Experimental and numerical analysis of aerodynamic effects of repair patches on damaged airfoils

Fakhri Etemadi,Mohammad Etemadi,Mahmoud Mani,Sina Pooladsanj 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

This investigation assesses the change of aerodynamic characteristics of triangular and star-shaped damaged airfoils with repair patches. Both experimental and numerical methods to determine aerodynamic coefficients are used in this study. The test model is a NACA 64 1 -412 airfoil full span, which is considered by using five schematics: Clean model, damaged model, upper repaired model, lower repaired model, and fully repaired model. Repair patches are chosen based on the Aircraft battle damage repair (ABDR) manuals. Various effects of repair schemes on triangular and star-shaped damages are quantitatively and qualitatively illustrated. A novel visualization method by paint and oil is used in wind tunnel tests to study the effects of repair patches on the damaged airfoil.

A Registry Program for Familial Gastric Cancer Patients Referred to Cancer Institute of Iran

Etemadi, Mehrnoosh,Pourian, Mandana,Shakib, Asyeh,Sabokbar, Tayebeh,Peyghanbari, Vahideh,Shirkoohi, Reza Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

Background: Gastric cancer is the second most common cause of cancer death. It has a poor prognosis with only 5-10% of hereditary etiology. If it is diagnosed, it could be helpful for screening the other susceptible members of a family for preventive procedures. Usually it is identified by symptoms such as presence of cancer in different members of family, some special type of pathology such as diffused adenocarcinoma, having younger age and multiple cancer syndromes. Hence, designing a registry program can be a more practical way to screen high risk families for a preventive program. Materials and Methods: Based on the inclusion criteria, a questionnaire was prepared. After pilot on a small number of patients, the actual data was collected from 197 patients and processed in SPSS 16.0. Results: Totally, 11.8% of the patients were younger than 45 years old. Blood type 'A' was dominant and males had a higher risk behavior with higher consumption of unhealthy food. Adenocarcinoma was reported in majority of cases. 21.8% of the patients had the including criteria for familial gastric cancer (FGC). Conclusions: The high percentage of FGC population compared to the other studies have revealed a need to design an infrastructural diagnostic protocol and screening program for patients with FGC, plus preventive program for family members at risk which could be done by a precise survey related to frequency and founder mutations of FGC in a national registry program.

Delay Tolerant Information Dissemination via Coded Cooperative Data Exchange

Shahriar Etemadi Tajbakhsh,Parastoo Sadeghi 한국통신학회 2015 Journal of communications and networks Vol.17 No.2

In this paper, we introduce a system and a set of algorithms for disseminating popular content to a large group of wireless clients spread over a wide area. This area is partitioned into multiple cells and there is a base station in each cell which is able to broadcast to the clients within its radio coverage. Dissemination of information in the proposed system is hybrid in nature: Each base station broadcasts a fraction of information in the form of random linear combinations of data blocks. Then the clients cooperate by exchanging packets to obtain their desired messages while they are moving arbitrarily over the area. In this paper, fundamental trade-offs between the average information delivery completion time at the clients and different parameters of the system such as bandwidth usage by the base stations, average energy consumption by the clients and the popularity of the spread information are studied. Moreover different heuristic algorithms are proposed to control and maintain a balance over these trade-offs. Also, the more complicated case of multiple sessions where each client is interested in an arbitrary subset of sessions is considered and two variants of the basic dissemination algorithm are proposed. The performance of all the proposed algorithms is evaluated via extensive numerical experiments.

On the Hybrid Modeling of Phenomenological Damage Evolution in Low Carbon Steels During Equal Channel Angular Extrusion Process

M. Etemadi,Ali M. Rashidi,A. Zajkani 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.5

Low carbon steel is widely used in industry due to its excellent elastoplastic behavior with the mechanism of damage accumulationduring severe plastic deformation processes which lead to increase strength resistance. In this study, the strain locus ofthe failure is predicted based on the stress triaxiality and Lode angle-dependent damage model by considering damage evolutionduring the process. Therefore, by performing various tests for several stress states and modeling the load paths related todamage accumulations, the coefficients of the modified Mohr–Coulomb damage model and Johnson–Cook are determined. According to results achieved among the test with good accuracy, the predictor locus of the failure strain is illustrated. Then,using the determined coefficients, the steel damage evolution is investigated during the process of Equal Channel AngularExtrusion (ECAE). It is shown that the damage accumulation during the ECAE process in a die with respectively internaland external angles of 90 and 30 degrees grows from the region closer to the internal angle as reaches a maximum value incentral regions. Also, the amount of damage in vicinity of the outer angle is extremely reduced. According to experiments,the steel does resist fracture events after the ECAE process.

Coordination of a Group of Autonomous Agents with Limited Field of View through Variable Structure Control Method

S. Etemadi,H. Kouhi,A. Alasty,G.R. Vossoughi 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this paper behavioral control of autonomous agents of a multi-agent system is considered. In previous paper authors presented a nonlinear approach for coordination of a group of autonomous agents by an active leader. The leader and other agents are assumed to possess limited field of view. The leader agent is able to lead the multi-agent system toward its destination only if all agents expose a quasi-static behavior. Agents as autonomous members may have higher equations of motion which can violate coordination control algorithm of the multi-agent system. To force every agent to behave as a member with quasi-static equation of motion we have designed a behavioral controller in this paper. The behavioral controller uses the local information for every agent and produces the control signal. It is based on the Sliding-mode control method so that the effect of bounded disturbances and uncertainties can be omitted as well. Once autonomous agents are equipped with the behavioral controller, the multi-agent system behaves similar to a group of agents with quasi-static behaviors and the coordination control algorithm is useable for the group.

Evaluation of Visual Quality of Bermudagrass (Cynodon dactylon L.) Population

Nematollah Etemadi,Zabiollah Zamani,Khorshid Razmjoo 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Real-time Velocity Optimization of a Group of Autonomous Members via Ant Colony Optimization (ACO)

Ramin Vatankhah,Shahram Etemadi,Aria Alasty,Mehrdad Boroushaki,Gholamreza Vossoughi 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this paper, the agent velocity in robotic swarm was determined by using Ant Colony optimization (ACO) algorithm to maximize the swarm center velocity. First briefly we present an analytical study of swarm motion in a quasi static environment, in which, motion of each member is being affected by interactive forces and an agent. Interactive effects on each member could be attractive or repulsive due to being far from or close to other members respectively. It is also considered that field of view of all members is limited, i.e. even the agent accesses its local information. Ant colony algorithm is a mathematical model of ants" behaviour in finding the shortest path between nest and food. The agent velocity in robotic swarm was determined by using ACO to maximize the swarm center velocity. The results show the high ability of this evolutionary algorithm in solving complicated dynamic optimization problems.

Effect of Light Intensity on Leaf Morphology, Photosynthetic Capacity, and Chlorophyll Content in Sage (Salvia officinalis L.)

Sedigheh Rezai,Nematollah Etemadi 한국원예학회 2018 원예과학기술지 Vol.36 No.1

Sage (Salvia officinalis) has been an important medicinal plant since antiquity. Here, we aimed todetermine the optimum light intensity for S. officinalis growth by quantifying the effects of differentshade treatments on plant morphology, chlorophyll and carotenoid content, and photosyntheticcapacity in a semi-arid region of Iran. Plants were grown for 5 months under full sunlight (0%shade) as well as 30%, 50%, or 70% shade levels by applying different shade treatments. While leafsize was greatest under 50% shade level, leaves of seedlings grown under full sunlight weresmallest. Leaf color under both 50% and 70% shade levels was yellowish-green. The highestphotosynthesis activity was achieved under full sunlight. Decreasing light intensity led to anincrease in chlorophyll and carotenoid content. Shade levels above 30% limited carbon assimilationand led to decreased essential oil content and plant growth. In conclusion, 30% shade is suggestedto be an optimum light irradiance for the cultivation of S. officinalis.

A Novel PCR Assay for Detecting Brucella abortus and Brucella melitensis

Saeed Alamian,Majid Esmaelizad,Taghi Zahraei,Afshar Etemadi,Mohsen Mohammadi,Davoud Afshar,Soheila Ghaderi 질병관리본부 2017 Osong Public Health and Research Persptectives Vol.8 No.1

Objectives: Brucellosis is a major zoonotic disease that poses a significant public health threat worldwide. The classical bacteriological detection process used to identify Brucella spp. is difficult and time-consuming. This study aimed to develop a novel molecular assay for detecting brucellosis. Methods: All complete sequences of chromosome 1 with 2.1-Mbp lengths were compared among all available Brucella sequences. A unique repeat sequence (URS) locus on chromosome 1 could differentiate Brucella abortus from Brucella melitensis. A primer set was designed to flank the unique locus. A total of 136 lymph nodes and blood samples were evaluated and classified by the URS-polymerase chain reaction (PCR) method in 2013–2014. Results: Biochemical tests and bacteriophage typing as the golden standard indicated that all Brucella spp. isolates were B. melitensis biovar 1 and B. abortus biovar 3. The PCR results were the same as the bacteriological method for detecting Brucella spp. The sensitivity and specificity of the URS-PCR method make it suitable for detecting B. abortus and B. melitensis. Conclusion: Quick detection of B. abortus and B. melitensis can provide the most effective strategies for control of these bacteria. The advantage of this method over other presented methods is that both B. abortus and B. melitensis are detectable in a single test tube. Furthermore, this method covered 100% of all B. melitensis and B. abortus biotypes. The development of this URS-PCR method is the first step toward the development of a novel kit for the molecular identification of B. abortus and B. melitensis.

Comparison of Inhibitory Effect of 17-DMAG Nanoparticles and Free 17-DMAG in HSP90 Gene Expression in Lung Cancer

Mellatyar, Hassan,Akbarzadeh, Abolfazl,Rahmati, Mohammad,Ghalhar, Masoud Gandomkar,Etemadi, Ali,Nejati-Koshki, Kazem,Zarghami, Nosratallah,Barkhordari, Amin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

Background: Up-regulation of hsp90 gene expression occurs in numerous cancers such as lung cancer. D,L-lactic-co-glycolic acid-poly ethylene glycol-17-dimethylaminoethylamino-17-demethoxy geldanamycin (PLGA-PEG-17DMAG) complexes and free 17-DMAG may inhibit the expression. The purpose of this study was to examine whether nanocapsulating 17DMAG improves the anti cancer effect over free 17DMAG in the A549 lung cancer cell line. Materials and Methods: Cells were grown in RPMI 1640 supplemented with 10% FBS. Capsulation of 17DMAG is conducted through double emulsion, then the amount of loaded drug was calculated. Other properties of this copolymer were characterized by Fourier transform infrared spectroscopy and H nuclear magnetic resonance spectroscopy. Assessment of drug cytotoxicity on the grown of lung cancer cell line was carried out through MTT assay. After treatment, RNA was extracted and cDNA was synthesized. In order to assess the amount of hsp90 gene expression, real-time PCR was performed. Results: In regard to the amount of the drug load, IC50 was significant decreased in nanocapsulated(NC) 17DMAG in comparison with free 17DMAG. This was confirmed through decrease of HSP90 gene expression by real-time PCR. Conclusions: The results demonstrated that PLGA-PEG-17DMAG complexes can be more effective than free 17DMAG in down-regulating of hsp90 expression by enhancing uptake by cells. Therefore, PLGA-PEG could be a superior carrier for this kind of hydrophobic agent.