NUMERICAL STUDY OF TURBULENCE DYNAMICS IN PLUNGING & SURGING BREAKING WAVES

KHAYYER ABBAS,YEGANEH-BAKHTIARY ABBAS,GHAHERI ABBAS,GOTOH HITOSHI,SAKAI TETSUO 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

Bimetal cup hydroforming of Al/St and Cu/St composites: Adaptive finite element analysis and experimental study

Abbas Hashemi,Mohammad Hoseinpour Gollo,S. M. Hossein Seyedkashi 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5

An adaptive Finite element analysis (FEA) was proposed in this paper for the industrial design of bimetal conical-cylindrical cup hydroforming. Forming circumstances for the perfect and imperfect parts were concluded through adaptive FEA using the ANSYS parametric design language. Effective parameters, including pressure loading path, layer placement order, and thickness ratio, were investigated for hydroforming of Al/St and Cu/St composite sheets. Experimental tests were implemented to validate adaptive finite element results. Rupture failure upon the pressure path occurred on the contact area between the blank and punch tip radius at low pressures and on the transition area of the conical-cylindrical portion at high pressures. The proposed method is applicable for any cylindrical, conical, or cylindrical/conical shapes with different materials and dimensions. Therefore, this method is beneficial as a practical design tool for engineers and researchers working in the process design of hydroformed shell products.

The Impact of China Exchange Rate Policy on its Trading Partners: Evidence Based on the GVAR Model

ABBAS, Shah,NGUYEN, Van Chien,YANFU, Zhu,NGUYEN, Huu Tinh Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8

This study is designed to investigate the impact of China exchange rate policy on its trading partners by using a country multi-dataset GVAR model. Our model includes samples of 30 countries, six from high-income, six from middle-income and eighteen from low-income countries. This study used annual time series data over the period 1992 to 2017. We constructed currency misalignment index and it provided some interesting features about the currency undervaluation and overvaluation. The results of the currency misalignment shows that China's Renminbi is structurally more undervalued over the sample period as compared to other countries, and fluctuation in major currencies effects the global trade around the world. The overall empirical results of the GVAR model indicate that RMB undervaluation affects the trade pattern and macroeconomic performance of China's trading partners. Overall, China's exchange rate undervaluation has mixed effects on trading partner's GDP, exports and imports. The devaluation of China's RMB efficiently stimulated China's exports and reduced imports. While, in some countries, this effect is reverse, the RMB undervaluation increases the GDP of partner countries and also increases their exports to China. The results confirm the strong and leading role of the Chinese Renminbi in the global trade.

Frequencies of CD4+ T Regulatory Cells and their CD25high and FoxP3high Subsets Augment in Peripheral Blood of Patients with Acute and Chronic Brucellosis

Abbas Bahador,Jamshid Hadjati,Niloofar Hassannejad,Hadi Ghazanfari,Mohammadreza Maracy,Sirous Jafari,Maryam Nourizadeh,Amirhooshang Nejadeh 질병관리본부 2014 Osong Public Health and Research Persptectives Vol.5 No.3

Objectives: Brucellosis remains one of the most common zoonotic diseases worldwide. In humans, brucellosis can be a serious, debilitating, and sometimes chronic disease. Different mechanisms can be postulated as to the basis for the induction of the chronic status of infectious diseases that T regulatory cells are one of the most important related mechanisms. The current study was designed to determine whether percentage of CD4+Treg cells and their CD25high and FoxP3high subpopulations in peripheral blood are changed in human brucellosis samples in comparison to a control group. Methods: In total, 68 brucellosis patients (acute form: n Z 43, chronic form: nZ25) and 36 healthy volunteers entered our study. After isolating of peripheral blood mononuclear cells, heparinized venous blood samples were obtained from both patients and healthy donors, CD4, CD25, and FoxP3 molecules were evaluated by two- and three-color flow cytometric methods. Results: The results revealed a new finding in relation to Treg cells and human brucellosis. The numbers of CD4+Treg cells and their CD25high and FoxP3high subsets increase significantly in the peripheral blood of acute and chronic forms of brucellosis samples compared with healthy groups, with this increase being greater in the chronic group. Conclusion: There seems to be a correlation between increase of CD4+Treg cells and their subsets and the disease progress from healthy state to acute and chronic brucellosis.

TEM and SHV Genes in Klebsiella pneumoniae Isolated from Cockroaches and Their Antimicrobial Resistance Pattern

Abbas Doosti,Mohammad Pourabbas,Asghar Arshi,Mohammad Chehelgerdi,Hamidreza Kabiri 질병관리본부 2015 Osong Public Health and Research Persptectives Vol.6 No.1

Objectives: Klebsiella pneumoniae is a gram-negative rod bacterium, a known cause of community-acquired bacterial pneumonia and is an important hospitalacquired pathogen that causes severe morbidity and mortality. The aim of this study was to identify the TEM and SHV genes in K. pneumoniae isolated from cockroaches obtained from hospitals. Methods: In this study, 250 cockroaches were collected from different hospitals in the province of Chaharmahal Va Bakhtiari, which is located in southwest Iran. The samples were examined for the presence of K. pneumoniae by plating onto a combination of culture media, and the antimicrobial susceptibility patterns of isolated K. pneumoniae from samples were evaluated using the disk diffusion test. In addition, from the culture, genomic bacterial DNA was extracted, and sequence-specific targets (TEM and SHV genes) were amplified using the polymerase chain reaction (PCR) method. Results: Out of 250 cockroach samples collected from various hospitals, 179 samples (71.60%) were positive for K. pneumoniae. PCR reaction was performed using specific oligonucleotide primers (TEM-F, TEM-R and SHV-F, SHV-R) for the amplification of each gene, and amplified products were visualized on 1% agarose gel electrophoresis. Of all the specimens amplified by PCR in this research, 32 samples (17.87%) were positive for TEM and 15 samples (8.37%) were positive for SHV. Conclusion: Detection of TEM and SHV genes using molecular methods and their pattern of antimicrobial resistance can provide useful information about the epidemiology of and risk factors associated with K. pneumoniae infection.

An Analogy between Various Machine-learning Techniques for Detecting Construction Materials in Digital Images

Abbas Rashidi,Mohamad Hoseyn Sigari,Marcel Maghiar,David Citrin 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.4

Digital images and video clips collected at construction jobsites are commonly used for extracting useful information. Exploring new applications for image processing techniques within the area of construction engineering and management is a steady growing field of research. One of the initial steps for various image processing applications is automatically detecting various types of construction materials on construction images. In this paper, the authors conducted a comparison study to evaluate the performance of different machine learning techniques for detection of three common categorists of building materials: Concrete, red brick, and OSB boards. The employed classifiers in this research are: Multilayer Perceptron (MLP), Radial Basis Function (RBF), and Support Vector Machine (SVM). To achieve this goal, the feature vectors extracted from image blocks are classified to perform a comparison between the efficiency of these methods for building material detection. The results indicate that for all three types of materials, SVM outperformed the other two techniques in terms of accurately detecting the material textures in images. The results also reveals that the common material detection algorithms perform very well in cases of detecting materials with distinct color and appearance (e.g., red brick); while their performance for detecting materials with color and texture variance (e.g., concrete) as well as materials containing similar color and appearance properties with other elements of the scene (e.g., ORB boards) might be less accurate.

Aerodynamic shape study of supersonic surface to surface missiles with continuous flexible nose

Abbas Khalghani,Mahmoud Pasandideh-Fard,Mohamad Hasan Djavareshkian 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

The aerodynamic characteristics of nine configurations of supersonic continuous deflectable nose guided missiles have been investigated. The optimized geometry was achieved based on the accuracy of confliction with constant target in ground to ground mission. The studied configurations consist of a spherical nose tip, a tangent ogive, one set of stabilizing tail fines and a cylindrical body whose midsection is flexible to form an arc of a circle. So the cylindrical body consists of a fixed part in the vicinity of the nose, middle flexible part and main body with stabilizers. The effects of fixed length (Fix = 0, 1.5, 3Cal) and flexible length (Flex = 1, 2.5, 5Cal) parameters on the aerodynamics and flight dynamics of guided missile have been studied. A code has been developed to solve full Navier-Stokes equations using finite volume and Runge-Kutta time stepping techniques and modified Baldwin-Lomax turbulence model. Multi-block technique was also used to solve the main body and fin parts flow fields. Further, a 3 degree of freedom code along with a pure pursuit guidance subroutine was developed to compare planar flight dynamics of missiles. It was found that although the missiles with bigger lengths for fixed and flex parts show more maneuverability, but this is not favorable for all missile missions as sometimes it decreases the confliction accuracy. Flight dynamic analysis shows that a change in initial launch angle may shift the favorite configuration. This means only the aerodynamic defined aim functions cannot completely supersede flight dynamic analysis in geometric optimization. Further, the thrust vector moment is an important portion of total control moment as it enhances the hitting accuracy and also decreases the importance of geometry.

High Prevalence of AmpC β-Lactamases in Clinical Isolates of Escherichia coli in Ilam, Iran

Abbas Maleki,Afra Khosravi,Sobhan Ghafourian,Iraj Pakzad,Shiva Hosseini,Rashid Ramazanzadeh,Nourkhoda Sadeghifard 질병관리본부 2015 Osong Public Health and Research Persptectives Vol.6 No.3

Objectives: Widespread use of β-lactam antibiotics could cause resistance to this group of antibiotics in pathogenic bacteria through the production of the enzyme β-lactamases. The aimof this study is to determine themolecular detection of AmpC β-lactamases among clinical Escherichia coli isolated from Ilam hospitals in Ilam, Iran. Methods: One hundred and twelve clinical isolates of E. coli were collected from hospitalized patients and were identified by biochemical tests. They were evaluated for extended spectrum beta-lactamases (ESBLs) production, and the positive strains were subjected to AmpC enzymes; for detection of AmpC cluster genes, multiplex polymerase chain reaction was applied. Results: The analysis showed 62.5% of isolates were ESBLs positive and that five strains revealed the AmpC cluster genes. This is the first report of FOXM cluster genes in E. coli in Iran. Conclusion: Based on our results, the prevalence of AmpC β-lactamases is increasing in Iran, which caused failure in antibiotic therapy. So, the current study recommended the revision of antibiotic policy in Iranian hospitals.

Position of the hyoid bone and its correlation with airway dimensions in different classes of skeletal malocclusion using cone-beam computed tomography

Abbas Shokri,Vahid Mollabashi,Foozie Zahedi,Leili Tapak 대한영상치의학회 2020 Imaging Science in Dentistry Vol.50 No.2

Purpose: This study investigated the position of the hyoid bone and its relationship with airway dimensions in different skeletal malocclusion classes using cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans of 180 participants were categorized based on the A point-nasion-B point angle into class I, class II, and class III malocclusions. Eight linear and 2 angular hyoid parameters (H-C3, H-EB, H-PNS, H-Me, H-X, H-Y, H-[C3-Me], C3-Me, H-S-Ba, and H-N-S) were measured. A 3-dimensional airway model was designed to measure the minimum cross-sectional area, volume, and total and upper airway length. The mean crosssectional area, morphology, and location of the airway were also evaluated. Data were analyzed using analysis of variance and the Pearson correlation test, with P values <0.05 indicating statistical significance. Results: The mean airway volume differed significantly among the malocclusion classes (P<0.05). The smallest and largest volumes were noted in class II (2107.8±844.7 mm3) and class III (2826.6±2505.3 mm3), respectively. The means of most hyoid parameters (C3-Me, C3-H, H-Eb, H-Me, H-S-Ba, H-N-S, and H-PNS) differed significantly among the malocclusion classes. In all classes, H-Eb was correlated with the minimum cross-sectional area and airway morphology, and H-PNS was correlated with total airway length. A significant correlation was also noted between H-Y and total airway length in class II and III malocclusions and between H-Y and upper airway length in class I malocclusions. Conclusion: The position of the hyoid bone was associated with airway dimensions and should be considered during orthognathic surgery due to the risk of airway obstruction.

Revenue Maximization in Scheduling of Electric Vehicles Considering the Capacity of Parking Lots

Abbas Mehrabi,Hyoyoung Jung,Saransh Malik,Kiseon Kim 한국통신학회 2016 한국통신학회 학술대회논문집 Vol.2016 No.1