Search results for: heat source / sink

Authors: Alain Kusmoko, Druce Dunne, Huijun Li

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Stellite 6 was deposited by laser cladding on a chromium bearing substrate (P91) with energy inputs of 1 kW (P91-1) and 1.8 kW (P91-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was assessed using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the P91 steel substrate with the lower heat input (P91-1). Further, the Stellite coating for P91-1 was significantly harder than that obtained for P91-1.8. The wear test results indicated that the weight loss for P91-1 was much lower than for P91-1.8. It is concluded that the lower hardness of the coating for P91-1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.

Keywords: friction and wear, laser cladding, P91 steel, Stellite 6 coating

Procedia PDF Downloads 424

Authors: Hameed B. Mahood, Ali Sh. Baqir

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Vaporization of a single n-pentane drop in a direct contact with another flowing immiscible liquid (warm water) has been experimentally investigated. The experiments were carried out utilising a cylindrical Perspex tube of diameter 10 cm and height and 150 cm. Saturated liquid n-pentane and warm water at 45oC were used as the dispersed and continuous phases, respectively. Photron FASTCAM SA 1.1high speed camera (75,000f/s) with software V. 321 was implemented during the experiments. Five different continuous phase flow rates (warm water) (10, 20, 30, 40, and 46 L⁄h) were used in the study. The results indicated that the increase of the continuous phase (warm water) flow rate results in increasing of the drop/bubble diameter.

Keywords: drop evaporation, direct contact heat transfer, drop/bubble growth, experimental technique

Procedia PDF Downloads 334

Authors: G. Sivakumar, T. Pratyusha, D. Gupta, W. Shen

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To get ohmic contact between the cathode and organic semiconductor, transport layers are introduced between the active layer and the electrodes. Generally zinc oxide or titanium dioxide are used as electron transport layer. When electron transport layer is doped with lithium, the resultant film exhibited superior electronic properties, which enables faster electron transport. Doping is accomplished by heat treatment of films with Lithium salts. Li-doped films. We fabricated organic solar cell using PTB7(poly(3-hexylthiopene-2,5- diyl):PCBM(phenyl-C61-butyric acid methyl ester) and found that the solar cells prepared using Li doped films had better performance in terms of efficiency when compared to the undoped transport layers.

Keywords: electron transport layer, higher efficiency, lithium doping, ohmic contact

Procedia PDF Downloads 489

Authors: Mohammad Alhajeri

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This paper reports a computational fluid dynamics (CFD) investigation of cylindrical filter. Silicon carbide cylindrical filter elements have proven to be an effective mean of removing particulates to levels exceeding the new source performance standard. The CFD code is used here to understand the deposition process and the factors that affect the particles distribution over the filter element surface. Different approach cross flow velocity to filter face velocity ratios and different face velocities (ranging from 2 to 5 cm/s) are used in this study. Particles in the diameter range 1 to 100 microns are tracked through the domain. The radius of convergence (or the critical trajectory) is compared and plotted as a function of many parameters.

Keywords: filtration, CFD, CCF, hot gas filtration

Procedia PDF Downloads 449

Authors: Ali M. Elgerbi, Obied A. Alwan, Al-Taher O. Alzwei, Abdurrahim A. Elouzi

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The binding of AFM1 to bacteria in phosphate buffer solution depended on many factors such as: availability of energy, incubation period, species and strain of bacteria. Increase in concentration of sugar showed higher removal of AFM1 and faster than in phosphate buffer alone. With 1.0% glucose lactic acid bacteria and bifidobacteria showed toxin removal ranging from 7.7 to 39.7% whereas with 10.0% glucose the percentage removal was 21.8 to 45.4% at 96 hours of incubation.

Keywords: aflatoxin M1, lactic acid bacteria, bifidobacteria , binding, phosphate buffer

Procedia PDF Downloads 491

Authors: A. J. Netshipale, M. L. Mashiloane, S. J. Oosting, I. J. M. De Boer, E. N. Raidimi

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Three tier land reform programme (land restitution, land redistribution and land tenure reform) had been implemented for the past two decades in South Africa with an aim of redressing the unjust land ownership patterns of the past. Land restitution and redistribution seeked to make land available for beneficiaries’ ownership based on policy guidelines. Attention given to the two sub-programmes was mostly land reform focused with the quantity of land that exchanged ownership being used as a measure of success with disregard for how the land is used by the beneficiaries for their livelihoods. In few cases that the land use assessment was done for the two sub-programmes it was assessed on a case basis or few selected cases. The current study intended to shed light on a broader scope. This study investigated the extent to which land reform farms were used and contribution made by farms to the livelihoods of active beneficiaries. Seventy six farms that represented restitution (16 farms) and redistribution (60) programmes were selected for land use investigation. Land use data were collected from farm representatives by means of semi-structured questionnaire. A stratified sample of 87 households (38 for restitution and 49 for redistribution) were selected for livelihood investigations. Data on income generating activities and passive income sources were collected from household heads using semi-structured questionnaire. Additional data were collected through focus group discussions and from stakeholders through key-informants interviews. Livestock production used more land per farm on average (45%) in relation to the amount of average total land used per farm of 77% under land redistribution programme. Land restitution transformed crop farms into mixed farming and unused farms to be under use while land redistribution converted conservation land into agricultural land and also unused farms to be used. Livestock production contributed on average 25% to the livelihoods of 48% of the households whereas crop production contributed 31% on average to the livelihoods of 67% of the households. Government grants had the highest contribution of 54% on average and contributed to most households (72%). Agriculture was the sole source of livelihoods to only three per cent of the households. Most households (40%) had a mix of three livelihoods sources as their livelihood strategy. It could be concluded that the use of reformed land would be mainly influenced by the agro-ecological conditions of the area and agriculture could not be the main source of livelihoods for households that benefited from land reform. Land reform policies which accommodate diverse livelihoods activities could contribute to sustainable livelihoods.

Keywords: active beneficiaries, households, land reform, land use, livelihoods

Procedia PDF Downloads 181

Authors: Alfred L. Guiffrida

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A review of the literature on supply chain delivery models which use delivery windows to measure delivery performance is presented. The review herein serves to meet the following objectives: (i) provide a synthesis of previously published literature on supply chain delivery performance models, (ii) provide in one paper a consolidation of research that can serve as a single source to keep researchers up to date with the research developments in supply chain delivery models, and (iii) identify gaps in the modeling of supply chain delivery performance which could stimulate new research agendas.

Keywords: delivery performance, delivery window, supply chain delivery models, supply chain performance

Procedia PDF Downloads 405

Authors: Munir Tasdemir

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Polymer/clay composites have received great attention in the past three decades owing to their light weight coupled with significantly better mechanical and barrier properties than the corresponding neat polymer resins. An investigation was carried out on the effects of red mud powder size and ratio on the mechanical and thermal properties of polypropylene /red mud polymer composites. Red mud, in four different concentrations (0, 10, 20 and 30 wt %) and three different powder size (180, 63 and 38 micron) were added to PP to produce composites. The mechanical properties, including the elasticity modulus, tensile & yield strength, % elongation, hardness, Izod impact strength and the thermal properties including the melt flow index, heat deflection temperature and vicat softening point of the composites were investigated. The structures of the composites were investigated by scanning electron microscopy and compared to mechanical and thermal properties as a function of red mud powder content and size.

Keywords: polypropylene, powder, red mud, mechanical properties

Procedia PDF Downloads 317

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

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

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

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Authors: A. S. Obaid, K. H. T. Hassan, A. M. Asij, B. M. Salih, M. Bououdina

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Cadmium Oxide (CdO) thin films have been prepared by vacuum evaporation method on Si (111) substrate at room temperature using CdCl2 as a source of Cd. Detailed structural properties of the films are presented using XRD and SEM. The films was pure polycrystalline CdO phase with high crystallinity. The lattice constant average crystallite size of the nanocrystalline CdO thin films were calculated. SEM image confirms the formation nanostructure. Energy dispersive X-ray analysis spectra of CdO thin films shows the presence of Cd and O peaks only, no additional peaks attributed to impurities or contamination are observed.

Keywords: nanostructured CdO, solid-vapor deposition, quantum size effect, cadmium oxide

Procedia PDF Downloads 651

Authors: Chang Su Woo, Hyun Sung Park

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Useful lifetime evaluation of chevron rubber spring was very important in design procedure to assure the safety and reliability. It is, therefore, necessary to establish a suitable criterion for the replacement period of chevron rubber spring. In this study, we performed characteristic analysis and useful lifetime prediction of chevron rubber spring. Rubber material coefficient was obtained by curve fittings of uni-axial tension, equi bi-axial tension and pure shear test. Computer simulation was executed to predict and evaluate the load capacity and stiffness for chevron rubber spring. In order to useful lifetime prediction of rubber material, we carried out the compression set with heat aging test in an oven at the temperature ranging from 50°C to 100°C during a period 180 days. By using the Arrhenius plot, several useful lifetime prediction equations for rubber material was proposed.

Keywords: chevron rubber spring, material coefficient, finite element analysis, useful lifetime prediction

Procedia PDF Downloads 553

Authors: K. Shahril, M. Ridzuan, M. Sabri

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The disc rotor is solid, ventilated or drilled. The ventilated type disc rotor consists of a wider disc with cooling fins cast through the middle to ensure good cooling. The disc brakes use pads that are pressed axially against a rotor or disc. Solid and ventilated disc design are same which it free with any form, unless inside the ventilated disc has several ventilation holes. Different with drilled disc has some construction on the surface which is has six lines of drill hole penetrate the disc and a little bit deep twelve curves. From the thermal analysis that was conducted by using ANSYS Software, temperature distribution and heat transfer rate on the disc were obtained on each design. Temperature occurred on the drilled disc was lowest than ventilated and solid disc, it is 66% better than ventilated while ventilated is 21% good than solid disc.

Keywords: disc brakes, drilled disc, thermal analysis, ANSYS software

Procedia PDF Downloads 372

Authors: Beste Kaysı, Yasemin Topaloğlu

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Usability is one of the most important quality attributes for web-based information systems. Specifically, for e-commerce applications, usability becomes more prominent. In this study, we aimed to explore the features that experienced users seek in e-commerce applications. We used eye tracking method in evaluations. Eye movement data are obtained from the eye-tracking method and analyzed based on task completion time, number of fixations, as well as heat map and gaze plot measures. The results of the analysis show that the eye movements of participants' are too static in certain areas and their areas of interest are scattered in many different places. It has been determined that this causes users to fail to complete their transactions. According to the findings, we outlined the issues to improve the usability of e-commerce websites. Then we propose solutions to identify the issues. In this way, it is expected that e-commerce sites will be developed which will make experienced users more satisfied.

Keywords: e-commerce websites, eye tracking method, usability, website evaluations

Procedia PDF Downloads 168

Authors: Renée M. Ripken, Johannes G. E. Gardeniers, Séverine Le Gac

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Controlling the multiphase behavior of aqueous biomass mixtures is essential when working in the biomass conversion industry. Here, the vapor/liquid equilibria (VLE) of ethylene glycol, glycerol, and xylitol were studied for temperatures between 25 and 200 °C and pressures of 1 to 10 bar. These experiments were performed in a microfluidic platform, which exhibits excellent heat transfer properties so that equilibrium is reached fast. Firstly, the saturated vapor pressure as a function of the temperature and the substrate mole fraction of the substrate was calculated using AspenPlus with a Redlich-Kwong-Soave Boston-Mathias (RKS-BM) model. Secondly, we developed a high-pressure and high-temperature microfluidic set-up for experimental validation. Furthermore, we have studied the multiphase flow pattern that occurs after the saturation temperature was achieved. A glass-silicon microfluidic device containing a 0.4 or 0.2 m long meandering channel with a depth of 250 μm and a width of 250 or 500 μm was fabricated using standard microfabrication techniques. This device was placed in a dedicated chip-holder, which includes a ceramic heater on the silicon side. The temperature was controlled and monitored by three K-type thermocouples: two were located between the heater and the silicon substrate, one to set the temperature and one to measure it, and the third one was placed in a 300 μm wide and 450 μm deep groove on the glass side to determine the heat loss over the silicon. An adjustable back pressure regulator and a pressure meter were added to control and evaluate the pressure during the experiment. Aqueous biomass solutions (10 wt%) were pumped at a flow rate of 10 μL/min using a syringe pump, and the temperature was slowly increased until the theoretical saturation temperature for the pre-set pressure was reached. First and surprisingly, a significant difference was observed between our theoretical saturation temperature and the experimental results. The experimental values were 10’s of degrees higher than the calculated ones and, in some cases, saturation could not be achieved. This discrepancy can be explained in different ways. Firstly, the pressure in the microchannel is locally higher due to both the thermal expansion of the liquid and the Laplace pressure that has to be overcome before a gas bubble can be formed. Secondly, superheating effects are likely to be present. Next, once saturation was reached, the flow pattern of the gas/liquid multiphase system was recorded. In our device, the point of nucleation can be controlled by taking advantage of the pressure drop across the channel and the accurate control of the temperature. Specifically, a higher temperature resulted in nucleation further upstream in the channel. As the void fraction increases downstream, the flow regime changes along the channel from bubbly flow to Taylor flow and later to annular flow. All three flow regimes were observed simultaneously. The findings of this study are key for the development and optimization of a microreactor for hydrogen production from biomass.

Keywords: biomass conversion, high pressure and high temperature microfluidics, multiphase, phase diagrams, superheating

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Authors: Karima Oldyerou, B. Meddah, A. Tirtouil

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Laurusnobilis is an aromatic plant, common in Algeria and widely used by local people as a source of spice and for medicinal purposes. The essential oil of this plant is the subject of this work in a physicochemical and microbiological study. The extraction of the essential oil was carried by steam distillation and the highest yield (1.5%) was determined in May. The organoleptic and physico-chemical characters are consistent with those obtained in the literature with some differences that can be attributed to certain factors. Evaluation of antibacterial activity showed a sensitivity of Salmonella spp. with an MIC of 2,5 mg.ml-1, and other bacteria of the intestinal flora of Wistar rats: E. coli and Lactobacillus sp. have a high potential for resistance with MICs respectively equal to 10 and 20 mg.ml-1.

Keywords: laurus nobilis, essential oil, physicochemical character, MIC, intestinal flora, antibacterial activity

Procedia PDF Downloads 312

Authors: Leal Leonardo, Pires Carlos Augusto de Moraes, Casiraghi Magela

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In this work were realized the modeling and simulation of the catalytic reformer process, of ample form, considering all the equipment that influence the operation performance. Considered it a semi-regenerative reformer, with four reactors in series intercalated with four furnaces, two heat exchanges, one product separator and one recycle compressor. A simplified reactional system was considered, involving only ten chemical compounds related through five reactions. The considered process was the applied to aromatics production (benzene, toluene, and xylene). The models developed to diverse equipment were interconnecting in a simulator that consists of a computer program elaborate in FORTRAN 77. The simulation of the global model representative of reformer unity achieved results that are compatibles with the literature ones. It was then possible to study the effects of operational variables in the products concentration and in the performance of the unity equipment.

Keywords: catalytic reforming, modeling, simulation, petrochemical engineering

Procedia PDF Downloads 496

Authors: Brahim Mahfoud, Rachid Bessaïh

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In this paper, a numerical study of steady and oscillatory flows with heat transfer submitted to an axial magnetic field is studied. The governing Navier-Stokes, energy, and potential equations along with appropriate boundary conditions are solved by using the finite-volume method. The flow and temperature fields are presented by stream function and isotherms, respectively. The flow between counter-rotating end disks is very unstable and reveals a great richness of structures. The results are presented for various values of the Hartmann number, Ha=5, 10, 20, and 30, and Richardson numbers , Ri=0, 0.5, 1, 2, and 4, in order to see their effects on the value of the critical Reynolds number, Recr. Stability diagrams are established according to the numerical results of this investigation. These diagrams put in evidence the dependence of Recr with the increase of Ha for various values of Ri.

Keywords: swirling, counter-rotating end disks, magnetic field, oscillatory, cylinder

Procedia PDF Downloads 313

Authors: H. Fazlinejad, A. Halvaee

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In this study, characteristics of ATIG welds using ZnO flux on aluminum was investigated and compared with TIG welds. Autogenously AC-ATIG bead on plate welding was applied on Al1050 plate with a coating of ZnO as the flux. Different levels of welding current and flux layer thickness was considered to study the effect of heat input and flux quantity on ATIG welds and was compared with those of TIG welds. Geometrical investigation of the weld cross sections revealed that penetration depth of the ATIG welds with ZnO flux, was increased up to 2 times in some samples compared to the TIG welds. Optical metallographic and Scanning Electron Microscopy (SEM) observations revealed similar microstructures in TIG and ATIG welds. Composition of the ATIG welds slag was also analyzed using X-ray diffraction. In both TIG and ATIG samples, the lowest values of microhardness were observed in the HAZ.

Keywords: ATIG, active flux, weld penetration, Al 1050, ZnO

Procedia PDF Downloads 150

Authors: Antoni Wibowo, Harry Pujianto, Dewi Retno Sari Saputro

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The stock market can provide huge profits in a relatively short time in financial sector; however, it also has a high risk for investors and traders if they are not careful to look the factors that affect the stock market. Therefore, they should give attention to the dynamic fluctuations and movements of the stock market to optimize profits from their investment. In this paper, we present a nonlinear autoregressive exogenous model (NARX) to predict the movements of stock market; especially, the movements of the closing price index. As case study, we consider to predict the movement of the closing price in Indonesia composite index (IHSG) and choose the best structures of NARX for IHSG’s prediction.

Keywords: NARX (Nonlinear Autoregressive Exogenous Model), prediction, stock market, time series

Procedia PDF Downloads 229

Authors: Asad Abbas, Muhammad Fezan Afzal, Muhammad Latif Anjum, Muhammad Azmat

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The Internet of Things (IoT) is used to link up real objects that use the internet to interact. IoT applications allow handling and operating the equipment in accordance with environmental needs, such as transportation and healthcare. IoT devices are linked together via a number of agents that act as a middleman for communications. The operation of a heat sensor differs indoors and outside because agent applications work with environmental variables. In this article, we suggest using Software Product Line (SPL) to model IoT agents and applications' features on an XML-based basis. The contextual diversity within the same domain of application can be handled, and the reusability of features is increased by XML-based feature modelling. For the purpose of managing contextual variability, we have embraced XML for modelling IoT applications, agents, and internet-connected devices.

Keywords: IoT agents, IoT applications, software product line, feature model, XML

Procedia PDF Downloads 77

Authors: Elif Tugce Aksun Tumerkan, Umran Cansu, Gokhan Boran, Fatih Ozogul

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Gelatin is a mixture of peptides obtained from collagen by partial thermal hydrolysis. It is an important and useful biopolymer that is used in the food, pharmacy, and photography products. Generally, gelatins are sourced from pig skin and bones, beef bone and hide, but within the last decade, using alternative gelatin resources has attracted some interest. In this study, functional properties of gelatin extracted from seafood and poultry by-products were evaluated. For this purpose, skins of skipjack tuna (Katsuwonus pelamis) and frog (Rana esculata) were used as seafood by-products and chicken skin as poultry by-product as raw material for gelatin extraction. Following the extraction of gelatin, all samples were lyophilized and stored in plastic bags at room temperature. For comparing gelatins obtained; chemical composition, common quality parameters including bloom value, gel strength, and viscosity in addition to some others like melting and gelling temperatures, hydroxyproline content, and colorimetric parameters were determined. The results showed that the highest protein content obtained in frog gelatin with 90.1% and the highest hydroxyproline content was in chicken gelatin with 7.6% value. Frog gelatin showed a significantly higher (P < 0.05) melting point (42.7°C) compared to that of fish (29.7°C) and chicken (29.7°C) gelatins. The bloom value of gelatin from frog skin was found higher (363 g) than chicken and fish gelatins (352 and 336 g, respectively) (P < 0.05). While fish gelatin had higher lightness (L*) value (92.64) compared to chicken and frog gelatins, redness/greenness (a*) value was significantly higher in frog skin gelatin. Based on the results obtained, it can be concluded that skins of different animals with high commercial value may be utilized as alternative sources to produce gelatin with high yield and desirable functional properties. Functional and quality analysis of gelatin from frog, chicken, and tuna skin showed by-product of poultry and seafood can be used as an alternative gelatine source to mammalian gelatine. The functional properties, including bloom strength, melting points, and viscosity of gelatin from frog skin were more admirable than that of the chicken and tuna skin. Among gelatin groups, significant characteristic differences such as gel strength and physicochemical properties were observed based on not only raw material but also the extraction method.

Keywords: chicken skin, fish skin, food industry, frog skin, gel strength

Procedia PDF Downloads 143

Authors: Chabungbam Niranjit Khuman, Makarand Madhao Ghangrekar, Arunabha Mitra

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The cost of aeration is one of the limiting factors in the upscaling of microbial fuel cells (MFC) for field-scale applications. Wetland macrophytes have the ability to release oxygen into the water to maintain aerobic conditions in their root zone. In this experiment, the efficacy of rhizospheric oxygen release of wetland macrophytes as a source of oxygen in the cathodic chamber of MFC was conducted. The experiment was conducted in an MFC consisting of a three-liter anodic chamber made of ceramic cylinder and a 27 L cathodic chamber. Untreated carbon felts were used as electrodes (i.e., anode and cathode) and connected to an external load of 100 Ω using stainless steel wire. Wetland macrophytes (Canna indica) were grown in the cathodic chamber of the MFC in a hydroponic fashion using a styrofoam sheet (termed as macrophytes assisted-microbial fuel cell, M-MFC). The catholyte (i.e., water) in the M-MFC had negligible contact with atmospheric air due to the styrofoam sheet used for maintaining the hydroponic condition. There was no mixing of the catholyte in the M-MFC. Sucrose based synthetic wastewater having chemical oxygen demand (COD) of 3000 mg/L was fed into the anodic chamber of the MFC in fed-batch mode with a liquid retention time of four days. The C. indica thrived well throughout the duration of the experiment without much care. The average dissolved oxygen (DO) concentration and pH value in the M-MFC were 3.25 mg/L and 7.07, respectively, in the catholyte. Since the catholyte was not in contact with air, the DO in the catholyte might be considered as solely liberated from the rhizospheric oxygen release of C. indica. The maximum COD removal efficiency of M-MFC observed during the experiment was 76.9%. The inadequacy of terminal electron acceptor in the cathodic chamber in M-MFC might have hampered the electron transfer, which in turn, led to slower specific microbial activity, thereby resulting in lower COD removal efficiency than the traditional MFC with aerated catholyte. The average operating voltage (OV) and open-circuit voltage (OCV) of 294 mV and 594 mV, respectively, were observed in M-MFC. The maximum power density observed during polarization was 381 mW/m³, and the maximum sustainable power density observed during the experiment was 397 mW/m³ in M-MFC. The maximum normalized energy recovery and coulombic efficiency of 38.09 Wh/m³ and 1.27%, respectively, were observed. Therefore, it was evidenced that rhizospheric oxygen release of wetland macrophytes (C. indica) was capable of sustaining the cathodic reaction in MFC for field-scale applications.

Keywords: hydroponic, microbial fuel cell, rhizospheric oxygen release, wetland macrophytes

Procedia PDF Downloads 117

Authors: Avadhesh Yadav, Balram Manoj Kumar

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A solar powered air heating system using parabolic trough collector was experimentally investigated. In this experimental setup, the reflected solar radiations were focused on absorber tube which was placed at focal length of the parabolic trough. In this setup, air was used as working fluid which collects the heat from absorber tube. To enhance the performance of parabolic trough, collector with different type of reflectors were used. It was observed for aluminum sheet maximum temperature is 52.3ºC, which 24.22% more than steel sheet as reflector and 8.5% more than aluminum foil as reflector, also efficiency by using Aluminum sheet as reflector compared to steel sheet as reflector is 61.18% more. Efficiency by using aluminum sheet as reflector compared to aluminum foil as reflector is 18.98% more.

Keywords: parabolic trough collector, reflectors, air flow rates, solar power, aluminum sheet

Procedia PDF Downloads 346

Authors: Thana Ananacha

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This paper reports the numerical and experimental performances of Double Glass Wall are investigated. Two configurations were considered namely, the Double Clear Glass Wall (DCGW) and the Double Translucent Glass Wall (DTGW). The coupled governing equations as well as boundary conditions are solved using the finite element method (FEM) via COMSOLTM Multiphysics. Temperature profiles and flow field of the DCGW and DTGW are reported and discussed. Different constant heat fluxes were considered namely 400 and 800 W.m-2 the corresponding initial condition temperatures were to 30.5 and 38.5 ºC respectively. The results show that the simulation results are in agreement with the experimental data. Conclusively, the model considered in this study could reasonable be used simulate the thermal and ventilation performance of the DCGW and DTGW configurations.

Keywords: thermal simulation, Double Glass Wall, velocity field, finite element method (FEM)

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Authors: Stephen Kirkup

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This paper discusses the implementation of the boundary element method (BEM) on an Excel spreadsheet and how it can be used in teaching vector calculus and simulation. There are two separate spreadheets, within which Laplace equation is solved by the BEM in two dimensions (LIBEM2) and axisymmetric three dimensions (LBEMA). The main algorithms are implemented in the associated programming language within Excel, Visual Basic for Applications (VBA). The BEM only requires a boundary mesh and hence it is a relatively accessible method. The BEM in the open spreadsheet environment is demonstrated as being useful as an aid to teaching and learning. The application of the BEM implemented on a spreadsheet for educational purposes in introductory vector calculus and simulation is explored. The development of assignment work is discussed, and sample results from student work are given. The spreadsheets were found to be useful tools in developing the students’ understanding of vector calculus and in simulating heat conduction.

Keywords: boundary element method, Laplace’s equation, vector calculus, simulation, education

Procedia PDF Downloads 146

Authors: Khulood Miliany

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This study examines the media habits of young people in Saudi Arabia, in particular their use of the Internet and television in the domestic sphere, and how use of the Internet impacts upon other activities. In order to address the research questions, focus group interviews were conducted with Saudi university students. The study found that television has become a central part of social life within the household where television represents a main source for family time, particularly in Ramadan while the Internet is a solitary activity where it is used in more private spaces. Furthermore, Saudi females were also more likely to have their Internet access monitored and circumscribed by family members, with parents controlling the location and the amount of time spent using the Internet.

Keywords: domestication of technology, internet, social context, television, young people

Procedia PDF Downloads 281

Authors: Sara Soltanpour, Adolfo Foriero

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Frost heave is arguably the most problematic adverse phenomenon in cold region areas. Frost heave is a complex process that depends on heat and water transfer. These coupled physical fields generate considerable heave stresses as well as deformations. In the present study, a coupled thermal-hydraulic-mechanical (THM) model using COMSOL Multiphysics in frozen unsaturated soils, such as fine sand, is investigated. Particular attention to the frost heave and temperature distribution, as well as the water migrating during soil freezing, is assessed. The results obtained from the numerical simulations are consistent with the results measured in the full-scale tests conducted by Cold Regions Research and Engineering Laboratory (CRREL).

Keywords: frost heave, numerical simulations, COMSOL software, unsaturated freezing soil

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Authors: Abdelhalim Kessal, Ali Chebabhi

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In this paper, a controller based on fuzzy logic control (FLC) associated to Three Dimensional Space Vector Modulation (3DSVM) is applied for shunt active filter in αβo axes domain. The main goals are to improve power quality under disturbed loads, minimize source currents harmonics and reduce neutral current magnitude in the four-wire structure. FLC is used to obtain the reference current and control the DC-bus voltage at the inverter output. The switching signals of the four-leg inverter are generating through a Three Dimensional Space Vector Modulation (3DSVM). Selected simulation results have been shown to validate the proposed system.

Keywords: flc, 3dsvm, sapf, harmonic, inverter

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Authors: Terence Soule, Tami Al Ghamdi

Abstract:

To study how the partial knowledge transfer may affect the Genetic Algorithm (GA) performance, we model the Transfer Learning (TL) process using GA as the model solver. The objective of the TL is to transfer the knowledge from one problem to another related problem. This process imitates how humans think in their daily life. In this paper, we proposed to study a case where the knowledge transferred from the S problem has less information than what the T problem needs. We sampled the transferred population using different strategies of TL. The results showed transfer part of the knowledge is helpful and speeds the GA process of finding a solution to the problem.

Keywords: transfer learning, partial transfer, evolutionary computation, genetic algorithm

Procedia PDF Downloads 116

Authors: Laila Almulla

Abstract:

As native plants are better adapted to the local environment, can endure long spells of drought, withstand high soil salinity levels and provide a more natural effect to landscape projects, their use in landscape projects are gaining popularity. Standardization of seed germination methods and raising the hardened plants of selected native plants for their use in landscape projects will both conserve natural resources and produce sustainable greenery. In the present study, Haloxylon salicornicum, a perennial herb with a potential use for urban greenery was selected for seed germination tests as there is an urgent need to mass multiply them for their large-scale use. Among the nine treatments tried with different concentrations of gibberelic acid (GA3) and dry heat, the seeds responded with treatments when the wings were removed. The control as well as 250 GA3 treatments produced the maximum germination of 86%.

Keywords: dormancy, gibberelic acid, germination trays , vigor index

Procedia PDF Downloads 381