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Interplay between temperature-dependent strengthening mechanisms and mechanical stability in high-performance austenitic stainless steels

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2182-2188页

作者： Mohammad Javad Sohrabi Hamed Mirzadeh Saeed sadeghpour Milad Zolfipour Aghdam Abdol Reza Geranmayeh Reza Mahmudi School of Metallurgy and Materials Engineering College of EngineeringUniversity of Tehran14395-515 TehranIran Centre for Advanced Steels Research Materials and Mechanical EngineeringUniversity of Oulu90014 OuluFinland Department of Mechanical Engineering College of EngineeringUniversity of Tehran14395-515 TehranIran

The effects of deformation temperature on the transformation-induced plasticity(TRIP)-aided 304L,twinning-induced plasti-city(TWIP)-assisted 316L,and highly alloyed stable 904L austenitic stainless steels were compared for the first time to tune the mechan-ical properties,strengthening mechanisms,and strength-ductility *** this purpose,the scanning electron microscopy(SEM),electron backscattered diffraction(EBSD),X-ray diffraction(XRD),tensile testing,work-hardening analysis,and thermodynamics calcu-lations were *** induced plasticity effects led to a high temperature-dependency of work-hardening behavior in the 304L and 316L stainless *** the deformation temperature increased,the metastable 304L stainless steel showed the sequence of TRIP,TWIP,and weakening of the induced plasticity mechanism;while the disappearance of the TWIP effect in the 316L stainless steel was also ***,the solid-solution strengthening in the 904L superaustenitic stainless steel maintained the tensile properties over a wide temper-ature range,surpassing the performance of 304L and 316L stainless *** this regard,the dependency of the total elongation on the de-formation temperature was less pronounced for the 904L alloy due to the absence of additional plasticity *** results re-vealed the importance of solid-solution strengthening and the associated high friction stress for superior mechanical behavior over a wide temperature range.

关键词： austenitic stainless steels mechanical behavior stacking fault energy metastability mechanical twinning

Bistability and oscillations in co-repressive synthetic microbial consortia

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Frontiers of Electrical and Electronic Engineering in China 2017年第1期5卷 55-66页

作者： mehdi sadeghpour.alan veliz-cuba Gabor Orosz Kresimir Josic Matthew R. Bennett Department of Mechanical Engineering University of Michigan Ann Arbor MI 48109 USA Department of Mathematics University of Dayton Dayton OH 45469 USA Department of Mathematics University of Houston Houston TX 77204 USA Department of Biology and Biochemistry University of Houston Houston TX 77204 USA Department of Biosciences Rice University Houston TX 77251-1892 USA Department of Bioengineering Rice University Houston TX 77251-1892 USA

Background： Synthetic microbial consortia are conglomerations of genetically engineered microbes programmed to cooperatively bring about population-level phenotypes. By coordinating their activity, the constituent strains can display emergent behaviors that are difficult to engineer into isogenic populations. To do so, strains are engineered to communicate with one another through intercellular signaling pathways that depend on cell density. Methods： Here, we used computational modeling to examine how the behavior of synthetic microbial consortia results from the interplay between population dynamics governed by cell growth and internal transcriptional dynamics governed by cell-ceil signaling. Specifically, we examined a synthetic microbial consortium in which two strains each produce signals that down-regulate transcription in the other. Within a single strain this regulatory topology is called a ＂co-repressive toggle switch＂ and can lead to bistability. Results： We found that in co-repressive synthetic microbial consortia the existence and stability of different states depend on population-level dynamics. As the two strains passively compete for space within the colony, their relative fractions fluctuate and thus alter the strengths of intercellular signals. These fluctuations drive the consortium to alternative equilibria. Additionally, if the growth rates of the strains depend on their transcriptional states, an additional feedback loop is created that can generate oscillations. Conclusions： Our findings demonstrate that the dynamics of microbial consortia cannot be predicted from their regulatory topologies alone, but are also determined by interactions between the strains. Therefore, when designing synthetic microbial consortia that use intercellular signaling, one must account for growth variations caused by the production of protein.

关键词： synthetic biology microbial consortia quorum sensing relaxation oscillations

DEA/TEAOH templated synthesis and characterization of nanostructured NiAPSO-34 particles:Effect of single and mixed templates on catalyst properties and performance in the methanol to olefin reaction

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Particuology 2015年第2期13卷 69-81页

作者： Parisa sadeghpour Mohammad Haghighi Chemical Engineering Faculty Sahand University of Technology Reactor and Catalysis Research Center(RCRC) Sahand University of Technology

A nanostructured NiAPSO-34 catalyst was hydrothermally synthesized and the effect of the template （diethylamine （DEA）, tetraethylammonium hydroxide （TEAOH） and DEA/TEAOH） on the physicochemical properties and catalytic performance in the methanol to olefin （MTO） reaction was investigated. The samples were characterized by X-ray diffraction, field emission scanning electron microscopy （FESEM）, particle size distribution analysis, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller anal- ysis and Fourier transform infrared spectroscopy. The X-ray diffraction patterns indicated a higher crystallinity and larger crystallite size for the catalyst synthesized using the DEA template. The FESEM results indicated that the nature of the template could affect the morphology of the nanostructured NiAPSO-34 catalyst because of its effect on the rate of crystal growth. The catalytic performance of the samples was studied in the MTO reaction at atmospheric pressure and a space velocity of 4200 cm^3 /（g h^-1 ） in a fixed bed reactor. The stability and activity of the NiAPSO-34 catalyst were improved using the DEA template because of its higher crystallinity, surface area and the greater extent of Ni incorporation into its framework. The possible stages of synthesis and the reaction mechanism for the MTO process over NiAPSO-34 are discussed in detail.

关键词： NiAPSO-34 DEA TEAOH Methanol Olefins MTO

Effect of hot rolling and annealing temperatures on the microstructure and mechanical properties of SP-700 alloy

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International Journal of Minerals,Metallurgy and Materials 2020年第3期27卷 374-383页

作者： Parnia Parvizian Maryam Morakabati Saeed sadeghpour Metallic Materials Research Center Malek Ashtar University of Technology

The effect of rolling temperature on both two-and single-phase regions and annealing in a temperature range of 700–950°C on the microstructure and mechanical properties of Ti-5 Al-4 V-2 Fe-1 Mo alloy was investigated. The results indicated that the best balance of strength and ductility is obtained by rolling in the two-phase region due to the globularization of the alpha phase and increase in its volume fraction. After rolling in the two-phase region, the ductility of the specimens annealed at 700 to 800°C increased because of the finer size and globularized alpha phase, while the reduction in strength was attributed to a decrease in the alpha phase volume fraction. However, at 950°C, the strength increased and ductility dropped by the formation of acicular alpha phase due to an increase in the phase boundary area. Annealing and aging after rolling in the beta-phase region increased the strength and decreased the ductility, which is attributed to the formation of a secondary alpha phase. A combination of favorable yield strength(1113 MPa) and elongation(13.3%) was obtained through rolling at 850°C followed by annealing at 750°C and aging at 570°C.

关键词： beta-rich two phase Ti alloy thermomechanical processing tensile properties microstructure

Potential therapeutic applications for Terminalia chebula in Iranian traditional medicine

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Journal of Traditional Chinese Medicine 2016年第2期36卷 250-254页

作者： Assie Jokar Fatemeh Masoomi Omid sadeghpour Mohsen Nassiri-Toosi Shokouhsadat Hamedi Iranian Traditional Medicine Faculty Tehran University of Medical SciencesTehran ***Iran Department of Iranian Traditional Medicine Mazandaran University of Medical SciencesSari ***Iran Department of Traditional Pharmacy Traditional Medicine FacultyTehran University of Medical SciencesTehran ***Iran Herbal and Traditional Medicine Department Research Institute for Islamic and Complementary MedicineIran University of Medical SciencesTehran ***Iran Department of Internal Medicine Tehran University of Medical SciencesTehran ***Iran Department of Persian Pharmacy School of Persian and Complementary MedicineMashhad University of Medical SciencesMashhad ***Iran

Terminalia chebula(family:Combretaceae)is widely used in the traditional medicine of India and Iran to treat diseases that include dementia,constipation,and *** tree is known in Iranian traditional medicine(ITM)as halileh or halilaj and the fruit is used to develop *** is described in ITM as an astringent that has a"cold"and"dry"*** to the medicinal properties of Terminalia chebula were collected from important ITM sources and from modern medical databases(Pub Med,Scirus,Science Direct,and Scopus).The medicinal properties described for thistree in ITM were compared with those reported in studies of modern *** results confirm that the tree referred to as halileh in traditional books is the Terminalia chebula used in present-day *** that have not been evaluated in modern phytotherapy but have been traditionally treated with Terminalia chebula include fever,and psychological and psychiatric *** article confirms the medicinal uses of Terminalia chebula.

关键词： Fructus chebula Phytochemicals Phar macology Iranian traditional medicine

New approach for time-resolved and dynamic investigations on nanoparticles agglomeration

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Nano Research 2020年第10期13卷 2847-2856页

作者： Neda Iranpour Anaraki Amin sadeghpour Kamran Iranshahi Claudio Toncelli Urszula Cendrowska Francesco Stellacci Alex Dommann Peter Wick Antonia Neels Center for X-ray Analytics EmpaSwiss Federal Laboratories for Materials Science and Technology St.Gallen 9014Switzerland Laboratory of Particles Biology Interactions EmpaSwiss Federal Laboratories for Materials Science and TechnologySt.Gallen 9014Switzerland Department of Chemistry University of FribourgChemin du MuseeFribourg 1700Switzerland Laboratory for Biomimetic Membranes and Textiles EmpaSwiss Federal Laboratories for Materials Science and TechnologySt.Gallen 9014Switzerland Department of Environmental Systems Science Swiss FPederal Institute of TechnologyETH-ZurichZurich 8092Switzerland Institute of Materials EPFLLausanne 1015Switzerland Cellular and Biomedical Sciences Faculty of MedicineUniversity of BernBern 3012Swizerland

Nanoparticle (NP) colloidal stability plays a crucial role in biomedical application not only for human and environmental safety but also for NP efficiency and functionality. NP agglomeration is considered as a possible process in monodispersed NP colloidal solutions, which drastically affects colloidal stability. This process is triggered by changes in the physicochemical properties of the surrounding media, such as ionic strength (IS), pH value, or presence of biomolecules. Despite different available characterization methods for nanoparticles (NPs), there is a lack of information about the underlying mechanisms at the early stage of dynamic behaviors, namely changing in NP size distribution and structure while placing them from a stable colloidal solution to a new media like biological fluids. In this study, an advanced in situ approach is presented that combines small angle X-ray scattering (SAXS) and microfluidics, allowing label-free, direct, time-resolved, and dynamic observations of the early stage of NP interaction/agglomeration initiated by environmental changes. It is shown for silica NPs that the presence of protein in the media enormously accelerates the NP agglomeration process compared to respective changes in IS and pH. High IS results in a staring agglomeration process after 40 min, though, in case of protein presence in media, this time decreased enormously to 48 s. These time scales show that this method is sensitive and precise in depicting the dynamics of fast and slow NP interactions in colloidal conditions and therefore supports understanding the colloidal stability of NPs in various media concluding in safe and efficient NP designing for various applications.

关键词： microfluidic small-angle X-ray scattering(SAXS) in situ dynamic measurements nanoparticle agglomeration biological environment label-free

Epicardial Versus Endocardial Pacemakers in the Pediatric Population:A Comparative Inquiry

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Congenital Heart Disease 2021年第6期16卷 573-584页

作者： Mohammadrafie Khorgami Ali sadeghpour Tabaei Elio Caruso Silvia Farruggio Negar Omidi Maryam Moradian Behzad Mohammadpour Ahranjani Zahra Khajali Rahele Zamani Cardiovascular Medical and Research Center Iran University of Medical SciencesTehranIran Cardiovascular Surgery Department Rajaie Cardiovascular Medical and Research CenterIran University of Medical SciencesTehranIran Department of Pediatric Cardiology Mediterranean Pediatric Cardiology Center“Bambin Gesù”San Vincenzo HospitalTaorminaItaly Cardiac Primary Prevention Research Center Tehran Heart Center and Department of CardiologySchool of MedicineTehran University of Medical SciencesTehranIran Pediatric Cardiology Bahrami Children’s HospitalTehran University of Medical ScienceTehranIran Adult Congenital Heart Disease Department Rajaie Cardiovascular Medical and Research CenterIran University of Medical SciencesTehranIran

Background:Most children in need of cardiac pacemakers remain dependent on the function of the permanent from childhood to *** sought to evaluate and compare the function between epicardial and endocardial pacemakers in pediatric groups with different ***:Between 2012 and 2018,this single-canter study evaluated 44 pediatric patients with indications for epicardial or endocardial ***:The 2 groups,at a median age of 5(0.1–16)years,were compared concerning the characteristics of the leads used(n=80:bipolar,unipolar,steroid-eluting,and non–steroid-eluting),survival data,and *** reason for pacemaker implantation was congenital complete heart block in 11(25%)cases and postoperative heart block in 33(75%)*** commonest congenital heart disease accompanied by postoperative block was the ventricular septal *** the endocardial lead group,the mean ventricular pacing threshold immediately after the implantation and during the follow-up was less than that in the epicardial lead group(0.75 vs.0.81 V;P=0.01 and 0.8 vs.2.4 V;P=0.001).During the follow-up,the mean battery longevity was better in the endocardial group(last visit:6.7 endocardial vs.3.3 years epicardial).Lead failure was commoner in the epicardial pacemaker,and chronic high-pacing threshold pattern was seen in 14 patients in this *** 3 years,freedom from lead failure was 94%and 63%in the endocardial and epicardial ***:Pacemakers with endocardial bipolar steroid-eluting leads showed better lead characteristics regarding survival and battery longevity than epicardial pacemakers without these lead *** appropriate pacemaker type should be selected based on the patient’s condition.

关键词： Pacemaker congenital heart defects cardiac pacing pediatrics

AOQ and ATI for Double Sampling Plan with Using Fuzzy Binomial Distribution

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AOQ and ATI for Double Sampling Plan with Using Fuzzy Binomi...

A Novel Approach for Finding a Shortest Path in a Mixed Fuzzy Network

2010 International Conference on Intelligent Computing and Cognitive Informatics (ICICCI 2010)

作者： Ezzatallah Baloui Jamkhaneh Bahram sadeghpour Gildeh Department of Statistics Islamic Azad UniversityGhaemshahr BranchGhaemshahrIran Department of Statistics Faculty of Basic ScienceUniversity of MazandaranBablosarIran

in this paper we introduce the average outgoing quality （AOQ） and average total inspect （ATI） for double sampling plan when that proportion nonconforming items is fuzzy *** have shown that AOQ and ATI curves of the plan are like a band having high and low bounds and if the process quality is very good or very bad,then AOQ bands will be lower *** the decreasing the quality of process the bandwidth of FATI will narrower,and with the increasing the size of lot if others parameter be fixed,this width be wider.

关键词： Statistical quality control acceptance single sampling average outgoing quality average total inspection fuzzy number.

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Wireless Sensor Network 2010年第2期2卷 148-160页

作者： Ali Tajdin Iraj Mahdavi Nezam Mahdavi-Amiri Bahram sadeghpour-Gildeh Reza Hassanzadeh 不详

We present a novel approach for computing a shortest path in a mixed fuzzy network, network having various fuzzy arc lengths. First, we develop a new technique for the addition of various fuzzy numbers in a path using -cuts. Then, we present a dynamic programming method for finding a shortest path in the network. For this, we apply a recently proposed distance function for comparison of fuzzy numbers. Four examples are worked out to illustrate the applicability of the proposed approach as compared to two other methods in the literature as well as demonstrate the novel feature offered by our algorithm to find a fuzzy shortest path in mixed fuzzy networks with various settings for the fuzzy arc lengths.

关键词： Fuzzy Numbers -Cut Shortest Path Dynamic Programming