A High-Order Local Projection Stabilization Method for Natural Convection Problems

In this paper, we propose a local projection stabilization (LPS) finite element method applied to numerically solve natural convection problems. This method replaces the projection-stabilized structure of standard LPS methods by an interpolation-stabilized structure, which only acts on the high frequencies components of the flow. This approach gives rise to a method which may be cast in the variational multi-scale framework, and constitutes a low-cost, accurate solver (of optimal error order) for incompressible flows, despite being only weakly consistent. Numerical simulations and results for the buoyancy-driven airflow in a square cavity with differentially heated side walls at high Rayleigh numbers (up to \(Ra=10^7\)) are given and compared with benchmark solutions. Good accuracy is obtained with relatively coarse grids.     

Verified Code Generation for Embedded Systems

Digital signal processors provide specialized SIMD (single instruction multiple data) operations designed to dramatically increase performance in embedded systems. While these operations are simple to understand, their unusual functions and their parallelism make it difficult for automatic code generation algorithms to use them effectively. In this paper, we present a new optimizing code generation method that can deploy these operations successfully while also verifying that the generated code is a correct translation of the input program.     

Selective Laser Treatment on Cold-Sprayed Titanium Coatings: Numerical Modeling and Experimental Analysis

In this paper, a selective laser post-deposition on pure grade II titanium coatings, cold-sprayed on AA2024-T3 sheets, was experimentally and numerically investigated. Morphological features, microstructure, and chemical composition of the treated zone were assessed by means of optical microscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry. Microhardness measurements were also carried out to evaluate the mechanical properties of the coating. A numerical model of the laser treatment was implemented and solved to simulate the process and discuss the experimental outcomes. Obtained results highlighted the key role played by heat input and dimensional features on the effectiveness of the treatment.     

Wall effects for the pressure drop in fixed beds

A very simple model is presented for the effect of the container wall on the pressure drop in a fluid flowing through a bed of spheres. It is based on the application of the Ergun equation to the bulk region of the bed, unaffected by the wall. Pressure loss predictions are found to correspond well to the opposing trends reported in the literature for the viscous- and inertial-flow regimes.     

Migration of α-tocopherol and resveratrol from poly(L-lactic acid)/starch blends films into ethanol

Poly(L-lactic acid) (PLLA)/starch blends with various concentrations of two natural antioxidants, α-tocopherol (α-TOC) and resveratrol, were fabricated by a melt blending and compression molding processes. The effects of the two antioxidants on the optical (color), thermal and mechanical properties of PLLA/starch blends with antioxidants were assessed. PLLA/starch blend films with α-TOC and resveratrol showed a yellowish color influenced by the combined effect of white starch and the brown color of the antioxidants. The glass transition and melting temperatures were significantly reduced with the addition of antioxidants while enhanced thermal stability was observed, which could be a benefit and important for processing and production. The enhanced mechanical properties could be attributed to not only a compatibilization effect based on the chemical linkage between PLLA and starch chains, but also restriction of the chain mobility by antioxidants. The release of resveratrol from PLLA and PLLA/starch blend films into ethanol followed Fickian behavior. The D values of α-TOC were in the range of 0.47–3.95 × 10⁻¹¹ cm² s⁻¹ for PLLA films and 0.70–6.83 × 10⁻¹¹ cm² s⁻¹ for PLLA/starch blend films at 13 °C, 5.67–13.0 × 10⁻¹¹ cm² s⁻¹ for PLLA films and 4.10–24.2 × 10⁻¹¹ cm² s⁻¹ for PLLA/starch blend films at 23 °C, and 89.0–118.0 × 10⁻¹¹ cm² s⁻¹ for PLLA films and 123–282 × 10⁻¹¹ cm² s⁻¹ for PLLA/starch blend films at 43 °C. The D values of resveratrol were in the range of 0.073–0.54 × 10⁻¹⁰ cm² s⁻¹ for PLLA films and 1.42–6.93 × 10⁻¹⁰ cm² s⁻¹ for PLLA/starch blend films at 13 °C, 0.90–3.44 × 10⁻¹⁰ cm² s⁻¹ for PLLA films and 4.16–22.3 × 10⁻¹⁰ cm² s⁻¹ for PLLA/starch blend films at 23 °C, and 24.8–74.1 × 10⁻¹⁰ cm² s⁻¹ for PLLA films and 40.1–309 × 10⁻¹⁰ cm² s⁻¹ for PLLA/starch blend films at 43 °C.     

Identification of genes regulated by interleukin-1beta in human endometrial stromal cells

Interleukin-1beta (IL-1b) is an important immune regulatory factor that in human endometrium plays a role in both menstruation and implantation in the event of pregnancy. It promotes inflammatory-like processes and also stimulates tissue remodelling. We present a cDNA microarray study documenting the major effects of IL-1beta on gene expression in stromal cells from human endometrium. Endometrial stromal cells from five normal healthy women at the mid secretory phase were cultured with or without IL-1beta at 50 and 500 pg/ml for 48 h. cDNA microarrays were used to compare the levels of gene expression in total RNA isolated from cells stimulated with IL-1beta. These cDNA arrays were produced containing 15 164 sequence-verified clones, which included genes known to be important in angiogenesis, immune modulators, apoptosis, cell signalling, extra-cellular matrix (ECM) remodelling and cell cycle regulation. Genes which were regulated by IL-1beta were identified by analysis of the microarray data using the Significance Analysis of Microarrays software package. Upregulated (n = 23) and downregulated (n = 6) different genes were observed, which changed at least 3-fold, at a false discovery rate of less than 2% (P < 0.02). Our results have identified genes regulated by IL-1beta, which are involved in leukocyte recruitment, ECM remodelling and other cellular functions. Changes in three genes, IL-8, colony-stimulating factor 2 and aldoketo reductase family 1 member 1, which were upregulated by IL-1beta, were verified using real-time PCR. Novel functions regulated by IL-1beta in endometrium, including genes involved in free radical protection, and fatty acid metabolism were also identified. These results also provide new insights into the role of IL-1beta in disorders of the endometrium, especially in implantation-related infertility and endometriosis, in which this cytokine plays a major role.     

Environmental factors affect the activity of biocontrol agents against ochratoxigenic Aspergillus carbonarius on wine grape

The influence of temperature and relative humidity (RH) on the activity of three biocontrol agents-the yeast Metschnikowia pulcherrima LS16 and two strains of the yeast-like fungus Aureobasidium pullulans LS30 and AU34-2-against infection by A. carbonarius and ochratoxin A (OTA) accumulation in wine grape berries was investigated in lab-scale experiments. The presence of wounds on grape skin dramatically favored infection of berries by A. carbonarius strain A1102, since unwounded berries showed very low levels of infection at all conditions of RH and temperature tested. Artificially wounded berries pre-treated with the biocontrol agents were inoculated with the ochratoxigenic A. carbonarius strain A1102 and were incubated for 5days at two levels of RH (60% and 100%) and three different temperatures (20, 25 and 30°C). The three biocontrol agents were able to prevent infections at 60% RH and 20°C. At 60% RH and 25°C only strain AU34-2 achieved some protection on day 5, whereas at 30°C a limited biocontrol efficacy was evident only up to day 2. At 100% RH, LS16, LS30 and AU34-2 showed effective protection of grape berries at 20°C until the 5th day of incubation. The three biocontrol agents achieved significant protection at higher temperatures only until the 2nd day after the beginning of the experiment: all three strains at 25°C, and only strain LS16 at 30°C. After 5days, the three biocontrol agents were able to significantly reduce the level of OTA in berries at all the conditions tested. This occurred even when protection from infection was not significant, except at 30°C and 100% of RH for all the three strains, and at 25°C and 100% of RH for strain LS16. The biocontrol agents displayed a higher rate of colonization on grape berries at 20 and 25°C than at 30°C. The higher value of RH (100%) appeared to increase the rate of colonization, in particular at 20 and 25°C. Taken together, our results emphasize the significant influence of environmental factors on the effectiveness of biocontrol against A. carbonarius as well as on OTA contamination in wine grape berries, and the need for biocontrol agents that can cope with the environmental conditions that are conducive to attack by A. carbonarius.     

How do stressors lead to burnout? The mediating role of motivation.

We extend existing stressor-strain theoretical models by including intrinsic motivation as a mediator between well-established job stressors and burnout. Though the link between situational stressors and burnout is well established, little is known about mechanisms behind this relationship. With a sample of 284 self-employed individuals, we examined motivation as a mediator to explain why situational factors impact 3 dimensions of burnout: emotional exhaustion, cynicism, and inefficacy. Motivation is an explanatory mechanism that drives human behavior and thought, and thus may have an impact on important well-being outcomes. As expected, intrinsic motivation was a full mediator for the effect of perceived fit on the inefficacy dimension of burnout. Unexpectedly, neither perceived fit nor motivation was related to the other 2 dimensions of burnout, and role ambiguity had only a direct effect on the inefficacy dimension; it was also unrelated to exhaustion and cynicism. We discuss implications of these findings for researchers as well as for practitioners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The view from abroad on a parade of choices: Alternative processes to the ‘traditional’ alternative,arbitration

Mauro Rubino‐Sammartano , of Milan, Italy, discusses European alternatives to arbitration that have proven effective in resolving commercial disputes in a variety of forums.     

Harmonics and transient overvoltages due to capacitor switching

This work presents a study of the steady-state and transient effects of power factor correction capacitors on the utility and on the customer. In the presence of harmonic-producing loads, capacitors used for power factor correction can cause parallel or series resonance problems which tend to increase the total harmonic distortion (THD) of the voltage and current waveforms. The cases studied in this work considers the addition of a power factor correction capacitor, in the presence of downstream harmonic loads and at the harmonic load site. In both cases the resonance created by the addition of the capacitor caused the harmonic distortion of the voltage and current waveforms to increase. Another problem is transient overvoltages created by switching the capacitor. A case study is reported where the operation of a semiconductor controlled motor drive is effected by transient overvoltages