301   Expansion of Evergreen Conifers to the Larch-Dominated Zone and Climatic Trends Expansion of Evergreen Conifers to the Larch-Dominated Zone and Climatic Trends V. I. Kharuk, M. L. Dvinskaya, K. J. Ranson;S. T. Im    2005 The expansion of so-called evergreen conifers (EGCs), including Siberian stone pine, spruce, and fir, along the transect oriented from the boundary of the larch-dominated zone (LDZ; mixed forests of the Yenisei Ridge) to its center has been studied. The normalized dispersal coefficient calculated as Ki = (ni – Ni)/(ni + Ni), where ni and Ni are the relative numbers of the ith species in the undergrowth and the upper layer, respectively, serves as an indicator of the expansion. It has been... 查看全文

302   Prediction of sulfide stress cracking in high-strength tubulars Prediction of sulfide stress cracking in high-strength tubulars    1994 It is important to systematically assess the severity of a sour environment for susceptibility to sulfide stress cracking (SSC). A prediction system was established based upon SSC as a phenomenon of hydrogen embrittlement (HE). The content of H entering into steel (HFe) could be predicted from the hydrogen sulfide (H2S) concentration and hydrogen ion (H+) concentration by the equation: HFe (in ppm) = 13×(H+×H2S)0.26. SSC failure stress decreased with increases in HFe for any combinat... 查看全文

303   Member strength by inelastic lateral buckling Member strength by inelastic lateral buckling    2002 This paper develops a simple advanced method of designing steel members against out-of-plane failure, in which reduced elastic moduli are used In an out-of-plane buckling analysis to model the effects of high moment, residual stresses and geometrical Imperfections on yielding. The reduced moduli are derived from the basic beam and column strength curves of the Australian steel code AS4100 (SA, 1998). The strengths predicted for simply supported beams in uniform. bending are exactly the same as t... 查看全文

304   STRENGTH DIFFERENTIAL AND BAUSCHINGER EFFECTS IN SiC-Al COMPOSITES. STRENGTH DIFFERENTIAL AND BAUSCHINGER EFFECTS IN SiC-Al COMPOSITES.    1987 An investigation was undertaken to determine the effect of an average elastic residual stress on the strength differential and the Bauschinger effects in SiC-Al alloy composites. It was found that the compressive yield stress of the composites was greater than the tensile yield stress for whisker- and platelet-reinforced composites but, for composites containing spherical SiC reinforcement, the compressive yield stress was slightly less than the tensile yield stress. The experimentally observed ... 查看全文

305   Amphibole-bearing basalts from the submarine volcano Kick’em-Jenny in the lesser antilles Island arc Amphibole-bearing basalts from the submarine volcano Kick’em-Jenny in the lesser antilles Island arc H. Sigurdsson;J. B. Shepherd    1974 An oceanographic survey by H.M.S. Hecla of the 1974 active submarine volcano (12°18′N and 61°38′W) revealed a crater at 190 m below sea level and bottom-sampling yielded fresh olivine basalt pyroclastics with phenocrysts of olivine, plagioclase and clinopyroxene. Megacrysts of amphilbole, up to 16 modal percent, are subsilicic and nepheline-normative ferroan pargasites. The mineral assemblage Ol+Cpx+Pl+Amph appears to have been in equilibrium in the KickR... 查看全文

306   Adsorption of Hexadecyltrimethylammonium Bromide to Mica:  Nanometer-Scale Study of Binding-Site Competition Effects Adsorption of Hexadecyltrimethylammonium Bromide to Mica:  Nanometer-Scale Study of Binding-Site Competition Effects William A. Ducker* and Erica J. Wanless†    1998 We have changed the structure of an adsorbed surfactant layer by modifying the nature of the interface in situ. Muscovite mica contains surface anions that can bind to a variety of cations in aqueous solution. Using an atomic force microscope (AFM), we have investigated the influence of the adsorption of the salts HBr, KBr, and N(CH2CH3)4Br on the adsorption of hexadecyltrimethylammonium bromide (CTAB) to mica. In the absence of salt, at twice the bulk critical micelle concentration, CTAB initia... 查看全文

307   Guide on the selection of appropriate laboratory stress levels for the flow number test Guide on the selection of appropriate laboratory stress levels for the flow number test    2011 This study examines the use of the triaxial shear strength parameters (c and /) in providing guidelines for selecting the appropriate laboratory stress level for the flow number test of asphalt mixtures. The approach is based on the concept that the flow number (tertiary flow) is inversely related to the applied stress-to-strength ratio of the material. The correlation of the flow number with the stress-to-strength ratio can provide a good estimate of the stress level that will yield tertiary fl... 查看全文

308   Evaluation of hardness-yield strength relationships for bulk metallic glasses Evaluation of hardness-yield strength relationships for bulk metallic glasses    2006 The applicability of various hardness-yield strength ( H - y ) relationships currently available in the literature for bulk metallic glasses (BMGs) is investigated. Experimental data generated on ZrHf-based BMGs in this study and those available elsewhere on other BMG compositions are used to validate the models. A modified expanding-cavity model, proposed earlier by the authors, is extended to propose a new H - y relationship. Unlike previous models, the proposed model takes into account, not o... 查看全文

309   On Iterative Solutions of General Coupled Matrix Equations On Iterative Solutions of General Coupled Matrix Equations Feng Ding;Tongwen Chen    0 In this paper we study coupled matrix equations, which are encountered in many systems and control applications. First, we extend the well-known Jacobi and Gauss--Seidel iterations and present a large family of iterative methods, which are then applied to develop iterative solutions to coupled Sylvester matrix equations. The basic idea is to regard the unknown matrices to be solved as parameters of a system to be identified and to obtain the iterative solutions by applying a hierarchical identif... 查看全文

310   Effects of sanguinaria in fluoride-containing dentifrices on the remineralisation of subsurface carious lesion in vitro Effects of sanguinaria in fluoride-containing dentifrices on the remineralisation of subsurface carious lesion in vitro Amid I. Ismail    2011 Objective: The purpose of this study was to investigate the potential cariostatic benefits of dentifrice containing both fluoride (F) and sanguinaria (SG) in a silica abrasive formula using the microbial de- and re-mineralisation cycle model. Methods: Samples of bovine tooth enamel were embedded in resin, polished, exposed to a lactate carbopol buffer system for 44 hours, and divided into one control and five test groups of 12 specimens each by randomised blocks with VHN stratification. Surface ... 查看全文

311   A prediction model of IASCC initiation stress for bolts in PWR core internals A prediction model of IASCC initiation stress for bolts in PWR core internals    2010 A model of IASCC initiation stress for bolts of core internals in pressurized water reactors was developed considering differences in material property changes due to irradiation and material conditions. Assuming that IASCC initiation was controlled by grain boundary composition and yield strength, these values for each specimen of post-irradiation IASCC initiation tests were calculated by physical kinetic models considering dose rate, temperature, material composition and surface hardening. The... 查看全文

312   Predicting yield strengths and effusion rates of lava domes from morphology and underlying topography Predicting yield strengths and effusion rates of lava domes from morphology and underlying topography    2004 To investigate the effects of slope on the morphology of lava domes, laboratory experiments were conducted with a PEG-kaolin slurry erupted into cold water on slopes ranging from 0 to 60°. In each experiment the slope, effusion rate, and water temperature were varied, producing four distinct morphologies: spiny, lobate, platy, and no-crust. Each morphology is correlated with ΨB and slope, where ΨB is defined as the ratio of the timescale of solidification to the timescale of advectio... 查看全文

313   Administration of chlorhexidine to persons with mental retardation residing in an institution: Patient acceptance and staff compliance Administration of chlorhexidine to persons with mental retardation residing in an institution: Patient acceptance and staff compliance Amid I. Ismail    2008 Chlorhexidine is beneficial in maintaining the oral health of persons diagnosed with mental retardation. Proper daily oral administration, however, depends upon the compliance of Caregivers as well as patient acceptance. If caregivers are non-compliant or if patients are overly resistant to daily applications of chlorhexidine, its proven benefits will not be realized. This study evaluated two methods of chlorhexidine administration for patient acceptance and direct-care staff compliance among 44... 查看全文

314   Yield strength of two ductile phase alloys Yield strength of two ductile phase alloys    1993 The experimentally determined σy-∫β curves of the yield strength of two ductile phase alloys as afunction of volume fraction exhibit different shapes depending on the arrangement (or phase contiguity) of the constituent phases. An approach has been developed for predicting the yield strength of two ductile phase alloys. This approach can take into account the effects of microstructural parameters, such as volumefraction, grain size, and phase contiguity, on the yield strength. The... 查看全文

315   Iterative three-dimensional expectation maximization restoration of single photon emission computed tomography images: Application in striatal imaging Iterative three-dimensional expectation maximization restoration of single photon emission computed tomography images: Application in striatal imaging Pierre Gantet;Pierre Payoux;Cynthia Majorel;Jean-Paul Esquerré;Anna Celler;Daniel Gourion;Dominikus    0 Single photon emission computed tomography imaging suffers from poor spatial resolution and high statistical noise. Consequently, the contrast of small structures is reduced, the visual detection of defects is limited and precise quantification is difficult. To improve the contrast, it is possible to include the spatially variant point spread function of the detection system into the iterative reconstruction algorithm. This kind of method is well known to be effective, but time consuming. We hav... 查看全文

316   Influence of the yield-to-tensile strength ratio on the failure assessment of corroded pipelines Influence of the yield-to-tensile strength ratio on the failure assessment of corroded pipelines    2003 It is well known that both the yield strength and the tensile strength of a material have significant effect on the failure behavior. of pipelines. Thus it can be anticipated that the yield-to-tensile strength (Y/T) is closely related to the strain hardening behavior. of the material, and it also influences the failure behavior. This paper theoretically explores the influence of T/Y (the inverse of Y/T) ratio on the failure pressure of pipelines with or without corrosion defects. Based on the in... 查看全文

317   Polyhedral CeO2 Nanoparticles: Size-Dependent Geometrical and Electronic Structure Polyhedral CeO2 Nanoparticles: Size-Dependent Geometrical and Electronic Structure Cristina Paun†, Olga V. Safonova‡, Jakub Szlachetko‡, Paula M. Abdala§, Maarten Nachtegaal‡, Jacinto    2012 Ceria-based materials have many interesting applications including catalysis, fuel cells, and biology. The size- and shape-dependent changes in the catalytic properties of nanoceria are often attributed to stabilization Ce3+ defects on the nanoparticle surface. In this paper, we have performed a systematic analysis of the structure of polyhedral CeO2 nanoparticles of 2–10 nm, under ambient conditions, using a combination of transmission electron microscopy, X-ray diffraction, and X-ray spectrosc 查看全文

318   Alkaline Cleavage of 2,3-Dibromo-2-butene-1,4-diammonium Salts Alkaline Cleavage of 2,3-Dibromo-2-butene-1,4-diammonium Salts T. A. Saakyan, A. Kh. Gyul'nazaryan, N. O. Markaryan;S. T. Kocharyan    2005 Decomposition of N,N,N,N′,N′,N′-hexamethyl-2,3-dibromo-2-butene-1,4-diammonium diiodide in alcoholic alkali gives ammonium salts containing a 4,4-dialkoxy-2-butynyl group rather than the corresponding 1,4-elimination products. 查看全文

319   Alkali-rich intrusive rocks in the Qinghai-Xizang Plateau and its vicinities as exemplified by Kuganzi and Taihe plutons Alkali-rich intrusive rocks in the Qinghai-Xizang Plateau and its vicinities as exemplified by Kuganzi and Taihe plutons Yuquan Zhang;Yingwen Xie    1997 The alkali-rich intrusive rocks in the Qinghai-Xizang Plateau can be divided into two series in terms of dark-colored rock-forming minerals, petrochemical composition and trace elements: ∣) sodic alkaline series rocks consisting of alkaline rocks and alkali granite which contain dark-colored minerals, such as aegirine augite, aegirine and riebeckite, and being petrochemically enriched in alkali and sodium but low in Ca, Sr and Ba; ║) potassic alkaline series r... 查看全文

320   Alkali volcanism of the Bathymetrists Seamounts chain (Central Atlantic): Description and comparison Alkali volcanism of the Bathymetrists Seamounts chain (Central Atlantic): Description and comparison A. A. Peyve;S. G. Skolotnev    2009 查看全文

321   Viscosity, yield stress, remolded strength, and liquidity index relationships for sensitive clays Viscosity, yield stress, remolded strength, and liquidity index relationships for sensitive clays    1988 Remolded strength values can be predicted for soils with a liquidity index as high as 6. For a liquidity index varying from 2 to 5, the remolded undrained shear strength and plastic viscosity vary from about 90 to 5 Pa and from 200 to 7 mPa·s respectively. It has been observed that most sensitive clays behave either as a Bingham or a Casson fluid, the latter behavior. being related to less sensitive clays of higher pore-water salinities. Increasing the salt content from 0.5 to 30 g/L modif... 查看全文

322   Enamel mottling in a non-fluoride community in England Enamel mottling in a non-fluoride community in England    2012 Abstract— In 1974–75 an assessment of mottling in incisor teeth was carried out on a random sample of 13- to 14-year-old children in Liverpool, England. The number of children examined was 463. All of these children were born and had lived in Liverpool when the fluoride content of the water supply had averaged 0.12 parts/106. The mouth prevalence of mottling was 42.5%. The tooth prevalence of mottling was 9.6%. There was no sex difference. The data obtained was compared with those of... 查看全文

323   Study on yield strength and bending behavior. of bolted T-stub connections Study on yield strength and bending behavior. of bolted T-stub connections    2007 In this paper the yield strength and the deformation behavior. of bolted T-stub connections on the plate failure mode were investigated. As for the yield strength, it can be evaluated by a assumption of plastic hinges at around the T-stub web and at around the bolt. It became clear by FEM analysis that the plastic hinge location at bolt side was influenced by the T-stub flange thickness and the bolt placement. As for the deformation behavior. of connections, in order to predict load-displacement... 查看全文

324   Prediction of the strength of mineral-addition concrete using regression analysis Prediction of the strength of mineral-addition concrete using regression analysis    2010 The aim of this study was to develop a method for estimating concrete strength through non-destructive testing (NDT) methods. 27 different concrete mixtures were prepared with additions of high-volume fly ash and blastfurnace slag in place of Portland cement. Tests were then conducted to determine compressive strength (CS), splitting tensile strength (STS), flexural tensile strength (FTS), rebound number (RN) and ultrasonic pulse velocity (UPV) at 3, 7, 28, 90 and 180 days after preparation. The... 查看全文

325   An improved application technique of the adaptive probabilistic neural network for predicting concrete strength An improved application technique of the adaptive probabilistic neural network for predicting concrete strength    2009 Recently, the probabilistic neural network (PNN) has been applied to the prediction of concrete compressive strength. PNN has the advantage over the conventional neural networks (NN) by utilizing lesser time in determining the network architecture and in training. Moreover, PNN yields probabilistic viewpoints and deterministic classification results. However, an important factor in the estimation results, the smoothing parameter, is a user-defined constant and deciding its value is a crucial par... 查看全文

326   The correlation between hardness and yield strength of hard materials The correlation between hardness and yield strength of hard materials    2005 The correlation between hardness, H, and yield strength, Y, for hard materials is reexamined using an analytical approach to provide a physical interpretation, which explains the trends observed. Existing analytical predictions using the analogy of the spherical cavity fail to reproduce experimental and finite element results because the accommodation of the intrusion of the indenter due to surface deformation is not taken into account, while experiments made here and elsewhere indicate that the... 查看全文

327   Self-consolidating concrete filled steel tube columns - Design equations for confinement and axial strength Self-consolidating concrete filled steel tube columns - Design equations for confinement and axial strength    2006 This paper compares the performance of axially loaded concrete filled steel tube (CFST) columns cast using a conventionally vibrated normal concrete (NC) and a novel self-consolidating concrete (SCC) made with a new viscosity modifying admixture (VMA). A total of sixteen columns with a standard compressive strength of about 50 MPa for both SCC and NC were tested by applying concentric axial load through the concrete core. Columns were fabricated without and with longitudinal and hoop reinforceme... 查看全文

328   Residual strength prediction of aircraft fuselages using crack-tip opening angle criterion Residual strength prediction of aircraft fuselages using crack-tip opening angle criterion    2002 Ductile tearing simulation and residual strength prediction of wide-body, lap-jointed fuselage panels are conducted. The damage configurations of the fuselage panels consist of a single lead crack and a lead crack with small multiple-site damage (MSD). The crack-tip opening angle fracture criterion and elastic-plastic finite element analysis are used to control stable crack advancement under conditions of general yielding. Thin-shell finite elements are used to model the fuselage structures exce... 查看全文

329   The mechanical properties of BHP structural sections The mechanical properties of BHP structural sections    1990 Capacity design of steel seismic resistant structures relies on the accurate prediction of material properties as well as the determination of yielding behaviour with the respect to both location and impressed loading. Since the mechanical properties of hot rolled steel sections are influenced by composition, rolling and cooling history, the effect of section size on the yield strength distribution was investigated. The mechanical properties of structural sections manufactured to AS 1204, Grade ... 查看全文

330   Acylation of Dibenzo-18-crown-6 with Alkali-metal Acetates in Polyphosphoric Acid Acylation of Dibenzo-18-crown-6 with Alkali-metal Acetates in Polyphosphoric Acid N. Zh. Saifullina;A. K. Tashmukhamedova    2005 The acylation of dibenzo-18-crown-6 by lithium, sodium, and potassium acetates in polyphosphoric acid was studied. Complexes of dibenzo-18-crown-6 with the acetates were obtained. A new method is proposed for the production of mono- and diacetyldibenzo-18-crown-6 by the reaction of dibenzo-18-crown-6 complexes with metal acetates in polyphosphoric acid. 查看全文

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