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Tilted global solar irradiance in Bahrain: an experimental study

cLEAN ENERGY 2024年第2期8卷 27-34页

作者： Vasilikos, N. Georgantopoulou, c. Alajaimi, H. Almajed, S. H. Ahmed, M. Mathioulakis, D. Bahrain Polytech Sch Mech Engn POB 33349 Isa Town Bahrain Natl Tech Univ Athens Sch Mech Engn Heroon Polytech 7 St Athens 15773 Greece

In the present work, tilted global solar irradiance data are presented and analysed, measured for a period of 1 year on the campus of Bahrain Polytechnic, Kingdom of Bahrain, from both a fixed photovoltaic panel and a moving one via a two-axis solar tracker. The fixed panel faces south with an angle of 26 degrees with respect to the horizontal, coinciding with the local geographical latitude. The second panel is moved by two motors, controlled by a global positioning system and suitable software so that the Sun's rays are perpendicular to the panel surface. A pyranometer is installed on each panel, recording the tilted global solar irradiance, stored by using a data logger. The analysis of the data obtained shows a 33% solar energy gain on an annual basis for the moving panel (2780 versus 2088 kWh/m2 on the fixed panel). More importantly, in June, when the energy demand in Bahrain is elevated due to the increased residential cooling loads, the solar energy received by the moving panel is 54.7% higher compared with that of the fixed panel. On a percentage basis, the increase in solar energy from the moving panel is profound in the early morning and late evening hours. Moreover, the reduction in the solar energy received by the fixed panel from May to June does not appear in the moving panel because of the adjustable orientation of the latter. Throughout the year, the mean daily solar power varies between 0.37 and 0.56 kW/m2 for the fixed panel, and 0.45 and 0.70 kW/m2 for the moving panel. In winter, solar energy fluctuations are elevated due to erratic weather conditions that present a peak standard deviation of 28% of the corresponding mean. The data presented are useful for potential solar investments in Gulf countries. Tilted global solar irradiance data are measured and analysed for a period of 1 year on the campus of Bahrain Polytechnic, Kingdom of Bahrain, from both a fixed photovoltaic panel and a moving one via a two-axis solar tracker. Graphical Abstract

关键词： tilted solar irradiance renewable energy solar tracking photovoltaic Gulf cooperation council countries SUN TRAcKING ENERGY SYSTEMS PANELS WORLD

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高、低核酸含量原核生物应对资源可利用性降低和原生动物选择性摄食的适应性策略

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中国科学：地球科学 2024年第6期54卷 1901-1913页

作者：胡晨余柳倩陈晓炜刘纪化张瑶 John BATT 肖喜林石蔷张锐骆庭伟焦念志徐大鹏厦门大学环境与生态学院厦门361102 近海海洋环境科学国家重点实验室厦门大学海洋与地球学院福建省海洋碳汇重点实验室厦门361102 Joint Lab for Ocean Research and Education(LORE)of Dalhousie University Canadaand Shandong University and Xiamen UniversityXiamen 361102China 香港科技大学(广州)地球与海洋大气科学学域广州510000 山东大学海洋研究院青岛266237 Department of Oceanography Dalhousie UniversityHalifaxNova Scotia B3H 4R2Canada 深圳大学高等研究院深圳518060 厦门大学碳中和创新研究中心厦门361102

原核生物在全球海洋生物地球化学循环中发挥重要作用,然而对它们不同生态亚群(即:高核酸(HNA)和低核酸(LNA)含量亚群)的丰度和代谢活性,以及它们的调控因素如何随着海洋环境条件的变化而变化,仍知之甚少.我们在117,000升的大体积培养体... 详细信息

原核生物在全球海洋生物地球化学循环中发挥重要作用,然而对它们不同生态亚群(即:高核酸(HNA)和低核酸(LNA)含量亚群)的丰度和代谢活性,以及它们的调控因素如何随着海洋环境条件的变化而变化,仍知之甚少.我们在117,000升的大体积培养体系中进行了73天的培养实验,深入研究HNA和LNA亚群对资源可利用性降低和原生动物选择性摄食随时间变化的动态响应.研究结果显示,当培养环境资源充足时, HNA亚群的代谢活性高于LNA亚群,但随着资源日益稀缺, HNA亚群代谢下降速度比LNA亚群快,从而使LNA亚群对原核生物活性的贡献稳步增加.与此同时,随着培养体系资源可利用性逐步降低,原生动物的摄食偏好从HNA亚群转向LNA亚群,使得LNA亚群对培养体系的碳流贡献增加.这些结果突显了LNA亚群在资源有限环境中的韧性,阐明了原生动物选择性摄食在资源条件变化时平衡不同亚群中的关键作用,并展示了在不同环境背景下原生动物和原核生物之间复杂的相互适应性.

关键词：微生物环大体积培养实验原核生物自上而下和自下而上调控作用碳流

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PHASE TRANSFORMATION AND cHARAcTERISTIcS IN FREcKLE AREAS FOR INcONEL 625 SUPERALLOY

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Acta Metallurgica Sinica(English Letters) 2005年第1期18卷 47-54页

作者： J.x.Dong M.c.Zhang Y.P.Zeng x.S.xie UniversityofScienceandTechnologyBeijing Beijing100083China

The freckle formation and their phase characterizatics in freckle areas were investigated by means of microstructure analysis approaches and a thermodynamic equilibrium phase calculation method in an Inconel 625 allay. These results show that in freckle areas a large number of M6c, Mc, Laves and δ phases precipitate in grain boundaries even within grain due to the enrichment and segregation of Mo and Nb during solidification, which results in almost of these freckle areas covered by these complex precipitated phases and induces small grains in freckle areas. Equilibrium phase and liquid segregation calculation can give a reasonable interpretation of the freckle feature for this alloy.

关键词： freckle superalloy Inconel 625 thermodynamic calculation

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Regulation of thermoelastic properties of concave-packaged DNA adsorption films and its relevant microcantilever detection signals

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Acta Mechanica Sinica 2021年第4期37卷 705-711,I0004页

作者： c.x.Wu N.H.Zhang c.Y.Zhang J.Z.Wu School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsShanghai 200072China

The packing patterns have close correlation with the thermoelastic properties of DNA adsorption films and the relevant detection signals of *** this paper,we investigate the influence of packing patterns on the thermoelastic properties of DNA adsorption films,the detection signals of microcantilevers and their temperature ***,the Parsegian's empirical potential based on a mesoscopic liquid crystal theory is employed to describe the interaction energy among coarse-grained DNA cylinders;then,the thought experiment method and the force balance method of nonlinear elastic network nodes are combined to characterize the elastic modulus,prestress and thermal expansion coefficient of DNA adsorption films;finally,based on an effective macroscopic continuum model for DNA microbeam deformation,we study the microcantilever resonance frequency shifts caused by DNA adsorptions and the temperature effect on the microcantilever static deflections,*** show that,compared with the convex-packaged,the re-entrant honeycomb packing pattern endows DNA adsorption films with a larger adjustable range of the elastic modulus and prestress,so as to make DNA-microcantilevers having an enhanced dynamic detection signal whereas a weaker response to temperature *** results are expected to provide a new option for the regulation design of DNA composite materials and microbeam sensors.

关键词： DNA-microbeam Packaging pattern Elastic property Thermal expansion coefficient Detection signal

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Mechanical properties of gas hydrate-bearing sediments during hydrate dissociation

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Acta Mechanica Sinica 2018年第2期34卷 266-274页

作者： x.H.Zhang D.S.Luo x.B.Lu L.L.Liu c.L.Liu Institute of Mechanics Chinese Academy of SciencesBeijing 100190China college of Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Gas Hydrate Ministry of Land and ResourcesQingdao 266071China Qingdao Institute of Marine Geology Qingdao 266071China

The changes in the mechanical properties of gas hydrate-bearing sediments(GHBS) induced by gas hydrate(GH) dissociation are essential to the evaluation of GH exploration and stratum instabilities. Previous studies present substantial mechanical data and constitutive models for GHBS at a given GH saturation under the non-dissociated condition. In this paper, GHBS was formed by the gas saturated method, GH was dissociated by depressurization until the GH saturation reached different dissociation degrees. The stress–strain curves were measured using triaxial tests at a same pore gas pressure and different confining pressures. The results show that the shear strength decreases progressively by 30%–90% of the initial value with GH dissociation, and the modulus decreases by 50% –75%. Simplified relationships for the modulus, cohesion, and internal friction angle with GH dissociated saturation were presented.

关键词： Gas hydrate-bearing sediments Dissociation Mechanical properties Shear strength Triaxial test

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Predicting temperature-dependent ultimate strengths of body-centered-cubic(Bcc)high-entropy alloys

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npj computational Materials 2021年第1期7卷 1384-1393页

作者： B.Steingrimsson x.Fan x.Yang M.c.Gao Y.Zhang P.K.Liaw Imagars LLc 2062 Thorncroft Drive Suite 1214HillsboroOR 97124USA Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996USA University of chinese Academy of Sciences Center of Materials Science and Optoelectronics EngineeringBeijing 100049China National Energy Technology Laboratory 1450 Queen Ave.SWAlbanyOR 97321USA Beijing Advanced Innovation center of Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China Qinghai Provincial Engineering Research center of High Performance Light Metal Alloys and Forming Qinghai UniversityXining 810016China Shunde Graduate School University of Science and Technology BeijingFoshan 528399China

This paper presents a bilinear log model,for predicting temperature-dependent ultimate strength of high-entropy alloys(HEAs)based on 21 HEA *** consider the break temperature,Tbreak,introduced in the model,an important parameter for design of materials with attractive high-temperature properties,one warranting inclusion in alloy *** reliable operation,the operating temperature of alloys may need to stay below *** introduce a technique of global optimization,one enabling concurrent optimization of model parameters over low-temperature and high-temperature ***,we suggest a general framework for joint optimization of alloy properties,capable of accounting for physics-based dependencies,and show how a special case can be formulated to address the identification of HEAs offering attractive ultimate *** advocate for the selection of an optimization technique suitable for the problem at hand and the data available,and for properly accounting for the underlying sources of variations.

关键词： alloys strength alloy

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The Reality of Baryonic Acoustic Oscillations

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Journal of Modern Physics 2024年第3期15卷 377-402页

作者： J. c. Botke Ronin Institute Montclair New Jersey USA

The initial idea for baryonic acoustic oscillations (BAO) came about during early efforts to understand the origin of galaxies by studying perturbed versions of the Friedmann-Robertson-Walker (FRW) model. In more recent times, the emphasis has shifted to the idea that 2-point galaxy correlations embedded in the distribution of matter by the BAO could be used as a standard ruler to fix the parameters of cosmological models. In this paper, we first consider the actual business of extracting the correlation length from large data sets of measured galaxy locations. To facilitate this process, we introduce a much-improved method for extracting the correlation peak from the data set. Fundamental to this process in any model is the use of a fiducial cosmological model to transition from redshift space to comoving coordinate space where the correlations actually exist. The belief is that the correlation length so determined can then be reverted to redshift space to fix the parameters of cosmological models. We show, however, that this process is circular and hence of no value whatsoever for fixing model parameters. All one obtains are the parameters of the model used to transition to comoving space in the first place. Finally, we present simple arguments that show that the idea of BAO being responsible for the structure of the universe, i.e. the cosmic web, is unworkable.

关键词： Baryonic Acoustic Oscillations Two-Point correlations cMB Anisotropy Early Universe Time-Varying curvature

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cO_2 adsorption using TiO_2 composite polymeric membranes:A kinetic study

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Journal of Environmental Sciences 2015年第9期27卷 163-171页

作者： Sarah Hafeez x.Fan Arshad Hussain c.F.Martín School of chemical and Materials Engineering (ScME) National University of Sciences & Technology Institute for Materials and Processes School of Engineering University of Edinburgh University of Aberdeen School of Engineering Fraser Noble Building King's College

cO2is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture cO2. Membrane gas separation is a fast growing cO2 capture technique, particularly gas separation by composite membranes. The separation of cO2 by a membrane is not just a process to physically sieve out of cO2 through the controlled membrane pore size. It mainly depends upon diffusion and solubility of gases, particularly for composite dense membranes. The blended components in composite membranes have a high capability to adsorb cO2. The adsorption kinetics of the gases may directly affect diffusion and solubility. In this study, we have investigated the adsorption behaviour of cO2 in pure and composite membranes to explore the complete understanding of diffusion and solubility of cO2 through membranes. Pure cellulose acetate（cA） and cellulose acetatetitania nanoparticle（cA-TiO2） composite membranes were fabricated and characterised using SEM and FTIR analysis. The results indicated that the blended cA-TiO2 membrane adsorbed more quantity of cO2 gas as compared to pure cA membrane. The high cO2 adsorption capacity may enhance the diffusion and solubility of cO2 in the cA-TiO2 composite membrane, which results in a better cO2 separation. The experimental data was modelled by Pseudo first-order, pseudo second order and intra particle diffusion *** to correlation factor R2, the Pseudo second order model was fitted well with experimental data. The intra particle diffusion model revealed that adsorption in dense membranes was not solely consisting of intra particle diffusion.

关键词： Global warming cellulose acetate Gas adsorption Pseudo order models cO2 Ti O2

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cREVIcE cORROSION BEHAVIOR OF x70 STEEL IN HcO_3^- SOLUTION UNDER cATHODIc POLARIZATION

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Acta Metallurgica Sinica(English Letters) 2008年第4期21卷 235-244页

作者： c.W. Du x.G. Li x. chen P. Liang H. Guo School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Liaoning University of Petroleum and chemical Technology ~shun 113001 China

The crevice corrosion behavior of xTO steel was investigated with a wedge-shaped crevice assembly under -1000 m V （ScE） cathodic polarization in the solutions with various HcO3 concentrations. The potential, current, pH and the oxygen content within the crevice were measured with or without outside coupled specimen. The results indicated that the polarization potential of xTO steel in the crevice dropped with the increase of time under the cathodic polarization. There was a remarkable influence of HcO3 concentration on the potential of xTO steel in the crevice. When HcO3 concentration was up to 0.125%, the surface of the metal was covered with the corrosion products that resulted in the polarization extent of xTO steel decreased. The pH value in the crevice rose and it dropped gradually from the crevice mouth to the bottom under the cathodic polarization. With the increasing of HcO3 concentration, the hydrolyzation reaction of metal in the crevice bottom aggravated. Most of the dissolved oxygen in the crevice was consumed by the cathodic current. The maximum cathodic current on the metal surface was at the crevice mouth and it was much more than that at the crevice bottom.

关键词： cathodic polarization xTO steel Potential pH value Oxygen

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Solar-driven cO_(2) conversion to methane and methanol using different nanostructured cu_(2)O-based catalysts modified with Au nanoparticles

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Journal of Energy chemistry 2024年第4期91卷 287-298页

作者： João Angelo Lima Perini Lilian D.Moura Torquato Juliana Fde Brito Gustavo A.Andolpho Mateus A.Gonçalves Leonardo D.De Angelis Lucas D.Germano Susana I.córdoba de Torresi Teodorico c.Ramalho Maria V.Boldrin Zanoni São Paulo State University(UNESP) Institute of ChemistryRua Prof.Francisco Degni55AraraquaraSP 14800-060Brazil National Institute of Alternative Technologies for Detection Toxicological Evaluation and Removal of Micropollutants and Radioactive Substances(INCT-DATREM)São Paulo State University(UNESP)Institute of ChemistryRua Prof.Francisco Degni55AraraquaraSP 14800-060Brazil Laboratory of Molecular Modelling Department of ChemistryNatural Sciences InstituteFederal University of LavrasLavrasMG 37200-900Brazil Department of chemistry Faculty of ScienceUniversity of Hradec KrálovéHradec Králové50003Czech Republic Instituto de Química Universidade de São PauloAv.Prof.Lineu Prestes 74805508-080São PauloSPBrazil

This work describes the use of TiO_(2)nanotubes-based electrodes(TNT)modified with cu_(2)O nanostructures and gold nanoparticles for the photoelectroreduction of cO_(2)to produce value-added compounds.A thin layer of polydopamine was used as both an adherent agent and an electron transfer mediator,due to itsπ-conjugated electron *** highest production yield was achieved using a TNT@PDA/Nc/Au40%electrode,with Faradaic efficiencies of 47.4%(110.5μM cm^(-2))and 27.8%(50.4μM cm^(-2))for methanol and methane,*** performance of the photoelectrodes was shown to be cu_(2)O facet-dependent,with cubic structures leading to greater conversion of cO_(2)to methanol(43%)and methane(27%),compared to the octahedral morphology,while a higher percentage of metallic gold on the nanostructured cu_(2)O surface was mainly important for *** functional theory(DFT)calculations supported these findings,attributing the superior photoelectrocatalytic performance of the TNT@PDA/Nc/Au40%electrode for cH4generation to the formation of an OcH3intermediate bonded to Au *** using isotope-labeling and analysis by gas chromatograph-mass(Gc-MS)demonstrated that13cO_(2)was the source for photoelectrocatalytic generation of13cH3OH and13cH313cH2OH.

关键词： cu_(2)O nanocubes Photoelectrocatalysis Polydopamine cO_(2) photoelectroreduction DFT calculations

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