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Dynamic respons.s.of two buildings connected by viscoelastic dampers under bidirectional earthquake excitations

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Earthquake Engineering and Engineering Vibration 2014年第1期13卷 137-150页

作者： Z.D. Yang Eddie s.s. Lam Department of Civil and Environmental Engineering The Hong Kong Polytechnic University

In this.s.udy,dynamic respons.s.of two buildings connected by viscoelastic dampers under bidirectional excitations are extensively *** two buildings are a 10-story building and a 16-story building,with the shorter building on the *** dampers are installed at all fl oors of the shorter *** of motion are formulated using a fractional derivative model to represent the viscoelastic *** cas.s.are considered with mass eccentricities at 0,10% and-10% with respect to the dimensions of the *** respons.s.of the buildings are numerically predicted at different damper *** simulation results indicated that the maximum horizontal respons.s.of the buildings without eccentricities are signifi cantly ***,torsional effects are adversely *** asymmetric buildings,the effectiveness of the connecting dampers is affected by building *** a result,mass eccentricities must be taken into account in damper *** compared with vibrations induced by unidirectional excitations,bidirectional excitations can increase the respons.s.of coupled asymmetric *** addition,installing dampers only at the top fl oor of the shorter building may cause a sudden change in lateral stiffness of the taller ***,the story shear envelopes of the taller building are changed.

关键词： bidirectional excitations connecting dampers adjacent buildings fractional derivative

Orderly decorated nanostructural photoelectrodes with uniform spherical TiO2 particles for dye-sensitized solar cells

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Frontiers of Chemical science and Engineering 2015年第4期9卷 532-540页

作者： A.M. Bakhshayesh s.s. Azadfar Department of Research and Development SUN Nanotechnologists Company Tehran 13488-96394 Iran

This.s.udy presents a novel nanostructural electrode made of 20-nm-diameter nanoparticles, which orderly decorated with 2-μm TiO2 particles, deposited by a new gel process. The decorated electrode （DE） is better than the non-decorated electrode （NE） in both light scattering and light harvesting, as confirmed by diffuse reflectance spectroscopy. X-ray diffraction reveals that both electrodes have a mixture of anatase and rutile phas.s. The dye-sensitized solar cell based on the decorated electrode shows the highest power conversion efficiency of 7.80% as a result of less recombination demonstrated by electrochemical impedance spectroscopy. From internal power conversion efficiency measurement, the external quantum efficiency of DE cell at 530 nm is 89%, which is higher than that of NE cell （77%）.

关键词： dye-sensitized solar cell uniform particles,TiO2 gel process light harvesting

Nanocrystallization of α-Fe Crystals in Fe_(52)Cr_(18)Mo_7B_(16)C_4Nb_3 Bulk Amorphous Alloy

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Journal of Materials.s.ience & Technology 2011年第6期27卷 497-502页

作者： s. Ahmadi H.R. shahverdi s.s. saremi Faculty of Engineering Department of Materials Science Tarbiat Modares University

Crystallization kinetics of Fe52Cr18Mo7B16C4Nb3 alloy was evaluated by X-ray diffraction（XRD）,differential scanning calorimetric（DsC） tes.s.and transmission electron microscopy（TEM） observations in this research *** effect,crystallization and growth mechanism were investigated by using DsC tes.s.at four different heating rates（10,20,30,40 K/min）.Results.s.owed that a two-step crystallization process occurred in the alloy in which α-Fe and Fe3B phas.s.were crystallized,respectively in the structure after heat *** energy for the first step of crystallization,i.e.α-Fe was measured to be 421 and 442 kJ/mol according to Kissinger-starink and Ozawa models,***,Avrami exponent calculated from DsC curves was 1.6 and a two-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was observed in the ***,it was known from the TEM observations that crystalline α-Fe phase nucleated in the structure of the alloy in an average size of 10 nm and completely mottled morphology.

关键词： Bulk metallic glass.s.(BMGs) structural amorphous.s.eels (s.s.) Avrami exponent Crystallization and kinetic models

Effects of Nb Alloying on Nano-Crystallization Kinetics of Fe_(55-x)Cr_(18)Mo_7B_(16)C_4Nb_x(x=0, 3) Bulk Amorphous Alloys

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Journal of Materials.s.ience & Technology 2011年第8期27卷 735-740页

作者： s. Ahmadi H.R. shahverdi s.s. saremi Faculty of Engineering Department of Materials Science Tarbiat Modares University

Crystallization kinetics of Fe55-xCrzsMo7B10C4Nbx（x= 0, 3） bulk amorphous alloys were analyzed using X-ray diffraction and differential scanning; calorimetric （DsC） tes.s. In practice, crystallization and growth mechanism were evaluated using DsC tes.s.at four different heating rates （10, 20, 30, and 40 K/rain） and kinetic models. Two-step crystallization behavior was observed when Fe55Cr18MOTB16C4 and Fe52Cr18MoTB16C4Nb3 bulk amorphous alloys were annealed, where Fe36Cr12M010 phase was crystallized in the first step of crystallization. Results.s.ow that Fe36Cr12Mo10 and Fe3C phas.s.were crystallized in the structures of the alloys after further annealing： process. Activation energy for the crystallization of Fe36Cr12Mozo phase was measured to be 543 kJ/mol in Fe52Cr18MoTB16C4Nb3 alloy and 375 kJ/mol for Fe55Cr18Mo7B16C4 alloy according to Kissinger-starink model. Moreover, a two-dimensiona nucleation rate was found in Fe52Cr18Mo7B16C4Nb3 diffusion controlled growth mechanism with decreasing alloy whereas a three-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in crystallization of Fe36Crz2Mo10 phase during annealing of Fe55Cr18MoTB16C4 alloy. TEM （transmission electron microscopy） observations reveal that crystalline Fe36Cr12M010 phase nucleated in the structures of the alloys in an average size of 10 nm with completely mottled morphology.

关键词： Avrami exponent Crystallization Kinetic models Growth mechanisms Bulk amorphous alloys

Experimental investigation into transient pressure puls.s.during pneumatic conveying of fine powders using shannon entropy

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Particuology 2016年第6期14卷 143-153页

作者： Amit Goel Anu Mittal s.s. Mallick Atul sharma Department of Mechanical Engineering Thapar University Patiala Punjab 147004 India

This paper presents the results of an ongoing investigation into transient pressure puls.s.using shan- non entropy. Pressure fluctuations （produced by gas.s.lid two-phase flow during fluidized dense-phase conveying） are recorded by pressure transducers installed at strategic locations along a pipeline. This work validates previous work on identifying the flow mode from pressure signals （Mittal, Mallick, ＆ Wypych, 2014）. Two different powders, namely fly ash （median particle diameter 45 μm, particle den- sity 1950 kg/m3. loosely poured bulk density 950 kg/m3） and cement （median particle diameter 15 p,m, particle density 3060 kg/m3, loosely poured bulk density 1070 kg/m3）, are conveyed through different pipelines （51 mm I.D. × 70 m length and 63 mm I.D. × 24 m length）. The transient nature of pressure fluc- tuations （instead of steady-state behavior） is considered in investigating flow characteristics. shannon entropy is found to increase along straight pipe sections for both solids and both pipelines. However, shannon entropy decreas.s.after a bend. A comparison of shannon entropy among different ranges of superficial air velocity reveals that high shannon entropy corresponds to very low velocities （i.e. 3-5 m/s） and very high velocities （i.e. 11-14 m/s） while low shannon entropy corresponds to mid-range velocities （i.e. 6-8 m/s）.

关键词： Transient pressure fluctuations Fluidized dense phase shannon entropy Flow pattern solid loading ratio superficial air velocity

EFFECT OF sEN DEsIGN ON sURFACE FLUCTUATION AND sOLIDIFYING sHELL IN sLAB MOLD AND ITs OPTIMIZATION

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Acta Metallurgica sinica(English Letters) 2008年第5期21卷 341-350页

作者： D.F. Wu s.s. Cheng school of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

Turbulent flow and heat transfer coupled with solidification in slab continuous casting mold was.s.udied by numerical simulation method. Volume of fluid （VOF） model is used to solve steel-air two-phase flow problem and enthalpy-porosity scheme is introduced to solve the fluid flow problem involving solidification. Contributions of various nozzle port angles and port widths and heights on the free surface fluctuation and the thickness of solidifying shell in slab mold were particularly investigated, based on which the structure of submerged entry nozzle was optimized. Flow inside the common nozzle port cannot fill the entire outlet area, having a recirculation in the upper portion of the port, which is enlarged for the nozzle port with both larger height and width. Results.s.ow that the flow in mold cavity is mainly controlled by the nozzle port angle. The increase of the angle of upper face of the port to shape a roughly streamlined inner-wall improves the effective area fraction of the nozzle, resulting in less jet impingement, weaker free surface turbulence and thicker solidifying steel shell.

关键词： slab continuous casting submerged entry nozzle Optimization Numerical simulation

Ass.s.ment of Diversity, Distribution, Conservation status and Preparation of Management Plan for Medicinal Plants in the Catchment Area of Parbati Hydroelectric Project stage-Ⅲ in Northwestern Himalaya

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Journal of Mountain science 2007年第1期4卷 34-56页

作者： s.s. samant Jitendra s. Butola Aman sharma G.B. Pant Institute of Himalayan Environment and Development Himachal Unit

The developmental activities, particularly the construction of hydroelectric projects are causing a great loss of biodiversity in the Indian Himalayan Region. The Himaehal Pradesh, a part of IHR is well known for the development of hydroelectric projects. The Parbati H.E. Project is amongst the major projects of the state. The different stages of the project are all causing loss of biodiversity of the area. stage Ⅲ of the Parbati H.E. Project is a run of the river scheme on the sainj River downstream of Power House of Parbati H.E. Project stage Ⅱ. The project shall utilize regulated discharge of Parbati H.E. Project stage Ⅱ and inflow of River sainj for power generation, and has been contemplated as a peaking station operating in tandem with stage Ⅱ. The present study has been undertaken to see the impact of hydroelectric project on the biodiversity, particularly on medicinal plants. A total of 104 species of medicinal plants, belonging to different life forms, i.e., trees （23 spp.）, shrubs （22 spp.）, herbs （57 spp.） and ferns （2 spp.） were recorded. The species have been analyzed and studied for their distribution, classification, altitudinal zones, part （s） used, indigenous us.s. nativity, endemism and *** parts of these species, such as whole plants, roots （including rhizomes and tubers）, leaves, flowers, fruits, seeds, stems, barks, spikes, nuts and insect galls are used by the inhabitants for curing various diseas.s.and ailments. 3o species are native to the Himalayan region, 9 species native to the Himalayan region and adjacent countries also and 65 species are non-natives. 9 species are near endemics. Considering the whole Himalaya as a biogeographie unit （sensu lato）, the near endemics are endemic to the Himalaya. Among these species, Zanthoxylum armature is categorized as Endangered and Valeriana wallichii as Vulnerable. Hedychium spicatum, Rhus javanica, Berberis lycium, Thalictrum foliolossum, salvia lanata, Rubia cordifolia and Bergenia ligu

关键词： Hydroelectric project dam submergence area management plan medicinal plant diversity native endemic endangered conservation status indigenous uses Indian Himalaya

Nanomaterials.s.nthes.s.and Effect of Granular Disorders on Electrical Behavior of Lanthanum Manganites

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Journal of Materials.s.ience & Technology 2011年第8期27卷 691-695页

作者： Avneesh Anshul s.s. Amritphale sarabjeet Kaur Renu Hada Advanced Materials & Process.s.Research Institute (CsIR) Hoshangabad Road

Comprehensive investigation on the synthes.s.and electrical transport behaviors of polycrystalline samples of lanthanum manganite due to static disorder was reported. The process parameters were optimized for different batches to yield variable grain sizes. Different sintering conditions and technique like thermal cycling were employed to obtain better grain packing density. The liquid nitrogen and air quenching of the samples were carried out to restrict the grain growth with well defused grain boundary. Variable grain habits and sizes were synthesized by standard solid-state reaction and modified sol-gel synthes.s.routes. Large variation of grain size, connectivity and packing was observed by varying sintering temperature and synthes.s.technique. The process dependent grain sizes were observed in the wide range from 20 nm to 1.5 μm by transmission and scanning electron microscopy, The variations in residual res.s.ivity as well as metal-insulator transitions are observed. The observed data were analyzed on the bas.s.of contributions from various dynamic interactions and static disorders.

关键词： Order-disorder effect sintering Manganites

Numerical simulation of fluidized dense-phase pneumatic conveying of powders to develop improved model for solids friction factor

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Particuology 2017年第6期15卷 42-50页

作者： Baldeep Kaur Anu Mittal s.s. Mallick Renhu Pan soumendu Jana school of Physics and Materials.s.ience Thapar University Patiala Punjab 147004 India Department of Mechanical Engineering Thapar University Patiala Punjab 147004 India Fujian Longking Co. Ltd. Longyan Fujian 364000 China

Accurate prediction of the solids friction factor through horizontal straight pipes is important for the reliable design of a pneumatic conveying s.s.em, but it is a challenging assignment to date because of the highly concentrated, turbulent, and complex nature of the gas.s.lids mixture. Power-station fly ash was transported through different pipeline configurations. Numerical simulation of the dense-phase pneumatic conveying s.s.ems for three different solids and two different air flow rates have shown that particle and actual gas velocities and the ratio of the two velocities increas.s.in the flow direction, whereas the reverse trend was found to occur for the solids volumetric concentration. To develop a solids friction-factor model suitable for dense-phase flow, we modified an existing pure dilute-phase model by incorporating sub-models for particle and actual gas velocities and impact and solids friction factor. The solids friction-factor model was validated by using it for scale-up predictions for total pipeline pressure drops in longer and larger pipes and by comparing experimental and predicted pneumatic conveying characteristics for different solids flow rates. The accuracy of the prediction was compared with a recently developed two-layer-based model. We discussed the effect of incorporating the particle and actual gas velocity terms in the solids friction-factor model instead of superficial air velocity.

关键词： Pneumatic conveying Dense-phase Numerical analysis Pressure drop scale-up validation