Analysis and optimization of weakly coupled thermoelastoplastic systems with applications to weldment design

A systematic approach for the design of weakly coupled thermoelastoplastic systems is presented. The Newton–Raphson iteration method is used in the solution process so that analytic design sensitivity formulations may be efficiently derived via the direct differentiation technique. The derived formulations are suitable for finite element implementations. Analysis and sensitivity analysis capabilities are combined with numerical optimization to form an optimum design algorithm. To demonstrate the algorithm, we optimally design a weldment with respect to manufacturing and service life aspects.     

Efficient and accurate waveguide mode computation using BI‐RME and Lanczos methods

In this paper, a special purpose algorithm for solving large eigenvalue problems based on the Lanczos method is successfully applied to an engineering problem: the electromagnetic analysis and design of passive waveguide devices. For dealing with such complex problems, the boundary integral‐resonant mode expansion (BI‐RME) technique has been recently proposed. This technique solves integral equations (IEs) through the well‐known method of moments (MoM), thus leading to structured eigenvalue problems. These problems frequently become very large when solving complex arbitrary geometries with high accuracy. In such cases, the eigenvalue problem cannot be efficiently solved with standard methods by means of personal computers, essentially due to CPU time and memory allocation requirements. In this paper, we propose an alternative technique, based on the Lanczos method, for the fast and accurate solution of large BI‐RME generalized eigenvalue problems. The novel theoretical aspects of this approach, as well as the impacton the original BI‐RME formulation, are described. Comparative benchmarks are also successfully presented for the full‐wave analysis and design of real passive microwave devices. Copyright © 2005 John Wiley Sons, Ltd.     

Peridynamic modeling of concrete structures

The peridynamic model described in Silling (Silling, S.A., 1998. Reformation of Elasticity Theory for Discontinuous and Long-Range Forces, SAND98-2176. Sandia National Laboratories, Albuquerque, NM), being a central-force model, is limited to modeling materials with a Poisson's ratio of 1/4. In this paper, the peridynamic model is generalized by adding pairwise peridynamic moments to simulate linear elastic materials with varying Poisson's ratios. The new model is called the “micropolar peridynamic model”. The micropolar peridynamic model is placed within a finite element context to enable efficacious application of boundary conditions and efficient computational solutions using an implicit, rather than an explicit solution algorithm. The implicit solution algorithm is suitable for quasistatic simulation of damage and cracking in concrete structures. With this new model, very simple tensile damage mechanisms at the micro structural (peridynamic) level are sufficient to explain a great deal of the microcracking (damage) and fracture mechanics observed in concrete structures. The new implementation appears to be computationally efficient.     

Does social dominance generate prejudice? Integrating individual and contextual determinants of intergroup cognitions.

Social dominance orientation (SDO) has been proposed as an important variable in the explanation of prejudice. We distinguish between three conceptualizations of SDO: SDO as a personality trait (personality model), SDO as a moderator of the effects of situational variables (Person X Situation model), and SDO as a mediator of the effect of social position on prejudice (group socialization model [GSM]). Four studies (N = 1,657) looking at the relations between social positions, SDO, and prejudice in a natural setting and in a laboratory setting provide strong support for the GSM. In contrast to previous correlational findings, there is evidence of a cause (dominant social position), an effect (prejudice increases), and a mediator (SDO). These results suggest new perspectives on the integration of individual and contextual determinants of prejudice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The determinants of cost efficiency of hydroelectric generating plants: A random frontier approach

This paper analyses the technical efficiency in the hydroelectric generating plants of a main Portuguese electricity enterprise EDP (Electricity of Portugal) between 1994 and 2004, investigating the role played by increase in competition and regulation. A random cost frontier method is adopted. A translog frontier model is used and the maximum likelihood estimation technique is employed to estimate the empirical model. We estimate the efficiency scores and decompose the exogenous variables into homogeneous and heterogeneous. It is concluded that production and capacity are heterogeneous, signifying that the hydroelectric generating plants are very distinct and therefore any energy policy should take into account this heterogeneity. It is also concluded that competition, rather than regulation, plays the key role in increasing hydroelectric plant efficiency.     

Branching and pruning: An optimal temporal POCL planner based on constraint programming

A key feature of modern optimal planners such as graphplan and blackbox is their ability to prune large parts of the search space. Previous Partial Order Causal Link (POCL) planners provide an alternative branching scheme but lacking comparable pruning mechanisms do not perform as well. In this paper, a domain-independent formulation of temporal planning based on Constraint Programming is introduced that successfully combines a POCL branching scheme with powerful and sound pruning rules. The key novelty in the formulation is the ability to reason about supports, precedences, and causal links involving actions that are not in the plan. Experiments over a wide range of benchmarks show that the resulting optimal temporal planner is much faster than current ones and is competitive with the best parallel planners in the special case in which actions have all the same duration.¹     

Rapid tamoxifen-induced inactivation of an estrogenic response is accompanied by a localized epigenetic modification but not by mutations

Ethidium was found to be efficiently cross-linked to DNA by glyoxal. Kinetic studies showed that the rate of the cross-linking reaction is strongly dependent on the glyoxal concentration. Comparative studies using a series of phenanthridines and acridines showed that NH2 groups at both the 2 and 7 positions on the phenanthridine ring are necessary for efficient cross-linking. Studies using synthetic polydeoxynucleotides showed that the 2-amino group of guanine is absolutely required for cross-linking. Fluorescence contact energy transfer and relative viscosity experiments showed that the cross-linked drug remains intercalated into DNA. DNA gel electrophoresis and melting studies demonstrated that cross-linked ethidium does not dissociate the DNA double helix to single strands.     

Effect of K-Casein Deglycosylation on the Acid Coagulability of Milk

ABSTRACT: The relationship between the content of N-acetylneuraminic acid residues of micellar K-casein and acid coagulability of milk was investigated. At 30 °C, partial deglycosylation of micellar K-casein does not significantly affect the content of micellar proteins, micellar surface charge, and micellar solvation. Casein micelles modified by the release of part of the N-acetylneuraminic acid residues showed a shorter acid gelation time, a higher rate of gel strengthening, and a higher final firmness. This enhancement in the gelation ability of the neuraminidase-treated casein micelles of milk should appear as the result of increase in number of hydrophobic sites on the surface of casein micelle due to enzymatic deglycosylation of micellar K-casein.     

Value of MRI, CT and findings in staging of gynecologic malignancies

PURPOSE: The present study was designed to compare the value of MRI, CT and clinical examination in local tumor staging of gynaecologic malignancies. PATIENTS AND METHODS: 99 patients with clinically suspected carcinoma of the cervix uteri, ovarian carcinoma or tumor recurrence after gynaecologic cancer underwent all three staging modalities. Furthermore CT and MRI were compared in detecting lymph node metastasis and peritoneal implants. RESULTS: MRI was superior to CT and clinical staging in local tumor staging with an accuracy of 77% for cervical carcinoma and of 88% for recurrent tumors, whereas CT achieved an accuracy of 65% and 55% and clinical staging 60% and 63% accuracy for carcinoma of the cervix and recurrent cancer. Especially for local staging of these two tumor entities MRI is very useful. MRI and CT reached comparable results in the detection of ovarian tumors with an accuracy of 73% for MRI and 69% for CI. Both imaging modalities also showed equal results in the detection of lymph node metastasis, so that primary the cost saving use of CT tumor staging for ovarian lesions and lymph node metastasis should be favoured.