Search results for: Surface runoff water

Authors: Abdulsalam. I. Rafida, Ehae. Abo-Jnha, Kald. Tainah

Abstract:

This study mainly aims at assessing the level of microbial pollution of the water used in the chair system in dental clinics. For this purpose 36 samples have been randomly collected from a number of dental surgeries in the city of Tripoli in Libya. However, 32 of the samples have tested positive to microbial pollution including 13 of the samples, which have tested positives to Pseudomonas aeruginosa. Based on the results of the test a further investigation of the biofilms incorporated within the dental chair system has been conducted. The laboratory tests of biofilms with similar design to those found in dental chairs have proved that bacterial pollution takes place through saliva of the patients who use the chairs, and that this saliva is rich with nutrients which provides a suitable breeding ground for all types of bacteria.

Keywords: Pseudomonas aeruginosa, Biofilm.

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Authors: Mateus N. Esperança, Marcel O. Cerri, Alberto C. Badino

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The performance of airlift bioreactors are closely related with their geometry, especially the gas-liquid separator design. In this study, the influence of the gas-liquid separator geometry on oxygen transfer and gas hold-up was evaluated in 10-L concentric-tube airlift bioreactor operating with distilled water and xanthan gum solution. The specific airflow rate (ɸ_AIR) exhibited the higher effect on the oxygen transfer coefficient (k_La) for both fluids. While the gas-liquid separator openness angle (α) and liquid volume fraction on the gas-liquid separator (V_GLS) have presented opposite effects on oxygen mass transfer, they affected negatively the global gas hold-up of distilled water system. The best degassing zone geometry corresponded to a 90° openness angle with 10% of the liquid on it.

Keywords: Airlift bioreactor, gas holdup, gas-liquid separator, oxygen transfer.

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Authors: Mojtaba Ghodsi, Hamidreza Ziaifar, Morteza Mohammadzaheri, Payam Soltani

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This article presents an analytical model to estimate the harvested power from a Magnetostrictive cantilevered beam with tip excitation. Furthermore, the effects of internal and external damping on harvested power are investigated. The magnetostrictive material in this harvester is Galfenol. In comparison to other popular smart materials like Terfenol-D, Galfenol has higher strength and machinability. In this article, first, a mechanical model of the Euler-Bernoulli beam is employed to calculate the deflection of the harvester. Then, the magneto-mechanical equation of Galfenol is combined with Faraday's law to calculate the generated voltage of the Magnetostrictive cantilevered beam harvester. Finally, the beam model is incorporated in the aforementioned combination. The results show that a 30×8.5×1 mm Galfenol cantilever beam harvester with 80 turn pickup coil can generate up to 3.7 mV and 9 mW. Furthermore, sensitivity analysis made by Response Surface Method (RSM) shows that the harvested power is only sensitive to the internal damping coefficient.

Keywords: Internal damping coefficient, external damping coefficient, Euler-Bernoulli, energy harvester, Galfenol, magnetostrictive, response surface method.

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Authors: M.S.Nourbakhsh, M.E.khosroshahi

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Gold coated silica core nanoparticles have an optical response dictated by the plasmon resonance. The wavelength at which the resonance occurs depends on the core and shell sizes, allowing nanoshells to be tailored for particular applications. The purposes of this study was to synthesize and use different concentration of gold nanoshells as exogenous material for skin tissue soldering and also to examine the effect of laser soldering parameters on the properties of repaired skin. Two mixtures of albumin solder and different concentration of gold nanoshells were prepared. A full thickness incision of 2×20 mm2 was made on the surface and after addition of mixtures it was irradiated by an 810nm diode laser at different power densities. The changes of tensile strength σt due to temperature rise, number of scan (Ns), and scan velocity (Vs) were investigated. The results showed at constant laser power density (I), σt of repaired incisions increases by increasing the concentration of gold nanoshells, Ns and decreasing Vs. It is therefore important to consider the trade off between the scan velocity and the surface temperature for achieving an optimum operating condition. In our case this corresponds to σt =1610 gr/cm2 at I~ 60 Wcm-2, T ~ 65ºC, Ns =10 and Vs=0.2mms-1.

Keywords: Tissue soldering, Diode laser, Gold Nanoshells, Tensile strength

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Authors: Norasiah Muhammad, Yupiter HP Manurung

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This paper investigates the development of weld zone in Resistance Spot Welding (RSW) which focuses on weld nugget and Heat Affected Zone (HAZ). The effects of four factors namely weld current, weld time, electrode force and hold time were studied using a general 24 factorial design augmented by five centre points. The results of the analysis showed that all selected factors except hold time exhibit significant effect on weld nugget radius and HAZ size. Optimization of the welding parameters (weld current, weld time and electrode force) to normalize weld nugget and to minimize HAZ size was then conducted using Central Composite Design (CCD) in Response Surface Methodology (RSM) and the optimum parameters were determined. A regression model for radius of weld nugget and HAZ size was developed and its adequacy was evaluated. The experimental results obtained under optimum operating conditions were then compared with the predicted values and were found to agree satisfactorily with each other

Keywords: Factorial design, Optimization, Resistance Spot Welding (RSW), Response Surface Methodology (RSM).

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Authors: Yasir M. Alyazichi, Brian G. Jones, Errol McLean, Hamd N. Altalyan, Ali K. M. Al-Nasrawi

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The main purpose of this study is to assess the sediment quality and potential ecological risk in marine sediments in Gymea Bay located in south Sydney, Australia. A total of 32 surface sediment samples were collected from the bay. Current track trajectories and velocities have also been measured in the bay. The resultant trace elements were compared with the adverse biological effect values Effect Range Low (ERL) and Effect Range Median (ERM) classifications. The results indicate that the average values of chromium, arsenic, copper, zinc, and lead in surface sediments all reveal low pollution levels and are below ERL and ERM values. The highest concentrations of trace elements were found close to discharge points and in the inner bay, and were linked with high percentages of clay minerals, pyrite and organic matter, which can play a significant role in trapping and accumulating these elements. The lowest concentrations of trace elements were found to be on the shoreline of the bay, which contained high percentages of sand fractions. It is postulated that the fine particles and trace elements are disturbed by currents and tides, then transported and deposited in deeper areas. The current track velocities recorded in Gymea Bay had the capability to transport fine particles and trace element pollution within the bay. As a result, hydrodynamic measurements were able to provide useful information and to help explain the distribution of sedimentary particles and geochemical properties. This may lead to knowledge transfer to other bay systems, including those in remote areas. These activities can be conducted at a low cost, and are therefore also transferrable to developing countries. The advent of portable instruments to measure trace elements in the field has also contributed to the development of these lower cost and easily applied methodologies available for use in remote locations and low-cost economies.

Keywords: Current track velocities, Gymea Bay, surface sediments, trace elements.

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Authors: Sabri Mrayed, David Maccioni, Greg Leslie

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Seawater desalination has been accepted as one of the most effective solutions to the growing problem of a diminishing clean drinking water supply. Currently two desalination technologies dominate the market – the thermally driven multi-stage flash distillation (MSF) and the membrane based reverse osmosis (RO). However, in recent years membrane distillation (MD) has emerged as a potential alternative to the established means of desalination. This research project intended to determine the viability of MD as an alternative process to MSF and RO for seawater desalination. Specifically the project involves conducting thermodynamic analysis of the process based on the second law of thermodynamics to determine the efficiency of the MD. Data was obtained from experiments carried out on a laboratory rig. To determine exergy values required for the exergy analysis, two separate models were built in Engineering Equation Solver – the ’Minimum Separation Work Model’ and the ‘Stream Exergy Model’. The efficiency of MD process was found to be 17.3 % and the energy consumption was determined to be 4.5 kWh to produce one cubic meter of fresh water. The results indicate MD has potential as a technique for seawater desalination compared to RO and MSF. However it was shown that this was only the case if an alternate energy source such as green or waste energy was available to provide the thermal energy input to the process. If the process was required to power itself, it was shown to be highly inefficient and in no way thermodynamically viable as a commercial desalination process.

Keywords: Desalination, Exergy, Membrane distillation, Second law efficiency.

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Authors: N. Hatraf, N. Moummi

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The interest in air conditioning using renewable energies is increasing. The thermal energy produced from the solar energy can be converted to useful cooling and heating through the thermochemical or thermophysical processes by using thermally activated energy conversion systems. The ambient air contains so much water that very high dehumidification rates are required. For a continuous dehumidification of the process air, the water adsorbed on the desiccant material has to be removed, which is done by allowing hot air to flow through the desiccant material (regeneration). A solid desiccant cooling system transfers moisture from the inlet air to the silica gel by using two processes: Absorption process and the regeneration process. The main aim of this paper is to study how the dehumidification rate, the generation temperature and many other factors influence the efficiency of a solid desiccant system by using TRNSYS software. The results show that the desiccant system could be used to decrease the humidity rate of the entering air.

Keywords: Dehumidification, efficiency, humidity, TRNSYS.

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Authors: Chia-Chih Wei, Yun-Qi Li, Ssu-Ying Chen, Hsuan-Jung Chen, Hsi-Wen Yang, Chih-Yuan Chen, Chien-Chon Chen

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In this paper, we used a high-quality anodization technique to make a colored wind chime with a nano-tube structure anodic film, which controls the length-to-diameter ratio of an aluminum rod and controls the oxide film structure on the surface of the aluminum rod by an anodizing method. The research experiment used hard anodization to grow a controllable thickness of anodic film on an aluminum alloy surface. The hard anodization film has high hardness, high insulation, high-temperature resistance, good corrosion resistance, colors, and mass production properties that can be further applied to transportation, electronic products, biomedical fields, or energy industry applications. This study also provides in-depth research and a detailed discussion of the related process of aluminum alloy surface hard anodizing, including pre-anodization, anodization, and post-anodization. The experiment parameters of anodization include using a mixed acid solution of sulfuric acid and oxalic acid as an anodization electrolyte and controlling the temperature, time, current density, and final voltage to obtain the anodic film. In the results of the experiments, the properties of the anodic film, including thickness, hardness, insulation, and corrosion characteristics, the microstructure of the anode film were measured, and the hard anodization efficiency was calculated. Thereby it can obtain different transmission speeds of sound in the aluminum rod. And, different audio sounds can present on the aluminum rod. Another feature of the present experiment result is the use of the anodizing method and dyeing method, laser engraving patterning and electrophoresis method to make good-quality colored aluminum wind chimes.

Keywords: Anodization, aluminum, wind chime, nano-tube.

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Authors: S. Abdourraziq, R. El Bachtiri

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The use of solar energy as a source for pumping water is one of the promising areas in the photovoltaic (PV) application. The energy of photovoltaic pumping systems (PVPS) can be widely improved by employing an MPPT algorithm. This will lead consequently to maximize the electrical motor speed of the system. This paper presents a modified incremental conductance (IncCond) MPPT algorithm with direct control method applied to a standalone PV pumping system. The influence of the algorithm parameters on system behavior is investigated and compared with the traditional (INC) method. The studied system consists of a PV panel, a DC-DC boost converter, and a PMDC motor-pump. The simulation of the system by MATLAB-SIMULINK is carried out. Simulation results found are satisfactory.

Keywords: Photovoltaic pumping system (PVPS), incremental conductance (INC), MPPT algorithm, boost converter.

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Authors: S. Mahdi S. Kolbadi, Ramezan Ali Alvand, Afrasiab Mirzaei

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In this study, to investigate and analyze the seismic behavior of concrete in open rectangular water storage tanks in two-dimensional and three-dimensional spaces, the Finite Element Method has been used. Through this method, dynamic responses can be investigated together in fluid storages system. Soil behavior has been simulated using tanks boundary conditions in linear form. In this research, in addition to flexibility of wall, the effects of fluid-structure interaction on seismic response of tanks have been investigated to account for the effects of flexible foundation in linear boundary conditions form, and a dynamic response of rectangular tanks in two-dimensional and three-dimensional spaces using finite element method has been provided. The boundary conditions of both rigid and flexible walls in two-dimensional finite element method have been considered to investigate the effect of wall flexibility on seismic response of fluid and storage system. Furthermore, three-dimensional model of fluid-structure interaction issue together with wall flexibility has been analyzed under the three components of earthquake. The obtained results show that two-dimensional model is also accurately near to the results of three-dimension as well as flexibility of foundation leads to absorb received energy and relative reduction of responses.

Keywords: Dynamic behavior, water storage tank, fluid-structure interaction, flexible wall.

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Authors: M. N. N. Hisyamudin, S. Yokoyama, M. Umemoto

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In this study, an experimental investigation was carried out to fix CO2 into the electronic arc furnace (EAF) reducing slag from stainless steelmaking process under wet grinding. The slag was ground by the vibrating ball mill with the CO2 and pure water. The reaction behavior was monitored with constant pressure method, and the change of CO2 volume in the experimental system with grinding time was measured. It was found that the CO2 absorption occurred as soon as the grinding started. The CO2 absorption under wet grinding was significantly larger than that under dry grinding. Generally, the amount of CO2 absorption increased as the amount of water, the amount of slag, the diameter of alumina ball and the initial pressure of CO2 increased. However, the initial absorption rate was scarcely influenced by the experimental conditions except for the initial CO2 pressure. According to this research, the CO2 reacted with the CaO inside the slag to form CaCO3.

Keywords: CO2 absorption, EAF reducing slag, vibration ball mill, wet grinding.

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Authors: Fatema Akram, Mohammad G. Rasul, M. Masud K. Khan, M. Sharif I. I. Amir

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Australia is a country of some 7,700 million square kilometers with a population of about 22.6 million. At present water security is a major challenge for Australia. In some areas the use of water resources is approaching and in some parts it is exceeding the limits of sustainability. A focal point of proposed national water conservation programs is the recycling of both urban stormwater and treated wastewater. But till now it is not widely practiced in Australia, and particularly stormwater is neglected. In Australia, only 4% of stormwater and rainwater is recycled, whereas less than 1% of reclaimed wastewater is reused within urban areas. Therefore, accurately monitoring, assessing and predicting the availability, quality and use of this precious resource are required for better management. As stormwater is usually of better quality than untreated sewage or industrial discharge, it has better public acceptance for recycling and reuse, particularly for non-potable use such as irrigation, watering lawns, gardens, etc. Existing stormwater recycling practice is far behind of research and no robust technologies developed for this purpose. Therefore, there is a clear need for using modern technologies for assessing feasibility of stormwater harvesting and reuse. Numerical modeling has, in recent times, become a popular tool for doing this job. It includes complex hydrological and hydraulic processes of the study area. The hydrologic model computes stormwater quantity to design the system components, and the hydraulic model helps to route the flow through stormwater infrastructures. Nowadays water quality module is incorporated with these models. Integration of Geographic Information System (GIS) with these models provides extra advantage of managing spatial information. However for the overall management of a stormwater harvesting project, Decision Support System (DSS) plays an important role incorporating database with model and GIS for the proper management of temporal information. Additionally DSS includes evaluation tools and Graphical user interface. This research aims to critically review and discuss all the aspects of stormwater harvesting and reuse such as available guidelines of stormwater harvesting and reuse, public acceptance of water reuse, the scopes and recommendation for future studies. In addition to these, this paper identifies, understand and address the importance of modern technologies capable of proper management of stormwater harvesting and reuse.

Keywords: Stormwater Management, Stormwater Harvesting and Reuse, Numerical Modeling, Geographic Information System (GIS), Decision Support System (DSS), Database.

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Authors: R. Karmouch

Abstract:

A thin gold metal layer was deposited on the top of silicon oxide films containing embedded Si nanocrystals (Si-nc). The sample was annealed in a gas containing nitrogen, and subsequently characterized by photoluminescence. We obtained 3-fold enhancement of photon emission from the Si-nc embedded in silicon dioxide covered with a Gold layer as compared with an uncovered sample. We attribute this enhancement to the increase of the spontaneous emission rate caused by the coupling of the Si-nc emitters with the surface plasmons (SP). The evolution of PL emission with laser irradiated time was also collected from covered samples, and compared to that from uncovered samples. In an uncovered sample, the PL intensity decreases with time, approximately with two decay constants. Although the decrease of the initial PL intensity associated with the increase of sample temperature under CW pumping is still observed in samples covered with a gold layer, this film significantly contributes to reduce the permanent deterioration of the PL intensity. The resistance to degradation of light-emitting silicon nanocrystals can be increased by SP coupling to suppress the permanent deterioration. Controlling the permanent photodeterioration can allow to perform a reliable optical gain measurement.

Keywords: Photodeterioration, Silicon Nanocrystals, Ion Implantation, Photoluminescence, Surface Plasmons.

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Authors: R. Prakash, B. Meenakshipriya, R. Kumaravelan

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Fresh water is one of the resources which is getting depleted day by day. A wise method to address this issue is by the application of renewable energy-sun irradiation and by means of decentralized, cheap, energetically self-sufficient, robust and simple to operate plants, distillates can be obtained from sea, river or even sewage. Solar desalination is a technique used to desalinate water using solar energy. The present work deals with the comprehensive design and simulation of solar tracking system using LabVIEW, temperature and mass flow rate control of the solar desalination plant using LabVIEW and also analysis of single phase inverter circuit with LC filters for solar pumping system in MATLAB. The main objective of this work is to improve the performance of solar desalination system using automatic tracking system, output control using temperature and mass flow rate control system and also to reduce the harmonic distortion in the solar pumping system by means of LC filters. The simulation of single phase inverter was carried out using MATLAB and the output waveforms were analyzed. Simulations were performed for optimum output temperature control, which in turn controls the mass flow rate of water in the thermal collectors. Solar tracking system was accomplished using LABVIEW and was tested successfully. The thermal collectors are tracked in accordance with the sun’s irradiance levels, thereby increasing the efficiency of the thermal collectors.

Keywords: Desalination, Electro dialysis, LabVIEW, MATLAB, PWM inverter, Reverse osmosis.

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Authors: R. Ziaie Moayed, E. Ghanbari Alamouty

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Deep soil mixing is one of the improvement methods in geotechnical engineering which is widely used in soft soils. This article investigates the consolidation behavior of a soft clay soil which is improved by soil-cement column (SCC) by numerical modeling using Plaxis2D program. This behavior is simulated under vertical static and cyclic load which is applied on the soil surface. The static load problem is the simulation of a physical model test in an axisymmetric condition which uses a single SCC in the model center. The results of numerical modeling consist of settlement of soft soil composite, stress on soft soil and column, and excessive pore water pressure in the soil show a good correspondence with the test results. The response of soft soil composite to the cyclic load in vertical direction also compared with the static results. Also the effects of two variables namely the cement content used in a SCC and the area ratio (the ratio of the diameter of SCC to the diameter of composite soil model, a) is investigated. The results show that the stress on the column with the higher value of a, is lesser compared with the stress on other columns. Different rate of consolidation and excessive pore pressure distribution is observed in cyclic load problem. Also comparing the results of settlement of soil shows higher compressibility in the cyclic load problem.

Keywords: Area ratio, consolidation behavior, cyclic load, numerical modeling, soil-cement column.

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Authors: R. Aminzadeh, M. Abarzani, J. Sargolzaei

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In this study, the kinetics of osmotic dehydration of melons (Tille variety) in a ternary system followed by air-drying for preserving melons in the summer to be used in the winter were investigated. The effect of different osmotic solution concentrations 30, 40 and 50% (w/w) of sucrose with 10% NaCl salt and fruit to solution ratios 1:4, 1:5 and 1:6 on the mass transfer kinetics during osmotic dehydration of melon in ternary solution namely sucrosesalt- water followed by air-drying were studied. The diffusivity of water during air-drying was enhanced after the fruit samples were immersed in the osmotic solution after 60 min. Samples non-treated and pre-treated during one hour in osmotic solutions with 60% (w/w) of sucrose with 10% NaCl salt and fruit to solution ratio of 1:4 were dried in a hot air-dryer at 60oC (2 m/s) until equilibrium was achieved.

Keywords: Air drying, Effective diffusion coefficient, Mass transfer kinetic, Melon, Osmotic dehydration.

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Authors: A. S. Kipcak, O. Dere Ozdemir, E. Moroydor Derun, M. B. Piskin

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Tea has several types of essential elements. Potassium, magnesium and phosphorus are some examples of these elements. Tea is widely used drink in Turkey, also some people puts a lemon wedge to tea for different taste. In this study potassium, magnesium and phosphorus contents after the hot water brewing of black and green tea were determined by Optical Emission Spectroscopy (ICPOES). Furthermore, how the lemon addition to teas affects the concentrations of the potassium, magnesium and phosphorus amount are investigated. From the results, potassium, magnesium and phosphorus concentrations are found as 3003.3, 597.1, 1167.2 ppm in black tea and 3718.0, 3830.5, 376.4 ppm in green tea, respectively. After lemon addition potassium, magnesium and phosphorus concentrations are changed to 14930, 830.4, 1113.5 ppm in black tea and 15460.0, 909.5, 1152.5 ppm in green tea, respectively. It is seen that lemon addition affects some essential elements in black and green Turkish teas.

Keywords: Hot water brewing, ICP-OES, lemon, tea

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Authors: A. Magesh, B. Preetha, T. Viruthagiri

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Direct fermentation of 226 white rose tapioca stem to ethanol by Fusarium oxysporum was studied in a batch reactor. Fermentation of ethanol can be achieved by sequential pretreatment using dilute acid and dilute alkali solutions using 100 mesh tapioca stem particles. The quantitative effects of substrate concentration, pH and temperature on ethanol concentration were optimized using a full factorial central composite design experiment. The optimum process conditions were then obtained using response surface methodology. The quadratic model indicated that substrate concentration of 33g/l, pH 5.52 and a temperature of 30.13oC were found to be optimum for maximum ethanol concentration of 8.64g/l. The predicted optimum process conditions obtained using response surface methodology was verified through confirmatory experiments. Leudeking-piret model was used to study the product formation kinetics for the production of ethanol and the model parameters were evaluated using experimental data.

Keywords: Fusarium oxysporum, Lignocellulosic biomass, Product formation kinetics, Statistical experimental design

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Authors: S. Jamshidi, E. Feizi Ashtiani, M. Ardestani

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Waste Load Allocation (WLA) strategies usually intend to find economic policies for water resource management. Water quality trading (WQT) is an approach that uses discharge permit market to reduce total environmental protection costs. This primarily requires assigning discharge limits known as total maximum daily loads (TMDLs). These are determined by monitoring organizations with respect to the receiving water quality and remediation capabilities. The purpose of this study is to compare two approaches of TMDL assignment for WQT policy in small catchment area of Haraz River, in north of Iran. At first, TMDLs are assigned uniformly for the whole point sources to keep the concentrations of BOD and dissolved oxygen (DO) at the standard level at checkpoint (terminus point). This was simply simulated and controlled by Qual2kw software. In the second scenario, TMDLs are assigned using multi objective particle swarm optimization (MOPSO) method in which the environmental violation at river basin and total treatment costs are minimized simultaneously. In both scenarios, the equity index and the WLA based on trading discharge permits (TDP) are calculated. The comparative results showed that using economically optimized TMDLs (2nd scenario) has slightly more cost savings rather than uniform TMDL approach (1st scenario). The former annually costs about 1 M$ while the latter is 1.15 M$. WQT can decrease these annual costs to 0.9 and 1.1 M$, respectively. In other word, these approaches may save 35 and 45% economically in comparison with command and control policy. It means that using multi objective decision support systems (DSS) may find more economical WLA, however its outcome is not necessarily significant in comparison with uniform TMDLs. This may be due to the similar impact factors of dischargers in small catchments. Conversely, using uniform TMDLs for WQT brings more equity that makes stakeholders not feel that much envious of difference between TMDL and WQT allocation. In addition, for this case, determination of TMDLs uniformly would be much easier for monitoring. Consequently, uniform TMDL for TDP market is recommended as a sustainable approach. However, economical TMDLs can be used for larger watersheds.

Keywords: Waste load allocation (WLA), Water quality trading (WQT), Total maximum daily loads (TMDLs), Haraz River, Multi objective particle swarm optimization (MOPSO), Equity.

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Authors: Hankun Lin, Yiqiang Xiao, Qiaosheng Zhan

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Shading devices (SDs) are widely used in buildings in the hot-humid climate areas for reducing cooling energy consumption for interior temperature, as the result of reducing the solar radiation directly. Contrasting the surface temperature of materials of SDs to the glass on the building façade could give more analysis for the shading effect. On the other side, SDs are much more used as the independence system on building façade in hot-humid area. This typical construction could have some impacts on building ventilation as well. This paper discusses the outdoor SDs’ effects on the building thermal environment and ventilation, through a set of measurements on a 2-floors office building in Guangzhou, China, which install a dynamic aluminum SD-system around the façade on 2^nd-floor. The measurements recorded the in/outdoor temperature, relative humidity, velocity, and the surface temperature of the aluminum panel and the glaze. After that, a CFD simulation was conducted for deeper discussion of ventilation. In conclusion, this paper reveals the temperature differences on the different material of the façade, and finds that the velocity of indoor environment could be reduced by the outdoor SDs.

Keywords: Outdoor shading devices, hot-humid area, temperature, ventilation, measurement, CFD.

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Authors: Tianlai Yu, Zhengguo Yuan, Sidi Shan

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Adopting the measured constitutive relationship of stress-strain of river ice, the finite element analysis model of percussive force of river ice and pier is established, by the explicit dynamical analysis software package LS-DYNA. Effects of element types, contact method and arithmetic of ice and pier, coupled modes between different elements, mesh density of pier, and ice sheet in contact area on the collision force are studied. Some of measures for the collision force analysis of river ice and pier are proposed as follows: bridge girder can adopt beam161 element with 3-node; pier below the line of 1.30m above ice surface and ice sheet use solid164 element with 8-node; in order to accomplish the connection of different elements, the rigid body with 0.01-0.05m thickness is defined between solid164 and beam161; the contact type of ice and pier adopts AUTOMATIC_SURFACE_TO_SURFACE, using symmetrical penalty function algorithms; meshing size of pier below the line of 1.30m above ice surface should not less than 0.25×0.25×0.5m3. The simulation results have the advantage of high precision by making a comparison between measured and computed data. The research results can be referred for collision force study between river ice and pier.

Keywords: River ice, collision force, simulation analysis, ANSYS/LS-DYNA

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Authors: Hussain H. Al-Kayiem, Ahmed K. Hussein, Toh Seng Peow

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The evaluation of the convective heat transfer of flow in passages with rectangular cross section is still of interest for the heat transfer investigators, as in the air heater solar collectors. The aim of this paper is to present investigation results on the natural convection heat transfer in a solar air heater. The effect of the channel length as heat transfer surface and the inclination of the passage were investigated. The results were obtained experimentally and theoretically. For that, an experimental test rig was fabricated with channel lengths of 1m, 1.5m, and 2m. For each length, the air outlet and inlet temperatures, absorber and cover temperatures, solar radiation intensity and air flow rate were measured at 10o, 30o, 50o, 70o, and 90o tilt angles. Measurements were recorded every 2 hours interval to investigate the transient behavior of the system. The experimental and theoretical results are presented in terms of Nu number versus Ra number and discussed. The percentages of differences between experimental and theoretical results are within the margin of 6% to 13%, effectively. It is recommended to extend the investigation to study the same configurations with different artificial surface roughing by ribs or pins.

Keywords: Convective heat transfer, Flat plate, Natural convection, Passage flow, Solar energy.

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Authors: Reza Eslami-Farsani, Hamed Khosravi, Saba Fayazzadeh

Abstract:

Lightweight and efficient structures have the aim to enhance the efficiency of the components in various industries. Toward this end, composites are one of the most widely used materials because of durability, high strength and modulus, and low weight. One type of the advanced composites is grid-stiffened composite (GSC) structures, which have been extensively considered in aerospace, automotive, and aircraft industries. They are one of the top candidates for replacing some of the traditional components, which are used here. Although there are a good number of published surveys on the design aspects and fabrication of GSC structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Matrix modification using nanoparticles is an effective method to enhance the flexural properties of the fibrous composites. In the present study, a silanecoupling agent (3-glycidoxypropyltrimethoxysilane/3-GPTS) was introduced onto the silica (SiO2) nanoparticle surface and its effects on the three-point flexural response of isogrid E-glass/epoxy composites were assessed. Based on the Fourier Transform Infrared Spectrometer (FTIR) spectra, it was inferred that the 3-GPTS coupling agent was successfully grafted onto the surface of SiO2 nanoparticles after modification. Flexural test revealed an improvement of 16%, 14%, and 36% in stiffness, maximum load and energy absorption of the isogrid specimen filled with 3 wt.% 3- GPTS/SiO2 compared to the neat one. It would be worth mentioning that in these structures, considerable energy absorption was observed after the primary failure related to the load peak. In addition, 3- GPTMS functionalization had a positive effect on the flexural behavior of the multiscale isogrid composites. In conclusion, this study suggests that the addition of modified silica nanoparticles is a promising method to improve the flexural properties of the gridstiffened fibrous composite structures.

Keywords: Isogrid-stiffened composite panels, silica nanoparticles, surface modification, flexural properties.

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Authors: Hendriëtte van der Walt, Lesley Chown, Richard Harris, Ndabenhle Sosibo, Robert Tshikhudo

Abstract:

The use of magnetic and magnetic/gold core/shell nanoparticles in biotechnology or medicine has shown good promise due to their hybrid nature which possesses superior magnetic and optical properties. Some of these potential applications include hyperthermia treatment, bio-separations, diagnostics, drug delivery and toxin removal. Synthesis refinement to control geometric and magnetic/optical properties, and finding functional surfactants for biomolecular attachment, are requirements to meet application specifics. Various high-temperature preparative methods were used for the synthesis of iron oxide and gold-coated iron oxide nanoparticles. Different surface functionalities, such as 11-aminoundecanoic and 11-mercaptoundecanoic acid, were introduced on the surface of the particles to facilitate further attachment of biomolecular functionality and drug-like molecules. Nanoparticle thermal stability, composition, state of aggregation, size and morphology were investigated and the results from techniques such as Fourier Transform-Infra Red spectroscopy (FT-IR), Ultraviolet visible spectroscopy (UV-vis), Transmission Electron Microscopy (TEM) and thermal analysis are discussed.

Keywords: Core/shell, Iron oxide, Gold coating, Nanoparticles.

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Authors: Md. Sharif Imam Ibne Amir, M. Shah Alam Khan, Mohammad Masud Kamal Khan, Mohammad Golam Rasul, Fatema Akram

Abstract:

The problems of severe drainage congestion and water logging in the southwestern Bangladesh have been solved by an innovative concept, Tidal River Management (TRM). TRM involves the uniform raising of the land inside a tidal basin (beel) while simultaneously maintaining the proper drainage capacity in the river. The present practice of TRM is to link the river with the selected beel by constructing a link canal at the entrance of which most of the sedimentation takes place. This localized sedimentation also creates drainage congestion and water logging making it unattractive to landowners who participate in the program. In this paper a functional sediment management plan is presented to get rid of this problem

Keywords: Beel, embankment, MIKE 21 Flow Model FM, Tidal River Management.

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Authors: Chien-Yeh Hsu, Yuan-Ching Chiang, Zi-Jie Chien, Sih-Li Chen

Abstract:

In this study, a field experiment and performance analysis of air-tunnel heat exchanger integrated with water-filled raft foundation of residential building were performed. In order to obtain better performance, conventional applications of air-tunnel inevitably have high initial cost or issues about insufficient installation space. To improve the feasibility of air tunnel heat exchanger in high-density housing, an integrated system consisting of air pipes immersed in the water-filled raft foundation was presented, taking advantage of immense amount of water and relatively stable temperature in raft foundation of building. The foundation-integrated air tunnel was applied to a residential building located in Yilan, Taiwan, and its thermal performance was measured in the field experiment. The results indicated that the cooling potential of integrated system was close to the potential of soil-based EAHE at 2 m depth or deeper. An analytical model based on thermal resistance method was validated by measurement results, and was used to carry out the dimensioning of foundation-integrated air tunnel. The discrepancies between calculated value and measured data were less than 2.7%. In addition, the return-on-investment with regard to thermal performance and economics of the application was evaluated. Because the installation for air tunnel is scheduled in the building foundation construction, the utilization of integrated system spends less construction cost compare to the conventional earth-air tunnel.

Keywords: Air tunnel, ground heat exchanger, raft foundation, residential building.

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Authors: Zs. J. Becze, Á. Krivián, M. Sárvári

Abstract:

Hybrid selection and the application of hybrid specific production technologies are important in terms of the increase of the yield and crop safety of maize. The main explanation for this is climate change, since weather extremes are going on and seem to accelerate in Hungary too.

The biological bases, the selection of appropriate hybrids will be of greater importance in the future. The issue of the adaptability of hybrids will be considerably appreciated. Its good agronomical traits and stress bearing against climatic factors and agrotechnical elements (e.g. different types of herbicides) will be important. There have been examples of 3-4 consecutive droughty years in the past decades, e.g. 1992-1993-1994 or 2009-2011-2012, which made the results of crop production critical. Irrigation cannot be the solution for the problem since currently only the 2% of the arable land is irrigated. Temperatures exceeding the multi-year average are characteristic mainly to the July and August in Hungary, which significantly increase the soil surface evaporation, thus further enhance water shortage. In terms of the yield and crop safety of maize, the weather of these two months is crucial, since the extreme high temperature in July decreases the viability of the pollen and the pistil of maize, decreases the extent of fertilization and makes grain-filling tardy. Consequently, yield and crop safety decrease.

Keywords: Abiotic factors, drought, nutrition content, yield.

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Authors: J. Tospornsampan, I. Kita, M. Ishii, Y. Kitamura

Abstract:

In this paper a combination approach of two heuristic-based algorithms: genetic algorithm and tabu search is proposed. It has been developed to obtain the least cost based on the split-pipe design of looped water distribution network. The proposed combination algorithm has been applied to solve the three well-known water distribution networks taken from the literature. The development of the combination of these two heuristic-based algorithms for optimization is aimed at enhancing their strengths and compensating their weaknesses. Tabu search is rather systematic and deterministic that uses adaptive memory in search process, while genetic algorithm is probabilistic and stochastic optimization technique in which the solution space is explored by generating candidate solutions. Split-pipe design may not be realistic in practice but in optimization purpose, optimal solutions are always achieved with split-pipe design. The solutions obtained in this study have proved that the least cost solutions obtained from the split-pipe design are always better than those obtained from the single pipe design. The results obtained from the combination approach show its ability and effectiveness to solve combinatorial optimization problems. The solutions obtained are very satisfactory and high quality in which the solutions of two networks are found to be the lowest-cost solutions yet presented in the literature. The concept of combination approach proposed in this study is expected to contribute some useful benefits in diverse problems.

Keywords: GAs, Heuristics, Looped network, Least-cost design, Pipe network, Optimization, TS

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Authors: Hamed Ahmadi Moghadam, Omolbanin Arasteh Khoshbin

Abstract:

Nowadays, the performance required for concrete structures is more complicated and diversified. Self-compacting concrete is a fluid mixture suitable for placing in structures with congested reinforcement without vibration. Self-compacting concrete development must ensure a good balance between deformability and stability. Also, compatibility is affected by the characteristics of materials and the mix proportions; it becomes necessary to evolve a procedure for mix design of SCC. This paper presents an experimental procedure for the design of self-compacting concrete mixes with different water-cement ratios (w/c) and other constant ratios by local materials. The test results for acceptance characteristics of self-compacting concrete such as slump flow, V-funnel and L-Box are presented. Further, compressive strength, tensile strength and modulus of elasticity of specimens were also determined and results are included here

Keywords: Self-Compacting Concrete, Mix Design, Compressive Strength, Tensile Strength, Modulus of Elasticity

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