The compressive strength of cement blocks permeated with an organic phase change material

The authors investigate the feasibility of constructing walls and partitions with enhanced heat storage capability from cement blocks permeated with an organic phase change material (pressed stearic acid). The blocks are lightweight, easy to produce and are cured in the same way as cement or concrete.The ratio of components (cement, stearic acid (SA) and water) was optimized with respect to compressive strength. With normal portland cement, the best compressive strength 2.2 MPa was obtained with a ratio C:SA:W of 1:0.8:0.65 (i.e. 32% stearic acid) after 28 days of curing. This was increased to 4.4 MPa when high early strength cement was used, about as strong as Sipporex, lightweight concrete or lightweight clay bricks.As expected, the compressive strength decreased linearly with temperature between 25°C and 100°C, at a rate of 15 kPa/°C. The drying shrinkage of the modules was found to be 50% greater than for cement mortars. The addition of fibreglass gave only a 15% increase in the compressive strength. Samples containing 35% fatty acid showed surface deterioration after 200 thermal cycles (between ?5°C and 6 °C) while none was observed with those containing 32%. The dynamic modulus of elasticity did not change after 200 cycles.     

Liquid-crystal light valves

Liquid-crystal light valves have been built in which a relatively weak-signal image controls the flow of light to a much brighter projected image. The brightness of the projection light is limited only by heating in the light valve, and so great optical gain is possible. Brightness gains of 10?20 have been achieved with 30?W/cm2 of signal light at an efficiency of 15%. Resolutions of 5 line pairs per mm on the light valve and contrast ratios of 10:1 have been obtained, with a response time of about 0.1 s. With improvements, resolutions of 10?20 line pairs per mm relatively fast response and sensitivity to signal-light levels of nW/cm2 may be expected.     

Short-pulse multiline and multiband energy extraction in high-pressure CO2-laser amplifiers

The ability of a nanosecond or shorter CO2-laser pulse consisting of a single vibrational-rotational transition to extract energy from an atmospheric-pressure CO2amplifier is limited owing to the finite rotational thermalization time in CO2and the larger number of rotational states which share the stored energy. Theoretical studies are reported which indicate that utilizing an incident pulse consisting of several vibrational-rotational lines within the 10.6-μ band substantial improvements can be obtained over single-line extraction. Even more dramatic improvements are possible if the pulse contains vibrational-rotational transitions at both the 10.6- and 9.6-μ bands. Quantitative energy-extraction results are presented for an input Gaussian pulse consisting of1-5 10.6-mutransitions, and for a pulse containing one line at 9.6 μ and one at 10.6 μ, traversing a 1-m amplifier, for a wide range of input energies, pulsewidths, and gas pressures. Possibilities of using multiband techniques for pulse shaping are also discussed.     

Children's generosity as influenced by deservedness of reward and type of recipient.

24 5-6 yr-olds and 24 8-9 yr-olds were given the opportunity to donate money to a charity under conditions varying the characteristics of the recipient (crippled child vs crippled adult) and the situation in which the child acquired the resource for generosity (earned vs windfall). On the basis of previous literature, it was expected that these conditions would affect the age differences often reported in generosity. Contrary to such expectations, there was more generosity toward crippled children than crippled adults across both age groups. There was an increase in generosity with age across conditions, with girls consistently donating more than boys. Methodological issues and reactions to stigmatized others are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Channel microband electrode arrays for mechanistic electrochemistry. Two-dimensional voltammetry: transport-limited currents

A channel electrode array, with electrodes ranging in size from the millimeter to the submicrometer scale, is used for the amperometric interrogation of mechanistically complex electrode processes. In this way, the transport-limited current, measured as a function of both electrode size and electrolyte flow rate (convection), is shown to provide a highly sensitive probe of mechanism and kinetics. The application of "two-dimensional voltammetry" to diverse electrode processes, including E, ECE, ECEE, EC', and DISP2 reactions, is reported.     

On the psychometric principles of affect.

D. Watson and L. A. Clark (see record 1997-03581-003) announced "two fundamental psychometric principles" (p. 282) of affect: The positive correlation between affects with the same valence tends to be substantial, whereas the negative correlation between affects with opposite valence tends to be weak. These allegedly robust empirical generalizations underlie various conceptual models of affect (such as those that posit an independence between positive and negative affect) and various scales of affect. The authors offer an alternative analysis: The correlation between two affects is a function of the angle between them within a circular ordering. Two data sets were reanalyzed and showed predicted exceptions to Watson and Clark's principles: same-valenced pairs with weak correlations and oppositely valenced pairs with substantial correlations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)