Automated lifetime monitoring for factory process control

A methodology is described for using automated lifetime measurements as a diagnostic tool and process monitor in the fabrication of HgCdTe detectors. The influence of background flux on the accuracy of these measurements is quantified using a new high-level injection model. Automated lifetime testing, applied to a large set of anneal experiments, has identified a mid-gap recombination center that is repeatably generated by quenching after the stoichiometric anneal. Lifetime reduction associated with this center is found to correlate both with the degree of compensation and with the amount of indium dopant. Passivation with CdTe is found effective in mitigating the effect.     

Air-cleaning System Effectiveness for Control of Airborne Microbes in a Meat-processing Plant

ABSTRACT: :
The effectiveness of duct-mounted and console wall-mounted germicidal air cleaning units on the reduction of airborne microbes was determined. Preliminary air samples were collected and airborne bacteria and molds were monitored over time in the retail sales room, processing room, aging cooler and chill cooler of the Auburn Univ. Meat Laboratory. Log₁₀ cfu/m³ bacteria and molds were not reduced by filtration of fresh air in the air duct of the sales room(P > 0.05). After at least 18 h of filtration, 3 or 4 console filtration units operated simultaneously were effective (P ≤ 0.05) at reducing airborne bacteria and molds under controlled conditions in the processing room, aging cooler, and chill cooler. Three console filtration units reduced (P ≤ 0.05) airborne molds under production conditions in the processing room. These data suggest that an electrostatically polarized filter medium combined with scanning UV light is effective in reducing airborne microorganisms in a small processing plant.     

Magnetisme et conductivite des siliciures Y2Mn3Si5 et Lu2Mn3Si5

Y₂Mn₃Si₅ and Lu₂Mn₃Si₅ order ferrimagnetically at T_N = 96 and 56 K respectively; their resistivity strongly decreases at the transition from paramagnetic to ferrimagnetic phase. A model is proposed for the magnetic coupling.Two new silicides with the Sc₂Fe₃Si₅-type structure are characterized by X-ray powder diffraction : Gd₂Mn₃Si₅ and Yb₂Mn₃Si₅.     

Electrical Characteristics of Chronically Implanted Platinum-Irdium Electrodes

The electrical characteristics of platinum 30 percent-iridium microelectrodes implanted in the cruciate gyrus of cats were monitored during pulsing with charge-balanced, symmetric, cathodicfirst, controlled-current pulse pairs. The amplitude of the pulses spanned the range shown in other studies to be effective as neuronal stimuli, but not to induce histologic or physiologic damage in brain tissue adjacent to the microelectrode tips (10-80 ?, A). Two inflections on the cathodic and anodic charging transients induced by the controlled-current pulses were identified as being due to evolution of molecular hydrogen and the adsorption of oxygen, respectively. Despite the pH dependence of the equilibrium potential of these faradaic reactions, the electrode potentials at the inflections were shown to be independent of stimulus current over most of the useful range of stimulus intensities (20-80/?A, 200-800 ?IC/cm2, and 1-4 A/cm2). Hence, these inflections are valid markers of the true electrode potential, independent of accurate computation of access impedance or a stable reference electrode potential. The implications for monitoring the performance of chronically implanted microelectrodes and for the selection of stimulus parameters is discussed.     

Nd substitution in y/ba sites in melt processed YBa2Cu3O7− δ through Nd2O3 additions

YBa₂Cu₃O_{7− δ} (Y123) samples with excess Nd₂O₃ and Y₂O₃ additions in the same molar ratios were melt textured in air. In the Nd-doped samples, in addition to Y ion site substitution, partial substitution into the Ba²⁺ sites is anticipated because of the similar ionic sizes of Nd³⁺ and Ba²⁺. The microstructure, T_c, and magnetic properties of Nd-doped samples were analyzed and compared with undoped Y123 and samples with excess Y₂O₃. The Nd₂O₃ additions lead to significant magnetization improvements, likely due to both rare earth- and Ba-site substitution by the doped Nd³⁺ ions, and to increases in T_c. Y₂O₃ additions resulted in no marked property enhancement.     

Toxic Peptides in Populations of Two Pergid Sawflies,Potential Biocontrol Agents of Brazilian Peppertree

Determination of the safety of agents prior to release is one of the most important research goals in biological control. In addition to concerns for the safety of non-target plants, determination of the potential toxic properties of new agents needs to be assessed. Numerous phytophagous insects are defended by chemicals against the attack of natural enemies. Some of these defensive compounds could pose an environmental risk if an agent is released. Here, larval populations of two pergid sawflies, Heteroperreyia hubrichi and H. jorgenseni, were analyzed by LC-MS/MS to investigate whether they contain alleged toxic peptides. The first species is a potential candidate for biological control of the invasive weed Brazilian peppertree in Florida and Hawaii. The chemical analyses revealed the presence of the peptides pergidin (Perg), 4-valinepergidin (VPerg), dephosphorylated pergidin (dpPerg), lophyrotomin (LGln and LGlu). The effect of sawfly population for each species was significantly influencing peptide concentration. All peptides occurred at lower concentrations compared with purportedly toxic species of this sawfly family. However, the concentrations of the peptides are of concern for the welfare of wildlife and livestock that would be exposed to these species. These results demonstrate that release of this biological control agent in the invaded range may pose an environmental threat.     

Range measurements by a mobile robot using a navigation line

A continuous, straight-edged line is used for the visual navigation of an autonomous mobile robot in a factor environment. This line, which resides on the floor and contrasts with background, may also be used to determine range information. Two methods are developed for determining the range of an object in the sensor's field of view. The effects of various error conditions in the system geometry on each ranging method are determined. Equations are derived which yield the percent error in calculating ranges given estimates of these error conditions. Numerical examples using typical sensor parameters are given.     

Obtaining protein solvent accessible surface area when structural data is unavailable using osmotic pressure

Here, we provide an algorithm that predicts solvent accessible surface area (SASA) using concentrated solution osmotic pressure data. Sheep hemoglobin monomer and β‐lactoglobulin are used for verification. Additionally, SASA for structurally unknown calf lens α‐crystallin aggregate is predicted. Using osmotic pressure data, the predicted SASA value for sheep hemoglobin, 22,398 ± 1,244 Ų, was in excellent agreement with computational model predictions (24,304 Ų‐26,100 Ų). Similarly, predicted SASA values for bovine β‐lactoglobulin in pH solutions of pH 5.1, 6.0, and 8.0, were 5,765 ± 1,031 Ų, 6,656 ± 1,082 Ų, and 9,141 ± 1,060 Ų, respectively, were in good agreement with the computationally determined SASA value (7,500 Ų–8,628 Ų). Predicted SASA for the aggregate of calf lens α‐crystallin (800 kDa) was found to be 417,691 ± 16,790 Ų. These results illustrate that this novel method can provide an important experimental alternative in estimating SASA for proteins and, possibly, their complexes in solution. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

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