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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Rostaniha
- نوع مقاله: Journal Article
- کلمات کلیدی: Phragmites australis,Soil features,presence and absence,Shahriyar rangelands,Salsola kali,Ephedra distachya and Tamarix ramosissima
- چکیده: در مدیریت و برنامهریزی استفاده بهینه از منابع طبیعی، تعیین عواملی که حضور و پراکنش گیاهان را کنترل میکنند، همواره باید مد نظر قرار گرفته و در برنامهریزی استفاده از سرزمین مورد توجه باشد. تحقیق حاضر با همین هدف به بررسی رابطه چند گونه گیاهی شاخص مناطق خشک و نیمهخشک با برخی عوامل مختلف توپوگرافی و خاکی در مراتع چهارباغ شهریار استان تهران پرداخته است. بدین منظور پس از مطالعات اولیه و انتخاب گونههای گیاهی مهم، نمونهبرداری در رویشگاه هر گونه گیاهی در طول 3 تا 4 ترانسکت نواری 200 متری به روش تصادفی- سیستماتیک در منطقه معرف هر تیپ انجام گرفت.
- چکیده انگلیسی: In order to obtain an optimum management of natural resources, determination of variables that control plant presence and distribution is needed. In the present research, the relationship between some character plants of drylands and some soil and environmental variables were investigated. After primary survey and selection of main plant species, sampling was done in each vegetation type within 3-4 transects (200 m length) by randomized-systematic method.
- انتشار مقاله: 01-06-1388
- نویسندگان: M. Jafari,S. Zare,A. Tavili,H.R. Abbasi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Operation and Automation in Power Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Fuel cell,Photovoltaic,Hybrid renewable energy,DC/DC converter,multiport converters
- چکیده: این مقاله یک مبدل جدید DC/DC چند دریچه ای را که مناسب برای ارتباط در سیستم های انرژی نو هایبریدی را ارائه می دهد. مبدل شامل سه دریچه با پخش توان یک طرفه است که دو تای آنها به عنوان ورودی دریچه می باشند و متصل به دو منبع انرژی مستقل در حالی که سومین برابر با دریچه خروجی استکه یک بار مستقل را تغذیه می کند. به علاوه، مبدل پیشنهادی شامل یک دریچه پخش توان دو طرفه برای شارژ و تخلیه منبع انرژی ذخیره ساز (باتری) به کار گرفته می شود. اضافه بر ساختار چند دریچه ای، بهره ولتاژ با مقدار بالا نیز دیگر مزیت مبدل به حساب می آید. سیستم هایبرید شامل پیل سوختی، پنل های خورشیدی و یک مجموعه از باتری می باشد. وضعیت های عملکردی متفاوت مورد مطالعه قرار گرفته و یک سیستم کنترلی بر مینای شبکه های مجزا ارائه شده است. سیستم کنترلی قادر به جستجو و استخراج بیشترین توان از پنل های خورشیدی ، تنظیم توان تولیدی پیل سوختی و حالت های شارژ و تخلیه باتری می باشد. به منظور کنترل حالت های کاری از مبدل پیشنهاد شده، یک روش تنظیم مدیریت توان نیز بیان شده است. در ضمن، مدل سیگنال کوچک برای مبدل ارائه شده است. و دیاگرام بود آن رسم شده است و به کمک آن کنترلر ولتاژ خروجی طراحی شده است. شبیه سازی و نتایج آزمایشگاهی برای ارزیابی تحلیل و امکان سنجی سیسنم ذکر شده به کار گرفته شده است. نتایج عملکرد صحیح مبدل را تایید می کند و شبیه سازی و نتایج تئوری را تصدیق می کند.
- چکیده انگلیسی: This paper presents a novel multi-port DC/DC converter which is suitable to be used as the interface of hybrid renewable energy systems. The converter contains three unidirectional power flow ports which two of them are input ports and are connected to two independent energy sources while the third one is the output port that feeds a standalone load. Furthermore, the proposed converter contains a bidirectional power flow port to charge/discharge an energy storage system (battery). In addition to multi-port structure, high boost value of voltage gain is the other merit of the converter. Hybrid system is composed of fuel cell (FC), photovoltaic (PV) panels and a battery pack. Different operating states are discussed, and a control system based on decoupling networks is presented. The control system is able to seek and extract maximum power of PV panel, adjust generated power of FC, and handle charging and discharging modes of battery. In order to control operating modes of the proposed converter, a power management method is also presented. By the way, small signal model is presented for the converter.The bode diagram has been plotted from the small signal model. Then the controller it was designed from the bode diagram. The results of simulation by the PI controller are presented. Also, the simulation results by P&O algorithm for the converter has been evaluated. Several Simulation and experimental tests have been carried out to evaluate the analysis and feasibility of the aforementioned system. The results verify well performance of the converter and confirm the simulations and theoretical results.
- انتشار مقاله: 11-10-1348
- نویسندگان: E. Seifi,A. Rajaei,S. Zare,A. Nabinejad,S. Nobahar
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Operation and Automation in Power Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Fuel cell,Photovoltaic,Hybrid renewable energy,DC/DC converter,multiport converters
- چکیده: این مقاله یک مبدل جدید DC/DC چند دریچه ای را که مناسب برای ارتباط در سیستم های انرژی نو هایبریدی را ارائه می دهد. مبدل شامل سه دریچه با پخش توان یک طرفه است که دو تای آنها به عنوان ورودی دریچه می باشند و متصل به دو منبع انرژی مستقل در حالی که سومین برابر با دریچه خروجی استکه یک بار مستقل را تغذیه می کند. به علاوه، مبدل پیشنهادی شامل یک دریچه پخش توان دو طرفه برای شارژ و تخلیه منبع انرژی ذخیره ساز (باتری) به کار گرفته می شود. اضافه بر ساختار چند دریچه ای، بهره ولتاژ با مقدار بالا نیز دیگر مزیت مبدل به حساب می آید. سیستم هایبرید شامل پیل سوختی، پنل های خورشیدی و یک مجموعه از باتری می باشد. وضعیت های عملکردی متفاوت مورد مطالعه قرار گرفته و یک سیستم کنترلی بر مینای شبکه های مجزا ارائه شده است. سیستم کنترلی قادر به جستجو و استخراج بیشترین توان از پنل های خورشیدی ، تنظیم توان تولیدی پیل سوختی و حالت های شارژ و تخلیه باتری می باشد. به منظور کنترل حالت های کاری از مبدل پیشنهاد شده، یک روش تنظیم مدیریت توان نیز بیان شده است. در ضمن، مدل سیگنال کوچک برای مبدل ارائه شده است. و دیاگرام بود آن رسم شده است و به کمک آن کنترلر ولتاژ خروجی طراحی شده است. شبیه سازی و نتایج آزمایشگاهی برای ارزیابی تحلیل و امکان سنجی سیسنم ذکر شده به کار گرفته شده است. نتایج عملکرد صحیح مبدل را تایید می کند و شبیه سازی و نتایج تئوری را تصدیق می کند.
- چکیده انگلیسی: This paper presents a novel multi-port DC/DC converter which is suitable to be used as the interface of hybrid renewable energy systems. The converter contains three unidirectional power flow ports which two of them are input ports and are connected to two independent energy sources while the third one is the output port that feeds a standalone load. Furthermore, the proposed converter contains a bidirectional power flow port to charge/discharge an energy storage system (battery). In addition to multi-port structure, high boost value of voltage gain is the other merit of the converter. Hybrid system is composed of fuel cell (FC), photovoltaic (PV) panels and a battery pack. Different operating states are discussed, and a control system based on decoupling networks is presented. The control system is able to seek and extract maximum power of PV panel, adjust generated power of FC, and handle charging and discharging modes of battery. In order to control operating modes of the proposed converter, a power management method is also presented. By the way, small signal model is presented for the converter.The bode diagram has been plotted from the small signal model. Then the controller it was designed from the bode diagram. The results of simulation by the PI controller are presented. Also, the simulation results by P&O algorithm for the converter has been evaluated. Several Simulation and experimental tests have been carried out to evaluate the analysis and feasibility of the aforementioned system. The results verify well performance of the converter and confirm the simulations and theoretical results.
- انتشار مقاله: 11-10-1348
- نویسندگان: E. Seifi,A. Rajaei,S. Zare,A. Nabinejad,S. Nobahar
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Science and Technology A:Science
- نوع مقاله: Journal Article
- کلمات کلیدی: Cytotoxicity,Pt(II)/Pd(II) complexes,DNA binding,thermodynamic/binding parameters
- چکیده:
- چکیده انگلیسی: Two newly-created water-soluble complexes of palladium(II)/platinum(II)-dithiocarbamate, [Pd/Pt(phen)(pyr-dtc)]NO3 (phen = 1,10-phenanthroline and pyr-dtc = pyrrolidinedithiocarbamate) were synthesized. Also, their chemical characteristics are reported in the current research paper. In these complexes, the dithiocarbamato ligand coordinates to Pt(II) or Pd(II) center with two sulfur atoms as bidentate. They were examined for their cytotoxic properties against chronic myelocytic leukemia K562 cell lines. These complexes showed 50% cytotoxic concentration (Cc50) values much lower than those of cisplatin. The interactions of the two complexes with calf thymus DNA (CT-DNA) were investigated using UV-vis absorption, fluorescence emission, ethidium bromide displacement and gel filtration techniques. The results suggest that these complexes cooperatively bind with and denature the DNA at low concentrations and interact with CT-DNA in the intercalation mode. Gel filtration studies indicate that the binding of complexes with DNA is strong enough not to break readily.
- انتشار مقاله: 11-09-1392
- نویسندگان: S. Shahraki,H. Mansouri-Torshizi,A. Heydari,A. Ghahghaei,A. Divsalar,A. A. Saboury,H. Ghaemi,M. Doostkami,S. Zareian
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Medical Sciences
- نوع مقاله: Journal Article
- کلمات کلیدی:
- چکیده:
- چکیده انگلیسی: Background: There is a rapidly growing trend in the consumption of herbal remedies in the developing countries. The Phoenix dactylifera date palm pollen (DPP) is used in the traditional medicine for male infertility. The aim of this study was to determine the effects of orally administered DPP on the reproductive system of adult male rats. Methods: Fifty Sprague-Dawley rats were maintained according to standard laboratory conditions. They were divided into five groups (n=10) and received daily gavages of aqueous suspensions DPP containing 30, 60, 120 and 240 mg/kg, for 35 consecutive days. At the end the sperm was collected from ductus deferens under anesthesia and their numbers, motility, and morphology were determined under light microscopy. The DNA integrity or denaturation was also evaluated by acridine orange staining. The weight of the testis and reproductive appendages was also determined, and after tissue processing, their histology were studied by light microscope. Results: The comparative evaluation between control and experimental groups revealed that consumption of DPP suspensions improved the sperm count, motility, morphology, and DNA quality with a concomitant increase in the weights of testis and epididymis. It did not significantly affect the weight of the prostate and the seminal vesicle or the histology of the reproductive tissues. Conclusion: Date palm pollen seems to cure male infertility by improving the quality of sperm parameters. However, further studies are needed to see its beneficial effects in man.Iran J Med Sci 2006; 31(4): 208-212. Keywords ● Date palm pollen ● male reproductive system ● sperm ● infertility
- انتشار مقاله: 09-06-1394
- نویسندگان: S. Bahmanpour,T. Talaei,Z. Vojdani,M.R. Panjehshahin,A. Poostpasand,S. Zareei,M. Ghaeminia
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Iron and Steel Society of Iran
- نوع مقاله: Journal Article
- کلمات کلیدی: Dual phase steels,Finite element microstructural modeling,Ferrite phase inhomogeneity
- چکیده:
- چکیده انگلیسی: The microstructure of dual phase steels can be considered as a matrix of ferrite phase reinforced by martensite particles. Recent measurements show that the mechanical properties of the ferrite phase are changed with the distance from the martensite grains. In this paper, a new method has been proposed to consider this phenomenon in finite element modeling of dual phase steels microstructure. In this method, ferrite mechanical properties were imported to the model as a continuous function of the distance from martensite boundary. A unit cell model of dual phase steel was constructed based on the experimental measurements. The tensile test was simulated in both cases of considering the ferrite phase as the homogeneous and inhomogeneous matrix. It was observed that by considering the ferrite phase inhomogeneity, the model could predict macro stress precisely. Considering the ferrite phase inhomogeneity also led to the better prediction of shear band formation in the unit cell, as compared to the other model. A different stress distribution prediction was also observed in these two models and ferrite phase maximum stress was higher when inhomogeneity was included. These observations could be crucial in the investigation of dual phase steels damage. It was observed that martensite volume fraction and the grain size had a stronger effect on the model with the inhomogeneous ferrite phase.
- انتشار مقاله: 03-05-1395
- نویسندگان: S. Zarei,R. Jafari Nedoushan
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: delay,Doppler,noise,Bistatic passive Radar,Ambiguity Function
- چکیده:
- چکیده انگلیسی: In this paper a novel method for detecting targets in inactive radars is presented. In this method, the time history of cellsof the ambiguity function is used for detection. For this purpose, the cell history is considered as a random field. Then, using adaptive filter, the string time of the desired target are separated from the string time of noise and clusters in the environment. In order to evaluate the performance of the proposed method for an environment including three targets with simulated different distances and speeds, the results were compared with the other two methods at the same conditions. Based on the results obtained, this method has the ability to detect targets for SCNRs of up to -10 dB for all three values of the probability of false alarms. The obtained results also showed the superiority of the proposed method compared to other alternatives in such manner. Accordingly, the probability of detection for the proposed method at least 12.5 percent better than ACM and 8 percent better than NNTD. It also shows that for SCNRs larger than zero dB, this method has a 100% detection capability.
- انتشار مقاله: 11-10-1348
- نویسندگان: M Kafi,J. Ranjbar,J. Khalilpour,S. Zarezade
- مشاهده
- جایگاه : پژوهشی
- مجله: Desert
- نوع مقاله: Journal Article
- کلمات کلیدی: Region,Production,Steppic rangelands,Key range species,Grazing capacity
- چکیده:
- چکیده انگلیسی: Forage production of rangelands differs during different times of grazing season and in the same month of different years. In range management projects, grazing capacity calculated once during the grazing season, which coincides with the maximum production of rangeland species. This may cause more livestock entry into the rangeland during the grazing season, leading to more degradation. Therefore, it is necessary to measure forage production during the months of grazing season over a few years, based on which the long-term grazing capacity of key range species could be estimated. Production variations of the key species, namely Artemisia sieberi, Salsola laricina, and Stipa hohenackeriana were investigated in Khoshkerood-e-Saveh site in growth and grazing season over the course of three years. For this purpose, the production of each species measured in a one-hectare exclosure with one month intervals until the growth dormancy. After air-drying, forage production was analyzed by SAS software. Based on the results, due to the high variability of monthly and annual precipitation in the region, forage production of key range species had significant differences at P ≤5% level. The maximum and minimum mean production (543 and 388 kg/ha) belonged to 2009 and 2008, respectively. According to the production fluctuation in different years, it is recommended that range management plans account for the long-term average of good production.
- انتشار مقاله: 20-07-1399
- نویسندگان: S. Zarekia,M. Akbarzadeh,A.A. Jamali
- مشاهده
- جایگاه : پژوهشی
- مجله: Archives of Razi Institute
- نوع مقاله: Journal Article
- کلمات کلیدی: Rat,Liver,Thioacetamide,Bone marrow,mesenchymal stem cell,Fibrosis
- چکیده:
- چکیده انگلیسی: The present study determined the regenerative effect of bone marrow-derived stem cells (BMSCs) on thioacetamide (TA)-induced liver fibrosis in rats. A total of 30 male Wistar rats were randomly divided into sham control and treatment groups. The rats of the sham control group were subdivided into three groups and sampled on the 14th, 18th, and 20th weeks after fibrosis induction. The rats of the treatment group were subdivided into two groups and sampled on the 4th and 6th weeks after BMSCs treatment. Fibrosis was induced by the intraperitoneal administration of 200 mg/kg of TA twice a week for a period of 14 weeks. All the animals underwent liver function tests and histopathologic evaluation 4 and 6 weeks after BMSCs transplantation. The BMSCs were characterized using osteogenic induction and reverse transcription-polymerase chain reaction. The BMSCs were plastic adherent, spindle-shaped, and positive for osteogenic differentiation. They expressed CD73 and were negative for CD45. The infiltration of inflammatory cells and deposition of collagen fibers were noticed after TA administration. A significant decline in inflammatory cells and a healing process were detected 4 weeks after cell transplantation. The amelioration in hepatic tissue was significant 6 weeks after cell therapy. Following the injection of BMSCs, a nonsignificant decrease was visible in aspartate transaminase level; however, this decline was significant for alanine aminotransferase level. The alkaline phosphatase and albumin levels showed an increasing trend after cell administration. The transplantation of BMSCs resulted in a significant regenerative effect after hepatic injuries. Therefore, it was shown that BMSCs transplantation can open a new window and be a therapy of choice in the amelioration of liver fibrosis.
- انتشار مقاله: 04-01-1396
- نویسندگان: D. Mehrabani,Z. Khajehahmadi,P Tajik,A. Tamadon,F. Rahmanifar,M. Ashraf,N. Tanideh,S. Zare
- مشاهده