Quasiperiodic driving of Anderson localized waves in one dimension

Hatami, H.,Danieli, C.,Bodyfelt, J. D.,Flach, S. American Physical Society 2016 Physical Review E Vol.93 No.6

Effect of Co-Driver on Job Content and Depression of Truck Drivers

Hatami, Ali,Vosoughi, Shahram,Hosseini, Agha F.,Ebrahimi, Hossein Occupational Safety and Health Research Institute 2019 Safety and health at work Vol.10 No.1

Background: Since the presence of a co-driver can be considered as a companion, partner, or friend for a driver through eliminating driver's loneliness, it plays a significant role in health and safety of drivers. The objective of this study was to investigate the effect of co-drivers on depression and occupational stress on male truck drivers. Methods: This study was an interventional case-control study. Seventy truck drivers were selected and divided into two groups: case (33 truck drivers with co-drivers) and control (37 truck drivers without codrivers). Two Goldberg depression inventories (for evaluating driver's depression) and the Karasek job content questionnaire (for evaluating driver's job stress) were used to collect data which were completed by interview. Results: The results showed that job content values for the case group were higher in all dimensions except job nature. The comparison of the percentages showed significant difference between two groups. Depression rate in drivers with co-driver is truly less than depression rate in drivers without co-driver. There was significant positive relationship between dimensions of job content and depression rate. Conclusion: According to the results of this study, it can be claimed that a co-driver decreases stress and loneliness of drivers, as well as increases work performance and job satisfaction, and, in turn, leads to a decrease in job-related depression.

PRSV equation of state parameter modeling through artificial neural network and adaptive network-based fuzzy inference system

Tahmaseb Hatami,Masoud Rahimi,Hiua Daraei,Ehsan Heidaryan,Ammar Abdulaziz Alsairafi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.5

Two different modeling methods have been proposed to relate the Peng-Robinson-Stryjek-Vera (PRSV)parameter, κ1, to some common thermodynamic constants, including critical temperature (Tc), critical pressure (Pc),acentric factor (ω) and molecular weight (Mw). The methods are artificial neural network (ANN) and adaptive networkbased fuzzy inference System (ANFIS). A set of 159 data points (116, 23 and 20) was used for construct training, validating and testing, respectively. The radius parameter of ANFIS was determined through genetic algorithm (GA) optimization technique. The ANN and especially ANFIS results are in a good agreement with most of the compound groups.

Performance-based evaluation of strap-braced cold-formed steel frames using incremental dynamic analysis

S. Hatami,M.R. Davani,A. Zare 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.6

This study is an effort to clearly recognize the seismic damages occurred in strap-braced cold formed steel frames. In order to serve this purpose, a detailed investigation was conducted on 9 full scale strap-braced CFS walls and the required data were derived from the results of the experiments. As a consequence, quantitative and qualitative damage indices have been proposed in three seismic performance levels. Moreover, in order to assess seismic performance of the strap- braced CFS frames, a total of 8 models categorized into three types are utilized. Based on the experimental results, structural characteristics are calculated and all frames have been modeled as single degree of freedom systems. Incremental dynamic analysis using OPENSEES software is utilized to calculate seismic demand of the strap-braced CFS walls. Finally, fragility curves are calculated based on three damage limit states proposed by this paper. The results showed that the use of cladding and other elements, which contribute positively to the lateral stiffness and strength, increase the efficiency of strap-braced CFS walls in seismic events.

Stiffness of bi-modulus hexagonal and diamond honeycombs

Hamed Hatami-Marbini,Milad Rohanifar 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.4

Cellular materials are widely used in various applications because of their low density and high strength. The mechanical behavior of cellular materials under various loading conditions has been investigated. Nevertheless, many of these previous studies assume that the Young’s modulus of constituting struts is the same in tension and compression. The present work first derives analytical expressions for the effective Young’s moduli of hexagonal and diamond lattices composed of struts with different tension and compression moduli under the assumption of small strain deformation. It also uses the finite element method to further investigate the mechanical responses of these lattices. The macroscopic Young’s moduli under both compressive and tensile loads are reported as a function of the ratio of compression and tension moduli of constituting struts. The numerical finite element models are implemented by a user defined material subroutine in ABAQUS. Results reveal that the effective Young’s moduli of periodic hexagonal and diamond lattices significantly decrease with decreasing ratio of compression and tension moduli of the struts. Furthermore, the mechanical behavior of hexagonal lattices composed of struts with different tension–compression moduli is dependent on the loading direction and whether they are compressed or stretched. The unique mechanical properties of bi-modulus cellular materials could find important applications in the automotive and construction industries.

Effect of Co-Driver on Job Content and Depression of Truck Drivers

Ali Hatami,Shahram Vosoughi,Agha F. Hosseini,Hossein Ebrahimi 한국산업안전보건공단 산업안전보건연구원 2019 Safety and health at work Vol.10 No.1

Background: Since the presence of a co-driver can be considered as a companion, partner, or friend for a driver through eliminating driver’s loneliness, it plays a significant role in health and safety of drivers. The objective of this study was to investigate the effect of co-drivers on depression and occupational stress on male truck drivers. Methods: This study was an interventional case-control study. Seventy truck drivers were selected and divided into two groups: case (33 truck drivers with co-drivers) and control (37 truck drivers without codrivers). Two Goldberg depression inventories (for evaluating driver’s depression) and the Karasek job content questionnaire (for evaluating driver’s job stress) were used to collect data which were completed by interview. Results: The results showed that job content values for the case group were higher in all dimensions except job nature. The comparison of the percentages showed significant difference between two groups. Depression rate in drivers with co-driver is truly less than depression rate in drivers without co-driver. There was significant positive relationship between dimensions of job content and depression rate. Conclusion: According to the results of this study, it can be claimed that a co-driver decreases stress and loneliness of drivers, as well as increases work performance and job satisfaction, and, in turn, leads to a decrease in job-related depression.

Association Between the Risk of Multiple Sclerosis and Dietary Proinflammatory/Anti-Inflammatory Food Intake and Dietary Diversity: A Case-Control Study

Alireza Hatami,Maryam Ahmadi-khorram,Fatemeh Keykhaei,Ali Jafarzadeh Esfehani,Mohsen Nematy 한국임상영양학회 2024 Clinical Nutrition Research Vol.13 No.1

A diet rich in proinflammatory components and inflammation are suggested to be significant risk factors for multiple sclerosis (MS). This study aimed to investigate the association between the risk of MS and the inflammatory potential of an individual’s diet and dietary diversity through pro-inflammatory/anti-inflammatory food intake score (PAIFIS) and dietary diversity score (DDS). In a hospital-based case–control study, 397 participants, including 197 patients with MS and 200 healthy participants aged over 18 years, were evaluated. The history of smoking, dietary intake, and anthropometric characteristics, including body mass index, waist circumference, total body fat, and fat-free mass were assessed. A validated 160- item semiquantitative food frequency questionnaire was used to calculate the PAIFIS and DDS scores. The mean age of the participants was 32.45 ± 8.66 years, and most were females (274, 79.4%). The PAIFIS score was significantly higher among MS patients than healthy participants (p = 0.001). Between PAIFIS and DDS, only PAFIS was significantly related to MS risk (odds ratio, 1.002; 95% confidence interval, 1.001–1.004; p = 0.001). PAIFIS, as an index of dietary inflammation, can predict MS. Further studies are needed to document these findings.

Peroxisome Proliferator-Activated Receptor-γ Gene Expression and Its Association with Oxidative Stress in Patients with Metabolic Syndrome

Mehdi Hatami,Massoud Saidijam,Reza Yadegarzari,Shiva Borzuei,Alireza Soltanian,Marzieh Safi Arian,Mohammad Taghi Goodarzi 전남대학교 의과학연구소 2016 전남의대학술지 Vol.52 No.3

Regulation of the peroxisome proliferator-activated receptor-γ (PPAR-γ) gene plays an important role in controlling the metabolism of lipids and inflammatory processes. Therefore, it can be associated with the pathogenesis of metabolic syndrome (MetS). The purpose of this study was to determine the expression of this gene in peripheral blood mononuclear cells (PBMC) in patients with metabolic syndrome. Using real-time polymerase chain reaction (PCR), mRNA expression of PPAR-γ was found in PBMC from 37 subjects with MetS and 30 healthy controls. Serum levels of glucose and lipid profiles were measured. The total antioxidant capacity (TAC) was measured using the ferric reducing ability of plasma (FRAP) test. Malondialdehyde (MDA) was determined using a fluorimetric method. Total oxidant status (TOS) in serum was assayed according to oxidation of ferric to ferrous in the presence of methyl orange. Super oxide dismutase (SOD) activity was measured using a Randox kit. Expression of PPAR-γ gene was significantly increased in patients with MetS compared to the control subjects (p=0.002). There was no difference in serum levels of TAC, MDA and SOD between the two study groups, but a significant difference was observed in the TOS (p=0.03). Serum levels of triglycerides and glucose were significantly higher in subjects with MetS. According to the results of our study, an increase in the expression of PPAR-γ in subjects with MetS indicated a possible role of PPAR-γ in the pathogenesis of this disease.

Experimental and numerical investigations on the ratcheting characteristics of cylindrical shell under cyclic axial loading

Shariati, M.,Hatami, H.,Torabi, H.,Epakchi, H.R. Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.6

The ratcheting characteristics of cylindrical shell under cyclic axial loading are investigated. The specimens are subjected to stress-controlled cycling with non-zero mean stress, which causes the accumulation of plastic strain or ratcheting behavior in continuous cycles. Also, cylindrical shell shows softening behavior under symmetric axial strain-controlled loading and due to the localized buckling, which occurs in the compressive stress-strain curve of the shell; it has more residual plastic strain in comparison to the tensile stress-strain hysteresis curve. The numerical analysis was carried out by ABAQUS software using hardening models. The nonlinear isotropic/kinematic hardening model accurately simulates the ratcheting behavior of shell. Although hardening models are incapable of simulating the softening behavior of the shell, this model analyzes the softening behavior well. Moreover, the model calculates the residual plastic strain close to the experimental data. Experimental tests were performed using an INSTRON 8802 servo-hydraulic machine. Simulations show good agreement between numerical and experimental results. The results reveal that the rate of plastic strain accumulation increases for the first few cycles and then reduces in the subsequent cycles. This reduction is more rapid for numerical results in comparison to experiments.

Influence of interfacial adhesive on the failure mechanisms of truss core sandwich panels under in-plane compression

Mohammad J. Zarei,Shahabeddin Hatami,Mohammad Gholami 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.4

Sandwich structures with the superior mechanical properties such as high stiffness and strength-to-weight ratio, good thermal insulation, and high energy absorption capacity are used today in aerospace, automotive, marine, and civil engineering industries. These structures are composed of moderately stiff, thin face sheets that withstand the majority of transverse and in-plane loads, separated by a thick, lightweight core that resists shear forces. In this research, the finite element technique is used to simulate a sandwich panel with a truss core under axial compressive stress using ABAQUS software. A review of past experimental studies shows that the bondline between the core and face sheets plays a vital role in the critical failure load. Therefore, this modeling analyzes the damage initiation modes and debonding between face sheet and core by cohesive surface contact with traction-separation model. According to the results obtained from the modeling, it can be observed that the adhesive stiffness has a significant influence on the critical failure load of the specimens. To achieve the full strength of the structure as a continuum, a lower limit is obtained for the adhesive stiffness. By providing this limit stiffness between the core and the panel face sheets, sudden failure of the structure can be prevented.