Optimization of Enzymatic Process Condition for Protein Enrichment,Sugar Recovery and Digestibility Improvement of Soy Flour

Soy protein is a valuable nutritional supplement for food and animal feed. While protein constitutes ~50 % of defatted soy flour (SF), it coexists with complex carbohydrates (30–35 %) which may have anti‐nutritional effects. An enzymatic process can remove the carbohydrate and produce protein‐enriched soy products. The hydrolysate with monomerized carbohydrates is valuable fermentation feedstock. In this study, Aspergillus niger and Trichoderma reesei enzymes were compared for use in the process. Effects of pH (3.2–6.4), temperature (40–60 °C), enzyme‐to‐SF ratio (0–2 ml/g) and SF loading (150–350 g/l) were evaluated for the enzymatic conversion of SF carbohydrate to reducing sugar (Y_RS) and total soluble carbohydrate (Y_TC) in the hydrolysate. Effects of these single factors and interactions between factors were investigated. Optimal pH and temperature were similar for both enzymes: pH 4.8 and 50–51 °C for Y_TC, and pH 5.1–5.2 and 48–51 °C for Y_RS. The two enzymes also gave similar protein contents in resultant soy protein concentrates, i.e., 74–75 % with 2 ml/g enzyme broth and 150 g/l SF, which were higher than the 64–68 % protein in commercial concentrates. A. niger enzyme was significantly more effective in carbohydrate conversion, achieving Y_RS = 75 % and Y_TC = 78 % with 2 ml/g enzyme and 150 g/l SF, higher than the Y_RS (30 %) and Y_TC (64 %) obtained with T. reesei enzyme. Monomerization was essentially complete in hydrolysate produced with A. niger enzyme.     

Signaling techniques that increase the understandability of expository prose.

In 2 experiments, 102 15–17 yr old high school students read and listened to either a signaled or nonsignaled expository passage. The signals consisted of preview sentences, underlined headings, and logical connective phrases. The results show a pattern in which the signaled groups performed better on recall of conceptual information and on generating high quality problem solutions, whereas the nonsignaled groups excelled on recall of information from the beginning and end of the passage and on generating low quality problem solutions. These results suggest that signaling is effective in modifying students' reading strategies. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of the effect of reflow time and temperature on Cu–Sn intermetallic compound layer reliability

In terms of various reflow time and temperature, an analysis of Cu–Sn intermetallic compound (IMC) layer reliability is presented in this paper. Temperature cycling test data reported in existing publications for the solder paste material of 63Sn/37Pb eutectic alloy is used to model the probability distribution functions of solder joint lifetime due to the IMC layer fatigue. The relationship of the IMC layer thickness as a function of reflow time and temperature is studied. A reliability and mean time to failure function of the IMC layer in terms of various reflow time and temperature are presented. Calculation suggests that to achieve a higher IMC layer reliability, a shorter reflow time and a lower reflow temperature should be used, while lowering reflow temperature may be more efficient than controlling reflow time. In general, a reflow temperature ranged by 240–280 °C should be avoided. For a specified reliability goal, how to choose proper reflow time and temperature is discussed.     

Prediction of rate-independent constitutive behavior of Pb-free solders based on first principles

This paper presents a methodology for the theoretical estimation of rate-independent plastic constitutive properties of Pb-free solders using three approaches. The first approach is based on a nonlinear effective medium theory (NEMT) that is scale independent. The second approach is based on the micromechanics and physics of plastic slip in heterogeneous alloys (henceforth called the physical model). This approach explicitly includes microstructural features such as grain size, particle size etc. The third approach is a combination of NEMT and the physical model. Our estimates involve no adjustable calibration parameters and are based on first principles and constituent properties. Parametric studies are conducted to show that the physical model is more effective for small particles sizes (nanoscale <100 nm), small particle spacing (/spl sim/ nm range) and low volume fractions (<2.5%); while NEMT performs well for large volume fractions (>5%), large particle sizes (micron size) and large particle spacing (micron scale). The proposed hybrid approach, however, appears to be valid for a wider range of particle sizes and volume fractions. Limited comparison with experimental data is also made and implications of our work in the economical design of novel Pb-free solders is discussed.     

Reliability block diagram simulation techniques applied to the IEEE Std. 493 standard network

This is one of a series of papers discussing the application and accuracy of different analysis techniques supporting the determination of industrial and commercial power system reliability and availability. There is a need recognized in the power industry to identify and utilize a standard tool, or a set of tools, to analyze the reliability of power systems. Historically, the results of applying different reliability methodologies and tools varied significantly, and comparisons were difficult. The Reliability Analysis Techniques Working Group of the Gold Book (IEEE Std. 493-1997) developed a standard network to enable comparison of analytical techniques. This paper describes the approach of simulations via reliability block diagrams as applied to the Gold Book standard network. Reliability indexes of the load points are presented, and are compared with ones obtained from other techniques in the series to determine the accuracy.