Materials utilization factor

Manufacturing efficiency embodies a wide variety of topics far beyond the scope of this book. However, a materials utilization factor will be defined and characterized for composite materials and metals as a... 

In contrast, with composite materials, the materials utilization factor is rarely higher than 1.2 to 1.3. That is, only a maximum of 20-30% of the material is wasted with composite structures. Whereas obviously with a materials utilization factor for some metal parts of 15-25, the waste is 1500-2500% Those are not individually typical numbers, but are the worst cases in both situations, i.e., for metals and composite materiais. For metals, there are many, many operations for which the waste factor is very iow. And for composite materials there are also many situations where the waste factor is much lower than 20-30%. The point is that the worst-case situations are totaliy different for these two kinds of materials based on the way objects are inherently created with the two different types of materials. Composite materials are built up until the limits of the desired geometry are reached. At that point, the layup operation simpiy ceases. Composite materials and structures are fabricated in as ciose to the final configuration as possible, i.e., so-calied near-net shape. 

Figure 8. The experimental data and computed curve of the active material utilization factor...

Figure 8 provides a comparison of theoretically computed vs experimental dependences of the active material utilization factor for the investigated electrode. Analytical equations (24) and (25) were used to calculate polarization as a function of the oxidation state, and to calculate the limiting value of the oxidation state as the function of the discharge current (see Figures 7 and 8). 

The expression for the active material utilization factor shows that in the process considered, it is impossible to achieve full utilization of the active reagents in the galvanostatic mode. 

The mechanical support by the tube allows the use of fairly light active material. This means high porosity and a high utilization factor. 

Cost estimate for the Carlo Environmental Technologies, Inc., MTTD technology range from 30 to 69 per ton of soil or other material treated. Factors that influence costs are characteristics of the soil (most important) utility and fuel rates, and moisture content of the soil. The initial and target contaminant concentrations also affect costs (D101871, p. 28). 

Note that these calculations do not take into account such practical factors as the cost of the chemicals required, fraction of reactants not utilized, or nonreactive structural materials. These factors and others add to the cost of the batteries. 

Further advantages are the higher degree of material utilization and the large material stock, which is raised by a factor of 4 compared with planar targets. Both factors enable long-term operation (up to 2 weeks uninterrupted) without maintenance, while planar cathodes have to be maintained each week. 

The raw materials, utilities, and by-products were changed directly by the ratio of plant capacity. The hydrogen price was calculated using the same procedure as in the base case. Variations between the 0.6 and 0.7 power factor have only a small effect on hydrogen price. The assumption of many modules for electrolysis suggests a higher exponent. 

The basic equations are next presented. Eq.(l) is the mass balance equation for each echelon / and material s. The design decisions are modeled through Eqns.(2)-(3). Eq.(4) forces the production to be within installed capacity and a minimum utilization factor. Eqs.(5)-(6) force materials flow from suppliers and to markets to be lower than an upper bound given by their capacity limitations. 

Finally, the conversion of the primary metal into the product and the form which are actually utilized in the battery system should be considered. For example, the electrode materials in lead acid batteries are normally cast lead or lead-alloy grids. The materials utilized in NiCd batteries are cadmium oxide and high surface area nickel foams or meshes. Technically, all of these factors should be considered to produce a detailed life cycle analysis. However, again, these differences are generally quite small compared to the principal variables - composition, performance and spent battery disposal option. 

Another reason, which affects the utilization factor, is the structure of the carbon particles themselves. Rao et al. [17] have demonstrated that the catalyst utilization factor may vary significantly depending on the porosity of carbon materials. They have prepared a series of Pt-Ru (1 1) catalysts supported on carbon materials from the Sibunit family with grossly different BET surface areas, ranging from 20 to 400 m /g, which were utilized as the anode catalysts in liquid-fed DMFC. To be able to distinguish between the influence on cell performance of the metal dispersion and the carbon support porosity, the metal dispersion was kept constant and close to 0.3. It was demonstrated that the catalyst utiUzation factor reached 100% for low-surface-area supports but dropped down to 10% for the high-surface-area Sibunit carbon. As a result, in methanol electrooxidation, both the mass activity (Ag Ru) and specific activity increased with a... 

The cross sections for neutron capture increase for all atoms for thermal energy neutrons. As a result, even though low cross section materials are used some neutrons are captured by the structural and moderator materials. The probability for the non-capture of thermal neutrons in this fashion is signified by/, the thermal utilization factor, which in our case can be assumed to be 0.9. Thus of the original N neutrons 112 thermal neutrons remain in the second generation to cause fission in the nuclear fuel. 

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