检索结果-南通市图书馆

Origin and geoc.e.istry of Pan-African granitoid rocks in the Gabal Um Shomer area,Southwestern Sinai,egypt

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese Journal Of Geoc.e.istry 2009年第2期28卷 125-135页

作者： e1-Tokhi m.m. musallum A. Amin b.m. Geology Department College of ScienceUnited Arab Emirates UniversityUnited Arab Emirates

Geological, petrological and geoc.e.ical studies indicated that there are two distinct types of granitoid rocks: older quartz diorites to granodiorite assemblage and younger granitoids, the latter occurring in two phases. The older granitoids have a meta-aluminous c.e.istry and a calc-alkaline charac.e., with high mgO, Fe2O3, TiO2, caO, P2O5, Sr and low SiO2, K2O, and Rb. Their major and trace elements data, together with low 87Sr/ 86Sr ratios (0.7029±0.0008) are indicative of I-type affinities. The second- and third-phase granitoids range from calc-alkaline to alkaline, respectively. The second-phase granitoids have a peraluminous c.e.istry and high Sr, ba, caO, mgO, Al2O3 and Ti2O and low SiO2, K2O, Nb, Y and Rb relative to the third-phase granitoids. The corundum normative nature and field observations suggested that it was formed by partial melting of the lower crust. The third-phase granitoids are alkaline in nature and charac.e.ized by higher SiO2, Rb, Y, Nb and lower mgO, Sr and ba values than the younger granitoids (phase Ⅱ). They are A-type granitoids which were generated from below or within the existing continental crust.

关键词：花岗岩类岩石地球化学西奈半岛过铝质花岗岩起源西南埃及石英闪长岩

Performance evaluation of up-flow anaerobic sludge blanket(UASb) reactor for treatment of paper mill wastewater

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sc.e.ces 2004年第2期16卷 194-198页

作者： m. mahadevaswamy b.m. Sadashiva murthy A.R. Girijamma Department of environmental engineering S.J.College of EngineeringDepartment of Environmental EngineeringS.J.College of EngineeringDepartment of Environmental EngineeringS.J.College of Engineering Mysore-570 006Karnataka StateIndiaMysore-570 006Karnataka StateIndiaMysore-570 006Karnataka StateIndia

The present study deals with the performance evaluation of the UASb reactor under varied organic loading rate(OLR) for the treatment of paper mill wastewater. The sludge granulation process started after 120 days from the start-up period. Sludge granules size was found to be 0 8 mm at OLR of 1 72 kgcOD/(m 3·d), which reac.e. maximum size of about 1 0 to 1 2 mm at OLR of 2 1 kgcOD/(m 3·d). At the end of initial OLR of 1 0 kgcOD/(m 3·d) the VSS concentration was 12 86 gVSS/L, which got inc.e.sed to 38 05 gVSS/L at the end of an OLR 2 1 kgcOD/(m 3·d). most of the times VFA recorded were well within the limit of VFA reported in anaerobic fermentation process. many times the pH observed was between 6 5 and 7 8, which is more favorable for any anaerobic process. It is also found that pH within the reactor inc.e.ses along with the height of reactor. The total maximum biogas production was found to be 0 40 L/gcOD removals at OLR of 2 1 kgcOD/(m 3·d) and the maximum bOD removal at this stage was observed to be 90%.

关键词： UASb biogas anaerobic digestion sludge loading rate organic loading rate

An integrated risk sensing system for geo-structural safety

在线全文

学校读者我要写书评

暂无评论

Journal of Rock mechanics and Geotechnical engineering 2017年第2期9卷 226-238页

作者： H.W. Huang D.m. Zhang b.m. Ayyub Key Laboratory of Geotechnical and Underground engineering Department of Geotechnical EngineeringTongji University Shanghai China center for Technology and Systems management Department of Civil and Environmental EngineeringUniversity of MarylandCollege ParkMDUSA

Over the last decades,geo-structures are experiencing a rapid development in *** potential risks inherent in the huge amount of construction and asset operation projects in china were well managed in the major project,*** project of Shanghai Yangtze tunnel in *** then,risk assessment of geostructures has been gradually developed from a qualitative manner to a quantitative ***,the current practices of risk management have been paid considerable attention to the assessment,but little on risk *** a result,the responses to risks occurrences after a comprehensive assessment are basically too *** this paper,a smart system for risk sensing incorporating the wireless sensor network(WSN) on-site visualization techniques and the resilience-based repair strategy was *** merit of this system is the real-time monitoring for geo-structural performance and dynamic pre-warning for safety of on-site *** sectional convergence,joint opening,and seepage of segmental lining of shield tunnel were monitored by the micro-electro-mechanical systems(memS) based *** light emitting diode(LeD) coupling with the above WSN system was used to indicate different risk levels on *** sensing the risks and telling the risks in real time,the geo-risks could be controlled and the safety of geo-structures could be assured to a certain ***,a resilience-based analysis model was proposed for designing the repair strategy by using the measured data from the WSN *** application and effic.e.cy of this system have been validated by two cases including Shanghai metro tunnel and underwater road tunnel.

关键词： Risk control Wireless sensor network(WSN) Geo-structure Resilience Robustness

Stability of fluid flow in a brinkman porous medium–A numerical study

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2014年第5期26卷 681-688页

作者： SHANKAR b.m. KUmAR Jai SHIVAKUmARA I.S. 吴朝安 Department of mathematics PES Institute of TechnologyBangalore 560 085India ISRO Satellite centre Bangalore 560 017India Department of mathematics Bangalore UniversityBangalore 560 001India Department of mechanical engineering The University of Hong Kong

The stability of fluid flow in a horizontal layer of brinkman porous medium with fluid viscosity different from effective viscosity is investigated. A modified Orr-Sommerfeld equation is derived and solved numerically using the c.e.yshev collocation method. The critical Reynolds number Re, the critical wave number ac and the critical wave speed cc are computed for various values of porous parameter and ratio of viscosities. based on these parameters, the stability charac.e.istics of the system are discussed in detail. Streamlines are presented for selec.e. values of parameters at their critical state.

关键词： brinkman model c.e.yshev collocation method hydrodynamic stability modified Orr-Sommerfeld equation

Strategies for inc.e.sing the capture, storage, and utilization of precipitation in semiarid regions

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2015年第8期14卷 1500-1510页

作者： b A stewart LIANG Wei-li Department of Agricultural Sc.e.ces West Texas A&M University Faculty of Agronomy Agricultural University of Hebei

crop production in semiarid regions is always challenging because of the high variability of amount and distribution of *** regions become more important each year, however, because the rapidly inc.e.sing and more prosperous world population seeks greater consumption of animal products（meat, milk and eggs） that requires additional grain to that consumed *** dry areas of the developing world where approximately 40% of the world population lives comprise about 40% of the earth＇s land *** production, particularly cereal grains, must inc.e.se in these areas to meet these growing *** yield of cereal crops is a function of the amount of water used for evapotranspiration（eT）, the portion of eT used for transpiration（T）, the units of water as T to produce 1 unit of biomass, and the harvest index（HI）.The most important factor is the amount of evapotranspiration not only because it is closely proportional to grain yield, but because it tends to also make the other factors more ***, even small inc.e.ses in eT can be *** for manipulating soil and plant conditions for inc.e.sing eT, and how additional eT affects the other factors, are discussed for water defic.e.t *** use of crop residues as mulch is highly beneficial but often insuffic.e.t in dryland regions or is required for animal feed and *** mulch, mainly restric.e. to china, has significantly inc.e.sed grain yields in dryland areas by dec.e.sing evaporation from the soil surface.

关键词： dryland farming water precipitation

Assortative mating and self-fertilization differ in their contributions to reinforcement, cascade speciation, and diversification

在线全文

学校读者我要写书评

暂无评论

current Zoology 2016年第2期62卷 169-181页

作者： Dean m. cASTILLO Amanda K. gibson Leonie c. mOYLe Department of biology 1001 East Third Street Indiana University Bloomington IN 47405 USA

cascade speciation and reinforcement can evolve rapidly when traits are pleiotropic and act as both signal/c.e.in nonrandom mating. Here, we examine the contribution of two key traits-assortative mating and self-fertilization--to reinforcement and （by extension） cascade speciation. First, using a population genetic model of reinforcement we find that both assortative mating and self-fertilization can make independent contributions to inc.e.sed reproductive isolation, consistent with reinforcement. Self-fertilization primarily evolves due to its 2-fold transmission advantage when inbreeding depression （d） is lower （d〈 0.45） but evolves as a function of the cost of hybridization under higher inbreeding depression （0.45 〈 d〈 0.48）. When both traits can evolve simultaneously, inc.e.sed self-fertilization often prohibits the evolution of assortative mating. We infer that, under specific conditions, mating system transitions are more likely to lead to inc.e.sed reproductive isolation and initiate cascade speciation, than assortative mating. based on the results of our simulations, we hypothesized that transitions to self-fertilization could contribute to clade-wide diversification if reinforcement or cascade speciation is common. We tested this hypothesis with comparative data from two different groups. consistent with our hypothesis, there was a trend towards uniparental reproduction being associated with inc.e.sed diversification rate in the Nematode phylum. For the plant genus mimulus, however, self-fertilization was associated with reduced diversification. Reinforcement driving speciation via transitions to self-fertilization might be short lived or unsustainable across macroevolutionary scales in some systems （some plants）, but not others （such as nematodes）, potentially due to differences in susceptibility to inbreeding depression and/or the ability to transition between reproductive modes.

关键词： speciation pleiotropy self-fertilization.

effects of Lead on pH and Temperature-Dependent Substrate-Activation Kinetics of ATPase System and its Protection by Thiol compounds in Rat brain

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

biomedical and environmental Sc.e.ces 1991年第4期4卷 441-451页

作者： b.RAJANNA c.S.c.e.TY T.c.stewart S.RAJANNA Department of Natural Sc.e.ce.Selma University Selma Al 36701 U. S. ADepartment of Natural Science.Selma University Selma Al 36701 U. S. ADepartment of Natural Science.Selma University Selma Al 36701 U. S. ADepartment of Computer Science and Mathematics Selma University Selma Al 36701 U. S. A

Lead (Pb) inhibited the activities of Na+ -K+ ATPase (Ic50= 2.0×10^(-6) m), K + -Para-Nitrophenyl phosphatase (PNPPase) (Ic50= 3.5×10^(-6) m) and [3H]-ouabain binding (Ic50 = 4.0×10^(-5) m) in rat brain P2 fraction. A variable temperature or pH significantly elevated the inhibition of Na+-K+ ATPase by Pb in buffered acidic, neutral and alkaline pH ranges. Noncompetitive inhibition with respect to activation of Na+ -K+ ATPase by ATP was indicated by a variation in Vmax values with no significant changes in Km values at any temperature studied. In the presence of Pb, for Na+ -K+ ATPase at pH 6.5 and 8.5, Vmax was dec.e.sed with an inc.e.se in Km values suggesting a mixed type of inhibition. Sulfhydryl agents such as dithiothreitol (DTT) and cvsteine (cyst), but not glutathione (GSH) offered varied levels of protection against Pb-inhibition of Na + -K+ ATPase at pH 7.5 and 8.5. The present data suggest that inhibition of Na+ -K+ ATPase by Pb is both temperature and pH-dependent. These results also indicate that Pb inhibited Na + -K + ATPase by interfering with phosphorylation of enzyme molecule and dephosphorylation of the enzyme-phosphoryl complex and exerted an effect similar to that of SH-blocking agents.

关键词： effects of Lead on pH and Temperature-Dependent Substrate-Activation Kinetics of ATPase System and its Protection by Thiol compounds in Rat brain ATPase pH

evaluation of stress intensity factors for bi-material interface cracks using displacement jump methods

在线全文

学校读者我要写书评

暂无评论

Acta mechanica Sinica 2017年第6期33卷 1051-1064页

作者： K. c. Nehar b. e. Hachi F. cazes m. Haboussi Laboratoire de développement en mécanique et matériaux (LDmm) Université de Djelfa PB 3117 Djelfa Algeria Laboratoire des Sc.e.ces des Procédés et des matériaux (LSPm) UPR 3407 CNRS Université Paris 13 Paris France

The aim of the present work is to investigate the numerical modeling of interfacial cracks that may appear at the interface between two isotropic.e.astic materials. The extended finite element method is employed to analyze brittle and bi-material interfacial fatigue crack growth by computing the mixed mode stress intensity factors(SIF). Three different approac.e. are introduced to compute the SIFs. In the first one, mixed mode SIF is deduced from the computation of the contour integral as per the classical J-integral method,whereas a displacement method is used to evaluate the SIF by using either one or two displacement jumps located along the crack path in the second and third approac.e.. The displacement jump method is rather classical for mono-materials,but has to our knowledge not been used up to now for a b.m.terial. Hence, use of displacement jump for charac.e.izing bi-material cracks constitutes the main contribution of the present study. Several benchmark tests including parametric studies are performed to show the effectiveness of these computational methodologies for SIF considering static and fatigue problems of bi-material structures. It is found that results based on the displacement jump methods are in a very good agreement with those of exact solutions, such as for the J-integral method, but with a larger domain of applicability and a better numerical effic.e.cy(less time consuming and less spurious boundary effect).

关键词： bi-material interface crack mixed mode stress intensity factor Displacement jump X-Fem Fatigue crack growth

conceptual design of an experiment to study dust destruction by astrophysical shock waves

在线全文

学校读者我要写书评

暂无评论

High Power Laser Sc.e.ce and engineering 2018年第3期6卷 9-14页

作者： m. J.-e. manuel T. Temim e. Dwek A. m. Angulo e X. belancourt R. e Drake c. c. Kuranz m. J. macDonald b. A. Remington General Atomics 3550 General Atomics Court San Diego CA 92121 USA Space Telescope Sc.e.ce Institute 3700 San Martin Drive Baltimore MD 21218 USA Observational cosmology Lab Code 665 NASA Goddard Space Flight Center Greenbelt MD 20771 USA climate and Space Sc.e.ce and engineering University of Michigan Ann Arbor M148109 USA Department of Physics University of California Berkeley CA 94720 USA Lawrence Livermore National Laboratory Livermore CA 94450 USA

A novel laboratory experimental design is described that will investigate the processing of dust grains in astrophysical shocks. Dust is a ubiquitous ingredient in the interstellar medium(ISm) of galaxies; however, its evolutionary cyc.e.is still poorly understood. especially shrouded in mystery is the effic.e.cy of grain destruction by astrophysical shocks generated by expanding supernova remnants. While the evolution of these remnants is fairly well understood, the grain destruction effic.e.cy in these shocks is largely unknown. The experiments described herein will fill this knowledge gap by studying the dust destruction effic.e.c.e. for shock velocities in the range ～10–30 km/s(μm/ns), at which most of the grain destruction and processing in the ISm takes place. The experiments focus on the study of grain–grain collisions by ac.e.erating small(～1 μm) dust partic.e. into a large(～5–10 μm diameter) population; this simulates the astrophysical system well in that the more numerous, small grains impact and collide with the large population. Facilities that combine the versatility of high-power optical lasers with the diagnostic capabilities of X-ray free-electron lasers, e.g., the matter in extreme conditions instrument at the SLAc National Ac.e.erator Laboratory, provide an ideal laboratory environment to c.e.te and diagnose dust destruction by astrophysically relevant shocks at the micron scale.

关键词： laboratory astrophysics shock waves dust destruction