A modeling approach to the evaluation of internal sorting methods

The purpose of this paper is to report a modeling approach to the evaluation of internal sorting methods. The technique used is a regression modeling technique and has been found to be a very fast statistical method for evaluation which relies on the performance of data collection from the system being evaluated. The parameters considered for evaluation are: (1) number of stages, (2) number of transfers, (3) number of records, (4) sort time, (5) number of comparisons. The empirical model has been developed for sorting time as a function of the number of stages, number of records, number of comparisons, and number of transfers. The correlation coefficient obtained during the process of modeling was an average of 0.96 and has been found statistically significant.     

Inhibition of enzymatic browning in foods and beverages.

Enzymatic browning is a major factor contributing to quality loss in foods and beverages. Sulfiting agents are used commonly to control browning; however, several negative attributes associated with sulfites have created the need for functional alternatives. Recent advances in the development of nonsulfite inhibitors of enzymatic browning are reviewed. The review focuses on compositions that are of practical relevance to food use.     

Sliding Wear of Al2O3–SiC–(Al,Si) Composites against a Steel Counterface

The sliding-wear behavior of Al₂O₃–SiC–Al composites prepared by melt oxidation against a steel counterface has been recorded in a pin-on-disk machine. At high speeds and pressures (10 m/s, 20 MPa), friction and wear appear to be principally controlled by the in-situ formation of an interfacial film that consists of a layer of Fe₃O₄. The formation of this film is examined as a function of sliding speed, lubrication, and composite microstructure. A model is proposed in which high surface temperatures cause the preferential extrusion of aluminum from the composite onto the pin/disk interface. This promotes the adhesive pickup of iron and its oxidation to form a stable tribologically beneficial layer of Fe₃O₄.     

Adenylyl cyclase 6 is selectively regulated by protein kinase A phosphorylation in a region involved in Galphas stimulation

Receptors activate adenylyl cyclases through the Galphas subunit. Previous studies from our laboratory have shown in certain cell types that express adenylyl cyclase 6 (AC6), heterologous desensitization included reduction of the capability of adenylyl cyclases to be stimulated by Galphas. Here we further analyze protein kinase A (PKA) effects on adenylyl cyclases. PKA treatment of recombinant AC6 in insect cell membranes results in a selective loss of stimulation by high (>10 nM) concentrations of Galphas. Similar treatment of AC1 or AC2 did not affect Galphas stimulation. Conversion of Ser-674 in AC6 to an Ala blocks PKA phosphorylation and PKA-mediated loss of Galphas stimulation. A peptide encoding the region 660-682 of AC6 blocks stimulation of AC6 and AC2 by high concentrations of Galphas. Substitution of Ser-674 to Asp in the peptide renders the peptide ineffective, indicating that the region 660-682 of AC6 is involved in regulation of signal transfer from Galphas. This region contains a conserved motif present in most adenylyl cyclases; however, the PKA phosphorylation site is unique to members of the AC6 family. These observations suggest a mechanism of how isoform selective regulatory diversity can be obtained within conserved regions involved in signal communication.     

Influence of deviation from stoichiometry on the photoluminescence in CdTe doped with indium

Low temperature photoluminescence of vacuum and cadmium annealed CdTe:In is reported here. A new peak at ∼ 1·14 eV related to transitions from the conduction band to an acceptor involving a tellurium vacancy has been observed.     

Numerical solution of a fourth-order ordinary differential equation

Summary In this paper we have derived numerical methods of orderO(h ⁴) andO(h ⁶) for the solution of a fourth-order ordinary differential equation by finite differences. A method ofO(h ²) was earlier discussed by Usmani and Marsden [6]. Convergence of the fourth-order method is shown. Two examples are computed to show the superiority of our methods.     

Analysis of elastothermodynamic damping in particle-reinforced metal-matrix composites

When a composite material is subjected to a homogeneous or inhomogeneous stress field, different phases undergo different temperature fluctuations due to the well-known thermoelastic effect. As a result, irreversible heat conduction occurs and entropy is produced. This entropy production is the genesis of elastothermodynamic damping. Recently, taking the second law of thermodynamics as a starting point, a general methodology for calculating the elasto-thermodynamic damping was presented by Kinra and Milligan. Using this method, we calculate the elastothermodynamic damping for two canonical problems concerning particle-reinforced metal-matrix composites: (1) a single spherical inclusion in an unbounded matrix and (2) anN layer finite concentric composite sphere. In both cases, a uniform radial time-harmonic loading is considered. This article is based on a presentation given in the Mechanics and Mechanisms of Material Damping Symposium, October 1993, in Pittsburgh, Pennsylvania, under the auspices of the SMD Physical Metallurgy Committee.     

A heuristic algorithm for optimal placement of rectangular objects

The problem of partitioning a two-dimensional area into pieces having certain sizes with a minimum of wasted space is very important, especially in packing components tightly in the manufacture of very large-scale integrated circuits. The purpose of this paper is to examine the problem of placing rectangular objects in a rectangular area so as to minimize the wasted space, from the viewpoint of establishing maximum empty rectangles rather than the standard linear-programming approach. A comparison of our results with those of the Steudel [5] is reported. Empirical comparisons of our results indicate that our algorithm is very simple and efficient.