Computer program determines chemical equilibria in complex systems

Computer program numerically solves nonlinear algebraic equations for chemical equilibrium based on iteration equations independent of choice of components. This program calculates theoretical performance for frozen and equilibrium composition during expansion and Chapman-Jouguet flame properties, studies combustion, and designs hardware

Computer program for calculation of complex chemical equilibrium compositions

Computer program is described for numerical solution of chemical equilibria in complex systems by using nonlinear algebraic equations. Free-energy minimization technique is used

Computer program for calculation of ideal gas thermodynamic data

Computer program calculates ideal gas thermodynamic properties for any species for which molecular constant data is available. Partial functions and derivatives from formulas based on statistical mechanics are provided by the program which is written in FORTRAN 4 and MAP

Anytime Point-Based Approximations for Large POMDPs

The Partially Observable Markov Decision Process has long been recognized as a rich framework for real-world planning and control problems, especially in robotics. However exact solutions in this framework are typically computationally intractable for all but the smallest problems. A well-known technique for speeding up POMDP solving involves performing value backups at specific belief points, rather than over the entire belief simplex. The efficiency of this approach, however, depends greatly on the selection of points. This paper presents a set of novel techniques for selecting informative belief points which work well in practice. The point selection procedure is combined with point-based value backups to form an effective anytime POMDP algorithm called Point-Based Value Iteration (PBVI). The first aim of this paper is to introduce this algorithm and present a theoretical analysis justifying the choice of belief selection technique. The second aim of this paper is to provide a thorough empirical comparison between PBVI and other state-of-the-art POMDP methods, in particular the Perseus algorithm, in an effort to highlight their similarities and differences. Evaluation is performed using both standard POMDP domains and realistic robotic tasks

Computer Program for Calculation of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouguet Detonations. Interim Revision, March 1976

A detailed description of the equations and computer program for computations involving chemical equilibria in complex systems is given. A free-energy minimization technique is used. The program permits calculations such as (1) chemical equilibrium for assigned thermodynamic states (T,P), (H,P), (S,P), (T,V), (U,V), or (S,V), (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. The program considers condensed species as well as gaseous species

The Estimation of Prewar GNP: Methodology and New Evidence

The paper develops new methodology for the estimation of prewar GNP, taps previously unused data sources, and develops new estimates for the periods 1869-08 and 1869-28. Primary among the new data sources are direct measures of output in the transportation, communications, and construction sectors, and estimates of the consumer price index. New measures of real GNP, nominal GNP, and the GNP deflator are developed. The new estimates of real GNP are as volatile on average over the business cycle as the traditional Kuznets-Kendrick aeries but dampen the amplitude of some cycles while raising the amplitude of others. The new estimates of the GNP deflator are distinctly less volatile than the traditional series and in fact no more volatile than in the postwar period.

The Estimation of Prewar GNP Volatility, 1869-1938

New evidence is provided to assess the recent controversy regarding the volatility of real economic activity before 1929 relative to the period since World War II. Some recent work claims that the longstanding stylized fact of greater prewar volatility is "spurious". In contrast, this paper reconfirms the greater amplitude of business fluctuations prior to the Great Depression. The basic technique is the regression method, which estimates equations for real GNP during 1909-38, with one or more explanatory variables for components of GNP, and then uses the estimated coefficients to "backcast" real GNP or the period 1869-1908. The paper contains an extensive examination of the sensitivity of these regression indexes to alternative dependent variables, sample periods, detrending methods, and the inclusion of alternative explanatory variables. Particular attention is paid to the conflicting evidence regarding the amplitude of cycles in construction activity between 1870 and 1890. The resulting prewar/postwar volatility ratios, for 1869-1928 as compared to 1950-1980, range from 1.43 to 2.16. The paper concludes by suggesting that this range of volatility ratios is more likely to understate than overstate the prewar/postwar volatility ratio.

Spectral isolation of bi-invariant metrics on compact Lie groups

We show that a bi-invariant metric on a compact connected Lie group $G$ is spectrally isolated within the class of left-invariant metrics. In fact, we prove that given a bi-invariant metric $g_0$ on $G$ there is a positive integer $N$ such that, within a neighborhood of $g_0$ in the class of left-invariant metrics of at most the same volume, $g_0$ is uniquely determined by the first $N$ distinct non-zero eigenvalues of its Laplacian (ignoring multiplicities). In the case where $G$ is simple, $N$ can be chosen to be two.Comment: 10 pages, new title, revised abstract and introduction, minor typos corrected, to appear in Ann. Inst. Fourier (Grenoble

Surgical complications in human orthotopic liver transplantation.

Between March 1, 1980 and December 31, 1984, 393 orthotopic liver transplantations (OLT) were performed in 313 consecutive recipients. Technical complications were responsible for a substantial morbidity (41/393 allograft loss--10.4%) and mortality (26/313 patient loss--8.3%). Failure of the biliary tract reconstruction, mainly expressed as leakage and obstruction, is the most frequent complication of OLT (52/393 grafts--13.2%). Biliary tract complication (BTC) was directly responsible for 5 deaths (9.6%). Reliance upon standardized methods of direct duct-to duct repair with T-tube (CC-T) and Roux-Y choledocho-jejunostomy (RYCH-J), appropriate postoperative investigation and treatment will reduce morbidity and mortality of BTC. A complicated CC-T will be conversed to a RYCH-J; a complicated RYCH-J needs surgical correction. Hepatic artery thrombosis (HAT) has become the "Achilles heel" of OLT. HAT is expressed by three different patterns: fulminant hepatic necrosis, delayed bile leakage and relapsing bacteremia. Diagnosed in 27 grafts (6.8%), HAT was responsible for 16 deaths (16/25 pat: 64%). The only chance to rescue patients presenting HAT is an early diagnosis and prompt retransplantation before occurrence of septic complications. Aneurysm of the hepatic arterial supply (4/393 grafts--1%) also needs aggressive surgery because of the high rate of fatal rupture (3/4 pat--75%). The incidence of thrombosis of the reconstructed portal vein (PVT) was only 2.2% (7 pat.), three inferior vena caval thromboses (0.9%) (CVT) were diagnosed after OLT. Four of the 7 patients whose portal veins clotted are alive. Three have their original graft. One patient, presenting both PVT and CVT, was rescued by prompt retransplantation. PVT was responsible for 3 patient (3/7 pat--42.8%) and 4 graft losses (4/7 pat--57%). The rate of graft (3/3) and patient loss (2/3) was even higher after CVT

Quantum-mechanical communication theory

Optimum signal reception using quantum-mechanical communication theor