Forging preform design with shape complexity control in simulating backward deformation

This paper presents a preform design method which employs an alternative boundary node release criterion in the finite element simulation of backward deformation of forging processes. The method makes use of the shape complexity factor which provides an effective measure of forging difficulty. The objective is to release die contacting nodes in a sequence which will minimize the geometric complexity throughout the backward deformation simulation. This is done by calculating the effect of releasing each of a select group of boundary element nodes at each finite element solution step. The particular detached node which results in the minimum shape complexity factor will be released for the current step. This process continues for each backward step until the last few nodes remain in contact. This design method is demonstrated through the simulated forging of an integrated blade and rotor turbine disk blank. A preform shape developed by this method is compared with an empirically designed preform. Performance parameters for comparison include die fill, flash volume, effective strain variance, frictional power and die load. Comparing the results of the forward simulations indicates improved performance of the preform design using FEM based backward deformation method over that of the empirical design.     

Phototoxicity and fluorotoxicity combine to alter the behavior of neutrophils in fluorescence microscopy based flow adhesion assays

The use of fluorescent probes that allow visualization of leukocyte-endothelial cell (EC) interactions has greatly informed our understanding of leukocyte recruitment. However, effects of these agents on the biological functions of leukocytes are poorly described, leading to concerns about the interpretation of such data. Here we used two flow-based neutrophil adhesion assays to compare the effects of phase contrast illumination (PCI) with high intensity illumination (HII) used for fluorescent microscopy, in the presence or absence of five commonly used fluorochromes. Isolated neutrophils were either (1) perfused across P-selectin to establish a population of rolling cells, which were subsequently activated with fMLP; or (2) perfused across EC activated with TNF-alpha. In the absence of fluorescent dyes, HII did not affect levels of leukocyte adhesion; however, subsequent neutrophil behavior was dramatically altered when compared with cells under PCI, for example, dramatically reducing their migration velocities. In the presence of fluorescent dyes, the effects of HII were exacerbated, although the precise nature of the biological effects of these probes was agent specific. Thus, for the first time, our experiments describe the effects of fluorescent microscopy on the separate stages of the neutrophil recruitment process and reveal a previously unsuspected effect of HII on neutrophil migration.     

The identification of highly chlorinated ethers and diethers in river sediment near an epichlorohydrin plant

In harbour sediment samples taken near an epichlorohydrin production plant, a series of highly chlorinated ethers and diethers were detected viz. three isomeric bis(dichloropropyl)ethers, several structurally closely related ethers with 9 carbon atoms (C₉ ethers), a number of C₁₂ ethers and diethers, and finally several C₁₅ ethers. The formation of this new class of ether compounds can be explained on the basis of the chemistry of the addition of HOCl to allylchloride. After initial addition of Cl⁻, a reactive intermediate is formed which may react with the product dichloropropanol, to give the C₆ ethers, or may polymerize with the starting compound allylchloride followed by reaction with the product, to give the C₉, C₁₂ and C₁₅ ethers.     

Fire evacuation skills: Cognitive-behavioral versus computer-mediated instruction

Fifty-six fourth-grade children participated in this study to assess three training procedures for relative effectiveness in acquiring fire emergency skills and attaining knowledge. The first training approach was behavioral, the second used animated graphics, and the third used still graphics. Each of the training groups was compared to a control group that received no treatment. Performance on dependent measures was assessed before and immediately after training. It was hypothesized that the behavioral and animated-graphics conditions would produce the greatest level of skill and knowledge acquisition. Results demonstrated a significantly higher level of fire emergency skill acquisition and knowledge attainment for both the behavioral and animated-graphics groups relative to the still-graphics group and the control group, which had no training. The value of using computer-mediated strategies for fire-safety skills training was demonstrated.     

节能减排：公用事业良性发展的新要求

节能减排是指节约能源和减少环境有害物排放。中国“十一五”规划纲要提出,“十一五”期间单位国内生产总值能耗降低20％左右,主要污染物排放总量减少10％。这是贯彻落实科学发展观、构建社会主义和谐社会的重大举措;是建设资源节约型、环境友好型社会,推进经济结构调整,转变增长方式的必由之路。节能减排工作也渗透于城市公用事业发展的各个方面。     

Sensitivity analysis based preform die shape design for net-shape forging

A sensitivity analysis method for preform die shape design in net-shape forging processes is developed in this paper using the rigid viscoplastic finite element method. The preform die shapes are represented by cubic B-spline curves. The control points or coefficients of B-spline are used as the design variables. The optimization problem is to minimize the zone where the realized and desired final forging shapes do not coincide. The sensitivities of the objective function, nodal coordinates and nodal velocities with respect to the design variables are developed in detail. A procedure for computing the sensitivities of history-dependent functions is presented. The remeshing procedure and the interpolation/transfer of the history-dependent parameters, such as effective strain, are stated. The procedures of sensitivity analysis based preform die design are also described. In addition, a method for the adjustment of the volume loss resulting from the finite element analysis is given in order to make the workpiece volume consistent in each optimization iteration. The method developed in this paper is used to design the preform die shape of H-shaped forging processes, including plane strain and axisymmetric deformations. The results show that a flashless forging with a complete die fill is realized using the optimized preform die shape.     

Contaminant blubber burdens in Atlantic bottlenose dolphins (Tursiops truncatus) from two southeastern US estuarine areas: Concentrations and patterns of PCBs, pesticides, PBDEs, PFCs, and PAHs

Polychlorinated biphenyls (PCBs), chlorinated pesticides (i.e., dichlorodiphenyltrichloroethane (DDT) and its metabolites, chlordanes (CHLs), dieldrin, hexachlorobenzene (HCB), and mirex), polybrominated diphenyl ethers (PBDEs), perfluorinated chemicals (PFCs), and polyaromatic hydrocarbons (PAHs) were measured in blubber biopsy samples collected from 139 wild bottlenose dolphins (Tursiops truncatus) during 2003-2005 in Charleston (CHS), SC and the Indian River Lagoon (IRL), FL. Dolphins accumulated a similar suite of contaminants with ∑ PCB dominating (CHS 64%, IRL 72%), followed by ∑ DDT (CHS 20%, IRL 17%), ∑ CHLs (CHS 7%; IRL 7%), ∑ PBDE (CHS 4%, IRL 2%), PAH at 2%, and dieldrin, PFCs and mirex each 1% or less. Together ∑ PCB and ∑ DDT concentrations contributed ∼ 87% of the total POCs measured in blubber of adult males. ∑ PCBs in adult male dolphins exceed the established PCB threshold of 17 mg/kg by a 5-fold order of magnitude with a 15-fold increase for many animals; 88% of the dolphins exceed this threshold. For male dolphins, CHS (93,980 ng/g lipid) had a higher ∑ PCBs geomean compared to the IRL (79,752 ng/g lipid) although not statistically different. In adult males, the PBDE geometric mean concentration was significantly higher in CHS (5920 ng/g lipid) than the IRL (1487 ng/g). Blubber ∑ PFCs concentrations were significantly higher in CHS dolphins. In addition to differences in concentration of PCB congeners, ∑ PBDE, TEQ, ∑ CHLs, mirex, dieldrin, and the ratios ∑ DDE/∑DDT and trans-nonachlor/cis-nonachlor were the most informative for discriminating contaminant loads in these two dolphin populations. Collectively, the current ∑ PCB, ∑ DDT, and ∑ PBDEs blubber concentrations found in CHS dolphins are among the highest reported values in marine mammals. Both dolphin populations, particularly those in CHS, carry a suite of organic chemicals at or above the level where adverse effects have been reported in wildlife, humans, and laboratory animals warranting further examination of the potential adverse effects of these exposures.     

Citation delay in interdisciplinary knowledge exchange

As part of a larger project to investigate knowledge flows between fields of science, westudied the differences in speed of knowledge transfer within and across disciplines. The agedistribution of references in three selections of articles was analysed, including almost 800.000references in journal publications of the United Kingdom in 1992, 700.000 references inpublications of Germany in 1992, and more than 11 million references in the world total ofpublications in 1998.The rate of citing documented knowledge from other disciplines appears to differ sharplyamong disciplines. For most of the disciplines the same ratio's are found in the three data sets.Exceptions show interesting differences in the interdisciplinary nature of a field in a country. Wefind a general tendency of a citation delay in case of knowledge transfer between different fieldsof science: citations to work of the own discipline show less of a time lag than citations to work ina foreign discipline. Between disciplines typical differences in the speed of incorporatingknowledge from other disciplines are observed, which appear to be relatively independent of timeand place: for each discipline the same pattern is found in the three data sets. The disciplinespecific characteristics found in the speed of interdisciplinary knowledge transfer may be point ofdeparture for further investigations. Results may contribute to explanations of differences incitation rates of interdisciplinary research.     

Ant colony optimisation of decision tree and contingency table models for the discovery of gene–gene interactions

In this study, ant colony optimisation (ACO) algorithm is used to derive near‐optimal interactions between a number of single nucleotide polymorphisms (SNPs). This approach is used to discover small numbers of SNPs that are combined into a decision tree or contingency table model. The ACO algorithm is shown to be very robust as it is proven to be able to find results that are discriminatory from a statistical perspective with logical interactions, decision tree and contingency table models for various numbers of SNPs considered in the interaction. A large number of the SNPs discovered here have been already identified in large genome‐wide association studies to be related to type II diabetes in the literature, lending additional confidence to the results.Inspec keywords: genetics, genomics, DNA, polymorphism, molecular biophysics, molecular configurations, ant colony optimisation, decision trees, bioinformatics, diseasesOther keywords: ant colony optimisation, decision tree, contingency table models, gene‐gene interactions, ACO algorithm, near‐optimal interactions, single nucleotide polymorphisms, SNP, genome‐wide association studies, type II diabetes     

Evidence-based management: using serial firm trials to improve diabetes care quality

BACKGROUND: The design of delivery systems that can truly conduct continuous quality improvement (CQI) as a routine part of clinical care provision remains a vexing problem. The effectiveness of the "computerized firm system" approach to chronic disease CQI was examined, with diabetes as the focus of a 5-year case study. METHODS: A large family medical center had been divided into two parallel group practices for reasons of efficiency. These frontline structures (also known as primary care "firms") were supported to serially adapt and evaluate selected CQI interventions by first introducing process changes on one firm but not the other and comparing the groups. Because all the required longitudinal data were contained in a computerized repository, it was possible to conduct these controlled "firm trials" in a matter of months at low cost. RESULTS: During a 3-year period, implementation of point-of-service reminders and a pharmacist out-reach program increased recommended glycohemoglobin (HbA1c) testing by 50% (p = 0.02) and reduced the number of diabetic patients inadequately controlled by 43% (p < 0.01). Following this outcome improvement, patients exhibited a 16% reduction in ambulatory visit rates (p = 0.04). The observed outcome improvement, however, was reversed during the subsequent 2 years, when staffing austerities forced by unrelated declines in clinic revenue caused the withdrawal of trial interventions. CONCLUSIONS: The processes and outcomes of diabetes care were improved, demonstrating that CQI and controlled trials are not mutually exclusive in moving toward the practice of evidence-based management. Health care systems can, by conducting serial firm trials, become learning organizations. CQI programs of all kinds will likely never flourish, however, until quality improvement and reimbursement mechanisms have become better aligned.