Transient forced convection in the entrance region of porous concentric annuli

The problem of transient laminar forced convection in the entrance region of a porous concentric annulus with developing thermal boundary layer is solved numerically by the finite difference technique. The hydrodynamic behaviour of the flow is assumed to be steady and fully developed, and both Darcian and non-Darcian effects on the flow are considered.     

Analysis of roller chain sprocket pressure anglesL'analyse des angles de pression d'un pignon avec une chaine a rouleax

An analysis is presented for determining the effect of pitch difference on roller chain articulation angles and pressure angles. Basic formulas and strategies are given for locating contact points. Results are presented and compared with those from a graphical solution.     

Round-Robin Testing of Three Phase Padmount Transformers

This paper addresses the accuracy of 3-phase transformer loss testing with particular attention to the reliability of manufacturers' certified loss test results. Seven three-phase padmounts, one from each of seven different manufacturers, were used in a round-robin test program. In addition to their original production tests, each of the seven manufacturers performed loss tests on the entire group of transformers. The results of the program indicate an uncomfortably wide range of results.     

Neck-tongue syndrome: a case caused by atlanto-axial osteoarthritis of tuberculous origin

The neck-tongue syndrome involves paroxystic pain in the nape of neck associated with sensitive disorders of the ipsilateral hemitongue aggravated by movements of the nape of neck. It is attributed to relating fibers of proprioceptive origin which pass through the great nervus hypoglossus from the second cervical stria. The lingual pseudoathetosis is also reported to a proprioceptive deafferentation of the tongue. In most of cases, no etiology has been found. We report a case of neck-tongue syndrome with pseudoathetosis, related to an atloaxoid osteoarthritis of tuberculous origin.     

Comparative study of conventional and micro WEDM based on machining of meso/micro Sized Spur Gear

This paper discusses the comparison of micro machining process using conventional and micro wire electrical discharge machining (WEDM) for fabrication of miniaturized components. Seventeen toothed miniaturized spur gear of 3.5 and 1.2 mm outside diameter were fabricated by conventional and micro WEDM respectively. The process parameters for both conventional and micro WEDM were optimized by preliminary experiments and analysis. The gears were investigated for the quality of surface finish and dimensional accuracy which were used as the criteria for the process evaluation. An average surface roughness (R_a) of 50 nm and dimensional accuracy of 0.1–1 μm were achieved in micro WEDM. Whenever applied conventional WEDM for meso/micro fabrication, a R_a surface roughness of 1.8 μm and dimensional accuracy of 2–3 μm were achieved. However, this level of surface roughness and dimensional accuracy are acceptable in many applications of micro engineering. A window of conventional WEDM consisting of low energy discharge parameters is identified for micromachining.     

Increased In Vitro and In Vivo Digestibility of Soy Proteins by Chemical Modification of Disulfide Bonds

To improve protein digestibility of aqueously extracted soy proteins, an effective chemical treatment under mild conditions is needed. Soy proteins, including storage protein glycinin and antinutritional factors such as trypsin inhibitors, are rich in disulfide bonds. Reduction of these disulfide bonds by incubating soy proteins with sodium sulfite and sodium metabisulfite at 55 °C showed no net increase of free sulfhydryl groups after dialysis to remove the residual reducing agent. However, the in vitro digestibility measured by trypsin hydrolysis using the pH-Stat method was significantly increased. Sodium metabisulfite (SMBS) was more effective in increasing in vitro digestibility than sodium sulfite at the same molar concentration. The digestibility of soy protein treated by 0.5 mmol SMBS/g soy flour at 55 °C was more than doubled compared to that of the control without reduction treatment. Large-scale testing of soy proteins treated with SMBS for an in vivo animal feeding study showed similar in vitro digestibility by trypsin, e.g., the degree of hydrolysis of the treated sample was 8.5% compared to 1.6% of the control. These soy proteins were further evaluated using a chick growth model. The protein efficiency ratio (PER) increased by 57% when the chicks fed SMBS-treated soy were compared to the chicks fed raw soy flour. SMBS-fed chicks did not display any pancreatic hypertrophy compared to those fed with raw soy control. These results indicate that there is great potential to use safe chemicals and mild temperature to inactivate the antinutritional factors in soybeans and thus improve digestibility of soy proteins that are extracted with low-temperature aqueous process.     

Ratio of oxygen and nitrogen Raman cross sections in the ultraviolet

We report measurements of the ratio of oxygen and nitrogen Raman cross sections for excitation wavelengths between 220 and 290 nm. These measurements confirm strong enhancement of the oxygen Raman cross section in this region.     

Progressive Collapse Analysis of Cable-Stayed Bridges

Journal of Failure Analysis and Prevention - Several codes have proposed guidelines to prevent progressive collapse. Although most of these standards are in progress, few recommendations for...     

Training radial basis function networks using biogeography-based optimizer

Training artificial neural networks is considered as one of the most challenging machine learning problems. This is mainly due to the presence of a large number of solutions and changes in the search space for different datasets. Conventional training techniques mostly suffer from local optima stagnation and degraded convergence, which make them impractical for datasets with many features. The literature shows that stochastic population-based optimization techniques suit this problem better and are reliably alternative because of high local optima avoidance and flexibility. For the first time, this work proposes a new learning mechanism for radial basis function networks based on biogeography-based optimizer as one of the most well-regarded optimizers in the literature. To prove the efficacy of the proposed methodology, it is employed to solve 12 well-known datasets and compared to 11 current training algorithms including gradient-based and stochastic approaches. The paper considers changing the number of neurons and investigating the performance of algorithms on radial basis function networks with different number of parameters as well. A statistical test is also conducted to judge about the significance of the results. The results show that the biogeography-based optimizer trainer is able to substantially outperform the current training algorithms on all datasets in terms of classification accuracy, speed of convergence, and entrapment in local optima. In addition, the comparison of trainers on radial basis function networks with different neurons size reveal that the biogeography-based optimizer trainer is able to train radial basis function networks with different number of structural parameters effectively.