Promising Features (promising + feature)

Distribution by Scientific Domains

Selected Abstracts

Evaluation of applied cathode potential to enhance biocathode in microbial fuel cells

Peng Liang
Abstract BACKGROUND: The biocathode is proving to be a promising feature for development of the microbial fuel cell (MFC), although much work remains to be done to increase its power generation. This study aimed to enhance the performance of a biocathode by applying selected cathode potential. RESULTS: When five two-chambered MFCs were operated at selected cathode potentials of 142, 242, 342, 442, or 542 mV (vs standard hydrogen electrode), those MFCs with selected potentials lower than 342 mV could start up, and the highest power density of 0.11 W m,3 was obtained at a selected potential of 242 mV. An inner-biocathode MFC was then constructed and operated at a start-up cathode potential of 242 mV for 30 days. The open circuit cathode potential increased from 477 ± 9 mV to 572 ± 8 mV compared with the potential of the initially abiotic cathode, resulting in an increase in the maximum power density (4.25 ± 0.16 W m,3) of 106%. In addition, tests of continuous operation showed that a loading rate of 135 mg COD L,1 d,1 was optimal for obtaining maximum power generation in the system developed for this study. CONCLUSION: The results indicated that an optimal cathode potential of 242 mV enhanced the performance of a biocathode using oxygen as the electron acceptor. Copyright © 2009 Society of Chemical Industry [source]

Characteristics of Immobilized Lipase on Hydrophobic Superparamagnetic Microspheres To Catalyze Esterification

Zheng Guo
A novel immobilized lipase (from Candida rugosa) on hydrophobic and superparamagnetic microspheres was prepared and used as a biocatalyst to catalyze esterification reactions in diverse solvents and reaction systems. The results showed that the immobilized lipase had over 2-fold higher activities in higher log P value solvents. An exponential increase of lipase activity against log P of two miscible solvent mixtures was observed for the first time. Both free and immobilized lipase achieved its maximum activity at the range of water activity ( aw) 0.5,0.8 or higher. At aw 0.6, the immobilized lipase exhibited markedly higher activities in heptane and a solvent-free system than did the native lipase. In multicompetitive reactions, the alcohol specificity of the lipase showed a strong chain-length dependency, and the immobilized enzyme exhibited more preference for a longer-chain alcohol, which is different from previous reports. The immobilized lipase showed higher specificities for butyric acid and the medium-chain-length fatty acids (C8,C12). Then, the immobilized lipase was extended to solvent-free synthesis of glycerides from glycerol and fatty acids. Recovered by magnetic separation, the immobilized lipase exhibited good reusability in repeated batch reaction, indicating its promising feature for biotechnology application. [source]

Development of the extended parametric meshless Galerkin method to predict the crack propagation path in two-dimensional damaged structures

ABSTRACT The parametric meshless Galerkin method (PMGM) enhances the promising features of the meshless methods by utilizing the parametric spaces and parametric mapping, and improves their efficiency from the practical viewpoints. The computation of meshless shape functions has been usually a time-consuming and complicated task in the meshless methods. In the PMGM, the meshless shape functions are mapped from the parametric space to the physical space, and therefore, the necessary computational time to generate the meshless shape functions is saved. The extended parametric meshless Galerkin method (X-PMGM) even improves the parametric property of the PMGM by incorporating the partition of unity concepts. In this paper, the development of the X-PMGM is extended by incorporating a crack-tip formulation in X-PMGM for fracture analysis and prediction of crack propagation path in the damaged structures. In this formulation, meshless shape functions are enriched by discontinuous enrichment function as well as crack-tip enrichment functions. The obtained results show that the predicted crack growth path is in good agreement with the experimental results. [source]

Alpha-methylacyl-CoA racemase: a multi-institutional study of a new prostate cancer marker

Z Jiang
Aim :,To test whether ,-methylacyl-CoA racemase (AMACR) is a sensitive and specific marker of prostate cancer. Methods and results :,The expression levels of AMACR mRNA were measured by real-time polymerase chain reaction. A total of 807 prostatic specimens were further examined by immunohistochemistry specific for AMACR. Quantitative immunostaining analyses were carried out by using the ChromaVision Automated Cellular Imaging System and the Ariol SL-50 Imaging System, respectively. AMACR mRNA levels measured in prostatic adenocarcinoma were 55 times higher than those in benign prostate tissue. Of 454 cases of prostatic adenocarcinoma, 441 were positive for AMACR, while 254 of 277 cases of benign prostate were negative for AMACR. The sensitivity and specificity of AMACR immunodetection of prostatic adenocarcinomas were 97% and 92%, respectively. Both positive and negative predictive values were 95%. By automatic imaging analyses, the AMACR immunostaining intensity and percentage in prostatic adenocarcinomas were also significantly higher than those in benign prostatic tissue (105.9 versus 16.1 for intensity, 45.7% versus 0.02% and 35.03% versus 4.64% for percentage, respectively). Conclusions :,We have demonstrated the promising features of AMACR as a biomarker for prostate cancer in this large series and the potential to develop automated quantitative diagnostic tests. [source]

Advanced 4-node tetrahedrons

Rong Tian
Abstract Tetrahedral elements are indispensable to complex finite element structural analysis. Two existing and two newly developed advanced 4-node tetrahedrons are studied in this paper. The existing elements that use complicated displacement fields are significantly simplified. The spurious zero-energy modes typical of all these elements are identified to be rigid-body-alike modes and are found to be naturally suppressible, making it possible to avoid any stabilization techniques and unknown parameters in formulation. Through the simplified form, we connect these four tetrahedrons and view them in a general framework of the partition-of-unity-based approximation. This general view allows us to reveal many promising features of the newly developed tetrahedrons by comparing them with their existing counterparts: the newly developed tetrahedrons have straightforward formulation, no unsuppressed zero-energy modes, no stabilization required, no unknown parameters contained, and a high consistency in implementation, in addition to good accuracy and extremely straightforward mesh generation. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Digital storytelling: A new player on the narrative field

Marsha Rossiter
Digital stories add a multimedia dimension to narrative. The authors highlight some of the most promising features of digital storytelling for adult learning. [source]

Dielectric and magnetic properties of citrate-route-processed Li,Co spinel ferrites

Nutan Gupta
Abstract Cobalt-substituted lithium ferrites (with general composition Li0.5,x /2CoxFe2.5,x /2O4, where x = 0.0, 0.2, 0.4, 0.5 and 0.6) were prepared at lower processing temperatures (,600 °C) by the citrate route. The single-phase spinel structure was confirmed by X-ray diffraction. The average particle size of calcined powders calculated by the Scherrer formula is estimated to be 8,90 nm, whereas an average particle size of ,20 nm is observed from TEM for Co concentration x = 0.5. Average grain sizes from SEM micrographs of pellets sintered at 1000 °C (1 h) are observed to be 0.5,1 ,m, much smaller than the size reported for the standard ceramic method (2.1,6.8 ,m). The experimental density is observed to be 3.59,4.47 gm/cm3, which is greater than 85% of the densities evaluated from XRD. Compared with the standard ceramic method, lower dielectric constant (10,103) and higher dc resistivity (105,1010 , cm) is observed for Li,Co ferrites prepared by the citrate route. Improved magnetic properties, such as higher saturation magnetization (38,79 emu g,1) and Curie temperature (535 to 620 °C) are also investigated for the citrate-route-processed samples. These results demonstrate promising features of Li,Co ferrites in microwave applications. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Analytical Model for Predicting Thermal Bridge Effects due to Vacuum Insulation Panel Barrier Envelopes,

BAUPHYSIK, Issue 1 2008
Martin Tenpierik ir. arch.
Because of a necessity for sustainability and thus for a reduction of the amount of primary energy generated with fossil fuels, vacuum insulation panels (VIP) have recently caught the attention of practitioners in the building industry. The reduction of layer thickness may be considered among the most promising features for large-scale application of VIPs in buildings. The high barrier laminate (or casing) with relatively high thermal conductivity envelops the core material, thus introducing a thermal bridge at the panel edges and corners. Especially for barrier laminates containing ,thick' metal foils, the thermal bridge effect needs to be considered thoughtfully. In this contribution analytical models are presented which on the one hand allow rapid estimation of the VIP's overall thermal performance and on the other hand show the influence of material and geometric parameters on this performance. The analytical models are validated through numerical simulations. Rechenmodell zur Vorhersage von Wärmebrückeneffekten an der Hülle aus Hochbarrierefolien von Vakuum-Isolations-Paneelen (VIP). Aufgrund der Notwendigkeit von nachhaltigem Bauen und Energieeinsparung wird zunehmend der Einsatz von Vakuum-Isolations-Paneelen (VIP) zur Wärmedämmung im Bauwesen erwogen, insbesondere ist damit die erhebliche Reduzierung der Wärmedämmschichtdicke möglich. Die Umhüllung aus Hochbarrierefolien erfordert allerdings die Berücksichtigung der Wärmebrückenwirkung. Der vorliegende Beitrag stellt Berechnungsmodelle vor, welche einerseits die schnelle Abschätzung des thermischen Verhaltens von VIP-Elementen ermöglichen und andererseits den Einfluss der Geometrie und Konstruktion der Elemente aufzeigen. Die Berechnungsmodelle wurden anhand von Simulationen validiert. [source]