Polarimetric calibration of large-aperture telescopes. I. Beam-expansion method

A concept is described for the high-accuracy absolute calibration of the instrumental polarization introduced by the primary mirror of a large-aperture telescope. This procedure requires a small aperture with polarization-calibration optics (e.g., mounted on the dome) followed by a lens that opens the beam to illuminate the entire surface of the mirror. The Jones matrix corresponding to this calibration setup (with a diverging incident beam) is related to that of the normal observing setup (with a collimated incident beam) by an approximate correction term. Numerical models of parabolic on-axis and off-axis mirrors with surface imperfections are used to explore the accuracy of the procedure.     

Helping counselor trainees learn to respond consistently to anger and depression.

50 graduate students were randomly divided into 5 groups that were exposed to different kinds of videotaped counselor training procedures. The group of main interest was exposed to a training procedure that enabled the Ss 1st to verbally practice responding to client negative affect and then to observe a model counselor's response. When these Ss counseled either angry or depressed role-playing clients, they responded more consistently to client feelings than did Ss exposed to other training procedures. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduction of low voltage power cables electromagnetic field emission in MV/LV substations

In this paper a solution to reduce magnetic field emission levels generated by MV/LV substation power cables is proposed. The reduction is obtained by the arrangement of the phases in a proper way and by shielding the cables with magnetic or conductive materials. The effects introduced by these two options have been analyzed by means of simulations, using finite elements method calculation software, and by experimental measurements. The introduced results allow selecting an optimal arrangement and the best screening material in order to reduce the magnetic fields in those directions required to protect.     

Concentrator multijunction solar cell characteristics under variable intensity and temperature

The performance of multijunction solar cells has been measured over a range of temperatures and illumination intensities. Temperature coefficients have been extracted for three‐junction cell designs that are in production and under development. A simple diode model is applied to the three‐junction performance as a means to predict performance under operating conditions outside the test range. These data may be useful in guiding the future optimization of concentrator solar cells and systems. Copyright © 2008 John Wiley & Sons, Ltd.     

Inductive modeling of lithium-ion cells

Sandia National Laboratories has conducted a sequence of studies on the performance of lithium ion and other types of electrochemical cells using inductive models. The objectives of some of these investigations are: (1) to develop procedures to rapidly determine performance degradation rates while these cells undergo life tests; (2) to model cell voltage and capacity in order to simulate cell output under variable load and temperature conditions; (3) to model rechargeable battery degradation under conditions of cyclic charge/discharge, and many others. Among the uses for the models are: (1) to enable efficient predictions of battery life; (2) to characterize system behavior.

Inductive models seek to characterize system behavior using experimentally or analytically obtained data in an efficient and robust framework that does not require phenomenological development. There are certain advantages to this. Among these advantages is the ability to avoid making measurements of hard to determine physical parameters or having to understand cell processes sufficiently to write mathematical functions describing their behavior. We have used artificial neural networks (ANNs) for inductive modeling, along with ancillary mathematical tools to improve their accuracy.

This paper summarizes efforts to use inductive tools for cell and battery modeling. Examples of numerical results are presented.     

A simple,rapid and novel method based on salting-out assisted liquid–liquid extraction for ochratoxin A determination in beer samples prior to ultra-high-performance liquid chromatography coupled to tandem mass spectrometry

A novel, simple, easy and cheap sample treatment strategy based on salting-out assisted liquid-liquid extraction for ochratoxin A (OTA) ultra-trace analysis in beer samples using ultra-high-performance liquid chromatography-tandem mass spectrometry determination was developed. The factors involved in the efficiency of pre-treatment were studied employing factorial design in the screening phase and the optimal conditions of the significant variables on the analytical response were evaluated using a central composite face-centred design. Consequently, the amount of salt ((NH₄)₂SO₄), together with the volumes of sample, hydrophilic (acetone) and nonpolar (toluene) solvents, and times of vortexing and centrifugation were optimised. Under optimised conditions, the limits of detection and quantification were 0.02 µg l^?1 and 0.08 µg l^?1 respectively. OTA extraction recovery by SALLE was approximately 90% (0.2 µg l^?1). Furthermore, the methodology was in agreement with EU Directive requirements and was successfully applied for analysis of beer samples.     

Metabolic profile biomarkers of metal contamination in a sentinel terrestrial species are applicable across multiple sites

In this study, we addressed the question of whether an omic approach could genuinely be useful for biomarker profile analysis across different field sites with different physicochemical characteristics. We collected earthworms (Lumbricus rubellus) from seven sites with very different levels of metal contamination and prevailing soil type and analyzed tissue extracts by 1H nuclear magnetic resonance spectroscopy. Pattern recognition analysis of the data showed that both site- and contaminant-specific effects on the metabolic profiles could be discerned. Zinc was identified as the probable major contaminant causing a metabolic change in the earthworms. Individual sites could be resolved on the basis of NMR spectral profiles by principal component analysis; these site differences may also have been caused by additional abiotic factors such as soil pH. Despite an inevitable degree of confounding between site and contaminant concentrations, it was possible to identify metabolites which were correlated with zinc across all different sites. This study therefore acts as a proof of principle for the use of NMR-based metabolic profiling as a diagnostic tool for ecotoxicological research in polluted field soils.