Lateral Performance of Full-Scale Bridge Abutment Wall with Granular Backfill

Bridge abutments typically contain a backwall element that is designed to break free of its base support when struck by a bridge deck during an earthquake event and push into the abutment backfill soils. Results are presented for a full-scale cyclic lateral load test of an abutment backwall configured to represent the dimensions (1.7?m height), boundary conditions, and backfill materials (compacted silty sand) that are typical of California bridge design practice. An innovative loading system was utilized that operates under displacement control and that assures horizontal wall displacement with minimal vertical displacement. The applied horizontal displacement ranged from null to approximately 11% of the wall height (0.11H). The maximum earth pressure occurred at a wall displacement of 0.03H and corresponded to a passive earth pressure coefficient of Kp = 16.3. The measured force distribution applied to the wall from hydraulic actuators allowed the soil pressure distribution to be inferred as triangular in shape and the mobilized wall-soil interface friction to be evaluated as approximately one-third to one-half of the soil friction angle. Post-test trenching of the backfill showed a log-spiral principal failure surface at depth with several relatively minor shear surfaces further up in the passive wedge. The ultimate passive resistance is well estimated by the log-spiral method and a method of slices approach. The shape of the load-deflection relationship is well estimated by models that produce a hyperbolic curve shape.     

Liberals and conservatives rely on different sets of moral foundations.

How and why do moral judgments vary across the political spectrum? To test moral foundations theory (J. Haidt & J. Graham, 2007; J. Haidt & C. Joseph, 2004), the authors developed several ways to measure people’s use of 5 sets of moral intuitions: Harm/care, Fairness/reciprocity, Ingroup/loyalty, Authority/respect, and Purity/sanctity. Across 4 studies using multiple methods, liberals consistently showed greater endorsement and use of the Harm/care and Fairness/reciprocity foundations compared to the other 3 foundations, whereas conservatives endorsed and used the 5 foundations more equally. This difference was observed in abstract assessments of the moral relevance of foundation-related concerns such as violence or loyalty (Study 1), moral judgments of statements and scenarios (Study 2), “sacredness” reactions to taboo trade-offs (Study 3), and use of foundation-related words in the moral texts of religious sermons (Study 4). These findings help to illuminate the nature and intractability of moral disagreements in the American “culture war.” (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Major depressive disorder is associated with attenuated cardiovascular reactivity and impaired recovery among those free of cardiovascular disease.

Objective: To examine cardiovascular reactivity and recovery to laboratory stress among a naturalistic sample of individuals diagnosed with major depressive disorder (MDD) and healthy control participants. Prospective evidence suggests that MDD confers risk for cardiovascular disease equal to or greater than the risk associated with depressed mood. Enhanced cardiovascular reactivity has been proposed as a mechanism explaining increased risk, but data are inconsistent as to whether depressed individuals exhibit enhanced or attenuated reactivity. Further, few studies have examined appraisal and recovery differences. Design: Participants diagnosed with MDD (N = 25) and healthy control participants (N = 25) engaged in a cardiovascular reactivity protocol including 2 tasks, each followed by a brief recovery period. Main outcome measures: Blood pressure, heart rate, pre-ejection period, cardiac output and total peripheral resistance were assessed. Appraisals of tasks were assessed prior to each task. Results: Depressed participants exhibited significantly less systolic blood pressure, heart rate, and cardiac output reactivity during speech, less heart rate reactivity during mirror tracing, and less heart rate recovery after speech and mirror tracing than controls. Depressed participants appraised the tasks as more demanding, threatening, and stressful and reported being less able to cope than controls. Appraisals were related to heart rate reactivity, but appraisals did not mediate the relationship between depression group and reactivity. Conclusion: Impaired recovery rather than exaggerated cardiovascular reactivity may partially explain the increased prospective cardiovascular disease risk in depressed individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Architecture with Legs

Dreaming of developing the Thames Estuary, Ian Abley and Jonathan Schwinge went to see the Maunsell Sea Forts, built off the coast of Herne Bay, Kent, in 1942. Here they met members of Project Redsand, a charitable organisation that aims to preserve the forts as a public museum, and which has so far received encouragement from both industry and government departments.     

Visualization of active biomass distribution in a BGAC fluidized bed reactor using GFP tagged Pseudomonas putida F1

A favorable microenvironment for biofilm growth on GAC particles was shown using green fluorescent protein (GFP) as a marker for a phenol degrading bacterium, Pseudomonas putida F1. The dispersion of P. putida F1 in a biofilm covering granulated activated carbon (GAC) particles was monitored and compared to a biofilm on non-activated granular carbon particles. Laser scanning confocal microscopy (LSCM) micrographs of the biofilms taken from two fluidized bed reactors operating under identical conditions, showed higher fluorescent green areas in the GAC biofilm, especially close to the GAC surface. Quantitative analysis of the biofilm by COMSTAT, a three-dimensional biofilm structure analysis program, showed higher biomass concentration and higher viability in the GAC covered biofilm vs. the non-activated carbon biofilm. In addition, better effluent quality was measured for the BGAC reactor, which strongly suggests a significantly larger biofilm surface area available to the substrate, as opposed to that of the non-activated carbon carrier reactor.     

Composition of chlorinated hydrocarbon contaminants among major adipose tissue depots of polar bears (Ursus maritimus) from the Canadian high Arctic

Monitoring of environmental contaminants in Canadian Arctic polar bears (Ursus maritimus) typically has used superficial adipose tissue samples collected as part of controlled native subsistence hunts. However, little attention has been paid to the compositional difference in contaminants that may exist among the major adipose depots that are routinely collected. To address this knowledge gap, we investigated the profiles and concentrations of chlorinated hydrocarbon contaminants (CHCs), including major polychlorinated biphenyl (PCB) congeners and organochlorine (OC) pesticides and metabolites, in six major adipose depots (i.e. superficial, inter-muscular and intra-abdominal regions) obtained from adult male polar bears in the vicinity of Resolute Bay, Canadian high Arctic. Concentrations and congener patterns of PCBs (20 congeners) and OCs (14 compounds; chlordanes and dichlorodiphenyltrichloroethanes and metabolites, chlorinated benzenes, hexachlorocyclohexane isomers, octachlorostyrene and dieldrin) were found to be relatively uniform throughout the adipose tissue of male polar bears. The only exception was the inter-muscular adipose depot from the cervical region, which was characterized, compared to other major depots routinely sampled, by lower proportions of higher-chlorinated and recalcitrant congeners such as CB170/190, 180, 194 and 206, and higher contribution of the lower-chlorinated PCBs, CB47, 74 and 99. No difference in the OC makeup and concentrations was found among the adipose depots investigated. In view of this, we conclude that the determination of CHCs in adipose tissue of polar bears from any major depots, with the potential exception of the fat under the neck muscles, would give a representative picture of the overall CHC composition and concentrations in polar bear fat for purpose of trend monitoring.     

电弧炉粉尘等温还原的动力学研究

为使还原条件与实际电弧炉生产相接近,在等温条件下对电弧炉粉尘球团的还原过程动力学进行了研究。电弧炉粉尘与还原剂碳和粘接剂石灰均匀混合后制粒,经干燥后将球闭置于恒定温度的加热炉中,利用电子称定时对球团重量进行检测。金属还原率的计算中,考虑了球团的失重、铅和锌在高温下挥发。经研究,电弧炉粉尘的还原分为二个阶段,还原初期由化学反应控制而还原后期由扩散控制,并建立了每一阶段的还原动力学方程,确定了有关的动力学参数表观活化能和频率因子。     

Fabrication of Long Lengths of Epitaxial Buffer Layers on Biaxially Textured Nickel Substrates Using a Continuous Reel-to-Reel Dip-Coating Unit

A low-cost, nonvacuum, solution precursor route has been developed to produce epitaxial oxide buffer layers of Eu₂O₃ or La₂Zr₂O₇ on biaxially textured Ni (100) tapes. A reel-to-reel continuous dip-coating unit consisting of a constant-tension tape transport system attached to a controlled atmosphere furnace was fabricated. Nickel tapes were pulled through a 2-methoxyethanol solution of europium methoxyethoxide/acetate or lanthanum zirconium methoxyethoxide. The double-sided dip-coated tapes were then annealed in a preheated furnace at 1000°–1100°C with a high flow rate of Ar/H₂ (4%) gas. The dip-coated buffers were dense, continuous, crack-free, and epitaxial with a single cube texture. A critical current ( J _c) of >1 MA/cm² at 77 K and self-field was obtained for YBa₂Cu₃O_7-δ (YBCO) films with a layer sequence of YBCO ( ex situ BaF₂ process)/CeO₂ (sputtered)/YSZ (sputtered)/Eu₂O₃ (dip-coated)/nickel. We have produced 1–2 m lengths of epitaxial buffer layers on textured nickel substrates using a nonvacuum process for the first time.     

Fast ping‐pong arbitration for input–output queued packet switches

Input–output queued switches have been widely considered as the most feasible solution for large capacity packet switches and IP routers. In this paper, we propose a ping‐pong arbitration scheme (PPA) for output contention resolution in input–output queued switches. The challenge is to develop a high speed and cost‐effective arbitration scheme in order to maximize the switch throughput and delay performance for supporting multimedia services with various quality‐of‐service (QoS) requirements. The basic idea is to divide the inputs into groups and apply arbitration recursively. Our recursive arbiter is hierarchically structured, consisting of multiple small‐size arbiters at each layer. The arbitration time of an n‐input switch is proportional to log₄?n/2? when we group every two inputs or every two input groups at each layer. We present a 256×256 terabit crossbar multicast packet switch using the PPA. The design shows that our scheme can reduce the arbitration time of the 256×256 switch to 11 gates delay, demonstrating the arbitration is no longer the bottleneck limiting the switch capacity. The priority handling in arbitration is also addressed. Copyright © 2001 John Wiley & Sons, Ltd.