The present study involves a novel computational TECHNIQUE, regarding simultaneous use of the pseudo particle method, Poisson integral method and a special-purpose computer originally designed for molecular dynamics simulations (MDGRAPE-3). In the present calculations, the dynamics of two colliding VORTEX rings have been studied using the VORTEX method. The present acceleration TECHNIQUE allows the calculation of 107 VORTEX elements. The reconnection of the VORTEX rings was clearly observed, and the discretization error was nearly negligible.

Investigation of particle movement pattern in VORTEX Settling Basin based on particle tracking TECHNIQUE1. Elnaz Mehrabani/ M.Sc student in Water Structures, Ferdowsi University of Mashhad, Iran.2. Ali Naghi Ziaei/ Professor, Department of Water Science and Engineering, Ferdowsi University of Mashhad, Iran.3. Neda Sheikh Rezazadeh Nikou/ Postdoctoral researcher, Ferdowsi University of Mashhad, Iran.4. Mahmoodreza Golzarian/ Professor, Department of Biosystems Engineering, Ferdowsi University of Mashhad, Iran.Introduction The quality of water required for agriculture, industry, drinking, etc., has made it necessary for the solids particle in the water flow to enter its permissible level in irrigation and drainage or urban water networks. The VORTEX Settling Basin (VSB) makes use of the VORTEX flow inside the chamber for the separation of sediment particles from the flow.Elaborate studies have been made on investigation flow pattern at VSB that includes: (Paul, 1988 and 1991; Athar et al., 2003; Gheisi, et al, 2006; Ziaei et al., 2007; Chapokpour et al., 2011; Mulligan et al, 2016; Rehman et al., 2017; Huang et al., 2017; S. R. Nikou et al., 2021).Elaborate studies in hydraulic sciences apply particle tracking and image processing method for investigation ( Sun et al., 2015; Shin et al., 2016; Mulligan et al., 2016 and 2018; Rosberry et al., 2019; Witz et al., 2018; Duinmeijer et al., 2019).The investigation of VORTEX flow is very sensitive to measuring instruments, for example, ADV, which is the most common instrument for measuring the velocity, increases disturbance of flow. Therefore, it is recommended to use the non-interference particle tracking method to measure velocity components.Methodology The experiments were performed in the hydraulic laboratory of the water science and engineering department at the Ferdowsi University of Mashhad, Iran on an acrylic laboratory setup. Spherical particles with a relative density of 1.41, at distances of 37 cm and 1.5 m from the chamber (sediment injection site in the study of Athar et al., (2003)) and in these two longitudinal distances, left at 9 points and each experiment is repeated 5 times (Figure 2).In this research, two iPhone 7 Plus cameras have been used for taking photos. The camera of this phone has one of the most advanced cameras in terms of expertise and technology. In this study, due to the high volume of data at different points, image processing is presented in the highest probability of trapping (point 4), the position of this point is as follows: 5 cm from the floor, 2 cm from its right wall (sloping to the chamber), 18 cm from the sloping wall to the outlet channel and 6.5 cm to the water level. The input flow to the channel is 8 and 13.7 l/s.Results and Discussion The highest probability of trapping for a particle at two longitudinal distances is at point 4 with a probability of 60%. The process of particle displacement and the time series of three velocity diagrams in the VORTEX settling basin of the present study are sinusoidal. In sections 150°-210° and 330°-30°, the particle is inclined toward the wall and in other sections, it is inclined toward the orifice, affected by the location of input and output channels (S. R. Nikou et al., 2021). There is a meaningful correlation between the two components vx and vy, and in almost all places where the x velocity component is extreme, in the same position y component is zero, and vice versa. This result is quite justifiable given the motion of VORTEX flow. The extreme values of the velocity component in the x direction become closer as they approach the orifice, indicating an increase in velocity near the orifice and the chamber floor and a smaller curved path around the VORTEX core. Notably, the absolute value of the maximum velocity in the x direction is 1.61 m/s and in the z direction is 0.13 m/s, which indicates that the particle tends to enter the orifice more in a rotating passage than falling position, having said that, centrifugal force is dominated over the action of dewatering. The mean relative error of water surface profiles by image processing method compared to laboratory data is estimated to be 0.002 and 1.36%, respectively, which confirms well with the experimental measurements.Conclusion The results showed that the distribution of the velocity components of the particle in all three dimensions has a sinusoidal trend. The higher value of the maximum velocity in the x-direction than the z-direction indicates the dominance of the centrifugal force over the dewatering operation in the VORTEX flow.According to the obtained results, particle tracking and image processing can be used as an accurate method with a higher operational speed to investigate the flow patterns and determine the water surface profile in VORTEX settling basins.KeywordsPTV, Particle tracking, Orifice at the center, Point gauge, Velocity distributions.

The objective of the present study was to evaluate the mechanical properties of Al/ZrO2 composites produced via VORTEX TECHNIQUE. Al-356 alloy and ZrO2 particles with average diameter of 0.79 micron were used as the matrix and the reinforcement, respectively. The effect of ZrO2 content and casting temperature on tensile strength and fracture surfaces of the composites were studied. The results indicate that addition of ZrO2 particles into the matrix significantly increases mechanical properties of aluminum alloy. In this regard, the best tensile strength result was obtained in the specimen containing 15 vol% ZrO2 produced at 750oC which showed an increase of about 60%. The Al-356/ZrO2 composite specimens fracture in a brittle manner with little or no necking has been observed.

The objective of the present study was to evaluate the mechanical properties of Al/ZrO2 composites produced via VORTEX method. Al-356 alloy and ZrO2 particles with average diameter of 0.79 micron were used as the matrix and the reinforcement, respectively.The results indicate that addition of ZrO2 particles into the matrix significantly increases mechanical properties of aluminum alloy. In this regard, the best tensile strength result was obtained in the specimen containing 15 vol% ZrO2 produced at 750oC which showed an increase of about 60%. The Al-356/ZrO2 composite specimens fracture in a brittle manner with little or no necking observed.

Aims The use of intrauterine devices (IUDs) has been one of the most effective, the safest and cost-effective methods for preventing pregnancy, for a long time. However, some complications have been reported for IUDs. The complications may be reduced by using a specific TECHNIQUE for placement of IUD. The objective of this study was to introduce the rotating withdrawal TECHNIQUE for the first time, which was investigated to reduce the complications of IUD insertion. Materials & Methods This historical cohort study was conducted on 1199 females who referred to Sarem Medical Center for IUD insertion from 1984 to 1995. After primary examinations, IUD was inserted by rotating withdrawal TECHNIQUE. The subjects were followed up for 2 years. Findings Displacement was observed just in 20 cases (1. 67%). All of them were seen in the first month after placement. For these cases, IUD insertion was done again. After the second replacement, displacement was observed in 4 cases (0. 035%) after one month. Therefore, it was recommended to them to use another preventive method. There was no pregnancy or displacement in the other cases during 2 years. Conclusion The rotating withdrawal TECHNIQUE can minimize the pregnancy rate when IUD is used. In addition to the type and quality of IUD, insertion method of IUD can increase its effectiveness.

In this paper, a new method for extending and relaxing the noise-coupling (NC) TECHNIQUE is proposed to enhance the noise-shaping order without adding the number of integrators. The noise-shaping order of the introduced ∑∆ modulator whit applying a second-order noise-coupling TECHNIQUE is enhanced and its performance with optimizing the noise transfer function (NTF) zeros is improved. Also, by removing the analog adder at feedforward path and transferring it to a new feedback branch before the last integrator and adding second-order NC path can be decreased the input voltage swing to the quantizer. Thus, by improving the modulator resolution, power consumption can be reduced. Mathematical analyses and behavioural simulation results confirm the effectiveness of the new NC method. To examine its performance, a 2nd-order single loop ΣΔ modulator was designed. The new noise-coupling method is used to achieve the three-order noise shaping to increase the resolution with low complexity and low-power. The results show an outstanding improvement in signal-to-noise and distortion ratio (SNDR) compared to the conventional structure.

Consumption of cutting fluids imposes high costs on industry. These cutting fluids contaminate the environment and are harmful to human health. Minimum quantity lubrication TECHNIQUE (MQL) is a new approach to reduction of cutting fluids consumption, improving efficiency of cutting fluid at machining zone and using harmless fluids. However, this TECHNIQUE faces cooling limitation in grinding. The purpose of this study is an accurate study of heat transfer mechanism in minimum quantity lubrication TECHNIQUE by its temperature numerical simulation and improving the cooling ability of its air jet by using a simple and inexpensive VORTEX tube. For this purpose, a system was designed and manufactured to measure the convection heat transfer coefficient of different conditions of MQL environments. The result of convection heat transfer tests shows 95% share of compressed air in heat transfer and also air pressure is a more important factor than temperature in cooling process. The result of temperature numerical simulation shows that by increasing pressure, the increasing rate of convection heat transfer coefficient decreases; also, the cooling ability temperature of the VORTEX tube at low thermal power is tangible. In grinding of soft steel, the minimum quantity lubrication TECHNIQUE with cold air (CAMQL) in comparison with other methods leads to significant reduction of tangential grinding force and friction coefficient, but in general, except in the case of optimum condition which has the highest heat transfer coefficient, surface finish is worse, which is related to low heat transfer coefficient of gases at low pressures.

In this research, aerodynamic performance of a double s-shaped serpentine inlet duct is numerically investigated by using of blowing Jet VORTEX generators flow control TECHNIQUE. At first, turbulence equations are validated by comparing the numerical results with experimental test data of a standard inlet, and aerodynamic loss parameters of a sample serpentine inlet are estimated in flight condition of Mach=0. 7 at Altitude=9000m. Then the effect of active flow control technic on the loss parameters are studied by installing two sets of 20 blowing VORTEX generators on the upper and lower walls of the duct in 5 separated and integrated arrangement schemes by simulating 0. 01 and 0. 02 blowing mass flow ratios. By comparing between 5 schemes with clean duct in the fields of blowing mass flow ratio, 2% blowing ratio has better improvement results in all schemes. In the field of arrangement position, C3 and C5 schemes respectively by 3. 1% and 3. 12% increase in total pressure recovery, 67. 16% and 64. 66% decrease in DC(60) distortion coefficient and 71. 8% and 64. 5% decrease in DPCP coefficient at 2% blowing mass flow ratio, are selected as the best flow control scheme.

Annular VORTEX tube is a VORTEX tube which allows the hot flow pass again over the hot tube. It is introduced for first time in this work. Hot Flow is not allowed to exit after passing conic valve in annular VORTEX tube, but it is redirected over hot tube. This back flow absorbs heat from outer wall of hot tube. To study temperature separation which occurs in an annular VORTEX tube; the performance of this type of VORTEX tube has been experimentally tested and compared with the performance of a typical VORTEX tube. Inlet test pressure is 4 bars and natural gas is being used as working fluid. For both type of VORTEX tubes, ratio of length to diameter of tube is 10. Cold oriice diameter of VORTEX generator is set to 6.4 mm. It was observed that redirecting hot flow over the hot tube in annular VORTEX tube improves cooling efficiency up to 24% respect to a typical VORTEX tube at the maximum temperature difference. The results show that cold mass fraction in which the coldest temperature occurs is lower for annular VORTEX tube comparing with a typical VORTEX tube.

For a long time, many efforts have been taken on improving gas turbine performance to increase the propulsive force and keep the chamber walls cool. In this regard, implementation of cyclonic and VORTEX engines have been proposed. According to increasing in the engine efficiency and keeping the chamber walls cool, the bidirectional VORTEX flow which is exited in the VORTEX engine, makes researchers more interested in it. In the VORTEX engine, due to its specific geometry, two VORTEX layers are established. The combustion occurs in the inner VORTEX layer, while the outer layer protects the walls from excessive heat transfer. The VORTEX engine with gas fuel and oxidizer has been manufactured in laboratory scale at Virginia Institute of Technology and it is under investigation. Practical usage of the VORTEX engine, with both liquid and solid fuels, has its own significance. Investigation and analysis of the flow field in such a chamber have been conducted in different research centers during last five years. The significant results of these studies are the analytical and numerical solution of the flow field by applying many simplifying assumptions. Selecting proper materials, determining the engine dimensions, designing injector plate, and some other parameters in engine manufacturing process require the flow field to be modeled in the combustion chamber which needs the governing equations to be solved. For investigating of the flow field in the VORTEX engine, the mass conservation, momentum conservation, and energy equations have to be solved. If the flow is turbulent, the equations become more complicated and many assumptions are needed to simplify the problem. Note that, by assuming the flow to be incompressible, the energy equation becomes segregated from the other equations. At the first stage, the goal of this project is to investigate the previous analytical solution and modify it to become compatible with other numerical and experimental results, provide numerical solution of the governing equations with the least possible assumptions, and compare the obtained numerical and analytical results with each other. Since the governing equations are non-linear and the flow is turbulent, it is impossible to solve the problem analytically in details. The flow will be simulated with respect to the result of numerical solution and applying the conventional methods and the results will be presented. It is to be noted that, if the fuel is liquid, modeling the spray combustion in a two-phase (gas-liquid) flow field is required, which will be described in this project as well. According to the flow field analysis, the propulsive and aero-dynamical results of the engine will be available, which are required to determine the designation parameters and manufacturing of the VORTEX engine test rig. Afterwards, by establishing the fundamental requirements for installing the appropriate test rig for the VORTEX engine, manufacturing of this test rig with its accessories will be described in details. The obtained results of this project, including the flow field investigation, test rig designation and implementation, are the first steps to achieve mass production of the VORTEX engine with both liquid and gas fuels which, according to its innovation and efficiency, has its own significance.