http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Shahrokh, Ayda (검색결과 71 건)
- 무료
- 기관 내 무료
- 유료
-
Shahrokh Maalek,Hamid Heidary-Torkamani,Moharram Dolatshahi Pirooz,Seyed Taghi Omid Naeeini 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.3
In this research, the behavior of tube-in-tube BRBs (TiTBRBs) has been investigated. In a typical TiTBRB, the yielding core tube is located inside the outer restraining one to dissipate energy through extensive plastic deformation, while the outer restraining tube remains essentially elastic. With the aid of FE analyses, the monotonic and cyclic behavior of the proposed TiTBRBs have been studied as individual brace elements. Subsequently, a detailed finite element model of a representative single span-single story frame equipped with such a TiTBRB has been constructed and both monotonic and cyclic behavior of the proposed TiTBRBs have been explored under the application of the AISC loading protocol at the braced frame level. With the aid of backbone curves derived from the FE analyses, a simplified frame model has been developed and verified through comparison with the results of the detailed FE model. It has been shown that, the simplified model is capable of predicting closely the cyclic behavior of the TiTBRB frame and hence can be used for design purposes. Considering type of connection detail used in a frame, the TiTBRB member which behave satisfactorily at the brace element level under cyclic loading conditions, may suffer global buckling due to the flexural demand exerted from the frame to the brace member at its ends. The proposed TiTBRB suit tubular members of offshore structures and the application of such TiTBRB in a typical offshore platform has been introduced and studied in a single frame level using detailed FE model.
-
-
Three dimensional dynamic response of functionally graded nanoplates under a moving load
Shahrokh Hosseini-Hashemi,Hossein Bakhshi Khaniki 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.2
In this paper, reaction of functionally graded (FG) thick nanoplates resting on a viscoelastic foundation to a moving nanoparticle/load is investigated. Nanoplate is assumed to be thick by using second order shear deformation theory and small-scale effects are taken into account in the framework of Eringen’s nonlocal theory. Material properties are varied through the thickness using FG models by having power-law, sigmoid and exponential functions for material changes. FG nanoplate is assumed to be on a viscoelastic medium which is modeled using Kelvin-Voight viscoelastic model. Galerkin, state space and fourth-order Runge-Kutta methods are employed to solve the governing equations. A comprehensive parametric study is presetned to show the influence of different parameters on mechanical behavior of the system. It is shown that material variation in conjunction with nonlocal term have a significant effect on the dynamic deformation of nanoplate which could be used in comprehending and designing more efficient nanostructures. Moreover, it is shown that having a viscoelastic medium could play an important role in decreasing these dynamic deformations. With respect to the fresh studies on moving atoms, molecules, cells, nanocars, nanotrims and point loads on different nanosctructures using scanning tunneling microscopes (STM) and atomic force microscopes (AFM), this study could be a step forward in understanding, predicting and controlling such kind of behaviors by showing the influence of the moving path, velocity etc. on dynamic reaction of the plate.
-
( Shahrokh Ezzatzadegan Jahromi ),( Ghasem Haghighi ),( Jamshid Roozbeh ),( Vahid Ebrahimi ) 대한신장학회 2019 Kidney Research and Clinical Practice Vol.38 No.2
Background: Automated office blood pressure (AOBP) machines measure blood pressure (BP) multiple times over a brief period. We aimed to compare the results of manual office blood pressure (MOBP) and AOBP methods with ambulatory BP monitoring (ABPM) in patients with chronic kidney disease (CKD). Methods: This study was performed on 64 patients with CKD (stages 3-4). A nurse manually measured the BP on both arms using a mercury sphygmomanometer, followed by AOBP of the arm with the higher BP and then ABPM. Mean BP readings were compared by paired t test and Bland-Altman graphs. Results: The mean ± standard deviation (SD) age of participants was 59.3 ± 13.6. The mean ± SD awake systolic BP obtained by ABPM was 140.2 ± 19.0 mmHg, which was lower than the MOBP and AOBP methods (156.6 ± 17.8 and 148.8 ± 18.6 mmHg, respectively; P < 0.001). The mean ± SD awake diastolic BP was 78.6 ± 13.2 mmHg by ABPM which was lower than the MOBP and AOBP methods (88.9 ± 13.2 and 84.1 ± 14.0 mmHg, respectively; P < 0.001). Using Bland-Altman graphs, MOBP systolic BP readings showed a bias of 16.4 mmHg, while AOBP measurements indicated a bias of 8.6 mmHg compared with ABPM. Conclusion: AOBP methods may be more reliable than MOBP methods for determining BP in patients with CKD. However, the significantly higher mean BPs recorded by AOBP method suggested that AOBPs may not be as accurate as ABPM in patients with CKD.
-
The Effects of Rest Problems on Workforce Fatigue and Productivity
Shahrokh Shahraki,Nooh Bin Abu Bakar 대한산업공학회 2019 Industrial Engineeering & Management Systems Vol.18 No.4
This study examines the impact of rest problems on workforce fatigue and productivity. The participants of the studyinclude 4188 employees working at four Malaysian corporations. First, they were surveyed about rest time patternsand then, they completed the Work Limitations Questionnaire. Next, the respondents were classified into four groups:insomnia (Level-1), insufficient rest (Level-2), at-risk (Level-3), and good rest (Level-4). The costs related to productivity were estimated through the Work Limitations Questionnaire. Performance, productivity, safety, and treatmentmeasures were compared using the one-way analysis of variance model. The findings showed that level-1 and level-2groups caused higher negative effects than level-3 and level-4 groups, on productivity, performance, and safety. Thelevel-1 group had the highest rate of rest medication use. The other groups were more likely to use no medicationtreatments. Fatigue-related productivity losses were estimated to cost $1967/workforce annually. However, rest problems contribute to decreasing workforce productivity leading to a high cost to companies.
-
Shahrokh Rahmani,Mansour Alizadeh,Pedram Tehrani,Mahdi Navidbakhsh 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.8
AVICENA is a new cardiac assist device which helps the patients suffering from left ventricular failure. This study aims to investigate the performance of this device and its effect on the aortic valve within different patterns of inflation and deflation of the balloon. Twelve different displacement factor curves which are applied to the balloon part of AVICENA and required for the performing of balloon inflation and deflation are selected and examined in three cases named low-pressure, normal-pressure, and high-pressure subjects. The results of generated energy, aortic valve force and pressure required for the balloon’s inflation and deflation are presented within a heart cycle. The outcomes of the present study can be utilized in designing of the AVICENA with more power generation and less aortic valve force for different subjects.
-
Iravani, Shahrokh,Kashfi, Seyed Mohammad Hossein,Azimzadeh, Pedram,Lashkari, Mohammad Hossein Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22
Background: Colorectal cancer is the third most common type of cancer in males and the second in females in Iran. Males are more likely to develop CRC than women and age is considered as a main risk factor for colorectal cancer. Prevalence of colorectal cancer has been increasing in Asian countries. Aim: The object of this study was to determine the clinical and pathology characteristics of colorectal polyps in Iranian patients and to investigate the variation between our populations with other populations. Materials and Methods: A total of 167 patients with colorectal polyps were included in our study. All underwent colonoscopy during 2009-2013 and specimens were taken through polypectomy and transferred to pathology. All data in patient files including pathology reports were collected and analyzed by SPSS 16 software. A two-tailed test was used and a P-value of < 0.05 was considered significant. Results: Mean age of participants was $57{\pm}15$. Some 84 were females (50.3%) and 83 males (49.7%). Total of 225 polyps were detected which 119 (52.9%) were in males and 106 (47.1%) were in females. Solitary polyps were observed in 124 patients (74%), 26 (15.6%) had two polyps and 17 (10.1%) with more than two polyps (three to five). Rectosigmoid was the site of most of the polyps (63.1%), followed by 19.6% in the descending colon, 7.6% in the transverse, 5.8% in the ascending, and 3.1% in the cecum, data being missing in two cases. Conclusions: Recto sigmoid was site of most of the polyps. The most prevalent type of lesion was adenomatous polyps detected in 78 (34.7%). Mixed hyperplastic adenomatous type observed in 70 (31.1%). This high prevalence of adenomatous polyps in Iranian patients implies the urgent need for screening plans to prevent further healthcare problems with colorectal cancer in the Iranian population.
-
Numerical Investigation of a New Method for Seismic Control of Structures
Mohamad Shahrokh Abdi,Masoud Nekooei,Mohammad-Ali Jafari 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.1
Vertical mass isolation (VMI) method is used for the seismic control of structures. In this method, the entire structure is considered to be a combination of two mass and stiffness subsystems with an isolator layer located in-between. A magnetorheological (MR) damper is used as the isolator layer to control the structure. The semi-active control technique is applied to control the MR damper based on the applied controlling voltage. Several single degree of freedom structures with the same masses and main periods of 0.5, 1.0, 2.0 and 3.0 seconds are studied. Finally, a comparison between the results of this method with three passive control methods was performed. Results indicated that the semi-active control method based on maximum voltage of 9V will reduce, on average, the maximum roof displacement by 25% and 51% more than the Copt and passive-off methods and is equal to the passive-on method at 9V. However, the efficiency of the semi-active method in controlling the maximum absolute acceleration of the roof and the base shear of the structure was on average 28% and 45% lower than the Copt and passive-off methods, respectively and 2% higher than the passive-on method.
-
Shahbazi, Shahrokh,Mansouri, Iman,Hu, Jong Wan,Karami, Armin WILEY-INTERSCIENCE 2018 SHOCK AND VIBRATION Vol.2018 No.-
<P>Seismic response of a structure is affected by its dynamic properties and soil flexibility does not have an impact on it when the bottom soil of foundation is supposedly frigid, and the soil flexibility is also ignored. Hence, utilizing the results obtained through fixed-base buildings can lead to having an insecure design. Being close to the source of an earthquake production causes the majority of earthquake’s energy to reach the structure as a long-period pulse. Therefore, near-field earthquakes produce many seismic needs so that they force the structure to dissipate output energy by relatively large displacements. Hence, in this paper, the seismic response of 5- and 8-story steel buildings equipped with special moment frames (SMFs) which have been designed based on type-II and III soils (according to the seismic code of Iran-Standard 2800) has been studied. The effects of soil-structure interaction and modeling of the panel zone were considered in all of the two structures. In order to model radiation damping and prevent the reflection of outward propagating dilatational and shear waves back into the model, the vertical and horizontal Lysmer-Kuhlemeyer dashpots as seen in the figures are adopted in the free-field boundary of soil. The selected near- and far-field records were used in the nonlinear time-history analysis, and structure response was compared in both states. The results obtained from the analysis showed that the values for the shear force, displacement, column axial force, and column moment force on type-III soil are greater than the corresponding values on type-II soil; however, it cannot be discussed for drift in general.</P>
-
Superstability and Stability of (r,s,t)-J*-Homomorphisms: Fixed Point and Direct Methods
Farhadabadi, Shahrokh,Park, Choonkil,Shin, Dong Yun Eudoxus Press LLC 2016 Journal of computational analysis and applications Vol.20 No.1
<P>In this paper, we introduce the following useful functional equations: f(x + y) f(x - 2y) + f (y - x) = f(x), (0.1) f(Sigma(p)(i=1) x(i)/p - 1) + Sigma(p)(i=2) f (Sigma(p)(j=1j not equal 1) x(j) - px(i)/p - 1) + f(Sigma(p)(i=2) x(i)-x(1)/p - 1) = f(x(1)) (0.2) and prove the superstability and the Hyers-Ulam stability of (r,s,t)-J*-homomorphisms, associated with those, by using the fixed point method and the direct method.</P>
KCI
스콜라연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
