Study of separation zone is so important in right-angled three-branch or four-branch open channel junctions. Some effective parameters in this case are inlet discharge ratio and flow depth which in this research the effect of inlet discharge ratio and weir height ratios (flow depth) on flow pattern and dimensions of separation zone has been simulated numerically. Investigation of numerical results showed that k-ω model well validated with experimental results and had good agreement, so that simulation error was less than 20%. Dimensions of separation zone in main and side channels were directly proportional with the inlet discharge ratio. Also as increases of height ratio of outlet weirs, flow depth increases and separation zone dimensions decreased. According to the analysis of numerical results, dimensions of separation zone in vertical direction, of the channel bed to water surface increased, so that for discharge ratio 0.6 and height ratio of outlet weirs 0.377, length of separation zone at the channel bed, 0.1 m up the bed and water surface was about 60 cm, 75 cm and 85 cm, respectively. So of the water surface towards the channel bed, length of separation zone decreased about %29.

محاسبه وزن مواد بار کوره های ذوب، با موازنه جرم عناصر آلیاژی مواد ورودی و خروجی انجام می شود. اما فرایند ذوب، پیچیدگی هایی دارد، که اغلب در محاسبات نادیده گرفته می شود، و باعث عدم اطمینان در وزن مواد بار، اصلاح چندباره ذوب، تأخیر در تخلیه، افزایش هزینه و کاهش کیفیت مذاب می شود. هدف پژوهش حاضر، توسعه مدلی است، که نه تنها وزن مواد اولیه برای ترکیب شیمیایی ذوب هدف را محاسبه و بهینه سازی کند، بلکه هدررفت ناهمگن عناصر آلیاژی، ناخالصی های غیرفلزی مواد بار، و اصلاح ذوب اولیه در کوره را نیز در نظر بگیرد. مقاله حاضر، فرمولاسیون یک مدل محاسبه بار کوره ی ذوب آلیاژ را ارایه می کند، که بر اساس موازنه جرم غیرخطی و بهینه سازی استاندارد توسعه یافته و همراه با یک الگوریتم حلقه ی تکرار برای حل عددی، ویژگی های موردنظر را برای ذوب تمام آلیاژها در برمی گیرد. برای ارزیابی مدل، یک مساله ذوب آلیاژ برنج با 7 عنصر آلیاژی و 8 نوع مواد بار در مقیاس صنعتی طرح و بررسی گردید. با حل مساله به کمک مدل توسعه یافته، کسر وزنی مواد اولیه، وزن و ترکیب شیمیایی ذوب اصلاح شده و کمترین هزینه مواد محاسبه گردید. مدل پیش بینی کرد که وزن کل مواد ورودی 9909 kg (همراه با ذوب اولیه)، هدررفت مواد معادل 262 kg، وزن نهایی مذاب اصلاح شده 9646 kg و بازدهی ذوب 97.3% باشد. تحلیل بهینه بودن جواب، تایید کرد که کمترین هزینه مواد به دست آمده است. مدل استاندارد غیرخطی، ابزاری سریع برای بهینه سازی هزینه و محاسبه بار کوره است که پتانسیل هایی برای کاهش هزینه و تسهیل اتوماسیون صنعتی فرایند ذوب ایجاد می کند.

This study proposes a micromechanical algorithm for analysis and homogenization of heterogeneous brain tissue. The presented method has led to the development of a 3D cell model for homogenization of disordered part of brain matter. The structural complexity of neuron has modeled with low level of simplification in order to achieve more accurate results. In the homogenization process the constituents of brain, neuron and extracellular cell matrix, are assumed to have an elastic behavior. The proposed model is studied in some micromechanical aspects and results indicate the model simulates the tissue behavior reasonably. Results show that because of low length to diameter ratio (aspect ratio) in the cell body, increase in number of neurons in the representative volume element has low effect on improvement of tissue mechanical properties, such as elastic modulus, and the properties are close to the prediction of lower bound or Reuss model. Investigation of stress fields caused by compression load on the representative volume element, as the part of brain tissue, announce that the maximum stress is located in the neuron and especially at the junction of neurites (axon and dendrites) and soma and also along the neurites.

In this paper the plastic deformation of single phase and two-phase polycrystal materials is studied both experimentally and by a FEM model computation, taking into account crystal plasticity. A fully coupled constitutive elastic-plastic crystal plasticity model is developed and implemented in the finite element model to define the single crystal material.A polycrystal lattice as an aggregate of single crystal grains with various orientations is both simulated and analyzed by means of unit cell method. The user-subroutine has been written for single crystals materials. Many experimental tests of polycrystal materials have been performed to trust the results of simulations. The stress versus strain dependence as obtained from this FEM-model appears to be in good accordance with experimental results.

The present study is devoted to experimental and numerical investigation of in-situ tensile tests to recognize the mechanisms of ductile fracture under different stress states. The GTN model, which is a micromechanical based damage model, has used for numerical simulations. The parameters related to this model for St12 steel were identified by response surface method (RSM) through minimizing the difference between numerical and experimental results of the tensile test on a standard specimen. The void related parameters of GTN model were determined 0. 00107, 0. 00716, 0. 01, and 0. 15 for f0, fN, fc, and ff, respectively. After calibrating the damage model for the studied material, the tensile tests were carried out on the in-situ specimens with different geometries. The fractographic analysis was performed to identify the ductile fracture under a wide range of stress states and two failure mechanisms were observed. The calibrated damage model was applied to FE simulations of in-situ tensile specimens for numerical study of the experimentally observed fracture phenomenon. The extracted numerical results showed a good agreement with experimental observations comparing load-displacement plots with a margin of error within 5%. The location of fracture initiation, crack growth orientation, and the displacement at fracture zone in numerical studies also showed close correspondence with experiments.

micro-mechanical model based on the representative volume element (RVE) is presented to study thetime-dependent and creep behavior of fibrous composite material. To this aim a finite element model ispresented for analysis of creep behavior of material in multi-axial creep are presented. The generalizedplane strain condition is employed to model the behavior of the RVE in axial and transverse normalloading. The governing equations of the problem in the RVE are discretized using the presented finiteelement method and the stiffness and force matrixes are presented. Appropriate boundary conditions areimplied to the RVE in order to consider the transverse and axial loading conditions including creepbehavior. The Euler explicit method is employed to solve the discretized equations in the time domain.The distribution of micro-stresses and the effect of creep in re-distribution of the stresses are studied.The steady state creep behavior of composite in macro-mechanical scale is investigated by analysis of the micromechanical behavior of the RVE. The macro-mechanical creep behavior of metal matrixcomposite in axial and transverse loading is predicted from the presented micromechanical model.

The volume filling ratio and type of filler significantly influence the rheological and mechanical properties of bituminous composites. This effect can stem from either chemical interactions between the filler and bitumen or simple physical phenomena. Understanding the influence of filler on asphalt mastic performance is crucial for comprehending the behavior of asphalt mixtures. This study employs both experimental and numerical modeling approaches. The rheological properties of asphalt mastic samples made with pure bitumen and limestone filler at various filler contents were determined using frequency sweep tests. The experimental results indicated that increasing the volume filling ratio in asphalt mastic leads to non-linear changes in the values of the complex shear modulus (G*) and phase angle (δ), known as the stiffening phenomenon. Considering the concept of the transitional zone between filler and bitumen, a parameter called the Effective Volume Filling Ratio (EVFR) was introduced to explain this phenomenon. To predict the viscoelastic behavior of asphalt mastic based on the mechanical properties of bitumen and filler, finite element method (FEM) simulations were utilized. The accuracy of these models was evaluated by calculating the relative difference between the experimental complex shear modulus (G*) and the complex shear modulus predicted by the model. The results of this evaluation indicated that incorporating the Effective Volume Filling Ratio (EVFR) into the numerical model can significantly enhance the accuracy of the predictions for the viscoelastic behavior of asphalt mastic samples.

با توجه به محدودیت منابع آب زیرزمینی در ایران، محاسبه دقیق، استفاده صحیح، تنظیم و نگهداری این منابع از اهمیت بالایی برخوردار است. یکی از روش های مؤثر برای مدیریت و بهره برداری بهینه از این منابع در حال و آینده، استفاده از مدل سازی است. در این پژوهش مدل سازی تغییرات تراز آب زیرزمینی به صورت ماهانه در دورۀ 2022-2013 با مدل های MLP، WNN و MLPSSO-Wavelet انجام شد که از داده های نه سال اول برای آموزش و سال آخر جهت اعتبارسنجی استفاده شد و بهترین مدل با استفاده از معیارهای ضریب تبیین (R2)، ریشه میانگین مربعات خطا (RMSE) و میانگین خطای مطلق (MAE) تعیین گردید. بارش و دمای ایستگاه سینوپتیک شبستر در دوره آینده (2040-2021) با استفاده از مدل CanESM2 تحت سناریوهای RCP2.6 و RCP8.5 که ارتباط منطقی و مناسبی با ویژگی های اقلیمی مشاهداتی دارند پیش بینی و با استفاده از مدل LARS -WG ریزمقیاس سازی شدند. در دورۀ آتی، تحت هر دو سناریو و در ماه های فوریه ، جولای و اکتبر میانگین بارش کاهش و در نه ماه دیگر افزایش خواهد یافت. برای دما نیز به جز سناریو RCP8.5 و ماه ژوئن، در 11 ماه دیگر و تحت هر دو سناریو، افزایش دما پیش بینی می شود و بیش ترین افزایش دما (43/37 درصد)، در ماه ژانویه و تحت سناریو RCP2.6 خواهد بود. تراز آب زیرزمینی آبخوان دشت شبستر با افت 42/4 متری، از 64/1303 متر در سال 2003 به 22/1299 متر در سال 2022 رسیده است. مطابق نتایج، مدل MLPOSSO-Wavelet با 83/0R2=، 74/0RMSE= و 71/0MAE= در مرحلۀ اعتبارسنجی، دقت بیشتری نسبت به مدل های دیگر دارد. تراز آب زیرزمینی دشت شبستر تحت سناریو RCP2.6 در شش ماه ابتدایی کاهش و در شش ماه دوم نسبت به شش ماه اول افزایش خواهد یافت. تحت سناریو RCP8.5 فقط در ماه های ژانویه، فوریه و دسامبر کاهش تراز آب زیرزمینی پیش بینی می شود و بیش ترین کاهش در ماه ژانویه اتفاق خواهد افتاد.

Objective: Advances in microelectromechanical (MEMS) technologies over the past few decades have contributed to the rapid development of a wide range of microfluidic devices with different functionalities. Fluids are driven through microfluidic systems, therefore, in the current research, it is intended to parametrically investigate the effects of the main parameters, namely length, width and angle of attack of valves, piezoelectric length and applied voltage. Method: The approach of the present research is applied and analytical-experimental with numerical simulations where the tensile force is calculated using COMSOL Multiphysics software and the equations are calculated using the fully coupled algorithm in COMSOL Multiphysics. Findings: The results of the present research show that the main parameters significantly affect the performance of the designed micro pump. So that the applied voltage is 400 volts, the angle of attack is 45 degrees and the width of the valves is 6 micrometers, respectively for the piezoelectric length of 4, 2 and 5 mm, the flow rate is 6. 0.6, 9.6 and 16.6 microliters per minute are obtained. For valve widths of 6 and 8 micrometers, optimal attack angles of 60 and 65 degrees, the corresponding flow rates are 11.11 and 5.9 microliters per minute, respectively. Conclusion: Based on the results of the present research and the investigation of the behavior of the micropump and its output flow rate changes in different working conditions, as the length of the valves increases, the flow rate provided increases. Finally, there is a favorable condition for the width and angle of attack of the valves. This optimal width does not depend on the flow speed.