Experimental study of transient forced convection heat transfer from simulated electronic chips

Experiments are performed to study the single-phase transient forced convection heat transfer on an array of four in-line, flush-mounted simulated electronic chips in a vertical rectangular channel. Water is the coolant media and the flow covers the wide range of laminar flow regime with Reynolds number, based on heat source length, from 800 to 2,625. The heat flux ranges from 1 W/cm² to 7 W/cm². The heat transfer characteristics are studied and correlations are presented. The transient correlation for overall data recommended is Nu= 0.945(Pe ^1/3) Fo^–1/2.     

Some industrial developments and applications of multidimensional techniques

Industrial analytical chemistry includes the measurement of the elemental composition and structure of molecules; the measurement of the concentration of specific molecules, atoms, and ions in contact with other molecules, atoms, and ions, the measurement of the energy and speed with which these reactions occur; and the separation of molecules, atoms, and ions specifically from other molecules, atoms and ions. It is also the measurement of the physical (interaction) and chemical (reaction) behavior of collections of molecules and how this behavior is controlled by the presence of other molecules and ions. Many excellent devices for separation and measurement have been developed to accomplish these tasks. Each of these attains a level of sensitivity and selectivity beyond which further improvement would be difficult. However, by coupling these techniques in various configurations, improved data can be generated in a short time span. Such techniques are often referred to as hyphenated, tandem, combined, or coupled. A more inclusive term is multidimensional techniques. In this paper, we briefly describe some of the most significant developments our laboratory has made in these and related techniques.     

Thermal hazard evaluation of styrene polymerization by accelerating rate calorimetry

The thermal polymerization of inhibited styrene monomer is investigated by Accelerating Rate Calorimetry (ARC). The time-temperature-pressure data generated by this technique are utilized in evaluating the thermal hazards associated with the industrial processing of styrene monomer. Several examples are given on the interpretation and application of ARC data to environments ranging from lab to plant-scale conditions including discussions concerning the similarities and dissimilarities between the ARC and large-scale equipment. The polymerization of styrene monomer is also used to evaluate the performance of the ARC over a broad temperature range, 80–300°C. The data indicate that removal of the radiant heater assembly yields better agreement between the heat of polymerization of styrene as measured by the ARC and corresponding values from the literature. This effect is believed to be observable only under conditions of low reaction rates for long periods of time such as in the case of styrene monomer.     

Competitive and consecutive eliminations of N2 and CO (or C2H4) from some heterocyclies under electron impact

High resolution mass spectrometry was used to study two types of expected primary competing reactions triggered by two isobaric structural groups in some heterocyclic compounds, I-V, under 70 eV electron impact. The reactions are In both cases, it was found that the primary loss was exclusively a N₂ molecule which is then followed by the loss of CO or C₂ H₄.     

Mass spectrometric studies of phenoxarsine derivatives

Nine phenoxarsine derivatives with arsenic in the trivalent state and the pentavalent state are synthesized and studied by mass spectrometry. Their characteristic fragmentation modes and the fragment ions with common structures are discussed. Phenoxarsinic acids are found to be unstable in the gaseous phase at the temperatures studied and tend to form their corresponding anhydrides.     

Mass spectrometric study of 1-chloro-2-nitrosocycloalkanes,dimers in gaseous phase

The electron-impact mass spectra and the field ionization mass spectra of 1-chloro-2-nitrosocyclohexane and 1-chloro-2-nitrosocyclopetane are presented and discussed. The two compounds investigated exist in dimeric form in the gaseous phase.     

The homogeneization quenching of platinum

In this paper the defect structure of platinum during homogeneization quenching has been studied by transmission electron microscopy on electropolished foils. Several black dots about 100 Å in diameter have been observed on the foils, corresponding to a density of the order of 10¹⁴ ?3. The dots have been interpreted as clusters of vacancies retained in the presence of impurities. The analysis of the number of quenched-in vacancies leads to the conclusion that the clusters are spherical and about 110 Å in diameter. In contrast to copper no dislocation density growth with the number of quenchings could be observed as the dislocation density is less than 10⁸ cm^?2, which could not be detected exactly enough by the electron microscope method.     

Sb-NMR/NQR study of CeIrSb

We report Sb-NMR/NQR measurements on a valence fluctuating compound CeIrSb, which is isostructural to the Kondo semiconductors CeRhSb and CeNiSn. The nuclear spin-lattice relaxation rate divided by temperature, 1/T₁T has a maximum around 300 K and considerably decreases in proportion to T² when cooling down, followed by a 1/T₁T∼const. behavior below 20 K. These results indicate that CeIrSb has a V-shaped pseudogap with a residual density of states at the Fermi level. The size of pseudogap for CeIrSb is estimated to be about 350 K, which is one order of magnitude larger than the values of 28 K for CeRhSb and 14 K for CeNiSn. The larger size of energy gap in CeIrSb may be attributed to much stronger c-f hybridization than those for CeRhSb and CeNiSn.