Triggering steam explosions of single drops of a molten ferrosilicon alloy with a simple encapsulated mechanical impactor

We have developed a simple and inexpensive encapsulated mechanical impactor that can be operated under water. The unit reproducibly generates upward-directed pressure transients in the water with peaks of approximately 0.13 MPa measured 100 mm above its surface. These pulses have been used to trigger steam explosions of drops of a molten ferrosilicon alloy when they are either just above the unit in free fall through the water or shortly after they land on its surface. The impactor is study, reliable, safe, and environmentally neutral and resets for reuse within seconds. Compared to other triggering techniques, the impactor does not generate light, bubbles, or strong water motion that obscure or appreciably affect the initiation or early stages of the steam explosions. This permits good imaging and measurements at essentially all times during the triggering and subsequent development of the explosions.     

The Management of Knowledge during Design and Implementation of Process Technologies

Knowledge and learning play a major part in the successful implementation of process technologies. We suggest that managers of implementation projects can improve the initial performance levels of the process in which a new technology resides by ensuring that useful knowledge, present in the organization at the start of the implementation project, is employed to greatest effect during the design of the modified process and that new learning is not lost. This does not necessarily require major investment in computerized systems – merely exploring what potentially useful knowledge is already available within the organization, or can readily be obtained from external contact, may improve the efficiency of technology implementation. Use of available knowledge can also help to speed up the implementation process by reducing the number of, and time required for, the adaptations necessary to get the process to the desired performance level.     

Forecasting reliability growth

This paper describes a method for estimating and forecasting reliability from attribute data, using the binomial model, when reliability requirements are very high and test data are limited. Integer data—specifically, numbers of failures — are converted into non-integer data. The rationale is that when engineering corrective action for a failure is implemented, the probability of recurrence of that failure is reduced; therefore, such failures should not be carried as full failures in subsequent reliability estimates. The reduced failure value for each failure mode is the upper limit on the probability of failure based on the number of successes after engineering corrective action has been implemented. Each failure value is less than one and diminishes as test programme successes continue. These numbers replace the integral numbers (of failures) in the binomial estimate. This method of reliability estimation was applied to attribute data from the life history of a previously tested system, and a reliability growth equation was fitted. It was then ‘calibrated’ for a current similar system's ultimate reliability requirements to provide a model for reliability growth over its entire life-cycle. By comparing current estimates of reliability with the expected value computed from the model, the forecast was obtained by extrapolation.     

A conceptual framework for examining adolescent identity, media influence, and social development.

The adolescent identity, media, and sociocognitive schema (AIMSS) framework offers a theoretical understanding of adolescent consumption and cognitive processing of media entertainment. Review and integration of mass communication theory, developmental theory, and ecological theory serves as the conceptual foundation. The framework outlines linkages between media exposure and adolescent development, in particular adolescent identity formation and social competence. A key contribution of the model is consideration of the positive and negative aspects of adolescent cognition and behavioral functioning. The present article offers several recommendations for testing the utility of the AIMSS framework. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using computer animated graphics with science instruction with children.

The effects of animated presentations and practice were studied in a computer-based science lesson involving fourth- and fifth-grade students. Three levels of visual elaboration (static graphics, animated graphics, and no graphics) were crossed with three levels of practice (behavioral, cognitive, and no practice). Behavioral practice consisted of traditional questioning and cognitive practice consisted of a structural simulation. Animated graphics were superior to static graphics and no graphics so long as practice was provided. Behavioral practice was effective only when paired with lessons containing animated graphics. Cognitive practice was generally superior to the other practice conditions and did not appear dependent on visual elaboration. These results suggest that animated presentations can promote learning under certain conditions, and they also demonstrate a successful application of interactive graphics in the design of cognitively based practice activities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studies on non-enzymic browning in orange juice using a model system based on freshly squeezed orange juice

An orange juice based model system was set up wherein variables such as the addition of glucose, lysine, sorbitol and L -ascorbic acid and changes in pH and storage temperature were introduced to study their effects on L -ascorbic acid degradation and on browning. The addition of glucose, lysine and sorbitol did not have a significant effect on L -ascorbic acid degradation, whereas added L -ascorbic acid acted solely as a reserve material. In terms of browning, a change in pH and storage at elevated temperature produced a synergistic effect in the development of brown colour which was enhanced by the introduction of additives. Based on the results obtained, L -ascorbic acid appears to be the precursor in the non-enzymic browning occurring in this type of sample due to the formation of reactive carbonyl compounds produced upon its degradation which tend to polymerise, or to react with nitrogenous compounds, to give brown pigments.     

Holographic polymer dispersed liquid crystals (HPDLCs) containing triallyl isocyanurate monomer

The morphology and corresponding performance of holographic polymer dispersed liquid crystals (HPDLCs) based on thiol-ene polymer are dependent on a number of factors including the gel point conversion of the polymer, polymerization kinetics, and extent of liquid crystal (LC) phase separation. Previous research of HPDLC reflection gratings made from thiol-allyl ether polymer indicates that increasing polymerization rate in systems with moderate gel point conversion can improve diffraction efficiency (DE). This work examines HPDLC reflection gratings that contain the ene monomer triallyl isocyanurate (TATATO). In HPDLCs, thiol-TATATO polymerization is two times faster than the thiol-ene polymerization of triallyl ether. By substituting TATATO for triallyl ether, the LC droplet size within HPDLC reflection gratings decreases from 100 nm to 25 nm. The dramatic reduction in LC droplet size for thiol-TATATO HPDLCs increases baseline transmission from 55% in thiol-triallyl ether HPDLCs to 90% at 450 nm. Unfortunately, the DE of thiol-TATATO HPDLCs is only approximately 10% due to poorly defined lamellae in the grating morphology. As determined with real-time IR (RTIR) spectroscopy, thiol-TATATO HPDLCs have significantly faster LC demixing kinetics in comparison to thiol-allyl ether HPDLCs. During holographic photopolymerization, the increased rate of LC demixing causes formation of LC droplets throughout the grating. The low DE of thiol-TATATO HPDLCs can be improved by mixing TATATO and allyl ether monomer. The morphology of ternary thiol-ene HPDLC formulations containing TATATO and allyl ether has a well-defined grating structure due to increased LC solubility in the system, an average LC droplet size of 50 nm, and baseline transmission of nearly 85% at 450 nm.     

Culturally sensitive psychotherapy for Puerto Rican children and adolescents: A program of treatment outcome research.

Recognition of cultural distance between Hispanic clients and non-Hispanic therapists has prompted efforts to introduce culture into therapy, but there is little evidence that such efforts influence treatment outcomes. This article evaluates treatment outcomes from a program of research on modeling therapy with Puerto Ricans, targeting anxiety symptoms, acting-out behavior, and self-concept problems. Evaluation of outcomes confirmed the impact of culturally sensitive modeling therapy on anxiety symptoms and other selected target behaviors, but negative treatment effects also were evident. Results suggest that new approaches to psychotherapy for special populations, such as Hispanic children and adolescents, should be buttressed by programmatic research oriented toward the comparative evaluation of treatment outcomes and should be attuned to therapeutic processes mediating between culture and outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)