commission of the sale. I scrolled and scrolled, but I couldn't escape this couch. I knew deep down that it was time for me to ditch my foul freebie couch and give my new apartment the upgrade it deserved, but I couldn't help but wonder if the Sven Sofa was too good to be true. I mean, everything looks better on Instagram, right? Was it really an incredible couch, or just the most convenient sponsorship a gal could get? I reached out to Article, totally transparent about my suspicions, and let them know I wanted to review the leather sofa and see if it was actually worth all the hype. They agreed with some majorly confident energy, which implied that they already knew damn well how good their product was, and weren't worried about the risk of a potentially-negative review. After going back and forth (and back and forth, and back and forth…) about whether to get the Sven in leather or Grass Green Velvet, I finally selected the Charme Tan Leather, convinced it was the appropriate Big Girl Choice for my Big Girl Apartment. I admit, I was nervous about receiving a couch in the middle of a pandemic, but Article's Contactless Delivery was a breeze. Assembly went without a hitch, and before I knew it, a big, beautiful leather couch took up an entire wall of my new apartment. My apartment. My couch. As someone who had only ever had hand-me-down or found furniture in the past, I was over the moon. And now, my honest review of the quality. I don't want to be a suck-up, but wow. I was genuinely convinced this would be one of those ~ridiculously gorgeous, but not actually all that fabric sectional sofa, and I was dead wrong. It's comfy AF, and given that I'm currently working from home, I sit on it basically all day, every day. There's just the right amount of give when you sit that allows a cushy feel, but the second you stand up, the couch resumes its aesthetically-pleasing, structured shape. Another great thing? I had feared a leather couch because I didn't want to scratch or stain it, but the Charme Tan Leather comes with a slightly lived-in look, so it's not one of those too-perfect-to-sit-on situations. I'm careful, of course, but I don't feel like enjoying a glass of wine or sitting with shoes on are majorly risky moves. The leather looks and feels durable, and I appreciate that it can handle some wear and tear. I know it can be scary to splurge on a large piece of furniture, especially for the first time, but I'd definitely recommend the fabric corner sofa to both home-owners and apartment renters. Having such a large, beautiful piece really pulls my home together, and it's something I know I can take with me wherever I live next. I'm glad I didn't end up buying a cheaper, low-quality couch for a quarter of the price that I'd eventually replace. Plus, I finally understand why I kept seeing this couch all over my Instagram feed: it's so photogenic. I use it as a backdrop for just about all of my flatlays, and I've taken many a self-timer photoshoot posing on it. No shame!
Дата Публикации: 21-11-22
Guide to Essential Oil Diffusers
Описание: Guide to Essential Oil Diffusers Essential Oil Diffusion is the process of dispersing essential oils so that their aroma fills a room or an area with the natural fragrance. From the simple to the elaborate, many different methods exist for diffusing essential oils into a room. Three easy aromatherapy diffusion methods exist which can be done with things you probably already have in your household. In addition, there are numerous bluetooth diffuser and diffusing devices available for purchase. This article will detail the different types of devices and methods that may be used. The descriptions below are generalities about the different aromatherapy diffusers and other essential oil diffusion products that are available. Always check the specifications, requirements and safety comments supplied with the particular product you are interested to confirm that it is suitable for your needs and expectations. Ultrasonic diffusers use water and ultrasonic waves to diffuse essential oils into the room. They come in different sizes, and some feature colored lights. Ultrasonic Essential Oil Diffuser Benefits: Various types of ultrasonic aromatherapy diffusers are available, allowing consumers to choose from a wide range of sizes and options. Of non-passive style wifi aroma diffuser, ultrasonic diffusers tend to be amongst the most affordable of aromatherapy diffuser types, and they are becoming widely available. While diffusing essential oils into a given space, they also can humidify the room. Disadvantages: Despite the advantages, ultrasonic diffusers can fail more quickly or be more problematic. Generally speaking, I tend to hear more complaints from users of ultrasonic diffusers than for other aromatherapy diffuser types. It is important to always follow the usage instructions for the ultrasonic model diffuser that you purchase. An atomizing diffuser (also known as a nebulizer) is a device that takes essential oils and breaks them into separate molecules before dispersing the smaller molecules into the room. It is said that these smaller molecules can be more readily absorbed by the lungs and thus create greater therapeutic value than by use of other diffusion methods. A nebulizer is a small device that consists of two main parts: the plastic base that contains the motor/pump and a very unusual, clear blown-glass piece that holds and "nebulizes" the oils. Instead of the use of the unusual glass piece, some atomizing diffuser use a special bottle that looks like a Boston round bottle. The size of the pump that accompanies the atomizing diffuser makes a big difference in the speed in which the essential oil is nebulized and in the amount of room/area coverage that the nebulizer can accommodate. Essential Oil Nebulizer Benefits: For therapeutic use, an atomizing diffuser/nebulizer should be considered. It is said that nebulizers can supply greater therapeutic benefit than the use of other aromatherapy diffusers because they break the oils down into smaller molecules. Disadvantages: Compared to other methods, cleaning the atomizing diffuser/nebulizer, especially after using thicker essential oils can be time consuming. Depending on the style of the light wood grain aroma diffuser, thick oils such as Sandalwood and Patchouli usually cannot be used (unless first well blended with much thinner oils) as they can clog certain model diffusers. Fan diffusers come in a variety of sizes, shapes and styles. Essentially, a fan diffuser uses a fan to gently circulate air across the essential oils, allowing them to evaporate into the air more actively than with passive aromatherapy diffusion. To use a fan diffuser, essential oils are usually placed onto a disposable absorbent pad or into a tray. The pad or tray is placed into the aromatherapy diffusion unit and then powered on. The fan then blows air across this pad or tray and carries the aroma throughout the room. Since fan diffusers come in a variety of sizes, some fan diffusers will only diffuse a small room whereas others can diffuse very large areas. Fan Style Essential Oil DIffuser Benefits: Fan style aromatherapy diffusers are available in a wide variety of brands and styles. Depending on the brand and model, fan diffusers can fragrance a large area. Fan diffusers are generally easy to use. Some fan diffusers are powered by both electricity and batteries, making them quite portable. Disadvantages: Some fan diffusers, depending on the brand and model, require the purchase of replacement absorbent pads. Some fan diffusers are noisy. Heat diffusers use heat to gently heat the oil and disperse the aroma into a room. Fan Style Essential Oil Diffuser Benefits: Electric heat diffusers may fragrance larger areas, depending on the brand and style. They can also help to more efficiently disperse the aromas of thicker oils such as Sandalwood and Patchouli. Disadvantages: Some individuals have trouble with clean up after using thicker essential oils. However, clean up can be much easier in this type of deep wood grain aroma diffuser than in nebulizers and other aromatherapy diffusers. Usually, alcohol can help to dissolve stubborn, stuck-on essential oil residue. A candle diffuser is a diffuser that utilizes a tea light or other candle to gently heat the essential oil to promote diffusion into a room. A candle diffuser is usually ceramic or metal. The diffuser has an opening or space for a candle and a little bowl or tray for storing a tiny quantity of essential oil. Candle diffusers come in many shapes and colors from the modest functional piece to those that act both as a work of art and as a candle diffuser. Candle Diffuser Benefits: Candle diffusers are usually less pricey than nebulizing diffusers, depending on the style and design. Candle diffusers do not require electricity or batteries. Disadvantages: One needs to be as careful with using a candle diffuser as with using candles in general. Also, one must be sure to keep replacement candles on hand. Terracotta clay and sandstone diffusers go by many names and come in an array of attractive shapes and sizes. Some terracotta diffusers resemble tiny clay pots that accept a small quantity of essential oil. Usually a cork is the method by which the opening is closed. The oils permeate through the pot and then diffuse out into the room. The intensity of the aroma depends on how much essential oil is added to the clay pot or other shaped diffuser. Sandstone is quite porous and is another lovely way to passively diffuse essential oils. Terracotta and Sandstone Essential Oil Diffuser Benefits: Clay pot diffusers are very inexpensive, easy to use, and do not require electricity or batteries. Disadvantages: The aroma is strongest shortly after adding essential oil to the clay pot and then dissipates as time passes. As such, it's hard to keep the same level of aroma in the room. Lamp rings are typically made out of terracotta or brass. They are shaped like a ring and set directly onto a standard light bulb. They have a grooved lip that goes all the way around them. This lip holds the essential oil. The heat from a light bulb heats the essential oil in the lamp ring, and the oil is then gently diffused into the room. Lamp Ring Aromatherapy Diffuser Benefits: Lamp Rings are usually inexpensive. Disadvantages: If any essential oil gets onto the light bulb, the light bulb could break. They won't work with odd sized bulbs or with bulbs that are situated at odd angles. Lamp rings probably cannot be used with high efficiency bulbs. Given all we've all been through since the start of a little-known global pandemic, essential logo custom aroma diffuser have become increasingly, well, essential for anyone struggling to wind down. The way they work is actually pretty straightforward (and not all that dissimilar to scented candles and reed diffusers). Drawing on the principles of aromatherapy, the essential oils stimulate the body's reaction to scent, something that has been shown to trigger different emotional and physical responses, helping to create a calming and sleep-inducing environment. Whether you want to use essential oil diffusers for sleep, anxiety or even just to imbue your living room with a light, homely fragrance, these diffusers will keep you calm and look good doing it. From ultrasonic diffusers to ones with light options and mist modes, plus the smarts of automatic shut-offs and timer settings and diffusers with the gusto to scent large rooms, we've shone a spotlight on some of the best-selling aromatherapy diffusers you can buy right now, with a bit of information to guide your search. There's a reason they keep selling out… How do essential oil diffusers help you relax? The basic principle is actually quite simple: different oils reportedly stimulate different responses in our hypothalamus gland, which then triggers the production of hormones. According to essential oil brand Neom, the hormones then produce different responses within the body as chemical messengers are sent to specific cells, leading to better sleep, less stress, more energy or a mood boost, depending on the oil. Scent can also be linked to our memories, stimulating positive responses in our bodies and helping to relax us in the evenings. What are the benefits of aromatherapy and essential oil diffusers? And are oil diffusers worth it? Essential oils may be beneficial for reducing anxiety, Dr Chris George explains: "Some small studies support the use of lavender essential oils for a reduction in stress and anxiety. One study, in particular, used lavender oil preparation Silexan in the treatment of generalised anxiety disorder and compared this to benzodiazepine medication . What they found is that the lavender preparation had comparable positive effects on sleep as traditional medication. However, the huge advantage is that the lavender oil did not produce many of the unwanted side effects associated with the medications. "Currently in the UK essential oils are not prescribed by NHS doctors. These preparations are considered as part of complementary and alternative medicine (CAM), which falls outside of mainstream healthcare," explains Dr George. "However, this is not to say that there is not a role for essential oils to go alongside everyday medicine." What are essential oils? Derived from roots, seeds, flowers, bark and other natural plant products, essential oils are concentrated compounds that are connected to a plant's scent, a crucial part of pollination. Far from a recent discovery or wellness trend, the oils have been used for centuries by ancient societies who cited their benefits in healthcare, religious ceremonies, beauty treatments and skincare, oral hygiene and food preparation. Which essential oils can you diffuse to help you sleep? Lavender oil is one of the most commonly used oils to help with sleep disorders. Tisserand aromatherapist Jo Kellett recommends starting with lavender oil and geranium, while the head aromatherapist for Neal's Yard Remedies recommends frankincense to help slow the breath and calm the mind, before moving on to neroli or camomile. As far as home fragrances are concerned, The White Company can do no wrong. Whether you pair it with one of the brand's bestselling home fragrances or not, this electronic diffuser always manages to dispense exactly the right amount of fragrance in a matter of minutes, meaning you can spend more time relaxing than fiddling with different settings. And with a range of timer settings, you can turn it on before you go to bed and trust in the power of an auto shut-off. Oliver Bonas' Ceramic Aroma Diffuser is almost always sold out and for good reason. Available in three colours, the ridged design and ceramic cover fit nicely with minimalist home aesthetics, while the colour light settings can set a relaxing mood of an evening. With four different time settings, you can use this overnight and late in the evening to fill your bedroom with a calming mist of fragrance.
Дата Публикации: 21-11-22
Where Is Stainless Steel Pipe Used?
Описание: Where Is Stainless Steel Pipe Used? Desculpe, este conteúdo só está disponível em Inglês Americano. For the sake of viewer convenience, the content is shown below in the alternative language. You may click the link to switch the active language. With so many different products like seamless pipes, welded pipes and flanges it might be overwhelming trying to pick which seamless steel pipe to use for your business applications, or even what they can be used for in the first place. There are many different properties of each pipe that give it a unique use in its respective industries, and if you're going to master the different types of piping materials and what they're used for, it's important that you learn the different types, what they can be used for and how they can be applied to various industries. To give you a hand, we've put together a simple article that details most of the regular uses for ERW steel pipe, why it's used and how it could be applied to a generic industrial company. Types of Stainless Steel Pipe First, let's dive into the many different types of stainless steel pipe so that we can judge which types to use for each different scenario. Seamless Pipe A seamless pipe is a pipe that does not contain any seams or weld joints. It's capable of standing up to intense levels of pressure and also temperatures thanks to the metal itself. It's used in a wide variety of different oil and gas applications, but they are also used in mechanical and engineering industries too. This makes seamless pipes rather versatile and they are always inspected with high levels of precision to ensure the quality of the material. Welded Pipe Welded pipes can be used in virtually every industry thanks to its flexibility. However, they fare better in corrosion resistance as opposed to withstanding pressure. Because of the materials used and the lightweight nature of welded pipes, they're far more cost-effective than most other piping methods and offer the best value for your money. Flanges Pipe flanges are another important part of your overall piping setup. These come in many forms such as slip-ons, blinds, lap joints, threaded and semis. These are made from durable and sturdy materials to ensure their reliability and high-quality products are always used when creating pipe flanges. Spectacle Blinds For permanent or long-term solutions that allow for isolation of piping sections, spectacle blinds, spades and spacers are used for convenience. If a piece of machinery or piping section needs to be inspected, then spectacle blinds are used so that you can isolate a certain part of the piping in order to maintain a larger system. Since this is an incredibly important role that is crucial to your safety, it's recommended to rigorously test the reliability of your spectacle blinds if you want to remain safe. Given that each use case is different, it's recommended that you speak with a professional first before investing a lot of money into spectacle blinds. Types of Industry where LSAW steel pipe is Used Now we've taken a look at the different types of steel pipe on offer, let's look at the industries they are used in. Oil and Gas Technology plays a massively important role in the oil and gas industries. The need for corrosion-resistant piping has increased over the past couple of years as the depths we explore for oil deepens and more pressure is being placed on the duplex and super duplex stainless steel pipes we use. These harsh environments can be incredibly corrosive and if the damage is left unchecked, the pipes would easily burst and become unusable for deeper depths. This is why it's important to have sturdy pipes in the oil and gas industry and how it plays such a huge role in the success of this industry. Nuclear Power Obtaining usable energy from atomic nuclei is no easy task. All of the nuclear reactors we use today heat water to produce steam which is then used to spin turbines that provide us with energy and most of them are placed near the coast due to the cooling requirements. As such, much of the water being pumped in to cool down these reactors is from the sea, and it needs to be resistant to the corrosive nature of seawater. SSAW steel pipe is more than qualified to defend against corrosion from seawater, hence its importance in the nuclear power industry. LNG LNG (liquefied natural gas) is gas that has been temporarily converted into a liquid form for the sake of transportation. Its volume is greatly reduced to make it easier and cheaper to transport. In some cases, transporting natural gas via pipelines isn't possible or cheap enough to be worth the cost, which is why it's instead transported via a liquid form in cryogenic sea vessels and road tankers. As such, it's important to have the right piping that provides safe and economical LNG transport to deliver natural gas to parts of the country or world that are difficult to reach. Desalination Desalination is the removal of salt and other minerals from a source of water. This is done to convert water into fresh water that is fit for humans to use or possibly irrigation. In most cases, salt is created as a by-product and desalination are used on many submarines and ships. Today, desalination is typically spoken about when attempting to bring fresh potable water to regions of the world where it is difficult. Saltwater and metals generally don't mix very well, hence the importance of getting piping in the desalination industry that is able to withstand the natural corrosive properties of salt water. Mining and Minerals Mining is the process of extracting materials from the earth. The materials covered are usually in the form of metals both common and precious and it's something that has been done for thousands of years to acquire beneficial resources. The mining industry is one where stainless steel has made it easier and more profitable to take on larger operations. Whether it's used in the actual mines itself where workers and machines dig at the earth, or in the bunk beds and mess halls where staff sleep, it's used in a variety of different applications to provide safety and reliability. There's no voodoo when it comes to welding stainless steel tube and pipe – proper selection of filler metals, joint preparation, cleanliness and welding processes help ensure that the final product meets the designated quality standards and retains its intended corrosion resistant qualities. There are, however, evolutions to well-established processes and techniques that allow pipe fabricators to increase productivity without sacrificing the corrosion resistance of the stainless steel. This article will cover the basics of welding stainless steel tube and pipe for applications ranging from high purity food and beverage, pharmaceutical and petrochemical pipe to oil and gas applications. Within those basics, we will present best practices and new wrinkles on established methods that may help drive productivity in your shop while improving or maintaining the desired corrosion resistance. As a note: critical applications where processes are certified should not be altered without going through appropriate certification processes. Each process detailed in this article has been certified in critical applications and is meant to spur ideas as to how to move your own welding practices forward. Filler Metal Selection Critical in Controlling Carbon Levels Selecting filler metal for pipe fittings is about enhancing the properties of the weld and meeting the requirements of the application. Filler metals with an "L" designation, such as ER308L, provide a lower maximum carbon content, which can help retain corrosion resistance in low carbon stainless alloys. As an example: if you weld a 304L base metal with a standard 308 filler metal, you'll actually raise the carbon content of that joint and increase the chance of corrosion. In high purity applications – food, beverage, pharmaceutical – that low carbon content is critical for maintaining corrosion resistance. Conversely, a filler metal with an "H" designation provides higher carbon content for applications requiring greater strength, particularly at high temperatures. Filler metals with higher silicon levels, such as ER309LSi, increase weld puddle fluidity, improve tie-ins and increase travel speeds for greater productivity. The 309 series filler metals are also particularly adept at joining dissimilar stainless steels and in overlay applications. When welding stainless steels, it's also important to select a filler metal with low trace (or "tramp") elements. These are residual elements in the raw materials used to make filler metals. They include tin, antimony, arsenic, phosphorus and sulfur, and can have strong effects on corrosion resistance. Controlling Sensitization with Filler Metals, Interpass Temperature Control Sensitization is the primary cause of the loss of corrosion resistance and is affected by the chemistry of the base material and filler metal, as well as the temperatures at which the weld cools. Chromium oxide is the "stainless" layer of stainless steel. If you raise the carbon levels in the weld and neighboring heat affected zone, it forms chromium carbides, which tie up the chromium, preventing the formation of chromium oxide. This in turn allows the steel to corrode or it will not have the intended corrosion resistance. There are three primary ways to combat sensitization: the first is to use a low carbon base and filler metal to reduce or eliminate carbon in the welding application. This method, however, is not always practical as carbon is a vital alloying ingredient in some applications. The second is to minimize the time the weld and heat affected zone spend at temperatures conducive to sensitization. That range will vary depending on whom you ask, but a general consensus puts that range between 500- and 800-degrees Celsius. The shorter the time spent in that temperature zone, the less damage that accrues from the heat of welding. As such, it is important to adhere to maximum interpass temperatures identified in welding procedures. The goal in multi-pass applications should be to use as few passes as possible and weld at the lowest heat input possible to achieve faster cooling. The third is to use filler metals with special alloying ingredients to prevent the formation of chromium carbides. For instance, titanium and niobium can be alloyed into the filler metal and help prevent reactions between chromium and carbon. These elements also have strong effects on strength and toughness, limiting the applications in which they are useful. They also do not provide any benefit to the areas farthest away from the weld in the heat affected zone. Shielding Gas Critical in Retaining Corrosion Resistance Welding stainless steel tube and pipe traditionally requires a back purge of argon. In non-critical applications, where cost is a driving factor, nitrogen can also be used as a back purge but it may lead to the formation of some nitride compounds in the weld root, which sacrifices some corrosion resistance. This can be an acceptable trade-off in applications such as stainless steel piping for large compressed air systems and hydraulic fluid systems where water is not normally present inside the pipes and the risk of corrosion from the inside is low. Straight argon is recommended for gas tungsten arc welding (TIG) of stainless steel tube and pipe. Shielding gas selection for wire processes is more complicated. Traditionally, MIG welding has relied on mixtures of argon and carbon dioxide, argon and oxygen, and 3 gas mixtures based on helium, argon and carbon dioxide. These mixes usually contain mostly argon or helium, with carbon dioxide comprising less than 5 percent of the total gas mix. That is because the carbon dioxide can decompose in the arc and contribute carbon to the weld pool, creating a sensitized weld that is vulnerable to corrosion. Pure argon isn't used with the MIG processes because it doesn't easily support a stable welding arc. Other trace constituents like carbon dioxide and oxygen can serve this role. Argon and oxygen gas mixes can only be used to weld in the flat position because the oxygen makes for a very fluid molten weld puddle. Argon/carbon dioxide in combination with Pulsed MIG can be used to weld in all positions, as can the Tri-Mix shielding gas mixtures. Flux-cored wires for welding stainless steel are designed to run on traditional 75/25 percent argon/carbon dioxide mixes. The flux ingredients prevent the carbon contributed by the shielding gas from contaminating the weld and the fluxing action of the slag covering scavenges the excess carbon and keeps it from entering the weld deposit. 304 stainless steel can be successfully welded using the Regulated Metal Deposition (RMD?) process without a back purge. This is not true for duplex stainless steels. These must be purged with an inert gas such as argon. Weld Preparation and the Importance of Fit-Up A discussion on welding stainless steel tube and pipe is not complete without a discussion on joint preparation. The normal trappings of welding stainless steel apply: use dedicated brushes, files and grinders that never touch carbon steel or aluminum. Cleanliness is critical. Even trace elements of foreign materials incorporated into the weld joint can cause flaws and lead to reduced corrosion resistance and strength. Because stainless steel is so sensitive to heat input to maintain its properties – both in shape and corrosion resistance – the way the pipe is cut and beveled can also have a detrimental effect on the weld. Any gap or lack of fit-up requires the welder to add more filler metal and can slow the welding process down, leading to buildup of heat in the affected area. You want as close to perfect fit-up as possible, especially on sanitary and high-purity tubing. The problem of corrosion of steel pipes in hot water supply systems is very relevant in Russia. In a number of cases, the accelerated corrosion of pipelines and fittings installed in hot water supply networks is observed. The purpose of this study is to investigate the mechanism of corrosion of steel zinc-coated and non-galvanized pipes in hot water supply systems, to analyze the causes of corrosion and to develop methods for identifying active corrosion processes occurring in water supply systems. According to literature review the microstructure and composition of the zinc coating and the methods of its application are studied. A SEM/EDS study of the structure and elemental composition of inner zinc coating on new and used steel galvanized pipes is conducted. This study shows the nonuniform distribution of zinc layer which can lead to a rapid corrosion of both the zinc layer and the metal substrate and the development of pitting corrosion. A structure and composition of corrosion sediments formed on the inner surface of pipes was studied. The different causes and factors of steel corrosion in hot water are considered and discussed. A method of corrosion identification of galvanized pipes and heat exchange equipment based on the determination of corrosion products, in particular zinc and copper, was proposed.
Дата Публикации: 21-11-22
What is a good thermal paper roll?
Описание: What is a good thermal paper roll? Thermal Paper Rolls are used in thermal printers for customer receipts, tickets, etc. Obviously, there are lots of brands of thermal printers popular, such as Epson, Zebra. For each model of the printer, it has the fixed paper roll size it needed. This makes it easy for us to choose paper rolls for our printer. Paper Roll Size: The three key factors for roll size are width, diameter and length. The most popular width is 57mm (2 1/4″) and 80mm (3 1/8″), while 60mm, 70mm & 110mm for some other printers. For the diameter, it varies from 30mm to 250mm. Here comes length of roll. In a fixed paper roll size, such as 80x80mm, the lower paper gram mage is, the long meters this roll contains. You can use this roll for longer time. What is a good thermal paper roll? Do not say it is just a piece of paper. Paper is crucial to the machines. For the specific printer, the paper roll size is fixed. So here comes the paper quality. When you get a paper roll at hand, please see the whiteness, smoothness, image sensitivity. It's your choice for the whiteness while it does not affect the usage. For bad quality thermal roll, it is rough and coarse on front and back of paper. It is not lint free, so it leaves powder inside of the printer when you use it. This is harmful to the printer and will reduce the life span of the machine. To protect it, please pay attention to paper smoothness. Image sensitivity is another important factor. People will find they see the image is clear or fuzzy on receipts from different shops. It does. Thermal Paper is coated with a chemical that is why it changes colors when exposed to heat. If the coated chemial is even and enough, the text showed on paper will be clear, black and crisp. A flame on back of paper for one second can change color of paper. A fingernail swiped quickly across the paper will also change it. This is the same theory. Please make sure the image is even and clear. Thermal paper has a specialty coating that allows inkless printing and gives excellent results on printing as it provides reliable, speedy and high definition images. Thermal paper rolls are cost effective as they have lower maintenance costs. Furthermore, thermal printing technology is quieter as compared to its alternatives, which offers a pleasant experience when working with high volumes of printing. Key manufacturers such as Appvion are adopting latest printing technologies such as Techkon SpectroDens for thermal paper rolls to achieve excellent printing results. Attributing to their reliable and durability, 80mm thermal paper rolls finds application in various end uses. For instance, retailers use thermal paper rolls for point-of-scale applications such as super stores, grocery store, and ATM banks. In addition, ticket agencies and lottery systems, which require accurate and large volume printouts, also rely on thermal paper rolls. Thermal Paper Rolls Market: Dynamics The advent of digitalization in developing regions such as India has been driving the need for POS systems and subsequently, escalating the demand for thermal paper rolls in the market. In addition, the rising importance of labelling against the counterfeiting of products has been having a positive impact on the demand for thermal paper rolls. Moreover, thermal paper offers excellent coloring capability at high speeds and a highly durable finish that doesn't fade easily. This feature allows printed bar codes to be used in POS food labelling & other applications during their manufacturing and shipping, which has been escalating the demand for 3 1/8'' thermal paper rolls, globally. On the other hand, the usage of BPA in thermal paper has a negative impact on human health, which may hamper the growth of the thermal paper rolls market in the near future. Therefore, many retailers are adopting digital receipt software programs that work with existing POS systems and they print customer receipts only on request in order to minimize the usage of thermal paper. This intelligence report by TMR is the outcome of intense study and rigorous assessment of various dynamics shaping the growth of the market. TMR nurtures a close-knit team of analysts, strategists, and industry experts who offer clients tools, methodologies, and frameworks to make smarter decisions. Our objective, insights, and actionable analytics provide CXOs and executives to advance their mission-critical priorities with confidence. The scrutiny of the various forces impacting the dynamics of the market, and key and associated industries, guides enterprises in understanding various consumer propositions. Our clients leverage these insights and perspectives to enhance customer experience in the fast-paced business environment. All our insights and perspectives are broadly based on 4 Pillars or Stages: ASBC-S, which offer an elaborate and customizable framework for the success of an organization. The essence and the roles of these in organizational successes are highlighted below: Agenda for CXOs: TMR, through the study, sets the tone for agendas that are pertinent to CEOs, CFOs, CIOs, and other CXO executives of businesses operating in the market. The perspectives help our clients to bridge the gap between agenda and action plan. TMR strives to offer guidance to CXOs to undertake mission-critical activities empowered by various business analysis tools, and boost the performance of the organizations. The perspectives guide you to decide on your own marketing mix that align well with the policies, visions, and mission. Strategic Frameworks: The study offers how organizations are setting both short-term and long-term strategic plans. Our team of experts collaborate and communicate with you to understand these to make your organizations sustainable and resilient during tough times. The insights help them decide sustainable competitive advantage for each business units. Benchmarking for Deciding Target Markets and Brand Positioning: The assessments in the study provides a scrutiny of marketing channels and marketing mix. Our various teams work synergistically with you to help identify your actual and potential direct, indirect, and budget competition areas. Additionally, the study helps you decide most effective budgets for various processes and promotional activities. Furthermore, the study guides you to set benchmarks for integrating people and processes with the 4Ps of marketing. Eventually, this will empower you to find out unique propositioning strategies and niches. Business Composability for Sustainability (C-S): Constant strategy planning for sustainability characterizing our C-S framework in the report has become more relevant than before in the face of disruptions caused by pandemics, recessions, boom and bust cycles, and changing geopolitical scenario. The TMR study offers a high level of customization to help you achieve business composability. Composable enterprises are increasingly gaining the attention of CXOs in order to help them combat market volatility. Our analysts and industry experts help you wade through such uncertainties and guide you to become a smart sustainable business in entirety. With a robust experience in creating exceptional market reports, Transparency Market Research has emerged as one of the trusted market research companies among a large number of stakeholders and CXOs. Every report at Transparency Market Research goes through rigorous research activity in every aspect. The researchers at TMR keep a close watch on the market and extract beneficial growth-boosting points. These points help the stakeholders to strategize their business plans accordingly. TMR researchers conduct exhaustive qualitative and quantitative research. This research involves taking inputs from the experts in the market, focused attention on recent developments, and others. This method of research makes TMR stand out from other market research firms. Here's how Transparency Market Research helps the stakeholders and CXOs through the reports: Inculcation and Evaluation of Strategic Collaborations: The TMR researchers analyze recent strategic activities like mergers, acquisitions, partnerships, collaborations, and joint ventures. All the information is compiled and included in the report. Perfect Market Size Estimations: The report analyzes the demographics, growth potential, and capability of the market through the forecast period. This factor leads to the estimation of the market size and also provides an outline about how the market will retrieve growth during the assessment period. Investment Research: The report focuses on the ongoing and upcoming investment opportunities across a particular market. These developments make the stakeholders aware of the current investment scenario across the market. Disclaimer: This market research study is an ongoing effort and extreme care has been taken to maintain the highest levels of accuracy at all stages. However, in the light of the rapidly evolving business dynamics, some region-specific or other segment-specific changes may take time to be part of the study. Retail businesses are well aware that to function seamlessly and serve customers in the best way possible, using specific elements is essential. Those items mostly include pricing guns, shopping bags, signage, and most importantly, thermal papers. Retailers use thermal paper to print receipts, and it generally comes in a paper roll. You probably know if you have noticed in a boutique, stationery, or grocery store that it is the thermal printing device, which shoots out the receipt with transaction details. Thermal papers are unlike the normal ones, and you can understand that quite well by merely feeling them. A retail business owner can save a considerable amount of money by investing in thermal papers instead of ribbons or ink rollers. However, when it comes to purchasing thermal papers, certain key things you need to take into consideration. Read the following to know what you should look for when shopping for 57mm thermal paper rolls online. It might look to you at first glance that all thermal paper rolls are similar and of the same quality. However, it isn't. If you visit an Online Papers Rolls Shop Tauranga, you will find thermal paper rolls are available in an extensive range of quality levels. Ensure that you get premium-quality paper rolls for your retail business because the sub-standard ones mostly leave behind residue on the ribbon, adversely impact the printing procedure, and increase the risk for damage to your thermal printer. On the market, thermal paper rolls are available in a variety of lengths and thicknesses. To get your hands on the right thermal paper to meet your requirements, it is of the utmost importance to know the precise model of the thermal printer. Aside from the width, you can also select the length of the thermal paper roll. Opting for a longer roll will help you significantly to print more receipts. Making a budget before you shop for these paper rolls is imperative. Research well and compare prices of high-quality paper rolls available in different online stores. Once you find paper rolls of decent-quality, enough long, and affordable, you should purchase those without delay. Also, try to look for online stores that offer great discounts for bulk 2 1/4'' thermal paper roll orders. If you visit a well-known Online Pencil Store in NZ or any store where office consumables are available, chances are higher that you will get discounts if you purchase thermal paper rolls in bulk. So, even if you run a small retail store and usually require a handful of thermal paper rolls, you should buy them in bulk to save a considerable amount of hard-earned money. You will certainly be able to get your hands on the right paper rolls to meet your business requirements without any hassle if you consider the critical factors mentioned above.
Дата Публикации: 21-11-22
Glass vs. metal baking pans
Описание: Glass vs. metal baking pans Size isn't the only thing that counts when choosing a pan from the many in your cupboard. The material it's made of will affect both the baking time and the color of your breads, pies, cakes, and brownies. Glass pans give food a darker, browner crust, so they're generally best for breads and pies, which benefit from a deeply baked exterior. Because of the way glass transfers heat in the oven, it will bake both faster and darker than most metal pans (the exceptions are very dark, heavy-gauge metal pans, like the black cake pans used in professional kitchens. These intense heat conductors cook quickly and will also turn out appealing, dark crusts.) Lighter-colored pans give you a paler crust, which is what you want with delicate cakes and brownies. Light-colored aluminum and shiny stainless-steel pans reflect more heat than glass and dark metal pans. This may mean your baked goods will need a bit more time to finish cooking, but it also means the sugar and chocolate in these pastries won't be as likely to burn. Avoid flimsy muffin pan, which often bake unevenly and tend to warp at high temperatures. If you don't have a high-quality pan, it's worth investing in one (see "Pros Pick the Best Baking Sheets,"). Martha Stewart was placing two apple crisps on a sheet pan to catch the juices that bubble out during baking when she said, "If you saw how many sheet pans I owned, you would be quite horrified. I have a lot of sheet pans." And she's accumulated them over a long time: Ms. Stewart was first introduced to commercial loaf pan — the thick, uncoated aluminum baking sheets with 1-inch-high rims and rolled edges — by Fred Bridge in the 1970s. She had a catering business in Connecticut, and he owned Bridge Co., a professional kitchenware store on 52nd Street in Manhattan. "That's where I really started learning about high-quality, restaurant-quality, long-lived equipment," Ms. Stewart said. "I bought my best things from Mr. Bridge." On her first TV show, two decades later, she used 9 inch round nonstick cake pan on set, showing them to home viewers repeatedly — though not intentionally. Like most professional chefs in America, and bakers in particular, Ms. Stewart relied on those pans even if she didn't showcase them. And yet this utilitarian piece of equipment has become a star. That can be attributed in part to a surge of sheet-pan recipes from food publications, cookbooks and bloggers, a new genre of weeknight cooking that provides an entire meal on the pan. Cousins of one-pot meals, sheet-pan suppers combine vegetables, protein and starch in a single piece of cookware, but offer a larger canvas to compose a range of shapes and colors. The actual cooking requires nothing more than passive waiting. If you've ever debated on baking a cake in a glass pan versus a metal pan, or had cookies burn on the bottom at 350 oF within a "reasonable" amount of baking time, this post is for you! Find out everything you need to know about baking pans and bakeware, from how the material and the colour of the pan have an impact on baking to why 7 inch in cm cake pan may warp, bend, or rust. The point of this post isn't to have you throw out all your bakeware and buy new. On the contrary, what I am hoping is that this post will help you better understand how your baking pans affect your baking and how to make adjustments so that you know how to make adjustments and adapt, regardless of what bakeware you're using! If you want to easily convert recipes from one pan size to another, I recommend investing in the complete baking conversion charts bundle to get conversion charts for ingredients, pans, temperatures, volumes, weights, and more. Every editorial product is independently selected, though we may be compensated or receive an affiliate commission if you buy something through our links. Ratings and prices are accurate and items are in stock as of time of publication. When you're diving into a recipe, it's always important to look at the ingredients. Checking to make sure you have everything on hand can make or break a dish. But is it just as important to take a look at the required bakeware for the recipe? The short answer—yes. Depending on what you're making, there certainly is a difference between a baking dish and a baking pan. Here's what you need to know to choose the right one. What's a Baking Dish? The term "baking dish" typically refers to an oven-safe rectangular dish made out of glass, stoneware or porcelain. Baking dishes also come in oval and square shapes, and they vary in size and depth. Glass, stoneware and porcelain don't conduct heat very well, so they take a while to heat up. But once hot, a baking dish will distribute heat more evenly. It's also important to remember that a baking dish has the ability to shatter. Be sure you're not putting a cold baking dish in a hot oven or using the broil setting to add intense heat. What's a Baking Dish Best For? Reserve baking dishes for desserts such as fruit crisps, cobblers and bread pudding. A baking dish is also perfect for savory dishes such as casseroles, potatoes au gratin, enchiladas and quiche. A baking pan refers to bakeware made out of metal, often aluminum. Aluminum is one of the best metal options for conducting heat, so the pan gets hot quickly. As the pan heats up, it transfers the heat to what you're baking. Baking pans can withstand higher temps and come in a huge variety of shapes and sizes, including multiple sizes of rounds, squares, rectangles, Bundts and cupcake pans. What's a Baking Pan Best For? Because of its heat conductivity, a baking pan is great for recipes when you need a bit of browning. Most commonly, a baking pan will be used for cakes, but you can also use a baking pan for treats such as brownies, muffins and breads. Use baking pans for savory items such as meatloaf and roast vegetables as well. Just be sure to consider acidity when making your decision. If your dish includes acidic fruits or vegetables, which can react with metal, consider making the switch to a baking dish for best results. You've undoubtedly heard about the benefits of a well-seasoned cast-iron skillet. Legends are spun about this heavily-coated, durable piece of cookware that's often passed down by generation after generation of home cooks. But have you ever considered the benefits of a well-seasoned sheet pan? That splotchy tray you use to cook countless weeknight dinners—the one you hide when guests come because you're afraid they'll think you don't properly clean your cookware—is nothing to be ashamed of. In fact, it's time to celebrate those splotches, to stop thinking of your pan as dirty and start considering it perfectly worn-in. That patina—which is really baked-on oil—carries a host of advantages. The darkened surface aids in the caramelization of whatever food is in direct contact with it. Epicurious food director Rhoda Boone always uses a well-worn baking sheet for roasting vegetables. "The seasoning gets the cut edges nice and golden brown," she says. "More so than vegetables cooked on a lighter baking sheet." She also prefers it for roasting chicken thighs and pork chops. Anna Stockwell, another Epi test kitchen editor, agrees. That dark discoloration on well-used pans functions as a sort of natural non-stick surface, which means that vegetables are less likely too stick, even without the help of parchment paper. And less parchment used in the kitchen means both less waste and less money spent at the grocery store. There are a few times you might want to avoid a seasoned sheet pan, warns Katherine Sacks, Epi's resident pastry expert. "They can be a bit dinged up, so for cake or cookies—where it's important for the surface to be flat—I would use as new a pan as possible." And if you're baking a light-colored cookie or pastry that you don't want to color and a well-worn pan is your only option, lining it with parchment will slow down the browning. Unlike your trusty cast-iron, you should keep washing your sheet pans regularly. A quick scrub with mild, soapy water is best to keep the pan from building up too much residue, and a quick dry will ward off rust. But there's no need to pull out the baking soda and vinegar or stress about the amount of elbow grease it will take to get your darkened pan looking shiny and new. Besides, there's no better way than a loved and dented sheet pan to add panache to your Instagram photos. Today, we're breaking down a question we've asked ourselves, oh, a million times: How do we adapt cake pan sizes in baking recipes? (Say, something calls for a 8x8-inch, but you only have an 9x9.) Alice will show you with just a little math. The brownie recipe you want to make calls for an 8-inch square pan, but your only square pan is a 9-inch. Should you risk it? Maybe you want to double or triple a recipe but you aren't sure which pan to use, or maybe you have a specific large pan but don't know how many times to multiply your recipe in order to fill it. The answers to these and similar questions (asked endlessly in cooking classes!) do not involve rocket science, but just enough elementary school math to calculate the area of a square, rectangle, or circle. I love the math (and I've included a little math review below if you want to brush up), but I'm sharing my chart in case you don't have my thing for math. The handy list below (or some basic math, also explained below) will tell you the surface area of your pan. Once you know the area of any pan, you can compare it to the area of another pan to see how much bigger or smaller it is. You can divide the area of a large pan by the area of a small pan to figure out how many times to multiply a recipe to fill the larger pan with the same depth of batter (more on that later). Just by glancing at the two pans, you might think that a 9-inch pan is very close in size to an 8-inch pan of the same shape, thus making it a reasonable substitute. But if you check the chart, you'll find that a 9-inch square pan is more than 25% larger than an 8-inch square pan. (The relationship between a 9-inch and 8-inch round pan is similar.) Such a considerable difference will result in a 9-inch batch of very thin brownies that may be over-baked by the time you check them for doneness (because thin brownies bake faster than thick ones). Knowing this beforehand, you can increase the recipe by 25% for results as thick than the original recipe intended. If you want brownies that are even a tad thicker than the original recipe, you can even increase the recipe by 33%. Here's what to do if you multiply a recipe and end up needing part of an egg: Set aside any whole eggs you need. Next, whisk the other egg to blend the white and yolk; weigh it (preferably in grams); then weigh out the fraction of the egg that you need for the recipe and add that to the whole eggs. If you need 40% of a 50-gram egg, that's 20 grams of the whisked egg. When egg whites and yolks are used separately, weigh and measure them in the same way, but separately. Add leftover egg parts to your morning scramble. See, no waste and still no rocket science! The chart (or your ability to do the math) is extremely valuable: Use it but don't be a slave to it. When I make brownies in a large quantity, I like them to be about the same thickness as they are in a small batch, so I stay close to the chart. But, when I increase the dimensions of a birthday cake, I often make it a bit taller than the original (in other words, I round up when multiplying) because the proportions are visually more pleasing. For example, if I am making a 12-inch round cake using a recipe meant for an 8-inch pan, I divide the area of the 12-inch round pan (113) by the area of the 8-inch round (50 inches) and get 2.26. But instead of multiplying the recipe by just 2.26, I might multiply it by 3 so that the cake will turn out tall and lofty. See: Love the chart, but don't let it bully you!
Дата Публикации: 21-11-22
How It Works: Gate Valves
Описание: How It Works: Gate Valves All valves are designed to stop, allow, or throttle the flow of a process fluid. Gate valves—one of the original valve designs—are ideally suited for on-off, primarily liquid, service. A gate valve functions by lifting a rectangular or circular gate out of the path of the fluid. When the valve is fully open, forged steel gate valves are full bore, meaning there is nothing to obstruct the flow because the gate and pipeline diameter have the same opening. This bore diameter also determines the valve size. An advantage of this fullbore design is very low friction loss, which saves energy and reduces total cost of ownership. Gate valves can have a rising or nonrising stem design. Rising stems are attached directly to the gate and provide a visual indicator of the valve position. Nonrising stems are generally threaded into the upper part of the gate and have a pointer threaded onto the top to indicate position. Nonrising stem designs are ideally suited for applications where vertical space is limited, in well applications, and where scraping or pigging is not required. Gate valves are designed with a sealing unit to provide a tight seal around the stem. Our patented single loaded-spring (SLS) stem seal design, used in thread and socket gate valve and WKM Pow-R-Seal double expanding gate valves, provides superior leak protection and a self-adjusting seal designed to reduce maintenance. Bonnets Gate valves generally have one of four types of bonnets, which provide closure to prevent fluids from leaking out of the valve. Screw-in bonnets are simple, durable sealing units that use pressure to seal. Union bonnets provide easy access to the valve body for applications that may require frequent maintenance or inspection. Bolted bonnets are generally used for larger valves in higher-pressure applications. Pressure seal bonnets are designed for services with pressure in excess of 2,250 psi . Applications Because of the diversity of construction materials, trim offerings, and design combinations available with pressure sealing gate valves, they are appropriate for a wide variety of applications. From high-temperature coking units to food and pharmaceutical services, gate valves can be trusted to reliably perform. The protected seat-face design of double expanding and slab gate valves eliminates degradation of the seat face caused by debris in the process fluid, which makes them ideal for liquid service. When additional protection is needed at points in pipeline applications where operational integrity is vital and the consequences of environmental exposure are higher, such as near waterways and municipalities, double expanding gate valves are a particularly wise choice. Our smaller 2- to 4-in nonrising stem version of the Pow-R-Seal API 6A expanding gate valve is commonly used in wellhead manifold systems because of its reliable mechanical seal and high pressure capability. Drilling manifold systems can also be easily designed to use certain gate valves, such as the Cameron DEMCO valve DM series, with space-saving and versatile mounting designs. In the power industry, NEWCO gate, globe, and check valves and DOUGLAS CHERO forged-steel gate, globe, and check valves are ideal for standard and critical applications, such as steam distribution in power plants. By replacing the body and bonnet flanges with a welded connection, the design of this valve eliminates a leak path, reduces weight, and simplifies the application of exterior insulation. This, in concert with the forged steel body, provides the highest integrity sealing available. For challenging subsea environments, where pressures are extremely high, temperatures are low, and operation is difficult, subsea manifolds that integrate valves and interface panels are used for critical isolation. The simple design of the Cameron RING-O subsea valve is ideally suited for integration into these systems and can be actuated manually, via ROV, or hydraulically for ease of operation. The research presented was conducted to quantify the effects of butterfly and forged flange gate valves located upstream water meters with diameters larger than 50 mm. Errors caused by these valves can have an enormous financial impact taking into consideration that a small percentage of variation in the error of a large meter is typically related to a significant volume of water. The uncertainty on the economic impact that a valve installed upstream of a medium size water meter leads to many water utilities to oversize the meter chambers in order to mitigate the potential negative errors. Most manufacturers approve their meters for a specific flow disturbance sensitivity class according to the standard ISO 4064-1:2018. Under this classification, a correct operation of the meters requires a certain length of straight section of pipe upstream the meter. However, this classification of the meters cannot consider all types of flow perturbances. For this study, two types of valves, butterfly and gate, were tested upstream ten brand-new water meters from six different manufacturers constructed in four different metering technologies: single-jet, Woltmann, electromagnetic and ultrasonic. In each meter unit was tested at five flow rates, from minimum to the overload flow rates. The tests were conducted with valves set in different orientations, closing degrees, and upstream distances from the water meters under study. The research shows that the valves used can produce significant deviations in the measuring errors with respect the errors found for undistorted working conditions. In this article, PIF spoke to leading Scottish valve distributors, BM Engineering Supplies, to explore the similarities and differences between gate valves and knife gate valves. Although these shut-off valves are both used in on/off applications involving viscous fluids, there are some noteworthy design variances to consider when deciding which is best suited your process application. Here, we put the two head to head to see which valve type is better. How does a gate valve work? Gate valves open by lifting a round or rectangle-shaped gate out of the path of fluids. The sealing surface found between the gate and the seats is planar. As such, gate valves will often be used when a straight line of flow of fluids is required with minimum restriction. This popular shut-off valve type features a flat fate closure which slides either in and out, or up or down between two parallel plates to open and close the valve. With this in mind, gate valves are often used for shut-off operations as opposed to flow regulation operations as on or off are the only two settings available. One of the primary advantages afforded by using gate valves is that the pressure which drops can be very low when forged steel globe valves are fully open. While they are useful as on/off valves, they can also equally competent at performing bi-directional action. However, gate valves do require a large force to operate. Larger sized gate valves even require automatic actuators to operate. Gate valves are also not the quickest valve type to open or close. They also not the best suited for space-sensitive applications as they tend to take up more space compared to other valve types. In some cases, gate valves can also be prone to thermal expansion and shrinking when exposed to high-temperature fluctuations. As a result, this may provide applications with unwanted leakage. How does a knife gate valve work? Originally designed for the pulp and paper industry, knife gate valves perform exactly at their name implies. Stringy pulp would impinge between the wedge and sand seat of a normal gate valve to prevent flow shut-off. Knife gate valves feature a sharp edge to cut through the pulp and seal, a useful attribute which has seen this shut-off valve type become invaluable to applications which either deal with viscous fluids or ones which have a similar risk of impingement. Knife gates are cheap, easy to actuate and light. They are advantageous in applications involving viscous fluids such as sludge and slurry because their blades can cut through thick liquids with ease. As such, they are generally specified in larger sizes for the handling of thicker flows in demanding applications. Despite this, knife gates are known for their low-pressure limitations. As such, this makes them a less desirable shut-off valve for applications which require cleanliness or optimal hygienic conditions. Buy gate and knife gate valves from BM Engineering Supplies As an established and trusted valve distributor to the Scottish process industry, BM Engineering Supplies stocks a comprehensive range of both thread and socket globe valves and knife gate valves. For gate valves, BM Engineering is the Scottish partner for one of the UK's market-leading valve wholesaler, Leengate Valves. Their range of gate valves is approved to ISO 9001 standards and other relevant industry governing bodies. While for knife gate valves, BM Engineering partners with Orbinox UK, one of the world's leading manufacturers of knife gate valves.
Дата Публикации: 21-11-22
Great Challenges in Organic Chemistry
Описание: Great Challenges in Organic Chemistry The current scope of organic chemicals typically covers the theory and practice of (i) new synthetic methods and methodologies, (ii) isolation and synthesis of natural products, (iii) organic reaction mechanisms based on physical and theoretical chemistry approaches, (iv) bioorganic and medicinal chemistry, (v) organometallic chemistry, (vi) molecular recognition and supramolecular chemistry, and (vii) polymers and materials chemistry. These categories or branches have been established over years, reflecting the evolution of this field of chemistry on the basis of organic chemistry principles. The evolution will naturally continue in organic chemistry, which is based on clear understanding of the two- and three-dimensional chemical structures, as well as their relations to stability, reactivity, and other chemical properties. This characteristic feature of organic chemistry is very unique and unparalleled to any other disciplines in chemical sciences. Thus, the structure–property, structure–activity, and structure–function relationships of new organic materials compounds will keep serving as core themes in organic chemistry research. It is very clear that organic chemistry has been thriving by expanding its territories through exploration of the interfaces with other science disciplines. Thus, organic chemistry is undoubtedly serving as the core chemical science for the advancement of science and technology with clear goals to benefit human life and society. Accordingly, one of the grand challenges in organic chemistry is how to explore new frontiers at the interface of inorganic chemicals and other science or technology fields. In the past, the majority of interdisciplinary research was between two disciplines in two different laboratories. But now it is necessary to take multidisciplinary approaches, involving multiple disciplines and laboratories, for tackling significant scientific or technological problems. Under these circumstances, organic chemists must evolve into open-minded researchers who can effectively communicate and collaborate with other researchers from different disciplines. In order to achieve this goal, organic chemists should have good knowledge of other disciplines to understand the whole picture of the project. Thus, another grand challenge for organic chemists is how to evolve into a key player in a multidisciplinary research project by cultivating the ability to effectively communicate and collaborate with other project team members from different disciplines. Then another closely related grand challenge is how to cultivate the next generation of organic chemists who can survive and thrive in the broad interfaces of organic chemistry and other science/technology disciplines. Since traditional organic chemists enjoyed research only in their own comfortable playgrounds, these will be great challenges in research and education that organic chemists must face. Since "chemistry" has become the central core molecular science for energy, environment, sustainability, materials, biology, and medicine, great challenges in "organic chemistry" reflect more or less the same trend. In addition, advances in computing capacity and capabilities have opened avenues for big data treatment and analysis, systems chemistry, accurate simulations and predictions. Accordingly, it would be safe to say that the great challenges and successes in organic chemistry would reside at the interface with energy, environment, sustainability, materials, biology, medicine, and computer science. Now, let's move on to the examples of great challenges in branches of hypophosphorous acid and salts hypophosphite. At the interface with energy, solar energy and energy storage have been predominantly led by inorganic materials. Thus, there is a great challenge for organic chemists to create organic or hybrid materials to outperform existing inorganic materials. At the interface with sustainability and environmental science, a challenge is the development of efficient chemical processes converting industrial and agricultural wastes, industrial bi-products, carbon dioxide, greenhouse gases such as fluoroform, recovered plastics, etc., to useful chemicals without producing another waste. If these processes include efficient photochemical processes utilizing solar energy, it will be ideal. At the interface with materials, many great challenges can be envisioned, and already numerous research and development themes are ongoing in this field. The challenge here is how organic chemistry can play a key role in polymer and materials chemistry. The development of new, selective, and efficient polymerization methods and methodologies exploiting organometallic chemistry and organocatalysis make a huge impact on this endeavor. Supramolecular chemistry plays a significant role in the creation of novel organic, organometallic, coordination complex, and hybrid materials, wherein phosphorous acid and salts phosphite can make critical contributions. "Molecular machines" have already emerged as a new concept but how can organic chemists construct organic functional devices consisting of molecular machines with macroscopic motions? At the interface with biology and medicine, there are plethora of great challenges for organic chemists, e.g., epigenerics, DNA damage and repair, gene editing, nanomedicine, nano-formulations, molecular imaging, drug discovery and development, antibody-drug conjugates, next-generation fluorescence dyes for super-resolution imaging of living cells, just to mention a few. Chemical biology has evolved from bioorganic chemistry and biochemistry which provides powerful tools to investigate biological problems at the molecular level. For drug discovery and pharmaceutical sciences, synthetic organic and medicinal chemistry are indeed essential. However, the challenge here is how next-generation organic/medicinal chemists can play a key role in the whole drug discovery process, i.e., not simply serve as a contract research organization (CRO) for preparing library of compounds in a classical medicinal chemistry manner. Next-generation organic/medicinal chemists should be able to fully engage in drug design based on structural and computational biology. Physical organic chemists should be able to apply kinetics and thermodynamics analysis, especially in combination with molecular imaging, for the accurate evaluation of drug efficacy and mode of action, and better drug design. At the interface with computer science, there are numerous great challenges for organic chemistry. How can computational organic chemistry expand quantum mechanics analysis and prediction for organic reaction mechanism and catalytic cycles with increasing molecular sizes without X-ray crystal structures? How can computational organic chemists connect big data science with organic chemistry to explore "systems organic chemistry"? How can organic chemists and computational chemists work together to do rational design for new, selective, and efficient organic reactions, as well as metal catalysts using non-noble metals? How can organic chemists work with computational scientists to accurately predict chemical, physical, and biological properties of organic molecules through reliable structure–property, structure–activity, and structure–function relationship studies? How can computational organic chemists construct a reliable program for indicating most efficient synthetic routes to organic compounds with certain structural complexity? Of course, there are numerous challenges within the realm of organic chemistry and its branches. Creation of new chemical entities (NCEs) can only be achieved by chemists- no other science discipline can compete with chemistry in this respect. Then synthetic organic chemistry is responsible for all organic NCEs. Accordingly, both innovative and incremental advances in synthetic methods and methodologies are significant in this respect. In addition to the exploration of more selective, efficient and "greener" chemical processes, especially using metal or organic catalysts, development of highly efficient catalyst recovery and product separation technologies is critical, which has relevance to sustainability and environmental issues. Innovative synthetic methods and methodologies that enable late-stage modifications will significantly accelerate the analog design and synthesis in medicinal chemistry and drug discovery. Chemical informatics will play increasingly important role in synthetic organic and medicinal chemistry as well as organic materials chemistry. Computational analysis and design will also play critical role in medicinal chemistry, drug discovery, catalysis, supramolecular chemistry, and organic materials. Organic chemistry is a branch of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding. Study of structure determines their chemical composition and formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical (in silico) study.The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements, especially oxygen, nitrogen, sulfur, phosphorus (included in many biochemicals) and the halogens. Organometallic chemistry is the study of compounds containing carbon–metal bonds.
Дата Публикации: 21-11-22
Oil from pumpkin seeds
Описание: Oil from pumpkin seeds Pumpkin (Cucurbita pepo L.) is an annual climber and is in flower from July to September, and the seeds ripen from August to October . Pumpkin seeds oil is an extraordinarily rich source of diverse bioactive compounds having functional properties used as edible oil or as a potential nutraceutical. In recent years, several studies have highlighted the medical properties of pumpkin seed oil which is known as strongly dichromatic viscous oil . Researchers have so far focused particularly on the composition and content of fatty acids, tocopherols and sterols in pumpkin seed oil because of their positive health effects . Moreover, pumpkin has gained attention as an exceptional protective against many diseases, e. g. hypertension and carcinogenic diseases ; due to its health benefits such as antidiabetic , antibacterial , antioxidant and anti-inflammation . The determination of the biochemical and oxidative stability properties of raw material pumpkin seeds oil would contribute to the valorization of such oil especially in pharmaceutical, cosmetic, and food industries. Although much progress has been reached in the domain of modern medicine, we still notice the lack of efficient wounds healing treatments. The demand for natural remedies is rising in developing countries as natural substances may be effective, safe and cheap . Basic research has improved our understanding of enhancement and inhibition of wound healing and has given the basis for introduction of novel treatment methods . In this respect, the proprieties of Cucurbita pepo L. extracted oil have captured our interest. Despite all the proprieties of the pumpkin oil, and to the best of our knowledge, there is no investigation of this oil in wound healing potential. To this end, the current study aims to identify some physico-chemical aspects of the bioactive components of snow white pumpkin seeds oil as well as to highlight its hemostatic and healing potential effects on wound. The pumpkin (Cucurbita pepo L.) var. Bejaoui seeds were harvested in region of Sidi Bouzid (Centre of Tunisia). The seeds were authenticated at the National Botanical Research Institute Tunisia (INRAT) and the voucher sample was deposited at INRAT. The fixed oil was extracted by the first cold pressure from seeds using a mechanical oil press (SMIR, MUV1 65). However, "Cicaflora cream?" a repairing emulsion with 10 % of Mimosa Tenuiflora, was served as a reference drug from the local pharmacy. The remaining chemicals used were of analytical grade. The present study aimed to examine the effect of pumpkin (Cucurbita pepo L.) seeds supplementation on atherogenic diet-induced atherosclerosis. Rat were divided into two main groups , normal control and atherogenic control rats , each group composed of three subgroups one of them supplemented with 2% arginine in drinking water and the other supplemented with pumpkin seeds in diet at a concentration equivalent to 2% arginine. Supplementation continued for 37 days. Atherogenic rats supplemented with pumpkin seeds showed a significant decrease (p
Дата Публикации: 21-11-22
Failure analysis of a commercially pure titanium tube in an air conditioner condenser
Описание: Failure analysis of a commercially pure titanium tube in an air conditioner condenser Joining of titanium and stainless steel is challenging due to the formation of hard, brittle intermetallics. This study focuses on engineering ductile materials for joining transition metals. Friction welding of tube to tube-plate by an external tool, a novel solid state welding process was employed to join titanium tube and stainless steel tube plate. The interlayers engineered were copper, silver and Cu–Zn alloy. The micrographs revealed phase transformations in titanium tube and unaffected stainless steel base. Interface peak microhardness of 458 HV was observed for Ti/Cu–Zn/SS welded sample. The intermetallics formed were characterized by X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. A novel shear test procedure was developed to evaluate the maximum shear load. It was found that joints with silver as interlayer withstood the maximum shear load of 56 kN. The shear surfaces were further analyzed and investigated for fracture study. Titanium has today replaced copper alloys as the most favoured tube material for salt water cooled condensers. Main reason is the excellent corrosion resistance of titanium in chloride containing environments. The experience of titanium bar condensers is usually more than satisfactory, even if a few tube leaks have occurred. Possible damage mechanisms by high cycle fatigue, galvanic corrosion, water-droplet erosion and by flow-assisted corrosion are discussed. These perils can be handled by a number of adequate countermeasures analysed in laboratory work and meanwhile proven by plant service. The corrosion resistance of titanium in sea water is extremely excellent, but titanium 、nickel 、zirconium tube are expensive, and the copper alloy tubes resistant in polluted sea water were developed, therefore they were not used practically. In 1970, ammonia attack was found on the copper alloy tubes in the air-cooled portion of condensers, and titanium tubes have been used as the countermeasure. As the result of the use, the galvanic attack on copper alloy tube plates with titanium tubes as cathode and the hydrogen absorption at titanium tube ends owing to excess electrolytic protection was observed, but the corrosion resistance of titanium tubes was perfect. These problems can be controlled by the application of proper electrolytic protection. The condensers with all titanium tubes adopted recently in USA are intended to realize perfectly no-leak condensers as the countermeasure to the corrosion in steam generators of PWR plants. Regarding large condensers of nowadays, three problems are pointed out, namely the vibration of condenser tubes, the method of joining tubes and tube plates, and the tubes of no coolant leak. These three problems in case of titanium tubes were studied, and the problem of the fouling of tubes was also examined. The intervals of supporting plates for titanium tubes should be narrowed. The joining of titanium tubes and titanium tube plates by welding is feasible and promising. The cleaning with sponge balls is effective to control fouling. Titanium is the ninth most abundant element in the earth's crust and the fourth most commonly used structural metal. In nature, it occurs only as a mineral (ore) in combination with oxygen or iron (rutile, TiO2, or ilmenite, FeTiO3). Titanium is a lightweight material whose density is approximately 60 percent of steel's and 50 percent of nickel and copper alloys'. It was recognized in the 1950s as a desirable material for aerospace applications—especially airframe and engine components. In the 1960s and 1970s, titanium was considered for use in vessels and heat exchangers in corrosive chemical process environments. Typical applications included marine, refinery, pulp and paper, chlorine and chlorate production, hydrometallurgy, and various other oxidizing and mildly reducing chemical services. In the 1980s and 1990s, titanium began to be used for many nontraditional applications, including tubulars for geothermal energy extraction and oil and gas production, consumer goods (such as sporting equipment), food processing, biomedical implants, and automotive components. According to the U.S. Geological Survey (USGS), 52 million pounds of titanium were produced in the U.S. in 2000; worldwide, more than 100 million pounds were produced. Titanium sponge is obtained by reacting rutile ore with chlorine and coke, followed by magnesium (Kroll) reduction and then vacuum distillation to remove excess magnesium and magnesium chloride. Titanium sponge is pressed into blocks to make a consumable electrode and then melted in an inert environment under vacuum to produce a titanium ingot. Titanium is well-known for its unique combination of properties, which include low modulus of elasticity, stable and steadfast oxide film (which provides excellent corrosion and erosion resistance), and a high strength-to-density ratio. Titanium's fabricability, weldability, and formability make possible its use in many shop and field operations. Although gas tungsten arc welding (GTAW) is the primary joining process, many other procedures are suitable. Titanium's weld characteristics are similar to those of stainless steels' or nickel alloys', with surface cleanliness and inert gas shielding being important. Fabricators often perform seal welding and butt welding operations in the shop and the field. As for formability, titanium can be bent, cold-formed, and drawn readily. Furthermore, most industrial titanium alloys do not require stress relief annealing after cold forming. Titanium Tube and Pipe—Types and Uses Welded titanium tube is available in outside diameters (ODs) from 0.5 to 2.5 inches and wall thicknesses from 0.020 to 0.109 in. Welded pipe is available in standard industry sizes from 0.75 to 8 in. nominal OD with nominal wall thicknesses in Schedules 5, 10, and 40. Seamless pipe with ODs from 2 to 20 in., wall thicknesses from 0.25 to 2.0 in., and lengths to 60 feet also can be made. Welded titanium raw materials and pipe can be tested with many of the same techniques used for steel tube and pipe. Eddy current, pneumatic, and ultrasonic testing all are applicable to titanium. Procedures for eddy current and ultrasonic testing can be used to meet or exceed American Society for Testing and Materials (ASTM) B-338 and to help ensure tube reliability. In terms of cost, titanium is competitive with higher-end specialty steels and alloys. In fact, if analyzed on a life cycle basis, titanium often is more attractive economically. This stems from titanium's useful life—20 to 40 years or more—and ease of maintenance. Furthermore, titanium's exceptional corrosion resistance often allows a zero corrosion allowance. This means that thinner-walled titanium plate or pipe may be substituted for other materials with heavier walls. When titanium and other materials are analyzed, they must be compared by their cost per linear foot, not by their cost per pound. Because titanium is a relatively low-density material, its cost per pound is greater than for most other metals. With their increasing availability, titanium and titanium-alloy tubulars will continue to meet many challenges in chemical processing, oil and gas production, automotive, and consumer applications. The titanium industry's large excess capacity means it should be able to accommodate new applications and emerging markets for titanium with little or no trouble. R.L. Porter is a corrosion engineer and C.P. Clancy is general manager of commercially pure products for RMI Titanium Co., 1000 Warren Ave., Niles, OH 44446-0269, phone 330-544-7633, fax 330-544-7796, e-mail PorterRLP@aol.com, Web site www.rti-intl.com. RMI Titanium Co. provides titanium in a variety of forms—bloom, billet, sheet, welded tube, seamless pipe, and plate—for applications such as aerospace, automotive, deep-sea oil and gas exploration and mining, and sports equipment; parent company RTI International Metals Inc. manufactures and distributes extruded shapes and provides engineered systems for energy-related markets and environmental engineering services. The commercial production of titanium plate, sheet, strips, and bars is carried out using hot and cold rolling mills to achieve the necessary reductions and desired shapes. Rolling may be defined as the reduction of the cross-sectional area of a piece by compressive forces applied through rolls. Cold rolling is carried out at temperatures below which the rate of strain hardening is greater than the rate of recrystallization. When reduction is carried out above such a temperature, the process is termed hot rolling. The major quantity of titanium plate, sheet, strips and bars is processed using hot rolling techniques. The commercial production of titanium plate, sheet, strips, and bars is carried out using hot and cold rolling mills to achieve the necessary reductions and desired shapes. Rolling may be defined as the reduction of the cross-sectional area of a piece by compressive forces applied through rolls. Cold rolling is carried out at temperatures below which the rate of strain hardening is greater than the rate of recrystallization. When reduction is carried out above such a temperature, the process is termed hot rolling. The major quantity of titanium plate, sheet, strips and bars is processed using hot rolling techniques. The forged billets, whose surfaces have been descaled, are rolled between 1350 and 1500°F (730 and 815°C). This temperature is approximately 200°F (110°C) lower than the forging temperature. Titanium can be continuously rolled at temperatures as low as 1100°F (595°C). As the thickness of the material to be rolled is decreased, the temperature of the piece must be considerably lowered to minimize surface contamination. A careful choice of pass sequences to obtain a certain reduction must be made when rolling titanium. Pass sequence refers to the number of reductions taken and percentage reduction of the piece per pass. Continuous sheet and strip are best cold- or hot rolled with the application of back and forward tensions to reduce the friction in the roll gap. In cold rolling thin sheet, extremely tight roll settings are required to produce uniform cross section. Extrusion is the shaping of metal into a chosen continuous form by forcing it through a die of the desired shape. Titanium can be extruded to produce rounds, squares, tubes, and other simple shapes. Typical extrusion temperatures range between 1800 and 1900°F (980 and 1040°C). Titanium metal has been observed to have better flow characteristics than steel. It more readily fills the die, causes less die wear, and maintains closer tolerances than do steels.
Дата Публикации: 21-11-22