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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: SCIENTIA IRANICA
- نوع مقاله: Journal Article
- کلمات کلیدی: Iran,Disaster management,earthquakes,Emergency Response,Response framework,Earthquake loss mitigation
- چکیده:
- چکیده انگلیسی: Earthquake is common natural disaster in Iran, often accompanied by huge damages, losses and casualties. Therefore, focusing on earthquake response management, and improving its effectiveness is an important issue for the national disaster management organization. This paper proposes a framework to improve this process in Iran. The proposed framework attempts to coordinate governmental and non-governmental organizations involved in earthquake response. It also allows governments to systematize the obligations and responsibilities of these organizations, and mitigate the earthquake fatalities and casualties. Moreover, this study discusses the key considerations for implementing the proposed framework, and analyzes it for distinct scales of earthquake.
- انتشار مقاله: 18-02-1397
- نویسندگان: Mehdi Najafi,Sassan Eshghi,Kourosh Eshghi
- مشاهده
- جایگاه : پژوهشی
- مجله: SCIENTIA IRANICA
- نوع مقاله: Journal Article
- کلمات کلیدی: Iran,Disaster management,earthquakes,Emergency Response,Response framework,Earthquake loss mitigation
- چکیده:
- چکیده انگلیسی: Earthquake is common natural disaster in Iran, often accompanied by huge damages, losses and casualties. Therefore, focusing on earthquake response management, and improving its effectiveness is an important issue for the national disaster management organization. This paper proposes a framework to improve this process in Iran. The proposed framework attempts to coordinate governmental and non-governmental organizations involved in earthquake response. It also allows governments to systematize the obligations and responsibilities of these organizations, and mitigate the earthquake fatalities and casualties. Moreover, this study discusses the key considerations for implementing the proposed framework, and analyzes it for distinct scales of earthquake.
- انتشار مقاله: 18-02-1397
- نویسندگان: Mehdi Najafi,Sassan Eshghi,Kourosh Eshghi
- مشاهده
- جایگاه : پژوهشی
- مجله: Mechanics of Advanced Composite Structures
- نوع مقاله: Journal Article
- کلمات کلیدی: Free vibration,sandwich panel,Electro-rheological
- چکیده:
- چکیده انگلیسی: In this study, the frequency response of rectangular sandwich plates with multi-layer face sheets and electrorheological (ER) fluid cores is investigated. The assumed electro-rheological fluid as a core is capable of changing the stiffness and damping of structures. In modelling the sandwich panel implemented for the first time, first-order shear deformation theory and the second Frostig's model are applied for the face sheets and thick cores, respectively. The sandwich panel under study is supposed to simply support boundary in all edges, and the Galerkin approach is implemented for discretizing the problem. In the result section, impacts of various parameters such as electric field, aspect ratio, the thickness of the ER layer, and thickness ratio on vibrational characteristics of the structure are discussed in detail. The obtained results highlight the notable effects of the electric field on natural frequencies, which can make the structure flexible within the desired range. It is also pointed out that the dynamic behavior and stability of the system can be controlled by changing the magnitude of the ER fluid layer.
- انتشار مقاله: 15-01-1399
- نویسندگان: Mehdi Keshavarzian,Mohammad Mehdi Najafizadeh,Korosh Khorshidi,Peyman Yousefi,Majid Alavi
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Mining and Geo-Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Graph theory,Open Pit,Dijkstra Algorithm,Optimization. Dynamic Programing
- چکیده:
- چکیده انگلیسی: In open-pit mine planning, the design of the most profitable ultimate pit limit is a prerequisite to developing a feasible mining sequence. Currently, the design of an ultimate pit is achieved through a computer program in most mining companies. The extraction of minerals in open mining methods needs a lot of capital investment, which may take several decades. Before the extraction, the pit limit, which influences the stripping ratio, damp locations, ore processing site and access routes, should be designed. So far, a large number of algorithms have been developed to optimize the pit limits. These algorithms are categorized into two groups: heuristic and rigorous. In this paper, a new approach is presented to optimize the pit limit based on Dijkstra’s algorithm which is based on mathematical relations. This algorithm was implemented on a 2D economic graph model and can find the true optimal solution. The results were compared with those from the dynamic programming (DP) algorithm. This algorithm showed to have less time complexity compared to the dynamic programming algorithm and to be easier to write dynamic computer programs.
- انتشار مقاله: 27-11-1396
- نویسندگان: Mehdi Najafi,Ramin Rafiee,Seyed Mohammad Esmaeil Jalali
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Mining and Geo-Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Graph theory,Open Pit,Dijkstra Algorithm,Optimization. Dynamic Programing
- چکیده:
- چکیده انگلیسی: In open-pit mine planning, the design of the most profitable ultimate pit limit is a prerequisite to developing a feasible mining sequence. Currently, the design of an ultimate pit is achieved through a computer program in most mining companies. The extraction of minerals in open mining methods needs a lot of capital investment, which may take several decades. Before the extraction, the pit limit, which influences the stripping ratio, damp locations, ore processing site and access routes, should be designed. So far, a large number of algorithms have been developed to optimize the pit limits. These algorithms are categorized into two groups: heuristic and rigorous. In this paper, a new approach is presented to optimize the pit limit based on Dijkstra’s algorithm which is based on mathematical relations. This algorithm was implemented on a 2D economic graph model and can find the true optimal solution. The results were compared with those from the dynamic programming (DP) algorithm. This algorithm showed to have less time complexity compared to the dynamic programming algorithm and to be easier to write dynamic computer programs.
- انتشار مقاله: 27-11-1396
- نویسندگان: Mehdi Najafi,Ramin Rafiee,Seyed Mohammad Esmaeil Jalali
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Hospital Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Coronary Artery Disease,patient safety,Patient outcome,CABG,Therapeutic Angiogenesis,Fibroblast Growth Factor,Patient management
- چکیده:
- چکیده انگلیسی: Background and Objectives: Complete revascularization is not possible in up to 37% of patients with coronary artery disease (CAD). Therapeutic angiogenesis may be considered as an option in the management of these patients. The aim of the present study was to evaluate the effectiveness and safety of therapeutic angiogenesis using basic fibroblast growth factor in patients with CAD.
Methods: In this double-blind, placebo-controlled study, eighteen patients with a severe diffuse atherosclerotic disease along the left anterior descending (LAD) artery who were a CABG candidate with at least one graftable coronary artery and the presence of ischemia and viable areas along the LAD were enrolled. The patients were randomized into two groups to either undergo CABG and simultaneous FGF-2 therapy (bFGF group) or CABG without FGF-2 therapy (control group). During the CABG procedure in bFGF group, FGF-2/alginate-heparin-sepharose microcapsules, each contains 100 mcg FGF-2, were implanted in the subepicardial layer of the diffusely defective LAD territory via 2-3 mm stab incisions. Seven patients in each group were followed up for a period of 24 months.
Findings: The result of left ventricular evaluation with echocardiography and perfusion scans showed significant improvement in FGF-2-receiving group with no significant change in controls, 3 and 6 months after the intervention. New Yor; Heart Association (NYHA) class was significantly lower in the intervention group (1.43±0.535 vs. 2.57±.535, P = 0.002), In addition, intervention group remained free of angina 24 months after the intervention while three patients in the control group were hospitalized due to the acute chest pain.
Conclusions: Our study revealed that FGF-2 can improve the outcomes of patients with CAD undergoing CABG, without serious adverse effects. Considering other advantages associated with protein therapy our finding may help open novel avenues to safe and cost-effective therapy of the target patients.- انتشار مقاله: 19-05-1395
- نویسندگان: Hossein Ahmadi,Armita Mahdavi,Morteza Daliri,Mohammad Imani,Abbasali Karimi Karimi,Abbas Salehi Omran,Mehdi Najafi,Mohsen Ahmadi,Farhad Fathi,Pegah Bikdeli,Payam Mohammadinejad
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Industrial Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Beam Angle Optimization,Fluence Map Optimization,Intensity Modulated Radiation Therapy,Treatment Programming
- چکیده:
- چکیده انگلیسی: Intensity modulated radiation therapy is one of the most commonly procedures used for delivering radiation to cancerous tissues. It aims to deliver the prescribed dose in the target volume while minimizing damage to the nearby healthy organs. In this procedure, two decisions being very important are selecting the beam angles and calculating the beam intensities. Although beam angle selection (beam angle optimization) is one of the most important decisions in this procedure, it is often be made manually and based on radio therapist experience and intuition. In order to overcome this drawback, this paper proposes a hybrid approach for automated beam angle selection and intensity computation. The proposed approach first finds a good feasible solution, and then use this solution as a starting point in local neighborhood search to find the local optimal solution. As the results of numerical experiments demonstrate, the proposed hybrid-approach, compared to its corresponding stand-alone methods, finds a better solution quickly and consistently.
- انتشار مقاله: 17-11-1395
- نویسندگان: Mehdi Najafi,Mahsa Faridmehr
- مشاهده