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Using an Inhibitor to Prevent Plasticizer Migration from Polyurethane Matrix to EPDM Based Substrate

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Chinese Journal of Polymer Science 2019年第7期37卷 681-686页

作者： hadi Rezaei-Vahidian Tohid Farajpour Mahdi Abdollahi Space Transportation Research Institute Iranian Space Research CenterTehranIran Polymer Reaction Engineering Department Faculty of Chemical EngineeringTarbiat Modares UniversityTehranIran

The loss of adhesion between the propellant and insulator is one of the most important problems in solid propellant motors due to migration of plasticizer to interface of propellant and insulator. In this work, the polyurethane (PU) binder containing DOP plasticizer was used as a polymeric matrix and β-cyclodextrin (β-CD) was applied as inhibitor agent to prevent plasticizer migration from the PU matrix into the ethylene propylene diene monomer (EPDM) substrate. To increase the compatibility of β-CD and PU matrix, a derivative of β-CD has been synthesized using toluene diisocyanate (β-CD-TDI). The synthesized derivative was characterized by MALDI-MS and FTIR-ATR analyses. FTIR-ATR results confirmed the formation of bonding between β-CD and the polymeric network while the MALDIMS results showed that the synthesized derivative contained two β-CD and 7 TDI molecules bonded to β-CD. Investigation of the mechanical properties of PU modified by β-CD-TDI showed a decrease in tensile strength and an increase in elongation at break with increasing β-CD-TDI content. DMTA results showed a decrement in crosslinking density by increasing the β-CD-TDI content. Also, to investigate plasticizer migration, extraction of the DOP plasticizer from samples was performed using dichloromethane solvent and its concentration was measured by gas chromatography. The results of migration evaluation after four months showed that using β-CD as an inhibitor agent in the PU binder could prevent the migration of plasticizer to EPDM substrate.

关键词： Plasticizer migration β-Cyclodextrin Polyurethane

Energy Efficient Scheduler of Aperiodic Jobs for Real-time Embedded Systems

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International Journal of Automation and computing 2020年第5期17卷 733-743页

作者： Hussein El Ghor El-hadi MAggoune University Institute of Technology Lebanese UniversityLebanon Sensor Networks and Cellular Systems(SNCS)Research Center UTSaudi Arabia Electrical Engineering Department University of Tabuk Sensor Networks and Cellular Systems(SNCS)Research Center 71491 TabukSaudi Arabia

Energy consumption has become a key metric for evaluating how good an embedded system is,alongside more performance metrics like respecting operation deadlines and speed of *** improvement is no longer the only metric by which optimality is *** fact,energy efficiency is becoming a preferred choice with a fundamental objective to optimize the system's *** this work,we propose an optimal energy efficient scheduling algorithm for aperiodic real-time jobs to reduce CPU energy ***,we apply the concept of real-time process scheduling to a dynamic voltage and frequency scaling(DVFS)*** address a variant of earliest deadline first(EDF)scheduling algorithm called energy saving-dynamic voltage and frequency scaling(ES-DVFS)algorithm that is suited to unpredictable future energy production and irregular job *** prove that ES-DVFS cannot attain a total value greater than C/ˆSα,whereˆS is the minimum speed of any job and C is the available energy *** also investigate the implications of having in advance,information about the largest job size and the minimum speed used for the competitive factor of *** show that such advance knowledge makes possible the design of semi-on-line algorithm,ES-DVFS∗∗,that achieved a constant competitive factor of 0.5 which is proved as an optimal competitive *** experimental study demonstrates that substantial energy savings and highest percentage of feasible job sets can be obtained through our solution that combines EDF and DVFS optimally under the given aperiodic jobs and energy models.

关键词： Real-time systems energy efficiency aperiodic jobs scheduling dynamic voltage scaling low-power systems embedded systems

Optimal control homotopy perturbation method for cancer model

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International Journal of Biomathematics 2019年第3期12卷 79-90页

作者： Malihe Najafi hadi Basirzadeh Department of Mathematics Faculty of Mathematical Sciences and Computer Shahid Chamran University of Ahvaz Ahvaz Iran

In this paper, we introduced the optimal control homotopy perturbation method (OCHPM) by using the homotopy perturbation method (HPM). Every one, by using of the proposed method, can obtain numerical solutions of mathematical modeling for cancer-immunotherapy. In this paper, in order to prove the preciseness and efficiency of the OCHPM method, we compared the obtained numerical solutions with HPM. The results obtained showed that the OCHPM method is powerful to generate the numerical solutions for some therapeutic models.

关键词： Optimal control homotopy perturbation method cancer immunotherapy epidemic models

A robust subband adaptive filter algorithm for sparse and block-sparse systems identification

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Journal of Systems Engineering and Electronics 2021年第2期32卷 487-497页

作者： ZAHRA Habibi hadi Zayyani MOHAMMAD Shams Esfand Abadi Research Institute for Information and Communications Technologies Academic Center for EducationCulture and ResearchTehran ***Iran Department of Electrical and Computer Engineering Qom University of TechnologyQom 371951519Iran Faculty of Electrical Engineering Shahid Rajaee Teacher Training UniversityTehran ***Iran

This paper presents a new subband adaptive filter(SAF)algorithm for system identification scenario under impulsive interference,named generalized continuous mixed p-norm SAF(GCMPN-SAF)*** proposed algorithm uses a GCMPN cost function to combat the impul-sive *** further accelerate the convergence rate in the sparse and the block-sparse system identification processes,the proportionate versions of the proposed algorithm,the L0-norm GCMPN-SAF(L0-GCMPN-SAF)and the block-sparse GCMPN-SAF(BSGCMPN-SAF)algorithms are also ***,the convergence analysis of the proposed algorithm is *** results show that the proposed algorithms have a better performance than some other state-of-the-art algorithms in the literature with respect to the convergence rate and the tracking capability.

关键词： subband adaptive filter(SAF) generalized continuous mixed p-norm(GCMPN) sparse system block-sparse system impulsive interference

Effect of constructing twin tunnels under a building supported by pile foundations in the Sydney central business district

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Underground Space 2019年第4期4卷 261-276页

作者： hadi Khabbaz Robert Gibson Behzad Fatahi School of Civil and Environmental Engineering University of Technology Sydney(UTS)Australia

In congested cities such as Sydney,competition for underground space escalates within the built environment because various assets require finite geotechnical strength and *** problems such as damage to buildings may develop when high-rise buildings on piled foundations are subject to ground movements as tunnels are *** paper focuses on the risks of tunneling beneath Sydney’s Martin Place and how buildings are subject to additional loads caused by *** key objective of this study is to improve the understanding of tunnel-rock-pile interactions and to encourage sustainable development.A finite element model is developed to predict the interaction between tunnel construction and piled *** tunnel,rock,and pile components are studied separately and are then combined into a single *** ground model is based on the characteristics of Hawkesbury Sandstone and is developed through a desktop *** piles are designed using Australian Standards and observations of high-rise *** tunnel construction is modeled based on the construction sequence of a tunnel boring *** combining the components,a parametric study on the relationship between tunnel location,basements,and piles is *** findings,thus far,show that tunneling can increase the axial and flexural loads of piles,where the additional loading exceeds the structural capacity of some piles,especially those that are close to basement *** parametric study reveals a strong relationship between tunnel depth and lining stresses,while the relationship between tunnel depth and induced pile loads is less ***,the horizontal tunnel position relative to piles shows a stronger relationship with pile *** research into tunnel-rock-pile interactions is recommended,especially beneath basements,to substantiate the results of this study.

关键词： Twin tunnels Finite element modeling Pile foundations Plaxis Sydney central business district

Investigation of the stability and hydrodynamics of Tetrosomus gibbosus carapace in different pitchangles

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Journal of Hydrodynamics 2019年第2期31卷 368-378页

作者： Mahyar Malekidelarestaqi Alireza Riasi hadi Moradi Mohammad Samadpour School of Mechanical Engineering University of TehranTehranIran Intelligent Systems Research Institute Sungkyunkwan UniversitySeoulKorea School of Electrics and Computer Engineering University of TehranTehranIran School of Mechanical Engineering Amirkabir University of TechnologyTehranIran

In this paper,stability properties of Tetrosomus gibbosus have been experimentally and numerically studied in pitching *** fish lives in southern offshores of *** usually live in extremely turbulent parts of seas and oceans,with high stability and maneuverability that has caught the attention of *** body shape let them swim with a quite rapid *** on Boxfishes have had influences on automotive and marine *** CAD file of the boxfish was created using optical *** a model was built and tested in a subsonic wind tunnel and a numerical study was conducted in virtual wind *** experimental results are consistent with the numerical ones and also support the findings of other studies on similar *** results show that the flow around the fish,which is a consequence of its body shape,tries to maintain the stable position of the fish by resisting against the external force tilting the fish from its stable horizontal *** ventral and dorsal keels of the boxfish generate column-like vortices in horizontal direction which play an imperative role in maintaining the stability of the fish.

关键词： Boxfish Tetrosomus gibbosus humpback turretfish hydrodynamic stability experimental fluid mechanics bio-inspired engineering

Control over hysteresis curves and thresholds of optical bistability in different semiconductor double quantum wells

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Chinese Physics B 2015年第8期24卷 373-380页

作者： Hamedi H R Mehmannavaz M R Afshari hadi Institute of Theoretical Physics and Astronomy Vilnius University Young Researchers and Elite Club Mashhad Branch Islamic Azad University Research Institute for Applied Physics University of Tabriz

The effects of optical field on the phenomenon of optical bistability(OB) are investigated in a K-type semiconductor double quantum well(SDQW) under various parametric conditions. It is shown that the OB threshold can be manipulated by increasing the intensity of coupling field. The dependence of the shift of OB hysteresis curve on probe wavelength detuning is then explored. In order to demonstrate controllability of the OB in this SDQW, we compare the OB features of three different configurations which could arise in this SDQW scheme, i.e., K-type, Y-type, and inverted Y-type systems. The controllability of this semiconductor nanostructure medium makes the presented OB scheme more valuable for applications in all-optical switches, information storage, and logic circuits of all optical information processing.

关键词： optical bistability semiconductor double quantum wells K-type Y-type and inverted Y-type schemes OB threshold intensity

Reservoir volume optimization and performance evaluation of rooftop catchment systems in arid regions: A case study of Birjand, Iran

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Water Science and Engineering 2017年第2期10卷 125-133页

作者： Zinat Komeh hadi Memarian Seyed Mohammad Tajbakhsh Faculty of Natural Resources and Environment University of Birjand Birjand 97175 Iran

This study evaluated the performance of rooftop catchment systems in securing non-potable water supply in Birjand, located in an arid area in southeastern Iran. The rooftop catchment systems at seven study sites of different residential buildings were simulated for dry, normal, and wet water years, using 31-year rainfall records. The trial and error approach and mass diagram method were employed to optimize the volume of reservoirs in five different operation scenarios. Results showed that, during the dry water year from 2000 to 2001, for reservoirs with volumes of 200-20000 L, the proportion of days that could be secured for non-portable water supply was on average computed to be 16.4%-32.6% across all study sites. During the normal water year from 2009 to 2010 and the wet water year from 1995 to 1996, for reservoirs with volumes of 200-20000 L, the proportions were 20.8%-69.6% and 26.8%-80.3%, respectively. Therefore, a rooftop catchment system showed a high potential to meet a significant portion of non-potable water demand in the Birjand climatic region. Reservoir volume optimization using the mass diagram method produced results consistent with those obtained with the trial and error approach, except at sites #1, #2, and #5. At these sites, the trial and error approach performed better than the mass diagram method due to relatively high water consumption. It is concluded that the rooftop catchment system is applicable under the same climatic conditions as the study area, and it can be used as a drought mitigation strategy as well.

关键词： Mass diagram analysis Non-potable water demand Reservoir volume optimization Rooftop catchment Rainwater harvesting

Role of heat balance on the microstructure evolution of cold spray coated AZ31B with AA7075

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Journal of Magnesium and Alloys 2021年第4期9卷 1467-1478页

作者： Bahareh Marzbanrad Mohammad hadi Razmpoosh Ehsan Toyserkani Hamid Jahed Mechanical and Mechatronics Engineering Department University of WaterlooCanada

A promising solid-state coating mechanism based on the cold spray technique provides highly advantageous conditions on thermal-sensitive magnesium *** study the effect of heat balance in cold spray coating on microstructure,experiments were designed to successfully coat AA7075 on AZ31B with two different heat balance conditions to yield a coated sample with tensile residual stress and a sample with compressive residual stress in both coating and *** effects of coating temperature on the microstructure of magnesium alloy and the interfaces of coated samples were then analyzed by SEM,EBSD,TEM in high-and low-heat input coating *** interface of the AA7075 coating and magnesium alloy substrate under both conditions consists of a narrow-band layer with very fine grains,followed by columnar grains of magnesium that have grown perpendicular to the *** higher temperatures,this layer became *** intermetallic phase was detected at the interface under either *** is shown that the microstructure of the substrate was affected by coating temperature,leading to stress relief,dynamic recrystallization and even dynamic grain growth of magnesium under high *** the heat input and increasing the heat transfer decreased microstructural changes in the substrate.

关键词： Cold spraying Heat balance Microstructural analysis Coating interface Magnesium Alloy AZ31B Residual Stress