Weight-cost ratio

In many cases, a single parameter determines the costs of a product so significantly that it can be used for the total evaluation or, as already described above, at least for parts of a product. It can be referred back to a weight-cost ratio in many sub-areas of the mold calculation. In some cases, weight-cost ratios can be used for the evaluation of the entire mold. A similar procedure is shown in Figure 5.6. The effective bounding volume of the component was chosen as the reference value for determining costs for aluminum prototype molds. 

Over the last decade, the poor economics of new polymer and copolymer production and the need for new materials whose performance/ cost ratios can be closely matched to specific applications have forced polymer researchers to seriously consider purely physical polymer blend systems. This approach has been comparatively slow to develop, however, because most physical blends of different high molecular weight polymers prove to be immiscible. That is, when mixed together, the blend components are likely to separate into phases containing predominantly their own kind. This characteristic, combined with the often low physical attraction forces across the immiscible phase boundaries, usually causes immiscible blend systems to have poorer mechanical properties than could be achieved by the copolymerization route. Despite this difficulty a number of physical blend systems have been commercialized, and some of these are discussed in a later section. Also, the level of technical activity in the physical blend area remains high, as indicated by the number of reviews published recently (1-10). 

The type of Petri net model used in this research is Place Weighted Petri net. Places represent equipment, transitions show starting and finishing of operations and tokens are raw material, semi-finished and finished products. The weights on places indicate Safety-Cost Ratios for equipment. 

The first products were made of 4 to 6% active, a fragrance, and a viscosity modifier [5], The dispersions of cationic actives indeed remain easily pourable as far as their concentration does not exceed 7% by weight since the softening efficacy levels off at concentrations above 6%, this was not a concern. In the mid-1970s improved softening systems made of two actives appeared on the market. They were still based on the same quaternaries, but synergistically combined with other fatty materials called co-softeners to enhance their performance/cost ratio. 

However, the molecular weights of these polymers at 1 x 10 (approx.) are too low to produce a reasonable viscosity/cost ratio of polymer solution in the FOR application. 

Compared with computers and even books, groceries have a low value-to-weight/volume ratio. For example, paper towels and bathroom tissues have very low value but occupy a lot of space in a truck. Thus, transportation costs are a significant fraction of the cost incurred by online grocers. This makes it difficult for an online grocer to compete with a supermarket on prices. 

Solvay s Amodel PPA resin features an excellent stil3iiess-to-cost ratio and a high strength-to-weight ratio, both of which are superior relative to PBT, PPS, PEI, PET and PA 6,6. Its thermal performance is exceeded only by polyetheretherketone (PEEK) and some LCPs its warpage and dimensional stability match PPS. Amodel resin has lower moisture absorption than PA 6,6, and its broad chemical resistance is exceeded only by a handful of more costly speciality polymers. 

The design selection procedure suggested here is to list candidate materials in material comparison tables, and list relative size ratios, relative cost ratios, relative weight ratios, and so on, in these tables, and then to select the materials based on these one of the relative ratios, typically cost. 

A stream-specific cost-weighting factor 4)j to apply to the h value of a special stream j can now he defined. This is the ratio of weighted to actual stream h values ... 

Solar cells have been used extensively and successfully to power sateUites in space since the late 1950s, where their high power-to-weight ratio and demonstrated rehabiUty are especially desirable characteristics. On earth, where electrical systems typically provide large amounts of power at reasonable costs, three principal technical limitations have thus far impeded the widespread use of photovoltaic products solar cells are expensive, sunlight has a relatively low power density, and commercially available solar cells convert sunlight to electricity with limited efficiency. Clearly, terrestrial solar cells must be reasonably efficient, affordable, and durable. International efforts are dedicated to obtaining such devices, and a number of these activities have been reviewed (1). 

A more economical route to MQ resin uses low cost sodium sihcate and trimethylchlorosilane as inputs (eq. 35) (395). The sodium sihcate process is initiated by acidifying an aqueous sodium sihcate solution to a pH of 2. The resulting hydrosol quickly builds molecular weight. The rate of this increase is moderated by the addition of an alcohol such as 2-propanol. The hydrosol is subsequentiy silylated by the addition of trimethylchlorosilane. This process, which is kinetically sensitive and limited to synthesizing M/Q ratios of 1 or less, is preferred when MQ resins having high (>1%) OH content are required (395). 

Synthetic polymers have become extremely important as materials over the past 50 years and have replaced other materials because they possess high strength-to-weight ratios, easy processabiUty, and other desirable features. Used in appHcations previously dominated by metals, ceramics, and natural fibers, polymers make up much of the sales in the automotive, durables, and clothing markets. In these appHcations, polymers possess desired attributes, often at a much lower cost than the materials they replace. The emphasis in research has shifted from developing new synthetic macromolecules toward preparation of cost-effective multicomponent systems (ie, copolymers, polymer blends, and composites) rather than preparation of new and frequendy more expensive homopolymers. These multicomponent systems can be "tuned" to achieve the desired properties (within limits, of course) much easier than through the total synthesis of new macromolecules. 

Cost Indices The value of money will change because of inflation and deflation. Hence cost data can be accurate only at the time when they are obtained and soon go out of date. Data from cost records of equipment and projects purchased in the past may be converted to present-day values by means of a cost index. The present cost of the item is found by multiplying the historical cost by the ratio of the present cost index divided oy the index applicable at the previous date. Ideally each cost item affected by inflation should be forecast separately. Labor costs, construction costs, raw-materials and energy prices, and product prices all change at different rates. Composite indices are derived by adding weighted fractions of the component indices. Most cost indices represent national averages, and local values may differ considerably. 

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