Quality Indices for Aluminum Alloy Castings: A Critical Review

Several indices are available in the literature to assess the structural quality of cast Al alloys, especially Al-7 pct Si-Mg alloys that are based on tensile test results. Some of these indices, most notably the one developed by Drouzy et al., provide a number that necessarily does not have a physical meaning, whereas the others are a measure of what fraction of the expected tensile performance is achieved. These indices are analyzed in depth, their similarities and shortcomings are discussed in detail, and recommendations are made.     

Development and validation of a measure of academic entitlement: Individual differences in students’ externalized responsibility and entitled expectations.

Four studies present the validation of a self-report scale capturing academic entitlement, which is defined as the tendency to possess an expectation of academic success without a sense of personal responsibility for achieving that success. The Academic Entitlement scale possesses a 2-factor structure (Study 1); 10 items measure students’ Externalized Responsibility for their academic success, and 5 items measure students’ self-serving Entitled Expectations about professors and course policies. In Study 2, the Externalized Responsibility subscale correlated positively with related measures of entitlement, grandiosity, and narcissism, and it was negatively related to self-esteem, personal control, need for cognition, agreeableness, and conscientiousness. In Study 3, participants rated various responses to academic situations selected by university instructors as highly inappropriate or highly appropriate. The Academic Entitlement scale predicted students’ ratings of the appropriateness of these student behaviors as well as the likelihood that they themselves would engage in these behaviors. In a laboratory setting, individuals with high Academic Entitlement scores evaluated the researcher more negatively than those with low Academic Entitlement scores (Study 4). Practical applications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

GaAsSb: a novel material for near infrared photodetectors on GaAs substrates

We have studied the molecular beam epitaxy (MBE) growth of GaAsSb on GaAs substrates. The optical properties and composition of GaAsSb layer strongly depend on the growth temperature, the Ga growth rate, and the As and Sb fluxes and their ratios. We also report on two GaAsSb-GaAs photodiode structures operating at 1.3 /spl mu/m. The peak quantum efficiency was 54% for the GaAsSb resonant-cavity-enhanced (RCE) p-i-n photodiode and 36% for the RCE GaAsSb avalanche photodiode (APD) with separate absorption, charge, and multiplication regions (SACM). At 90% of the breakdown, the dark current of the SACM APD was 5 nA. The GaAsSb SACM APD also exhibited very low multiplication noise and k/sub eff/ was approximately 0.1, which is the lowest ever reported for APDs operating at 1.3 /spl mu/m.     

An efficient improvement of the AESOPS algorithm for power systemeigenvalue calculation

This paper describes a simple but efficient modification to improve the well known PEALS/AESOPS algorithm for power system eigenvalue calculation. The modified algorithm is a Newton-Raphson iteration scheme which converges significantly faster than AESOPS. The algorithm is linked to the operational transfer matrix equation method. An efficient operational matrix based formula is suggested to calculate the sensitivity of an electromechanical eigenvalue with respect to the transfer function of a power system stabilizer. Results for a 21 generator power system are described     

Long-term expression and secretion of human glucocerebrosidase by primary murine and human myoblasts and differentiated myotubes

The majority of studies dealing with DNA analyses are made on fixed cells. In this context, the efficiency as fixatives of ethanol, methanol, acetone, Carnoy, Boehm-Sprenger and aldehydes was determined using two different DNA fluorescent probes, Hoechst 33342 and propidium iodide. The purpose of our study was to find the fixative that would provide the best results with respect to the following parameters: aggregates, cell size and granularity, and DNA staining analysis. Using murine fibroblasts, we found that 68% ethanol, 85% methanol and aldehydes did not increase aggregate formation, whereas Carnoy, acetone or Boehm-Sprenger fixatives did. The results show that aldehydes seem to alter cell size least. All fixatives induce an increase in cell granularity, which is very pronounced with alcohols, but aldehydes alter morphology less than alcohols. We observed that the fixatives giving the best resolution with Hoechst 33342 staining lead to a lower measurement variability than with propidium iodide staining. This study leads us to conclude that 68% ethanol and 85% methanol can be considered as appropriate fixatives for flow cytometry studies of DNA content.     

Lock-granularity analysis tools in SVR4/MP

The design of the SVR4/MP multiprocessing system with fine-grained locking is discussed. SVR4/MP scales efficiently to eight processors under a database transaction processing workload and typical multiuser benchmarks. In developing SVR4/MP, initial lock placement was deemphasized and rapid, iterative tuning of lock placement was the focus. Sophisticated tools were used to perform iterative overall performance and scalability tuning of the operating system. The tools developed to determine lock granularity quantitatively are described and an example of their use to optimize overall system efficiency is presented     

Giant ureteral stone in a 4-year-old boy

A 4-year-old boy presented with sudden onset of fever, pyuria, and bacteriuria. Ultrasound revealed left hydronephrosis and hydroureter. A plain abdominal radiography and excretory urogram showed a giant ureteral stone measuring 9 cm causing ureteral obstruction. Underlying anatomic or metabolic abnormalities were not detected. Extraction of the stone resulted in complete disappearance of the hydronephrosis and hydroureter.