Point load effect on the buried polyolefin pipes lifetime

Polymer pipe lifetime is conventionally estimated by internal pressure test. However, important for service are also other types of loading as: additional bending, different type of external loading from sand embedding, or effect of the residual stresses. One of the dangerous type of loading is so‐called “point load” caused, for example, by stones in the soil. The present article is focused on the numerical prediction of this effect on the pipe lifetime. For the lifetime estimation of a polymer pipe under point loading, an approach based on combination of numerical calculation and experimental measurements was used. A special numerical algorithm, which optimizes modeled crack front shape according to the real one during simulation of crack propagation, was proposed. Finally, an analytical relationship for the estimation of fracture parameters of propagating crack across the pipe wall crucial for the pipe lifetime estimation is presented in the paper. A significant reduction of the residual lifetime was found for the cracked pipe loaded by additional point load (consideration of indentation effects of stones in the soil) in comparison with pipe loaded by internal pressure only. The approach presented contributes to the safer service of polyolefin pipes. POLYM. ENG. SCI., 56:79–86, 2016. © 2015 Society of Plastics Engineers     

Interindividual–intergroup discontinuity reduction through the anticipation of future interaction.

Consistent with the role of a long-term perspective in reducing the tendency of intergroup relations to be more competitive than interindividual relations in the context of noncorrespondent outcomes, an experiment demonstrated that anticipated future interaction reduced intergroup but not interindividual competitiveness. Further results indicated that the effect was present only for groups composed of members high in abstractness (Openness–Intellect on the Big 5 Inventory and Intuition on the Myers–Briggs Type Inventory) who trusted their opponents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cumulative impacts of river engineering,Mississippi and Lower Missouri rivers

The goal of this study was to construct a large, data‐rich model to test hydrological responses to engineering modifications on over 3200 km of the Mississippi and Lower Missouri Rivers. We compiled model explanatory variables from a geospatial database quantifying construction of all bridges, wing dikes, bendway weirs, levees, artificial meander cutoffs, channel constriction and navigational dams over the past 100–150 years. Response variables were derived from 68 rated and un‐rated hydrologic stations in the study area, with responses analysed across a range of discharges from within‐channel flows up to moderate floods. Correlation analysis, multiple linear regression and stepwise regression analyses document strong and consistent responses to construction history, both in individual reach‐scale models and systemwide. Meander cutoffs are associated with degradation and acceleration of flow that has reduced stages across the full discharge range. Navigational dams on the Upper Mississippi River increased low‐flow stages and flood levels to a lesser extent, with little or no post‐dam change. One of the strongest signals was the hydrologic response to wing‐dike construction, which resulted in large back‐water increases in stage upstream of wing dikes and mixed effects downstream, including the overlapping effects of incision and velocity losses. Levees were associated with local flow concentration, overbank storage loss and floodplain conveyance loss depending on reach‐scale conditions. The results presented here (1) quantify incremental and cumulative hydrologic responses to a range of engineering activities and (2) provide an empirical tool for verifying and assessing hydraulic and other models of river‐system change. Copyright © 2009 John Wiley & Sons, Ltd.     

Erfahrungen mit Online-Wahlen für Vereinsgremien

Die Gesellschaft für Informatik e.V. (GI) führte bereits 2004 Online-Wahlen für ihre Vereinsgremien ein. über die dabei gewonnenen Erfahrungen berichtet der vorliegende Beitrag aus Sicht der Anwender, des Herstellers und des begleitenden Expertenarbeitskreises.     

High Intensity Drying of M.G. Paper

ABSTRACT

The technological properties of paper are strongly influenced by the drying conditions. This is the case in particular with M.G. paper and machine performance is limited largely for quality reasons. Therefore, the question as to which extent the drying conditions influence the process of drying and the paper quality is of major importance for industry.

Unlike the results already published, tests were carried out with a laboratory machine operating on a continuous basis, with high drying rates, short retention time and application of combined contact/ convectional drying. The kinds of stock used were waste paper containing wood, bleached long-fiber magnefite pulp and unbleached long-fiber sulphate pulp with a basis weight ranging between 37 and 75 g/m2.     

Optimization in risk management

Our purpose is to indicate how optimization concepts and techniques can be combined with probabilistic risk analysis to structure and solve risk management problems. Cost-optimal and risk-minimizing models are formulated in both deterministic and stochastic settings: the approach proposed is illustrated by several examples.     

Simulations and experiments of open hole tension tests – Assessment of intra-ply plasticity,damage, and localization

Laminated composites with various layups of unidirectional carbon fiber reinforced epoxy are investigated by numerical modeling and experimental testing. Open hole tension configurations are studied with special considerations of the non-linear behavior of the plies. Computational predictions are based on an anisotropic constitutive material law which includes plasticity and damage, the latter comprise hardening as well as softening. Experimental evaluations include a 3D image correlation photogrammetry system for capturing the strain fields of the sample surfaces.     

Interindividual-Intergroup Discontinuity as a Function of Trust and Categorization: The Paradox of Expected Cooperation.

Two experiments used a 3-choice variation of the prisoner's dilemma game to explore the paradoxical implications of expected cooperation of other groups and individuals for competitiveness and cooperativeness. Experiment 1 found that an experimental manipulation of opponent trustworthiness influenced the tendency of both groups and individuals to cooperate but had no significant effect on the tendency of groups and individuals to compete-possibly because of the perceived unfairness of competing with a trustworthy other. Experiment 2 found that an experimental manipulation of categorization increased the tendency of same-category groups and individuals to cooperate (as in Experiment 1) and also increased the tendency of same-category groups, but not individuals, to compete (unlike in Experiment 1). It was further found that the tendency of same-category groups to compete more than same-category individuals was relatively stronger for participants high in guilt proneness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transient increase of pancreatic enzymes evoked by apomorphine in Parkinson's disease

In one of our first patients with severely disabling and fluctuating Parkinson's disease (PD) we observed a transient pancreatic enzymes increase 6 months after continuous apomorphine therapy. Since this adverse effect had not been previously reported, we systematically investigated the course of pancreas and liver functions in response to apomorphine: laboratory and neurological assessments were conducted before initiation of apomorphine therapy, during the increment phase up to the optimal motor effective level and at all follow-up visits. We found in five out of 29PD patients a transient increase of pancreatic enzymes during the initial phase of continuous subcutaneous apomorphine application. Peaks of pathological plasma levels were apparent from the first day up to the fifth day after apomorphine initiation, and returned to normal levels within 10 days in all 5 patients. Otherwise, this pancreatic enzymes increase was not accompanied by any raising in plasma levels of corresponding liver enzymes. No pathological signs in the endoscopic-retrograde cholangiopancreatography, the abdominal ultrasonography and the computed tomography of the abdomen were found in any of the affected PD patients. Furthermore, there was no evidence of pancreato-hepatal risk factors in the previous history in any of the PD patients studied. With respect to the course of PD, no differences were obtained upon comparison of affected and non-affected PD patients. Considering the patients' history, clinical course and current knowledge about the effect of apomorphine on pancreato-hepatal function, we conclude that a possible cumulative pathomechanism between transient pancreato-hepatal enzymes and continuous applied apomorpine, especially in the titrating phase, might cause this adverse event in about 20% of PD patients treated with apomorphine continuously.