هدف: هدف پژوهش حاضر، ساخت و اعتبار­سنجی سیاهه آسیب‌شناسی روانشناختی نوجوانان در فضای مجازی بود. روش: روش آمیخته اکتشافی (کیفی-کمی) بدین منظور با استفاده از تحلیل مضمون مقالات مصاحبه‌های انجام‌شده متخصصان فعال مجازی، آسیب­ ها شناسایی شدند بر اساس آن ­ای ساخته شد. جامعه آماری بخش کیفی شامل مقالات، اساتید دانشگاه­ های اراک، اصفهان، امام خمینی قزوین شهر اراک بودند که نمونه هدفمند آنها انتخاب کمی بو...

Optimum design of steel frames is a complicated process because the designer has to consider a large number of nonlinear constraints which are imposed by steel design codes while also dealing with discrete design variables. Obtaining the optimum solution to discrete programming problems was never easy until the emergence of metaheuristic techniques. The firefly algorithm, one of the recent meta...

Computational cost of metaheuristic based optimum design algorithms grows excessively with structure size. This results in computational inefficiency of modern metaheuristic algorithms in tackling optimum design problems of large scale structural systems. This paper attempts to provide a computationally efficient optimization tool for optimum design of large scale steel frame structures to AISC...

This paper presents an ant colony system model for cost optimization of a composite floor system based on the load and resistance factor design (LRFD) specification of the AISC. The model formulation includes the cost of concrete, steel beam, and shear studs. The objective function is considered as the cost of the structure, which is minimized subjected to serviceability and strength requiremen...

The use of Fiber Reinforced Polymer (FRP) reinforcement is a practical alternative to conventional steel rebars in concrete structures subjected to aggressive environments. The solution is attractive for bridge deck and rail applications, as it eliminates corrosion of the steel reinforcement, which is the major instrument of degradation. Due to the peculiar physical and mechanical characteristi...

Load models are developed for highway bridges. The models are based on the available statistical data on dead load, truck loads and dynamic loads. The paper deals mostly with the static live load. The model is derived from truck surveys, weigh-in-motion measurements and other observations. Simple span moments, shears and negative moments are calculated for various spans. Extreme 75 year loads a...

هدف: پژوهش حاضر با هدف بررسی مقایسه اثربخشی گروه درمانی شناختی – رفتاری و ذهن ­آگاهی مبتنی بر شناخت کاهش رفتارهای پرخطر در معتادان ترک افیونی صورت گرفت. روش: روش این شبه آزمایشی طرح پیش آزمون پس همراه کنترل است. جامعه­ی آماری شامل کلیه افراد وابسته به مواد مراجعه کننده مرکز اعتیاد شبکه بهداشت درمان شهرستان سرپل ذهاب نیمه اول سال 1396 بود، نمونه­ گیری دسترس تعداد 36 نفر تشخیص وابستگی اساس معیاره...

Load and resistance factor design (LRFD) is widely used in building codes for reliability design. In the calculation of load factors, third-moment method (3M) has been proposed to overcome shortcomings (e.g., inevitable iterative computation, requirement probability density functions (PDFs) random variables) other methods. With existing 3M method, simplified one PDFs variables are not required....

In this study, 11 PSRPC column specimens were designed and fabricated in order to investigate the stressing performance of incompletely prefabricated steel reactive powder concrete (PSRPC) columns subjected static loading tests. The effects strength grade content (RPC) on axial compression eccentricity investigated. test results show that external RPC, internal section cast-in-place RPC work we...