Application of numerical simulation for wear analysis of warm forging die

Warm forging process has better forming precision than hot forging process and has better formability than cold forging. But warm forging die sustains higher temperature and working pressure, the die wear is faster than those of hot forging and cold forging. The purpose of this research is to combine the experimental techniques, wear model and numerical simulation method to predict the wear of warm forging die. The non-isothermal ring compression test was adopted to estimate the friction coefficient in different temperatures and the on-line temperature recording system was setup to correct the heat transfer coefficient of the interface. The wear coefficients in different temperatures were acquired from high temperature wear experiment. Finally, the Archard wear theory and DEFORM, a FEM code, were used to analyze the warm forging of automotive transmission outer-race and predict the die wear condition.     

Development of low‐fat mayonnaise containing polysaccharide gums as functional ingredients

BACKGROUND: The objective of this study was to develop a low‐fat (LF) mayonnaise containing polysaccharide gums as functional ingredients. Xanthan gum (XG, 15 g kg^?1), citrus fiber (CF, 100 g kg^?1) and variable concentration of guar gum (GG) were used to formulate the optimum ratios of polysaccharide gums as fat replacers. The fat content in LF mayonnaise was reduced to 50% if compared with full‐fat (FF) mayonnaise, and the products still maintained ideal rheological properties. RESULTS: The rheological parameters showed that there were no (P > 0.05) differences in yield stress, viscosity and flow behavior index between XG + 10 g kg^?1 GG, CF + 5 g kg^?1 GG and FF control. LF mayonnaises had lower caloric values and higher dietary fiber content than the FF counterpart. Scanning electron microscopy (SEM) micrographs illustrated that the network of aggregated droplets in LF treatments contained a large number of interspaced voids of varying dimensions. Furthermore, in a comparison of sensory evaluation of LF treatments with commercial and our FF mayonnaises, there were no (P > 0.05) differences in any sensory scores among XG + 10 g kg^?1 GG control. CONCLUSION: This study shows that XG + 10 g kg^?1 GG and CF + 5 g kg^?1 GG could be used in LF mayonnaise formulations based on its multiple functions on processing properties. Copyright © 2010 Society of Chemical Industry     

A divide-and-conquer-based algorithm for automatic simulation vector generation

Testbenches play one of the most important roles in simulation-based design verification. Given a simulation scenario, a testbench provides specific vectors to simulate the design, then collects responses from the design to monitor whether the simulation has satisfied the scenario. The major bottleneck in writing testbenches is generating valid simulation vectors. Many current automatic-vector-generation methods focus on exploring a design's state space. Due to memory or runtime limitations, these methods cannot keep up with the rapid growth of design complexity. We propose a novel algorithm based on the divide-and-conquer paradigm that helps these methods decompose the design's complexity. The algorithm uses a partitioning method that recursively divides a design into smaller, more manageable components. Other approaches handle the divided components while maintaining the entire design's proper functioning. Random simulation generates sets of simulation vectors by randomly assigning the logic values to the design's primary inputs (Pis) one cycle at a time. Unlike random simulation, which uses only a single trace, symbolic solvers attempt to simultaneously enumerate all possible primary inputs to explore the entire state space. They typically use binary decision diagrams (BDDs) or satisfiability (SAT) solvers as their core engine.     

Low-cost and low-electromagnetic-interference packaging of optical transceiver modules

The low-cost and low-electromagnetic-interference (EMI) packaging of optical transceiver modules employing housings of plastic composites are developed and fabricated. Optical transceiver modules fabricated by the plastic composites with transmission rates of 1.25 and 2.5 Gb/s are tested to evaluate the electromagnetic (EM) shielding against emitted radiation from the plastic packaging. The results show that these packaged optical transceiver modules with their high shielding effectiveness (SE) are suitable for use in low-cost and low-EMI Gigabit Ethernet lightwave transmission systems. By comparison of cost, weight, and shielding performance for optical transceiver modules fabricated by the housings of nylon and liquid-crystal polymer with carbon fiber filler composites, woven continuous carbon fiber (WCCF), and nanoscale hollow carbon nanocapulses (HCNCs) epoxy composites, the WCCF composite shows lower cost, lighter weight, and higher EM shielding than the other types of composites. Future studies may develop the low-cost and low-EMI optical transceiver modules using nanoscale HCNCs that have the combination of excellent physical and mechanical properties, light weight, and thinness compared with the conventional fabrication techniques.     

High reliability of AlGaInP LED's with efficient transparentcontacts for spatially uniform light emission

The indium-tin oxide (ITO) films with low sheet resistance and conducting transparency have been used on the AlGaInP double-heterostructure orange light-emitting diodes (LED's) to improve the light extraction from the LED surface and device reliability. The orange LED's with ITO films exhibit a light output power of 1 mW at 50 mA, which corresponds to an external quantum efficiency of 1.1%. They can operate stably for more than 3000 h at 20 mA and 25°C without any degradation     

Evaluation of the Coulter MAXM. Differential leukocyte count and left-shift alarm

Affective instability in borderline personality disorder is due to a marked reactivity to environmental events. The present study focused on the relationship between affective instability and impulsivity in personality disorder. It used an experimental approach in the form of an affect-stimulation design based on the presentation of a short story which allowed for an analysis of affective responses in regard to quality, intensity, and alterations over time. Impulsive personalities showed a strong intensity of affective responses us well as a tendency towards rapid affect alterations supporting the theory of poor affect regulation in subjects with impulsive self-harming behaviour. Results suggest that affective instability is a crucial part of impulsive personality functioning.     

General formula for bending beam determination of case II diffusion in polymer-containing bilayer structures

An exact formula has been presented to correlate the bending curvature cariation ratio, Ω, of any given bilayer structure comprising a solvent-swellable polymer layer with diffusion time, t, under case II diffusion. The formula can be used to determine the diffusion front velocity, v, for layered structures comprising a thick polymer film on a thin substrate or vice versa when subjected to solvent diffusion. According to this formula, there is little effect from plasticization or swelling in the transverse direction on the diffusion curve of Ω vs. t if the polymer layer to be investigated is relatively thin and its intrinsic hygroscopic strain ratio is less than unity. By using this model, the diffusion of N-methyl pyrollidinone (NMP) in a 18-μm rodlike pyromellitic dianhydride p-phenylene-diamine (PMDA-PDA) polymide film, coated on a 75-μm silicon substrate, is found to be case II with a diffusion front velocity of 1.84 × 10^-7 cm/s. © 1995 John Wiley & Sons, Inc.     

Branched diphenylsilane derivatives containing electronically isolated indolyl moieties as host materials for blue organic light emitting diodes

Branched diphenylsilane derivatives with pendent indolyl fragments were synthesized and characterized. The compounds show high thermal stability with thermal decomposition starting at temperatures above 367 °C and ability to form glasses with glass-transition temperatures of 53-58 °C. The electron photoemission spectra of the layers of the synthesized compounds showed ionization potentials of ca. 5.85 eV. The derivatives were tested as host materials in phosphorescent OLEDs with iridium(III)[bis(4,6-difluorophenyl)-pyridinato-N,C2′]picolinate as the guest. The device with the host derivative containing four electronically isolated indolyl fragments exhibited the best overall performance with maximum current efficiency of about 12 cd/A.     

Soil dioxins levels at agriculture sites and natural preserve areas of Taiwan

In this study, agriculture soil in Taiwan has been sampled and analyzed to determine the background level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DF) in the agricultural and nature preserve areas. Another objective is to investigate relationship between soil characteristics and air deposition in Taiwan. The results indicate that in nature preserve areas the topsoil shows an extraordinary profile of PCDD/DF compared to that in the air deposition. The PCDD/DF levels of the low-contaminated agricultural soils are compatible with those of the nature preserves soils. However, in the highly-contaminated agricultural soils, there is an abrupt jump in their concentrations, 10-100 times higher. The overall I-TEQ values of the background topsoils range from 0.101 to 15.2 ng I-TEQ/kg. Near industrial/urban areas in Taiwan the PCDD/DF are slightly higher compared to those in the low concentration group. Typically, the PCDD/DF background values found in this survey fall in the 90% confidence interval and can thus, be deemed the background levels in Taiwan. Ninety-five percent of these data are below the European and American soil standard of 10 ng I-TEQ/kg d.w. The PCDD/DF profile with one neighborhood soil sample was shown no significant difference.     

Dengue: a re-emerging disease. A clinical and epidemiological study in 57 Spanish travelers

Dengue infection is nowadays considered a re-emergent disease. It has a worldwide tropical and subtropical distribution. The dengue virus in a member of the flavivirus family composed by 4 different serotypes. The virus is transmitted by mosquitos of the Aedes genus. With the increment of travels to the endemic areas, dengue is now observed frequently in our country. We analyzed 57 patients, 30 with imported dengue (ID) and 27 with dengue fever suffered during the trip (DDT). This series is compared with other published ones and a review of the subject is presented. Patients with ID followed a protocol as a febril syndrome returning from the tropics. Dengue was diagnosed through a compatible clinico-epidemiological history, the absence of other ferbil illness and positivity of specific serology. All patients had travelled to endemic areas (Central America 28 cases, Indian subcontinent 15, South-East Asia 10, South America 2, West Africa one, and Pacific one). The following were the most important clinical characteristics: fever and asthenia (100%), headache (98%), mialgia (84%), arthralgia (72%), morbilliform rash (61%) and retroocular pain (65%). For ID cases, the most helpful analitical results were: leucopenia (70%), reactive lymphocytes in peripheral blood smear (70%), thrombocytopenia (70%), and increased hepatic enzymes ALAT (53%), ASAT (63%) and LDH (100% in the 7 patients tested for this enzyme). Dengue must be included in differential diagnosis of fever in patients coming back to travels to tropical areas.