Search results for: micro drops

Authors: Khelfaoui Rachid, Chekifi Tawfiq, Dennai Brahim, Maazouzi A. Hak

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A numerical and experimental studies of passive micro drops production have been presented. This paper focuses on the modeling of micro-oscillators systems which are composed by passive amplifier without moving part. The micro-system modeling is based on geometrical oscillators form. An asymmetric micro-oscillator design that is based on a bistable fluidic amplifier is proposed. The characteristic size of the channels is generally about 35 microns of depth. The numerical results indicate that the production and manipulation of microdrops are possible with passive device within a typical oscillators chamber of 2.25 mm diameter and 0.20 mm length when the Reynolds number is Re = 490. The novel micro drops method that is presented in this study provides a simple solution about the production of microdrops problems in micro system. We undertake an experimental step. The first part is based on the realisation of sample oscillator; the second part is consisted of visualization, production and manipulation of microdrops.

Keywords: modelling, miscible, micro drops, production, oscillator sample, capillary

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Authors: A. Nourbakhsh

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A finite difference/front tracking method is used to study the motion of three-dimensional deformable drops suspended in plane Poiseuille flow at non-zero Reynolds numbers. A parallel version of the code was used to study the behavior of suspension on a reasonable grid resolution (grids). The viscosity and density of drops are assumed to be equal to that of the suspending medium. The effect of the Reynolds number is studied in detail. It is found that drops with small deformation behave like rigid particles and migrate to an equilibrium position about half way between the wall and the center line (the Segre-Silberberg effect). However, for highly deformable drops there is a tendency for drops to migrate to the middle of the channel, and the maximum concentration occurs at the center line. The effective viscosity of suspension and the fluctuation energy of the flow across the channel increases with the Reynolds number of the flow.

Keywords: suspensions, Poiseuille flow, effective viscosity, Reynolds number

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Authors: Shima Soleimani, Steven Eckels

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One area of special importance for the surface-level study of heat exchangers is tubes with internal micro-fins (< 0.5 mm tall). Micro-finned surfaces are a kind of extended solid surface in which energy is exchanged with water that acts as the source or sink of energy. Significant performance gains are possible for either shell, tube, or double pipe heat exchangers if the best surfaces are identified. The parametric studies of micro-finned tubes that have appeared in the literature left some key parameters unexplored. Specifically, they ignored three-dimensional (3D) micro-fin configurations, conduction heat transfer in the fins, and conduction in the solid surface below the micro-fins. Thus, this study aimed at implementing a parametric study of 3D micro-finned tubes that considered micro-fine height and discontinuity features. A 3D conductive and convective heat-transfer simulation through coupled solid and periodic fluid domains is applied in a commercial package, ANSYS Fluent 19.1. The simulation is steady-state with turbulent water flow cooling the inner wall of a tube with micro-fins. The simulation utilizes a constant and uniform temperature on the tube outer wall. Performance is mapped for 18 different simulation cases, including a smooth tube using a realizable k-ε turbulence model at a Reynolds number of 48,928. Results compared the performance of 3D tubes with results for the similar two-dimensional (2D) one. Results showed that the micro-fine height has a greater impact on performance factors than discontinuity features in 3D micro-fin tubes. A transformed 3D micro-fin tube can enhance heat transfer, and pressure drops up to 21% and 56% compared to a 2D one, respectfully.

Keywords: three-dimensional micro-fin tube, heat transfer, friction factor, heat exchanger

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Authors: R. Burahee, B. Chassinat, T. de Laclos, A. Dépée, A. Sastim

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The purpose of this paper is to propose a solution to detect, predict and reconstitute rain drops in real time – during the night – using an embedded material with an infrared camera. To prevent the system from needing too high hardware resources, simple models are considered in a powerful image treatment algorithm reducing considerably calculation time in OpenCV software. Using a smart model – drops will be matched thanks to a process running through two consecutive pictures for implementing a sophisticated tracking system. With this system drops computed trajectory gives information for predicting their future location. Thanks to this technique, treatment part can be reduced. The hardware system composed by a Raspberry Pi is optimized to host efficiently this code for real time execution.

Keywords: reconstitution, prediction, detection, rain drop, real time, raspberry, infrared

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Authors: Fatiha Aouabed, Abdelhafid Bayadi, Rabah Boudissa

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Nowadays, silicone rubber insulation materials are widely used in high voltage outdoor insulation systems as they can combat pollution flashover problems. The difference in pollution flashover performance of silicone rubber and other insulating materials is due to the way that water wets their surfaces. It resides as discrete drops on silicone rubber, and the mechanism of flashover is due to the breakdown of the air between the water drops and the distortion of these drops in the direction of the electric field which brings the insulation to degradation and failure. The main objective of this work is to quantify the effect of different types of water drops arrangements, their position and dry bands width on the flashover voltage of the silicone insulating surface with non-uniform electric field systems. The tests were carried out on a rectangular sample under AC voltage. A rod-rod electrode system is used. The findings of this work indicate that the performance of the samples decreases with the presence of water drops on their surfaces. Further, these experimental findings show that there is a limiting number of rows from which the flashover voltage of the insulation is minimal and constant. This minimum is a function of the distance between two successive rows. Finally, it is concluded that the system withstand voltage increases when the row of droplets on the electrode axis is removed.

Keywords: contamination, flashover, testing, silicone rubber insulators, surface wettability, water droplets

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Authors: Yu Chen, Weiwei Ren, Xiaojing Mu, Feng Zhang, Yi Xu

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The superhydrophobic surface is widely used to reduce friction for the flow inside micro-channel and can be used to control/manipulate fluid, cells and even proteins in lab-on-chip. Fabricating micro grooves on hydrophobic surfaces is a common method to obtain such superhydrophobic surface. This study utilized the numerical method to investigate the effect of eccentric micro-grooves on the friction of flow inside micro-channel. A detailed parametric study was conducted to reveal how the eccentricity of micro-grooves affects the micro-channel flow under different grooves sizes, channel heights, Reynolds number. The results showed that the superhydrophobic surface with eccentric micro-grooves induces less friction than the counter part with aligning micro-grooves, which means requiring less power for pumps.

Keywords: eccentricity, micro-channel, micro-grooves, superhydrophobic surface

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Authors: A. Guellati, F-M Lounis, N. Guemras, K. Daoud

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Micro droplet formation is considered as a growing emerging area of research due to its wide-range application in chemistry as well as biology. The mechanism of micro droplet formation using two immiscible liquids running through a T-junction has been widely studied. We believe that the flow of these two immiscible phases can be of greater important factor that could have an impact on out-flow hydrodynamic behavior, the droplets generated and the size of the droplets. In this study, the type of the capillary tubes used also represents another important factor that can have an impact on the generation of micro droplets. The tygon capillary tubing with hydrophilic inner surface doesn't allow regular out-flows due to the fact that the continuous phase doesn't adhere to the wall of the capillary inner surface. Teflon capillary tubing, presents better wettability than tygon tubing, and allows to obtain steady and regular regimes of out-flow, and the micro droplets are homogeneoussize. The size of the droplets is directly dependent on the flows of the continuous and dispersed phases. Thus, as increasing the flow of the continuous phase, to flow of the dispersed phase stationary, the size of the drops decreases. Inversely, while increasing the flow of the dispersed phase, to flow of the continuous phase stationary, the size of the droplet increases.

Keywords: microfluidic system, micro droplets generation, t-junction, fluids engineering

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Authors: Alexander Mikkelsen, Khobaib Khobaib, Zbigniew Rozynek

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Drops covered by particles have found important uses in various fields, ranging from stabilization of emulsions to production of new advanced materials. Particles at drop interfaces can be interlocked to form solid capsules with properties tailored for a myriad of applications. Despite the huge potential of particle-laden drops and capsules, the knowledge of their deformation and stability are limited. In this regard, we contribute with experimental studies on the deformation and manipulation of silicone oil drops covered with micrometer-sized particles subjected to electric fields. A mixture of silicone oil and particles were immersed in castor oil using a mechanical pipette, forming millimeter sized drops. The particles moved and adsorbed at the drop interfaces by sedimentation, and were structured at the interface by electric field-induced electrohydrodynamic flows. When applying a direct current electric field, free charges accumulated at the drop interfaces, yielding electric stress that deformed the drops. In our experiments, we investigated how particle properties affected drop deformation, break-up, and particle structuring. We found that by increasing the size of weakly-conductive clay particles, the drop shape can go from compressed to stretched out in the direction of the electric field. Increasing the particle size and electrical properties were also found to weaken electrohydrodynamic flows, induce break-up of drops at weaker electric field strengths and structure particles in chains. These particle parameters determine the dipolar force between the interfacial particles, which can yield particle chaining. We conclude that the balance between particle chaining and electrohydrodynamic flows governs the observed drop mechanics.

Keywords: drop deformation, electric field induced stress, electrohydrodynamic flows, particle structuring at drop interfaces

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Authors: M. Brik, S. Harmand, I. Zaaroura

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This report, an experimental investigation, concerns the sessile daughter drop remaining during the coalescence of water drops in a liquid-liquid (LL) system. The two drops are initially vertically aligned where the sessile drop is deposited on a chemically treated super-hydrophobic surface of a cube fill of silicone oil. In order to analyze the coalescence dynamics, a series of experiments have been performed using a generation droplets system (KRUSS) that measures contact angles as well coupled with a high-speed camera (Keyence VW-9000E) to record the process at a frame rate of 15000s-1. It’s depicted that in such configuration, the head drop volume has a primordial impact on the dynamics of the coalescence process, especially at the last stage. It’s found that for a sessile drop deposited on a super-hydrophobic surface, where the contact angle is about θ ≈ 145°, the coalescence process is remarked to be complete without any recoiling of the coalesced drop or a generation of a sessile daughter drop at the super-hydrophobic surface when the head drop volume is small enough (Vₐᵦ< Vₛ up to Vₐᵦ = 3Vₛ). On the other side, the coalescence process starts to be followed by jumping off the resulted drop as well as a remaining of a small sessile daughter drop on the bottom surface of the cube from a head drop volume Vₐᵦ of about 4 times than that of the sessile drop Vₛ.

Keywords: drops coalescence, dispersed multiphase flow, drops dynamics, liquid-liquid system

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Authors: Y. Haik

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The objective of this study is to present a micro mechanical pump that was fabricated using SwIFT™ microfabrication surface micromachining process and to demonstrate the feasibility of integrating such micro pump into a micro analysis system. The micropump circulates the bio-sample and magnetic nanoparticles through different compartments to separate and purify the targeted bio-sample. This article reports the flow characteristics in the microchannels and in a crescent micro pump.

Keywords: crescent micropumps, microanalysis, nanoparticles, MEMS

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Authors: Saber Fatourechian

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People within modern cities have faced macro urban values spreads rapidly through current style of living. Unexpected phenomena without any specific features of micro scale, humanity and urban social/cultural patterns. The gap between micro and macro scale is unidentified and people could not recognize where they are especially in the interaction between life and city. Urban life details were verified. Micro architecture is a pattern in which human activity derives from human needs in an unconscious position. Sustainable attitude via micro architecture causes flexibility in decision making through micro urbanism essentially impacts macro scale. In this paper the definition of micro architecture and its relation with city and human activity are argued, there after the interaction between micro and macro scale is presented as an effective way for urban sustainable development.

Keywords: micro architecture, sustainability, human activity, city

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Authors: M. Ghanbari, S. Hossainpour, G. Rezazadeh

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In this paper, longitudinal vibration of a micro-beam in micro-scale fluid media has been investigated. The proposed mathematical model for this study is made up of a micro-beam and a micro-plate at its free end. An AC voltage is applied to the pair of piezoelectric layers on the upper and lower surfaces of the micro-beam in order to actuate it longitudinally. The whole structure is bounded between two fixed plates on its upper and lower surfaces. The micro-gap between the structure and the fixed plates is filled with fluid. Fluids behave differently in micro-scale than macro, so the fluid field in the gap has been modeled based on micro-polar theory. The coupled governing equations of motion of the micro-beam and the micro-scale fluid field have been derived. Due to having non-homogenous boundary conditions, derived equations have been transformed to an enhanced form with homogenous boundary conditions. Using Galerkin-based reduced order model, the enhanced equations have been discretized over the beam and fluid domains and solve simultaneously in order to obtain force response of the micro-beam. Effects of micro-polar parameters of the fluid as characteristic length scale, coupling parameter and surface parameter on the response of the micro-beam have been studied.

Keywords: micro-polar theory, Galerkin method, MEMS, micro-fluid

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Authors: Asmae Tafraouti, Yasmina Layouni

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The fabrication of cylindrical Tungsten micro-tools with a high aspect ratio is a real challenge because of several constraints that come into during their manufacture. In this paper, we will describe the process used to fabricate these micro-tools. It consists of using electrochemical etching. We will also present the optimal protocol that makes it possible to fabricate micro-tools with a high aspect ratio in a reproducible way. Next, we will show the limit of the experimental parameters chosen to manufacture micro-tools from a wire with an initial diameter of Φ_0=250µm. The protocol used allows obtaining an average diameter of Φ=88µm ±1 µm over a length of L=3.5mm.

Keywords: drop-off effect, electrochemical etching, micro-electrical discharge machining, tungsten micro-tools

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Authors: Reza Gheisari, Paulo J. Bartolo, Nicholas Goddard

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Polymeric micro-cantilevers (Cs) are rapidly becoming popular for MEMS applications such as chemo- and bio-sensing as well as purely electromechanical applications such as microrelays. Polymer materials present suitable physical and chemical properties combined with low-cost mass production. Hence, micro-cantilevers made of polymers indicate much more biocompatibility and adaptability of rapid prototyping along with mechanical properties. This research studies the effects of three process and one size factors on the filling behaviour in micro cavity, and the role of each in the replication of micro parts using different polymer materials i.e. polypropylene (PP) SABIC 56M10 and acrylonitrile butadiene styrene (ABS) Magnum 8434. In particular, the following factors are considered: barrel temperature, mould temperature, injection speed and the thickness of micro features. The study revealed that the barrel temperature and the injection speed are the key factors affecting the flow length of micro features replicated in PP and ABS. For both materials, an increase of feature sizes improves the melt flow. However, the melt fill of micro features does not increase linearly with the increase of their thickness.

Keywords: flow length, micro cantilevers, micro injection moulding, microfabrication

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Authors: Achmad Muchaddam Fahham, Sony Hendra Permana

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For rural communities and micro-entrepreneurs, access to formal financial institutions is very difficult. So, borrowing to moneylenders is the most possible way to fulfill their needs. But actually it does not solve their problems, precisely their problems are increasing because they have to pay at very high-interest rates. For this reason, microfinance institution is very important as a solution for rural communities and micro-entrepreneurs who need loans to fulfill their needs. This paper aims to describe the role of micro waqf banks in Indonesia as an alternative funding for rural communities and micro-entrepreneurs. This research is descriptive using a qualitative approach. The interview technique was also carried out with key informants who understood sharia microfinance institutions. The results of the study revealed that the micro waqf bank is Islamic microfinance institutions which targeted the micro business sector by channeling small financing with a maximum financing of Rp1 million. The funding of this micro waqf bank comes from donors who donate funds through the Amil Zakat institution. The margins imposed on borrowers are as high as 3 percent per year, with payment schemes in installments every week, so it is made easier for borrower. In addition, financing is followed by training and mentoring so that borrower is able to utilize the loan for productive business activities. In the end, it is hoped that this micro waqf bank can become an incubator for micro businesses in Indonesia.

Keywords: micro business, micro waqf banks, micro-entrepreneurs, Amil Zakat institution

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Authors: Ram Bikram Thapa, Ganesh Lama

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The Micro Hydro is one of the successful technology in Rural Nepal. Kavre is one of the pioneer district of sustainability of Micro Hydro Projects. A total of 30 Micro Hydro projects have been constructed with producing 700 KW of energy in northern side of the Kavre district. This study shows that 67% of projects have been affected by devastating earthquake in April and May, 2015. Out of them 23% are completely damaged. Most of the structures are failure like Penstock 71%, forebay 21%, powerhouse 7% have been completely damaged and 91% Canal & 44% Intake structures have been partially damaged by the earthquake. This paper empathizes that the engineering design is the vital component for sustainability of Micro Hydro Projects. This paper recommended that technicians should be considered the safety factor of earthquake and provision of disaster recovery fund during design of Micro Hydro Projects.

Keywords: micro hydro, earthquake, structural failure, sustainability

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Authors: B. S. Akhmetov, P. T.Kharitonov, L. Sh. Balgabayeva, O. V. Kisseleva, T. S. Kartbayev

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This article analyzes the applicability of known renewable energy technical means as mobile power sources under the field and extreme conditions. The requirements are determined for the parameters of mobile micro-HPP. The application prospectively of the mobile micro-HPP with intelligent control systems is proved for this purpose. Variants of low-speed electric generators for micro HPP are given. Variants of designs for mobile micro HPP are presented with the direct (gearless) transfer of torque from the hydraulic drive to the rotor of the electric generator. Variant of the hydraulic drive for micro HPP is described workable at low water flows. A general structure of the micro HPP intelligent system control is offered that implements the principle of maximum energy efficiency. The legitimacy of construction and application of mobile micro HPP is proved as electrical power sources for life safety of people under the field and extreme conditions.

Keywords: mobile micro-hydro powerplants, information management systems, hydraulic drive, computer science

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Authors: Liu Ziyu, Gao Yongfeng, Li Muhua, Zhao Jiahao, Meng Song

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The effect of thermal shock on the operation of micro electromechanical systems (MEMS) were examined. All MEMS device were tested before and after three different conditions of thermal shock (from -55℃ to 85℃, from -65℃ to 125℃, from -65℃ to 200℃). The micro lens showed no changes after thermal shock, which shows that the design of the micro lens can be well adapted to the application environment in the space. The design of the micro mirror can be well adapted to the space application environment. The micro-magnetometer, RF MEMS switch and the micro accelerometer exhibited degradation and parameter drift after thermal shock, potential mechanical was proposed.

Keywords: MEMS, thermal shock test, reliability, space environment

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Authors: Mehrdad Rezaei, Reza Haghmaram, Nima Amjadi

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This paper proposes an operating and cost optimization model for micro-grid (MG). This model takes into account emission costs of NOx, SO2, and CO2, together with the operation and maintenance costs. Wind turbines (WT), photovoltaic (PV) arrays, micro turbines (MT), fuel cells (FC), diesel engine generators (DEG) with different capacities are considered in this model. The aim of the optimization is minimizing operation cost according to constraints, supply demand and safety of the system. The proposed genetic algorithm (GA), with the ability to fine-tune its own settings, is used to optimize the micro-grid operation.

Keywords: micro-grid, optimization, genetic algorithm, MG

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Authors: Zhen Qin, Yufei Peng, Jianbei Li, Jidong Long

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In order to study the activity of the coated aluminate barium-tungsten cathodes during activation, aging, poisoning and long-term use. Through a set of hot-cathode micro-area emission uniformity study device, we tested the micro-area emission performance of the cathode under different conditions. The change of activity of cathode micro-area was obtained. The influence of micro-area activity on the performance of the cathode was explained by the ageing model of barium-tungsten cathode. This helps to improve the design and process of the cathode and can point the way in finding the factors that affect life in the cathode operation.

Keywords: barium-tungsten cathode, ageing model, micro-area emission, emission uniformity

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Authors: Zelikha Labbani

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The In Vitro isolated micro spore culture is the most powerful androgenic pathway to produce doubled haploid plants in the short time. To deviate a micro spore toward embryogenesis, a number of factors, different for each species, must concur at the same time and place. Once induced, the micro spore undergoes numerous changes at different levels, from overall morphology to gene expression. Induction of micro spore embryogenesis not only implies the expression of an embryogenic program, but also a stress-related cellular response and a repression of the gametophytic program to revert the microspore to a totipotent status. As haploid single cells, micro spore became a strategy to achieve various objectives particularly in genetic engineering. In this study we would show the most recent advances in the producing haploid embryos via In Vitro isolated micro spore culture.

Keywords: haploid cells, In Vitro isolated microspore culture, success

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Authors: Mohammad Tahmasebipour, Hosein Salarpour

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Micro cantilevers are one of the components used in the manufacture of micro-electromechanical systems. Epoxy microcantilevers have a variety of applications in the manufacture of micro-sensors and micro-actuators. In this paper, the Timoshenko Micro cantilever was statically and dynamically analyzed using the finite element method. First, all boundary conditions and initial conditions governing micro cantilevers were considered. The effect of size on the deflection, angle of rotation, natural frequencies, and mode shapes were then analyzed and evaluated under different frequencies. It was observed that an increased micro cantilever thickness reduces the deflection, rotation, and resonant frequency. A good agreement was observed between our results and those obtained by the couple stress theory, the classical theory, and the strain gradient elasticity theory.

Keywords: microcantilever, microsensor; epoxy, dynamic behavior, static behavior, finite element method

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Authors: Ali Hamad, Ibrahim Al-Drous, Saleh Al-Jufout

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This paper presents a case study of using STATCOM to enhance the performance of Al-Qatraneh 33-kV transmission line. The location of the STATCOM was identified maintaining minimum voltage drops at the 110 load nodes. The transmission line and the 110 load nodes have been modeled by MATLAB/Simulink. The suggested STATCOM and its location will increase the transmission capability of this transmission line and overcome the overload expected in the year 2020. The annual percentage loading rise has been considered as 14%. A graphical representation of the line voltages and the voltage drops at different load nodes has been illustrated.

Keywords: FACTS, MATLAB, STATCOM, transmission line, voltage drop

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Authors: Naveen Kumar Challa, Pavan Verıkıcherla, Madhubalan, Ashısh Sharma

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Aim: Aim of the study was to find whether any difference exists in pupil mydriasis measured with Orbscan in non-diabetic and type 2 diabetic patients at various intervals after installation of Tropicamide 0.8% and Phenylephrine 5%. Methods: the Observational study conducted at a tertiary care eye hospital during September 2014 to March 2015. 240 eyes from 120 patients (40 non-diabetic, 80 diabetic) were dilated with Tropicamide 0.8% and Phenylephrine 5%. One drop of a drug was installed twice. The second drop is installed at 20 minutes after installation of the first drop. In two groups’ pupil diameter was measured before installation of drops and also at 15, 30, 45 and 60 minutes after installation of the first drop using both Orbscan. Result: Mean age of the non-diabetic group is 48.67 ± 7.93 years; Diabetic group is 59.97 ± 8.77 years. Mean duration of Diabetes was 7.01 ± 5.05 years. Mean pupil diameter measured with Orbscan before installation of the drops and also at 15, 30, 45 and 60 minutes after installation of first drop in non-diabetic group was 4.18 ± 0.64mm, 6.15 ± 0.41mm, 7.76 ±0.34, 9.59 ± 0.30, and 9.97 ± 0.10 mm respectively and for the diabetic group it was 4.00 ± 0.56 mm, 5.53 ± 0.52 mm, 7.018 ± 0.58mm, 8.25±0.51mm and 9.18 ± 0.46mm respectively. The mean difference between the mean pupil diameters of the non-diabetic and diabetic group shows a significant difference (P< 0.01) at all intervals except before dilatation. There is a significant negative correlation (r = 0.78 – 0.92) between the duration of diabetes and pupil dilatation at all intervals after installation of the drops. There is also significant difference (P< 0.005) in the mean values of pupil diameter between non retinopathy diabetic subjects and diabetic retinopathy subjects at all intervals after installation of drops. Conclusion: People attending eye clinic, whose pupil mydriasis values falls below the normal may be referred for diabetic evaluation. If normative data is established for the pupil size in Indian population using Orbscan then the values fall under normative data could be a predictor for diabetes. This would in turn help ophthalmologist to detect the diabetes at an early stage and prevent the complications resulting from the diabetes.

Keywords: diabetes mellitus, pupil diameter, orbscan, tropicamide

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Authors: Benyamina, Ouldabess, Bensalah

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The aim of this study is to use membrane technique for filtration of a coloring solution. the preparation of the micro-filtration membranes is based on a natural clay powder with a low cost, deposited on macro-porous ceramic supports. The micro-filtration membrane provided a very large permeation flow. Indeed, the filtration effectiveness of membrane was proved by the total discoloration of bromothymol blue solution with initial concentration of 10-3 mg/L after the first minutes.

Keywords: the inorganic membrane, micro-filtration, coloring solution, natural clay powder

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Authors: Ahmad N. Shuid, Azri Jalil, Sabarul A. Mokhtar, Mohd F. Khamis, Norliza Muhammad

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Micro-CT provides a 3-D image of fracture callus, which can be used to calculate quantitative parameters. In this study, micro-CT was used to assess the fracture healing of orchidectomised rats, an androgen-deficient osteoporosis model. The effect of testosterone (hormone replacement) on fracture healing was also assessed with micro-CT. The rats were grouped into orchidectomised-control (ORX), sham-operated (SHAM), and orchidectomised; and injected with testosterone intramuscularly once weekly (TEN). Treatment duration was six weeks. The fracture was induced and fixed with plates and screws in the right tibia of all the rats. An in vitro micro-CT was used to scan the fracture callus area which consisted of 100 axial slices above and below fracture line. The analysis has shown that micro-CT was able to detect a significant difference in the fracture healing rate of ORX and TEN groups. In conclusion, micro-CT can be used to assess fracture healing in androgen-deficient osteoporosis. This imaging tool can be used to test agents that influence fracture healing in the androgen-deficient model.

Keywords: androgen, fracture, orchidectomy, osteoporosis

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Authors: M. Naveed Iqbal, Sheza Fatima, Noman Shabbir

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In the presence of energy crisis in Pakistan, off-grid remote areas are not on priority list. The use of new large scale coal fired power plants will also make this situation worst. Therefore, the greatest challenge in our society is to explore new ways to power off grid remote areas with renewable energy sources. It is time for a sustainable energy policy which puts consumers, the environment, human health, and peace first. The renewable energy is one of the biggest growing sectors of the energy industry. Therefore, the large scale use of micro grid is thus described here with modeling, simulation, planning and operating of the micro grid. The goal of this research paper is to go into detail of a library of major components of micro grid. The introduction will go through the detail view of micro grid definition. Then, the simulation of Micro Grid in MATLAB/ Simulink including the Photo Voltaic Cell will be described with the detailed modeling. The simulation with the design and modeling will be introduced too.

Keywords: micro grids, distribution generation, PV, off-grid operations

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Authors: Brahim Dennai, Abdelhak Bentaleb, Rachid Khelfaoui, Asma Abdenbi

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The diffusion flux given by the Fick’s law characterizethe mixing rate. A passive mixing strategy is proposed to enhance mixing of two fluids through perturbed jet low. A numerical study of passive mixers has been presented. This paper is focused on the modeling of a micro-injection systems composed of passive amplifier without mechanical part. The micro-system modeling is based on geometrical oscillators form. An asymmetric micro-oscillator design based on a monostable fluidic amplifier is proposed. The characteristic size of the channels is generally about a few hundred of microns. The numerical results indicate that the mixing performance can be as high as 99 % within a typical mixing chamber of 0.20 mm diameter inlet and 2.0 mm distance of nozzle - spliter. In addition, the results confirm that self-rotation in the circular mixer significantly enhances the mixing performance. The novel micro mixing method presented in this study provides a simple solution to mixing problems in microsystem for application in chemistry.

Keywords: micro oscillator, modeling, micro mixture, diffusion, size effect, chemical equation

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Authors: Salah Gariani, Islam Shyha, Fawad Inam, Dehong Huo

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A controlled cutting fluid impinging supply system (CUT-LIST) was developed to deliver an accurate amount of cutting fluid into the machining zone via well-positioned coherent nozzles based on a calculation of the heat generated. The performance of the CUT-LIST was evaluated against a conventional flood cutting fluid supply system during step shoulder milling of Ti-6Al-4V using vegetable oil-based cutting fluid. In this paper, the micro-hardness of the machined surface was used as the main criterion to compare the two systems. CUT-LIST provided significant reductions in cutting fluid consumption (up to 42%). Both systems caused increased micro-hardness value at 100 µm from the machined surface, whereas a slight reduction in micro-hardness of 4.5% was measured when using CUL-LIST. It was noted that the first 50 µm is the soft sub-surface promoted by thermal softening, whereas down to 100 µm is the hard sub-surface caused by the cyclic internal work hardening and then gradually decreased until it reached the base material nominal hardness. It can be concluded that the CUT-LIST has always given lower micro-hardness values near the machined surfaces in all conditions investigated.

Keywords: impinging supply system, micro-hardness, shoulder milling, Ti-6Al-4V, vegetable oil-based cutting fluid

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Authors: Noorulain Khalid, Unsaar Hayat, Muhammad Chaudhary, Christos Iosifidis, Felipe Dhawahir-Scala, Fiona Carley

Abstract:

Dry eye disease (DED) is a common condition seen in the emergency eye department (EED) at Manchester Royal Eye Hospital (MREH). However, there is variability in the prescription of lubricating eye drops among different healthcare providers. The aim of this study was to develop an up-to-date, standardized algorithm for the prescription of lubricating eye drops in the EED at MREH based on international and national guidelines. The study also aimed to assess the impact of implementing the guideline on the rate of inappropriate lubricant prescriptions. Primarily, the impact was to be assessed in the form of the appropriateness of prescriptions for patients’ DED. The impact was secondary to be assessed through analysis of the cost to the hospital. Data from 845 patients who attended the EED over a 3-month period were analyzed, and 157 patients met the inclusion and exclusion criteria. After conducting a review of the literature and collaborating with the corneal team, an algorithm for the prescription of lubricants in the EED was developed. Three plan-do-study-act (PDSA) cycles were conducted, with interventions such as emails, posters, in-person reminders, and education for incoming trainees. The appropriateness of prescriptions was evaluated against the guidelines. Data were collected from patient records and analyzed using statistical methods. The appropriateness of prescriptions was assessed by comparing them to the guidelines and by clinical correlation with a specialized registrar. The study found a substantial improvement in the number of appropriate prescriptions, with an increase from 55% to 93% over the three PDSA cycles. There was additionally a 51% reduction in expenditure on lubricant prescriptions, resulting in cost savings for the hospital (approximate saving of £50/week). Theoretical importance: Appropriate prescription of lubricating eye drops improves disease management for patients and reduces costs for the hospital. The development and implementation of a standardized guideline facilitate the achievement of these goals. Conclusion: This study highlights the inconsistent management of DED in the EED and the potential lack of training in this area for healthcare providers. The implementation of a standardized, easy-to-follow guideline for lubricating eye drops can help to improve disease management while also resulting in cost savings for the hospital.

Keywords: lubrication, dry eye disease, guideline, prescription

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