Reliability, of supply

Therefore, every effort must be placed on ensuring the quality, consistency, and reliability of supply of the incoming raw materials and components. Since this chapter is about the need for consistent, high-quality elastomeric compound, emphasis will be placed on incoming raw materials, compound mixing, extrusion (where appropriate), and molding. 

Raw Materials Raw materials have a significant impact on the manufacturing process. Issues such as availability and reliability of supply, reactivity, toxicity, handling, and storage have to be considered. Cost is another factor to take into account. Often, trade-offs between costs, manufacturing processes, and yields are considered. 

Today, the choice of feedstock for chemicals production depends on complex technical, economic, environmental, and political factors. Clearly, not all chemicals are suitable for production from coal with current technology. Some factors to be considered in the evaluation of the appropriate feedstock for a particular chemical product are (1) the relationship between the carbon/hydrogen ratio in the chemical product and the feedstock, (2) the delivered cost of alternative raw materials, (3) capital costs, (4) environmental protection, and (5) the reliability of supply. Recently, except for special situations, such as that for Sasol in South Africa, the manufacture of chemicals from coal at coal prices relative to the prices of petroleum and natural gas has not been attractive economically. 

Raw materials availability. The source of raw materials is one of the most important factors influencing the selection of a plant site. This is particularly true if large volumes of raw materials are consumed, because location near the raw-materials source permits considerable reduction in transportation and storage charges. Attention should be given to the purchased price of the raw materials, distance from the source of supply, freight or transportation expenses, availability and reliability of supply, purity of the raw materials, and storage requirements. 

In the interests of economic support, quality control and reliability of supply, these technologies are more likely to succeed when provided by commercial concerns rather than rural communities. 

Procurement departments have the twin aims of driving down costs while ensuring quality and reliability of supply. In order to do this, they need to balance three specific elements of its mix of needs supplier relationships, material nature and material availability. 

Physical distance is not the only controlling factor in the source of raw materials, for purchase price and buying expense, base point pricing, reserve stock, and reliability of supply are also determinants. 

Excess power generated (more than own requirement) The additional power can be exported to external grid. This is not easy, however, due to conditions laid down by grid authorities for quantum of power and reliability of supply. 

Compare cost of material from different places with the transport cost. Check reliability of supply if procurement is to be done from long distance. 

The basic assmnption for the operation of distribution systems of medium voltage (MV) and also of other voltage levels is to ensure rehable, safe and high-quahty supplies of electrical energy. Investments into modem equipment for the automation of operation of distribution systems are one of important factors that fundamentally influence the reliability of supplies of electrical energy. Here, it is necessary to use as a basis the duration and the number of failure states, planned actions, repairs in the framework of controlled mainteiiance plan and also building of new facilities. 

The evaluation of the reliability of supplies to the nodes is, as a matter of fact, the main reason why the calculation is performed. However, it is not as simple as in... 

Ink is like the life-blood of the inkjet printer, and thus also the business. Business calculations averaging costs of ink per meter should include time for refilling reservoirs, storage requirements, and reliability of supply. Consistency is key there must be consistency of the ink, coloration, maintenance of the delivery system through the printer, and consistent management to maintain the printing, quality, and ultimately the business. Ink is discussed in more detail in Chapter 7 of this book. 

Fuel cell systems must be able to offer reliability of supply equal to centralized power grids they should have an operational lifetime equivalent to existing domestic and commercial boilers and generators and they need to be competitive in terms of cost of delivered power and heat (and cooling where appUcable). Stationary fuel cell systems have made steady progress toward reliability and... 

The main function of the power system is to provide electrical energy to the customers as economically as possible with an acceptable degree of continuity and quality, known as reliability. The two constraints of economics and reliability are competitive since increased reliability of supply generally requires increased capital investment. These two constraints are balanced in many different ways in different countries and by different utilities, though generally they are all based on various sets of deterministic criteria. 

Helseth A. 2008. Modelling Reliability of Supply and Infrastructural Dependency in Energy Distribution Systems Doctoral theses at NTNU 1-72. 

Numerous studies on the problems of reliability of supply chains (Ball 1979, Barnes et al. 2003, Brzezihski 2006), treat primarily on the reduction of system performance and load changes in... 

Another approach in terms of reliability of supply chains is a Fault Trees Analysis (FTA) (1990), which is probabilistic approach to safety, reliability, and risk analysis. Traditional fault trees contain Boolean gates to represent how component failures combine to produce system failures. These fault trees are now called static. Dugan et al. (1992, 1993) in their papers presented Dynamic Fault Trees (DFTs). They suggested that Gates of DFTs can express the following features ... 

Another approach was proposed by Bobyr et al. (2008). Authors in their work in contrast to the analytic approaches they used Monte Carlo simulation. However, Monte Carlo simulation is time-consuming because of the intensive computations. This is because an extremely large number of simulated samples may be needed to estimate the reliability parameters at a high level of confidence In summary, the available literature for the study on the reliability of supply chains can be classified according to various criteria, such as ... 

In a master s thesis carried out by Arne Brufladt Svendsen (Svendsen, 2002), thesis advisor Torris Digernes discovered a method suitable for building large Markov models. A central clue in the calculation was the Kronecker matrix operators, (Sasty, 1999). The method was tested by Svendsen in his thesis and found to be very efficient for reliability analysis of power systems. Since then, various R D projects concerning offline calculations of reliability of supply in complex meshed power grids have been carried out. 

The most important tools for power system operators are power flow calculations, dynamic analyses etc. To analyze the reliability of supply, additional tools are needed. 

The reliability of supply process mainly encompasses (Nowakowski, Werbihska 2007) ... 

Mixemat is a small raw materials supplier that has limited capacity but charges only 0.90 for a unit s worth of raw materials. Its reliability of supply, however, is in question. Mixemat does not have enough capacity to supply all its customers all the time. This means that orders to Mixemat are not guaranteed. In a year of high demand for raw materials, Mixemat will have 90,000 units available for Alphacap. In low-demand years, all product will be dehvered. 

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