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Exploring the mechanical properties of steel-and polypropylene-reinforced ultra-high-performance concrete through numerical analyses and experimental multi-target digital image correlation

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Frontiers of Structural and Civil Engineering 2023年第8期17卷 1228-1248页

作者： Behrooz DADMAND hamed SADAGHIAN Sahand KHALILZADEHTABRIZI Masoud POURBABA amir MIRMIRAN Department of Civil Engineering University of RaziKermanshah ***Iran Department of Civil Engineering University of TabrizTabriz ***Iran Ingram School of Engineering Texas State UniversitySan MarcosTX 78666USA University of Texas at Tyler TylerTX 75799USA

This study presents experimental and numerical investigations on the mechanical properties of ultrahigh-performance concrete(UHPC)reinforced with single and hybrid micro-and macro-steel and polypropylene *** this purpose,a series of cubic,cylindrical,dog-bone,and prismatic beam specimens(total fiber by volume=1%,and 2%)were tested under compressive,tensile,and flexural loadings.A method,namely multi-target digital image correlation(MT-DIC)was used to monitor the displacement and deflection *** obtained experimental data were subsequently used to discuss influential parameters,i.e.,flexural strength,tensile strength,size effect,*** analyses were also carried out using finite element software to account for the sensitivity of different ***,nonlinear regression analyses were conducted to obtain the flexural load-deflection *** results showed that the MT-DIC method was capable of estimating the tensile and flexural responses as well as the location of the crack with high *** addition,the regression analyses showed excellent consistency with the experimental results,with correlation coefficients close to ***,size-effect modeling revealed that modified Bazant theory yielded the best estimation of the size-effect phenomenon compared to other models.

关键词： UHPC MT-DIC flexural behavior tensile behavior steel fiber polypropylene fiber

Towards digital architecture,engineering,and construction(AEC)industry through virtual design and construction(VDC)and digital twin

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Energy and Built Environment 2023年第2期4卷 169-178页

作者： hamed Nabizadeh Rafsanjani amir Hossein Nabizadeh School of Engineering and Applied Sciences Western Kentucky UniversityBowling GreenKY 42101United States Kerman University of Medical science KermanIran/INESC-ID/ISTUniversity of LisbonLisbon 1000-029Portugal

The architecture,engineering,and construction(AEC)industry is undergoing a substantial change,and the tech-nological advancements are shaping the future of this *** years,numerous tools have been developed based on building information modeling(BIM)and the Internet of Things(IoT)to manage a variety of tasks and activities within different construction and operational phases in the AEC ***,with the advent of novel internet-enabled technologies in providing the ability of real-time connectivity,researchers have started to develop virtual design and construction(VDC)and digital twin approaches to remotely monitor,control,and optimize different work progresses and activities in real-time at any work level in the AEC *** paper presents a reference model to illustrates the main advantages and applications of VDC and digital twin,and to demonstrate their trends and anticipated cost savings in the AEC industry at a global *** technological advancements along with augmented reality(AR)and virtual reality(VR)can offer the unique benefit of real-time monitoring of the current status as well as predicting the future of any physical structure at any level of *** global demand and usage of these technological advancements will lead to great cost savings in the AEC industry which would be US$950 million in design and construction and US$400 million in operation and maintenance phases in the non-residential AEC industry in *** paper also discusses the future challenges of VDC and digital twin in the *** a main line of future research,these technologies can simultaneously be utilized with artificial intelligence to enable human-centered decision making to automate and optimize work *** integrations of VDC,digital twin,artificial intelligence,and human-centered approaches will shape the future of the AEC industry and provide numerous research opportunities in this domain.

关键词： Virtual design and construction Digital twin BIM IoT Artificial intelligence Augmented reality Virtual reality AEC industry

Quantifying cardinal temperatures and thermal time required for germination of Silybum marianum seed

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The Crop Journal 2015年第2期3卷 145-151页

作者： Ghasem Parmoon Seyed amir Moosavi hamed Akbari Ali Ebadi Department of Agronomy and Plant Breeding Faculty of Agriculture Mohaghegh Ardabili University Department of Agronomy Faculty of Agriculture Tarbiat Modares University

The response of seed germination to environmental factors can be estimated by nonlinear regression. The present study was performed to compare four nonlinear regression models(segmented, beta, beta modified, and dent-like) to describe the germination rate–temperature relationships of milk thistle(Silybum marianum L.) at six constant temperatures, with the aim of identifying the cardinal temperatures and thermal times required to reach different germination percentiles. Models and statistical indices were calibrated using an iterative optimization method and their performance was compared by root mean square error(RMSE), coefficient of determination(R2) and Akaike information criterion correction(AICc). The beta model was found to be the best model for predicting the required time to reach 50% germination(D50),(R2= 0.99;RMSE = 0.004; AICc =-276.97). Based on the model outputs, the base, optimum, and maximum temperatures of seed germination were 5.19 ± 0.79, 24.01 ± 0.11, and 34.32 ± 0.36 °C,respectively. The thermal times required for 50% and 90% germination were 4.99 and7.38 degree-days, respectively.

关键词： Silymarin Regression models Cardinal temperatures Seed germination

Case study of hydraulic fracturing in an offshore carbonate oil reservoir

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Petroleum Research 2022年第4期7卷 419-429页

作者： Mohammad Azad Mojtaba Ghaedi amir Farasat Hadi Parvizi hamed Aghaei Department of Petroleum Engineering School of Chemical and Petroleum EngineeringShiraz UniversityIran Iranian Offshore Oil Company TehranIran Petroxin Ltd LondonUnited Kingdom

Maximizing petroleum production while efficiently managing the operational costs is the oil and gas industry's primary goal which requires innovative engineering approaches and production-enhancing treatments such as hydraulic fracturing(HF).During the HF process,the injected fluid mixed with sands or proppants will create permanent fluid channels to drain more of the reservoir *** level of complexity and various constraints involved in real field treatments have made HF even more chal-lenging in layered carbonate reservoirs with the water drive mechanism.A prominent concern is the downward fracture growth to the oil/water contact zone that may cause unfavorable water cut *** fracture height confinement criterion necessitates optimization of fracture dimension *** height development is mainly a function of in-situ stress conditions and stress magnitude differences between geologic *** cases with a water table at the proximity of the wellbore,fracture height directly affects the operational *** paper demonstrates a practical step-by-step approach towards the design of hydraulic fracturing treatment in an offshore carbonate oil *** modeling process involves optimization of the location,number,and conductivity of the proposed ***-jection of high viscosity fluid causes a bi-wing vertical planar fracture to propagate perpendicular to the direction of minimum horizontal stress in the strike-slip faulting *** of the induced hydraulic fractures are also impacted by the amount and type of ***,as with this case study,the magnitude of vertical stress is in the same range as the maximum horizontal stress;the fracture height growth is the limiting *** LGR method is used to define fractures in the dynamic reservoir model which has been built based on a complete set of data ranging from the analyses of logs,core samples,and seismic details,to perform production forecasts and economic ev

关键词： Hydraulic fracture design Carbonate reservoirs Proppant selection Economic analysis Reservoir modeling

Antioxidant therapy in the management of acute,chronic and post-ERCP pancreatitis:A systematic review

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World Journal of Gastroenterology 2009年第36期15卷 4481-4490页

作者： Seyed Sajad Mohseni Salehi Monfared hamed Vahidi amir Hossein Abdolghaffari Shekoufeh Nikfar Mohammad Abdollahi Endocrinology and Metabolism Research Centre Tehran University of Medical Sciences Student Scientific Research Center Tehran University of Medical Science Pharmaceutical Sciences Research Center Tehran University of Medical Sciences Food&Drug Affairs and Food&Drug Laboratory Research Center Ministry of Health&Medical Education Faculty of Pharmacy and Pharmaceutical Sciences Research Center and Endocrinology&Metabolism Research CentreTehran University of Medical Sciences

We systematically reviewed the clinical trials which recruited antioxidants in the therapy of pancreatitis and evaluated whether antioxidants improve the outcome of patients with pancreatitis. Electronic bibliographic databases were searched for any studies which investigated the use of antioxidants in the management of acute pancreatitis （AP） or chronic pancreatitis （CP） and in the prevention of post-endoscopic retrograde cholangio-pancreatography （post-ERCP） pancreatitis （PEP） up to February 2009. Twenty-two randomized, placebo-controlled, clinical trials met our criteria and were included in the review. Except for a cocktail of antioxidants which showed improvement in outcomes in three different clinical trials, the results of the administration of other antioxidants in both AP and CP clinical trials were incongruent and ***, antioxidant therapy including allopurinol and N-acetylcysteine failed to prevent the onset of PEP in almost all trials. In conclusion, the present data do not support a benefit of antioxidant therapy alone or in combination with conventional therapy in the management of AP, CP or PER Further double blind, randomized, placebo-controlled clinical trials with large sample size need to be conducted.

关键词： Antioxidant Post-endoscopic retrogradecholangio-pancreatography pancreatitis Oxidative stress,Therapy Acute pancreatitis Chronic pancreatitis

Effect of single roll drive rolling on microstructure， texture， and tensile anisotropy of Al-5.6Zn-2.5Mg-1.4Cu aluminum alloy

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Transactions of Nonferrous Metals Society of China 2022年

作者： amir Kazemi-Navaee Roohollah Jamaati hamed Jamshidi Aval Department of Materials Engineering， Babol Noshirvani University of Technology

The current research aims to study the microstructure and texture development during single roll drive rolling (SRDR) of the Al-5.6Zn-2.5Mg-1.4Cu alloy. The relationship between anisotropy with microstructure and texture was investigated in detail. The SRDR process was immediately performed on the solution-treated sample with four different thickness reductions of 10， 20， 40， and 60%. Microstructural examination by optical and scanning electron microscopes， texture by X-ray diffraction， and tensile properties were conducted. The results showed that the value of in-plane anisotropy was significantly reduced from 11.6% in solution-treated alloy to 2.4% and 3.1% in 40% and 60% rolled samples， respectively. This was due to the formation of the Rotated Cube component， decreasing the overall texture intensity， and the formation of new grains through dynamic recrystallization. The yield strength in the rolling direction (RD) was higher than the value for the transverse direction (TD) which was due to grain morphology and texture in these samples. The severity of Portevin–Le Chatelier (PLC) along the RD (0°) was much lower than along the HD (45°) and TD (90°) directions owing to the presence of several strong orientations along the RD. By increasing the thickness reduction， the difference between strain hardening rate of RD， HD， and TD decreased due to the decrement of texture intensity. There was no difference between the fracture surfaces of 60% samples in the RD， HD， and TD， revealing nearly isotropic fracture behavior.

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单辊驱动轧制对Al-5.6Zn-2.5Mg-1.4Cu铝合金显微组织、织构和力学性能各向异性的影响

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Transactions of Nonferrous Metals Society of China 2023年第11期33卷 3266-3281页

作者： amir KAZEMI-NAVAEE Roohollah JAMAATI hamed JAMSHIDI AVAL Department of Materials Engineering Babol Noshirvani University of TechnologyShariati Ave.Babol 47148–71167Iran

研究在单辊驱动轧制Al-5.6Zn-2.5Mg-1.4Cu合金过程中,材料显微组织和织构的变化,并详细研究其力学性能各向异性与显微组织和织构的关系。对样品固溶处理后立即进行单辊驱动轧制,厚度减薄率分别为10%、20%、40%和60%。通过光学和扫描电... 详细信息

研究在单辊驱动轧制Al-5.6Zn-2.5Mg-1.4Cu合金过程中,材料显微组织和织构的变化,并详细研究其力学性能各向异性与显微组织和织构的关系。对样品固溶处理后立即进行单辊驱动轧制,厚度减薄率分别为10%、20%、40%和60%。通过光学和扫描电子显微镜对显微组织进行表征,通过X射线衍射仪对织构进行表征,并对拉伸力学性能进行分析。结果表明,减薄率为40%和60%的轧制样品,其面内各向异性值从固溶处理合金的11.6%分别显著降低到2.4%和3.1%。这是由于旋转立方织构的形成减小了总的织构强度以及动态再结晶过程中新晶粒的形成。由于样品中晶粒形貌和织构不同,样品轧制方向(RD)比横向(TD)的屈服强度高。沿RD存在的几个较强取向导致沿RD(0°)的Portevin–LeChatelier(PLC)效应明显低于沿HD(45°)和TD(90°)的。随着厚度减薄率的增大,织构强度减小,导致RD、HD和TD之间的应变硬化率差异减小。而对于减薄率为60%的样品,其RD、HD和TD的断裂面无差异,说明其断裂行为为各向同性。

关键词： AA7075铝合金单辊驱动轧制织构力学性能各向异性

Physical characteristics modification of a SiGe-HBT semiconductor device for performance improvement in a terahertz detecting system

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Journal of Semiconductors 2015年第5期36卷 61-65页

作者： hamed Ghodsi Hassan Kaatuzian Photonics Research Laboratory(P.R.L.) Electrical Engineering DepartmentAmir Kabir University of Technology

In order to improve the performance of a pre-designed direct conversion terahertz detector which is implemented in a 0.25 μm-SiGe-BiCMOS process, we propose some slight modifications in the bipolar section of the SiGe device physical design. Comparison of our new proposed device and the previously reported device is done by SILVACO TCAD software simulation and we have used previous experimentally reported data to confirm our software simulations. Our proposed modifications in device structural design show a present device responsivity improvement of about 10% from 1 to 1.1 A/W while the bandwidth improvement is about 218 GHz. The minimum noise equivalent power at detector output is increased by about 14.3% and finally power consumption per pixel at the maximum responsivity is decreased by about 5%.

关键词： terahertz SiGe HBT physical structure direct conversion detector

未开发远景区页岩气的综合评价方法--以伊朗卢雷斯坦页岩气区为例

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石油勘探与开发 2022年第3期49卷 522-529页

作者： ABDOLLAHI Reza MOTAHHARI Seyed Mahdia ASKARI amir Abbas HEMATPUR hamed ZAMANI Ziba TIRTASHI Rahim Bagheri DARYABANDEH Manouchehr 陈浩伊朗德黑兰石油工业研究所EOR研究部德黑兰***伊朗伊朗德黑兰石油工业研究所地球科学部德黑兰***伊朗伊朗国家石油公司勘探局地球化学部德黑兰***伊朗中国石油大学(北京)安全与海洋工程学院北京102249

页岩气评价方法及关键参数研究表明,仅靠技术指标来寻找地质甜点并不能实现页岩气的商业经济开发。通过将总有机碳含量、镜质体反射率等技术指标与内部收益率、投资回收期等经济指标相结合,提出一套经济指标和技术指标相结合的研究方法... 详细信息

页岩气评价方法及关键参数研究表明,仅靠技术指标来寻找地质甜点并不能实现页岩气的商业经济开发。通过将总有机碳含量、镜质体反射率等技术指标与内部收益率、投资回收期等经济指标相结合,提出一套经济指标和技术指标相结合的研究方法,用以筛选页岩气未开发区的最佳技术经济开发甜点。采用该方法通过总有机碳含量、镜质体反射率、有效储集层厚度和含气量等参数筛选21个地质甜点。再基于类比研究法,以压力梯度、黏土矿物含量、埋藏深度等参数为类比依据,选择Eagle Ford页岩为类比对象,提取采收率和生产曲线两项指标,估算研究区的技术可采储量。在此基础上,结合内部收益率、投资回收期等经济指标评价地质甜点的经济性。应用这套多参数综合评价方法,对伊朗卢雷斯坦地区白垩系页岩气储集层S_(1)层和S_(2)层进行评估,确定该区域的最佳技术经济开发甜点。结果表明,在净现值取其P_(10)值(累计概率10%时对应的参数值)的情况下,技术可采储量和经济可采储量总量分别为7875×10^(8)m^(3)和4306×10^(8)m^(3),有11个地质甜点具有商业开发价值,其中1号甜点价值最高,净现值为35×10^(8)美元。

关键词：页岩气地质甜点技术经济开发甜点页岩气经济评价伊朗卢雷斯坦地区白垩系