Global perspectives and options for long-range energy strategies

An attempt is made to envisage the evolution of energy supply and demand for the next 50 yr. Seven identified world regions are considered in order to bring out their interrelationships and to provide a background against which national or regional energy strategies can be evaluated. The principal tool for doing this is the elaboration of two detailed and largely internally consistent scenarios. This permits us to make interpolations and extrapolations. The scenarios are only conceptualizations, not predictions. This paper addresses only the technical and substantive aspects of the energy problem and does not look into political, institutional, and societal problems. It is thus meant to serve as a basis for broader policy decision-making.     

The constant stress term

The importance of retaining the second, constant stress term of the series expansion for local stress is demonstrated both analytically and numerically. It is shown how the standard singular expressions for the stress and displacement field in the vicinity of the crack tip need to be corrected. A load applied parallel to the crack shows up solely and entirely in this constant term. Omitting this term not only denies the physical presence of such a load and hence violates the principle of the uniqueness of the solution of boundary value problems of linear elasticity, but also misleads one into thinking that load biaxiality does not influence fracture behavior. It is shown analytically and numerically that the standard expressions are correct only for equal tension-tension loading. The numerical results show that K_I is independent of a horizontal load only when the constant stress term is included.     

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Journal of the American Oil Chemists' Society -     

Liming impacts barley yield over a wide concentration range of soil exchangeable cations

Liming has widespread and significant impacts on soil processes and crop responses. The aim of this study was to describe the relationships between exchangeable cation concentrations in soil and the relative yield of spring barley. The hypothesis was that yield is restricted by the concentration of a single exchangeable cation in the soil. For simplicity, we focused on spring barley which was grown in nine years of a long-term experiment at two sites (Rothamsted and Woburn). Four liming rates were applied and in each year the relative yield (RY) and the concentrations of exchangeable cations were assessed. Liming had highly significant effects on the concentrations of most exchangeable cations, except for Cu and K. There were significant negative relationships (either linear or exponential) between the exchangeable concentrations of Mn, Cd, Cr, Al, Fe, Cu, Co, Zn and Ni in soil and soil pH. The relationships between RY and the concentrations of selected exchangeable cations (Mn, Ca and Al) were described well using log-logistic relationships. For these cations a significant site effect was probably due to fundamental differences in soil properties. At both sites the concentrations of exchangeable soil Al were excessive (>?7.5 mg kg^?1) and were most likely responsible for reduced barley yields (where RY?≤?0.5) with soil acidification. At Rothamsted barley yield was non-limited (where RY?≥?1) at soil exchangeable Mn concentrations (up to 417 mg kg^?1) greater than previously considered toxic, which requires further evaluation of critical Mn concentrations.

     

Demographic, individual, and family relationship correlates of serious and repeated crime among adolescents and their siblings.

Collected demographic, psychometric (the Behavior Problem Checklist, the Vocabulary subtest of the WAIS or WISC—R, the Eysenck Personality Inventory, a family relationship questionnaire, and an unrevealed differences questionnaire), and observational measures on 163 families with an adolescent son to determine their relationship to adolescent criminal activity. In 74 families the father was present, but in 89 families he was absent. Stepwise multiple regression analyses showed that socialized-aggressive disorder, as rated by the parent(s), was the most consistent and powerful predictor of serious and repeated arrests among the male adolescents and their siblings. The adolescent's age at first arrest was the second most powerful predictor. It is suggested that determination of high risk indicates that the individual, family, peer, and social factors involved must be assessed to determine what interventions are required. (51 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combination of finite element analysis and analytical crack tip solution for mixed mode fracture

A finite element program was developed which combines the analytical crack tip solution with a conventional finite element analysis and evaluates various crack tip parameters as part of the solution. This program was used to analyze cracked specimens subjected to mixed mode loading. The importance of retaining the second term of the series expansion for local stress, a contribution which is independent of the distance from the crack tip, was demonstrated. It was first shown analytically that the presence of a load applied parallel to the crack reveals itself only through this constant second term, which vanishes only for specific loading conditions. The results of the numerical analysis demonstrate that the stress intensity factor K_I is independent of the load applied parallel to the crack only when this term is included in the analytical crack tip solutions. Failure to include the constant term has the effect that K_I varies with the horizontal load. The parameter K₁₁ is independent of this load in both cases. This indicatesonce again that it is this constant term which accounts solely and entirely for the presence of a load applied parallel to the crack.     

Block copolymer vesicles—using concepts from polymer chemistry to mimic biomembranes

Owing to the increasing interest in self-assembled structures from block copolymer materials, we present here a review of recent literature concerning amphiphilic block copolymer vesicles. A vesicular morphology is applicable not only in such fields like delivery-release and biomineralization, but also has been utilized for preparation of nanoreactors and incorporation of biological macromolecules.The organization of this paper is the following: we first provide the readers with the overview of the current literature concerning the vesicle preparation and most commonly used experimental methods applied for vesicle investigations. Next, we consider the vesicle formation in more detail and present the morphologies resulting from the interplay of factors influencing vesicular structures in solution. Further, membrane properties will be reviewed, and finally, we wish to focus on our group's achievements in studying nanocontainers from both ABA and ABC amphiphilic block copolymers.