The association between parent–child conflict and adolescent conduct problems over time: Results from a longitudinal adoption study.

A handful of prior adoption studies have confirmed that the cross-sectional relationship between child conduct problems and parent–child conflict at least partially originates in the shared environment. However, as the direction of causation between parenting and delinquency remains unclear, this relationship could be better explained by the adolescent's propensity to elicit conflictive parenting, a phenomenon referred to as an evocative gene–environment correlation. In the current study, the authors thus examined the prospective relationship between conduct problems and parent–child conflict in a sample of adoptive families. Participants included 672 adolescents in 405 adoptive families assessed at 2 time points roughly 4 years apart. Results indicated that parent–child conflict predicts the development of conduct problems, whereas conduct problems do not predict increases in parent–child conflict. Such findings suggest that evocative gene–environment correlations are highly unlikely to be an explanation of prior shared environmental effects during adolescence. Moreover, because the adolescents in this study do not share genes with their adoptive parents, the association between conduct problems and parent–child conflict is indicative of shared environmental mediation in particular. Implications of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and characterization of core–shell SiO2@(Er3+,Yb3+):Lu2O3

We synthesized crystalline Erbium Er³⁺ and Ytterbium Yb³⁺ codoped -Lu₂O₃ nanolayers on SiO₂ microspheres using the modified Pechini method. Two different kinds of precursors, nitrates and chlorides, have been used leading to a layer-to-layer morphology and necklaces structures, respectively. In both cases, the size of nanocrystallites constituting the optical active layer is around 5 nm. We performed X-ray powder diffraction to confirm the cubic crystalline structure of the sesquioxides layer. High resolution transmission electron microscopy analyses corroborate the crystalline nature of the layer. The optical emission of Er³⁺ in the visible range has been recorded.     

Predicting the contractual cost of unplanned shutdowns of power stations: An accelerator-driven subcritical reactor case study

This paper discusses analysis of the acute contractual cost of a failure to supply electricity from the perspective of power station owners. It presents a model for analysing the financial cost to an electricity supplier in the context of a national grid when a power station unexpectedly instantaneously shuts down. The model probabilistically samples historical market data and includes analysis of the impact on the system buy price of historic unplanned generator shutdowns. A case study is presented for a potential future nuclear power station concept, the Accelerator-Driven Subcritical Reactor (ADSR), in the UK market. The reliability of ADSRs is a key issue in their future development. The model is used to identify an upper limit on the amount an operator should be willing to pay for reliability improvements that mitigate unplanned shutdowns. The case study results are presented in a form that allows the reader to scale the cost of accelerator system failures for any capacity factor and coefficient of reliability, for a range of discount rates.     

Modeling Manganese Oxidation with KMnO4 for Drinking Water Treatment

Manganese (Mn) in a drinking water distribution system can cause multiple aesthetic problems including discolored water and fouling or scaling of fixtures. Oxidation and solid-liquid separation processes are typically employed at a treatment plant to limit the concentration of Mn entering the distribution system. Potassium permanganate (KMnO4) is commonly used to oxidize the manganous ion (Mn+2) to manganese oxide (MnO2). In this study, a mechanistic model is applied to the oxidation of manganese at a treatment plant. Literature kinetic constants (determined with artificial water) are compared with the values obtained for the plant's natural water. The solution and surface phase oxidation rate constants determined with the natural water are two to six orders of magnitude less than those determined with the artificial water. The reduced oxidation rate in the natural water is attributed to the presence of dissolved organic matter, which can exert a competitive demand on the oxidant and interfere with the oxidation by complexing Mn+2. The development of an additional rate constant for the oxidation of dissolved organic matter improves the modeling results for KMnO4 concentration versus time, but only marginally explains the Mn+2 oxidation rate differences.     

New Technology for Preventing Residential Electrical Fires: Arc-Fault Circuit Interrupters (AFCIs)

A new generation of residential electrical branch circuit breakers that incorporates technology to detect and mitigate the effects of arcing faults is described. Fire loss estimates attributed to electrical wiring and the development of the arc-fault circuit interrupter for the prevention of residential electrical fires are discussed. The industry voluntary standard for arc-fault circuit interrupters as well as the 1999 National Electrical Code requirement are reviewed.     

An experimental evaluation of a residential-sized evaporatively cooled condenser

In this paper, the performance of an innovative evaporatively cooled condenser is compared with that of a conventional air-cooled condenser for a split heat pump system. The system was tested in an environmentally controlled test chamber that was able to simulate test conditions as specified by ASHRAE Standard 116. Tests to optimize refrigerant charge and short tube restrictor size were conducted using refrigerant HCFC-22. The wheel rotation speed of the evaporative condenser was also optimized experimentally to maximize the coefficient of performance. Using these optimum parameters, steady state and cyclic performance tests were conducted. The experimental results showed that the evaporative condenser has a higher capacity than the air-cooled condenser by 1.8 to 8.1%, a higher COP by 11.1 to 21.6%, and a higher SEER by 14.5%.     

Surface grain structure evolution in hot rolling of 6061 aluminum alloy

During hot deformation of Al–Mg–Si alloys, a non-uniform microstructure is developed due to differences in localized strain. Physical simulations were performed to examine the effects of processing parameters such as deformation temperature, total reduction, rolling schedule and alloying additions on the grain structure evolution. Overall, the kinetics of recrystallization followed the traditional trends predicted by JMAK kinetics. Electron backscatter diffraction (EBSD) was used to quantify the difference in recrystallization kinetics at the sample surface and mid-thickness. The results showed that the surface showed elevated kinetics when compared to the sample mid-thickness.     

Finite element modeling of polymer hot embossing using a glass‐rubber finite strain constitutive model

A hyperelastic–viscoplastic constitutive model for amorphous polymers was used in finite element simulations of micro‐hot embossing across the glass transition. The model was selected for its ability to capture finite strain temperature and rate dependence over a wide range of temperatures, including across the glass transition. The simulations focused on the glass transition temperature regime, and particularly probed the effects of time and temperature during cooling and mold release. The results show that strong temperature sensitivity of the material across the glass transition leads to a wide range of required embossing force and springback. The interplay between changes in material properties upon cooling and stress relaxation can lead to significant increases in embossing force during the cooling stage, especially when high cooling rates are employed. The effects of thermal expansion also complicate the problem during rapid cooling. Nonlinear material behavior is shown to affect results in parametric hot embossing studies. Careful tailoring of embossing temperature, cooling rate, and demolding temperature is critical in acceptable feature replication. The best results are found for moderate cooling rates, which allow adequate time for stress relaxation in the material prior to mold release. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Theoretical studies on VPI-5. 3. The MS-Q force field for aluminophosphate zeolites

Aluminophosphate zeolite is an artificial material which shows strange hydrophilicity. We have been investigating the reason by quantum mechanics, and found that the hydrophilicity of this zeolite depended on the local geometric deformation, and speculated that the site-specific hydrophilicity might be explained by differences in the stiffness of the local deformation determined by the location with the pore structure. In order to test these ideas, we construct a reliable force field based on the new MS-Q approach developed by Demiralp, Cagin, and Goddard. Our force field well reproduces the experimental structure of VPI-5.     

Visualizing "green oil" in live algal cells

We report here that BODIPY 505/515, a green lipophilic fluorescent dye, serves as an excellent vital stain for the oil-containing lipid bodies of live algal cells. BODIPY 505/515 vital staining can be used in combination with fluorescent activated cell sorting to detect and isolate algal cells possessing high lipid content.