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Shearfree Spherically Symmetric Fluid models

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Chinese Physics Letters 2012年第5期29卷 41-44页

作者： m.Sharif z.Yousaf Department of mathematics University of the PunjabQuaid-e-Azam CampusLahore-54590Pakistan

We attempt to discover some exact analytical models of the spherically symmetric spacetime of collapsing fluid under shearfree *** types of solution are considered:one is to impose a condition on the mass function,while the other is to restrict the *** obtain five exact models in total,and some of them satisfy the Darmoie conditions.

关键词： conditions. exact satisfy

Antioxidative Responses and metal Accumulation in Invasive Plant Species Growing on mine Tailings in zanjan, Iran

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Pedosphere 2011年第6期21卷 802-812页

作者： m.m.A.BOOJAR z.TAVAKKOLI Department of Biology Tarbiat Moalem University

Tailings of a Pb and zn mine as a metal-contaminated area （zone 1） with two pioneer plant species, Peganum harmala and zygophyllum fabago, were investigated and compared with a non-contaminated area （zone 2） in the vicinity. Total concentrations of Pb, zn, and Cu in the soil of zone 1 were 1 416, 2 217, and 426 mg kg-1, respectively, and all exceeded their ranges in the normal soils. The soil pH was in the neutral range and most of the physical and chemical characteristics of the soils from both zones were almost similar. The species z. fabago accumulated higher Cu and zn in its aerial part and roots than the normal plants. On the other hand, their concentrations did not reach the criteria that the species could be considered as a metal hyperaccumulator. The species P. harmala did not absorb metals in its roots; accordingly, the accumulation factor values of these metals were lower than 1. The contents of chlorophyll, biomass, malondialdehyde, and dityrosine in these two species did not vary significantly between the two zones studied. In zone 1, leaf vacuoles of z. fabago stored 35.6% and 43.2% of the total leaf Cu and zn, respectively. However, in this species, the levels of phytochelatins （PCs） and glutathione （GSH） and antioxidant enzyme activities were significantly higher in zone 1 than in zone 2. In conclusion, metal exclusion in P. harmala and metal accumulation in z. fabago were the basic strategies in the two studied pioneer species growing on the metal-contaminated zone. In response to metal stress, elevation in antioxidant enzyme activities, increases in the PCs and GSH levels in the aerial parts, and metal storage within vacuoles counteracted each other in the invasion mechanism of z. ]abago.

关键词： accumulation factor antioxidant enzymes glutathione metal stress phytochelatins

Computation of the Fractal Pattern in manganese Dendrites

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Chinese Physics Letters 2005年第8期22卷 2112-2115页

作者： z.merdan m.Bayirli DepartmentofPhysics GaziosmanpasaUniversityTokatTurkey

The images of manganese flowers (clusters) on the surface of the natural magnesium silicate substance are scanned and the pictures of them are transferred to computer atmosphere. By using these scanning parameters, the exponents of density correlation function and fractal dimension values are calculated. For all different groups between the least and the most dense in the samples, the correlation function exponents may range from 0.141 to 0.178 and the fractal dimension values may vary between 1.61 and 1.88. In addition, the manganese flowers are divided into seven different groups according to their smallest- and largest-density features. The formation of the natural manganese clusters (flowers, dendrites) on the surface of the magnesium silicate substance can be defined by using the deposition, diffusion and aggregation model.

关键词： DDA CO Pattern

A prediction model for the effective thermal conductivity of nanofluids considering agglomeration and the radial distribution function of nanoparticles

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Acta mechanica Sinica 2018年第3期34卷 507-514页

作者： z.m.zheng B.Wang School of Physics Sun Yat-Sen UniversityGuangzhou 510275China Instimt Franco-Chinois de l'Energie Nucleaire Sun Yat-Sen UniversityZhuhai 519000China

Conventional heat transfer fluids usually have low thermal conductivity, limiting their efficiency in many applications. many experiments have shown that adding nanosize solid particles to conventional fluids can greatly enhance their thermal conductivity. To explain this anomalous phenomenon, many theoretical investigations have been conducted in recent years. Some of this research has indicated that the particle agglomeration effect that commonly occurs in nanofluids should play an important role in such enhancement of the thermal conductivity, while some have shown that the enhancement of the effective thermal conductivity might be accounted for by the structure of nanofluids, which can be described using the radial distribution function of particles. However, theoretical predictions from these studies are not in very good agreement with experimental results. This paper proposes a prediction model for the effective thermal conductivity of nanofluids, considering both the agglomeration effect and the radial distribution function of nanoparticles. The resulting theoretical predictions for several sets of nanofluids are highly consistent with experimental data.

关键词： Nanofluid Thermal conductivity modeling Agglomeration Radial distribution function

Predicting the response of continuous RC deep beams under varying levels of differential settlement

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 686-700页

作者： m.z.NASER R.A.HAWILEH Glenn Department of Civil Engineering Clemson UniversityClemsonSC 29634USA Department of Civil Engineering American University of SharjahSharjahUnited Arab Emirates materials Science and Engineering Research Institute American University of SharjahSharjahUnited Arab Emirates

This paper investigates the effect of differential support settlement on shear strength and behavior of continuous reinforced concrete(RC)deep beams.A total of twenty three-dimensional nonlinear finite element models were developed taking into account various constitutive laws for concrete material in compression(crushing)and tension(cracking),steel plasticity(i.e.,yielding and strain hardening),bond-slip at the concrete and steel reinforcement interface as well as unique behavior of spring-like support *** models are first validated by comparing numerical predictions in terms of load-deflection response,crack propagation,reaction distribution,and failure mode against that of measured experimental data reported in *** the developed models were successfully validated,a parametric study was designed and *** parametric study examined number of critical parameters such as ratio and spacing of the longitudinal and vertical reinforcement,compressive and tensile strength of concrete,as well as degree(stiffness)and location of support stiffness to induce varying levels of differential *** study also aims at presenting a numerical approach using finite element simulation,supplemented with coherent assumptions,such that engineers,practitioners,and researchers can carry out simple,but yet effective and realistic analysis of RC structural members undergoing differential settlements due to variety of load actions.

关键词： concrete continuous beams deep beams finite element modeling support settlement

CATIONIC RING-OPENING POLYmERIzATION OF TETRAHYDROFURAN WITH KEGGIN-TYPE HETEROPOLYCOmPOUNDS AS SOLID ACID CATALYSTS

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Chinese Journal of Polymer Science 2010年第3期28卷 305-310页

作者： Ahmed Aouissi Salim salem Al-Deyab Hassan Al-Shehri Chemistry Department College of ScienceKing Saud UniversityRiyadhKSA

Three Keggin-type heteropolyanions, namely H3Pmo12O40-13H2O, （NH4）3Pmo12O40·4H2O and H3PW12O40·13H2O were prepared and tested in the ring-opening polymerization reaction of tetrahydrofuran. The effects of the counter-cation （H＋, NH4＋） and the peripheral atoms （mo, W） on the polymerization were investigated. It has been found that when the protons of H3Pmo12O40·13H2O were replaced by the ammonium cations the polymerization rate decreased dramatically. Whereas, when the peripheral atoms （mo） were replaced by their homologous （W）, the polymerization rate increased twofold. As for the viscosity average molecular weight （my） of polymer products, it was found that the high molecular weight （7930） was obtained by using H3PW12O40·13H2O. The molecular weight （my） obtained by H3Pmo12O40·13H2O and （NH4）H3Pmo12O40·13H2O was 6470 and 6810, respectively.

关键词： Tetrahydrofuran Heteropoly compounds Ring opening polymerization Cyclic ether Solid acid

Evaluating ultrasound signals of carbon steel fatigue testing using signal analysis approaches

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Journal of Central South University 2014年第1期21卷 232-241页

作者： m.m.Padzi S.Abdullah m.z.Nuawi S.m.Beden z.m.Nopiah Department of mechanical and materials Engineering Universiti Kebangsaan Malaysia

The application of ultrasound techniques to monitor the condition of structures is becoming more prominent because these techniques can detect the early symptoms of defects such as cracks and other *** early detection of defects is of vital importance to avoid major failures with catastrophic *** assessment of an ultrasound technique was used to investigate fatigue damage *** tests were performed according to the ASTm E466-96 standard with the attachment of an ultrasound sensor to the test *** 1045 carbon steel was used due to its wide application in the automotive industry.A fatigue test was performed under constant loading stress at a sampling frequency of 8 *** sets of data acquisition systems were used to collect the fatigue strain signals and ultrasound *** of the signals were edited and analysed using a signal processing *** methods were used to evaluate the signals,the integrated Kurtosis-based algorithm for z-filter technique(I-kaz) and the short-time Fourier transform(STFT).The fatigue damage behaviour was observed from the initial stage until the last stage of the fatigue *** results of the I-kaz coefficient and the STFT spectrum were used to explain and describe the behaviour of the fatigue damage.I-kaz coefficients were ranged from 60 to 61 for strain signals and ranged from 5 to 76 for ultrasound signals.I-kaz values tend to be high at failure point due to high amplitude of respective *** spectrogram displays the colour intensity which represents the damage severity of the strain signals.I-kaz technique is found very useful and capable in assessing both stationary and non-stationary signals while STFT technique is suitable only for non-stationary signals by displaying its spectrogram.

关键词： fatigue ultrasound signal analysis integrated Kurtosis-based algorithm for z-filter technique short-time Fouriertransform

CO_(2) capture using membrane contactors:a systematic literature review

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Frontiers of Chemical Science and Engineering 2021年第4期15卷 720-754页

作者： Sanaa Hafeez Tayeba Safdar Elena Pallari George manos Elsa Aristodemou zhien zhang S.m.Al-salem Achilleas Constantinou Division of Chemical and Energy Engineering School of EngineeringLondon South Bank UniversityLondon SE10AAUK medical Research Council Clinical Trials Unit University College LondonLondon WC1V 6LJUK Department of Chemical Engineering University College LondonLondon WCIE 7JEUK William G.Lowrie Department of Chemical and Biomolecular Engineering The Ohio State UniversityColumbusOH 43210USA Environment&Life Sciences Research Centre Kuwait Institute for Scientific ResearchSafat 13109Kuwait Department of Chemical Engineering Cyprus University of Technology Limassol 3036Cyprus

With fossil fuel being the major source of energy,CO_(2) emission levels need to be reduced to a minimal amount namely from anthropogenic *** consumption is expected to rise by 48%in the next 30 years,and global warming is becoming an alarming issue which needs to be addressed on a thorough technical ***,exploring CO_(2) capture using membrane contactor technology has shown great potential to be applied and utilised by industry to deal with post-and pre-combustion of CO_(2).A systematic review of the literature has been conducted to analyse and assess CO_(2) removal using membrane contactors for capturing techniques in industrial *** review began with a total of 2650 papers,which were obtained from three major databases,and then were excluded down to a final number of 525 papers following a defined set of *** results showed that the use of hollow fibre membranes have demonstrated popularity,as well as the use of amine solvents for CO_(2) *** current systematic review in CO_(2) removal and capture is an important milestone in the synthesis of up to date research with the potential to serve as a benchmark databank for further research in similar areas of *** study provides the first systematic enquiry in the evidence to research further sustainable methods to capture and separate CO_(2).

关键词： CO_(2)capture preferred reporting items for systematic reviews and meta-analysec membranc contactor absorbent

Disaster Collaborative Exercises for Healthcare Teamwork in a Saudi Context

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International Journal of Disaster Risk Science 2023年第2期14卷 183-193页

作者： mohammed Ali salem Sultan Amir Khorram-manesh Jarle Lφwe Sφrensen Johan Berlin Eric Carlstrōm model of Care Healthcare TransformationRegional Health DirectorateNajran66255Saudi Arabia Institute of Health and Care Sciences Sahlgrenska AcademyGothenburg University40530GothenburgSweden Institute of Clinical Sciences Sahlgrenska AcademyGothenburg University40530GothenburgSweden Gothenburg Emergency medicine Research Group(GEmREG) Sahlgrenska Academy41345GothenburgSweden USN School of Business University of South-Eastern Norway3199BorreNorway Department of Social and Behavioural Studies University West46186TrolhättanSweden

This study aimed to evaluate the development of healthcare teamwork during and after the collaboration tabletop exercises,through observation and interview *** and maturity theoretical models were employed to explain the collaborative challenges in teams that may suffer from unequally distributed power,hierarchies,and *** three-level collaboration tabletop exercises and the Command and control,Safety,Communication,Assessment,Treatment,Triage,Transport(CSCATTT)instrument,100 healthcare workers were observed during each step in the implementation of the CSCATTT instrument using two simulated *** results show a lack of integration and team maturity among participants in the first scenario,leading to the delayed start of the activity,task distribution,and decision *** shortcomings were improved in the second ***-depth interviews with 20 participants in the second phase of the study revealed improved knowledge and practical skills,self-confidence,and ability in team building within trans-professional groups in the second scenario,which in concordance with the integration theory,was due to the attempts made in the first ***,there was an improvement in the team’s maturity,which in concordance with the maturity theory,was due to the knowledge and practical skills during scenario *** results indicate the importance of continuous tabletop training,and the use of CSCATTT as a collaborative instrument,to promote the development of collaboration and to test the concept of preparedness.

关键词： Collaboration exercises Disaster education Emergency management Healthcare personnel training Saudi Arabia Teamwork