A new technique for precedence-ordering chemical process equation sets

An algorithm that combines structural equation analysis with algebraic rearrangement and substitution has been developed to precedence-order algebraic chemical process equations. The SWS (Structural Analysis with Substitutions) algorithm selects an output variable for each equation, rearranges the equation to solve for that variable, and reduces the number of equations by substitution. The algorithm has been used for computer generation of Fortran programs to perform meterial and energy balances in the design of chemical processes.     

Computation of forced convection in slow flow through ducts and packed beds—I extensions of the graetz problem

A computational study of forced convection processes in ducts and packed beds at low Reynolds numbers has been made. The results give a better understanding of these processes, especially for small Peclet numbers. It is demonstrated that two distinct forms of Nusselt numbers are relevant for low Peclet numbeRs. One, used mostly by theorists, is related to the local driving force; the other, used mostly by experimentalists, is related to easily measurable temperatures and concentrations. As an example the Graetz problem has been solved numerically over a wide range of Peclet numbers, and new asymptotes have been obtained for the region of small Peclet numbers.     

The nuclear export policy of the Reagan administration

The Reagan Administration maintains the Carter Administration's objective of non-proliferation of nuclear weapons as being fundamental to US nuclear export policy. However, it sees the USA as having another important role to play in influencing the use of nuclear power and the trading of related goods and technologies in other countries. While the Administration believes its policies will prove beneficial to the USA, there is concern that trade considerations are being given priority over preventing the proliferation of nuclear weapons.     

An improved numerical interconversion for creep compliance and relaxation modulus

An imporved method for the numerical evaluation of the convolution integral in the relationship between creep compliance and relaxation modulus is discussed. The better approximation is obtained by the assumption that both functions can be assumed to be linear within a series of increasing time intervals which do not change as the calculation progresses. The calculation is carried out on both hypothetical and real examples which substantiates its applicability and accuracy.     

Internal friction,acoustic emission and fatigue in metals for high amplitude ultrasonic frequencies

High amplitudes (strains up to 3 × 10^?3) have been used in studying internal friction, acoustic emission and fatigue in metals. The internal friction in the high amplitude range is due to breakaway of dislocations from pinning points and by the generation of Frank-Read loops which results in plastic strain. There are two plastic regions, one when the added loops are held up by the grain boundaries, and the second when the loops break through the grain boundaries. In the second region, slip bands are produced in the metal. As the amplitude increases slip bands can join up and fatigue in the metal occurs. Ultrasonic frequencies are useful for studying fatigue since a large number of cycles can occur in a reasonable time.Acoustic emission—that is, a noise in the sample associated with the dislocation motion—can be studied by putting transducers on the sample. It is shown that the emission is closely associated with the internal friction since it goes through two regions in the plastic range.     

Personality differences between fee-paying and non-fee paying patients seen for psychological testing.

Administered the MMPI to 17 21-62 yr old male patients who did not pay their clinic bills and 17 patients who did pay their bills. MMPI and clinical data suggest greater reality disturbance and distortion for the non-fee paying group than for the fee-paying group, and that fee-payment behavior is situationally determined and not a generalized characteristic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Data fitting with geometric-programming-compatible softmax functions

Motivated by practical applications in engineering, this article considers the problem of approximating a set of data with a function that is compatible with geometric programming (GP). Starting with well-established methods for fitting max-affine functions, it is shown that improved fits can be obtained using an extended function class based on the softmax of a set of affine functions. The softmax is generalized in two steps, with the most expressive function class using an implicit representation that allows fitting algorithms to locally tune softness. Each of the proposed function classes is directly compatible with the posynomial constraint forms in GP. Max-monomial fitting and posynomial fitting are shown to correspond to fitting special cases of the proposed implicit softmax function class. The fitting problem is formulated as a nonlinear least squares regression, solved locally using a Levenberg–Marquardt algorithm. Practical implementation considerations are discussed. The article concludes with numerical examples from aerospace engineering and electrical engineering.     

Volcanoes as a source of geothermal energy

The thermal energy available from high-temperature magma is calculated to be 8 × 10¹⁴ kcal/km³ and an upper bound for volcanic energy of 3 × 10¹⁸ kcal/volcano is determined. Approximately one-third of the energy may be obtained between about 750 and 1150 °C (i.e. above the solidification temperature of the magma), while the remaining two-thirds is available from magma in the solid state between ambient and around 750 °C. Gas dissolved in the magma possesses about 4% of the thermal energy and a large portion of that energy is potentially available as high-temperature steam. After removal of water, the gas remaining is a low-Btu gas with a heat of combustion of about 0.3 kcal/l. Utilization of both the thermal and combustion energy is the subject of current research projects.     

Economics of short-rotation intensive culture for the production of wood energy feedstocks

We review research and evaluate the economics of short-rotation intensive culture (SRIC) for the production of wood energy feedstocks in six regions of the U.S. The economics of SRIC are evaluated for present conditions under two sets of assumptions about anticipated advances in technology. The results show that delivered SRIC feedstock costs using available technology are likely to range between $3.00 and $4.10/GJ. Based on estimates of technological advances in tree breeding and selection, cultural management, and harvesting, delivered costs could be lowered to under $2.00/GJ. Advances in genetics, cultural management, and harvesting needed to reduce SRIC costs are technically attainable by the year 2000.