Phase Transitions of Wheat Starch-Water Systems Containing Polydextrose

Equivalent concentrations of polydextrose and sucrose had similar effects on phase transitions of wheat starch-water systems. Onset and peak gelatinization temperatures were increased similarly with the two solutes. This was true with varied water:starch ratios, varied concentrations of solute, and for batters prepared with the two solutes. Acesulfame K, cyclamate, and saccharin at low levels, as might be used in food products, had little effect on phase transitions of starch-water-solute systems.     

PREDICTING INTERNAL TEMPERATURE RESPONSE TO CONDUCTION-HEATING OF ODD-SHAPED SOLIDS

Heat penetration experiments were carried out in a hot water bath with small blocks of a solid polycarbonate material cut into various shapes (cylinder, cube and oval) to obtain heat penetration factors for each shape. These factors, along with characteristic dimensions from the odd shapes were then used in the finite cylinder heat transfer model to predict accurately the temperature at the center of each block in response to measured dynamic bath temperatures. Results showed sufficiently good agreement between predicted and measured center temperature profiles to justify use of the finite cylinder model for rapid evaluation of process deviations in thermal processing of foods in odd-shaped containers.     

Grain growth of copper films prepared by chemical vapour deposition

Copper films having thickness 600 nm were prepared on TiN using chemical vapour deposition (CVD). The deposited films were annealed at various temperatures (350–550°C) in Ar and H₂(10%)-Ar ambients. The changes in the grain size of the films upon annealing were investigated. Annealing in an H₂(10%)-Ar ambient produced normal grain growth; annealing in an Ar ambient caused grain growth to stop at 550°C. The grain size followed a monomodal distribution and the mean size increased in proportion to the square root of the annealing time, indicating the curvature of the grain is the main driving force for grain growth. Upon annealing at 450°C for 30 min in an H₂(10%)-Ar ambient, the average grain size of the film increased from 122 nm to 219 nm, and the resistivity decreased from 2.35 μΩ cm to 2.12 μΩ cm at a film thickness of 600 nm. This revised version was published online in July 2006 with corrections to the Cover Date.     

An agile manufacturing workcell design

This paper introduces a design for agile manufacturing worked Is intended for light mechanical assembly of products made from similar components (i.e., parts families). We define agile manufacturing as the ability to accomplish rapid changeover from the assembly of one product to the assembly of a different product. Rapid hardware changeover is made possible through the use of robots, flexible part feeders, modular grippers, and modular assembly hardware. The division of assembly, feeding, and unloading tasks between multiple robots is examined with prioritization based upon assembly time. Rapid software changeover will be facilitated by the use of a real-time, object-oriented software environment utilizing graphical simulations for off-line software development. An innovative dual VMEbus controller architecture permits an open software environment while accommodating the closed nature of most commercial robot controllers. These agile features permit new products to be introduced with minimal downtime and system reconfiguration.     

Gelatinization and Liquefaction of Starch with a Heat Stable α-Amylase

Sweet potato and corn starches were gelatinized and liquefied to dextrose equivalent (DE) 10 in a steam-jacketed kettle or in a twin-screw extrusion cooker in a single step process with a heat stable ex-amylase. The time required to gelatinize and liquefy 20% starch slurries in a kettle at 95°C was 45 to 50 sec. Starch powder (10 kg/hr) and water (2-6 kg/hr) were fed to an extrusion cooker to adjust the moisture contents of the starch from 20 to 55% (wet basis) and gelatinized and liquefied to DE 10 at a barrel temperature of 120°C or above with 2 to 3% (w/w) a-amylase added. The optimum conditions for the operation were to feed starch with water to maintain 50% moisture and 2% heat stable a-amylase at a barrel temperature of 120°C.     

Separation of Immunoglobulin G from Cheddar Cheese Whey by Avidin-Biotinylated IgY Chromatography

High-purity immunoglobulins (Ig), which may be useful for immunologic supplementation of food products, were isolated from Cheddar cheese whey in a one-step process using avidin-biotinylated yolk immunoglobulin (IgY) column chromatography. Yolk antibodies specific to bovine IgG (IgY_IgG) were biotinylated with biotinyl amido-hexanoic acid-N-hydroxy-sulfo-succinimide ester without any notable effect on antigen-binding activity, and coupled to immobilized avidin columns. The resulting avidin-biotinylated IgY_IgG columns, with binding capacity of 50–55% (w/w percent ratio of IgG to immobilized IgY_IgG), were used for specific binding of IgG from cheese whey. Elution with a commercially available eluent (Actisep) or 0.1 M glycine-HCl buffer at pH 2.8 yielded IgG with purity of 99% by radial immunodiffusion.     

Canola Phytase: Isolation and Characterization

Two phytase isoenzymes were isolated from 8-day germinated canola cv Regent. Gel filtration chromatography of an ammonium sulfate fractionated extract on Sephadex G-100 produced one peak with phytase activity. The phytase fraction was separated into two isoenzymes by DEAE-cellulose chromatography. The optimum pH was 4.5–5.0 and 5.0 for the phytase isoenzymes 1 and 2, respectively. Both isoenzymes exhibited maximum activity at 50°C. Km values at pH 5.0 were 0.36 and 0.25 mM for phytase 1 and 2 isoenzymes, respectively, while molecular weight determination showed both fraction were identical with a molecular weight of 70,100 ± 4,000 daltons.     

微波辐射辅助柠檬酸络合法制备的Ho3+/Tm3+/Yb3+共掺杂CaWO4的白光性能（英文）

采用微波辐射辅助柠檬酸络合法制备Ho3+/Tm3+/Yb3+共掺杂CaWO4纳米晶升频转换荧光粉。将柠檬酸络合物前驱体在300~700°C热处理3 h。Ho3+/Tm3+/Yb3+共掺杂CaWO4C在400°C时开始结晶,在600°C时结晶完成。经600°C热处理的Ho3+/Tm3+/Yb3+共掺杂CaWO4主要呈球形,且形态均匀。在980 nm的激光激发下,Ho3+/Tm3+/Yb3+共掺杂CaWO4纳米晶出现肉眼可见的明亮的白色升频转换发射,这种现象来自Tm3+的475 nm蓝光发射以及Ho3+的543 nm绿光和651 nm红光发射。通过调整Tm3+和Ho3+的浓度可以控制Ho3+/Tm3+/Yb3+共掺杂CaWO4的CIE色度图从冷到暖白色之间变化。讨论了Tm3+和Ho3+浓度对升频转换光性能的影响以及与激光泵功率相关的影响机制。     

纳/微异构型钙钛矿氧化物电极在固体氧化物燃料电池的研究进展

开发高效、稳定、廉价的钙钛矿氧化物电极材料是固体氧化物燃料电池(SOFC)进一步商业化发展的关键。目前,研究重点仍集中在解决阳极积碳、硫毒化以及阴极氧还原(ORR)低温性能不佳等问题。最近,有研究报道,一些易还原过渡金属元素掺杂的钙钛矿可以在还原气氛中原位析出该金属并以纳米颗粒的形式"镶嵌"在钙钛矿表面形成"纳米金属–钙钛矿"复合结构。该方法制备的材料具有性能高、抗积碳能力强、可再生性好等优点。从钙钛矿氧化物本体的选择、A/B位掺杂、缺陷调整、以及拓扑离子交换、相变诱发等方面,总结了近年来关于构建纳米(析出金属颗粒)微米(钙钛矿氧化物母体)异质结构(统称纳微异构)钙钛矿氧化物纳米纤维复合电极的研究。此外,总结了具有纳米纤维状形貌的钙钛矿氧化物电极及其结构对于SOFC性能、稳定性的影响,最后提出了该类纳微异构材料的优势、不足和展望。     

Effects of honing treatment on AIP-TiN and TiAlN coated end-mill for high speed machining

The objective of this work is to compare the tool performance of TiN and TiAlN coated carbides end-mills deposited by an arc ion plating (AIP) method, using honing treatment to polish the cutting edge surface sleekly. The curve of surface roughness versus honing time showed a rapid improvement initially and thereafter became steady, manifesting a saturation effect. The optimal honing time related to surface roughness was determined to be approximately 20 s. As the surface roughness increased, the critical loads reduced. At an average surface roughness (Ra) of 0.028 μm, the highest critical loads of TiN and TiAlN coating layers were 98 and 114 N, respectively. Tool performances of uncoated and coated tools were conducted under high speed machining (HSM) of AISI D2 cold-worked die steel (62 HRC). Consequently, the TiAlN coated end-mill using honing treatment showed excellent tool life under HSM conditions.