Series Prediction based on Algebraic Approximants

It is described how the Hermite-Pad\'e polynomials corresponding to an algebraic approximant for a power series may be used to predict coefficients of the power series that have not been used to compute the Hermite-Pad\'e polynomials. A recursive algorithm is derived and some numerical examples are given.Comment: 9 pages, ISRN Applied Mathematics, in pres

Correlation Energy Estimators based on M{\o}ller-Plesset Perturbation Theory

Some methods for the convergence acceleration of the M{\o}ller-Plesset perturbation series for the correlation energy are discussed. The order-by-order summation is less effective than the Feenberg series. The latter is obtained by renormalizing the unperturbed Hamilton operator by a constant factor that is optimized for the third order energy. In the fifth order case, the Feenberg series can be improved by order-dependent optimization of the parameter. Alternatively, one may use Pad{\'e} approximants or a further method based on effective characteristic polynomials to accelerate the convergence of the perturbation series. Numerical evidence is presented that, besides the Feenberg-type approaches, suitable Pad{\'e} approximants, and also the effective second order characteristic polynomial, are excellent tools for correlation energy estimation.Comment: 21 pages, 87 references, LaTeX2e, elsart.cls, uuencoded compressed tar file created by csh script uufiles. J. Mol. Struct. (THEOCHEM), in press. Postscript and dvi also available via http://www.chemie.uni-regensburg.de/preprint.html and ftp://rchs1.uni-regensburg.de/pub/preprint/TC-QM-96-

Design of a high-speed valve

A high‐speed valve has been designed for opening a deLaval nozzle in times less than 10^(−3) sec

A computer program for the generation of logic networks from task chart data

The Network Generation Program (NETGEN), which creates logic networks from task chart data is presented. NETGEN is written in CDC FORTRAN IV (Extended) and runs in a batch mode on the CDC 6000 and CYBER 170 series computers. Data is input via a two-card format and contains information regarding the specific tasks in a project. From this data, NETGEN constructs a logic network of related activities with each activity having unique predecessor and successor nodes, activity duration, descriptions, etc. NETGEN then prepares this data on two files that can be used in the Project Planning Analysis and Reporting System Batch Network Scheduling program and the EZPERT graphics program

DISCUSSION: FINANCING AGRICULTURAL RESEARCH AND EDUCATION IN A PERIOD OF TIGHT BUDGETS

Public Economics,

A multigrid continuation method for elliptic problems with folds

We introduce a new multigrid continuation method for computing solutions of nonlinear elliptic eigenvalue problems which contain limit points (also called turning points or folds). Our method combines the frozen tau technique of Brandt with pseudo-arc length continuation and correction of the parameter on the coarsest grid. This produces considerable storage savings over direct continuation methods,as well as better initial coarse grid approximations, and avoids complicated algorithms for determining the parameter on finer grids. We provide numerical results for second, fourth and sixth order approximations to the two-parameter, two-dimensional stationary reaction-diffusion problem: Δu+λ exp(u/(1+au)) = 0. For the higher order interpolations we use bicubic and biquintic splines. The convergence rate is observed to be independent of the occurrence of limit points

Spin-Lattice Relaxation in Metal-Organic Platinum(II) Complexes

The dynamics of spin-lattice relaxation (slr) of metal-organic Pt(II) compounds is studied. Often, such systems are characterized by pronounced zero-field splittings (zfs) of the lowest-lying triplets. Previous expressions for the Orbach slr process do not allow to treat such splitting patterns properly. We discuss the behavior of a modified Orbach expression for a model system and present results of a fit of the temperature dependence of the spin-lattice relaxation rate of Pt(2-thpy)$_2$ based on the modified expression.Comment: 9 pages, 3 figures (made from 4 .eps files), elsart.cls. Using dvips (dvipsk 5.58f), it may be necessary to manually edit the generated file letter.ps to change in the first line from PS-Adobe-2.0 to PS-Adobe-3.0. Chemical Physics Letters, in pres

Status of Pacific Mackerel spawning population, 1973

This is the first annual report of the status of the spawning population of the Pacific mackerel as required by Section 8388.3 of the Fish and Game Code. During 1972 and early 1973, several methods of determining population size were investigated as mechanisms for estimating the spawning population size of Pacific mackerel stocks north of Punta Eugenia, Baja California, and a method using tagging procedures proved to be the most acceptable. The estimate of the Pacific mackerel spawning population obtained by tagging procedures was 5,480 tons. This estimate agrees generally with those obtained from alternate methods in which previously computed spawning biomass estimates were correlated with partyboat catches in three different areas and the 1973 spawning biomass estimated from the resulting regression line. The estimates derived by these alternate methods are 6,970 tons, 4,730 tons, and 6,210 tons. All estimates are below the 10,000 ton spawning population minimum and thus there is no excess by which a harvest under Section 8388.5 of the Fish and Game Code could be allowed. (17pp.