69 research outputs found
Calculation of Dynamic Amplification Factor for Railway Concrete and Masonry Arch Bridges Subjected to High-speed Trains
The dynamic amplification factor (DAF) is one of the most important parameters to express the dynamic behavior of bridges under moving loads. This parameter is used in bridge design codes instead of exhaustive dynamic analyses. Therefore, the DAF and the possible derived relationships can be good alternatives to dynamic analyses because of time and computational cost savings. Masonry arch bridges are complex infrastructures due to their geometry and structural behavior, and it is troublesome to prepare an accurate numerical model. To conduct dynamic analyses, due to their multiplicity, calculating the DAF of the bridges imposed by high-speed trains can lead to a rapid assessment of these old railway arch bridges. For this purpose, in the present study, the finite element models of two concrete and masonry arch bridges with small fill material heights, which are completely different in terms of geometric and mechanical characteristics, were prepared. In the next step, by performing 378 dynamic analyses based on the 27 different train models, the DAF has been computed. The results show that the calculated DAFs are in the rational range, and bogies interval, axles interval, and span length are recognized as the most important parameters in the DAF changes
The Effect of Central Bank Transparency on Macroeconomic Stability in Emerging Economies
Macroeconomic instability is an important obstacle to the real growth of the economy and its sustainability. In this article, two methods have been used to investigate the impact of transparency on macroeconomic stability in emerging economies using simultaneous equations with panel data for the period 1998-2014. In the first method, two equations for central bank transparency and stability have been considered and the mutual effect of these two variables has been investigated. In the second method, three equations for the variables of stability, including inflation, production gap and real exchange rate gap, and one equation to measure the effect of these variables on transparency are used simultaneously. The results of the study show that the transparency of the central bank is one of the factors affecting the stability of the macroeconomics. Also, the square of the central bank's transparency variable has a negative and significant relationship with macroeconomic stability. Meanwhile, the transparency of the central bank has an inverse relationship with inflation and the real exchange rate gap, and there is a two-way relationship between the transparency of the central bank and inflation. Finally, the effect of central bank transparency on production gap and vice versa is not significant
Using fuzzy logic approach to predict work-related musculoskeletal disorders among automotive assembly workers
Background: Musculoskeletal disorders (MSDs) are considered an important health concern, particularly in automotive assembly industries. Evaluation of the effects of all MSDs risk factors is difficult due to its multifactorial nature. In addition, the risk factors cannot be detected accurately when they are only based on individual opinions. Thus, in this study, fuzzy logic tool was used to evaluate the combined effects of all risk factors on MSDs. Methods: This cross sectional study was conducted on 100 male workers in an automotive industry. Job satisfaction, job stress, job fatigue, and body posture were evaluated by a self-reported questionnaire. Body posture was evaluated using Rapid Entire Body Assessment (REBA). Primary data analysis on extracting the input variables of MATLAB was performed by SPSS 22, with a significant level of 0.05. T test, one-way Anova, and Pearson correlation analysis were used to extract the input variables for the fuzzy logic model. The results obtained from the Nordic questionnaire was selected as the output of the fuzzy model. Fuzzy logic assessment was performed using MATLAB software version 7.0. Results: There were significant differences between WMSDs factors, including job fatigue, strain, working posture, and the REBA final score, and pain in all limbs of the body (p<0.05). A significant difference was also found between working posture with wrist score (p<0.05). The findings on defuzzification showed a strong correlation between real and modelling results. Conclusion: The results showed that many factors such as posture, fatigue, and strain affect MSDs. Based on the obtained results, all categories of risk factors, including personal, psychosocial, and occupational, should be considered to predict MSDs, which can be achieved by a modeling approach.
Keywords: Automotive industry; Fuzzy logic; Work-related musculoskeletal disorders
Experimental investigation on the energy absorption and contact force of unstiffened and grid-stiffened composite cylindrical shells under lateral compression
Indoor environment assessment of special wards of educational hospitals for the detection of fungal contamination sources: A multi-center study (2019-2021)
Background and Purpose: The hospital environment was reported as a real habitat for different microorganisms, especially mold fungi. On the other hand, these opportunistic fungi were considered hospital-acquired mold infections in patients with weak immune status. Therefore, this multi-center study aimed to evaluate 23 hospitals in 18 provinces of Iran for fungal contamination sources.Materials and Methods: In total, 43 opened Petri plates and 213 surface samples were collected throughout different wards of 23 hospitals. All collected samples were inoculated into Sabouraud Dextrose Agar containing Chloramphenicol (SC), and the plates were then incubated at 27-30ºC for 7-14 days.Results: A total of 210 fungal colonies from equipment (162, 77.1%) and air (48,22.9%) were identified. The most predominant isolated genus was Aspergillus (47.5%),followed by Rhizopus (14.2%), Mucor (11.7%), and Cladosporium (9.2%). Aspergillus(39.5%), Cladosporium (16.6%), as well as Penicillium and Sterile hyphae (10.4% each), were the most isolates from the air samples. Moreover, intensive care units (38.5%) and operating rooms (21.9%) had the highest number of isolated fungal colonies. Out of 256 collected samples from equipment and air, 163 (63.7%) were positive for fungal growth.The rate of fungal contamination in instrument and air samples was 128/213 (60.1%) and 35/43 (81.2%), respectively. Among the isolated species of Aspergillus, A. flavus complex (38/96, 39.6%), A. niger complex (31/96, 32.3%), and A. fumigatus complex (15/96, 15.6%) were the commonest species.Conclusion: According to our findings, in addition to air, equipment and instrument should be considered among the significant sources of fungal contamination in the indoor environment of hospitals. Airborne fungi, Hospital, Indoor air, Equipment, Sources of fungal contamination in the indoor environment of hospitals
Hick’s Religious Pluralism and Plantinga’s Exclusivism in a Comparative Encounter
The issue of religious diversity is one of the significant issues in philosophy of religion. The existence of different religions in the world is an inevitable fact. Nowadays, due to the unprecedented development of information technology and public awareness of different beliefs across the nations have made the acknowledgement of religious diversity more widespread than the past. Being this the case, the questions as to religious diversity have been taken to the fore and contemporary man finds himself exposed to the question that how should a believer approach the other beliefs? Could all religions despite the differences they have in their dogmas, beliefs and doctrines be legitimate? Will the followers of all beliefs touch salvation?
Accordingly, among the key issues of philosophy of religion are the issue of legitimacy of different religions and the issue of salvation of followers of different creeds. This essay is an epistemological assessment of Hick and Plantinga on the legitimacy of religions in a comparative context. The following questions represent the guidelines of the present essay:
How much is pluralism rationally and epistemologically feasible in its claim as to the legitimacy of all beliefs and the equal access of followers of all creeds to salvation?
Does Plantinga's exclusivist taking as to religious truth and salvation and narrowing them down to Christianity and Christians have rational and epistemological justification?
Hick has propounded his pluralism as a cure to difficulties caused by Christian religious exclusivism and inclusivism. Having insisted on the salvation promoting evolution from egotism to theism as the basic substance of religion, Hick traces the differences of religions back to the inattention to the symbolic language of religion. On the other hand, Plantinga takes the existing differences between religions as an evidence indicating the contradictoriness of pluralism and legitimacy of religious exclusivism. In explaining and defending his exclusivistic position, he rejects both moral and epistemological criticisms. Finally through his "proper function theory" and borrowing from the "Aquinas- Calvin Model" Plantinga tried to justify the validity of their religious exclusivism. By comparing these two ideas and their principles and arguments, it seems that both takings on major issues, particularly in terms of epistemological justification, are confronted with some problems. Although, one can use the theistic universal compassion to support the aspect of salvation which Hick claimed, but his view concerning the aspect of truth is not strong enough. That is to say that Hick’s major evidences for religious pluralism are confronted with some outstanding problems. By examining Plantinga’s view, it will be shown that his efforts in rejecting the moral criticisms that the pluralists contended were successful. However, his attempts to justify the idea of exclusivism were not epistemologically good enough.The final conclusion in this research is that Plantinga’s exclusivism according to which truth and salvation are embedded only in Christianity does not have good epistemological justification. Close examination of Hick’s pluralism shows that his view is confronted with some epistemic problems too. However, it seems that Hick's theory, for the emphasis on the aspect of the tolerance between faiths, is more attractive than Plantinga’s religious exclusivism
Knowledge Management and Learning Organization: Analyzing the Role of Knowledge and Experience Documentation
سازمانها علیرغم سرمایهگذاریهای سرسامآور سختافزاری و نرمافزاری که برای استقرار مدیریت دانش انجام دادهاند به نتیجه مورد انتظارشان دست نیافتهاند. تحقیق حاضر تلاشی است برای پاسخگویی به این سؤال بنیادین که سازمان با تکیه بر چه رویکردی میتواند به مزیت رقابتی مبتنی بر منابع کلیدی خود دست یابد؟ و به عبارتی مسیر بلوغ سازمان در بهرهبرداری از دانش خود چیست و سازمان روی چه فرآیندهایی سرمایهگذاری کند تا پیادهسازی مدیریت دانش در جهت اهداف و نیازهایش باشد؟ روش تحقیق بکارگرفته از نظر نوع دادهها کیفی، از نظر ماهیت اکتشافی و از نوع نظریه برخاسته از دادهها است که با نمونه گیری هدفمند و انجام مصاحبهها عمیق و نیمه ساختار یافته (فردی و گروهی) صورت گرفته است، تجزیه و تحلیل دادهها با استفاده از روش تحلیل مقایسه ای انجام شده است. این الگوی فرآیندی نشان میدهد که توسعه مدیریت دانش از طریق یک فرآیند یادگیری چهار حلقهای محقق میشود بهگونهای که منابع سازمانی در طی این فرآیند، ارتقاء یافته و به قابلیتها و شایستگیهای محوری سازمان تبدیل میشوند. بنابراین اگر سازمان نتواند محقق شدن این فرآیند را فراهم نماید، سرمایهگذاری انجامشده به هدر خواهد رفت. فرآیند ارائهشده، مراحل توسعه و پیادهسازی مدیریت دانش را توصیف میکند و نقش هریک از عوامل اساسی همچون فرآیندها و حلقههای یادگیری، منابع سازمانی و استفاده خلاقانه از فناوری اطلاعات را در پیادهسازی مدیریت دانش تبیین مینماید
- …