Transient Inclusion Evolution During Modification of Alumina Inclusions by Calcium in Liquid Steel: Part II. Results and Discussion

The formation of intermediate reaction products after calcium addition to aluminum-killed steel was studied. Steel samples were taken from laboratory and industrial heats before and at various times after calcium treatment. Inclusions were characterized by automated and manual scanning electron microscopy and X-ray microanalysis of polished cross sections and inclusions extracted by dissolution of the steel. Industrial and laboratory melts containing more than 40 parts per million (by mass) of dissolved sulfur showed calcium sulfide as the main reaction product after calcium injection, with calcium aluminates appearing later. It is proposed that the calcium aluminates are formed by reaction between the calcium sulfide and the alumina. A laboratory heat containing 7 parts per million of sulfur showed calcium oxide as the main initial calcium reaction product. A simple mechanism is proposed for the modification of alumina inclusions by calcium, considering transient CaO and CaS formation.     

Categorically defined targets trigger spatiotemporal visual attention.

Transient attention to a visually salient cue enhances processing of a subsequent target in the same spatial location between 50 to 150 ms after cue onset (K. Nakayama & M. Mackeben, 1989). Do stimuli from a categorically defined target set, such as letters or digits, also generate transient attention? Participants reported digit targets among keyboard symbols in a changing array of 8 items. When 1 target preceded a second target in the same location at a stimulus onset asynchrony of 107 ms (but not 213 ms), the second target was reported more often than in a condition in which there was no leading target. When the 2 targets were at different locations, report of the second target was impaired. With both letters and digits as targets, the enhancement effect was shown not to be due to category priming. Critically, the attentional benefit was present whether or not participants reported the leading target. Transient attention, contingent attentional capture, popout, and Lag 1 sparing in the attentional blink may involve a common mechanism for orienting processing resources towards salient and task relevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The nature of choice in mass customized house building

There is a need to explore the actual uptake of specification options by clients in the context of the self-build housing industry. In so doing all the components in a house that can be customized were categorized so as to highlight the features that must be customizable and those that can be standardized. Through a longitudinal study of a German house builder, data from 16 projects over a 35-year time horizon have been collected. The extent of choice made in these projects has been determined by comparing the original standard building specification with the actual finalized fit-out specification of the project. In scrutinizing the collected data it became apparent that the number of changes made by the clients increased considerably over the timespan studied. More importantly, clients appreciated the freedom of choice as they were prepared to spend increasing amounts on customization. In particular specification options were made in the sanitary, internal design and façade categories. Moreover the results revealed that offering a high degree of choice is appropriate for most, but not all, components for the case house builder. Key areas for choice include those relating to sanitary ware and the façade.     

高可靠性RF技术服务于无线和RFID市场

近几年,无论是手机代表的无线移动网络及其基础设施,还是以蓝牙(Bluetooth)、无线局域网(WLAN)、Zigbee等长、短距离的无线通信技术,或者是WiMax、RFID等面向特定应用的专门技术,给人们带来了种种方便,也在悄悄改变着产业的格局.作为各种无线技术基础的RF技术,也在不断吸纳新技术、新设计,以满足系统对于更大数据传输量、更低的功耗和成本要求、更苛刻的信号可靠性要求等挑战.从另一侧面看,由于RF技术固有的较高门坎,并非一些新手力所能及,虽然半导体产业链以厂商数量众多著称,但RF技术供应商则相对较少.     

Rapid Quantitative Measurement of Extrusion-Induced Starch Fragmentation by Automated Gel Permeation Chromatography

Gel permeation chromatography with application of the universal calibration concept was found to be a rapid and effective method for quantification of extrusion-induced starch fragmentation. This method (Timpa. J.D., J. Agr. Food Chem. 39 (1991), 270–275) employs dimethyl acetamide (DMAC) with lithium chloride to solubilize samples and automated gel permeation chromatography for fractionation. Instrumentation was equipped with a viscometer and refractometer, data was interpreted by application of the universal calibration concept. These results confirm that the largest starch molecules in corn meal (107 to 108 Daltons) were slightly prone to fragmentation. Fragments produced were primarily in the weight range of 104–107 Daltons. In addition, some smaller fragments (ranging between 5,000 and 7.500) were also generated by extrusion.     

Methanol synthesis over Cu/SiO2 catalysts

The rates of CO and CO/CO₂ hydrogenation at 4.2 MPa and 523 K are reported for a series of Cu/SiO₂ catalysts containing 2 to 88 wt.% Cu. These catalysts were prepared on a variety of silica sources using several different Cu deposition techniques. In CO/CO₂ hydrogenation, the rate of methanol formation is proportional to the exposed Cu surface area of the reduced catalyst precursor, as determined by N₂O frontal chromatography. The observed rate, 4.2×10^–3 mole CH₃OH/Cu site-sec, is within a factor of three of the rates reported by others over Cu/ZnO and Cu/ZnO/Al₂O₃ catalysts under comparable conditions. These results suggest that the ZnO component is only a moderate promoter in methanol synthesis. Hydrogenation of CO over these catalysts also gives methanol with high selectivity, but the synthesis rate is not proportional to the Cu surface area. This implies that another type of site, either alone or in cooperation with Cu, is involved in the synthesis of methanol from CO.     

Docosahexaenoic acid and other dietary polyunsaturated fatty acids suppress leukotriene synthesis by mouse peritoneal macrophages

The efficacy of individual ω-t-3 polyunsaturated fatty acids (PUFA) in altering eicosanoid synthesis in peritoneal macrophages was studied by feeding mice for 10 days a diet containing 2 wt% fat, which included 0.5 wt% ethyl esters of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or linolenic acid (LNA). Upon stimulation with calcium ionophore A23187, macrophages from these animals produced significantly lower amounts of leukotriene C₄, leukotriene B₄ and 12-hydroxyeicosatetraenoic acid, prostaglandin E₂ and 6-keto prostaglandin F_1α compared with those obtained from animals on the diets containing olive oil or safflower oil. The decrease in leukotriene synthesis was similar in the animals fed DHA, EPA or LNA diets. This depression of eicosanoids by DHA and EPA was associated with decreased levels of arachidonic acid (AA); however, LA that altered eicosanoids did not have the same effect on AA levels.     

Contribution of triglycerides from cocoa butter to the physical properties of milkfat fractions

Milkfat was separated into major chainlength fractions by solid-phase extraction. The effect on thermal behavior and texture of replacing both saturated and monounsaturated long-chain triglycerides from milkfat by long-chain monounsaturated triglycerides with an unsaturated fatty acid in thesn-2 position is reported. Increasing proportions of cocoa butter were added to fractions of short-to medium-chain triglycerides (C₂₂−C₄₄) and medium- to long-chain triglycerides (C₃₆−C₄₈) isolated from milkfat. Thermal behavior and texture of the mixtures were measured. Results indicated that long-chain monounsaturated triglycerides from cocoa butter enhanced co-crystallization and co-operative melting and did not induce polymorphic transitions upon crystallization and melting of the fractions. At 4°C, they acted as texture builder if present in proportions of more than 30%, whereas below this level, they acted as texture softeners. The effect of the long-chain monounsaturated triglycerides on the texture of fractions that melt at low temperature could not be predicted from the proportion of solid fat at that temperature. Presented at the 1995 AOCS Annual Meeting & Expo, San Antonio, Texas, May 1995.