Mechanical Properties of Partially Dense Alumina Produced from Powder Compacts

The elastic modulus ( E ), the critical strain energy release rate ( G _c), and the flexural strength (σ) have been determined for two partially dense alumina bodies produced from the same powder but with different initial densities. The mechanical properties were measured for specimens fabricated at four different relative densities. The measured elastic modulus, critical strain energy release rate, and a calculated critical stress intensity factor ( K _c) were observed to be linearly related to (ρ–ρ₀)/(1 –ρ₀), where ρ is the current relative density and ρ₀ is the initial relative density of the powder compact. With the observed linear relations for E, G _c (or K _c), and the assumption that the crack length responsible for failure was present in the initial powder compact and shrunk in proportion to the relative density change, a Griffith equation was constructed to estimate the strength at any relative density. This relation was in good agreement with measurements.     

What’s the Big Deal About Big Data Loss (Actually Theft)?

I get confused about the way security deals with so-called data loss (actually theft). Recently we had what the media called, in various forms, a crisis, a huge cyberattack against, and so forth against JPMorgan Chase (JP), one of many such instances in the last year. So I looked at the various claims surrounding this instance, and found consistently that the only known “loss” of data was names, addresses, phone numbers, and e-mail addresses. And it was not lost! It was stolen, and JP still has copies. So, to be really clear, this is more or less the same information found in the phone book, available from various mailing list providers for less than a tenth of a penny a piece, and of no significant consequence I can identify. The cost of “protection” for consumers is $90 per person per year, although I do not quite get what this cost covers.     

Axial Compression of Footings in Cohesionless Soils. II: Bearing Capacity

An extensive database of full-scale field load tests was used to examine the bearing capacity for footings in cohesionless soils. Each load test curve was evaluated consistently to determine the interpreted failure load (i.e., bearing capacity) using the L1-L2 method. This test value then was compared with the theoretical bearing capacity, computed primarily using the basic Vesi? model. The comparisons show that, for footing widths B>1?m, the field results agree very well with the Vesi? predictions. However, for B<1?m, the results indicated a relationship between B and the predicted-to-measured bearing capacity ratio. Accordingly, a simple modification was made to the bearing capacity equation, and the resulting predictions are very good.     

The goal specificity effect on strategy use and instructional efficiency during computer-based scientific discovery learning

Using a computer-based scientific discovery learning environment on buoyancy in fluids we investigated the effects of goal specificity (nonspecific goals vs. specific goals) for two goal types (problem solving goals vs. learning goals) on strategy use and instructional efficiency. Our empirical findings close an important research gap, because in earlier studies the goal specificity effect either was restricted to one goal type or goal type was confounded with goal specificity. In addition, there is hardly a study with empirical evidence for the goal specificity effect on strategy use, which counts even more for a cognitive cost-benefit ratio as a dependent variable. Instead, in earlier studies the goal specificity effect has been attributed to differences in strategy use and cognitive cost-benefit ratio in a rather theoretical way. In the present study for strategy use an interaction was found between goal specificity and goal type, indicating that the goal specificity effect occurs only in case of problem solving goals, but not in case of learning goals. Compared to students provided with specific problem solving goals, students who worked on nonspecific problem solving goals, used a control of variables-strategy more frequently. Additionally, we found a main effect of goal specificity on instructional efficiency for both of the goal types, pointing at a more favorable relationship between performance gain and cognitive load caused by nonspecific goals.     

Physiological compliance and team performance

Physiological compliance (PC) refers to the correlation between physiological measures of team members over time. The goals of this study were to examine ways of measuring PC in heart rate variability (HRV) data and the relationship between PC and team performance. Teams were tasked with entering both real and simulated rooms and “shooting” individuals with a weapon and identifying individuals without a weapon. The linear correlation and directional agreement PC methods were shown to be the most sensitive to differences in performance, with greater PC being associated with better performance. The correlation method when applied to a measure of respiratory sinus arrhythmia (RSA) revealed a significant difference between high and low performers (t[8] = −2.31, p = 0.03) and the directional agreement applied to inter-beat-intervals and RSA revealed trend-level differences (t[4.62] = −1.86, p = 0.06 and t[8] = −1.68, p = 0.07). These results suggest that PC may have merit for predicting team performance.     

Improved creaminess of low-fat yoghurt: The impact of amylomaltase-treated starch domains

Amylomaltase-treated starch (ATS) is an excellent creaminess enhancer in yoghurt. Small amounts of ATS raised the creaminess perception of low-fat yoghurt (1.5%) to that of full-fat yoghurt (5%). In this way, a reduction in fat-related energy value could be achieved from 45 to 21.5 kcal/100 g product. The functionality of ATS in set yoghurt resulted from discrete domains of ATS that resemble the microstructural behaviour of fat particles. The microstructure of the yoghurt is dominated by the protein and the ATS domains are enclosed in or bound to this protein network. The perceived creaminess resulted from in-mouth melting of these ATS domains due to a combined effect of their physical melting and hydrolysis by amylase present in the saliva.     

Learning by generating vs. receiving instructional explanations: Two approaches to enhance attention cueing in animations

This study investigated whether learners construct more accurate mental representations from animations when instructional explanations are provided via narration than when learners attempt to infer functional relations from the animation through self-explaining. Also effects of attention guidance by means of cueing are investigated. Psychology students were given retention, inference, and transfer tests after studying a cued or an uncued animation of the cardiovascular system with learner-generated self-explanations or with externally provided instructional explanations. Results indicated that cued animations were more effective than uncued animations. Furthermore, results on retention and transfer indicated no differences between self-explaining and providing instructional explanations, but instructional explanations accompanying animations led to higher inference scores. It is concluded that whether explanations are generated or presented may be less important than the provision of cues that enable focused processing of presented or produced explanations.