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- Создано: 06-01-22
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Raw Material Supply: Many Issues to Manage
Описание: Raw Material Supply: Many Issues to Manage Active Pharmaceutical Ingredients (API) raw material variability is not always thoroughly considered during pharmaceutical process development, mainly due to low quantities of drug substance available. However, synthesis, crystallization routes and production sites evolve during product development and product life cycle leading to changes in physical material attributes which can potentially affect their processability. Recent literature highlights the need for a global approach to understand the link between material synthesis, material variability, process and product quality. The study described in this article aims at explaining the raw material variability of an API using extensive material characterization on a restricted number of representative batches using multivariate data analysis. It is part of a larger investigation trying to link the API drug substance manufacturing process, the resulting physical API raw material attributes and the drug product continuous manufacturing process. Eight API batches produced using different synthetic routes, crystallization, drying, delumping processes and processing equipment were characterized, extensively. Seventeen properties from seven characterization techniques were retained for further analysis using Principal Component Analysis (PCA). Three principal components (PCs) were sufficient to explain 92.9% of the API raw material variability. The first PC was related to crystal length, agglomerate size and fraction, flowability and electrostatic charging. The second PC was driven by the span of the particle size distribution and the agglomerates strength. The third PC was related to surface energy. Additionally, the PCA allowed to summarize the API batch-to-batch variability in only three PCs which can be used in future drug product development studies to quantitatively evaluate the impact of the API raw material variability upon the drug product process. The approach described in this article could be applied to any other compound which is prone to batch-to-batch variability. Whether producing biologic or small-molecule drugs, pharmaceutical manufacturers (sponsors and contract service organizations) must manage a complex network of raw material suppliers, which provide chemical and biological materials; including starting compounds, intermediates, solvents, cell lines, yeast, bacteria, cell-culture media and feeds, excipients, production materials such as tubing, single-use manufacturing equipment and packaging materials, among others. Ensuring that the correct materials have been received and that they meet quality and other specifications (such as manufacture under GMP conditions) can be a daunting task. Extensive collaboration with preferred suppliers and reliance on third-party vendors that can handle some of the workload are two strategies that can help simplify the issue and reduce supply chain risk. Growing Complexity The overall pharmaceutical supply chain is complex due to the nature of the drug development and commercialization process, which can extend for several years. Extensive and ever-changing regulatory requirements for not only manufacturing processes, but also the transportation and import/export of materials from basic starting ingredients to pharmaceutical intermediates, APIs and drug products further complicate the situation given the increasing globalization of the industry. For fine chemicals in particular, the growing complexity of the compounds being developed as drug candidates has resulted in more complex production routes requiring more steps (that might be performed at different facilities) and greater numbers of raw materials, including specialized compounds. An increasing percentage of drug candidates are highly potent and/or niche products for the treatment of smaller patient populations and require smaller volumes, leading to an increase in the use of multi-product manufacturing facilities. As a result, manufacturers find themselves dependent on a greater number of suppliers from varying locations around the world. Suppliers can in fact number in the hundreds and vary in size from small, specialized producers to large international chemical companies, each of which may have multiple production sites and their own supplier networks.1 Even small disruptions can have dramatic effects on such complex supply chains, and there are many potential causes of such disruptions.2 Geopolitical instability and natural disasters can interrupt production and/or distribution, thus affecting raw material availability. Variability in the quality of electronic chemicals can affect production yields and final product quality, safety and efficacy. Contamination of materials – accidentally or deliberately – is an additional significant concern. Rapidly changing market trends can be a further factor. For instance, the decline in demand for raw materials used in larger quantities in other industries can lead to the reduced availability for pharmaceutical applications. Alternatively, sudden increases in demand for non-pharma applications could also lead to reduced availability to drug manufacturers. The Upstream Supply Chain Security working group of the not-for-profit pharmaceutical and biotech industry consortium Rx-360 conducted a survey in August 2013 to identify issues of concern for the pharmaceutical industry regarding raw material supply chain security.3 The group found that nearly half of the respondents did not use supply-chain mapping (a tool for understanding the origins of pharmaceutical raw materials) for some or all of their materials or audit beyond their suppliers’ suppliers. Raw Material Variability One piece of good news – while the complexity of the pharmaceutical raw material supply chain has increased in recent years and a greater percentage of raw material production is now outsourced to companies in emerging markets, overall raw material quality and reliability has increased.4 This news is substantial, because any variation in the quality of raw materials – whether chemical starting materials or glass vials for final product packaging – can have a direct impact on product yields, costs, regulatory submissions, availability and most importantly, patient safety. One thing that has changed, though, is the sensitivity of analytical methods used for raw material characterization.4 Higher levels of variability are in some cases now detected that were simply not possible to measure in the past. Expectations for quality and consistency have also increased, and raw material suppliers have responded by improving process controls. Excipients are one set of materials that have not received as much attention in the past, but have recently come in the spotlight, with new regulations under development or recently passed to implement quality requirements similar to those for other raw materials.5 In general, the variability of raw materials can be attributed to the presence of trace impurities that are toxic or can react with the desired compound and affect its properties. Biological contaminants also impact raw material quality.4 The presence of trace impurities or biocontaminants typically results from lack of appropriate process controls, inadequate handling/storage facilities, or insufficient analysis prior to product release. Suppliers, including repackagers, must implement effective process controls, audit their own raw materials vendors and be able to provide comprehensive documentation on their supply chains.4 Specific requirements and expectations should be outlined in quality agreements and based on deep knowledge that the drug manufacturers have gained about their processes and the raw material properties that can influence critical quality attributes.4 Manufacturers should also have comprehensive raw material management strategies in place that include risk assessments, segregated receiving and handling areas, release testing protocols, supplier audits, communication systems and the quality agreements mentioned above. One challenge is the lack of any standard requirements for raw material management. Industry groups like the BioPhorum Operations Group (BPOG) are looking at this issue.4 Need for Raw Material Supply Chain Transparency Despite the importance of supply chain transparency for reducing raw material variability, there remains a real need in the pharmaceutical industry, as revealed by the results of the Rx360 survey. The increasing complexity of pharmaceutical raw material supply chains is introducing increasing risk. At the same time it is making it increasingly difficult to gain a deep understanding of entire supplier networks. Supply chain mapping has become essential for pharmaceutical companies to be able to track changes in their supply chains – such as the movement by suppliers of raw material production to different facilities or the switching by direct suppliers to different material vendors.1 These types of changes have the potential to impact raw material quality that could impact drug product safety or efficacy. Without supply chain mapping they can easily go unnoticed and be difficult to identify as the root cause. Comprehensive mapping is no simple task, however. It places a significant burden on suppliers to provide information about their manufacturing sites and their supplier networks, often in slightly different formats, to many customers.1 Here again, the lack of an industry standard for supply chain transparency is a key issue. BPOG, Rx360, the Parental Drug Association (PDA), the Pharmaceutical Supply Chain Initiative (PSCI) and other industry groups, in conjunction with regulatory agencies, are working to address this problem. There are also companies that offer supply chain management services to the pharmaceutical industry. These firms can help pharmaceutical manufacturers map their supply chains, identify risks and implement systems that provide valuable information in real time for greater transparency and responsiveness.1 The Overall Goal: Risk Reduction In the last decade, the pharmaceutical industry has witnessed the terrible consequences of inadequate supply chain security; tragic deaths in 2008 due to contaminated heparin;6 disruption of the supply of key raw materials/building blocks and pharmaceutical intermediates following the devastating earthquake and tsunami in Japan in 2011;7 numerous recalls of parenteral drugs in recent years due to the presence of particulate contaminants from glass vials;8 and many patient illnesses from contaminated compounded products in 2014.9 Increased public awareness of these issues has led to new guidelines requiring manufacturers to have full visibility into their raw material supply chains.10 There is, as a result, a definite movement to reduce risk by performing risk assessments, implementing risk mitigation strategies and developing contingency plans.11 It would, in fact, be interesting to see what results Rx360 would obtain in 2016, if they repeated the 2013 survey. As a specific example, biologics manufacturers have steadily moved away from the use of animal-derived materials to a preference for chemically defined media and feeds for cell-culture manufacturing. They also have a greater awareness of the impact of raw material impurities on yield and productivity – knowledge they are sharing with their suppliers. In many cases they are requiring that all Trifluorochloroethylene CAS NO.:79-38-9 meet higher quality specifications rather than limiting this expectation to a few key ingredients.11 Suppliers have responded by developing special, higher grade product lines that include provision of extensive supply chain and analytical testing documentation.11 Multi-Pronged Solutions Needed As mentioned above, to achieve real raw material supply chain security and transparency it is essential to develop a supply chain management strategy that involves supply chain mapping, analytical/ release protocols and much more. Close collaboration with preferred suppliers can help lead to simplification of the supplier network. The use of reliable third-party partners, such as contract development and manufacturing organizations (CDMOs), to manage much of the supply chain, and particularly the sourcing of materials from emerging markets, can also be a component of an effective strategy. With respect to testing, it is essential to confirm the identity of each material that comes into a manufacturing facility, as well as its purity and the presence of any impurities. Testing is conducted following methods specified in regional pharmacopeias (Europe, US, Japan) and other standards and regulations, but often also includes additional methods that manufacturers deem appropriate/necessary for ensuring raw material quality.12 Raman, near-infrared, Fourier-transform infrared, and nuclear magnetic resonance spectroscopy are commonly used techniques for confirming the identity of raw materials. Mass spectroscopy is much more sensitive, but is typically too expensive for routine raw material release testing; alternatives include blotting, capillary electrophoresis (CE), various enzymatic methods (e.g. enzyme-linked immunosorbant assay (ELISA)- based methods) and high-performance liquid chromatography (HPLC).12 The introduction of handheld instrumentation is helping pharmaceutical companies meet the requirements for 100% identification of raw materials.13 These lightweight devices are simple to operate and can be set up to provide a pass/fail reading when determining the identity of the material in a given package. Materials can be evaluated in the receiving area, eliminating the need to burden the QC department with large numbers of samples. In addition, materials stored in clear packaging can be evaluated without opening the package.13 Effective management strategies are also essential for achieving true supply chain security and transparency. The use of cross-functional sourcing teams with representatives for different types of raw materials (chemicals, packaging materials, etc.) can more effectively integrate risk evaluation efforts and the implementation of risk management programs.2 This approach is particularly effective when combined with work streams targeting the different raw material types. Specialized software and other technologies designed for supply chain management in the pharma industry are also crucial for achieving ongoing, real-time visibility into the full raw material supply chain.2 For manufacturers looking to source Hexafluoro-1,3-Butadiene CAS NO.:685-63-2 from suppliers in emerging markets, ensuring supply chain transparency can be quite challenging. In this case, it is reasonable to turn to a reliable third-party vendor with an established track record for serving as a high-quality supplier of these materials. Such vendors have established relationships with these suppliers and have a much larger demand volume, enabling them to gain access to necessary information. In many cases they are also manufacturers and have the capability to perform appropriate analyses and purify materials if necessary.14 CDMOs, for example, often have very strong relationships with preferred raw material suppliers who have a deep understanding of the needs of the pharmaceutical industry.15 Through their increased purchasing power and ongoing audit and monitoring programs, these CDMOs have the ability to influence supplier performance and ensure comprehensive supply chain transparency for reduced risk. Often price and scheduling advantages can be achieved as well.15 Other benefits of using effective CDMOs as sourcing partners include access to a larger number of qualified suppliers, their extensive regulatory and import/export knowledge and state-ofthe- art supply chain management systems and technologies.15
Дата Публикации: 06-01-22
The benefits of digital label printing
Описание: The benefits of digital label printing Customisation is the number one key differentiator for many industries these days. Manufacturers are taking advantage of new technologies to deliver short-run products to customers and, even in mass-produced items, the right label can tell an entire story about a product. Labels are the physical representation of a brand; they tell consumers everything they need to know about the product, and they differentiate the product even in a crowded market. Some of the world’s most successful brands are recognisable by their labels alone. This highlights the crucial importance of getting labels right. Some labels need to quickly send a brand message or differentiate a product. Others need to convey a large amount of information in a relatively small space. All labels need to be high quality and reliable. Most importantly, they need to make the product stand out on the shelf and create a connection with the consumer. This can be achieved with decorative effects like spot UV and foiling which can now like labels, be done digitally As well as having a standout design, label printing needs to be high quality. Barcodes need to be crisp and clear, text needs to remain legible, and images and colours need to be reproduced accurately. Whether you’re printing labels for a local cottage industry or a global chemical manufacturer, these requirements remain the same. Digital Label Printer is growing Like almost everything else in the world, label printing has gone digital. The huge and growing demand for labels has meant that traditional label printing methods simply can’t keep up with demand. Digital label presses account for close to 30 per cent of all narrow-web press installations worldwide and are forecast to make up close to 40 per cent or more of installations. And, digitally printed labels make up close to one-fifth of all print jobs by value. Digital label printing offers clear benefits Digital label presses offer nine key benefits over analogue printing methods: Seamless workflow that minimises errors and speeds up processing times. Lower costs by eliminating the need for plates, chemicals, and related processes. Improved supply chain efficiencies and reduced need to store labels due to just-in-time production. Flexibility to produce customised labels, variations, and promotional labels. Improved environmental sustainability due to less waste and no chemicals. Ability to incorporate security features such as microtext, anti-copy features, and more. Track and trace capabilities by producing sequentially numbered or coded labels. Ability to offer shorter run lengths and flexible delivery times. Ability to attract new customers and enter new markets. What to look for in a digital label printer It’s important to choose a digital label printer that lives up to your business’s quality credentials. If your digitally printed labels look low-quality or can’t match the vibrancy of analogue-printed labels, then your customers will soon go elsewhere. The equipment you use will make all the difference. To offer UV Digital Label Printer, you’ll need to have both the hardware and the software in place. Here are eight things to look for when choosing the right solution for your business: Variable speeds to match the media used. Fast, accurate colour adjustments. High performance for all media types. Intuitive operation using on-screen instructions. Versatility such as ability to overprint on pre-printed media and food grade toner for indirect packaging. Fast operation for quicker job completion. Continuous, high-quality print runs without the need for recalibration. Accurate print registration. How digital solutions can help you leverage existing investments Investing in water based digital label printer requires careful consideration so you can achieve a strong return on investment. However, it’s not necessarily just about replacing analogue printing presses with digital ones. Adding a digital solution to your fleet can help you reinvigorate your analogue presses, keeping them busy with long-run jobs while your digital presses take care of customised jobs and short-run projects. Digital label printing provides commercial printers with opportunities to enter new markets and attract new customers. The flexibility and quality of digital printing, as well as the new technology that can be incorporated into digitally printed labels, opens a whole new revenue stream for label printers. Konica Minolta’s digital book printer solution incorporates market-leading hardware and software, as well as exceptional service by experienced specialist staff. To find out how you can add digital label printing to your offering and boost your business, contact us today. Digital printing has transformed label production over the last decade, but at BOBST, we believe that we are at the tipping point of another new chapter. The labels sector has been a pioneer for digital printing, and digital technology is now widely utilized and accepted. According to analysts, more than 30% of labels were produced digitally in 2020. Converters value the lack of plates and minimal set-up. At the same time, they face the question that has always followed digital print production – does it really measure up to the quality of conventional flexo? Is digital only really suitable for short runs? The conventional viewpoint is that flexo is best for high volume and/or high complexity and digital presses are suitable for short runs with 4 colors. Up until now, this has been generally true, but this is changing as digital technology continues to progress. To help assess just how far digital printing has progressed, we performed a practical real live test using the Mouvent LB702-UV equipped with 6 colors and white. In a single 8-hour shift with just 1 operator, it fulfilled a total of 21 separated jobs using 4 to 6 colors (some with white ink) on 4 different substrates (PP, PPE, transparent and metallized). You can see full details of the jobs in a summary at the end of the article. In total, 13 2,000-meter rolls were used, totaling 26 kilometers of substrates and delivering nearly 1.3 million labels. See for yourself in the short video below. Like most small and medium-sized enterprises, Singapore-based printing company iSuccess is always looking for new ways to streamline business operations, improve customer service and expand into new market segments. However, the firm which was established in 2000 and counts corporate organisations, advertising agencies, restaurants and schools as clients, had been held back by its focus on printing digital labels in sheets, rather than rolls as preferred by a growing number of customers. “It was a challenge to switch to continuous inkjet printing in roll form,” says Ng Swee Leong, director of iSuccess. “We couldn’t do it due to our inexperience with producing labels in rolls.” Additionally, iSuccess had to grapple with laborious tasks, such as die-cutting labels that had been printed with other press machines. “It was not only time- consuming especially when there was a large number of sheets to be die-cut, but also labour intensive as we needed to peel off excess stickers to reveal only the die-cut labels.” These challenges had impeded iSuccess’s ability to compete in a marketplace where customers increasingly demand high quality labels to be printed within shorter time frames. Outsourcing production was not a feasible option either, as that would mean losing control over production timelines, Ng says. That changed when iSuccess decided to purchase the Epson SurePress L-4033AW Digital Label Press, a short- run digital label printer that is easy to operate and makes short-run printing a breeze, enabling iSuccess to achieve higher productivity and profitability. “During the pre-sale process, Epson gave us a good impression of the machine, including its print quality and support we would get,” Ng says. “And during installation and post-sale support, the Epson team had demonstrated the printer’s efficiency.” Much of the SurePress L-4033AW’s production efficiency is attributed to the ease with which laser printer in roll form can be undertaken without the need for skilled operators. That was a boon for iSuccess’s production staff who could get up and running quickly after some guidance. The Epson SurePress L-4033AW Digital Label Press is easy to operate and makes short-run printing a breeze (above). The printer has a six-colour, industrial-quality, water-based ink set that produces a remarkable range of colours for professional and consistent results (right). Because the SurePress L-4033AW supports a wide range of label media that can be used for printing stickers, banners and posters, among other product and marketing materials, iSuccess now uses it to print labels that are not supported by its existing digital press. “Also, when there is a job where the quantity or die-cut requirements are not suited for sheet printing, we will use the SurePress L-4033AW to fulfil the order,” Ng says. More importantly, iSuccess has slashed the time required for printing and die-cutting. In a recent project, the company was able to print 50,000 labels within a day for Asus. “We also printed 5,500 labels for the Tunglok restaurant group within three hours upon receiving the order. Without the Epson printer, we wouldn’t be able to fulfil such orders.” Like most Epson printers, the SurePress L-4033AW features the acclaimed MicroPiezo inkjet technology to create output with smooth gradations and incredible colour quality.
Дата Публикации: 06-01-22
Critical review of energy storage systems
Описание: Critical review of energy storage systems This review article critically highlights the latest trends in energy storage applications, both cradle and grave. Several energy storage applications along with their possible future prospects have also been discussed in this article. Comparison between these energy storage mediums, as well as their limitations were also thoroughly discussed. Suggestions and solutions in mitigating some of these challenges in order to improve the overall performance of these energy systems have also been analysed in this investigation. In spite of the accelerated growth in home energy storage system, there is still a grave need for further investigations, in order to reduce their costs. Further research activities will reduce the cost of some of these novel technologies, thereby accelerating their commercialization as well as making them better competitors against traditional energy storage mediums. Energy systems are dynamic and transitional because of alternative energy resources, technological innovations, demand, costs, and environmental consequences. The fossil fuels are the sources of traditional energy generation but has been gradually transitioned to the current innovative technologies with an emphasis on renewable resources like solar, and wind. Despite consistent increases in energy prices, the customers’ demands are escalating rapidly due to an increase in populations, economic development, per capita consumption, supply at remote places, and in static forms for machines and portable devices. The energy storage may allow flexible generation and delivery of stable electricity for meeting demands of customers. The requirements for energy storage will become triple of the present values by 2030 for which very special devices and systems are required. The objective of the current review research is to compare and evaluate the devices and battery energy storage system presently in use and anticipated for the future. The economic and environmental issues as well as challenges and limitations have been elaborated through deep and strong consultation of literature, previous research, reports and journal. The technologies like flow batteries, super capacitors, SMES (Superconducting magnetic energy storage), FES (Flywheel Energy Storage), PHS (Pumped hydro storage), TES (Thermal Energy Storage), CAES (Compressed Air Energy Storage), and HES (Hybrid energy storage) have been discussed. This article may contribute to guide the decision-makers and the practitioners if they want to select the most recent and innovative devices and systems of energy storage for their grids and other associated uses like machines and portable devices. The characteristics, advantages, limitations, costs, and environmental considerations have been compared with the help of tables and demonstrations to ease their final decision and managing the emerging issues. Thus, the outcomes of this review study may prove highly useful for various stakeholders of the energy sector. The need for energy emerged as soon as human beings learned to cook food, although people were unknowingly benefitting from solar energy to protect their bodies from coldness and drying clothes in the sun etc. The first planned utilization of energy was from wood and fire. However, increasing awareness of nature for taking advantage of energy, various sources of energy were identified and put to versatile uses. People also acquainted to change forms of energy and storing it for the times when sources were not available, for example, solar energy at night, though the ways of conserving energy were very basic like storing wood under shelter and other safe places. However, increased populations and energy usage versatility added other sources like coal, steam, water, wind, and petroleum. The invention of electricity changed the whole scenario of energy. The olden sources of energy were replaced partially by the production and consumption of electricity. Some modern sources of energy like nuclear and renewable resources have been identified in the twentieth century. Presently, an energy mix is prevailing and being used in different parts of the globe. The demands for energy are increasing rapidly due to an increase in populations, economic development in developing countries, enhancement in per capita consumption, change in lifestyle, and supply at more remote places as stored energy. The world’s primary energy consumption was 149,634 and 157,064 Terawatt-hours (TWh) in 2015 and 2018 respectively (Ritchie and Roser, 2019). According to their estimate, the regional consumptions were 69,615, 32,936, 23,859, 10,822, 10,494, 8164, and 5367 TWh for Asia Pacific, North America, Europe, CIS, Middle East, South and Central America, and Africa respectively. Thus, the biggest consumers of energy were Asia Pacific and North America while Africa used the least quantum of energy in 2018. The Gulf Cooperation Council (GCC) countries are although low populated, but are high consumer of energy, even in comparison to some of the developed countries (Al-Badi and AlMubarak, 2019). The consumption of electricity in the GCC region has grown from just 51 TWh in 1990 to almost 536 TWh in 2015 whereas the per capita use has been recorded as one of the highest rates. It is estimated that the GCC countries will be consuming 1094 TWh by 2025 (Almulla, 2014). Such a pattern is mostly due to rapid economic development and significant change in the lifestyle. The household energy storage system necessarily require smooth, balanced, reliable and quality supply (maintaining constant voltage and frequency) to the customers without any breaks and potential damage to electrical appliances. The strong variations always exist in demand of electricity at different times. Hence, there could be certain times when the energy production will be more than demand and vice versa. Just to quote an instance, the peak demand of GCC countries in summer is twice the off-peak summertime requirement due to the running of air conditioners and is thrice of winter peak times (Al-Badi and AlMubarak, 2019). For balancing and matching the demand and supply, the storage of energy is a necessity. The present trends indicate that the need for energy storage will increase with high production and demand, necessitating the energy storage for many days or weeks or even months in the future. According to estimates, requirements for storing energy will become triple of the present values by 2030 while the stationary energy could dominate in quantities of electricity supply through grids (IRENA, 2017). The energy storage techniques and devices have been changed and modernized simultaneously along with increasing production and demand. The devices conventionally were magnets, batteries, dry cells, and capacitors. However, besides changes in the olden devices, some recent energy storage technologies and systems like flow batteries, super capacitors, Flywheel Energy Storage (FES), Superconducting magnetic energy storage (SMES), Pumped hydro storage (PHS), Compressed Air Energy Storage (CAES), Thermal Energy Storage (TES), and Hybrid electrical energy storage (HES) were developed for sustainable and renewable usage (Frackowiak and Béguin, 2001, Doetsch, 2014; Haisheng et al. 2009; Luo et al., 2015; Silva & Hendrick. 2016; Stanley, 2012; UCS, 2006). However, energy storage mechanisms also face many challenges as well (Mohd et al., 2008) because none is complete in all respects due to one or more limitations like storage capacity and form, string time, special structural or implementation requirements, energy releasing efficiency, and operation time (Yae, et al., 2016). In addition, there are cost, and environmental aspects like CO emissions (IEA, 2019) associated with the energy storage technologies, which must be identified and considered when planning and deciding the selection of technologies for installation in the grid systems of an area. The aspects identified above need to be elaborated through a systematic study from the literature so that valuable research work of earlier authors is gathered, understood well, and arranged in a good array to clarify the study areas, which can contribute to support and ease the decision makers and practitioners for selection of best energy storage devices and mechanisms for their particular grid systems. Considering the high importance and problems of electric energy storage, some aspects of this subject are being discussed and highlighted with support from the literature review. 2. A dynamism in the forms and sources of energy The types and uses of energy had been dynamically changing in history because Beltran (2018) regarded energy as a living, evolving, and residential energy storage system, which remained an integral part of civilizations and their development. The sun was the only source of heat and light while wood, straw and dried dung were also burnt. The horses and other animals, wind, and water were used for transportation, working in the fields, grinding grains, pumping water, and driving the simple machines in very earlier times. Later, the power of steam was harnessed which dated back to ancient Alexandria. The steam engines remained in use till the 17th and 18th centuries. Simultaneously, coal was also used for heating and production of steam from water. By the late 1800s, petroleum was introduced as a fuel and is still in wider use. Thomas Alva Edison installed the first electric light plant in the city of New York in 1880. (UCS, 2006). The invention of electricity revolutionized energy usage and consequently, industrial revolutions happened on the globe. Currently, electricity is the dominating form of energy all over the world. The introduction of nuclear energy started in the 1950s and was increasing rapidly, but the Chernobyl accident in Russia (1986) and some later incidents in India and other countries discouraged its spreading due to safety concerns and social pressure (King, 2019). The modern biofuels, wind, and solar are finding their way again while geothermal and marine technologies are new additions in the field of energy. Advances in technology, alternative energy sources, costs of energy and pressures of social issues associated with energy production are the driving forces behind the above changes, but the static fact is the consistent increase of energy utilization during the global history (Ritchie and Roser, 2019). Ritchie and Roser (2018) reported that the total global energy consumption in 2018 was 160,228 TWh while different energy production sources contributing to this huge production are oil, coal, gas, hydropower, wind, solar, nuclear, and other renewals. According to them, the biggest sources are Oil, Coal, and Gas contributing energy (TWh) as 54,220 (33.84%), 43,869 (27.38%), and 38,489 (24.02%), respectively. Thus, these three major sources are meeting 85.24% of global energy requirements. The respective shares of Hydropower, Wind, and Solar were 6.89% (11,034 TWh), 2.09% (3342 TWh), and 0.96% (1539 TWh). The contribution from nuclear resource was 4.43% (7109 TWh) and Other Renewals 0.38% (626 TWh). Due to CO2 emissions during electricity generation from fossil fuels, demand is increasing to shift gradually to renewal sources, but it is not possible in the short-term because demand of electricity may go thrice by 2040. According to estimates of World Energy Council (2019), global emission of CO2 might stabilize by 2030 and reductions could be expected afterwards. These days an energy mix (electricity, the solar, wind, and nuclear) is being consumed in various countries of the world. However, all the other forms contributed only less than 1% of the total energy utilization (BP Statistical Review, 2019, Ritchie and Roser, 2019). 3. Global status of the consumption of energy The energy consumption has increased tremendously after the industrial revolutions due to an increase in population, invention of new techniques and machines, economic development, accessing remote and far flanged areas, and big changes in the lifestyle. According to estimates, energy use was doubling in each decade in earlier times (UCS, 2006). Simultaneously, a significant increase also took place in the production of energy, especially electricity. Among other drivers of increasing demand for energy are selling the electricity even below the actual cost in GCC and some other countries, wastage due to usage and building designs, and lower efficiency of generation and delivery equipment (Al-Badi and AlMubarak, 2019). Nevertheless, production could not match demands in so many developing countries. According to estimates, the world’s primary energy consumption in 2015 remained as 146,000 terawatt-hours (TWh), 25 times higher than the year 1800 (Ritchie and Roser, 2018). As the data values are not mostly same when reported by different sources, in another report (BP Statistical Review, 2019), the global energy consumption was 136,129 TWh in 2008 and 161,250 TWh in 2018. There has been a 2.9% increase in consumption for the 10 years. World Energy Council (2019) while finding scenarios and exploring innovative pathways to 2040, contemplate that the globe will be entering in a new energy era promising enough, clean, and residential solar energy storage for all communities with increasing uses and users. About 10% increase is presumed in demand of energy by 2040. However, there will be more emphasis on renewal sources considering environmental protection, but fossil fuels (especially gas replacing major part of coal) will remain dominating although decreasing as source of electricity generation. The energy consumption is highly variable in different countries of the world, not necessarily proportional to the populations but also many other factors; economic development, lifestyle, and climate. The top ten high consuming countries in the descending order are China, USA, India, Russia, Japan, Canada, Germany, South Korea, and Brazil (Table 1). It is very clear that these ten countries swallow 66% of energy utilization of the world. Only China consumes 23.9% while USA takes 16.6%, thus these two countries share 40.5% of the word’s energy consumption. If India and Russia are added too, the energy dissipation of the four biggest countries rise to 51.5%, which means that the whole of the rest world consumes even a bit lesser (0.5%) than 50% (Table 1). The per capita consumption of electricity is also highly variable in different countries. The values range from 52921.73 KWh (Iceland) to 8.32 KWh (Liberia). This rate for GCC countries ranged from 5340 KWh to 17,610 KWh in 2010, compared to 3378 KWh and 2728 KWh, the respective means for the Middle East and the globe (IRENA, 2012). The countries ranking in the top ten list during 2015 are Iceland (52921.73), Norway (25018.59), Kuwait (18818.11), Bahrain (18491.19), UAE (18213.33), British Virgin Island (18035.13), Qatar (15784.42), Canada (14501.59), Finland (14328.50), and Sweden (12589.75). At the bottom of the list are Burundi, Sierra Leone, Guinea-Bissau, Chad, and Liberia in the descending order. The per capita consumptions of Saudi Arabia and Oman were 10248 and 5987 KWh, respectively while the other four countries of GCC have already been included in the top ten list above (CIA, 2019).
Дата Публикации: 06-01-22
All About Fire Safety Valves
Описание: All About Fire Safety Valves One of the more recent developments in industrial tools to prevent fire is the introduction of fire valve. These valves are designed to prevent a fire from spreading if the fuel valve gets damaged or causes a leakage. A valve is a device that adjusts, directs, or controls the flow of a fluid by opening, closing, or partially blocking various passageways. Valves are technically a type of fitting but are usually discussed separately. In an open valve, fluid flows from higher pressure to lower pressure. The simplest kind of valve is simply a freely hinged flap that drops to obstruct flow one way but is pushed open by fluid flowing the opposite way. This ancient valve is called a check valve, as it stops or "checks" the flow in one direction. Modern valves may regulate pressure or flow downstream and operate on sophisticated automation systems. Valves have industrial applications for controlling processes, residential uses such managing water flow to dish and clothes washers and taps in the home. They are found in almost every industrial process, including mining, water and sewage processing, power generation, food manufacturing, processing of oil, gas and petroleum, chemical and plastic manufacturing, and many other fields. Fire-safe valves are spring-loaded valves that are thermally actuated. In case of fire, they close automatically and stop the fuel flow. The fuel flow from the crankcase of the engine and the reserve oil supply gets hindered, thus minimizing the chances of leakage. Spring-loaded valves help with preventing the flow of fuel such as oil, gas, petrol, and other combustibles, and are useful and effective against any damage. The benefits of using fire landing valve in a system are the protection of human life, lower insurance rates, and the protection of equipment and the building. It is because of these benefits that the use of these valves is highly recommended and appreciated. These days, many companies offer an extensive range of fire-safety valves to provide protection even in high temperature and high-pressure conditions. How Fire Safety Valves Work A fire safety valve aims to keep ignitable fluids away from a flame. These fire gate valve close when exposed to heat, separating a flammable liquid from the heat source. They close in the midst of overheating of the pipeline, brought on by fire or similar events. The obligation to use fire safety valves is subject to any tenets, regulations, and laws concerning the unique methodology, plant, pipeline, or vessel. Fire-safe ball valves use a combination of a floating ball, graphoil seals, and metal-to-metal seating to provide tight shut-off while preventing external stem leakage. In normal working conditions, the ball rests against two seats, ensuring bubble-tight closure. When the valve is exposed to a temperature above the limits the seats can withstand (for example, +450°F), the seats become deformed and are subject to extrusion. When the seats have been completely destroyed, the ball in the valve will come to rest firmly against the end cap, producing a metal-to-metal closing. Stem seals, which have high temperature-resistant properties, further restrict leakage in conjunction with a blow-out-proof anti-static stem, so that the flammable fluid stays separate from the heat source that may ignite it. A fire-safe valve may also be made up of four main mechanisms: a spring pack, a trigger assembly, mounting hardware, and a fusible link. The components work in unison to close the valve should a fire be detected within a facility. The fusible link is the key part of the assembly. It keeps the valve open by maintaining tension on a spring pack through the trigger assembly. When a fire breaks out, the fusible link separates once it is heated to a certain high temperature, which releases the spring pack and allows it to close the valve. A fire-safety valve with fusible links has a primary drop-tight seat, usually made of TFE, along with a second seat made of metal for isolation in a fire. The secondary seat also has graphite seals for further protection. This means that the shut-off valves can be paired with any quarter-turn ball valve, butterfly valve, or fire ball valve. Summary This article presents an understanding of fire safety valves. For more information on related products, consult our other guides or visit the Thomas Supplier Discovery Platform to locate potential sources of supply or view details on specific products. The definition of a fire-safe valve has more than one answer since different standards exist for such valves. The major standards are presented in this article and their criteria discussed as an aid in specifying these devices. Fire-safety standards for equipment used in the chemical process industries (CPI) are critical however no single test for fire-safe valves has been developed that covers all of CPI. Since all fires are not alike, safety precautions should not all be the same for all situations. This article attempts to answer such questions as whether the refining industry's standards cover fire hazards posed by media and processes specific to the rest of the CPI and which criteria come closest to providing proper guidelines for choosing a fire-safe valve for non-oilrefining service. The effectiveness of fire air release valve has been investigated when offshore process equipment is exposed to a fire. Simulations of several typical offshore pressure vessels have been performed using the commercial software VessFire. The pressure vessels are exposed to a small jet fire, large jet fire, and a pool fire on both the wetted and unwetted part of the vessels. Rupture times of the vessels are calculated by comparing the pressure in the vessel with the tensile strength of the material. Rupture times are then compared for the vessels, with and without a PSV, in order to see the effect of the installed PSV. It is found that when a fire affects the unwetted part of a vessel, the PSV offers only minor or no additional protection. When a fire affects the wetted part of a vessel, the PSV relieve the inventory as designed. It is argued that PSVs provide insufficient fire protection for typical offshore fire scenarios and that Blowdown Valves and Passive Fire Protection should be considered as alternatives. In order to protect process equipment from a possible overpressure scenario a PSV is installed as a mechanical barrier. Often, when other credible over-pressure scenarios such as process upsets are ruled out, either due to the vessel in question being protected from over-pressure by upstream or downstream equipment, and/or the design of the vessel is to full pressure spec, the remaining credible scenario is a fire case. This is according to normal industry practice and according to code (API Standard 521, 2014, API Standard 14C, 2007). It is the authors’ experience that many vessels are equipped with a fire PSV as the main/only relief case. The main concern is that a pressure vessel exposed to a fire may cause a Boiling Liquid Expanding Vapor Explosion (BLEVE) upon rupture, leading to a significant escalation in consequences. The BLEVE scenario is relevant for vessels carrying significant components of light volatile liquid hydrocarbons such as separators and not for vessels only containing gas or non-volatile liquids. Standards such as API 521 (API Standard 521, 2014) (ISO 23251) and API 14C (API Standard 14C, 2007) (ISO 10418) discuss the requirement for PSVs for fire protection and how to size such PSVs. The use of fire PSVs, in accordance with API 521, has been developed for pool fires on onshore refineries. However, on offshore oil and gas installation a more likely fire scenario will often be that of a jet fire. According to API 521 fire PSVs do not offer proper protection against jet fire, but other measures such as shutting down the jet fire source and depressurizing process inventories should be considered the primary protection against a jet fire. Pool fire heat loads applied in API 521 for offshore applications have also been questioned (VESSFIRE, 2003). Even in the case of pool fire a fire PSV may not provide adequate protection in accordance with API 521 if the pool fire exposes the unwetted part of the pressure vessel. Despite this, fire PSVs are often installed on offshore oil and gas installations to protect even completely gas filled pressure vessels. Installing safety equipment such as a PSV that does not provide any or insignificant protections represent a significant lifecycle cost and it may also increase risk of operating the offshore installation as well as provide a false sense of security. The PSV will require testing, inspection and maintenance which will expose personnel to hazards, the PSV will be a source of potential leakage, and human errors in connection with the PSV can lead to increased risk of failure. In fact, there have been numerous examples in the offshore oil and gas industry where incidents and accidents have occurred in relation to use of PSVs. The best example, illustrating the risk associated with PSVs, is the Piper Alpha disaster where a PSV was taken out for maintenance together with a condensate pump without positive isolation. Experiments carried out by Birk et al. (2006), demonstrates that a pressure vessel, which is exposed to a flame on the unwetted part, will rupture before the pressure is high enough to trigger the PSV. As discussed by Dalzell and Chesterman (1997) safety systems should only be installed if they provide a safety benefit and not merely because it is recommended in standards or because it is the normal industry practice. Another issue with installing a fire PSV that cannot prevent rupture, is that the PSV may be regarded as a sufficient safety barrier in accordance with standards and best practice, when in fact, it provides no, or no significant, barrier. The purpose of this article is to investigate in which cases a fire PSV is expected to provide a safety benefit offshore by performing a case study with the state of the art software tool VessFire (VESSFIRE, 2003). Seven typical offshore pressure vessels are analyzed for three different fire scenarios: a large jet fire, a small jet fire and a pool fire. The simulations have been performed for the fire exposing both the wetted and unwetted part of vessels.
Дата Публикации: 06-01-22
Baseball Uniforms of the 20th Century
Описание: Baseball Uniforms of the 20th Century Since the subject matter of this research deals with the twentieth century, we will defer any discussion of nineteenth century precedents. Certainly, the history of baseball jersey is evolutionary and the uniforms of 1900 are a continuation of 1899 but the story of earlier uniforms is even more difficult to develop and we will reserve that information for future additional research. An important finding of such research will be establishing the starting point of use of separate uniforms at home and on the road, which was standard for all major league teams by 1900. FABRICS Uniform fabrics in 1900 were either 100% wool flannel or a blend of wool and cotton. Summer temperatures and humidity were no different than now and the idea of playing baseball weighted down with these heavy uniforms seems unthinkable today. But play they did, and with as much vigor and dash as the modern, more comfortably clothed players of the 1980's. The weight of these wool and cotton flannels was gradually reduced in half by the 1940's but the problems of durability and shrinkage had not improved much. The advent of synthetic fibers in the post-WWII era (NYLON, DACRON, ORLON) paved the way for improved blends. The most successful of these was the WOOL / ORLON blend in the sixties — seemingly the "ultimate" material for baseball shirt. But the double-knit fabrics introduced in the early seventies provided so many more attractive and practical features over flannel: lighter, cooler, more comfortable, more durable, etc. etc. Traditionalists insist that the tight-fitting stretchy double knit suits cannot compare with the well-tailored flannel look of the sixties, but the use of the flannel materials for sublimation hockey jersey is "history" — unless some new miracle fabric comes along that more clearly simulates flannel. FABRIC PATTERNS AND COLORS Home uniforms for all clubs at the turn of the century were white, while road uniforms were either gray or a darker hue. The material itself was heavy wool flannel which must have been insufferably warm in mid-summer. Pin striping in the fabric first appeared around 1907 — a fine, narrowly spaced line on the road grays that was barely visible from a distance. The Chicago Cubs were probably the first to use this pattern, but the Boston Nationals went a step further with a discernable green pin stripe on their 1907 road suits. The Brooklyn club was yet more daring with a fine blue cross-hatch pattern on their 07 road grays. This checked effect would be used later by the New York Giants and again by Brooklyn (with wider spacing) on several occasions. The wider spaced, more visible pin striping first appeared on several major league team uniforms in 1912. The finer striping on road uniforms was becoming common and by the mid-teens, half the teams were sporting the more distinct pin-stripes on their home uniforms. The Giants in 1916 provided the ultimate an almost plaid effect with a crossing of multiple fine lines of purple. A popular alternative to the gray-colored travelling suits in the 1900-1915 era was a solid dark blue or black material with white relief — often a negative image of their home whites. Although black and white photography may conceal earlier examples, the color TAN was introduced on the Dodger's 1937 road uniforms (to complement the Kelly Green trim). Charles 0. Finley's Kansas City A's in 1963 challenged the entire tradition of home / road colors with a stunning gold and green combination. By the 1970's, light blue was in common use in place of the gray color on road suits. CAP STYLES Several styles of cap design were worn in the first decade by major league clubs. The "pillbox" or Chicago style usually incorporated horizontal striping much like a layer cake and was a survivor of the 1890's. The so-called "Brooklyn" style had a higher, fuller rounded crown than the more common "Boston" style. The Boston style was the forerunner of future cap styles with a rounded close-fitting crown, more abbreviated than current styles and with the top button tilted more toward the front. Variations of the "cake box" crown resurfaced in later years — the A's of 1909-1915, the Giants in 1916 and the Pirates in modern times. The standard modern cap has changed very little in recent decades — slightly fuller crown and larger sun visor than its antecedents. SHOES Baseball pants, up to the TV age, were like Henry Ford's Model T: you could have any color you wanted as long as it was BLACK. The shoe height dropped from just below the ankle bone to a basic low-quarter style by 1910. The KC A's revolutionary white shoes in the sixties opened the door for color matching and hardly an all-black shoe can be found on today's major leaguers. JERSEYS AND UNDERSWEATERS Jerseys at the turn of the century were pretty much flannel pullover shirts with a standard fold-down collar and a buttoned or laced front. Even the sleeves were often full length with buttoned cuft and a left-breast pocket was common. It became fashionable with players later in the decade to wear the collar folded up and pinned at the throat. Undersweaters were becoming a part of the color scheme (some even had stripes) and elbow-length sleeves were worn to accent the sleeve colors. An unusual feature that provided a choice in sleeve length was the detachable sleeve — attached at the elbow with buttons. The first radical change in shirt design in the decade was provided by John McGraw's 1906 Giants when they introduced the collarless jersey with a lapel contour curiously indentical to that of later decades. The fold-down collar was definitely on its way out but its popular replacement was to be the short, stand-up cadet style — first worn by the Cubs in 1909. By 1912, most clubs adopted the cadet collar and some even sported the almost collarless V neck style, the next popular trend. Some of the 19th century features persisted into the decade of the teens: the Boston teams had a laced shirt front as late as 1911 and the Detroit Tigers briefly resurrected the fold-down collar during World War I. The shirt pocket had disappeared forever by 1915. The V neck collar style, with a brief tapered extension around the neck, was pretty much the unanimous standard during the twenties. Sleeve lengths varied during the decade. By the mid-thirties, the collar extension disappeared and sleeve lengths were nearly all half (or elbow) length. The first zipper front made its appearance on the all new Cubs uniforms of 1937 and became popular with many clubs for a decade or so. The most innovative jersey of its time " the sleeveless vest " was also in troduced by the Chicago Cubs in 1940. The blue undersweater most often used with the vest was also novel — 3 red stripes (to match the sox stripes) just below the elbow and sometimes a white crown across the shoulders. The vest survived for 3 seasons and resurfaced in the fifties and sixties with several clubs. The zipper was pretty much history by the sixties, except for an occasional curtain call — most recently by the Phillies. By the 1970's, the flannel fabrics were lighter and more comfortable with shorter sleeves, but the development of the revolutionary double-knit fabrics doomed the flannels forever. Many of the new-look jerseys were buttonless pullover styles, but the button front has remained popular — indeed current trends indicate a return to the traditional buttons by many clubs. TROUSERS AND BELTS Built-in protective padding was a standard part of ninteenth century American football jersey and this "quilting" survived on a few of the post-1900 uniforms. Separate sliding pads on the inside soon became the preferred choice. Belts were considerably wider and were furnished in a variety of colors and materials. Belt tunnels on the sides came into being after 1900 and are a standard feature even on many of today's double-knits. Piping down the sides of the trousers existed in the early 1900's, even before piping became a popular jersey trim feature. Considering the tailoring differences between the old, baggy flannels and the closer fitting double-knits of today, the basic "knickers" concept has really changed very little since 1900. STOCKINGS Stockings in 1900 were made of heavy wool and were of one-piece full-length (above the knee) construction. The foot covering part below the ankle bone was white or natural wool and often created the illusion of stirrups. The true stirrup stocking, separate from the "sanitary" foot stocking, first came into being about 1905. The popularity of striped or multi-tone stirrup stockings ebbed and flowed in cycles, becoming widely used around 1910 and less common by the late teens. Except for a few "candy-cane" varieties (particulary by the Giants, Cardinals & Washington), striping was quite minimal during the twenties and, in contrast, enjoyed a revival of sorts in the early thirties. As pant legs became lower and stirrups were stretched higher and higher over the following decades, the stockings became a neglected component in the overall appearance of the uniform. In fact, since the sanitary undersock has gained more and more visibility, its traditional white color, in some cases, has been abandoned for a distinct color to complement the new colored variety of shoes. TRIM COLORS AND GRAPHICS In the 1890's stocking colors were the principal device in distinguishing one team from another (hence the team names White Stockings, Red Stockings, Browns, etc.) and graphic displays identifying the home city were merely extra window dressing. In fact, some clubs after 1900 elected to wear plain unmarked jerseys and left their unique identification to their stocking colors and caps (i.e. the Chicago Nationals and St. Louis Americans). Although trim colors were abundant in uniform schemes, the selection was limited to BLACKS, DARK BLUES, MAROONS or REDS, & BROWNS and seldom in combinations (some exceptions: Pittsburgh's maroon & navy stockings, Detroit's black stockings with a red stripe). Lettering styles for the home city name were usually in plain block capital letters (from the manufacturer's standard stock) and the single letters or monograms were either a similar block style or a heavily ornamental Victorian or Old English type. John McGraw was quite unpredictable and often innovative in dictating the color schemes of his Giants. Once the team's N-Y monogram style was established (c. 1909), he stayed with it but he boldly flaunted color traditions by introducing VIOLET in 1913 as a trim color. The Cubs in 1916 added a second color red to dress up the navy blue trim and a wave of patriotism in the WWI years encouraged a more generous display of red, white and blue on some major league uniforms. In the case of many clubs, team nicknames were an unofficial invention of the press and changed constantly. On the other hand, clubs such as the Cardinals, Tigers and Athletics were universally identified by fans and team management alike. However, display of the nickname (or representative symbols of same) on the uniform were rare in the early decades of the century. The first instance of displaying a graphic symbol of the team nickname was the small red tiger on the black cap of the 1901 Detroits. When the Boston Americans decided to adopt the new nickname of RED SOX in 1908, they did so with an unusual graphic display, showing a red sock silhouette (with the word BOSTON inside) on their shirt fronts. The small cub figure inside the Chicago National "C" in 1908 would be the only other such embellishment of this type among NL teams in the 1900-1910 period. The first spelling out of the team's nickname on the jersey was on the Washington home shirts of 1905. Determined that they were no longer to be called the "Senators", their now official name "NATIONALS" was displayed in capital letters across the chest. Simpler and more established nicknames soon appeared. By 1910, the new cadet-style collar shirts placed a new emphasis on the front button lapel and it became fashionable to stack up the letters of the team name or city name in a vertical position. By the 1920's, display of the team name had become common (even the conservative Yankees did it for a time on their road uniforms). Oddly, the Philadelphia Athletics had never in their long history displayed so much as a letter P to identify the home city, yet they were the last of the original 16 major league franchises to spell out the full nickname ATHLETICS — in their final year (1954) in the City of Brotherly Love. The Detroit Tigers in 1930 established an important precedent by using a script lettering of DETROIT in place of the traditional capital letters. By the end of the decade, the idea of slanted script letters with an underline flourish was widely used. Also, a second trim color became the norm for many other major league teams in the thirties. As for graphic symbols, almost every club by this time had displayed some pictorial version of club identification at one time or another. Even the Athletics exploited their elephant symbol (whose origin is a story in itself) as early as 1905 on their team sweaters and later on the uniform jersey. Many of the team nicknames defy visual identification (Reds? Phillies? Nationals? Dodgers?) and thus escaped usage. Perhaps the St. Louis Cardinals have the most notable and familiar graphic presentation with their 2-birds-on-a-bat design which began in 1922 and, with few interruptions has persisted to this day. In the last years before numbers became standard on the backs of the shirts, the Detroit and Boston NL clubs boldly displayed a colorful tiger's head and Indian head profile respectively, on their backs. On rare occasions the entire team name (city and nickname) has been spelled out on th uniform. The Cubs in 1909 were the first with CHICAGO in vertical lettering down the buttor lapel and the CUBS emblem on the left breast. The last major league uniform to show the full team name was by the San Diego Padres in 1978. In recent decades, more imaginative lettering styles appeared — notably, the Indian with an unusual interpretation of American Indian-type calligraphy in the early seventies. Probably the most tasteful and attractive use of a modern type face is exemplified by the current BLUE JAYS uniform set. The proliferation of color TV coverage of major league baseball probably did more to invite the use of brighter and non-traditional uniform color schemes in the 1960's. The Athletics' gold and green ensembles started a color revolution that culminated in the bizarre "rainbow" jerseys introduced by the ASTROS in 1975. However, in midst of the color orgy, a handful of teams (i.e. the Yankees, Red Sox, Tigers) maintained a fairly consistent conservative image, hoIding steadfastly to the dictates of a long tradition Even the trends of the double-knit revolution (pullover jersey, beltless trousers) seem to be reverting to earlier styles (buttoned jersey and belted trousers). The popular practice of stretching the stirrups far up under the trouse legs also seems to be reversing itself and once again revealing the heretofore unseen striping on the outer socks. Among the expansion teams, the two Canadian entries have maintaned stable, consistent uniform designs. The other side of this coin is the San Diego franchise, which has at times changed its uniform designs almost annually in their nearly 2 decades of existence in the majors.
Дата Публикации: 06-01-22
exctma.com
Описание: exctma.com A conveyor system including Belt Conveyor System and Screw Conveyor System is a fast and efficient mechanical handling apparatus for automatically transporting loads and materials within an area. This system minimizes human error, lowers workplace risks and reduces labor costs — among other benefits. They are useful in helping to move bulky or heavy items from one point to another. A conveyor system may use a belt, wheels, rollers, or a chain to transport objects.Typically, conveyor systems consist of a belt stretched across two or more pulleys. The belt forms a closed loop around the pulleys so it can continually rotate. One pulley, known as the drive pulley, drives or tows the belt, moving items from one location to another. The most common conveyor system designs use a rotor to power the drive pulley and belt. The belt remains attached to the rotor through the friction between the two surfaces. For the belt to move effectively, both the drive pulley and idler must run in the same direction, either clockwise or counterclockwise. While conventional conveyor systems such as moving walkways and grocery store conveyors are straight, sometimes, the unit needs to turn to deliver the items to the proper location. For the turns, there are unique cone-shaped wheels or rotors which allow the belt to follow a bend or twist without getting tangled. The main purpose of a conveyor system is to move objects from one location to another. The design allows for movement of objects that are too heavy or too bulky for humans to carry by hand. Conveyor systems save time when transporting items from one location to another. As they can be inclined to span multiple levels, they make it simpler to move items up and down floors, a task that, when performed manually by humans, causes physical strain. Inclined belts can automatically unload material, eliminating the need for someone to be on the opposite end to receive pieces. You can probably imagine a large warehouse filled with conveyors using belts and rollers to move boxes and other heavy equipment, but this is just one of several types of conveyor systems. You’ll also find conveyor systems in airports, where they're used to transport luggage. Other examples include escalators and ski lifts. These apparatuses still use a belt or chain and pulleys to move heavy items from one point to another. And there are many different types of conveyors like Belt Conveyor, Pipe Conveyor, Corrugated Sidewall Belt Conveyor, Portable Belt Conveyor, Chain Conveyor and Screw Conveyor. Each type of conveyor serves a specific purpose. For example, a slat conveyor, made from slats or plates instead of a belt, is designed for moving heavy materials. The materials conveyed by a slat system are typically too large or heavy for traditional belt movement. An escalator is an example of a chain-driven conveyor system. Instead of having a pulley system that pulls items along, the chain conveyor uses a towing system that pulls the steps in an upward or downward motion. Ski lifts are an example of an overhead conveyor. These units use an electric track inclined to pull the chairs up or down the mountainside. Like an escalator, these systems use a chain-driven towing system. Also, the conveyor can't work along. The successful running of the conveyor requires some Belt Conveyor Components like Belt Conveyor Covers and Belt Conveyor Sway Switch.
Дата Публикации: 06-01-22
dmmccb.com
Описание: dmmccb.com A circuit breaker is an electrical safety device designed to protect an electrical circuit from damage caused by an overcurrent or short circuit. Its basic function is to interrupt current flow to protect equipment and to prevent the risk of fire. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect low-current circuits or individual household appliance, up to large switchgear designed to protect high voltage circuits feeding an entire city. The generic function of a circuit breaker, or fuse, as an automatic means of removing power from a faulty system is often abbreviated as OCPD (Over Current Protection Device). There are different types of Circuit Breaker like bAC Miniature Circuit Breaker, AC Earth Leakage Circuit Breaker, Air Circuit Breaker, Moulded Case Circuit Breaker and Earth Leakage Moulded Case Circuit Breaker. All circuit breaker systems have common features in their operation, but details vary substantially depending on the voltage class, current rating and type of the circuit breaker. The circuit breaker must first detect a fault condition. In small mains and low voltage circuit breakers, this is usually done within the device itself. Typically, the heating or magnetic effects of electric current are employed. Circuit breakers for large currents or high voltages are usually arranged with protective relay pilot devices to sense a fault condition and to operate the opening mechanism. These typically require a separate power source, such as a battery, although some high-voltage circuit breakers are self-contained with current transformers, protective relays, and an internal control power source. Once a fault is detected, the circuit breaker contacts must open to interrupt the circuit; this is commonly done using mechanically stored energy contained within the breaker, such as a spring or compressed air to separate the contacts. Circuit breakers may also use the higher current caused by the fault to separate the contacts, such as thermal expansion or a magnetic field. Small circuit breakers typically have a manual control lever to switch off the load or reset a tripped breaker, while larger units use solenoids to trip the mechanism, and electric motors to restore energy to the springs. The circuit breaker contacts must carry the load current without excessive heating, and must also withstand the heat of the arc produced when interrupting (opening) the circuit. Contacts are made of copper or copper alloys, silver alloys and other highly conductive materials. Service life of the contacts is limited by the erosion of contact material due to arcing while interrupting the current. Miniature and molded-case circuit breakers are usually discarded when the contacts have worn, but power circuit breakers and high-voltage circuit breakers have replaceable contacts. Unlike circuit breaker, a contactor or switch is an electrically-controlled switch used for switching an electrical power circuit. A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24-volt coil electromagnet controlling a 230-volt motor switch. Without general-purpose relays, contactors are designed to be directly connected to high-current load devices. Relays tend to be of lower capacity and are usually designed for both normally closed and normally open applications. Devices switching more than 15 amperes or in circuits rated more than a few kilowatts are usually called contactors. Apart from optional auxiliary low-current contacts, contactors are almost exclusively fitted with normally open ("form A") contacts. Unlike relays, contactors are designed with features to control and suppress the arc produced when interrupting heavy motor currents. Contactors come in many forms with varying capacities and features. Unlike a circuit breaker, a contactor is not intended to interrupt a short circuit current. Contactors range from those having a breaking current of several amperes to thousands of amperes and 24 V DC to many kilovolts. The physical size of contactors ranges from a device small enough to pick up with one hand, to large devices approximately a meter (yard) on a side. It also has many different types like Knife Switch, Disconnector Switch, CJ20 Contactor, CJ19 Contactor, etc. Contactors are used to control electric motors, lighting, heating, capacitor banks, thermal evaporators, and other electrical loads.
Дата Публикации: 06-01-22
aipuaircompressor.com
Описание: aipuaircompressor.com What are air compressors? Technically, air compressors are machines that convert one form of energy into another form, which can then be stored and used at a later point in time. But neither that brief explanation, nor the more detailed description below do this invention and its profound impact on our lives. That is why it is "The machines that have changed our world more than almost any other invention.” What may sound like hyperbole is actually a very accurate description of the impact air compressors have had on our society – and especially the industrial sector. In less than 150 years since Austrian engineer Viktor Popp built the first compressor plant, compressed air has become so indispensable that it is now referred to as the “fourth utility” along with electricity, water and gas.The numbers back up this bold statement. It is estimated that 10% of all electricity consumed by the manufacturing industry is used for compressed air. To understand the importance of compressed air and the compressors that generate it, let's first take a closer look at the physics of it. Compressed air is simply regular air that is forced into a much smaller space. When this happens, its molecules speed up and so-called "kinetic energy" is created. That kinetic energy can either be used right away or it can be stored and released later. One of the reasons compressed air has become so indispensable is its versatility. Just about every industry relies on compressed air in some form – from manufacturing plants to cars, s With so many different Compressor Applications such as Oxygen and Nitrogen Generator, it also makes sense that there are many different types of air compressors. After all, the small and quiet compressor that powers a dentist’s drill should not be the same as the industrial compressor that keeps an entire manufacturing plant going. However, the many options also make it difficult for laypersons to find the compressor that is right for them. To make things easier, here is an overview of different compressor types and technologies. First, let’s take a look at how compressors work. There are two main compression technologies. Positive displacement compressors have a cavity that is filled with regular air (or another gas at atmospheric pressure). That cavity then becomes smaller, which means the same amount of air has to fit into a smaller space and its pressure and kinetic energy increases. Dynamic compressors achieve the required rise in pressure by accelerating the air (or gas) with an impeller and then slowing it down in a diffuser. Positive displacement compressors are much more frequently-used and they feature different technologies to displace the air. Piston compressors use a reciprocating motion, rotary screw compressors a single rotor and the more seldomly utilized scroll compressors feature a double rotor. Each of them has their different benefits and uses. Piston compressors, for example, are fairly simple machines that are inexpensive to buy. They are often the right solution for operations with a low compressed air demand. Rotary screw compressors are more advanced and offer a low total cost of ownership. They are more energy efficient and can produce a lot more compressed air. Dynamic compressors, on the other hand, are primarily used for operations and applications that require very high volumes of air. There are also some Compressor Accessories like Air Compressor Air End required for the normal running of the machine.
Дата Публикации: 06-01-22