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Frontiers of Structural and Civil Engineering 2020年第1期14卷 169-184页

作者： Elmira SHOUSHTARI MSaiid SAIIDI ahmad itani Mohamed AMOUSTAFA Department of Civil and Environmental Engineering University of NevadaReno NV 89557USA

This paper presents pretest analysis of a shake table test model of a 0.35-scale,two-span,steel plate girder bridge.The objective of pretest analysis was to obtain an insight on the seismic response of the bridge model during the shake table tests.The bridge included seat type abutments,full-depth precast deck panels,and a two-column bent in which columns were pinned to the footing and integral with superstructure.Six accelerated bridge construction connections were incorporated in the bridge model.An analytical model was developed in OpenSees and was subjected to ten input bi-directional earthquake motions including near-fault and far-field records.The overall seismic response of the bridge was satisfactory for all the earthquake records at 100%,150%,and 200%design level.All connections and capacity-protected components remained elastic,and the average ductility capacity surpassed the ductility demand even at 200%design level.Using experimental fragility curves developed for RC bridge columns,it was predicted that there was a probability of 45%that columns would undergo the imminent failure in the last run and a probability of 30%for their failure.

关键词： shake table test accelerated bridge construction steel girder bridge OpenSEES UHPC simple for dead continuous for live

Influence of earthquake ground motion incoherency on multi-support structures

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Earthquake Engineering and Engineering Vibration 2002年第2期1卷 167-180页

作者：杨庆山 M.Saiid Saiidi 王航 ahmad itani School of Civil Engineering and Architecture Northern Jiaotong University.Beijing.100044.China. Department of Civil Engineering University of NevadaRenoNV89557USA Beijing General Municipal Engineering Design and Research Institute.China Department of Civil Engineering University of Nevada.RenoNV.89557USA

A linear response history analysis method is used to determine the influence of three factors:geometric incoherency,wave-passage,and local site characteristics on the response of lnulti-support structures subjected to differential ground motions.A one-span frame and a reduced model of a 24-span bridge,located in Las Vegas,Nevada are studied,in which the influence of each of the three factors and their combinations are analyzed.It is revealed that the incoherency of earthquake ground motion can have a dramatic influence on structural response by modifying the dynamics response to uniform excitation and inducing pseudo-static response,which does not exist in structures subjected to uniform excitation.The total response when all three sources of ground motion incoherency are included is generally larger than that of uniform excitation.

关键词： earthquake bridges ground motion incoherency wave passage local site characteristics multi-support structures

Finite element investigation of steel built-up shear links subjected to inelastic deformations

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Earthquake Engineering and Engineering Vibration 2004年第2期3卷 195-203页

作者： Peter Dusicka ahmad M.itani Ian G.Buckle Department of Civil and Environmental Engineering Portland State UniversityP O.Box 751PortlandOregon97207USA Assistant Professor Department of Civil Engineering Mail Stop 258University of NevadaRenoNevada89557USA Associate Professor Department of Civil Engineering Mail Stop 258University of NevadaRenoNevada89557USA Professor

Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.

关键词： finite element investigation steel built-up shear link inelastic deformation

Response of a 2-story test-bed structure for the seismic evaluation of nonstructural systems

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Earthquake Engineering and Engineering Vibration 2016年第1期15卷 19-29页

作者： Siavash Soroushian E. “Manos” Maragakis Arash E. Zaghi Esmaeel Rahmanishamsi ahmad M. itani Gokhan Pekcan Advanced Technology and Research Arup.560 Mission Street 7th Floor San Francisco CA 94105 USA Department of Civil and Environmental Engineering University of Nevada Reno 89557 NV USA Department of Civil and Environmental Engineering University of Connecticut Storrs 06269-3037 CT USA

A full-scale, two-story, two-by-one bay, steel braced-frame was subjected to a number of unidirectional ground motions using three shake tables at the UNR-NEES site. The test-bed frame was designed to study the seismic performance of nonstructural systems including steel-framed gypsum partition walls, suspended ceilings and fire sprinkler systems. The frame can be configured to perform as an elastic or inelastic system to generate large floor accelerations or large inter story drift, respectively. In this study, the dynamic performance of the linear and nonlinear test-beds was comprehensively studied. The seismic performance of nonstructural systems installed in the linear and nonlinear test-beds were assessed during extreme excitations. In addition, the dynamic interactions of the test-bed and installed nonstructural systems are investigated.

关键词： seismic design steel braced frame building shake table simulation full scale experiment nonstructuralsystems

Design multifunctional Mg–Zr coatings regulating Mg alloy bioabsorption

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Journal of Magnesium and Alloys 2024年第4期12卷 1461-1478页

作者： Zohra Benzarti Sandesh itani JoséDavid Castro Sandra Carvalho Ana Sofia Ramos University of Coimbra CEMMPREARISEDepartment of Mechanical EngineeringRua Luís Reis Santos3030-788CoimbraPortugal Laboratory of Multifunctional Materials and Applications(LaMMA) Department of PhysicsFaculty of Sciences of SfaxUniversity of SfaxSoukra Road km 3.5B.P.1171Sfax3000Tunisia

Magnesium(Mg)alloys are widely used for temporary bone implants due to their favorable biodegradability,cytocompatibility,hemocompatibility,and close mechanical properties to bone.However,rapid degradation and inadequate strength limit their applicability.To overcome this,the direct current magnetron sputtering technique is employed for surface coating in Mg-based alloys using various zirconium(Zr)content.This approach presents a promising strategy for simultaneously improving corrosion resistance,maintaining biocompatibility,and enhancing strength without compromising osseointegration.By leveraging Mg’s inherent biodegradability,it has the potential to minimize the need for secondary surgeries,thereby reducing costs and resources.This paper is a systematic study aimed at understanding the corrosion mechanisms of Mg–Zr coatings,denoted Mg-xZr(x=0–5 at.%).Zr-doped coatings exhibited columnar growth leading to denser and refined structures with increasing Zr content.XRD analysis confirmed the presence of the Mg(00.2)basal plane,shifting towards higher angles(1.15°)with 5 at.%Zr doping due to lattice parameter changes(i.e.,decrease and increase of“c”and“a”lattice parameters,respectively).Mg–Zr coatings exhibited“liquidphilic”behavior,while Young’s modulus retained a steady value around 80 GPa across all samples.However,the hardness has significantly improved across all samples’coating,reaching the highest value of(2.2±0.3)GPa for 5 at.%Zr.Electrochemical testing in simulated body fluid(SBF)at 37℃ revealed a significant enhancement in corrosion resistance for Mg–Zr coatings containing 1.0–3.4 at.%Zr.Compared with the 5 at.%Zr coating which exhibited a corrosion rate of 32 mm/year,these coatings displayed lower corrosion rates,ranging from 1 to 12 mm/year.This synergistic enhancement in mechanical properties and corrosion resistance,achieved with 2.0–3.4 at.%Zr,suggests potential ability for reducing stress shielding and controlled degradation performance,and consequently,promising functional biodegradable materials f

关键词： Mg-Zr coatings Magnetron sputtering Nanoindentation Corrosion resistance Bone implants

Laboratory diagnosis of nonpolio enteroviruses:A review of the current literature

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Biosafety and Health 2023年第2期5卷 112-119页

作者： Tarek itani Vladislav Chalapa Aleksandr Semenov Aleksandr Sergeev Yekaterinburg Research Institute of Viral Infections SRC VB VEKTORRospotrebnadzorYekaterinburgRussia Ural State Medical University YekaterinburgRussia

Infections by nonpolio enteroviruses(EVs)are highly prevalent,particularly among children and neonates,where they may cause substantial morbidity and mortality.Laboratory diagnosis of these viral infections is important in patient prognosis and guidance of clinical management.Although the laboratory diagnosis of non-polio EVs is mainly based on molecular techniques,classical virus-isolation techniques are still used in refer-ence laboratories.Other techniques,such as antigen detection and serology,are becoming obsolete and rarely used in diagnosis.An important part of diagnosis and surveillance of EV infections is viral typing by VP1 gene sequencing using conventional Sanger technique and more recently,full-genome next-generation sequencing.The latter allows the typing of all EVs,better investigation of EV outbreaks,detection of coinfec-tion,and identification of severity markers in the EV genome.

关键词： Nonpolio enteroviruses Virus isolation Nucleic acid amplification tests Sanger sequencing Next-generation sequencing

Model tests and corresponding numerical simulations on cave model subjected to thermo-mechanical loading

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Underground Space 2022年第2期7卷 162-183页

作者： Peng Peng Hiromasa Iwai Eishi Ohne Yusuke itani Feng Zhang Department of Civil Engineering Nagoya Institute of TechnologyShowa-kuGokiso-choNagoya 466-8555Japan

Geological repository of high-level nuclear waste(HLNW),the most feasible approach for the safe and permanent treatment of HLNW without human intervention,has been investigated for years by many researchers.In some countries,real facilities for the geo-logical repository are already under construction.In Japan,however,due to complicated geologic conditions,especially underground water and fractured rock masses,and the high risk of natural disasters,ensuring the long-term stability of the method remains a struggle.The influential factors include underground water,heat generation from radioactive waste,and thermal and chemical weathering of the surrounding rock mass as a natural barrier.It is difficult to estimate and verify the long-term stability for up to one hundred thousand years,a complicated thermal-hydraulic-mechanical-chemical coupling behavior,via any field test.The objective of the study is to develop a numerical method for predicting the long-term stability of geological repositories.As the first step toward realizing this objec-tive,heating and loading tests on cave model made of man-made rock specimens that are composed of diatoms,gypsum,and water,which are viscoplastic materials,were conducted,based on which a newly proposed numerical method with finite element method(FEM)was used to describe the thermal,mechanical,and time-dependent behavior of the model tests for a geological repository.To ensure the accuracy of the numerical calculations,all the material parameters in the thermoelasto-viscoplastic model with consideration of overconsolidation,the structure,and the influence of intermediate stress were determined via triaxial compression/creep tests under various temperatures,confining stresses,and loading rates.Finally,the validity of the numerical method was demonstrated by model tests over a limited time span.

关键词： Geological repository High-level nuclear waste Heating and loading test Cave model Thermoelasto-viscoplasticity FEM Long-term stability

Model-based adaptive controller for personalized ventilation and thermal comfort in naturally ventilated spaces

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Building Simulation 2021年第6期14卷 1757-1771页

作者： Dalia Ghaddar Mariam itani Nesreen Ghaddar Kamel Ghali Joseph Zeaiter Mechanical Engineering Department American University of BeirutP.O.Box 11-0236Beirut 1107-2020Lebanon Mechanical Engineering Department Phoenicia UniversityDistrict of ZahraniLebanon Bahaa and Walid Bassotne Department of Chemical Engineering and Advanced Energy American University of BeirutBeirutLebanon

This work develops a standalone autonomously controlled personalized ventilation(PV)unit in a naturally ventilated(NV)office space to maintain acceptable thermal comfort{TQ under steady and transient indoor conditions and activity levels.The NV-PV proportional integral derivative(PID)controller adjusts the PV supply temperature(7spv)at the occupant set flow rate(Qspv)based on predicted TC using a regression model.The target TC level that the controller attains at all times is between 0(neutral)and 1(slightly comfortable).Process transfer functions were developed and then used to find the adaptive PID tuning coefficients using the Internal Model Control(IMC)method.The controller was tested in a case study at indoor temperature range of 25 to 33℃ with relative humidity range of 55%and 80%.It was shown that the NV-PV controller adjusted Tspv to maintain acceptable TC under transients of indoor conditions and metabolic rates.

关键词： adaptive PID controller personalized ventilation natural ventilation thermal comfort

Thermo-elasto-viscoplastic mechanical behavior of manmade rock and its numerical modeling

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Underground Space 2019年第2期4卷 121-132页

作者： Feng Zhang Yong-lin Xiong Yusuke itani Eishi One Dept.of Civil Engineering Nagoya Institute of TechnologyNagoya 466-8555Japan Institute of Geotechnical Engineering Ningbo UniversityNingbo 315211China JR East Japan Consultants Co.Ltd. Tokyo 141-0003Japan

In this study,a thermo-elasto-viscoplastic model for soft rock is proposed to describe its fundamental mechanical behavior of soft rock such as the influences of overconsolidation,intermediate principal stress,temperature,time dependency and inherent structure with a unified set of parameters.In the model,the concepts of subloading and superloading yielding surfaces are introduced to describe the influence of overconsolidation and structure on the deformation and strength of soft rock.The influence of the intermediate principal stress is also properly considered by adopting a transformed stress tensor t_(ij).To consider the temperature effect,a thermo-induced equivalent stress is introduced to consider its influence on the yielding surfaces,the evolution of the overconsolidation,and the structure when subjected to shearing loading under different conditions.By comparing the calculated results with test results of a manmade rock under different loading and temperature conditions,the availability and accuracy of the proposed model are carefully investigated,and the performance of the proposed model is verified in detail.

关键词： Manmade soft rock Thermo-elasto-viscoplasticity Critical state Overconsolidation Structure

Autoimmune pancreatitis complicated by gastric varices:A report of 3 cases

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World Journal of Gastroenterology 2012年第31期18卷 4228-4232页

作者： Norihiro Goto Jun Mimura Toshinao itani Motohito Hayashi Yukari Shimada Tomoaki Matsumori Department of Gastroenterology Nishi-Kobe Medical CenterHyogo 651-2273Japan

We present three cases of autoimmune pancreatitis(AIP) complicated by gastric varices.Case 1:A 57-yearold man was diagnosed with AIP complicated by gastric varices and splenic vein obstruction.Splenomegaly was not detected at the time of the diagnosis.The AIP improved using steroid therapy,the splenic vein was reperfused,and the gastric varices disappeared;case 2:A 55-year-old man was diagnosed with AIP complicated by gastric varices,splenic vein obstruction,and splenomegaly.Although the AIP improved using steroid therapy,the gastric varices and splenic vein obstruction did not resolve;case 3:A 68-year-old man was diagnosed with AIP complicated by gastric varices,splenic vein obstruction,and splenomegaly.The gastric varices,splenic vein obstruction,and AIP did not improve using steroid therapy.These three cases suggest that gastric varices or splenic vein obstruction without splenomegaly may be an indication for steroid therapy in patients with AIP because the complications will likely become irreversible over time.

关键词：静脉曲张自身免疫性胰腺炎合并胃脾肿大 AIP 类固醇