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Selected AbstractsStatistical performance analysis of seismic-excited structures with active interaction controlEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 7 2003Yunfeng Zhang Abstract This paper presents a statistical performance analysis of a semi-active structural control system for suppressing the vibration response of building structures during strong seismic events. The proposed semi-active mass damper device consists of a high-frequency mass damper with large stiffness, and an actively controlled interaction element that connects the mass damper to the structure. Through actively modulating the operating states of the interaction elements according to pre-specified control logic, vibrational energy in the structure is dissipated in the mass damper device and the vibration of the structure is thus suppressed. The control logic, categorized under active interaction control, is defined directly in physical space by minimizing the inter-storey drift of the structure to the maximum extent. This semi-active structural control approach has been shown to be effective in reducing the vibration response of building structures due to specific earthquake ground motions. To further evaluate the control performance, a Monte Carlo simulation of the seismic response of a three-storey steel-framed building model equipped with the proposed semi-active mass damper device is performed based on a large ensemble of artificially generated earthquake ground motions. A procedure for generating code-compatible artificial earthquake accelerograms is also briefly described. The results obtained clearly demonstrate the effectiveness of the proposed semi-active mass damper device in controlling vibrations of building structures during large earthquakes. Copyright © 2003 John Wiley & Sons, Ltd. [source] Indices for bioavailability and biotransformation potential of contaminants in soilsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2004Washington J. Braida Abstract Bioavailability is an important consideration in risk assessment of soil contaminants and in the selection of appropriate remediation technologies for polluted sites. The present study examined the bioavailability and biodegradation potential of phenanthrene with respect to a pseudomonad in 15 different soils through separate measurements of mineralization, transformation, and desorption to a polymeric infinite sink (Tenax®) after 180-d sterile pre-equilibration with phenanthrene. Fractions strongly resistant to desorption and mineralization at long times were evident in all cases. After correcting for bioconversion (moles mineralized per mole transformed) determined in aqueous particle-free soil extracts, a correlation was found between the biotransformation-resistant fraction and the Tenax desorption-resistant fraction. Indices are proposed to assess bioavailability (BAt) and biotransformation potential (BTPt) of a compound in a soil based on parallel desorption and degradation studies over a selected period t. The BAt is the ratio of moles biotransformed to moles desorbed to an infinite sink, and it reflects the biotransformation rate relative to the maximal desorption rate. Values of BA30 (30-d values) ranged from 0.64 (for dark gray silt loam) to 1.12 (Wurtsmith Air Force Base [AFB] 2B, Oscoda, MI, USA). The BTPt is the ratio between moles biotransformed and moles of contaminant remaining sorbed after maximal desorption. The BTPt provides an indication of the maximum extent of biotransformation that may be expected in a system, assuming desorption is a prerequisite for biodegradation. Values of BTP30 ranged between 0.3 (Wurtsmith AFB 1B) and 13 (Mount Pleasant silt loam, NY, USA). The combination of BAt and BTPt provides insights regarding the relationship between physical availability (desorption) and biological processes (biotransformation kinetics, toxicity, other soil factors) that occur during biodegradation and are suggested to represent the remediation potential of the chemical. The BA30 values less than 0.9 and BTP30 values less than five indicate poor potential for site remediation. [source] EFFECT OF SURFACTANT GEL AND GUM COMBINATIONS ON DOUGH RHEOLOGICAL CHARACTERISTICS AND QUALITY OF BREADJOURNAL OF FOOD QUALITY, Issue 5 2004M.H. AZIZI ABSTRACT Sodium stearoyl-2-lactylate (SSL), diacetyl tartaric acid esters of monoglyceride (DATEM), glycerol monostearate (GMS) and distilled glycerol monostearate (DGMS) surfactant gels were made with water. Addition of surfactant gels decreased water absorption by the bread while xanthan, karaya, guar and locust bean gums increased the same. Only DGMS or GMS and gum combinations further improved water absorption. All the gums except for guar along with surfactant gels improved dough stability. Both surfactant gels and gums improved the extensograph dough properties of wheat flour to varying degrees. Alveograph characteristics of wheat flour improved to varying extents with surfactant gels while the gums influenced the viscoelastic properties in differing ways. Different combinations of surfactant gels and gums showed varied influences on rapid visco analyzer characteristics of wheat flour. Both surfactant gels and gums improved the bread making quality. Among surfactants, SSL in combination with gums, and among gums locust bean in combination with surfactant gels improved the bread making quality of wheat flour to a maximum extent. [source] Timing and style of Late Pleistocene glaciation in the Queer Shan, northern Hengduan Mountains in the eastern Tibetan Plateau,JOURNAL OF QUATERNARY SCIENCE, Issue 6 2010Liubing Xu Abstract Glacial landforms and sediments provide evidence for the existence of two Late Pleistocene major glacial advances in the Queer Shan, northern Hengduan Mountains in the eastern Tibetan Plateau. In the current study, optically stimulated luminescence and electron spin resonance dating results reveal that the two glacial advances occurred during Marine Isotope Stage (MIS) 3 and the Last Glacial Maximum (LGM) in MIS 2, respectively. Geomorphic evidence shows that the glacial advance during MIS 3 was more extensive than that in MIS 2. This glacial advance is synchronous with other glaciated areas in the Himalaya and Tibet, but contrasts with global ice volumes that reached their maximum extent during the LGM. Glaciers in the Queer Shan are of the summer accumulation type and are mainly fed by precipitation from the south Asian monsoon. Palaeoclimate proxies show that during MIS 3 the south Asian monsoon strengthened and extended further north into the Tibetan Plateau to supply more precipitation as snow at high altitudes. This in turn led to positive glacier mass balances and caused glaciers to advance. However, during the LGM, despite cooler temperature than in MIS 3, the weakened south Asian monsoon and the associated reduced precipitation were not as favourable for glacier expansion as in MIS 3. Copyright © 2010 John Wiley & Sons, Ltd. [source] Calendar year age estimates of Allerød,Younger Dryas sea-level oscillations at Os, western NorwayJOURNAL OF QUATERNARY SCIENCE, Issue 5 2004Øystein S. Lohne Abstract A detailed shoreline displacement curve documents the Younger Dryas transgression in western Norway. The relative sea-level rise was more than 9,m in an area which subsequently experienced an emergence of almost 60,m. The sea-level curve is based on the stratigraphy of six isolation basins with bedrock thresholds. Effort has been made to establish an accurate chronology using a calendar year time-scale by 14C wiggle matching and the use of time synchronic markers (the Vedde Ash Bed and the post-glacial rise in Betula (birch) pollen). The sea-level curve demonstrates that the Younger Dryas transgression started close to the Allerød,Younger Dryas transition and that the high stand was reached only 200,yr before the Younger Dryas,Holocene boundary. The sea level remained at the high stand for about 300,yr and 100,yr into Holocene it started to fall rapidly. The peak of the Younger Dryas transgression occurred simultaneously with the maximum extent of the ice-sheet readvance in the area. Our results support earlier geophysical modelling concluding a causal relationship between the Younger Dryas glacier advance and Younger Dryas transgression in western Norway. We argue that the sea-level curve indicates that the Younger Dryas glacial advance started in the late Allerød or close to the Allerød,Younger Dryas transition. Copyright © 2004 John Wiley & Sons, Ltd. [source] Comparison of rural and non-rural students undertaking a voluntary rural placement in the early years of a medical courseMEDICAL EDUCATION, Issue 3 2000Article first published online: 25 DEC 200 Objective The experiences of rural and non-rural students undertaking a voluntary rural placement in the early years of a medical course were compared. Method Eighty percent (28) of the rural and 70% (114) of the non-rural students completed a post-placement questionnaire. Result The two groups did not differ on their overall rating of the placement, whether they felt welcome, adequacy of the time with doctors or their rating of the accommodation provided. However, 46% (13) of the rural students reported the placement had changed their feelings towards rural practice to the maximum/almost maximum extent compared with only 24% (27) of the non-rural students. [source] Characterising relict cryogenic macrostructures in mid-latitude areas of the USA with three-dimensional ground-penetrating radarPERMAFROST AND PERIGLACIAL PROCESSES, Issue 3 2009James Doolittle Abstract Ground-penetrating radar (GPR) has considerable potential for the detection and identification of sediment-filled wedges and relict polygonal patterns in mid-latitude areas. Relict cryogenic macrostructures have been described previously both within and outside the maximum extent of the Late Wisconsinan glacial border in many regions of the USA. The features were formed under climatic conditions associated with permafrost and periglacial conditions and provide evidence of climate change. In this study, buried relict cryogenic macrostructures were identified with GPR. On some two-dimensional GPR (2D GPR) records, boundaries with the host materials are indistinguishable or blurred resulting in the features being overlooked, misinterpreted and/or imprecisely delineated. Three-dimensional GPR (3D GPR) was able to delineate buried networks of sediment-filled wedges and provided more meaningful information than 2D radar records. When supplemented with adequate ground-truth observations, GPR offers considerable potential for imaging, interpreting and mapping near-surface cryogenic macrostructures in former periglacial environments. Copyright © 2009 John Wiley & Sons, Ltd. [source] An example of a test method for vent sizing,OPPSD/SPI methodologyPROCESS SAFETY PROGRESS, Issue 2 2002Charles S. Poteet III An alternative methodology to that of United Nations, Appendix 5, Sample Method, has been developed by the Organic Peroxides Producers Safety Division of the Society of the Plastics Industry (OPPSD/SPI) to assure the safe emergency venting of organic peroxides in an approved container. The methodology is applicable for designing a new container for an existing or new organic peroxide. Bench-scale testing with a 10 liter vessel determined the maximum pressure pulse (spike) generated during a thermal decomposition/overpressurization vs. the ultimate, structural strength of the container measured and/or calculated. The methodology has been tested full scale with a United Nations 6(c) fuel fire. Container deformation, so long as there is no fragmentation, is permitted with the proviso that the container be retired from service following an incident. The methodology, as developed, reflects advances in technology while "harmonizing" to a maximum extent with the United Nations, Appendix 5, Sample Method. [source] JOINT BIDDING, GOVERNANCE AND PUBLIC PROCUREMENT COSTS:A CASE OF ROAD PROJECTS,ANNALS OF PUBLIC AND COOPERATIVE ECONOMICS, Issue 3 2009Antonio Estache ABSTRACT§:,To utilize public resources efficiently, it is important to take advantage of competition in public procurement auctions to the maximum extent. Joint bidding is a common practice that potentially facilitates competition. By pooling financial and experiential resources, more firms are expected to enter the market, but it will also directly reduce competition if more than one bidder who is solely qualified makes a coalition. In theory joint bidding may or may not be beneficial to auctioneers, depending on the model. The paper empirically examines the impacts of joint bidding on firms' entry as well as bidding behaviour, using data on public road projects in developing countries. It shows that coalitional bids, in particular by local firms, would be competitive, but foreign joint ventures would undermine competition. It is also found that good governance can encourage firms' entry into the tendering and facilitate joint bidding practices. [source] Co-evolution of the premaxilla and jaw protrusion in cichlid fishes (Heroine: Cichlidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010C. DARRIN HULSEY The ability of Perciform fishes to protrude their jaw has likely been critical to the trophic diversification of this group, which includes approximately 20% of all vertebrates. The length of the ascending process of the premaxilla is thought to influence the maximum extent that cichlids and other Perciforms protrude their oral jaw. Using a combination of morphometrics, kinematics, and new phylogenetic hypotheses for 20 Heroine cichlid species, we tested the evolutionary relationship between the length of the premaxillary ascending process and maximum jaw protrusion. In this clade, the length of the ascending process of the premaxilla ranged from 11.6,32.7% with respect to standard length whereas maximum jaw protrusion ranged from 3.5,23.4% with respect to standard length. The evolutionary relationships among the Heroine cichlids obtained from the genetic partitions cytochrome b, S7, and RAG1 showed limited concordance. However, correlations between the length of the ascending process and maximum jaw protrusion were highly significant when examined as independent contrasts using all three topologies. Evolutionary change in the length of the ascending process of the premaxilla is likely critical for determining the amount of jaw protrusion in Perciform groups such as cichlid fishes. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 619,629. [source] Amplified fragment length polymorphism fingerprints support limited gene flow among social spider populationsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2009DEBORAH SMITH We used DNA fingerprints to determine whether the population structure and colony composition of the cooperative social spider Stegodyphus dumicola are compatible with requirements of interdemic (,group') selection: differential proliferation of demes or groups and limited gene flow among groups. To investigate gene flow among groups, spiders were collected from nests at 21 collection sites in Namibia. Analysis of molecular variance showed a small but highly significant differentiation among geographic regions (,PT = 0.23, P = 0.001). Thirty-three nests at four collection sites (6,10 spiders per nest, 292 individual spiders) were investigated in more detail to evaluate variation within and among colonies and among collection sites. In these 33 nests, an average of 15% of loci (fingerprint bands) were polymorphic among nestmates; 16% of observed variance was partitioned among collection sites, 48% among nests within a collection site, and 36% among individuals within nests. Spatial autocorrelation analyses of spiders at three collection sites showed that the maximum extent of detectable spatial autocorrelation among individuals was approximately 30 m, indicating dispersal over greater distances is not typical. These results indicate limited gene flow among nests, as well as spatial structuring at the level of regions, local populations, and nests, compatible with interdemic selection. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 235,246. [source] Lipase-mediated Acidolysis of Fully Hydrogenated Soybean Oil with Conjugated Linoleic AcidJOURNAL OF FOOD SCIENCE, Issue 1 2004J. Ortega ABSTRACT: Interesterification (acidolysis) of fully hydrogenated soybean oil (melting point = 69.9 °C) with conjugated linoleic acid (CLA) was carried out in a batch reactor at 75 °C. Lipases from Candida antarctica, Rhizomucor miehei, Pseudomonas sp., and Thermomyces lanuginosus were used at 5% (wt/wt) of the total substrate load. The lipase from Rhizomucor miehei produced the fastest reaction rates, and the greatest extent of incorporation of CLA residues in acylglycerols was achieved in 12 h. Lipases from C. antarctica and T. lanuginosus produced slower initial rates, and maximum extents of incorporation of CLA residues were achieved in 24 h. The lipase from Pseudomonas sp. produced the slowest initial rate. The corresponding maximum extent of incorporation was reached in 48 h. Differential scanning calorimetry analysis of the triacylglycerol (TAG) fractions produced by C. antarctica, R. miehei, and T. lanuginosus lipases after purification by solid phase extraction showed little variation in melting point (60.4 °C, 62.8 °C, and 60.1 °C, respectively). By contrast, the corresponding TAG fraction produced by the Pseudomonas sp. lipase melted at 48.4 °C. The positional distribution of the TAGs produced by the lipase from Pseudomonas sp. differed appreciably from those produced by the other enzymes. [source] | ||||||||||||||||