Lightweight Concrete Using Local Industrial By-product

Construction is one of the largest users of energy, material resources and water and it is a formidable polluter. One of the major materials used in construction is concrete and ordinary concrete contains about 12% cement which is a major producer of greenhouse gas in the world. The use of waste materials as partial replacement of cement in concrete reduces greenhouse gases, frees up land fill space, and reduces raw materials consumption. This contributes towards sustainable development, as in a sustainable society, nature is not subject to systematically increasing concentrations of substances extracted from the earth＇s crust. This research work explores the possibility of replacing some percentage of cement in concrete with marble sludge powder to produce lightweight concrete. This was achieved by determining the compressive strength and some hardened properties of concrete like sorptivity and carbonation with marble sludge. The results so far have been able to prove that lightweight concrete can be produced when some percentage of cement is replaced with this waste.     

Reducing the disruptive effects of interruption: A cognitive framework for analysing the costs and benefits of intervention strategies

Interruptions are ubiquitous, and they can lead to disastrous consequences. The goal of this paper is to describe remedies that have been proposed to reduce the disruption caused by interruptions based on an understanding of how principles of human cognitive processing bear on the sequence of events that take place during an interruption. We show that interruptions tap disparate cognitive operations, from attention to decision making to memory. We illustrate how these cognitive processes can lead to interruption-induced errors, and how they can help in understanding potential problems with remedies that have been proposed to ameliorate those effects. We present a framework in which the load imposed by the task and the cost of an error suggests the types of solutions that should be considered for a given domain. We then discuss the implications of this approach for understanding and reducing the negative effect of interruptions in transportation domains.     

Observations in the statistical analysis of NBG-18 nuclear graphite strength tests

The purpose of this paper is to report on the selection of a statistical distribution chosen to represent the experimental material strength of NBG-18 nuclear graphite. Three large sets of samples were tested during the material characterisation of the Pebble Bed Modular Reactor and Core Structure Ceramics materials. These sets of samples are tensile strength, flexural strength and compressive strength (CS) measurements. A relevant statistical fit is determined and the goodness of fit is also evaluated for each data set. The data sets are also normalised for ease of comparison, and combined into one representative data set. The validity of this approach is demonstrated. A second failure mode distribution is found on the CS test data. Identifying this failure mode supports the similar observations made in the past. The success of fitting the Weibull distribution through the normalised data sets allows us to improve the basis for the estimates of the variability. This could also imply that the variability on the graphite strength for the different strength measures is based on the same flaw distribution and thus a property of the material.     

Main, mediating, and moderating effects of social support on the well-being of survivors of intimate partner violence across 2 years.

Intimate partner violence is a serious and pervasive social problem with deleterious consequences for survivors’ well-being. The current study involved interviewing 160 survivors 6 times over 2 years to examine the role of social support in explaining or buffering these negative psychological consequences. The authors examined both between- and within-persons variability to explore women’s trajectories regarding their experiences of abuse, social support, depression, and quality of life (QOL). Findings revealed the complex role of social support on women’s well-being. Evidence was found for main, mediating, and moderating effects of social support on women’s well-being. First, social support was positively related to QOL and negatively related to depression. Social support also partially explained the effect of baseline level and subsequent change in physical abuse on QOL and depression over time, partially mediated the effects of change in psychological abuse, and moderated the impact of abuse on QOL. The buffering effects of social support were strongest at lower levels of abuse. Implications for future research and intervention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of UV irradiation on organic matter extracted from treated Ohio River water studied through the use of electrospray mass spectrometry

Ohio River water was treated by settling, sand filtration, and granular activated carbon filtration. It was then irradiated by low-pressure (monochromatic) and medium-pressure (polychromatic) UV lamps to investigate the effects of UV irradiation on the extracted organic matter (EOM). When the EOM, collected by solid phase extraction cartridges, was analyzed by conventional UV spectroscopy and size exclusion chromatography (SEC), no significant changes in the EOM were revealed for various UV doses. Positive and negative electrospray ionization mass spectrometry (ESI-MS) of the EOM produced mass spectra that vary significantly with UV dose. The UV dosage conditions also appear to affect the reactivity of the EOM to subsequent chlorination. The magnitude of the spectral changes is generally greater for medium-pressure lamps than for low pressure and increases with UV exposure. Based on the observed MS peaks, the changes may be due to the presence of lignin, resulting perhaps from photooxidation and/or photo rearrangement of macromolecules in the sample. When chlorination is used for secondary disinfection, these results suggest that it may be important to consider the effects of UV irradiation on the organic matter in the water before applying UV disinfection technology to a particular source water.     

Isotopic identification of the sources of lead contamination for white storks (Ciconia ciconia) in a marshland ecosystem (Doñana,S.W. Spain)

White storks (Ciconia ciconia) fed in contaminated waters resulting from the Aznacollar acid mining-sludge spillage into the R. Guadiamar, which feeds the eastern flank of the Guadalquivir marshes (Do?ana), S.W. Spain. The sludge was rich in a range of toxic elements, and in organic pollutants such as the aromatic amines. Storks did not exhibit elevated metals in their blood immediately following the accident, but chick blood collected the year following the accident showed genotoxic damage compared to the controls. In this study lead isotope analysis was used to assess if the storks had ingested sludge-derived contaminants. The sludge lead isotope ratio was distinct from that of the Do?ana sediments. The stork blood lead isotope ratios exactly matched that of the sludge. It was concluded that the storks had ingested sludge-derived contaminants. A detailed study of the lead contamination along the R. Guadiamar and the R. Guadalquivir (of which the Guadiamar is a tributary) was also conducted to place the white stork colony lead exposure in the context of the spatial contamination of the storks' habitat.     

NMDA receptor antagonism impairs reversal learning in developing rats.

Four experiments examined the effect of dizocilpine maleate (MK-801), a noncompetitive N-methyl-Daspartate (NMDA) receptor antagonist, on reversal learning during development. On postnatal days (PND) 21, 26, or 30, rats were trained on spatial discrimination and reversal in a T-maze. When MK-801 was administered (intraperitoneally) before both acquisition and reversal, 0.18 mg/kg generally impaired performance, whereas doses of 0.06 mg/kg and 0.10 mg/kg, but not 0.03 mg/kg, selectively impaired reversal learning (Experiments 1 and 3). The selective effect on reversal was not a result of sensitization to the second dose of MK-801 (Experiment 2) and was observed when the drug was administered only during reversal in an experiment addressing state-dependent learning (Experiment 4). Spatial reversal learning is more sensitive to NMDA-receptor antagonism than is acquisition. No age differences in sensitivity to MK-801 were found between PND 21 and 30. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of Work-of-sintering concepts in powder metals

One of the current challenges facing the particulate materials industry is developing simple, accurate models to predict sintered properties. Work-of-sintering concepts, where time-temperature integrals are used in such models, offer a solution to this problem. In this study, the master sintering curve concept is applied to several powder metal systems: 17 to 4PH stainless steel, 316L stainless steel, nickel, niobium, tungsten heavy alloys with two different compositions, and molybdenum. A detailed explanation of the construction of these curves is given, including methods used to calculate the apparent activation energy for sintering and to curve-fit experimental data to a sigmoid function describing the master sintering curve. Discussion of the results shows that the master sintering curve can be applied to powder metal systems, even those that use liquid phase during sintering.     

On deceiving ourselves about deception: Reply to Rubin.

Replies to the comments of Z. Rubin (see record 1985-16257-001) on the present authors' study (see record 1984-00117-001) of the role of debriefing in ameliorating harmful effects of deception or other potentially harmful manipulations in psychology experiments. It is suggested that Rubin misunderstood the purpose of the study, which was to focus on Ss' global perceptions of their cumulative research experiences rather than the specific effects of particular kinds of experimental manipulations. (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)