• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10603-10605
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• 2015

Background: The Prostate cancer is the 2nd most common cancer worldwide for males, and the 5th most common cancer overall, with an estimated 900,000 new cases diagnosed in 2008 (14% of the total in males and 7% of the total overall) aim of this study was to assess some of the most proposed environmental factors influencing the incidence of prostate cancer among Iranian men. Smoking, opioids, occupation and living location were considered as studied risk factors of the prostate cancer in this research. Material and methods: Two groups of affected men with prostate cancer and controls aged 50-75 years referred to medical clinics were subjects in this case-control study. Living and working place, smoking and drug consuming habits were assessed for any associations with prostate cancer. Results: The largest number, of patients, in order, belonged to Tehran, provincial capitals, major industrial cities, small towns and villages, respectively. The disease showed links with smoking and drugs with a significant difference between controls and patients (P value <0.0001). Conclusions: Our recent evidence duplicates previously done researches confirming the serious adverse effects of smoking and drugs on the prostate cancer occurrence in Iranian men. Living place bearings some hazardous behaviors which increases the rate of diseases as well as advanced chance for associated cancers like prostate.

• Tribology and Lubricants
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• v.37 no.6
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• pp.261-272
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• 2021

This study investigates the structural characteristics of oil-free, gas beam foil journal bearings (GBFJBs) for use in high speed motors. Mathematical modeling was carried out, and reaction force modeling for static load was performed to predict the structural characteristics of the GBFJB. Mathematical modeling and reaction force modeling for static load are performed to predict the structural characteristics of GBFJBs. The reaction force of the test bearing against static loads was measured during experiments and compared with the predicted results. The measured experimental data reveal the nonlinear stiffness characteristics of the GBFJB against varying displacement and agree well with the predictions. Dynamic load tests using an exciter allow to identify the vibration characteristics of the GBFJB. Test results show that the vibration displacement, dynamic force, and acceleration measured on the test bearing are most dominant at the applied dynamic load (synchronization) frequency. Futhermore, the test results show that the hysteresis area recorded during the dynamic tests increases with the excitation amplitude and frequency, and that the beam stick phenomena occurr at high excitation frequencies. The single degree of freedom (DOF) vibration model aids to identify the stiffness and damping coefficient of the GBFJB, which decrease as the excitation frequency increases.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.295-306
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• 2005

In this study, the dynamic characteristics of the two open-steel-plate-girder bridges was analyzed using the pads' stiffness estimated in the previous accompanying paper.Also, it was determined that the variation in the dynamic behavior of the two bridges due to the pads corresponds to the codes describing the restriction for the steel bridges' behavior.The pads installed at the bridges increase the displacement at mid-span.However, the increase does not exceed code restrictions and does not have an adverse effect on the riding quality of the running trains. The natural and Chloroprene rubber pads are not suitable for bridge bearings since they are more deformed than the code regulated ones.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.307-316
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• 2005

This study analyzed the characteristics of four kinds of bridge rubber pads and suggested a method of determining the stiffness and the damping ratio of the pads.The stiffness of rubber pads can be estimated by a direct static test and a dynamic test indirectly.This study used both methods to determine the pad's stiffness.The damping ratio of pads can be obtained using the dynamic test and the damping ratio of polyurethane rubber pads was estimated to aproximate that of natural and chloroprene rubber pads.The polyurethane rubber pads are harder than natural and chloroprene rubber pads and thus carry larger load bearing capacity.In addition, they showed higher stiffness with the same shape factor than the others and thus are more available for bridge bearings.Although natural and chloroprene rubber pads are elongated to large deformation in the horizontal direction due to vertical loads, polyurethane rubber pads almost do not generate horizontal deformation due to vertical loads regardless of the thickness and hardness of the pads.Therefore, they do not need reinforced plate to restrict horizontal deformation.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.47-56
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• 2006

A method is presented for evaluating the economic efficiency of a semi-active magneto-rheological (MR) damper system for cable-stayed bridges under earthquake loadings. An optimal MR damper capacity maximizing the cost-effectiveness is estimated for various seismic characteristics of ground motion. The economic efficiency of MR damper system is addressed by introducing the life-cycle cost concept. To evaluate the expected damage cost, the probability of failure is estimated. The cost-effectiveness index is defined as the ratio of the sums of the expected damage costs and each device cost between a bridge structure with the MR damper system and a bridge structure with elastic bearings. In the evaluation of cost-effectiveness, the scale of damage cost is adopted as parametric variables. The results of the evaluation show that the MR damper system can be a cost-effective design alternative. The optical capacity of MR damper is increased as the seismic hazard becomes severe.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.2
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• pp.131-138
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• 2013

The high damping rubber bearings contributed to reduce a seismic force transmitted to upper structures, the material properties of rubber changes with time and the rubber with age-related degradation can affect the seismic response of structures and equipments. Therefore the seismic response of structure considering age-related degradation of isolators should be evaluated. In this paper, the stiffness and damping for isolators were defined using the aging data proposed by other researchers. The reactor containment building and the auxiliary building were selected to conduct the nonlinear analysis and the natural frequency, maximum responses, floor response spectrum(FRS) were evaluated with time using the four earthquakes with different frequency contents. According to the analysis results, the seismic responses are increased by the age-related degradation of isolators and the detail inspections should be conducted up to 20 years because it was presented that the change of FRS was high during this period.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.29-38
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• 1994

Linear composite theory as well as a finite element program is developed for axisymmetric elastomeric bearings. This study is limited to axisymmetrically loaded horizontal layered systems with linear, elastic, small' deformation conditions. A multiscale method is used in the development of the composite theory which enables us to model inhomogeneous layered composites as equivalent homogeneous, orthotropic material. Only continuity of the prime variables is required for the finite element analysis, allowing the use of simple $C_o$ elements whereas rather complicated theories presented in the past need more requirements. Four node isoparametric elements are used in the study. The developed theory of this paper is limited to linear conditions, however, the analysis can be extended to nonlinear behavior of flexible material in elastomeric bearing by using multiscale method presented here. Two numerical examples are examined and compared to the results of discrete and previously obtained composite analysis to verify the theory.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.5 s.51
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• pp.11-23
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• 2006

This paper evaluates the seismic response of multi-span prestressed concrete girder bridges typically found in the New Madrid Seismic Zone region of the central United States. Using detailed nonlinear analytical models and synthetic ground motion records for Memphis, TN, nonlinear response history analyses are performed for two levels of ground motion: 10% probability of exceedance (PE) in 50 years, and 2% probability of exceedance (PE) in 50 years. The results show that the bridge performance is very good fur the 10% PE in 50 years ground motion level. However, the performance for the 2% PE in 50 years ground motion is not so good because it results in highly inelastic behavior of the bridge. Impact between decks results in large ductility demands on the columns, and failure of the bearings that support the girders. It is found that making the superstructure continuous, which is commonly performed for reducing dead load moments and maintenance requirements, results in significant improvement in the seismic response of prestressed concrete girder bridges.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.5 s.39
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• pp.79-89
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• 2004

This paper presents the results of experimental studies on the equipment isolation effect in the nuclear containment. For this purpose, shaking table tests were performed. The purpose of this study is enhancement of seismic safety of equipment in the Nuclear Power Plant. The isolation system, known as Friction Pendulum System (FPS), combines the concepts of sliding bearings and pendulum motion was selected. Peak ground acceleration, bidirectional motion, effect of vertical motion and frequency contents of selected earthquake motions were considered. As a result, these are founded that the vertical motion of seismic wave affect to the base isolation and the isolation effect decreased in case of near fault earthquake motion.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.4
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• pp.300-307
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• 2016

The faults in railway vehicle components may result in either the stoppage of the service and the derailment of the vehicle. Therefore, it is important to diagnose and monitor the main components of a railway vehicle. The use of temperature is one of the basic methods for the diagnosis of abnormal conditions in the rotational components of a railway vehicle, such as bearings, reduction gears, brake discs, wheels and traction motors. In the present study, the diagnose of the rotational components using infrared thermography and a pattern recognition technique was carried out and a field test was performed. The results show that this method of diagnosis using infrared thermography can be used to identify abnormal conditions in rotational components of a railway vehicle.