Thermoluminescence: Potential Applications in Forensic Science

In crime laboratories one of the most difficult operations is to determine unequivocally whether or not two samples of evidence of the same type were originally part of the same thing or were from the same source. It has been found that high temperature thermoluminescence (room temperature to 723 K) can be used for comparisons of this type, although work to date indicates that there is generally a finite probability for coincidental matching of glass or soil samples. Further work is required to determine and attempt to minimize these probabilities for different types of materials, and to define more clearly the scope of applicability of thermoluminescence to actual forensic situations

Prepolymer dianhydrides

A process for preparing dianhydrides that are miscible with hydroxyl prepolymers at moderate temperatures and can cure hydroxyl prepolymers to elastomers at moderate temperatures is disclosed. The dianhydrides are prepared by solution reaction of a prepolymer diol with excess hydride followed by removal of unreacted dianhydride. The prepolymer dianhydrides are miscible with hydroxyl substituted hydrocarbon prepolymers and cure the prepolymers to polyester-linked elastomers

New polymer systems: Chain extension by dianhydrides

Three anhydrides provide effective chain extension of hydroxy-terminated polyalkylene oxides and polybutadienes. Novel feature of these anhydride reactants is that they are difunctional as anhydrides, but they are tetrafunctional if conditions are selected that lead to total esterification or reaction of all carboxyl groups

Isostatic compression process converts polyaromatics into structural material

Isostatic compression process compacts certain powdered aromatic polymers into homogeneous materials that can be machined to form useful components, such as bearings. It provides for complete removal of air in the interstitial spaces surrounding the granules of the powdered polymer before the powder is subjected to isostatic compression

Method for estimating solubility parameter

Semiempirical correlations have been developed between solubility parameters and refractive indices for series of model hydrocarbon compounds and organic polymers. Measurement of intermolecular forces is useful for assessment of material compatibility, glass-transition temperature, and transport properties

Dual membrane hollow fiber fuel cell and method of operating same

A gaseous fuel cell is described which includes a pair of electrodes formed by open-ended, ion-exchange hollow fibers, each having a layer of metal catalyst deposited on the inner surface and large surface area current collectors such as braided metal mesh in contact with the metal catalyst layer. A fuel cell results when the electrodes are immersed in electrolytes and electrically connected. As hydrogen and oxygen flow through the bore of the fibers, oxidation and reduction reactions develop an electrical potential. Since the hollow fiber configuration provides large electrode area per unit volume and intimate contact between fuel and oxidizer at the interface, and due to the low internal resistance of the electrolyte, high power densities can be obtained

GABAergic inhibition controls neural gain in inferior colliculus neurons sensitive to interaural time differences

We investigated the role of GABAergic inhibition on the responses of inferior colliculus (IC) neurons sensitive to interaural time differences (ITDs) in anesthetized guinea pigs. Responses to static and dynamic ITDs were obtained before, during, and after recovery from ionotophoretic application of GABA, or antagonists to the GABA(A) receptor gabazine and bicuculline. For most neurons, a linear relationship was observed between discharge rates evoked by a particular ITD during drug application and control discharge rates. Blocking GABAergic inhibition, or adding exogenous GABA, scaled IC discharge rates in a multiplicative (divisive) and/or additive (subtractive) manner. When the influence of iontophoresed GABA antagonists or exogenous GABA on discharge rates was accounted for, GABAergic inhibition was found to have no effect on the ITD tuning properties of IC neurons. The tuning sharpness of ITD functions, the ITD that evoked 50% response magnitude, and the relative symmetry of ITD functions around their peak response were unaffected by blockade of inhibition or addition of tonic inhibition. However, the ability of neurons to discriminate between ITDs by virtue of differences in their discharge rate was altered by blocking or adding GABA. We propose that inhibition in the IC is involved in the control of the neural gain of the output of IC neurons rather than the regulation of ITD tuning. This gain control appears to arise from a combination of additive and multiplicative processes, and may involve mechanisms such as shunting inhibition or changes in the efficacy of inhibitory and excitatory inputs

Elastomer coated filler and composites thereof comprising at least 60% by weight of a hydrated filler and an elastomer containing an acid substituent

The impact resistance of flame retardant composites, especially thermoplastic molding: compounds containing over 60% hydrated mineral filler such as Al(OH)3 or Mg(OH)2 as improved by coating the filler with 1 to 20% of an elastomer. The composite will fail by crazing or shearing rather than by brittle fracture. A well bonded elastomeric interphase resulted by utilizing acidic substituted resins such as ethyl-hexyl acrylate-acrylic acid copolymers which bond to and are cross-linked by the basic filler particles. Further improvement in impact resistance was provided by incorporating 1 to 10% of a resin fiber reinforcement such as polyvinyl alcohol fibers that decompose to yield at least 30% water when heated to decomposition temperature

ECUT: Energy Conversion and utilization Technologies program biocatalysis research activity. Generation of chemical intermediates by catalytic oxidative decarboxylation of dilute organic acids

A rhodium-based catalyst was prepared and preliminary experiments were completed where the catalyst appeared to decarboxylate dilute acids at concentrations of 1 to 10 vol%. Electron spin resonance spectroscoy was used to characterize the catalyst as a first step leading toward modeling and optimization of rhodium catalysts. Also, a hybrid chemical/biological process for the production of hydrocarbons has been assessed. These types of catalysts could greatly increase energy efficiency of this process

Liquid ethylene-propylene copolymers

Oligomers are prepared by heating solid ethylene-propylene rubber in container that retains solid and permits liquid product to flow out as it is formed. Molecular weight and viscosity of liquids can be predetermined by process temperature. Copolymers have low viscosity for given molecular weight