Search results for: the alternating current

Authors: Khaled M. El-Naggar

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This paper presents a fast and efficient technique for monitoring and supervising power system disturbances generated due to dynamic performance of power systems or faults. Monitoring power system quantities involve monitoring fundamental voltage, current magnitudes, and their frequencies as well as their negative and zero sequence components under different operating conditions. The proposed technique is based on simulated annealing optimization technique (SA). The method uses digital set of measurements for the voltage or current waveforms at power system bus to perform the estimation process digitally. The algorithm is tested using different simulated data to monitor the symmetrical components of power system waveforms. Different study cases are considered in this work. Effects of number of samples, sampling frequency and the sample window size are studied. Results are reported and discussed.

Keywords: estimation, faults, measurement, symmetrical components

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Authors: Boudjema Nouara, Mameri Nabil

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Bacteria have played an important role in water contamination as a consequence of organic pollution. In this study, an electrocoagulation process was adopted to remove fecal contamination and pathogenic bacteria from waste water. The effect of anode/cathodes materials as well as operating conditions for bacteria removal from water, such as current intensity and initial pH and temperature. The results indicated that the complete removal was achevied when using aluminium anode as anode at current intensity of 3A, initial pH of 7-8 and electrolysis time of 30 minutes. This process showed a bactericidal effect of 95 to 99% for the total and fecal coliforms and 99% to 100% for Eschercichia coli and fecal Streptococci. A decrease of 72% was recorded for sulphite-reducing Clostridia. Thus, this process has the potential to be one the options for treatment where high amount of bacteria in wastewater river.

Keywords: bacteria, el Harrach river, electrocoagulation, wastewater, treatment

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Authors: Ali Moarrefzadeh

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In metalworking, rolling is a metal forming process in which metal stock is passed through a pair of rolls. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is termed as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is termed as cold rolling. In terms of usage, hot rolling processes more tonnage than any other manufacturing process, and cold rolling processes the most tonnage out of all cold working processes. This article describes the use of advanced tubing inspection NDT methods for boiler and heat exchanger equipment in the petrochemical industry to supplement major turnaround inspections. The methods presented include remote field eddy current, magnetic flux leakage, internal rotary inspection system and eddy current.

Keywords: hot forming, cold forming, metal, rolling, simulation

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Authors: Kyungeun Sung

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Upcycling is a process in which used materials are converted into something of higher value and/or quality in their second life. It has been increasingly recognised as one promising means to reduce material and energy use and also to engender sustainable production and consumption. For this reason and other foreseeable benefits, the concept of upcycling has received more attention from numerous researchers and business practitioners in recent years. This has been seen in the growing number of publications on this topic since the 1990s. However, the overall volume of literature dealing with upcycling is still low and no major review has been presented. Therefore, in order to further establish this field, this paper analyses and summarises the current body of literature on upcycling, focusing on different definitions, trends in practices, benefits, drawbacks and barriers in a number of subject areas and gives suggestions for future research by illuminating knowledge gaps in the area of upcycling.

Keywords: circular economy, cradle to cradle, sustainable production and consumption, upcycling, waste management

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Authors: Sivaraman Karthikeyan

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Due to rapidly developing power electronics devices and technologies such as power line communication or self-commutating converters, voltage and current distortion, as well as interferences, have increased in the frequency range of 2 kHz to 150 kHz; there is an urgent need for regulation of electromagnetic compatibility (EMC) standards in this frequency range. Measuring or testing compliance with emission and immunity limitations necessitates the use of precise, repeatable measuring methods. Appropriate filters to minimize the fundamental component and its harmonics below 2 kHz in the measuring signal would improve the measurement accuracy in this frequency range leading to better analysis. This paper discusses filter suggestions in the current measurement standard and proposes an infinite impulse response (IIR) filter design that is optimized for a low number of poles, strong fundamental damping, and high accuracy above 2 kHz. The new filter’s transfer function is delivered as a result. An analog implementation is derived from the overall design.

Keywords: supraharmonics, 2 kHz, 150 kHz, filter, analog filter

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Authors: Ava Zarif Sanayei, Mustafa Farjad-Fard, Mohammad-Reza Mohammadian-Behbahani, Leyli Ebrahimi, Sedigheh Sina

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The fabrication and testing of a low-cost air-filled ion chamber for X-ray dosimetry is studied. The chamber is made of a metal cylinder, a central wire, a BC517 Darlington transistor, a 9V DC battery, and a voltmeter in order to have a cost-effective means to measure the dose. The output current of the dosimeter is amplified by the transistor and then fed to the large internal resistance of the voltmeter, producing a readable voltage signal. The dose-response linearity of the ion chamber is evaluated for different exposure scenarios by the X-ray tube. kVp values 70, 90, and 120, and mAs up to 20 are considered. In all experiments, a solid-state dosimeter (Solidose 400, Elimpex Medizintechnik) is used as a reference device for chamber calibration. Each case of exposure is repeated three times, the voltmeter and Solidose readings are recorded, and the mean and standard deviation values are calculated. Then, the calibration curve, derived by plotting voltmeter readings against Solidose readings, provided a linear fit result for all tube kVps of 70, 90, and 120. A 99, 98, and 100% linear relationship, respectively, for kVp values 70, 90, and 120 are demonstrated. The study shows the feasibility of achieving acceptable dose measurements with a simplified setup. Further enhancements to the proposed setup include solutions for limiting the leakage current, optimizing chamber dimensions, utilizing electronic microcontrollers for dedicated data readout, and minimizing the impact of stray electromagnetic fields on the system.

Keywords: dosimetry, ion chamber, radiation detection, X-ray

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Authors: Sourour Chaabane, Davide Clematis, Marco Panizza

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This study investigates the oxidation of Erythrosine B (EB) food dye by a homogeneous electro-Fenton process using iron (II) sulfate heptahydrate as a catalyst, carbon felt as cathode, and Ti/RuO2. The treated synthetic wastewater contains 100 mg L⁻¹ of EB and has a pH = 3. The effects of three independent variables have been considered for process optimization, such as applied current intensity (0.1 – 0.5 A), iron concentration (1 – 10 mM), and stirring rate (100 – 1000 rpm). Their interactions were investigated considering response surface methodology (RSM) based on Doehlert design as optimization method. EB removal efficiency and energy consumption were considered model responses after 30 minutes of electrolysis. Analysis of variance (ANOVA) revealed that the quadratic model was adequately fitted to the experimental data with R² (0.9819), adj-R² (0.9276) and low Fisher probability (< 0.0181) for EB removal model, and R² (0.9968), adj-R² (0.9872) and low Fisher probability (< 0.0014) relative to the energy consumption model reflected a robust statistical significance. The energy consumption model significantly depends on current density, as expected. The foregoing results obtained by RSM led to the following optimal conditions for EB degradation: current intensity of 0.2 A, iron concentration of 9.397 mM, and stirring rate of 500 rpm, which gave a maximum decolorization rate of 98.15 % with a minimum energy consumption of 0.74 kWh m⁻³ at 30 min of electrolysis.

Keywords: electrofenton, erythrosineb, dye, response serface methdology, carbon felt

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Authors: Carlos A. Garcia-Mogollon, Juan C. Quintero-Diaz, Claudio Avignone-Rossa

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Clostridium saccharoperbutylacetonicum 1-4N (Csb 1-4N) is an industrial reference strain for Acetone-Butanol-Ethanol (ABE) fermentation. Csb 1-4N is a solventogenic clostridium and H₂ producer with a metabolic profile that makes it a good candidate for Bioelectrosynthesis System (BES). The aim of this study was to evaluate the electroactivity of Csb 1-4N by cyclic voltammetry technique (CV). The Bioelectrosynthesis fermentation (BES) started in a Triptone-Yeast extract (TY) medium with trace elements and vitamins, Complex Nitrogen Source (CNS), and bicarbonate (NaHCO₃, 4g/L) as a carbon source, run at -600mVAg/AgCl and adding 200uM NADH. The six BES batches were performed with different media composition with and without NADH, CNS, HCO₃⁻ , and applied potential. The CV was performed as three-electrode system: platinum slice working electrode (WE), nickel contra electrode (CE) and reference electrode Ag/AgCl (ER). CVs were run in a potential range of -0.7V to 0.7V vs. VAg/AgCl at a scan rate 10mV/s. A CV recorded using different NaHCO₃ concentrations (0.25; 0.5; 1.0; 4g/L) were obtained. BES fermentation samples were centrifuged (3000 rpm, 5min, 4C), and supernatant (7mL) was used. CVs were obtained for Csb1-4N BES culture cell-free supernatant at 0h, 24h, and 48h. The electrochemical analysis was carried out with a PalmSens 4.0 potentiostat/galvanostat controlled with the PStrace 5.7 software, and CVs curves were characterized by reduction and oxidation currents and reduction and oxidation peaks. The CVs obtained for NaHCO₃ solutions showed that the reduction current and oxidation current decreased as the NaHCO₃ concentration was decreased. All reduction and oxidation currents decreased until exponential growth stop (24h), independence of initial cathodic current, except in medium with trace elements, vitamins, and NaHCO3, in which reduction current was around half at 24h and followed decreasing at 48. In this medium, Csb1-4N did not grow, but pH was increased, indicating that NaHCO₃ was reduced as the reduction current decreased. In general, at 48h reduction currents did not present important changes between different mediums in BES cultures. In terms of intensities in the peaks (Ip) did not present important variations; except with Ipa and Ipc in BES culture with NaHCO₃ and NADH added are higher than peaks in other cultures. Based on results, cathodic and anodic currents changes were induced by NaHCO₃ reduction reactions during Csb1-4N metabolic activity in different BES experiments.

Keywords: clostridium saccharoperbutylacetonicum 1-4N, bioelectrosynthesis, carbon dioxide fixation, cyclic voltammetry

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Authors: Walter Bernhofer, Peter Haber, Tobias Mayer, Manfred Mayr, Markus Ziegler

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Current preventive maintenance measures are cost intensive and not efficient. With the available sensor data of state of the art internet of things devices new possibilities of automated data processing emerge. Current advances in data science and in machine learning enable new, so called predictive maintenance technologies, which empower data scientists to forecast possible system failures. The goal of this approach is to cut expenses in preventive maintenance by automating the detection of possible failures and to improve efficiency and quality of maintenance measures. Additionally, a centralization of the sensor data monitoring can be achieved by using this approach. This paper describes the approach of three students to define a reference architecture for a predictive maintenance solution in the internet of things domain with a connected smartphone app for service technicians. The reference architecture is validated by a case study. The case study is implemented with current Microsoft Azure cloud technologies. The results of the case study show that the reference architecture is valid and can be used to achieve a system for predictive maintenance execution with the cloud components of Microsoft Azure. The used concepts are technology platform agnostic and can be reused in many different cloud platforms. The reference architecture is valid and can be used in many use cases, like gas station maintenance, elevator maintenance and many more.

Keywords: case study, internet of things, predictive maintenance, reference architecture

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Authors: Bohuslava Juhasova, Igor Halenar, Martin Juhas

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The contribution deals with the current situation in modern manufacturing enterprises, which is affected by digital virtualization of different parts of the production process. The overview part of this article points to the fact, that wide informatization of all areas causes substitution of real elements and relationships between them with their digital, often virtual images, in real practice. Key characteristics of the systems implemented using digital twin technology along with essential conditions for intelligent products deployment were identified across many published studies. The goal was to propose a template for the production system realization using digital twin technology as a supplement to standardized concepts for Industry 4.0. The main resulting idea leads to the statement that the current trend of implementation of the new technologies and ways of communication between industrial facilities erases the boundaries between the real environment and the virtual world.

Keywords: communication, digital twin, Industry 4.0, simulation, virtualization

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Authors: Norshazmira Mat Azmi, Sayidal El Fatimah Masnan, Shatirah Akib

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Boundless renewable energy, such as tidal energy, tidal current energy, wave energy, thermal energy and chemical energy are covered and possessed by oceans. The hybrid system helps in improving the economic and environmental sustainability of renewable energy systems to fulfill the energy demand. The objective and concept of hybridizing renewable energy is to meet the desired system requirements, with the lowest value of the energy cost. This paper reviews applications of using hybrid power generation system for remote area. It also highlights the future directions to investigate the impacts of surface waves on turbine design and performance. The importance of understanding the site-specific wave conditions could also been explored.

Keywords: hybrid, marine current energy, tidal turbine, wave turbine

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Authors: Rosangliana Chawngthu, Ramkumar K. Thapa

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A model calculation of photoassisted field emission current (PFEC) by using transfer Hamiltonian method will be present here. When the photon energy is incident on the surface of the metals, such that the energy of a photon is usually less than the work function of the metal under investigation. The incident radiation photo excites the electrons to a final state which lies below the vacuum level; the electrons are confined within the metal surface. A strong static electric field is then applied to the surface of the metal which causes the photoexcited electrons to tunnel through the surface potential barrier into the vacuum region and constitutes the considerable current called photoassisted field emission current. The incident radiation is usually a laser beam, causes the transition of electrons from the initial state to the final state and the matrix element for this transition will be written. For the calculation of PFEC, transfer Hamiltonian method is used. The initial state wavefunction is calculated by using Kronig-Penney potential model. The effect of the matrix element will also be studied. An appropriate dielectric model for the surface region of the metal will be used for the evaluation of vector potential. FORTRAN programme is used for the calculation of PFEC. The results will be checked with experimental data and the theoretical results.

Keywords: photoassisted field emission, transfer Hamiltonian, vector potential, wavefunction

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Authors: Woosuk Lee

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We controlled the electron injection rate in inverted quantum dot light-emitting diode (QLED) by inserting PEIE layer between ZnO electron transport layer(ETL) and quantum dots(QDs) layer and successfully demonstrated high efficiency of QLEDs. The inverted QLED has the layer structure of ITO(cathode)/ ZnO NPs/PEIE/QDs/PEIE/P-TPD/MoO3/Al(anode). The PEIE between poly-TPD hole transport layer (HTL) and quantum dot emitting layer protects QD EML during HTL coating process and improves the surface morphology. In addition, the hole injection barrier is reduced by upshifting the valence band maximum (VBM) of QDs. An additional layer of PEIE was introduced between ZnO and QD to balance charge within QD emissive layer in device, which serves as an effective electron blocking layer without changing device operating condition such as turn-on voltage and emissive spectra. As a result, the optimized QLED with 5nm PEIE shows a ~36% improved current efficiency and external quantum efficiency (EQE) compared to the QLED without PEIE.(maximum current efficiency, and EQE are achieved 70cd/A and 17.3%, respectively). In particular, the maximum brightness of the optimized QLED dramatically improved by a factor of 2.3 relative to the QLED without PEIE. The main reasons for these QLED performance improvement are due to the suppressing the leakage current across the device and well confined exciton by inserting PEIE layers.

Keywords: quantum dot light-emitting diodes, interfacial layer, charge-injection balance, suppressing QD charging

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Authors: Abir Yahya, Hacen Dhahri, Khalifa Slimi

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The present paper deals with a numerical simulation of temperature field inside a solid oxide fuel cell (SOFC) components. The temperature distribution is investigated using a co-flow planar SOFC comprising the air and fuel channel and two-ceramic electrodes, anode and cathode, separated by a dense ceramic electrolyte. The Lattice Boltzmann method (LBM) is used for the numerical simulation of the physical problem. The effects of inlet temperature, anode thermal conductivity and current density on temperature distribution are discussed. It was found that temperature distribution is very sensitive to the inlet temperature and the current density.

Keywords: heat sources, Lattice Boltzmann method, solid oxide fuel cell, temperature

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Authors: Seval Yilmaz, Filiz Bayrakci Karel, Ali Savas Koparal

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Textile products produced by leather have been indispensable for human consumption. Various chemicals are used to enhance the durability of end-products in the processing of leather products. The wastewaters from the leather industry which contain these chemicals exhibit toxic effects on the receiving environment and threaten the natural ecosystem. In this study, leather industry wastewater (LIW), which has high loads of contaminants, was treated using advanced treatment techniques instead of conventional methods. During the experiments, the performance of electrochemical methods was investigated. During the electrochemical experiments, the performance of batch electrooxidation (EO) using boron-doped diamond (BDD) electrodes with monopolar configuration for removal of chemical oxygen demand (COD) from LIW were investigated. The influences of electrolysis time, current density (which varies as 5 mA/cm², 10 mA/cm², 20 mA/cm², 30 mA/cm², 50 mA/cm²) and initial pH (which varies as 3,80 (natural pH of LIW), 7, 9) on removal efficiency were investigated in a batch stirred cell to determine the best treatment conditions. The current density applied to the electrochemical reactors is directly proportional to the consumption of electric energy, so electrical energy consumption was monitored during the experiment. The best experimental conditions obtained in electrochemical studies were as follows: electrolysis time = 60 min, current density = 30.0 mA/cm², pH 7. Using these parameters, 53.59% COD removal rates for LIW was achieved and total energy consumption was obtained as 13.03 kWh/m³. It is concluded that electrooxidation process constitutes a plausible and developable method for the treatment of LIW.

Keywords: BDD electrodes, COD removal, electrochemical treatment, leather industry wastewater

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Authors: Min-Hao Wang, Shih-Chih Chen

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Recently, the merits such as simple structure, low power consumption, and compatibility with complementary metal oxide semiconductor (CMOS) process give an advantage of resistive random access memory (RRAM) as a promising candidate for the next generation memory， hafnium dioxide (HfO2) has been widely studied as an oxide layer material, but the use of copper (Cu) as both top and bottom electrodes has rarely been studied. In this study, radio frequency sputtering was used to deposit the intermediate layer HfO₂, and electron beam evaporation was used. For the upper and lower electrodes (cu), using different AR: O ratios, we found that the control of the metal filament will make the filament widely distributed, causing the current to rise to the limit current during Reset. However, if the flow ratio is controlled well, the ON/OFF ratio can reach 104, and the set voltage is controlled below 3v.

Keywords: RRAM, metal filament, HfO₂, Cu electrode

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Authors: V. Srikanth, K. Balasubramanian, Rajath R. Bhat, A. S. Arjun, Nandhu Venugopal, Ananthu Unnikrishnan

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Indirect vector control is known to produce high performance in Permanent Magnet Synchronous Motor (PMSM) drives by decoupling flux and torque producing current components of stator current. The most commonly used controller or the vector control of AC motor is Proportional-Integral (P-I) controller. However, the P-I controller has some disadvantages such as high starting overshoot, sensitivity to controller gains and slower response to sudden disturbance. Therefore, the Integral-Proportional controller for PMSM drives to overcome the disadvantages of the P-I controller. Simulations results are presented and analyzed for both controllers and it is observed that Integral-Proportional (I-P) controllers give better responses than the traditional P-I controllers.

Keywords: PMSM, FOC, PI controller, IP controller

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Authors: Yosra Ben Mhamed

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Most previous research that investigates the importance of earnings volatility for a firm’s value has focused on the effects of earnings volatility on the cost of capital. Many study illustrate that earnings volatility can reduce the firm’s value by enhancing the cost of capital. However, a few recent studies directly examine the relation between earnings volatility and subsequent earnings levels. In our study, we further explore the role of volatility in forecasting. Our study makes two primary contributions to the literature. First, taking into account the level of current firm’s performance, we provide causal theory to the link between volatility and earnings predictability. Nevertheless, previous studies testing the linearity of this relationship have not mentioned any underlying theory. Secondly, our study contributes to the vast body of fundamental analysis research that identifies a set of variables that improve valuation, by showing that earnings volatility affects the estimation of future earnings. Projections of earnings are used by valuation research and practice to derive estimates of firm value. Since we want to examine the impact of volatility on earnings predictability, we sort the sample into three portfolios according to the level of their earnings volatility in ascending order. For each quintile, we present the predictability coefficient. In a second test, each of these portfolios is, then, sorted into three further quintiles based on their level of current earnings. These yield nine quintiles. So we can observe whether volatility strongly predicts decreases on earnings predictability only for highest quintile of earnings. In general, we find that earnings volatility has an inverse relationship with earnings predictability. Our results also show that the sensibility of earnings predictability to ex-ante volatility is more pronounced among profitability firms. The findings are most consistent with overinvestment and persistence explanations.

Keywords: earnings volatility, earnings predictability, earnings persistence, current profitability

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Authors: Betselot Girma Argaw

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The health of people living in rural areas of Ethiopia depends a lot on how good their water and sanitation systems are. Even though there have been efforts to improve these systems, many communities still struggle to get clean water and proper sanitation, which leads to many health problems and unfair conditions. This research looks into the current situation of water and sanitation in rural Ethiopia, focusing on the main challenges that stop these communities from having safe and lasting solutions. By studying current practices, policies, and infrastructure, this paper highlights the areas that need urgent attention. It also reviews successful examples and suggests recommendations that fit the local context. The goal is to offer practical ideas that can help create better strategies to improve the lives of millions of rural Ethiopians, aiming for lasting improvements in water and sanitation in these vulnerable areas.

Keywords: rural Ethiopia water, sanitation infrastructure, sustainable solutions, water accessibility

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Authors: Fahad Alamoudi, Yaser Miaji

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The growing popularity of swimming pools and other activities in the water for sport, fitness, therapy or just enjoyable relaxation have led to the increased use of swimming pools and the establishment of a variety of specific-use pools such as spa pools, water slides, and more recently, hydrotherapy and wave pools. In this research, a few simple equipment is used for test, detect and alert for detection of water cleanness and pollution. YSI Photometer Systems, TDSTestr High model, Rio 12HF and Electrode A1. The researchers used electrolysis as a method of separating bonded elements and compounds by passing an electric current through them. The results which use 41 experiments show the higher the salt concentration, the more efficient the electrode and the smaller the gap between the plates, the lower the electrode voltage. Furthermore, it is proved that the larger the surface area, the lower the cell voltage and the higher current used the more chlorine produced.

Keywords: photometer, electrode, electrolysis, swimming pool chlorination

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Authors: Lisa Tribuzio

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This paper explores the complexity of working with Muslim communities in Australia. It will draw upon the notions of belonging, social inclusion and effective community programming to engage Muslim communities in Western environments given the current global political climate. Factors taken into consideration for effective engagement include: family engagement, considering key practices such as Ramadan, fasting and prayer and food requirements, gender relations, core values around faith and spirituality, considering attitudes towards self disclosure in a counseling setting and the notion of Us and Them in the media and systems and its effect on minority communities. It will explore recent research in the field from Australian researchers as well as recommendations from United Nations in working with Muslim communities. It will also explore current practice models applied in Australia in engaging effectively with diverse communities and addressing racism and discrimination in innovative ways.

Keywords: Muslim, cultural diversity, social inclusion, racism

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Authors: Rafal Maciag

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Due to the development of the current civilization, one must create suitable models of its pervasive massive phenomena. Such a phenomenon is the digital transformation, which has a substantial number of disciplined, methodical interpretations forming the diversified reflection. This reflection could be understood pragmatically as the current temporal, a local differential state of knowledge. The model of the discursive space is proposed as a model for the analysis and description of this knowledge. Discursive space is understood as an autonomous multidimensional space where separate discourses traverse specific trajectories of what can be presented in multidimensional parallel coordinate system. Discursive space built on the world of facts preserves the complex character of that world. Digital transformation as a discursive space has a relativistic character that means that at the same time, it is created by the dynamic discourses and these discourses are molded by the shape of this space.

Keywords: complexity, digital transformation, discourse, discursive space, knowledge

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Authors: A. M. Tiara, Sudipto Chakraborty, S. K. Pal

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Impinging jets and their different configurations are important from the viewpoint of the fluid flow characteristics and their influence on heat transfer from metal surfaces due to their complex flow characteristics. Such flow characteristics results in highly variable heat transfer from the surface, resulting in varying cooling rates which affects the mechanical properties including hardness and strength. The overall objective of the current research is to conduct a fundamental investigation of the heat transfer mechanisms for an impinging coolant jet. Numerical simulation of the cooling process gives a detailed analysis of the different parameters involved even though employing Computational Fluid Dynamics (CFD) to simulate the real time process, being a relatively new research area, poses many challenges. The heat transfer mechanism in the current research is actuated by jet cooling. The computational tool used in the ongoing research for simulation of the cooling process is ANSYS Workbench software. The temperature and heat flux distribution along the steel strip with the effect of various flow parameters on the heat transfer rate can be observed in addition to determination of the jet impingement patterns, which is the major aim of the present analysis. Modelling both jet and air atomized cooling techniques using CFD methodology and validating with those obtained experimentally- including trial and error with different models and comparison of cooling rates from both the techniques have been included in this work. Finally some concluding remarks are made that identify some gaps in the available literature that have influenced the path of the current investigation.

Keywords: CFD, heat transfer, impinging jets, numerical simulation

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Authors: Jyun-Hao Liao, Chien-Ju Chen, Chia-Jui Yu, Meng Chyi Wu, Chia-Ching Wu

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In this letter, we reported the fabrication of InGaAs micro-photodiode sensor array with the rapid thermal diffusion (RTD) technique. The spin-on dopant source Zn was used to form the p-type region in InP layer. Through the RTD technique, the InP/InGaAs heterostructure was formed. We improved our fabrication on the p-i-n photodiode to micro size which pixel is 7.8um, and the pitch is 12.8um. The proper SiNx was deposited to form the passivation layer. The leakage current of single pixel decrease to 3.3pA at -5V, and 35fA at -10mV. The leakage current densities of each voltage are 21uA/cm² at -5V and 0.223uA/cm² at -10mV. As we focus on the wavelength from 0.9um to 1.7um, the optimized Si/Al₂O₃ bilayers are deposited to form the AR-coating.

Keywords: InGaAs, micro sensor array, p-i-n photodiode, rapid thermal diffusion, Zn diffusion

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Authors: Thomas Adi Purnomo Sidhi

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The importance of designing a pregnancy interactive information design for a mobile application is felt in order to assist pregnant women to get an easy access of highly credible pregnancy-related information on which often fail to be fulfilled, while it has been a very critical one. Thus, an observation of needs assessment for designing a pregnancy interactive information system design for a mobile application at iOS becomes current objective study. A comparative study of the top five pregnancy interactive information design available at the Apple Store conducted in order to fulfill it. Whilst, an observation of user experiences included for deeper analyzes. Moreover, a literature study conducted to support the arguments that being provided in the current study. The findings, surprisingly, also reveal the advantages of local wisdom in pregnancy that never been attached to those top five applications before.

Keywords: information system design, interactive design, local wisdom, pregnancy

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Authors: Ramadan Ahmed Abugeddida

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Libya is one of the third world countries, has a lot of natural resources, notably oil and gas, as well as attractive tourist sites, in addition to the vast area and diversity of the regions, oil is the main source of income in Libya, which was discovered in the sixties of the last century, which also contributed to the creation of some fundamental changes in the country's infrastructure, such as roads, hospitals, schools, airports, seaports, as well as factories. This paper focuses on airports as one of the most vital institutions in the country, linking the country to the outside world, where dealing with the current situation of airports, in terms of capabilities and infrastructure, as well as the level of services, in other words, to assess the current status of the airports and to identify strengths and weaknesses, as well as general description of the position and what can be done in the future for the advancement of this vital sector. This paper is a part of the doctoral thesis will be carried out by the researcher during the coming period entitled efficiency improvement through implementation of strategic quality management.

Keywords: airports, efficiency improvement, quality, strategy

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Authors: Linda Hassaine, Abdelhamid Mraoui, Mohamed Rida Bengourina

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In grid-connected photovoltaic systems, significant improvements can be carried out in the design and implementation of inverters: reduction of harmonic distortion, elimination of the DC component injected into the grid and the proposed control. This paper proposes a control strategy based on PWM switching patterns for an inverter for the photovoltaic system connected to the grid in order to control the injected current. The current injected must be sinusoidal with reduced harmonic distortion. An additional filter is designed to reduce high-order harmonics on the output side. This strategy exhibits the advantages: Simplicity, reduction of harmonics, the size of the line filter, reduction of the memory requirements and power calculation for the control.

Keywords: control, inverters, LCL filter, grid-connected photovoltaic system

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Authors: Hong Dongchen, Chen Qiuxiao, Wu Shuang

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Systematic science reveals the complex nonlinear mechanisms of behaviour in urban system. However, in China, when the current city planners face with the system, most of them are still taking simple linear thinking to consider the open complex giant system. This paper introduces the hyper-cycle theory, which is one of the basis theories of systematic science, based on the analysis of the reasons why the current urban planning failed, and proposals for optimization ideas that urban planning compilation should change, from controlling quantitative to the changes of relationship, from blueprint planning to progressive planning based on the nonlinear characteristics and from management control to dynamically monitor feedback.

Keywords: systematic science, hyper-cycle theory, urban planning, urban management

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Authors: Zahra R. Almansoor

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Background: Selective serotonin reuptake inhibitors (SSRI’s) and cognitive behavioural therapy (CBT) are the main treatment methods used for patients with obsessive compulsive disorder (OCD) under the National Institute of Health and Care Excellence (NICE) guidelines. Yet many patients are left with residual symptoms or remit, so several other therapeutic approaches have been explored. Objective: The objective was to systematically review the available literature regarding the treatment efficacy of current and potential approaches and diagnostic strategies. Method: First, studies were examined concerning diagnosis, prognosis, and influencing factors. Then, one reviewer conducted a systematic search of six databases using stringent search terms. Results of studies exploring the efficacy of treatment interventions were analysed and compared separately for adults and children. This review was limited to randomised controlled trials (RCT’s) conducted from 2016 onwards, and an improved Y-BOCS (Yale- Brown obsessive compulsive scale) score was the primary outcome measure. Results: Technology-based interventions including internet-based cognitive behavioural therapy (iCBT) were deemed as potentially effective. Discrepancy remains about the benefits of SSRI use past one year, but potential medication adjuncts include amantadine. Treatments such as association splitting and family and mindfulness strategies also have future potential. Conclusion: A range of potential therapies exist, either as treatment adjuncts to current interventions or as sole therapies. To further improve efficacy, it may be necessary to remodel the current NICE stepped-care model, especially regarding the potential use of lower intensity, cheaper treatments, including iCBT. Although many interventions show promise, further research is warranted to confirm this.

Keywords: family and group treatment, mindfulness strategies, novel treatment approaches, standard treatment, technology-based interventions

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Authors: Sarah Louise Cruz, Jemille Venturina

Abstract:

Ergonomics considers the capabilities and limitations of a person as they interact with tools, equipment, facilities and tasks in their work environment. Workplace is one example of physical work environment, be it a workbench or a desk. In school laboratories, sitting is the most common working posture of the students. Students maintain static sitting posture as they perform different computer-aided activities. The College of Engineering and College of Information and Communication Technology of a State University consist of twenty-two computer laboratories. Normally, students aren’t usually aware of the importance of sustaining proper sitting posture while doing their long hour computer laboratory activities. The study evaluates the perceived discomfort and working postures of students as they are exposed on current workplace design of computer laboratories. The current study utilizes Rapid Upper Limb Assessment (RULA), Body Discomfort Chart using Borg’s CR-10 Scale Rating and Quick Exposure Checklist in order to assess the posture and the current working condition. The result of the study may possibly minimize the body discomfort experienced by the students. The researchers redesign the individual workstations which includes working desk, sitting stool and other workplace design components. Also, the economic variability of each alternative was considered given that the study focused on improvement of facilities of a state university.

Keywords: computer workstation, ergonomics, posture, students, workplace

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