Review of Chemometrics Applied to Spectroscopy: 1985-95, Part 3 — Multi-way Analysis

INTRODUCTION

In this third part of a review on chemometrics in spectroscopy we will describe a recent methodology that has attracted increasing interest in spectroscopy. namely multi-way analysis. The application of multi-way analysis in spectroscopy is still relatively new. hence many methodological improvements are being investigated currently. Part of thls review will also be used to describe the algorithmic improvements gained the last decade.     

DIFFRACTION STUDIES OF SOME CONVENTIONAL AND NOVEL MICROPHONE BAFFLES

A directional microphone system for field recording of sounds in the air often involves a parabolic reflector to focus the sound waves on the microphone (transducer) element. Some deficiencies of such a system are noted with respect to reproduction of spectra. The reflector system, involving as it does a structure comparable to a wavelength in linear dimension, is not susceptible to traditional high- or low-frequency approximate methods of computation. Modern numerical techniques now permit precise calculation of the directional responses of small reflectors of various shapes. One result is a proposal for a very economical and effective system involving a plane reflector. Other baffle shapes are also investigated, which may be of interest in special applications.     

Oxidative ring opening of 3-hydroxyquinoline-2,4(1H,3H)-diones into N-(α-ketoacyl)anthranilic acids

N-(α-Ketoacyl)anthranilic acids were prepared by oxidative ring opening of 3-hydroxyquinoline-2,4(1H,3H)-diones by using paraperiodic acid (H₅IO₆) or sodium periodate (NaIO₄). The optimisation of the reaction conditions is described as well as the utilisation of N-(α-ketoacyl)anthranilic acids in the preparation of anthranilic acid hydrochlorides.     

A unique vibrational signature of rotated water monolayers on Pt(111): predicted and observed

Six H-bonds in the periodic di-interstitial structure that accounts for scanning tunneling microscope images of "√37" and "√39" wetting layers on Pt(111) are some 0.2 A? shorter than H-bonds are in ice Ih. According to a broadly obeyed correlation, this density functional theory result implies a stringent test of the di-interstitial motif, namely the presence of an OH-stretch band red-shifted from that of ice Ih by more than 1000 cm(-1). Infrared absorption spectra satisfy the test, in showing a feature centered at about 1965 cm(-1), which grows in as deposited water orders.     

The General Valence Force Field of Ethylene

During the course of studies of the vibrational spectra of type molecules, it was found that differences in the results of force constant calculations were obtained by various workers. This diversity in results can be attributed not only to differences in frequency assignments and in assumed force fields, but also in choice of coordinates. The present note deals with the two different sets of symmetry coordinates in common use by various authors for ethylene-type molecules.     

Hydrogen bonding, H-D exchange, and molecular mobility in thin water films on TiO2(110)

Hydrogen bonding, H-D exchange, and molecular mixing in water films on TiO2(110) have been studied using water electron-stimulated desorption. For T<70 K, films with different water isotopes adsorbed on the Ti4+ and bridging oxygen rows can be prepared. For T>70 K, H-D and molecular exchange between these "layers" occur with a distribution of activation energies and is surprisingly efficient. The results demonstrate that all the water molecules that are directly bound to TiO2(110) -- i.e., in the first and second monolayers -- are also hydrogen bonded to each other.     

Gas bubble pulsation in a semiconfined space subjected to ultrasound

In the case of ultrasound application in biological tissues, gas bubbles might form and collapse within cells, in the intercellular spaces and on tissue surfaces. In this work the effect of confined space on the behavior of the gas bubble in the presence of ultrasonic field is studied. A numerical model for bubble pulsation in a planar liquid layer, bounded by two rigid walls, is developed. Surface tension at the interface between the host liquid and the gas in the bubble is considered as well. A mathematical statement and solution technique based on the boundary integral method are presented. In some cases, the bubble divides into two symmetrical parts and high-velocity jets are generated, aimed at the walls. The final velocity of the jets strongly depends on the surface tension of the host liquid. Two new parameters that predict the occurrence of jet formation are developed.     

Sulfur gas tolerance and toxicity of co-utilizing and methanogenic bacteria

Anaerobic bacteria have been shown to be capable of converting CO, H₂, and CO₂ in synthesis gas to valuable products, such as acetate, methane, and ethanol. However, synthesis gas also contains small quantities of sulfur gases such as H₂S and COS, that may inhibit the performance of these organisms. This paper compares the performance of several CO-utilizing and methanogenic bacteria in converting CO, CO₂, and H₂ to products in the presence of various concentrations of H₂S and COS. The sulfur gas toxicity levels, growth, substrate uptake, and product formation for each organism are compared.     

Eigenvalues of the difference and product of projections

There is an isomorphism between the matrices over the Boolean algebra of subsets of a k-element set and the k-tuples of Boolean binary (i.e. zero-one) matrices. This isomorphism allows many problems concerning nonbinary Boolean matrices to the referred to the binary ease. However, there are some features of the general (i.e. nonbinary) case that have not been mentioned, although they differ somewhat from the binary case. We exhibit characterizations of the linear operators that preserve several invariants of matrices over finite Boolean algebras to illustrate the differences and similarities of the general vs. the binary cases. We employ a canonical form that is useful in applying the isomorphism.     

A hybrid OPCPA/Nd:phosphate glass multi-terawatt laser system for seeding of a petawatt laser

To enhance radiographic abilities on its Z-Accelerator, Sandia National Laboratories is incorporating a petawatt laser system into the existing Z-Backlighter laser facility. As part of this work, a short-pulse laser has been constructed to seed the larger Beamlet type Nd:phosphate glass slab amplifiers. This seed laser consists of an optical parametric chirped pulse amplification (OPCPA) system joined to a Nd:phosphate glass rod amplifier system in order to achieve multi-Joule sub-picosecond operation. The rod amplifier system has been modeled using the Miró code which shows good agreement with the experimental results. This system can achieve focal intensities up to 10¹⁸ W/cm² at a repetition rate of once every 20 min and has been applied to produce k-alpha X-rays in copper.