Economics simple interest

A pipeline of 100 mm outside diameter, carrying steam at 420 K, is to be insulated with a lagging material which costs 10/m3 and which has a thermal conductivity of 0.1 W/m K. The ambient temperature may be taken as 285 K, and the coefficient of heat transfer from the outside of the lagging to the surroundings as 10 W/m2 K. If the value of heat energy is 7.5 x 10 4 /MJ and the capital cost of the lagging is to be depreciated over 5 years with an effective simple interest rate of 10 per cent per annum based on the initial investment, what is the economic thickness of the lagging ... 

Convection heat transfer is dependent largely on the relative velocity between the warm gas and the drying surface. Interest in pulse combustion heat sources anticipates that high frequency reversals of gas flow direction relative to wet material in dispersed-particle dryers can maintain higher gas velocities around the particles for longer periods than possible ia simple cocurrent dryers. This technique is thus expected to enhance heat- and mass-transfer performance. This is apart from the concept that mechanical stresses iaduced ia material by rapid directional reversals of gas flow promote particle deagglomeration, dispersion, and Hquid stream breakup iato fine droplets. Commercial appHcations are needed to confirm the economic value of pulse combustion for drying. 

If the fractional inflation rate is a fractional interest rate on a loan can be corrected to an effective rate of interest by Eq. (9-116) with ii substituted for (DCFRR). The effect of various amounts of loan, borrowed at various interest rates ii, on the net present value of a particular, fairly simple project is shown in Fig. 9-37. Thus, if 25,000 were borrowed at an interest rate of 15 percent for the project, the (NPV) would be about 43,000 at a zero inflation rate. But if the inflation for goods and services i, is 10 percent, the effective interest rate for that loan can be calculated from Eq. (9-116) to be only 4.55 percent. It is seen from Fig. 9-37 that this increases the (NPV) of the project to 48,000. This confirms the economic advantage of borrowing at a fixed interest rate in a time of general inflation. 

The early 1980s saw considerable interest in a new form of silicone materials, namely the liquid silicone mbbers. These may be considered as a development from the addition-cured RTV silicone rubbers but with a better pot life and improved physical properties, including heat stability similar to that of conventional peroxide-cured elastomers. The ability to process such liquid raw materials leads to a number of economic benefits such as lower production costs, increased ouput and reduced capital investment compared with more conventional rubbers. Liquid silicone rubbers are low-viscosity materials which range from a flow consistency to a paste consistency. They are usually supplied as a two-pack system which requires simple blending before use. The materials cure rapidly above 110°C and when injection moulded at high temperatures (200-250°C) cure times as low as a few seconds are possible for small parts. Because of the rapid mould filling, scorch is rarely a problem and, furthermore, post-curing is usually unnecessary. 

With the discovery of the crowns and related species, it was inevitable that a search would begin for simpler and simpler relatives which might be useful in similar applications. Perhaps these compounds would be easier and more economical to prepare and ultimately, of course, better in one respect or another than the molecules which inspired the research. In particular, the collateral developments of crown ether chemistry and phase transfer catalysis fostered an interest in utilizing the readily available polyethylene glycol mono- or dimethyl ethers as catalysts for such reactions. Although there is considerable literature in this area, much of it relates to the use of simple polyethylene glycols in phase transfer processes. Since our main concern in this monograph is with novel structures, we will discuss these simple examples further only briefly, below. 

The list of elements and their species listed above is not exhaustive. It is limited to the relatively simple compounds that have been determined by an important number of laboratories specializing in speciation analysis. Considering the economic importance of the results, time has come to invest in adequate CRMs. There is a steadily increasing interest in trace element species in food and in the gastrointestinal tract where the chemical form is the determinant factor for their bioavailability (Crews 1998). In clinical chemistry the relevance of trace elements will only be fully elucidated when the species and transformation of species in the living system have been measured (ComeUs 1996 Cornelis et al. 1998). Ultimately there will be a need for adequate RMs certified for the trace element species bound to large molecules, such as proteins. 

The advances made in enzymatic hydrolysis of cellulosic materials (14) are also of interest. This technology involves only moderate temperature processes in simple equipment which promises to be of significantly lower capital cost than the pressure equipment associated with conventional acid wood hydrolysis processes. All of these considerations combined to lead us to study processes for ethanol production from wood, especially in an effort to obtain data for material and energy balances, and possibly for the economics. 

Any experimenter is usually interested in obtaining an optimal response (a nominal value, a maximum or a minimum response) which is related directly to changes in the levels of the factors, but he/she needs also to guarantee a constant quality and, as a consequence, a minimum variability in the response. The main objective is then to control, although partially, the noise factors and obtain a system which is insensitive robust to them. In such a way, we can discard the noise factors in future studies. In short, a robustness design identifies the levels of the experimental factors that reduce the effect of the noise factors and consequently minimise the variability in the response in a simple and economical way. 

Remark 2 An important consequence of allowing heat flow across the pinch if the economic versus operating trade-offs suggest it, is that the optimal HEN structures that are obtained in Ciric and Floudas (1990) are simple and do not feature by-pass streams. As a result, these structures may be more interesting from the practical application point of view. 

The catalytic activation of aromatic C-H bonds leading to useful addition with new C-C bond formation is of considerable interest in organic synthesis and industrial processes, because it would provide simple and economical methods for producing aryl-substituted compounds directly from simple arenes, as shown in Scheme 1. 

Exposed multiple bonds of angular arenes are specifically prone to oxidation. The synthetic value of such double bonds arises from their high reactivity towards simple electrophiles, enophiles, and radicals. Heavy metal catalysis, periodate oxidation, and ozonolysis are the standard tools for oxidative bond cleavage in these substrates. For economic and ecological reasons, technically applicable alternatives are of great interest. Phenanthrene (29) represents a typical substrate... 

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