Search results for: simulated annealing technique (SA)

Authors: Yong Seo Koo, Jong Ho Nam, Yong Nam Choi, Dae Yeol Yoo, Jung Woo Han

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This paper presents a silicon controller rectifier (SCR) based ESD protection circuit for IC. The proposed ESD protection circuit has low trigger voltage and high holding voltage compared with conventional SCR ESD protection circuit. Electrical characteristics of the proposed ESD protection circuit are simulated and analyzed using TCAD simulator. The proposed ESD protection circuit verified effective low voltage ESD characteristics with low trigger voltage and high holding voltage.

Keywords: electro-static discharge (ESD), silicon controlled rectifier (SCR), holding voltage, protection circuit

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Authors: Ji-Hoon Byeon, Kwon-Hee Lee

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Strainer filter serves to block the inflow of impurities while mixed fluid is entering or exiting the piping. The filter of the strainer has a perforated structure, so that the pressure drop and the velocity change necessarily occur when the mixed fluid passes through the filter. It is possible to predict the pressure drop and velocity change of the strainer by numerical analysis by implementing all the perforated plates. However, if the size of the perforated plate exceeds a certain size, it is difficult to perform the numerical analysis, and sometimes we cannot guarantee its accuracy. In this study, we tried to predict the pressure drop and velocity change by using the porous media technique to obtain the equivalent resistance without actual implementation of the perforation shape of the strainer. Ansys-CFX, a commercial software, is used to perform the numerical analysis. The analysis procedure is as follows. Firstly, the unit pattern of the perforated plate is modeled, and the pressure drop is analyzed by varying the velocity by symmetry of the wall surface. Secondly, since the equation for obtaining resistance is a quadratic equation of pressure having unknown velocity, the viscous resistance and the inertia resistance of the perforated plate are obtained from the relationship between pressure and speed. Thirdly, by using the calculated resistance values, the values are substituted into the flat plate implemented as a two-dimensional porous media, and the accuracy is verified by comparing the pressure drop and the velocity change. Fourthly, the pressure drop and velocity change in the whole strainer are analyzed by using the resistance values obtained on the perforated plate in the actual whole strainer model. Using the porous media technique, it is found that pressure drop and velocity change can be predicted in relatively short time without modeling the overall shape of the filter. Acknowledgements: This work was supported by the Valve Center from the Regional Innovation Center(RIC) Program of Ministry of Trade, Industry & Energy (MOTIE).

Keywords: strainer, porous media, CFD, numerical analysis

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Authors: Eithan Hourie, Miki Malul, Raphael Bar-El

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To investigate the relationship between various welfare policies and the value of job security, we conducted a study with 201 people regarding their assessments of the value of job security with respect to three elements: income stability, assurance of continuity of employment, and security in the job. The experiment simulated different welfare policy scenarios, such as the amount and duration of unemployment benefits, workfare, and basic income. The participants evaluated the value of job security in various situations. We found that the value of job security is approximately 22% of the starting salary, which is distributed as follows: 13% reflects income security, 8.7% reflects job security, and about 0.3% is for being able to keep their current employment in the future. To the best of our knowledge, this article is one of the pioneers in trying to quantify the value of job security in different market scenarios and at varying levels of welfare policy. Our conclusions may help decision-makers when deciding on a welfare policy.

Keywords: job security value, employment protection legislation, status quo bias, expanding welfare policy

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Authors: Nauman A. Siddiqui

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High performance requirement of aircrafts and marines industry demands to cater major industrial problems like wetting, high-speed efficiency, and corrosion resistance. These problems can be resolved by producing the hydrophobic surfaces on the metal substrate. By anodization process, the surface of AA 7075 has been modified and achieved a rough surface with a porous aluminum oxide (Al2O3) structure at nano-level. This surface modification process reduces the surface contact energy and increases the liquid contact angle which ultimately enhances the anti-icing properties. Later the Silane and Polyurethane (PU) coatings on the anodized surface have produced a contact angle of 130°. The results showed a good water repellency and self-cleaning properties. Using SEM analysis, micrographs revealed the round nano-porous oxide structure on the substrate. Therefore this technique can help in increasing the speed efficiency by reducing the friction with the outer interaction and can also be declared as a green technique since it is user-friendly.

Keywords: AA 7075, hydrophobicity, silanes, polyurethane, anodization

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Authors: Ibrahim Watad, Ibrahim Abdulhalim

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Conventional spectroscopic surface plasmon resonance (SPR) sensors are widely used, both in fundamental research and environmental monitoring as well as healthcare diagnostics. However, they still lack the low limit of detection (LOD) and there still a place for improvement. SPR conventional sensors are based on the detection of a dip in the reflectivity spectrum which is relatively wide. To improve the performance of these sensors, many techniques and methods proposed either to reduce the width of the dip or to increase the sensitivity. Together with that, profiting from the sharp jump in the phase spectrum under SPR, several works suggested the extraction of the phase of the reflected wave. However, existing phase measurement setups are in general more complicated compared to the conventional setups, require more stability and are very sensitive to external vibrations and noises. In this study, a simple polarimetric technique for phase extraction under SPR is presented, followed by a theoretical error analysis and an experimental verification. The advantages of the proposed technique upon existing techniques will be elaborated, together with conclusions regarding the best polarimetric function, and its corresponding optimal metal layer range of thicknesses to use under the conventional Kretschmann-Raether configuration.

Keywords: plasmonics, polarimetry, thin films, optical sensors

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Authors: Deanna Ruano-Meas, Laura Shenkman

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Variances are seen in the way healthcare personnel (HCP) don and doff PPE risking contamination to self and others. By standardizing practice, variances in technique decrease, and so does the risk of contamination. To implement this change, the Model for Improvement will be used. A system change will be developed that will outline the role of the organizational leader’s support of HCP in the proper donning and doffing of PPE. Interventions will include environmental surveys to assess the safety and work situation ensuring a permissible environment, plan audits to confirm consistency, and the assessment of PPE wear for standardization. The change will also include an educational plan that will involve instruction of the current guidelines recommended by the Centers for Disease Control and Prevention (CDC) to all pertinent HCP, and the incorporation of PPE education in yearly educational training. The goal is a standardized practice and a reduced risk of contamination through education and organizational support. Personal protective equipment has had recent attention with the coming of the SARS-CoV-2. The realization that proper technique is important to decreasing contamination of pathogens has led to the revising of current processes.

Keywords: donning and doffing, HAI, infection control, PPE

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Authors: Younghoon Kim, Seoung Bum Kim

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One-class classification plays an important role in detecting outlier and abnormality from normal observations. In the previous research, several attempts were made to extend the scope of application of the one-class classification techniques to statistical process control problems. For most previous approaches, such as support vector data description (SVDD) control chart, the design of the control limits is commonly based on the assumption that the proportion of abnormal observations is approximately equal to an expected Type I error rate in Phase I process. Because of the limitation of the one-class classification techniques based on convex optimization, we cannot make the proportion of abnormal observations exactly equal to expected Type I error rate: controlling Type I error rate requires to optimize constraints with integer decision variables, but convex optimization cannot satisfy the requirement. This limitation would be undesirable in theoretical and practical perspective to construct effective control charts. In this work, to address the limitation of previous approaches, we propose the one-class classification algorithm based on the mixed integer programming technique, which can solve problems formulated with continuous and integer decision variables. The proposed method minimizes the radius of a spherically shaped boundary subject to the number of normal data to be equal to a constant value specified by users. By modifying this constant value, users can exactly control the proportion of normal data described by the spherically shaped boundary. Thus, the proportion of abnormal observations can be made theoretically equal to an expected Type I error rate in Phase I process. Moreover, analogous to SVDD, the boundary can be made to describe complex structures by using some kernel functions. New multivariate control chart applying the effectiveness of the algorithm is proposed. This chart uses a monitoring statistic to characterize the degree of being an abnormal point as obtained through the proposed one-class classification. The control limit of the proposed chart is established by the radius of the boundary. The usefulness of the proposed method was demonstrated through experiments with simulated and real process data from a thin film transistor-liquid crystal display.

Keywords: control chart, mixed integer programming, one-class classification, support vector data description

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Authors: R.M. Asyraf, A. Norazah, S.M. Khairuddin, B. Noraziah

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Designing a system at present requires a vital, challenging task; to ensure the design philosophy is maintained in economical ways. This paper perceived the value engineering (VE) approach applied in infrastructure works, namely stormwater drainage. This method is adopted in line as consultants have completed the detailed design. Function Analysis System Technique (FAST) diagram and VE job plan, information, function analysis, creative judgement, development, and recommendation phase are used to scrutinize the initial design of stormwater drainage. An estimated cost reduction using the VE approach of 2% over the initial proposal was obtained. This cost reduction is obtained from the design optimization of the drainage foundation and structural system, where the pile design and drainage base structure are optimized. Likewise, the design of the on-site detention tank (OSD) pump was revised and contribute to the cost reduction obtained. This case study shows that the VE approach can be an important tool in optimizing the design to reduce costs.

Keywords: value engineering, function analysis system technique, stormwater drainage, cost reduction

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Authors: F. Boudet, V. Galano, D. Gmira, L. Munoz, A. Reina

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Commodities pricing needs a specific approach as they are often linked to each other and so are expectedly doing their prices. They are called co-integrated when at least one stationary linear combination exists between them. Though widespread in economic literature, and even if many equilibrium relations and co-movements exist in the economy, this principle of co-movement is not developed in derivatives field. The present study focuses on the following problem: How can the price of a forward agreement on a commodity be simulated, when it is co-integrated with other ones? Theoretical analysis is developed from Gibson-Schwartz model and an analytical solution is given for short maturities contracts and under risk-neutral conditions. The application has been made to crude oil and heating oil energy commodities and result confirms the applicability of proposed method.

Keywords: co-integration, commodities, forward pricing, Gibson-Schwartz

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Authors: Agata M. Kołodziejczyk, Mateusz Harasymczuk, Pierre-Yves Girardin, Lucie Davidová

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Subjective time perception implies connection to cognitive functions, attention, memory and awareness, but a little is known about connections with homeostatic states of the body coordinated by circadian clock. In this paper, we present results from experimental study of subjective time perception in volunteers performing physical activity on treadmill in various phases of their circadian rhythms. Subjects were exposed to several time illusions simulated by programmed timing systems. This study brings better understanding for further improvement of of work quality in isolated areas. 

Keywords: biological clock, light, time illusions, treadmill

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Authors: Deepali Rastogi, Akanksha Rastogi

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Comfort and safety are two essential factors in a newborn’s clothing. Natural dyes are considered safe for infant clothes because they are non-toxic and have medicinal properties. Natural dyes are sensitive to pH and may show changes in hue under different pH conditions. Infant garments face treatments different than adult clothing, for instance, exposure to infant’s saliva, milk, and urine. The present study was designed to study the suitability of natural dyes for infant clothes. Cotton fabric was dyed using fifteen natural dyes and two mordants, alum, and ferrous sulphate. The dyed samples were assessed for colour fastness to washing, rubbing, perspiration and light. In addition, fastness to milk, saliva, and urine was also tested. Simulated solutions of saliva and urine were prepared for the study. For milk, one of the commercial formulations for infants was taken and used as per the directions. A wide gamut of colours was obtained after dyeing the cotton with different natural dyes and mordants. The colour strength of all the dyed samples was determined in terms of K/S values. Most of the ferrous sulphate mordanted dyes gave higher K/S values than alum mordanted samples. The wash fastness of dyed cotton fabrics ranged from 3/4 -5. Perspiration fastness test for the samples was done in both acidic and alkaline mediums. The ratings ranged from 3-5, with most of the dyes falling in the range of 4-5. The rubbing fastness of the dyed samples was tested in dry and wet conditions. The results showed excellent rub fastness ranging between 4-5. Light fastness was found to be good to moderate. The main food for infants is milk, and this becomes one of the main agents to spot infants' garments. All dyes showed excellent fastness properties against milk with a grey scale rating of 4-5. Fastness against saliva is recommended by various eco-labels, standards, and organizations for fabrics of infants or babies. The fastness of most of the dyes was found to be satisfactory against saliva. Infant garments get frequently soiled with urine. Most of the natural dyes on cotton fabric had good to excellent fastness to simulated urine. The grey scale ratings ranged from 3/4 – 5. Thus, it can be concluded that most of the natural dyes can be successfully used for infant wear and accessories and are fast to various liquids to which infant wear are exposed. Therefore, we can surround little ones with beautiful hues from nature's garden and clothe them in natural fibres dyed with natural dyes.

Keywords: fastness properties, infant wear, mordants, natural dyes

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Authors: G. Rajyalakhmi, C. Karthik, Gerson Desouza, Rimmie Duraisamy

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In this present work, metal matrix composites with combination of aluminium with (Sic/Al2O3) were fabricated using stir casting technique. The objective of the present work is to optimize the process parameters of Wire Electric Discharge Machining (WEDM) composites. Pulse ON Time, Pulse OFF Time, wire feed and sensitivity are considered as input process parameters with responses Material Removal Rate (MRR), Surface Roughness (SR) for optimization of WEDM process. Taguchi L18 Orthogonal Array (OA) is used for experimentation. Grey Relational Analysis (GRA) is coupled with Taguchi technique for multiple process parameters optimization. ANOVA (Analysis of Variance) is used for finding the impact of process parameters individually. Finally confirmation experiments were carried out to validate the predicted results.

Keywords: parametric optimization, particulate reinforced metal matrix composites, Taguchi-grey relational analysis, WEDM

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Authors: Salwa Mowafi, Mohamed Rehan, Hany Kafafy

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In this study, three different systems including room temperature, conventional water bath heating and microwave irradiation technique will be employed in the fabrication of silver nanoparticle-wool fibers. The silver nanoparticles will be synthesized in-situ incorporated into wool fibers under redox active bio-template of wool protein which facilitates the reduction of Ag+ to nanoparticulate Ag0. Silver NPs incorporated wool fiber will be characterized by scanning electron microscopy, energy dispersive X-ray, FTIR, TGA, silver content and X-ray photoelectron spectroscopy. The mechanism of binding Ag NPs in-situ incorporated wool fibers matrix will be discussed. The effect of silver nanoparticles on the coloration, antimicrobial, UV-protection and catalytic properties of the wool fibers will be evaluated. The overall results of this study indicate that the Ag NPs in-situ incorporated wool fibers will be applied as colorants for wool fibers with improving in its multi-functionality properties. So, this study provides a simple approach for innovative protein fibers design by applying the optical properties of Plasmonic noble metal nanoparticles.

Keywords: microwave irradiation technique, multi-functionality properties, silver nanoparticles, wool fibers

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Authors: Archana Thangavelu, Han-Ik Park, Young-Chul Park, Joon-Hong Park

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In this numerical study, we have proposed a method for evaluation of backward extrusion process of pressure vessel made up of steel. Demand for lighter and stiffer products have been increasing in the last years especially in automobile engineering. Through detailed finite element analysis, effective stress, strain and velocity profile have been obtained with optimal range. The process design of a forward and backward extrusion axe-symmetric part has been studied. Forging is mainly carried out because forged products are highly reliable and possess superior mechanical properties when compared to normal products. Performing computational simulations of 3D hot forging with various dimensions of billet and optimization of weight is carried out using Taguchi Orthogonal Array (OA) Optimization technique. The technique used in this study can be used for newly developed materials to investigate its forgeability for much complicated shapes in closed hot die forging process.

Keywords: backward extrusion, hot forging, optimization, finite element analysis, Taguchi method

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Authors: Bryan Clark B. Hernandez, Eugene C. Herrera, Kazuo Nadaoka

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Mangrove forests thriving in intertidal zones in tropical and subtropical regions of the world offer a range of ecosystem services including carbon storage and sequestration. They can regulate the detrimental effects of climate change due to carbon releases two to four times greater than that of mature tropical rainforests. Moreover, they are effective natural defenses against storm surges and tsunamis. However, their proliferation depends significantly on the prevailing hydroperiod at the coast. In the Philippines, these coastal ecosystems have been severely threatened with a 50% decline in areal extent observed from 1918 to 2010. The highest decline occurred in 1950 - 1972 when national policies encouraged the development of fisheries and aquaculture. With the intensive land use conversion upstream, changes in the freshwater-saltwater envelope at the coast may considerably impact mangrove growth conditions. This study investigates a developing urban watershed in Kalibo, Aklan province with a 220-hectare mangrove forest replanted for over 30 years from coastal mudflats. Since then, the mangrove forest was sustainably conserved and declared as protected areas. Hybrid land cover classification technique was used to classify Landsat images for years, 1990, 2010, and 2017. Digital elevation model utilized was Interferometric Synthetic Aperture Radar (IFSAR) with a 5-meter resolution to delineate the watersheds. Using numerical modelling techniques, the hydrologic and hydraulic analysis of the influence of land cover change to flow and sediment dynamics was simulated. While significant land cover change occurred upland, thereby increasing runoff and sediment loads, the mangrove forests abundance adjacent to the coasts for the urban watershed, was somehow sustained. However, significant alteration of the coastline was observed in Kalibo through the years, probably due to the massive land-use conversion upstream and significant replanting of mangroves downstream. Understanding the hydrologic-hydraulic response of these watersheds to change land cover is essential to helping local government and stakeholders facilitate better management of these mangrove ecosystems.

Keywords: coastal mangroves, hydrologic model, land cover change, Philippines

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Authors: Elmahdi Elgharbaoui, Tamou Nasser, Ahmed Essadki

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In the era of sustainable development, photovoltaic (PV) technology has shown significant potential as a renewable energy source. Photovoltaic generators (GPV) have a non-linear current-voltage characteristic, with a maximum power point (MPP) characterized by an optimal voltage, and depends on environmental factors such as temperature and irradiation. To extract each time the maximum power available at the terminals of the GPV and transfer it to the load, an adaptation stage is used, consisting of a boost chopper controlled by a maximum power point tracking technique (MPPT) through a stage of pulse width modulation (PWM). Our choice has focused on three techniques which are: the perturbation and observation method (P&O), the incremental conductance method (InCond) and the last is that of control using the fuzzy logic. The implementation and simulation of the system (photovoltaic generator, chopper boost, PWM and MPPT techniques) are then performed in the Matlab/Simulink environment.

Keywords: photovoltaic generator, technique MPPT, boost chopper, PWM, fuzzy logic, P&O, InCond

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Authors: M. Prema Kumar, P. Rajesh Kumar

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The increasing interest in image fusion (combining images of two or more modalities such as infrared and visible light radiation) has led to a need for accurate and reliable image assessment methods. This paper gives a novel approach of merging the information content from several videos taken from the same scene in order to rack up a combined video that contains the finest information coming from different source videos. This process is known as video fusion which helps in providing superior quality (The term quality, connote measurement on the particular application.) image than the source images. In this technique different sensors (whose redundant information can be reduced) are used for various cameras that are imperative for capturing the required images and also help in reducing. In this paper Image fusion technique based on multi-resolution singular value decomposition (MSVD) has been used. The image fusion by MSVD is almost similar to that of wavelets. The idea behind MSVD is to replace the FIR filters in wavelet transform with singular value decomposition (SVD). It is computationally very simple and is well suited for real time applications like in remote sensing and in astronomy.

Keywords: multi sensor image fusion, MSVD, image processing, monochrome video

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Authors: Fouzia Brihmat

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Economic planning models, which are used to build microgrids and distributed energy resources, are the current norm for expressing such confidence (DER). These models often decide both short-term DER dispatch and long-term DER investments. This research investigates the most cost-effective hybrid (photovoltaic-diesel) renewable energy system (HRES) based on Total Net Present Cost (TNPC) in an Algerian Saharan area, which has a high potential for solar irradiation and has a production capacity of 1GW/h. Lead-acid batteries have been around much longer and are easier to understand, but have limited storage capacity. Lithium-ion batteries last longer, are lighter, but generally more expensive. By combining the advantages of each chemistry, we produce cost-effective high-capacity battery banks that operate solely on AC coupling. The financial implications of this research describe the corrosion process that occurs at the interface between the active material and grid material of the positive plate of a lead-acid battery. The best cost study for the HRES is completed with the assistance of the HOMER Pro MATLAB Link. Additionally, during the course of the project's 20 years, the system is simulated for each time step. In this model, which takes into consideration decline in solar efficiency, changes in battery storage levels over time, and rises in fuel prices above the rate of inflation. The trade-off is that the model is more accurate, but it took longer to compute. As a consequence, the model is more precise, but the computation takes longer. We initially utilized the Optimizer to run the model without MultiYear in order to discover the best system architecture. The optimal system for the single-year scenario is the Danvest generator, which has 760 kW, 200 kWh of the necessary quantity of lead-acid storage, and a somewhat lower COE of $0.309/kWh. Different scenarios that account for fluctuations in the gasified biomass generator's production of electricity have been simulated, and various strategies to guarantee the balance between generation and consumption have been investigated. The technological optimization of the same system has been finished and is being reviewed in a recent paper study.

Keywords: battery, corrosion, diesel, economic planning optimization, hybrid energy system, lead-acid battery, multi-year planning, microgrid, price forecast, PV, total net present cost

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Authors: Valentina Paolucci, Jessica De Santis, Vittorio Ricci, Giacomo Giorgi, Carlo Cantalini

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Despite their potential in gas sensing applications, the major drawback of 2D exfoliated metal dichalcogenides (MDs) is that they suffer from spontaneous oxidation in air, showing poor chemical stability under dry/wet conditions even at room temperature, limiting their practical exploitation. The aim of this work is to validate a synthesis strategy allowing microstructural and electrical stabilization of the oxides that inevitably form on the surface of 2D dichalcogenides. Taking advantage of spontaneous oxidation of MDs in air, we report on liquid phase exfoliated 2D-SnSe2 flakes annealed in static air at a temperature below the crystallization temperature of the native a-SnO2 oxide. This process yields a new class of 2D Layered Amorphous Metal Oxides Sensors (LAMOS), specifically few-layered amorphous a-SnO2, showing excellent gas sensing properties. Sensing tests were carried out at low operating temperature (i.e. 100°C) by exposing a-SnO2 to both oxidizing and reducing gases (i.e. NO2, H2S and H2) and different relative humidities ranging from 40% to 80% RH. The formation of stable nanosheets of amorphous a-SnO2 guarantees excellent reproducibility and stability of the response over one year. These results pave the way to new interesting research perspectives out considering the opportunity to synthesize homogeneous amorphous textures with no grain boundaries, no grains, no crystalline planes with different orientations, etc., following gas sensing mechanisms that likely differ from that of traditional crystalline metal oxide sensors. Moreover, the controlled annealing process could likely be extended to a large variety of Transition Metal Dichalcogenides (TMDs) and Metal Chalcogenides (MCs), where sulfur, selenium, or tellurium atoms can be easily displaced by O2 atoms (ΔG < 0), enabling the synthesis of a new family of amorphous interfaces.

Keywords: layered 2D materials, exfoliation, lamos, amorphous metal oxide sensors

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Authors: Chijindu Okpalaoka, Charles Chinedu Onuselogu

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COVID-19, humanity's coronavirus disease caused by SARS-CoV-2, was first detected in late 2019 in Wuhan, China. COVID-19 lacked an established conventional pharmaceutical therapy, and as a result, the outbreak quickly became an epidemic affecting the entire World. Only a qPCR assay is reliable for diagnosing COVID-19. Clustered, regularly interspaced short palindromic repeats (CRISPR) technology is being researched for speedy and specific identification of COVID-19, among other therapeutic techniques. Apart from its therapeutic capabilities, the CRISPR technique is being evaluated to develop antiviral therapies; nevertheless, no CRISPR-based medication has been approved for human use to date. Prophylactic antiviral CRISPR in living being cells, a Cas 13-based approach against coronavirus, has been developed. While this method can be evolved into a treatment approach, it may face substantial obstacles in human clinical trials for licensure. This study discussed the potential applications of CRISPR-based techniques for developing a speedy and accurate feasible treatment alternative for the COVID-19 virus.

Keywords: COVID-19, CRISPR technique, Cas13, SARS-CoV-2, prophylactic antiviral

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Authors: V. P. Muhamed Shajudheen, K. Viswanathan, K. Anitha Rani, A. Uma Maheswari, S. Saravana Kumar

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We are reporting a simple and low-cost chemical precipitation method adopted to prepare zinc oxide nanoparticles (ZnO) using polyvinyl pyrrolidone (PVP) as a capping agent. The Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA) was applied on the dried gel sample to record the phase transformation temperature of zinc hydroxide Zn(OH)2 to zinc oxide (ZnO) to obtain the annealing temperature of 800C. The thermal, structure, morphology and optical properties have been employed by different techniques such as DSC-TGA, X-Ray Diffraction (XRD), Fourier Transform Infra-Red spectroscopy (FTIR), Micro Raman spectroscopy, UV-Visible absorption spectroscopy (UV-Vis), Photoluminescence spectroscopy (PL) and Field Effect Scanning Electron Microscopy (FESEM). X-ray diffraction results confirmed the wurtzite hexagonal structure of ZnO nanoparticles. The two intensive peaks at 160 and 432 cm-1 in the Raman Spectrum are mainly attributed to the first order modes of the wurtzite ZnO nanoparticles. The energy band gap obtained from the UV-Vis absorption spectra, shows a blue shift, which is attributed to increase in carrier concentration (Burstein Moss Effect). Photoluminescence studies of the single crystalline ZnO nanoparticles, show a strong peak centered at 385 nm, corresponding to the near band edge emission in ultraviolet range. The mixed shape of grapes, sphere, hexagonal and rock like structure has been noticed in FESEM. The results showed that PVP is a suitable capping agent for the preparation of ZnO nanoparticles by simple chemical precipitation method.

Keywords: ZnO nanoparticles, simple chemical precipitation route, mixed shape morphology, UV-visible absorption, photoluminescence, Fourier transform infra-Red spectroscopy

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Authors: Benoit Rougier, Alexandre Lefrancois, Herve Aubert

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Microwave interrogation in the range 10-100 GHz is identified as an advanced technique to investigate simultaneously shock and particle velocity measurements. However, it requires the understanding of electromagnetic wave propagation in a multi-layered moving media. The existing models limit their approach to wave guides or evaluate the velocities with a fitting method, restricting therefore the domain of validity and the precision of the results. Moreover, few data of permittivity on high explosives at these frequencies under dynamic compression have been reported. In this paper, shock and particle velocities are computed concurrently for steady and unsteady shocks for various inert and reactive materials, via a propagation model based on Doppler shifts and signal amplitude. Refractive index of the material under compression is also calculated. From experimental data processing, it is demonstrated that Hugoniot curve can be evaluated. The comparison with published results proves the accuracy of the proposed method. This microwave interrogation technique seems promising for shock and detonation waves studies.

Keywords: electromagnetic propagation, experimental setup, Hugoniot measurement, shock propagation

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Authors: Asma Ben Rhouma, Mahmoud Hamouda

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The delta inverter is considered as the reduced three-phase dc/ac converter topology. It contains only three two-quadrant power switches compared to six in the conventional one. This reduced power conversion topology is widely considered in many industrial applications, such as electric traction and large photovoltaic systems. This paper is focused on a new sinusoidal pulse width modulation algorithm (SPWM) developed for the delta inverter. As an unconventional inverter’s structure, irregular modulating functions waveforms of the SPWM switching technique are generated. The performances of the proposed SPWM technique was proven through computer simulations carried out on a delta inverter feeding a three-phase RL load. Digital Signal Processor (DSP) implementation of the novel SPWM algorithm have been realized on a laboratory prototype of the delta inverter feeding an RL load and a squirrel cage induction motor. Experimental results have highlighted its high performances under the proposed SPWM method.

Keywords: delta inverter, SPWM, simulation, DSP implementation

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Authors: Razali Bin Abidin

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This paper presents the development of a portable water jet cutter for soft materials such as meat. Twelve geometries of nozzles were simulated using finite element method. Water pressure was set to 1500 lb/in². Through the simulation, highest average water output speed was 133.04 m/s. The nozzle was fabricated from Al - alloy 5052 with the Factor of Safety~ 3. This indicates that the nozzle made of Al-alloy 5052 is capable of performing the cutting process without any fracture. Preliminary design of mobile water jet hand tool is presented at the end of this paper.

Keywords: water jet, finite element, Al-alloy 5052, nozzle geometry

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Authors: Tatyane Lopes de Freitas, Antonio Diogo S. Vieira, Susana Marta Isay Saad, Maria Ines Genovese

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The fruit processing industries generate a large volume of residues to produce juices, pulps, and jams. These residues, or by-products, consisting of peels, seeds, and pulps, are routinely discarded. Fruits are rich in bioactive compounds, including polyphenols, which have positive effects on health. Dry residues from two fruits, acerola (M. emarginata D. C.) and orange (C. sinensis), were characterized in relation to contents of ascorbic acid, minerals, total dietary fibers, moisture, ash, lipids, proteins, and carbohydrates, and also high performance liquid chromatographic profile of flavonoids, total polyphenols and proanthocyanidins contents, and antioxidant capacity by three different methods (Ferric reducing antioxidant power assay-FRAP, Oxygen Radical Absorbance Capacity-ORAC, 1,1-diphenyl-2-picrylhydrazil (DPPH) radical scavenging activity). Acerola by-products presented the highest acid ascorbic content (605 mg/100 g), and better antioxidant capacity than orange by-products. The dry residues from acerola demonstrated high contents of proanthocyanidins (617 µg CE/g) and total polyphenols (2525 mg gallic acid equivalents - GAE/100 g). Both presented high total dietary fiber (above 60%) and protein contents (acerola: 10.4%; orange: 9.9%), and reduced fat content (acerola: 1.6%; orange: 2.6%). Both residues showed high levels of potassium, calcium, and magnesium, and were considered sources of these minerals. With acerola by-product, four formulations of probiotics fermented milks were produced: F0 (without the addition of acerola residue (AR)), F2 (2% AR), F5 (5% AR) and F10 (10% AR). The physicochemical characteristics of the fermented milks throughout of storage were investigated, as well as the impact of in vitro simulated gastrointestinal conditions on flavonoids and probiotics. The microorganisms analyzed maintained their populations around 8 log CFU/g during storage. After the gastric phase of the simulated digestion, the populations decreased, and after the enteric phase, no colonies were detected. On the other hand, the flavonoids increased after the gastric phase, maintaining or suffering small decrease after enteric phase. Acerola by-products powder is a valuable ingredient to be used in functional foods because is rich in vitamin C, fibers and flavonoids. These flavonoids appear to be highly resistant to the acids and salts of digestion.

Keywords: acerola, orange, by-products, fermented milk

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Authors: K. Manmi, Q. X. Wang

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This paper investigates microbubble dynamics subject to ultrasound in a weakly viscous fluid near a rigid boundary. The phenomenon is simulated using a boundary integral method. The weak viscous effects are incorporated into the model through the normal stress balance across the bubble surface. The model agrees well with the Rayleigh-Plesset equation for a spherical bubble for several cycles. The effects of the fluid viscosity in the bubble dynamics are analyzed, including jet development, centroid movement and bubble volume.

Keywords: microbubble dynamics, bubble jetting, viscous effect, boundary integral method

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Authors: Himani Ratna Dahiya

Abstract:

This paper contributes to design a Wind Emulator coupled to 1.5 kW Induction generator for Wind Energy Conversion System. A wind turbine emulator (WTE) is important equipment for developing wind energy conversion systems. It offers a controllable test environment that allows the evaluation and improvement of control schemes for electric generators that is hard to achieve with an actual wind turbine since the wind speed varies randomly. In this paper a wind emulator is modeled and simulated using MATLAB. Verification of the simulation results is done by experimental setup using DC motor-Induction generator set, LABVIEW and data acquisition card.

Keywords: Wind Turbine Emulator, LABVIEW, matlab, induction generator

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Authors: Khelil Khadidja

Abstract:

In this paper, blackness of dark solitons is considered. The exact combination between nonlinearity and dispersion is responsible of solitons stability. Dark solitons get born when dispersion is abnormal and balanced by nonlinearity, at the opposite of brillant solitons which is born by normal dispersion and nonlinearity together. Thanks to their stability, dark solitons are suitable for transmission by optical fibers. Dark solitons which are a solution of Nonlinear Schrodinger equation are simulated with Matlab to discuss the influence of coefficient of blackness. Results show that there is a direct proportion between the coefficient of blackness and the intensity of dark soliton. Those gray solitons are stable and convenient for transmission.

Keywords: abnormal dispersion, nonlinearity, optical fiber, soliton

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Authors: Syahira Ibrahim, Herlina Abdul Rahim

Abstract:

The amylose content is an essential element in determining the texture and taste of rice grains. This paper evaluates the use of VIS-SWNIRS in estimating the amylose content for seven varieties of rice grains available in the Malaysian market. Each type consists of 30 samples and all the samples are scanned using the spectroscopy to obtain a range of values between 680-1000nm. The Savitzky-Golay (SG) smoothing filter is applied to each sample’s data before the Principal Component Regression (PCR) technique is used to examine the data and produce a single value for each sample. This value is then compared with reference values obtained from the standard iodine colorimetric test in terms of its coefficient of determination, R2. Results show that this technique produced low R2 values of less than 0.50. In order to improve the result, the range should include a wavelength range of 1100-2500nm and the number of samples processed should also be increased.

Keywords: amylose content, diffuse reflectance, Malaysia rice grain, principal component regression (PCR), Visible and Shortwave near-infrared spectroscopy (VIS-SWNIRS)

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Authors: Fatima Zohra Rahou, A. Guen Bouazza, B. Bouazza

Abstract:

Invention of transistor is the foundation of electronics industry. Metal Oxide Semiconductor Field Effect Transistor (MOSFET) has been the key for the development of nanoelectronics technology. In the first part of this manuscript, we present a new generation of MOSFET transistors based on SOI (Silicon-On-Insulator) technology. It is a partially depleted Silicon-On-Insulator (PD SOI MOSFET) transistor simulated by using SILVACO software. This work was completed by the presentation of some results concerning the influence of parameters variation (channel length L and gate oxide thickness Tox) on our PDSOI n-MOSFET structure on its drain current and kink effect.

Keywords: SOI technology, PDSOI MOSFET, FDSOI MOSFET, kink effect

Procedia PDF Downloads 262