Search results for: medium voltage
3459 Analysis of Structural and Photocatalytical Properties of Anatase, Rutile and Mixed Phase TiO2 Films Deposited by Pulsed-Direct Current and Radio Frequency Magnetron Co-Sputtering
Authors: S. Varnagiris, M. Urbonavicius, S. Tuckute, M. Lelis, K. Bockute
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Amongst many water purification techniques, TiO2 photocatalysis is recognized as one of the most promising sustainable methods. It is known that for photocatalytical applications anatase is the most suitable TiO2 phase, however heterojunction of anatase/rutile phases could improve the photocatalytical activity of TiO2 even further. Despite the relative simplicity of TiO2 different synthesis methods lead to the highly dispersed crystal phases and photocatalytic activity of the corresponding samples. Accordingly, suggestions and investigations of various innovative methods of TiO2 synthesis are still needed. In this work structural and photocatalytical properties of TiO2 films deposited by the unconventional method of simultaneous co-sputtering from two magnetrons powered by pulsed-Direct Current (pDC) and Radio Frequency (RF) power sources with negative bias voltage have been studied. More specifically, TiO2 film thickness, microstructure, surface roughness, crystal structure, optical transmittance and photocatalytical properties were investigated by profilometer, scanning electron microscope, atomic force microscope, X-ray diffractometer and UV-Vis spectrophotometer respectively. The proposed unconventional two magnetron co-sputtering based TiO2 film formation method showed very promising results for crystalline TiO2 film formation while keeping process temperatures below 100 °C. XRD analysis revealed that by using proper combination of power source type and bias voltage various TiO2 phases (amorphous, anatase, rutile or their mixture) can be synthesized selectively. Moreover, strong dependency between power source type and surface roughness, as well as between the bias voltage and band gap value of TiO2 films was observed. Interestingly, TiO2 films deposited by two magnetron co-sputtering without bias voltage had one of the highest band gap values between the investigated films but its photocatalytic activity was superior compared to all other samples. It is suggested that this is due to the dominating nanocrystalline anatase phase with various exposed surfaces including photocatalytically the most active {001}.Keywords: films, magnetron co-sputtering, photocatalysis, TiO₂
Procedia PDF Downloads 1133458 Characterization of High Phosphorus Gray Iron for the Stub- Anode Connection in the Aluminium Reduction Cells
Authors: Mohamed M. Ali, Adel Nofal, Amr Kandil, Mahmoud Agour
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High phosphorus gray iron (HPGI) is used to connect the steel stub of an anode rod to a prebaked anode carbon block in the aluminium reduction cells. In this paper, a complete characterization for HPGI was done, includes studying the chemical composition of the HPGI collar, anodic voltage drop, collar temperature over 30 days anode life cycle, microstructure and mechanical properties. During anode life cycle, the carbon content in HPGI was lowed from 3.73 to 3.38%, and different changes in the anodic voltage drop at the stub- collar-anode connection were recorded. The collar temperature increases over the anode life cycle and reaches to 850°C in four weeks after anode changing. Significant changes in the HPGI microstructure were observed after 3 and 30 days from the anode changing. To simulate the actual operating conditions in the steel stub/collar/carbon anode connection, a bench-scale experimental set-up was designed and used for electrical resistance and resistivity respectively. The results showed the current HPGI properties needed to modify or producing new alloys with excellent electrical and mechanical properties. The steel stub and HPGI thermal expansion were measured and studied. Considerable permanent expansion was observed for the HPGI collar after the completion of the heating-cooling cycle.Keywords: high phosphorus gray iron (HPGI), aluminium reduction cells, anodic voltage drop, microstructure, mechanical and electrical properties
Procedia PDF Downloads 4513457 Study of the Responding Time for Low Permeability Reservoirs
Authors: G. Lei, P. C. Dong, X. Q. Cen, S. Y. Mo
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One of the most significant parameters, describing the effect of water flooding in porous media, is flood-response time, and it is an important index in oilfield development. The responding time in low permeability reservoir is usually calculated by the method of stable state successive substitution neglecting the effect of medium deformation. Numerous studies show that the media deformation has an important impact on the development for low permeability reservoirs and can not be neglected. On the base of streamline tube model, we developed a method to interpret responding time with medium deformation factor. The results show that: the media deformation factor, threshold pressure gradient and well spacing have a significant effect on the flood response time. The greater the media deformation factor, threshold pressure gradient or well spacing is, the lower the flood response time is. The responding time of different streamlines varies. As the angle with the main streamline increases, the water flooding response time delays as a "parabola" shape.Keywords: low permeability, flood-response time, threshold pressure gradient, medium deformation
Procedia PDF Downloads 4923456 Physicochemical Characterization of Medium Alkyd Resins Prepared with a Mixture of Linum usitatissimum L. and Plukenetia volubilis L. Oils
Authors: Antonella Hadzich, Santiago Flores
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Alkyds have become essential raw materials in the coating and paint industry, due to their low cost, good application properties and lower environmental impact in comparison with petroleum-based polymers. The properties of these oil-modified materials depend on the type of polyunsaturated vegetable oil used for its manufacturing, since a higher degree of unsaturation provides a better crosslinking of the cured paint. Linum usitatissimum L. (flax) oil is widely used to develop alkyd resins due to its high degree of unsaturation. Although it is intended to find non-traditional sources and increase their commercial value, to authors’ best knowledge a natural source that can replace flaxseed oil has not yet been found. However, Plukenetia volubilis L. oil, of Peruvian origin, contains a similar fatty acid polyunsaturated content to the one reported for Linum usitatissimum L. oil. In this perspective, medium alkyd resins were prepared with a mixture of 50% of Linum usitatissimum L. oil and 50% of Plukenetia volubilis L. oil. Pure Linum usitatissimum L. oil was also used for comparison purposes. Three different resins were obtained by varying the amount of glycerol and pentaerythritol. The synthesized alkyd resins were characterized by FT-IR, and physicochemical properties like acid value, colour, viscosity, density and drying time were evaluated by standard methods. The pencil hardness and chemical resistance behaviour of the cured resins were also studied. Overall, it can be concluded that medium alkyd resins containing Plukenetia volubilis L. oil have an equivalent behaviour compared to those prepared purely with Linum usitatissimum L. oil. Both Plukenetia volubilis L. oil and pentaerythritol have a remarkable influence on certain physicochemical properties of medium alkyd resins.Keywords: alkyd resins, flaxseed oil, pentaerythritol, Plukenetia volubilis L. oil, protective coating
Procedia PDF Downloads 1093455 Optimization of Cu (In, Ga)Se₂ Based Thin Film Solar Cells: Simulation
Authors: Razieh Teimouri
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Electrical modelling of Cu (In,Ga)Se₂ thin film solar cells is carried out with compositionally graded absorber and CdS buffer layer. Simulation results are compared with experimental data. Surface defect layers (SDL) are located in CdS/CIGS interface for improving open circuit voltage simulated structure through the analysis of the interface is investigated with or without this layer. When SDL removed, by optimizing the conduction band offset (CBO) position of the buffer/absorber layers with its recombination mechanisms and also shallow donor density in the CdS, the open circuit voltage increased significantly. As a result of simulation, excellent performance can be obtained when the conduction band of window layer positions higher by 0.2 eV than that of CIGS and shallow donor density in the CdS was found about 1×10¹⁸ (cm⁻³).Keywords: CIGS solar cells, thin film, SCAPS, buffer layer, conduction band offset
Procedia PDF Downloads 2213454 Effects of Medium Composition on the Production of Biomass and a Carbohydrate Isomerase by a Novel Strain of Lactobacillus
Authors: M. Miriam Hernández-Arroyo, Ivonne Caro-Gonzales, Miguel Ángel Plascencia-Espinosa, Sergio R. Trejo-Estrada
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A large biodiversity of Lactobacillus strains has been detected in traditional foods and beverages from Mexico. A selected strain of Lactobacillus sp - PODI-20, used for the obtained from an artisanal fermented beverage was cultivated in different carbon sources in a complex medium, in order to define which carbon sourced induced more effectively the isomerization of arabinose by cell fractions obtained by fermentation. Four different carbon sources were tested in a medium containing peptone and yeast extract and mineral salts. Glucose, galactose, arabinose, and lactose were tested individually at three different concentrations: 3.5, 6, and 10% w/v. The biomass yield ranged from 1.72 to 17.6 g/L. The cell pellet was processed by mechanical homogenization. Both fractions, the cellular debris, and the lysis supernatant were tested for their ability to isomerize arabinose into ribulose. The highest yield of isomer was 12 % of isomerization in the supernatant fractions; whereas up to 9.3% was obtained by the use of cell debris. The isomerization of arabinose has great significance in the production of lactic acid by fermentation of complex carbohydrate hydrolysates.Keywords: isomerase, tagatose, aguamiel, isomerization
Procedia PDF Downloads 3403453 Cell Elevator: A Novel Technique for Cell Sorting and Circulating Tumor Cell Detection and Discrimination
Authors: Kevin Zhao, Norman J. Horing
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A methodology for cells sorting and circulating tumor cell detection and discrimination is presented in this paper. The technique is based on Dielectrophoresis and microfluidic device theory. Specifically, the sorting of the cells is realized by adjusting the relation among the sedimentation forces, the drag force provided by the fluid, and the Dielectrophortic force that is relevant to the bias voltage applied on the device. The relation leads to manipulation of the elevation of the cells of the same kind to a height by controlling the bias voltage. Once the cells have been lifted to a position next to the bottom of the cell collection channel, the buffer fluid flashes them into the cell collection channel. Repeated elevation of the cells leads to a complete sorting of the cells in the sample chamber. A proof-of-principle example is presented which verifies the feasibility of the methodology.Keywords: cell sorter, CTC cell, detection and discrimination, dielectrophoresisords, simulation
Procedia PDF Downloads 4233452 Innovative Small and Medium Sized Firms: Intangible Investment and Financial Constraints - a Literature Review.
Authors: Eliane Abdo
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Small and medium sized firms “SMEs” play essential role in the countries’ economic development mainly in terms of production, employment and equitable distribution of income. For innovative SMEs, the investment in the human capital and in research and development are crucial to survive in a competitive environment. In this paper we perform a literature review to underline the financing difficulties and constraints which innovative SMEs face while investing in intangible assets: not only when defining amount of the investments but also while choosing its financing methods. Literature review revealed that in order to finance their intangible assets, SMEs rely in first on their internal financing: the availability of internal cash flows can then determine their investment’s decision. Moreover SMEs face difficulties to finance their intangibles by financial debts due to the uncertainty of future cash flow and the absence of physical guarantees; they will therefore go for the issuance of new shares as a second choice, since innovative companies have high opportunity of growth that attract new shareholders.Keywords: small and medium sized firms, capital structure, intangible investment, financial constraints
Procedia PDF Downloads 1113451 An Exploration of the Technical and Economic Feasibility of a Stand Alone Solar PV Generated DC Distribution System over AC Distribution System for Use in the Modern as Well as Future Houses of Isolated Areas
Authors: Alpesh Desai, Indrajit Mukhopadhyay
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Standalone Photovoltaic (PV) systems are designed and sized to supply certain AC and/or DC electrical loads. In computers, consumer electronics and many small appliances as well as LED lighting the actual power consumed is DC. The DC system, which requires only voltage control, has many advantages such as feasible connection of the distributed energy sources and reduction of the conversion losses for DC-based loads. Also by using the DC power directly the cost of the size of the Inverter and Solar panel reduced hence the overall cost of the system reduced. This paper explores the technical and economic feasibility of supplying electrical power to homes/houses using DC voltage mains within the house. Theoretical calculated results are presented to demonstrate the advantage of DC system over AC system with PV on sustainable rural/isolated development.Keywords: distribution system, energy efficiency, off-grid, stand-alone PV system, sustainability, techno-socio-economic
Procedia PDF Downloads 2573450 Design and Development of Power Sources for Plasma Actuators to Control Flow Separation
Authors: Himanshu J. Bahirat, Apoorva S. Janawlekar
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Plasma actuators are essential for aerodynamic flow separation control due to their lack of mechanical parts, lightweight, and high response frequency, which have numerous applications in hypersonic or supersonic aircraft. The working of these actuators is based on the formation of a low-temperature plasma between a pair of parallel electrodes by the application of a high-voltage AC signal across the electrodes, after which air molecules from the air surrounding the electrodes are ionized and accelerated through the electric field. The high-frequency operation is required in dielectric discharge barriers to ensure plasma stability. To carry out flow separation control in a hypersonic flow, the optimal design and construction of a power supply to generate dielectric barrier discharges is carried out in this paper. In this paper, it is aspired to construct a simplified circuit topology to emulate the dielectric barrier discharge and study its various frequency responses. The power supply can generate high voltage pulses up to 20kV at the repetitive frequency range of 20-50kHz with an input power of 500W. The power supply has been designed to be short circuit proof and can endure variable plasma load conditions. Its general outline is to charge a capacitor through a half-bridge converter and then later discharge it through a step-up transformer at a high frequency in order to generate high voltage pulses. After simulating the circuit, the PCB design and, eventually, lab tests are carried out to study its effectiveness in controlling flow separation.Keywords: aircraft propulsion, dielectric barrier discharge, flow separation control, power source
Procedia PDF Downloads 1223449 Resonant Tunnelling Diode Output Characteristics Dependence on Structural Parameters: Simulations Based on Non-Equilibrium Green Functions
Authors: Saif Alomari
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The paper aims at giving physical and mathematical descriptions of how the structural parameters of a resonant tunnelling diode (RTD) affect its output characteristics. Specifically, the value of the peak voltage, peak current, peak to valley current ratio (PVCR), and the difference between peak and valley voltages and currents ΔV and ΔI. A simulation-based approach using the Non-Equilibrium Green Function (NEGF) formalism based on the Silvaco ATLAS simulator is employed to conduct a series of designed experiments. These experiments show how the doping concentration in the emitter and collector layers, their thicknesses, and the width of the barriers and the quantum well influence the above-mentioned output characteristics. Each of these parameters was systematically changed while holding others fixed in each set of experiments. Factorial experiments are outside the scope of this work and will be investigated in future. The physics involved in the operation of the device is thoroughly explained and mathematical models based on curve fitting and underlaying physical principles are deduced. The models can be used to design devices with predictable output characteristics. These models were found absent in the literature that the author acanned. Results show that the doping concentration in each region has an effect on the value of the peak voltage. It is found that increasing the carrier concentration in the collector region shifts the peak to lower values, whereas increasing it in the emitter shifts the peak to higher values. In the collector’s case, the shift is either controlled by the built-in potential resulting from the concentration gradient or the conductivity enhancement in the collector. The shift to higher voltages is found to be also related to the location of the Fermi-level. The thicknesses of these layers play a role in the location of the peak as well. It was found that increasing the thickness of each region shifts the peak to higher values until a specific characteristic length, afterwards the peak becomes independent of the thickness. Finally, it is shown that the thickness of the barriers can be optimized for a particular well width to produce the highest PVCR or the highest ΔV and ΔI. The location of the peak voltage is important in optoelectronic applications of RTDs where the operating point of the device is usually the peak voltage point. Furthermore, the PVCR, ΔV, and ΔI are of great importance for building RTD-based oscillators as they affect the frequency response and output power of the oscillator.Keywords: peak to valley ratio, peak voltage shift, resonant tunneling diodes, structural parameters
Procedia PDF Downloads 1383448 In vitro Plant Regeneration of Gonystylus Bancanus (Miq) Kurz. Through Direct Organogenesis
Authors: Grippin Akeng, Suresh Kumar Muniandy, Nor Aini Ab Shukor
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Plant regeneration was achieved from shoot tip and nodal segment of Gonystylus bancanus (Miq) Kurz. cultured in Murashige and Skoog’s medium supplemented with various concentrations of 6-benzylaminopurine (BAP). The most optimum concentration of BAP for shoot initiation is 10.0 mgl⁻¹ with approximately 10% of shoot tip and 15% of nodal segment produced single shoot after 28 and 15 days of culture incubation respectively. Rooting was achieved when shoots were transferred into MS medium supplemented with 5.0 mgl⁻¹ Naphthalene acetic acid (NAA). Synthesizing results developed through this research can be a starting point for the upscalling and optimization process in future.Keywords: gonystylus bancanus, organogenesis, shoot initiation, shoot tip
Procedia PDF Downloads 2423447 Effect of Rotation on Love Wave Propagation in Piezoelectric Medium with Corrugation
Authors: Soniya Chaudhary
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The present study analyses the propagation of Love wave in rotating piezoelectric layer lying over an elastic substrate with corrugated boundaries. The appropriate solutions in the considered medium satisfy the required boundary conditions to obtain the dispersion relation of Love wave for charge free as well as electrically shorted cases. The effects of rotation are shown by graphically on the non-dimensional speed of the Love wave. In addition to classical case, some existing results have been deduced as particular case of the present study. The present study may be useful in rotation sensor and SAW devices.Keywords: corrugation, dispersion relation, love wave, piezoelectric
Procedia PDF Downloads 2203446 Oxidation of Amitriptyline by Bromamine-T in Acidic Buffer Medium: A Kinetic and Mechanistic Approach
Authors: Chandrashekar, R. T. Radhika, B. M. Venkatesha, S. Ananda, Shivalingegowda, T. S. Shashikumar, H. Ramachandra
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The kinetics of the oxidation of amitriptyline (AT) by sodium N-bromotoluene sulphonamide (C6H5SO2NBrNa) has been studied in an acidic buffer medium of pH 1.2 at 303 K. The oxidation reaction of AT was followed spectrophotometrically at maximum wavelength, 410 nm. The reaction rate shows a first order dependence each on concentration of AT and concentration of sodium N-bromotoluene sulphonamide. The reaction also shows an inverse fractional order dependence at low or high concentration of HCl. The dielectric constant of the solvent shows negative effect on the rate of reaction. The addition of halide ions and the reduction product of BAT have no significant effect on the rate. The rate is unchanged with the variation in the ionic strength (NaClO4) of the medium. Addition of reaction mixtures to be aqueous acrylamide solution did not initiate polymerization, indicating the absence of free radical species. The stoichiometry of the reaction was found to be 1:1 and oxidation product of AT is identified. The Michaelis-Menton type of kinetics has been proposed. The CH3C6H5SO2NHBr has been assumed to be the reactive oxidizing species. Thermodynamical parameters were computed by studying the reactions at different temperatures. A mechanism consistent with observed kinetics is presented.Keywords: amitriptyline, bromamine-T, kinetics, oxidation
Procedia PDF Downloads 3333445 Innovativeness of the Furniture Enterprises in Bulgaria
Authors: Radostina Popova
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The paper presents an analysis of the innovation performance of small and medium-sized furniture enterprises in Bulgaria, accounting for over 97% of the companies in the sector. It contains advanced features of innovation in enterprises, specific features of the furniture industry in Bulgaria and analysis of the results of studies on the topic. The results from studies of three successive periods - 2006-2008; 2008-2010; 2010-2012, during which were studied 594 small and medium-sized furniture enterprises. There are commonly used in the EU definitions and indicators (European Commission, OECD, Oslo Manual), which allows for the comparability of results.Keywords: innovation activity, competitiveness of innovation, furniture enterprises in Bulgaria
Procedia PDF Downloads 2653444 Determination of Inactivation and Recovery of Saccharomyces cerevisiae Cells after the Gas-Phase Plasma Treatment
Authors: Z. Herceg, V. Stulic, T. Vukusic, A. Rezek Jambrak
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Gas phase plasma treatment is a new nonthermal technology used for food and water decontamination. In this study, we have investigated influence of the gas phase plasma treatment on yeast cells of S. cerevisiae. Sample was composed of 10 mL of yeast suspension and 190 mL of 0.01 M NaNO₃ with a medium conductivity of 100 µS/cm. Samples were treated in a glass reactor with a point- to-plate electrode configuration (high voltage electrode-titanium wire in the gas phase and grounded electrode in the liquid phase). Air or argon were injected into the headspace of the reactor at the gas flow of 5 L/min. Frequency of 60, 90 and 120 Hz, time of 5 and 10 min and positive polarity were defined parameters. Inactivation was higher with the applied higher frequency, longer treatment time and injected argon. Inactivation was not complete which resulted in complete recovery. Cellular leakage (260 nm and 280 nm) was higher with a longer treatment time and higher frequency. Leakage at 280 nm which defines a leakage of proteins was higher than leakage at 260 nm which defines a leakage of nucleic acids. The authors would like to acknowledge the support by Croatian Science Foundation and research project 'Application of electrical discharge plasma for preservation of liquid foods'.Keywords: Saccharomyces cerevisiae, inactivation, gas-phase plasma treatment, cellular leakage
Procedia PDF Downloads 1943443 A TiO₂-Based Memristor Reliable for Neuromorphic Computing
Authors: X. S. Wu, H. Jia, P. H. Qian, Z. Zhang, H. L. Cai, F. M. Zhang
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A bipolar resistance switching behaviour is detected for a Ti/TiO2-x/Au memristor device, which is fabricated by a masked designed magnetic sputtering. The current dependence of voltage indicates the curve changes slowly and continuously. When voltage pulses are applied to the device, the set and reset processes maintains linearity, which is used to simulate the synapses. We argue that the conduction mechanism of the device is from the oxygen vacancy channel model, and the resistance of the device change slowly due to the reaction between the titanium electrode and the intermediate layer and the existence of a large number of oxygen vacancies in the intermediate layer. Then, Hopfield neural network is constructed to simulate the behaviour of neural network in image processing, and the accuracy rate is more than 98%. This shows that titanium dioxide memristor has a broad application prospect in high performance neural network simulation.Keywords: memristor fabrication, neuromorphic computing, bionic synaptic application, TiO₂-based
Procedia PDF Downloads 743442 Jitter Based Reconstruction of Transmission Line Pulse Using On-Chip Sensor
Authors: Bhuvnesh Narayanan, Bernhard Weiss, Tvrtko Mandic, Adrijan Baric
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This paper discusses a method to reconstruct internal high-frequency signals through subsampling techniques in an IC using an on-chip sensor. Though there are existing methods to internally probe and reconstruct high frequency signals through subsampling techniques; these methods have been applicable mainly for synchronized systems. This paper demonstrates a method for making such non-intrusive on-chip reconstructions possible also in non-synchronized systems. The TLP pulse is used to demonstrate the experimental validation of the concept. The on-chip sensor measures the voltage in an internal node. The jitter in the input pulse causes a varying pulse delay with respect to the on-chip sampling command. By measuring this pulse delay and by correlating it with the measured on-chip voltage, time domain waveforms can be reconstructed, and the influence of the pulse on the internal nodes can be better understood.Keywords: on-chip sensor, jitter, transmission line pulse, subsampling
Procedia PDF Downloads 1403441 Somatic Embryogenesis Derived from Protoplast of Murraya Paniculata L. Jack and Their Regeneration into Plant Flowering in vitro
Authors: Hasan Basri Jumin
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The in vitro flowering of orange jessamine plantlets derived from protoplast was affected by the manipulation of plant growth regulators, sugar and light conditions. MT basal medium containing 5% sucrose and supplemented with 0.001 mg 1-1 indole-acetic-acid was found to be a suitable medium for development of globular somatic embryos derived from protoplasts to form heart-shaped somatic embryos with cotyledon-like structures. The highest percentage (85 %) of flowering was achieved with plantlet on half-strength MT basal medium containing 5% sucrose and 0.001 mg1-1 indole-acetic-acid in light. Exposure to darkness for more than 3 weeks followed by re-exposure to light reduced flowering. Flowering required a 10-day exposure to indole-acetic-acid. Photoperiod with 18 h and 79.4 µmol m-2 s-1 light intensity promoted in vitro flowering in high frequencies. The sucrose treatment affected the flower bud size distribution. Flower buds originating from plantlet derived from protoplasts developed into normal flowers.Keywords: indole-acetc-acid, light-intensity, Murraya-paniculata, photoperiod, plantlet, Zeatin
Procedia PDF Downloads 4143440 The Availability Degree of Transformational Leadership Dimensions among Heads of Scientific Departments in the Education Faculty at King Saud University
Authors: Yahya Al-Gabri
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This study aimed to identify the availability degree of transformational leadership dimensions among heads of scientific departments in the Education Faculty at King Saud University. It also aimed to identify the degree of opinions divergence of the study sample on the availability degree of transformational leadership dimensions among the department heads according to the variable of scientific rank. The researcher used the descriptive approach. The study sample consisted of (34) members of education faculty which chosen randomly. To collect the data, the researcher developed a questionnaire consisting of (47) items distributed on four areas after ensuring validity and reliability. Results showed that the degree of practicing the dimensions of transformational leadership by the heads of scientific departments was medium and the mean was (3.21). The dimension of Individualized consideration came first and had a high degree of availability with a mean of (3.31) and the dimension of idealized influence came secondly and had a medium degree (near of high) of availability with a mean of (3.25), also and the dimension of inspirational motivation came thirdly and had a medium degree of availability with a mean of (3.16), whereas the dimension of intellectual stimulation came finally and had a medium degree of availability with a mean of (3.13). The study also showed that there are no statistically significant differences at the level of significance (0.05) in the availability degree of transformational leadership dimensions among the heads of scientific departments at the Faculty of Education according to the scientific rank variable. Finally, the researcher made a number of recommendations and suggestions.Keywords: transformational leadership, heads of scientific departments, individualized consideration, idealized influence, inspirational motivation, intellectual stimulation
Procedia PDF Downloads 1493439 A Review on Electrical Behavior of Different Substrates, Electrodes and Membranes in Microbial Fuel Cell
Authors: Bharat Mishra, Sanjay Kumar Awasthi, Raj Kumar Rajak
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The devices, which convert the energy in the form of electricity from organic matters, are called microbial fuel cell (MFC). Recently, MFCs have been given a lot of attention due to their mild operating conditions, and various types of biodegradable substrates have been used in the form of fuel. Traditional MFCs were included in anode and cathode chambers, but there are single chamber MFCs. Microorganisms actively catabolize substrate, and bioelectricities are produced. In the field of power generation from non-conventional sources, apart from the benefits of this technique, it is still facing practical constraints such as low potential and power. In this study, most suitable, natural, low cost MFCs components are electrodes (anode and cathode), organic substrates, membranes and its design is selected on the basis of maximum potential (voltage) as an electrical parameter, which indicates a vital role of affecting factor in MFC for sustainable power production.Keywords: substrates, electrodes, membranes, MFCs design, voltage
Procedia PDF Downloads 2973438 Food Traceability for Small and Medium Enterprises Using Blockchain Technology
Authors: Amit Kohli, Pooja Lekhi, Gihan Adel Amin Hafez
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Blockchain is a distributor ledger technology trend that extended to different fields and proved a remarkable success. Blockchain technology is a vital proliferation technique that recuperates the food supply chain traceability process. While tracing is the core of the food supply chain; still, a complex system mitigates the exceptional risk of food contamination, foodborne, food waste, and food fraud. In addition, the upsurge of food supply chain data variance and variety in the traceability system requires complete transparency, a secure, steadfast, sustainable, and efficient approach to face the food supply chain challenges. On the other hand, blockchain technical aspects merged with a detailed implementation plan, the advantages and challenges in food traceability have not been much elucidated for small and medium enterprises (SMEs.) This paper demonstrated the advantages and challenges of applying blockchain in SMEs combined with the success stories of firms implementing blockchain to cover the gap. Moreover, blockchain architecture in SMEs and how technology, organization, and environment frameworks can guarantee the success of blockchain implementation have been revealed.Keywords: blockchain technology, small and medium enterprises, food traceability, blockchain architecture
Procedia PDF Downloads 1803437 From Theory to Practice: An Iterative Design Process in Implementing English Medium Instruction in Higher Education
Authors: Linda Weinberg, Miriam Symon
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While few institutions of higher education in Israel offer international programs taught entirely in English, many Israeli students today can study at least one content course taught in English during their degree program. In particular, with the growth of international partnerships and opportunities for student mobility, English medium instruction is a growing phenomenon. There are however no official guidelines in Israel for how to develop and implement content courses in English and no training to help lecturers prepare for teaching their materials in a foreign language. Furthermore, the implications for the students and the nature of the courses themselves have not been sufficiently considered. In addition, the institution must have lecturers who are able to teach these courses effectively in English. An international project funded by the European Union addresses these issues and a set of guidelines which provide guidance for lecturers in adapting their courses for delivery in English have been developed. A train-the-trainer approach is adopted in order to cascade knowledge and experience in English medium instruction from experts to language teachers and on to content teachers thus maximizing the scope of professional development. To accompany training, a model English medium course has been created which serves the dual purpose of highlighting alternatives to the frontal lecture while integrating language learning objectives with content goals. This course can also be used as a standalone content course. The development of the guidelines and of the course utilized backwards, forwards and central design in an iterative process. The goals for combined language and content outcomes were identified first after which a suitable framework for achieving these goals was constructed. The assessment procedures evolved through collaboration between content and language specialists and subsequently were put into action during a piloting phase. Feedback from the piloting teachers and from the students highlight the need for clear channels of communication to encourage frank and honest discussion of expectations versus reality. While much of what goes on in the English medium classroom requires no better teaching skills than are required in any classroom, the understanding of students' abilities in achieving reasonable learning outcomes in a foreign language must be rationalized and accommodated within the course design. Concomitantly, preparatory language classes for students must be able to adapt to prepare students for specific language and cognitive skills and activities that courses conducted in English require. This paper presents findings from the implementation of a purpose-designed English medium instruction course arrived at through an iterative backwards, forwards and central design process utilizing feedback from students and lecturers alike leading to suggested guidelines for English medium instruction in higher education.Keywords: English medium instruction, higher education, iterative design process, train-the-trainer
Procedia PDF Downloads 2953436 Acid-Responsive Polymer Conjugates as a New Generation of Corrosion Protecting Materials
Authors: Naruphorn Dararatana, Farzad Seidi, Daniel Crespy
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Protection of metals is a critical issue in industry. The annual cost of corrosion in the world is estimated to be about 2.5 trillion dollars and continuously increases. Therefore, there is a need for developing novel protection approaches to improve corrosion protection. We designed and synthesized smart polymer/corrosion inhibitor conjugates as new generations of corrosion protecting materials. Firstly, a polymerizable acrylate derivative of 8-hydroxyquinoline (8HQ), an effective corrosion inhibitor, containing acid-labile β-thiopropionate linkage was prepared in three steps. Then, it was copolymerized with ethyl acrylate in the presence of 1,1′-azobis(cyclohexanecarbonitrile) (ABCN) by radical polymerization. Nanoparticles with an average diameter of 140 nm were prepared from the polymer conjugate by the miniemulsion-solvent evaporation process. The release behavior of 8HQ from the the nanoparticles was studied in acidic (pH 3.5) and neutral media (pH 7.0). The release profile showed a faster release of 8HQ in acidic medium in comparison with neutral medium. Indeed 100% of 8HQ was released after 14 days in acidic medium whereas only around 15% of 8HQ was released during the same period at neutral pH. Therefore, the polymer conjugate nanoparticles are suitable materials as additives or to form coatings on metal substrates for corrosion protection.Keywords: Corrosion inhibitor, 8-Hydroxyquinoline, Polymer conjugated, β-Thiopropionate
Procedia PDF Downloads 1863435 Moderate Electric Field Influence on Carotenoids Extraction Time from Heterochlorella luteoviridis
Authors: Débora P. Jaeschke, Eduardo A. Merlo, Rosane Rech, Giovana D. Mercali, Ligia D. F. Marczak
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Carotenoids are high value added pigments that can be alternatively extracted from some microalgae species. However, the application of carotenoids synthetized by microalgae is still limited due to the utilization of organic toxic solvents. In this context, studies involving alternative extraction methods have been conducted with more sustainable solvents to replace and reduce the solvent volume and the extraction time. The aim of the present work was to evaluate the extraction time of carotenoids from the microalgae Heterochlorella luteoviridis using moderate electric field (MEF) as a pre-treatment to the extraction. The extraction methodology consisted of a pre-treatment in the presence of MEF (180 V) and ethanol (25 %, v/v) for 10 min, followed by a diffusive step performed for 50 min using a higher ethanol concentration (75 %, v/v). The extraction experiments were conducted at 30 °C and, to keep the temperature at this value, it was used an extraction cell with a water jacket that was connected to a water bath. Also, to enable the evaluation of MEF effect on the extraction, control experiments were performed using the same cell and conditions without voltage application. During the extraction experiments, samples were withdrawn at 1, 5 and 10 min of the pre-treatment and at 1, 5, 30, 40 and 50 min of the diffusive step. Samples were, then, centrifuged and carotenoids analyses were performed in the supernatant. Furthermore, an exhaustive extraction with ethyl acetate and methanol was performed, and the carotenoids content found for this analyses was considered as the total carotenoids content of the microalgae. The results showed that the application of MEF as a pre-treatment to the extraction influenced the extraction yield and the extraction time during the diffusive step; after the MEF pre-treatment and 50 min of the diffusive step, it was possible to extract up to 60 % of the total carotenoids content. Also, results found for carotenoids concentration of the extracts withdrawn at 5 and 30 min of the diffusive step did not presented statistical difference, meaning that carotenoids diffusion occurs mainly in the very beginning of the extraction. On the other hand, the results for control experiments showed that carotenoids diffusion occurs mostly during 30 min of the diffusive step, which evidenced MEF effect on the extraction time. Moreover, carotenoids concentration on samples withdrawn during the pre-treatment (1, 5 and 10 min) were below the quantification limit of the analyses, indicating that the extraction occurred in the diffusive step, when ethanol (75 %, v/v) was added to the medium. It is possible that MEF promoted cell membrane permeabilization and, when ethanol (75 %) was added, carotenoids interacted with the solvent and the diffusion occurred easily. Based on the results, it is possible to infer that MEF promoted the decrease of carotenoids extraction time due to the increasing of the permeability of the cell membrane which facilitates the diffusion from the cell to the medium.Keywords: moderate electric field (MEF), pigments, microalgae, ethanol
Procedia PDF Downloads 4563434 Using the Nonlocal Theory of Free Vibrations Nanobeam
Authors: Ali Oveysi Sarabi
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The dimensions of nanostructures are in the range of inter-atomic spacing of the structures which makes them impossible to be modeled as a continuum. Nanoscale size-effects on vibration analysis of nanobeams embedded in an elastic medium is investigated using different types of beam theory. To this end, Eringen’s nonlocal elasticity is incorporated to various beam theories namely as Euler-Bernoulli beam theory (EBT), Timoshenko beam theory (TBT), Reddy beam theory (RBT), and Levinson beam theory (LBT). The surrounding elastic medium is simulated with both Winkler and Pasternak foundation models and the difference between them is studies. Explicit formulas are presented to obtain the natural frequencies of nanobeam corresponding to each nonlocal beam theory. Selected numerical results are given for different values of the non-local parameter, Winkler modulus parameter, Pasternak modulus parameter and aspect ratio of the beam that imply the effects of them, separately. It is observed that the values of natural frequency are strongly dependent on the stiffness of elastic medium and the value of the non-local parameter and these dependencies varies with the value of aspect ratio and mode number.Keywords: nanobeams, free vibration, nonlocal elasticity, winkler foundation model, Pasternak foundation model, beam theories
Procedia PDF Downloads 5293433 Optimization and Design of Current-Mode Multiplier Circuits with Applications in Analog Signal Processing for Gas Industrial Package Systems
Authors: Mohamad Baqer Heidari, Hefzollah.Mohammadian
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This brief presents two original implementations of improved accuracy current-mode multiplier/divider circuits. Besides the advantage of their simplicity, these original multiplier/divider structures present the advantage of very small linearity errors that can be obtained as a result of the proposed design techniques (0.75% and 0.9%, respectively, for an extended range of the input currents). The original multiplier/divider circuits permit a facile reconfiguration, the presented structures representing the functional basis for implementing complex function synthesizer circuits. The proposed computational structures are designed for implementing in 0.18-µm CMOS technology, with a low-voltage operation (a supply voltage of 1.2 V). The circuits’ power consumptions are 60 and 75 µW, respectively, while their frequency bandwidths are 79.6 and 59.7 MHz, respectively.Keywords: analog signal processing, current-mode operation, functional core, multiplier, reconfigurable circuits, industrial package systems
Procedia PDF Downloads 3713432 A Multilevel-Synthesis Approach with Reduced Number of Switches for 99-Level Inverter
Authors: P. Satish Kumar, V. Ramu, K. Ramakrishna
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In this paper, an efficient multilevel wave form synthesis technique is proposed and applied to a 99-level inverter. The basic principle of the proposed scheme is that the continuous output voltage levels can be synthesized by the addition or subtraction of the instantaneous voltages generated from different voltage levels. This synthesis technique can be realized by an array of switching devices composing full-bridge inverter modules and proper mixing of each bi-directional switch modules. The most different aspect, compared to the conventional approach, in the synthesis of the multilevel output waveform is the utilization of a combination of bidirectional switches and full bridge inverter modules with reduced number of components. A 99-level inverter consists of three full-bridge modules and six bi-directional switch modules. The validity of the proposed scheme is verified by the simulation.Keywords: cascaded connection, multilevel inverter, synthesis, total harmonic distortion
Procedia PDF Downloads 5213431 Film Diplomacy: An Approach to International Relations
Authors: Lawrence Akande
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Despite the efforts of African countries' governments and the foreign countries' governments, there are cautions between the people of Africa and the people of other countries. The cautions are based on the ideology of misconception, which comes from the narratives about Africa and African people and narratives about other people also. The film is a medium of educating people about people from foreign countries they have never been to. Negative or misconceived narratives about a people will affect the relations between the peoples, despite the efforts of the government. Using pop-culture medium of film as a diplomatic tool will promote mutual understanding and respect.Keywords: film diplomacy, international relations, narratives, Nollywood, partnership
Procedia PDF Downloads 1913430 Power Quality Issues: Power Supply Interruptions as Key Constraint to Development in Ekiti State, Nigeria
Authors: Oluwatosin S. Adeoye
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The power quality issues in the world today are critical to the development of different nations. Prosperity of each nation depends on availability of constant power supply. Constant power supply is a major challenge in Africa particularly in Nigeria where the generated power is than thirty percent of the required power. The metrics of power quality are voltage dip, flickers, spikes, harmonics and interruptions. The level of interruptions in Ekiti State was examined through the investigation of the causes of power interruptions in the State. The method used was the collection of data from the Distribution Company, assessment through simple programming as a command for plotting the graphs through the use of MATLAB 2015 depicting the behavioural pattern of the interruption for a period of six months in 2016. The result shows that the interrelationship between the interruptions and development. Recommendations were suggested with the objective of solving the problems being set up by interruptions in the State and these include installation of reactors, automatic voltage regulators and effective tap changing system on the lines, busses and transformer substation respectively.Keywords: development, frequency, interruption, power, quality
Procedia PDF Downloads 156