There is a very limited domestic capacity to make these essential medicine ingredients; the U.S. manufacturing base to make them has drastically eroded over the last several decades, and most of the supply now comes from abroad. For many materials, there is a single, foreign source of supply.
Approximately 50 per cent of plastics are used for single-use disposable applications, such as packaging, agricultural films and disposable consumer items, between 20 and 25% for long-term infrastructure such as pipes, cable coatings and structural materials, and the remainder for durable consumer applications with intermediate lifespan, such as in electronic goods, furniture, vehicles, etc. Post-consumer plastic waste generation across the European Union (EU) was 24.6 million tonnes in 2007 (PlasticsEurope 2008b). Table 1 presents a breakdown of plastics consumption in the UK during the year 2000, and contributions to waste generation (Waste Watch 2003). This confirms that packaging is the main source of waste plastics, but it is clear that other sources such as waste electronic and electrical equipment (WEEE) and end-of-life vehicles (ELV) are becoming significant sources of waste plastics.
manufacturing with materials edwards pdf 12
Recycling is clearly a waste-management strategy, but it can also be seen as one current example of implementing the concept of industrial ecology, whereas in a natural ecosystem there are no wastes but only products (Frosch & Gallopoulos 1989; McDonough & Braungart 2002). Recycling of plastics is one method for reducing environmental impact and resource depletion. Fundamentally, high levels of recycling, as with reduction in use, reuse and repair or re-manufacturing can allow for a given level of product service with lower material inputs than would otherwise be required. Recycling can therefore decrease energy and material usage per unit of output and so yield improved eco-efficiency (WBCSD 2000). Although, it should be noted that the ability to maintain whatever residual level of material input, plus the energy inputs and the effects of external impacts on ecosystems will decide the ultimate sustainability of the overall system.
Broadly speaking, waste plastics are recovered when they are diverted from landfills or littering. Plastic packaging is particularly noticeable as litter because of the lightweight nature of both flexible and rigid plastics. The amount of material going into the waste-management system can, in the first case, be reduced by actions that decrease the use of materials in products (e.g. substitution of heavy packaging formats with lighter ones, or downgauging of packaging). Designing products to enable reusing, repairing or re-manufacturing will result in fewer products entering the waste stream.
It is possible in theory to closed-loop recycle most thermoplastics, however, plastic packaging frequently uses a wide variety of different polymers and other materials such as metals, paper, pigments, inks and adhesives that increases the difficulty. Closed-loop recycling is most practical when the polymer constituent can be (i) effectively separated from sources of contamination and (ii) stabilized against degradation during reprocessing and subsequent use. Ideally, the plastic waste stream for reprocessing would also consist of a narrow range of polymer grades to reduce the difficulty of replacing virgin resin directly. For example, all PET bottles are made from similar grades of PET suitable for both the bottle manufacturing process and reprocessing to polyester fibre, while HDPE used for blow moulding bottles is less-suited to injection moulding applications. As a result, the only parts of the post-consumer plastic waste stream that have routinely been recycled in a strictly closed-loop fashion are clear PET bottles and recently in the UK, HDPE milk bottles. Pre-consumer plastic waste such as industrial packaging is currently recycled to a greater extent than post-consumer packaging, as it is relatively pure and available from a smaller number of sources of relatively higher volume. The volumes of post-consumer waste are, however, up to five times larger than those generated in commerce and industry (Patel et al. 2000) and so in order to achieve high overall recycling rates, post-consumer as well as post-industrial waste need to be collected and recycled.
Various methods exist for flake-sorting, but traditional PET-sorting systems are predominantly restricted to separating; (i) coloured flakes from clear PET flakes and (ii) materials with different physical properties such as density from PET. New approaches such as laser-sorting systems can be used to remove other impurities such as silicones and nylon.
A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.[2]
Cement materials can be classified into two distinct categories: hydraulic cements and non-hydraulic cements according to their respective setting and hardening mechanisms. Hydraulic cement setting and hardening involves hydration reactions and therefore requires water, while non-hydraulic cements only react with a gas and can directly set under air.
Portland cement, a form of hydraulic cement, is by far the most common type of cement in general use around the world. This cement is made by heating limestone (calcium carbonate) with other materials (such as clay) to 1,450 C (2,640 F) in a kiln, in a process known as calcination that liberates a molecule of carbon dioxide from the calcium carbonate to form calcium oxide, or quicklime, which then chemically combines with the other materials in the mix to form calcium silicates and other cementitious compounds. The resulting hard substance, called 'clinker', is then ground with a small amount of gypsum (.mw-parser-output .template-chem2-sudisplay:inline-block;font-size:80%;line-height:1;vertical-align:-0.35em.mw-parser-output .template-chem2-su>spandisplay:block;text-align:left.mw-parser-output sub.template-chem2-subfont-size:80%;vertical-align:-0.35em.mw-parser-output sup.template-chem2-supfont-size:80%;vertical-align:0.65emCaSO42H2O) into a powder to make ordinary Portland cement, the most commonly used type of cement (often referred to as OPC).Portland cement is a basic ingredient of concrete, mortar, and most non-specialty grout. The most common use for Portland cement is to make concrete. Portland cement may be grey or white.
The EU cement industry already uses more than 40% fuels derived from waste and biomass in supplying the thermal energy to the grey clinker making process. Although the choice for this so-called alternative fuels (AF) is typically cost driven, other factors are becoming more important. Use of alternative fuels provides benefits for both society and the company: CO2-emissions are lower than with fossil fuels, waste can be co-processed in an efficient and sustainable manner and the demand for certain virgin materials can be reduced. Yet there are large differences in the share of alternative fuels used between the European Union (EU) member states. The societal benefits could be improved if more member states increase their alternative fuels share. The Ecofys study[79] assessed the barriers and opportunities for further uptake of alternative fuels in 14 EU member states. The Ecofys study found that local factors constrain the market potential to a much larger extent than the technical and economic feasibility of the cement industry itself.
New manufacturing processes for producing ecological cement are being researched with the goal to reduce, or even eliminate, the production and release of damaging pollutants and greenhouse gasses, particularly CO2.[80]
A team at the University of Edinburgh has developed the 'DUPE' process based on the microbial activity of Sporosarcina pasteurii, a bacterium precipitating calcium carbonate, which, when mixed with sand and urine, can produce mortar blocks with a compressive strength 70% of that of conventional construction materials.[82]
Managing the shop floor, inventory, operations and scheduling are some of the keys to ensuring a manufacturing business runs smoothly. As manufacturing and supply chains scale to meet larger global needs, real-time data and software systems allow manufacturers to automate processes and make smart data-driven decisions. Two commonly implemented software systems are ERP (enterprise resource planning) and MRP (material requirements planning). Learn the differences and benefits of each software system, when your business may need an ERP or MRP system, and see how they can work seamlessly with one another to help streamline your business.
First, what does MRP stand for? In the manufacturing world, the acronym refers to Material Requirements Planning software systems. These solutions are especially helpful within the manufacturing industry because their primary purpose is to identify and measure what production materials are needed and when. This enables manufacturers to avoid loss of productivity due to downtime. Even companies whose primary functions lie outside of manufacturing still find MRP systems valuable for their production planning. This software helps production planners forecast and order the appropriate materials and keep appropriate levels of inventory.
With customization introducing so many new moving parts, keeping manufacturing operations running smoothly became critical. From planning to forecasting to spending, every aspect of manufacturing needs to perform in alignment to create the desired results without waste. Enterprise Resource Planning (ERP) systems were designed for this need.
The primary difference between ERP and MRP is that ERP systems help to plan and automate a variety of back-office business functions, whereas MRP systems focus on materials management. ERP directly touches accounting, manufacturing, supply chain, customer management, quality, processes and planning. MRP, however, has a more narrow scope of ordering and planning for manufacturing materials. For that reason, users of each system will be different. People from a variety of departments may use ERP software, but those with a tie to manufacturing operations may use MRP tools. 2ff7e9595c
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