Physical Sciences and Mathematics Commons^™

Slip Length In A Dilute Gas, Alejandro Garcia, D. Morris, L. Hannon

Alejandro Garcia

We study the phenomenon of slip length using molecular dynamics and direct simulation Monte Carlo simulations of a dilute gas. Our work extends the range of Knudsen numbers that have been previously studied. In a recent paper, Bhattacharya and Lie [Phys. Rev. 43, 761 (1991)] suggest a logarithmic dependence of slip length on Knudsen number. By a simple redefinition of the mean free path, we obtain good agreement between simulation results and Maxwell theory for slip length. The anomalies seen by Bhattacharya and Lie appear to be due to their definition of the mean free path.

Proton–Donor Properties Of Water And Ammonia In Van Der Waals Complexes With Rare‐Gas Atoms. Kr–H2o And Kr–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Steve Scheiner

The perturbation theory of intermolecular forces in conjunction with the supermolecular Møller–Plesset perturbation theory is applied to the analysis of the potential‐energy surfaces of Kr–H₂O and Kr–NH₃ complexes. The valleylike minimum region on the potential‐energy surface of Kr–H₂O ranges from the coplanar geometry with the C₂ axis of H₂O nearly perpendicular to the O–Kr axis (T structure) to the H‐bond structure in which Kr faces the H atom of H₂O. Compared to the previously studied Ar–H₂O [J. Chem. Phys. 94, 2807 (1991)] the minimum has more …

Calculation Of Barriers To Proton Transfer Using Variations Of Multi-Configuration Self‐Consistent Field Methods. I. Combinations Of Orbitals, K. Luth, Steve Scheiner

Steve Scheiner

The usefulness of multiconfiguration self‐consistent‐field (MCSCF) calculations in computing correlated proton transfer potentials is investigated for the systems HF₂⁻, H₇N₂⁺, H₃O₂⁻, and H₅O₂⁺. In deciding whether to include particular molecular orbitals, it is important to consider the balance of electron density between the donor and acceptor groups and the interactions that are incorporated in the orbitals. Only orbitals which have the proper symmetry to interact with the transferring hydrogen need be included in the MCSCF active space. Reasonable transfer barriers are obtained …

Pulsed‐Laser Excited Differential Photothermal Deflection Spectrometry, Stephen E. Bialkowski, Xu Gu, Pete E. Poston, Linda S. Powers

Stephen E. Bialkowski

This paper describes a differential photothermal optical absorbance apparatus that uses two excitation beams at different wave-lengths. A single probe beam monitors the difference in heats generated by the two wavelengths. The theory is developed for the operational principles of the apparatus, and theoretical signals are compared with those obtained with a conventional absorption spectrophotometer. The differential photothermal apparatus has a theoretical advantage over conventional spectrophotometry for samples with less than unit absorbance. Experiments are described which verify the operating principles and demonstrate the flexibility of the apparatus.

Residual Waste Management: A Quick Guide To Decision-Making, John Dernbach

John C. Dernbach

No abstract provided.

High Performance Memory System Pct:Ep0199134, Robert Iannucci

Robert A Iannucci

No abstract provided.

On The Dirichlet Problem For The Degenerate Real Monge Ampère Equation, Bert Wachsmuth

Bert Wachsmuth

No abstract provided.

A Capacity Theory Of Comprehension: Individual Differences In Working Memory, Marcel Just, Patricia Carpenter

Marcel Adam Just

No abstract provided.

Adaptive Estimation In Timeseries Regression Models, Douglas Steigerwald

Douglas G. Steigerwald

I develop adaptive estimators for linear regression with serially correlated errors. The efficiency results hold even when the serial correlation structure is unknown. Simulations indicate that efficiency gains can be substantial with samples of only 50 observations. We apply the method to a study of forward exchange rates.

Industrial Waste Management, John Dernbach

John C. Dernbach

No abstract provided.

Chiral Invariance And Electroweak Interactions Of Pions And Kaons, Br Holstein

Barry R Holstein

Electroweak interactions of pions and kaons are studied in the context of chiral perturbation theory. We demonstrate that the effective Lagrangian framework allows a consistent and predictive picture of such processes as well as a succinct way in which to represent the many previous studies of these reactions which have been performed using chiral models.

Displacement, Velocity, And Frames Of Reference: Phenomenographic Studies Of Students’ Understanding And Some Implications For Teaching And Assessment, John Bowden, Gloria Dall'alba, Elaine Martin, D Laurillard, Ference Marton, Geoff Masters, Paul Ramsden, Andrew Stephanou, E Walsh

Prof Geoff Masters AO

Student understanding of fundamental concepts in kinematics has been explored using the phenomenographic research method. University and high schoolphysics students were interviewed and their understandings of displacement, velocity, and frames of reference have been analyzed in particular problem contexts. Descriptions of the different ways students understand the concepts have been developed and relations between the different levels of understanding have been identified. The data highlight the contextual nature of learning and the need for teachers to focus on the nature of student understanding in specific contexts using questions that require qualitative explanation by students. In particular, it is demonstrated that …

A High Yield Microscale Enzymatic Synthesis And Purification Of 14c‐Labeled Nicotinamide Adenine Dinucleotide Phosphate (Nadp+), Andre Ronneberg, Gordon Metz, Richard Weld, Peter Roffey, Chris Craney

Chris L. Craney

Uniformly labeled (U) 14C nicotinamide adenine dinucleotide phosphate (NADP+) was synthesized by phosphorylating [U-14C]nicotinamide adenine dinucleotide (NAD+) in the presence of immobilized NAD+ kinase. The 15 μCi (600 μL) synthesis consistently achieved yields between 80% and radiochemical purities greater than 95%. The [U-14C]NADP+ was purified by high performance anion-exchange chromatography using a gradient elution of ammonium bicarbonate. This procedure may be applicable to the synthesis of other charged, UV-absorbing products of enzyme-catalyzed reactions.

The Logic Of Unbalanced Subobjects In A Category With Two Closed Structures, Lawrence Stout

Lawrence N. Stout

No abstract provided.

On The Finite Sample Behavior Of Adaptive Estimators, Douglas Steigerwald

Douglas G. Steigerwald

With only 50 observations, the adaptive estimator produces confidence intervals that are 20 to 50 percent shorter than those produced by GLS procedures. The key feature is that the underlying error density is symmetric. Under asymmetry the interval length is shortened by a smaller amount.

Asymptotic Behavior Of Solutions Of A Linear Second Order Difference Equation, William F. Trench

William F. Trench

No abstract provided.

Mild Integrability Conditions For Global Solutions Of An Elliptic Equation, William F. Trench

William F. Trench

No abstract provided.

Global Solutions Of Nonlinear Differential Equations, William F. Trench

William F. Trench

No abstract provided.

A Course In Econometrics: A Review, Douglas G. Steigerwald

Douglas G. Steigerwald

No abstract provided.

A Class Of Direct Search Methods For Nonlinear Integer Programming, Stephen J. Sugden

Stephen Sugden

This work extends recent research in the development of a number of direct search methods in nonlinear integer programming. The various algorithms use an extension of the well-known FORTRAN MINOS code of Murtagh and Saunders as a starting point. MINOS is capable of solving quite large problems in which the objective function is nonlinear and the constraints linear. The original MINOS code has been extended in various ways by Murtagh, Saunders and co-workers since the original 1978 landmark paper. Extensions have dealt with methods to handle both nonlinear constraints, most notably MINOS/AUGMENTED and integer requirements on a subset of the …

Optical Transformations In Three-Space: Simulations With A Pc, Raymond G. Wilson, Sean M. Mccreary, Jeffrey L. Thompson

Raymond Wilson

Nuclear Emp Hardening Approach As The Basis For Unified Electromagnetic Environmental Effects Protection, George H. Baker Iii

George H Baker

Operation DESERT STORM demonstrated the clear military advantage that was provided by our sophisticated electronic C4I and weapons systems. High tech means so dominate the battlefield that the outcome of future conflicts could be decided by electronics attrition rather than human casualties. However, the electromagnetic threat landscape is highly complex. The already formidable list of environments (EMI, lighting, ESD, EMP, HERO, TEMPEST, EW, etc.) is lengthened by emerging threats from high power microwave (HPM) and ultra-wide band (UWB) electromagnetic weapons. Many of these environments overlap in the frequency and amplitude of the electrical stresses they create.

The large number of …

Sliding-Mode Observers Based On Equivalent Control Method, Sergey V. Drakunov

Sergey V. Drakunov

No abstract provided.

Structural Characterization Of Mixed Alkali Metal Bis(Trimethylsilyl)Amide Bases., Paul Williard, Michael Nichols

Michael A Nichols

No abstract provided.

Hepatic Microsomal N-Hydroxylation Of Aniline And 4-Chloroaniline By Rainbow Trout (Onchorhyncus Mykiss), Steven P. Bradbury, J. M. Dady, A. D. Hoffman, M. M. Voit, D. L. Olson

Steven P. Bradbury

N-Hydroxylation of aniline and 4-chloroaniline was quantified in rainbow trout microsomal preparations using h.p.l.c.-liquid scintillation methods. Radioactive phenylhydroxylamine and 4-chlorophenylhydroxylamine metabolites were identified by co-elution with non-labelled standards. The method provided resolution of metabolite standards, and quantification of both N-hydroxylated metabolites was achieved without derivatization. The maximum velocities at 25 degrees C were 33.8 +/- 1.40 and 22.0 +/- 0.98 pmol/min per mg for aniline and 4-chloroaniline N-hydroxylation, respectively. The Km values were 1.0 +/- 0.11 and 0.8 +/- 0.11 mM for aniline and 4-chloroaniline N-hydroxylation, respectively. These activities were not induced by treatment of the trout with Aroclor 1254 …

Polymer Research In Austria. I: Introduction And The Facilities, Otto Vogl, Josef Schurz, Bernd Thrattnigg, Klaus Hummel, Wolfgang Daimler, Klaus Lederer

Otto Vogl

No abstract provided.

Japan-U.S. Seminar On Polymer Synthesis, Otto Vogl, Hiroyuki Nishide

Otto Vogl

No abstract provided.

Reconstruction And Future Trends Of The Aids Epidemic In The United States, Ron Brookmeyer

Ron Brookmeyer

There has been considerable uncertainty in estimates of past and current human immunodeficiency virus (HIV) infection rates in the United States. Statistical estimates of historical infection rates can be obtained from acquired immunodeficiency syndrome (AIDS) incidence data and the incubation period. However, this approach is subject to a number of sources of uncertainty and two other approaches, epidemic models of HIV transmission and surveys of HIV prevalence, are used to corroborate and refine the statistical estimates. Analyses suggest the HIV infection rate in the United States grew rapidly in the early 1980s, peaked in the mid-1980s, and subsequently declined markedly. …

Linear Algebra By Analogy, Scott H. Hochwald

Scott H. Hochwald

No abstract provided.

Electrochemical And Spectroscopic Investigations Of The Properties Of Electrified Interfaces, Mark Anderson

Mark R. Anderson

No abstract is available at this time.