In this paper, recommended spiral passive micromixer was designed and simulated. spiral design has the potential to create and strengthen the centrifugal force and the secondary flow. A series of simulations were carried out to evaluate the effects of channel width, channel depth, the gap between loops, and flowrate on the micromixer performance. These features impact the contact area of the two fluids and ultimately lead to an increment in the quality of the mixture. In this study, for the flow rate of 25 μl/min and molecular diffusion coefficient of 1×10-10 m2/s, mixing efficiency of more than 90% is achieved after 30 (approximately one-third of the total channel length). Finally, the optimized design fabricated using proposed 3D printing method.

Introduction: Although there are exact solution to atmospheric radiative transmission equations, they are not suitable for use in atmospheric general circulation models (GCM). The parameterization of atmospheric radiation for use in an atmospheric GCM is to provide a simple, accurate and fast method of calculating the total radiative flux.Aim: A review of some techniques used to compute radiation flux for use in NUMERICAL GCMs and intercomparison output of some GCMs include various methods of radiation parametrization.Materials and Methods: we review the various methods used to compute both the radiative fluxes of longwave (LW) and shortwave (SW) for use in NUMERICAL climate models.This paper discusses various methods of integration of absorption over frequency, parameterization of scattering and absorption due to atmospheric gases, separately, at both the SW and LW, surface absorption and aerosols. Then, output data from some atmospheric GCMs with different radiation parametrizations are compared.Results: Line by line is one of exact radiation transmission methods for calculating of gases absorption in inhomogeneous atmosphere which considers all absorption lines. Adding- Doubling, discrete ordinate and Monte Carlo are some of exact techniques in calculation of radiation intensity of SW that have been used as a reference of parametrization. There are four integrations of all zenith angles, z-direction fluxes, du spectral interval and optical absorption path in LW equations. K-distribution, band methods and emissivity methods are among approximation methods in estimation of spectral interval. For each gas, depending on absorption band, different absorption coefficient and therefor different transfer function are available. Non-scattering atmosphere approximation, single scattering approximation, two stream solutions and Eddington approximation estimate SW radiative flux. Radiative transmission parametrization methods are investigated in some GCMs. Finally, data outputs containing absorbed Sw radiative flux in surface and atmosphere and LW radiative flux in surface are compared together and with observation data.Conclusion: radiation parameterization schemes run in GCMs may generally be different, but there are the same solutions for some parts of radiation flux calculation employed at some schemes. Global mean radiation budget calculated by GCMs especially at the earth’s surface are different. Compared to observations, the GCMs include a tendency towards more excessive surface insolation and a smaller longwave downward radiation at the surface.

The phenomenon of unsupported sleepers is considered one of the most critical factors affecting the dynamic performance of ballasted railway tracks. Disrupting the contact between the sleeper and the ballast leads to increased deflection, stress concentration, and reduced track stability. This study aims to NUMERICALly analyze and simulate the dynamic effects of unsupported sleepers, focusing on their numbers and layout patterns in the ballasted railway tracks. For this purpose, a three-layer mechanical model consisting of rail, sleeper, and ballast was developed in MATLAB, and its results were compared with an equivalent finite element model created in ABAQUS. The MATLAB model employs mass, stiffness, and damping matrices along with a time-dependent moving load to evaluate the system's response under various unsupported sleeper conditions. In the ABAQUS model, sleepers and ballast were modeled as concentrated masses, with their interactions represented via equivalent spring-damper systems; loading was applied incrementally along the train path. The results indicate that increasing the number of unsupported sleepers—particularly in sequential arrangements—significantly amplifies rail deflection and mid-span stress, with the most critical response observed in the case of three-consecutive-unsupported-sleepers. These findings indicate the necessity of continuous monitoring and preventive maintenance of unsupported zones to ensure track safety and extend structural service life.

In this research, in order to investigate the effect of the piezoelectric patch which is used as a sensor or actuator in rotating flexible structures such as a helicopter blade, the free vibrations of the rotating rectangular sheet with and without the piezoelectric patch have been presented. First-order shear deformation theory is considered for plate displacement and piezoelectric field. Considering the effect of Coriolis acceleration, centrifugal acceleration and centrifugal in-plane forces, the equations of motion are derived from Hamilton's principle and the electromechanical couple equation is obtained from Maxwell's equation. For piezoelectric, two electrical conditions, open circuit and closed circuit, which are used in sensors and actuators, respectively, have been considered. The equations are discretized with the help of the NUMERICAL method of generalized differential squares and the matrices of inertia mass, eccentricity, Coriolis and stiffness matrix are obtained. Natural frequency values for beam and rotating plate have been compared in Abaqus software. Also, the values obtained from the NUMERICAL solution in MATLAB have been verified with articles and ABAQUS, which have high accuracy. The effect of parameters such as hub radius, rotation speed, sheet thickness, aspect ratio, piezoelectric patch thickness and applied voltage on the natural frequency of the system has also been investigated.

Plastic hinge properties play a crucial role in predicting the nonlinear response of structural elements. The plastic hinge region of reinforced concrete normal beams has been previously studied experimentally and analytically. The main objective of this research is to evaluate the behavior of the plastic hinge region of reinforced concrete deep beams and its comparison with normal beams through finite element simulation. To do so, ten beams contain six deep beams, and four normal beams, under concentrated and uniformly distributed loading, are investigated. Lengths in the plastic hinge region involving curvature localization, rebar yielding, and concrete crushing zones are studied. The results indicate that the curvature localization zone is not suitable for the prediction of plastic hinge length in reinforced concrete deep beams. Based on the results it can be stated that in simply supported normal beams the concrete crushing zone is focused on the middle span, but in simply supported deep beams by creating a compression strut between loading place and support, the concrete crushing zone spreads along the compression trajectory. The rebar yielding zone of simply supported beams increases as the loading type is changed from the concentrated load at the middle to the uniformly distributed load.

This paper examines four models of media effects, i.e., direct, conditional, accumulative and cognitive effects as well as the important variables in each model. These models demonstrate four different processes of media effects obtained from different studies. The models differ in that each one focuses on a specific aspect of media content or audiences as the recipients of media effects. These four models are designed to classify the explanations. Since each model focuses only on some parts of the reasons behind media effects, none of them alone can explain the effects of media in whole. However, importance and value of these models is due to the fact that they can help examine the media effects processes directly. Finally, the article proposes some suggestions for managers, planners and programmers of different media, especially radio and television.

In recent years, the tendency to short-term format has been considered by poets. Priskeh is one of the types of contemporary Persian short poems that was officially registered by the Ministry of Culture and Islamic Guidance in 2012. Based on this research, it was concluded that Priskeh is an independent short format that has its own characteristics and has significant structural and material differences. And the goal is to recognize more and more Priske short template as a short short template and introduce its special features. Some poets take their poems haiku while none of them followed their principles. but declared to the Japanese poem that; Accordingly, sometimes, with the rules of your acquaintance, Priskeh has also made Persian haiku or imitation of them.