Search results for: solution heat treatment

Authors: Damien Gondre, Hatem Ben Maad, Abdelkrim Trabelsi, Frédéric Kuznik, Joseph Virgone

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The use of a radiant cooling solution would enable to lower cooling needs which is of great interest when the demand is initially high (hot climate). But, radiant systems are not naturally compatibles with humid climates since a low-temperature surface leads to condensation risks as soon as the surface temperature is close to or lower than the dew point temperature. A radiant cooling system combined to a dehumidification system would enable to remove humidity for the space, thereby lowering the dew point temperature. The humidity removal needs to be especially effective near the cooled surface. This requirement could be fulfilled by a system using a single desiccant fluid for the removal of both excessive heat and moisture. This task aims at providing an estimation of the specification requirements of such system in terms of cooling power and dehumidification rate required to fulfill comfort issues and to prevent any condensation risk on the cool panel surface. The present paper develops a preliminary study on the specification requirements, performances and behavior of a combined dehumidifier/cooling ceiling panel for different operating conditions. This study has been carried using the TRNSYS software which allows nodal calculations of thermal systems. It consists of the dynamic modeling of heat and vapor balances of a 5m x 3m x 2.7m office space. In a first design estimation, this room is equipped with an ideal heating, cooling, humidification and dehumidification system so that the room temperature is always maintained in between 21^◦C and 25^◦C with a relative humidity in between 40% and 60%. The room is also equipped with a ventilation system that includes a heat recovery heat exchanger and another heat exchanger connected to a heat sink. Main results show that the system should be designed to meet a cooling power of 42W.m⁻² and a desiccant rate of 45 g_H2O.h⁻¹. In a second time, a parametric study of comfort issues and system performances has been achieved on a more realistic system (that includes a chilled ceiling) under different operating conditions. It enables an estimation of an acceptable range of operating conditions. This preliminary study is intended to provide useful information for the system design.

Keywords: dehumidification, nodal calculation, radiant cooling panel, system sizing

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Authors: Heidar Jafarizadeh, Hossein Keshtkar, Ahmad Sohankar

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Heat transfer and turbulent flow structure have been studied in a divergent ribbed duct with a varying duct geometry with Reynolds numbers of 7000 to 90000 using numerical methods. In this study, we confirmed our numerical results of a ribbed duct with an Initial slope of zero to 3 degree by comparing them to experimental data we had and investigated the impact of the ducts divergence on heat transfer and flow pattern in the 2-dimensional flow. Then we investigated the effect of tilting the ribs, on heat transfer and flow behavior. We achieved this by changing the ribs angles from a range of 40 to 75 degrees in a divergent duct and simulated the flow in 3-dimensions. Our results show that with an increase in duct divergence, heat transfer increases linearly and the coefficient of friction increases exponentially. As the results show, a duct with a divergence angle of 1.5 degree presents better thermal performance in comparison with all the angle range’s we studied. Besides, a ribbed duct with 40 degree rib orientation had the best thermal performance considering the simultaneous effects of pressure drop and heat transfer which were imposed on it.

Keywords: divergent ribbed duct, heat transfer, thermal performance, turbulent flow structure

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Authors: Hanan Rizk

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A heat exchanger is a device used to mix liquids having different temperatures. In this case, the temperature control becomes a critical objective. This research work presents the temperature control of the double-pipe heat exchanger (multi-input multi-output (MIMO) system), which is modeled as first-order coupled hyperbolic partial differential equations (PDEs), using conventional and advanced control techniques and develops appropriate robust control strategy to meet stability requirements and performance objectives. We designed a PID controller and H-infinity controller for a heat exchanger (HE) system. Frequency characteristics of sensitivity functions and open-loop and closed-loop time responses are simulated using MATLAB software, and the stability of the system is analyzed using Kalman's test. The simulation results have demonstrated that the H-infinity controller is more efficient than PID in terms of robustness and performance.

Keywords: heat exchanger, multi-input multi-output system, MATLAB simulation, partial differential equations, PID controller, robust control

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Authors: Z. Kolacinski, L. Szymanski. G. Raniszewski, D. Koza, L. Pietrzak

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Magnetic Bio-Nano-Fluid (BNF) can be composed of a buffer fluid such as plasma and magnetic nanoparticles such as iron, nickel, cobalt and their oxides. However iron is one of the best elements for magnetization by electromagnetic radiation. It can be used as a tool for medical diagnosis and treatment. Radio frequency (RF) radiation is able to heat iron nanoparticles due to magnetic hysteresis. Electromagnetic heating of iron nanoparticles and ferro-fluids BNF can be successfully used for non-invasive thermal ablation of cancer cells. Moreover iron atoms can be carried by carbon nanotubes (CNTs) if iron is used as catalyst for CNTs synthesis. Then CNTs became the iron containers and they screen the iron content against oxidation. We will present a method of CNTs addressing to the required cells. For thermal ablation of cancer cells we use radio frequencies for which the interaction with human body should be limited to minimum. Generally, the application of RF energy fields for medical treatment is justified by deep tissue penetration. The highly iron doped CNTs as the carriers creating magnetic fluid will be presented. An excessive catalyst injection method using electrical furnace and microwave plasma reactor will be presented. This way it is possible to grow the Fe filled CNTs on a moving surface in continuous synthesis process. This also allows producing uniform carpet of the Fe filled CNTs carriers. For the experimental work targeted to cell ablation we used RF generator to measure the increase in temperature for some samples like: solution of Fe2O3 in BNF which can be plasma-like buffer, solutions of pure iron of different concentrations in plasma-like buffer and in buffer used for a cell culture, solutions of carbon nanotubes (MWCNTs) of different concentrations in plasma-like buffer and in buffer used for a cell culture. Then the targeted therapies which can be effective if the carriers are able to distinguish the difference between cancerous and healthy cell’s physiology are considered. We have developed an approach based on ligand-receptor or antibody-antigen interactions for the case of colon cancer.

Keywords: cancer treatment, carbon nano tubes, drag delivery, hyperthermia, iron

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Authors: Sen-Yung Lee, Li-Kuo Chou, Chao-Kuang Chen

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In this study, the problem of temperature transient response of a spiral fin, with its end insulated, is analyzed with base end subjected to a variation of fluid temperature. The hybrid method of Laplace transforms/Adomian decomposed method-Padé, is applied to the temperature transient response of the fin, the result of the temperature distribution and the heat flux at the base of the spiral fin are obtained, show a good agreement in the physical phenomenon.

Keywords: Laplace transforms, Adomian decomposed method- Padé, transient response, heat transfer

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Authors: Beghdadi Lotfi, Belkacem Abdellah

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In this work, a numerical method is proposed in order to solve the thermal performance problems of heat transfer of fins surfaces. The bidimensional temperature distribution on the longitudinal section of the fin is calculated by restoring to the finite volumes method. The heat flux dissipated by a generic profile fin is compared with the heat flux removed by the rectangular profile fin with the same length and volume. In this study, it is shown that a finite volume method for quadrilaterals unstructured mesh is developed to predict the two dimensional steady-state solutions of conduction equation, in order to determine the sinusoidal parameter values which optimize the fin effectiveness. In this scheme, based on the integration around the polygonal control volume, the derivatives of conduction equation must be converted into closed line integrals using same formulation of the Stokes theorem. The numerical results show good agreement with analytical results. To demonstrate the accuracy of the method, the absolute and root-mean square errors versus the grid size are examined quantitatively.

Keywords: Stokes theorem, unstructured grid, heat transfer, complex geometry

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Authors: Anuar Ishak

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The characteristics of stagnation point flow of a nanofluid towards a stretching/shrinking sheet are investigated. The governing partial differential equations are transformed into a set of ordinary differential equations, which are then solved numerically using MATLAB routine boundary value problem solver bvp4c. The numerical results show that dual (upper and lower branch) solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the stability of the dual solutions. It is found that the skin friction decreases when the sheet is stretched, but increases when the suction effect is increased. It is also found that increasing the thermophoresis parameter reduces the heat transfer rate at the surface, while increasing the Brownian motion parameter increases the mass transfer rate at the surface.

Keywords: dual solutions, heat transfer, forced convection, nanofluid, stability analysis

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Authors: Ghada Moussa, Mamoud Owais

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Transit Route Network Design Problem (TrNDP) is the most important component in Transit planning, in which the overall cost of the public transportation system highly depends on it. The main purpose of this study is to develop a novel solution methodology for the TrNDP, which goes beyond pervious traditional sophisticated approaches. The novelty of the solution methodology, adopted in this paper, stands on the deterministic operators which are tackled to construct bus routes. The deterministic manner of the TrNDP solution relies on using linear and integer mathematical formulations that can be solved exactly with their standard solvers. The solution methodology has been tested through Mandl’s benchmark network problem. The test results showed that the methodology developed in this research is able to improve the given network solution in terms of number of constructed routes, direct transit service coverage, transfer directness and solution reliability. Although the set of routes resulted from the methodology would stand alone as a final efficient solution for TrNDP, it could be used as an initial solution for meta-heuristic procedures to approach global optimal. Based on the presented methodology, a more robust network optimization tool would be produced for public transportation planning purposes.

Keywords: integer programming, transit route design, transportation, urban planning

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Authors: Damiaa Saad Khudor

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The paper describes an investigation for the thermal design of a fluidized bed cooler and prediction of heat transfer rate among the media categories. It is devoted to the thermal design of such equipment and their application in the industrial fields. It outlines the strategy for the fluidization heat transfer mode and its implementation in industry. The thermal design for fluidized bed cooler is used to furnish a complete design for a fluidized bed cooler of Sodium Bicarbonate. The total thermal load distribution between the air-solid and water-solid along the cooler is calculated according to the thermal equilibrium. The step by step technique was used to accomplish the thermal design of the fluidized bed cooler. It predicts the load, air, solid and water temperature along the trough. The thermal design for fluidized bed cooler revealed to the installation of a heat exchanger consists of (65) horizontal tubes with (33.4) mm diameter and (4) m length inside the bed trough.

Keywords: fluidization, powder technology, thermal design, heat exchangers

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Authors: Jefrey Pilusa, Tumisang Seodigeng

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This research discusses a South African case study for the potential of utilizing refuse-derived fuel (RDF) obtained from non-burn treatment of health care risk waste (HCRW) as potential feedstock for green energy production. This specific waste stream can be destroyed via non-burn treatment technology involving high-speed mechanical shredding followed by steam or chemical injection to disinfect the final product. The RDF obtained from this process is characterised by a low moisture, low ash, and high calorific value which means it can be potentially used as high-value solid fuel. Due to the raw feed of this RDF being classified as hazardous, the final RDF has been reported to be non-infectious and can blend with other combustible wastes such as rubber and plastic for waste to energy applications. This study evaluated non-burn treatment technology as a possible solution for on-site destruction of HCRW in South African private and public health care centres. Waste generation quantities were estimated based on the number of registered patient beds, theoretical bed occupancy. Time and motion study was conducted to evaluate the logistics viability of on-site treatment. Non-burn treatment technology for HCRW is a promising option for South Africa, and successful implementation of this method depends upon the initial capital investment, operational cost and environmental permitting of such technology; there are other influencing factors such as the size of the waste stream, product off-take price as well as product demand.

Keywords: autoclave, disposal, fuel, incineration, medical waste

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Authors: Nkutere Chikezie Kanu, Nnamdi M. Anigbogu, Johnson C. Ezike

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The study was carried out to investigate the performance of Red Sokoto goats fed Municipal Oranic Wastes (MOW) subjected to two methods of in vivo degradation by Torula Yeast and Zymomonas mobilis. Two combination, Torula Yeast + Zymomonas mobilis (main degradation), and Zymomonas mobilis + Torula Yeast (Reciprocal degradation) were used to degrade MOW. Eighteen Red Sokoto goats of both sexes (9 males and 9 females) of ages between 6-8 were used for the study. The goats were randomly assigned into 3 treatments groups A, B and C respectively with 6 goats per treatment. The experiment was laid in a Completely Randomized Design and replicated 3 times. Treatment A groups were fed 30% Undegraded MOW base diet +concentrate mixture, Treatment B groups were fed 30% Main degraded MOW base diet +concentrate mixture, Treatment C groups were fed 30% Reciprocal degraded MOW base diet +concentrate mixture. The result of the daily weight gain was significantly (P<0.05) better than on the other Treatments. There was significant improvement (P<0.05) on the daily feed consumption in Treatment B than on the Treatments A and C. The feed conversion ratio revealed no significant (P>0.05) differences among the treatment groups but much better in the treatment B and C, the cost of feed consumed was much higher (P>0.05) in Treatment B followed by Treatment C, while Treatment A had the lowest. The cost/ kg weight gain that was recorded in Treatment A was better (P<0.05) than the Treatment B, followed by Treatment C, while the cost of production was high (P<0.05) in Treatment B than in other treatments. The gross profit was observed best (P<0.05) on the Treatment B, followed by Treatment C while Treatment A had the lowest. The net profit as noted in this study was much better (P<0.05) in Treatment B, and Treatment C, while the least was observed in Treatment A, where the return on investment was high in Treatments B and C, while Treatment A had the lowest.

Keywords: reciprocal, torula yeast, Zymomonas mobilis, organic waste

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Authors: Mohammadreza Akbari, Sara Akbari, Davood Domiri Ganji, Pooya Solimani, Reza Khalili

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As all experts know most of engineering system behavior in practical are nonlinear process (especially heat, fluid and mass, etc.) and analytical solving (no numeric) these problems are difficult, complex and sometimes impossible like (fluids and gas wave, these problems can't solve with numeric method, because of no have boundary condition) accordingly in this symposium we are going to exposure a innovative approach which we have named it Akbari-Ganji's Method or AGM in engineering, that can solve sets of coupled nonlinear differential equations (ODE, PDE) with high accuracy and simple solution and so this issue will be emerged after comparing the achieved solutions by Numerical method (Runge-Kutte 4th) and so compare to other methods such as HPM, ADM,… and exact solutions. Eventually, AGM method will be proved that could be created huge evolution for researchers, professors and students (engineering and basic science) in whole over the world, because of AGM coding system, so by using this software we can analytically solve all complicated linear and nonlinear differential equations, with help of that there is no difficulty for solving nonlinear differential equations(ODE and PDE). In this paper, we investigate and solve 4 types of the nonlinear differential equation with AGM method : 1-Heat and fluid, 2-Unsteady state of nonlinear partial differential, 3-Coupled nonlinear partial differential in wave equation, and 4-Nonlinear integro-differential equation.

Keywords: new method AGM, sets of coupled nonlinear equations at engineering field, waves equations, integro-differential, fluid and thermal

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Authors: Manatchanok Tantiphiphatthana, Lin Peng, Rujira Jitrwung, Kunio Yoshikawa

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Hydrothermal liquefaction (HTL) is a technique for obtaining clean biofuel from biomass in the presence of heat and pressure in an aqueous medium which leads to a decomposition of this biomass to the formation of various products. A role of operating conditions is essential for the bio-oil and other products’ yield and also quality of the products. The effects of these parameters were investigated in regards to the composition and yield of the products. Chlorellaceae microalgae were tested under different HTL conditions to clarify suitable conditions for extracting bio-oil together with value-added co-products. Firstly, different microalgae loading rates (5-30%) were tested and found that this parameter has not much significant to product yield. Therefore, 10% microalgae loading rate was selected as a proper economical solution for conditioned schedule at 250oC and 30 min-reaction time. Next, a range of temperature (210-290oC) was applied to verify the effects of each parameter by keeping the reaction time constant at 30 min. The results showed no linkage with the increase of the reaction temperature and some reactions occurred that lead to different product yields. Moreover, some nutrients found in the aqueous product are possible to be utilized for nutrient recovery.

Keywords: bio-oil, hydrothermal liquefaction, microalgae, aqueous co-product

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Authors: Mohammad R. Salimpour

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In this study, we investigate experimental laminar forced convective heat transfer specifications of TiO2/water nanofluids through conduits with different cross sections. Ee check the effects of different parameters such as cross sectional shape, Reynolds number and concentration of nanoparticles in stable suspension on increasing convective heat transfer by designing and assembling of an experimental apparatus. The results demonstrate adding a little amount of nanoparticles to the base fluid, improves heat transfer behavior in conduits. Moreover, conduit with circular cross-section has better performance compared to the square and triangular cross sections. However, conduits with square and triangular cross sections have more relative heat transfer enhancement than conduit with circular cross section.

Keywords: nanofluid, cross-sectional shape, TiO2, convection

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Authors: Rebhi A. Damseh, H. M. Duwairi, Benbella A. Shannak

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This work deals with heat and mass transfer by steady laminar boundary layer flow of a Newtonian, viscous fluid over a vertical flat plate with variable surface heat flux embedded in a fluid saturated porous medium in the presence of thermophoresis particle deposition effect. The governing partial differential equations are transformed into no-similar form by using special transformation and solved numerically by using an implicit finite difference method. Many results are obtained and a representative set is displaced graphically to illustrate the influence of the various physical parameters on the wall thermophoresis deposition velocity and concentration profiles. It is found that the increasing of thermophoresis constant or temperature differences enhances heat transfer rates from vertical surfaces and increase wall thermophoresis velocities; this is due to favourable temperature gradients or buoyancy forces. It is also found that the effect of thermophoresis phenomena is more pronounced near pure natural convection heat transfer limit; because this phenomenon is directly a temperature gradient or buoyancy forces dependent. Comparisons with previously published work in the limits are performed and the results are found to be in excellent agreement.

Keywords: thermophoresis, porous medium, variable surface heat flux, heat transfer

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Authors: Opata Obinna Johnpaul

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Wastewater is one of the day-to–day concerns of humans and the environment, in general, due to its importance to the environment. This is because of the presence of various contaminants that are involved in waste water. Wastewater treatment can be defined as the proportion of wastewater that is treated, in order to reduce pollutants before being discharged to the environment, by the level of treatment. This work discusses wastewater treatment, its contaminants, as well as the technologies, involved.The major focus is to analyze Okomu Oil Palm Company Plc, their effluent treatment facility. Okomu Oil Palm Company is based in Nigeria, which is one of the developing countries of the world. Okomu Oil Palm Company uses aquatic treatment technology for their effluent treatment and applies the physio-chemical level of advanced chemical treatment of wastewater treatment process. This work will discuss the outcome of the laboratory sample taken on the 30th January, 2015 and analyzed between 30th January- 4th February 2015.

Keywords: wastewater treatment, contaminants, physio-chemical process, Okomu oil palm

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Authors: Ziya Uddin

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This paper deals with the theoretical and numerical investigation of magneto-hydrodynamic boundary layer flow of a nano fluid past a wedge shaped wick in heat pipe used for the cooling of electronic components and different type of machines. To incorporate the effect of nanoparticle diameter, concentration of nanoparticles in the pure fluid, nano thermal layer formed around the nanoparticle and Brownian motion of nano particles etc., appropriate models are used for the effective thermal and physical properties of nano fluids. To model the rotation of nano particles inside the base fluid, microfluidics theory is used. In this investigation ethylene glycol (EG) based nanofluids, are taken into account. The non-linear equations governing the flow and heat transfer are solved by using a very effective particle swarm optimization technique along with Runge-Kutta method. The values of heat transfer coefficient are found for different parameters involved in the formulation viz. nanoparticle concentration, nanoparticle size, magnetic field and wedge angle etc. It is found that the wedge angle, presence of magnetic field, nanoparticle size and nanoparticle concentration etc. have prominent effects on fluid flow and heat transfer characteristics for the considered configuration.

Keywords: nanofluids, wedge shaped wick, heat pipe, numerical modeling, particle swarm optimization, nanofluid applications, Heat transfer

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Authors: Mazarine Roquet, Pierre Dewallef

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The building sector, both residential and tertiary, accounts for a significant share of greenhouse gas emissions. In Belgium, partly due to poor insulation of the building stock, but certainly because of the massive use of fossil fuels for heating buildings, this share reaches almost 30%. To reduce carbon emissions from urban building heating, district heating networks emerge as a promising solution as they offer various assets such as improving the load factor, integrating combined heat and power systems, and enabling energy source diversification, including renewable sources and waste heat recovery. However, mainly for sake of simple operation, most existing district heating networks still operate at high or medium temperatures ranging between 120°C and 60°C (the socalled second and third-generations district heating networks). Although these district heating networks offer energy savings in comparison with individual boilers, such temperature levels generally require the use of fossil fuels (mainly natural gas) with combined heat and power. The fourth-generation district heating networks improve the transport and energy conversion efficiency by decreasing the operating temperature between 50°C and 30°C. Yet, to decarbonise the building heating one must increase the waste heat recovery and use mainly wind, solar or geothermal sources for the remaining heat supply. Fifth-generation networks operating between 35°C and 15°C offer the possibility to decrease even more the transport losses, to increase the share of waste heat recovery and to use electricity from renewable resources through the use of heat pumps to generate low temperature heat. The main objective of this contribution is to exhibit on a real-life test case the benefits of replacing an existing third-generation network by a fifth-generation one and to decarbonise the heat supply of the building stock. The second objective of the study is to highlight the difficulties resulting from the use of a fifth-generation, low-temperature, district heating network. To do so, a simulation model of the district heating network including its regulation is implemented in the modelling language Modelica. This model is applied to the test case of the heating network on the University of Liège's Sart Tilman campus, consisting of around sixty buildings. This model is validated with monitoring data and then adapted for low-temperature networks. A comparison of primary energy consumptions as well as CO2 emissions is done between the two cases to underline the benefits in term of energy independency and GHG emissions. To highlight the complexity of operating a lowtemperature network, the difficulty of adapting the mass flow rate to the heat demand is considered. This shows the difficult balance between the thermal comfort and the electrical consumption of the circulation pumps. Several control strategies are considered and compared to the global energy savings. The developed model can be used to assess the potential for energy and CO2 emissions savings retrofitting an existing network or when designing a new one.

Keywords: building simulation, fifth-generation district heating network, low-temperature district heating network, urban building heating

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Authors: Larbi Hammadi, Abdellatif El Bari Tidjani

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In order to reduce the flow of pollutants in the wastewater of the urban agglomerations of the city of Oran, a preliminary study was carried out at the El-Karma wastewater treatment plant. The primary objective of this study was to estimate the overall physicochemical pollution in the effluents of the El-Karma sewage treatment plant wastewater. It was found that the effluent of El-Karma wastewater treatment plant contains a significant amount of insoluble. Total suspended soli TSS concentrations ranged from 112 to 475 mg/l, with an average of 220.5 mg/l. The chemical oxygen demand (COD) and biochemical oxygen demand (BOD₅) values remain within the reference range for domestic wastewater with an average value of COD < 125 and BOD₅ < 25. The COD/BOD₅ ratio of raw water entering the treatment plant is less than 2. This ratio would predict that the raw sewage from the El-Karma treatment plant is polluted by inorganic pollution strong enough.

Keywords: El-Karma wastewater, TSS concentrations, COD and BOD5, COD/BOD5 ratio, treatment

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Authors: R. Benelmir, M. El Kadri, A. Donnot, D. Descieux

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HVAC represents a significant part of energy needs in buildings. Integrating renewable energy in cooling processes contributes to reducing primary energy consumption. Sorption refrigeration allows cold production through the use of solar/biomass/geothermal energy or even valuation of waste heat. This work presents an analysis of an experimental bench incorporating an adsorption chiller driven by hybrid energy resources associating solar thermal collectors with a cogeneration gas engine and a geothermal heat pump.

Keywords: solar cooling, cogeneration, geothermal heat pump, hybrid energy resources

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Authors: Emine Aydin, Duygu Gocmen

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Pumpkin flour (PF) has a long shelf life and can be used as a nutritive, functional (antioxidant properties, phenolic contents, etc.) and coloring agent in many food items, especially in bakery products, sausages, instant noodles, pasta and flour mixes. Pre-treatment before drying is one of the most important factors affecting the quality of a final powdered product. Pretreatment, such as soaking in a bisulfite solution, provides that total carotenoids in raw materials rich in carotenoids, especially pumpkins, are retained in the dried product. This is due to the beneficial effect of antioxidant additives in the protection of carotenoids in the dehydrated plant foods. The oxygen present in the medium is removed by the radical SO₂, and thus the carotene degradation caused by the molecular oxygen is inhibited by the presence of SO₂. In this study, pumpkin flours (PFs) produced by two different applications (with or without metabisulfite pre-treatment) and then dried in a freeze dryer. The phenolic contents and antioxidant activities of pumpkin flour were determined. In addition to this, the compound of bioavailable phenolic substances which is obtained by PF has also been investigated using in vitro methods. As a result of researches made in recent years, it has been determined that all nutrients taken with foodstuffs are not bioavailable. Bioavailability changes depending on physical properties, chemical compounds, and capacities of individual digestion of foods. Therefore in this study; bioaccessible phenolics and phenolic bioaccessibility were also determined. The phenolics of the samples with metabisulfite application were higher than those of the samples without metabisulfite pre-treatment. Soaking in metabisulfite solution might have a protective effect for phenolic compounds. Phenolics bioaccessibility of pumpkin flours was investigated in order to assess pumpkin flour as sources of accessible phenolics. The higher bioaccessible phenolics (384.19 mg of GAE 100g⁻¹ DW) and phenolic bioaccessibility values (33.65 mL 100 mL⁻¹) were observed in the pumpkin flour with metabisulfite pre-treatment. Metabisulfite application caused an increase in bioaccessible phenolics of pumpkin flour. According to all assay (ABTS, CUPRAC, DPPH, and FRAP) results, both free and bound phenolics of pumpkin flour with metabisulfite pre-treatment had higher antioxidant activity than those of the sample without metabisulfite pre-treatment. The samples subjected to MS pre-treatment exhibited higher antioxidant activities than those of the samples without MS pre-treatment, this possibly due to higher phenolic contents of the samples with metabisulfite applications. As a result, metabisulfite application caused an increase in phenolic contents, bioaccessible phenolics, phenolic bioaccessibility and antioxidant activities of pumpkin flour. It can be said that pumpkin flour can be used as an alternative functional and nutritional ingredient in bakery products, dairy products (yoghurt, ice-cream), soups, sauces, infant formulae, confectionery, etc.

Keywords: pumpkin flour, bioaccessible phenolics, phenolic bioaccessibility, antioxidant activity

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Authors: Fatima Huda Hallak

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The current study aimed to evaluate the activity of bacterial insecticide Vertinic against the second star larvae of Trogoderma granarium (Everts) by four treatments: A, B, C, D, at seven concentrations: 0.001, 0.01, 0.1,1,10,100,1000 PPM. The mortality rate of larvae was 100% at concentrations 10 and 100 in treatments A and B after 24 hours and after 48 hours in treatment D at 1 PPM. The efficiency of treatment A was greater as compared to treatment B at all concentrations and all exposure times. The efficiency of treatment D was greater as compared to treatment C; for example, at 0.001, 0.01, 0.1, 1 PPM, after 120 hours, the Mortality rate of larve was 6.76, 13.33, 43.33, 100% in treatment D, which it was 0.00, 0.00, 23.33, 96.67%, respectively in the treatment C.

Keywords: bacterial insecticide, trogoderma granarium (everts), fourth star larvae, vertimic

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Authors: Pradeep G. Siddheshwar, K. M. Lakshmi

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The present study deals with weakly non-linear stability analysis of Rayleigh-Benard-Brinkman convection in nanoliquid-saturated porous enclosures. The modified-Buongiorno-Brinkman model (MBBM) is used for the conservation of linear momentum in a nanoliquid-saturated-porous medium under the assumption of Boussinesq approximation. Thermal equilibrium is imposed between the base liquid and the nanoparticles. The thermophysical properties of nanoliquid are modeled using phenomenological laws and mixture theory. The fifth-order Lorenz model is derived for the problem and is then reduced to the first-order Ginzburg-Landau equation (GLE) using the multi-scale method. The analytical solution of the GLE for the amplitude is then used to quantify the heat transport in closed form, in terms of the Nusselt number. It is found that addition of dilute concentration of nanoparticles significantly enhances the heat transport and the dominant reason for the same is the high thermal conductivity of the nanoliquid in comparison to that of the base liquid. This aspect of nanoliquids helps in speedy removal of heat. The porous medium serves the purpose of retainment of energy in the system due to its low thermal conductivity. The present model helps in making a unified study for obtaining the results for base liquid, nanoliquid, base liquid-saturated porous medium and nanoliquid-saturated porous medium. Three different types of enclosures are considered for the study by taking different values of aspect ratio, and it is observed that heat transport in tall porous enclosure is maximum while that of shallow is the least. Detailed discussion is also made on estimating heat transport for different volume fractions of nanoparticles. Results of single-phase model are shown to be a limiting case of the present study. The study is made for three boundary combinations, viz., free-free, rigid-rigid and rigid-free.

Keywords: Boungiorno model, Ginzburg-Landau equation, Lorenz equations, porous medium

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Authors: Natalia Muratova, Dmitry Klimov, Rafail Isemin, Sergey Kuzmin, Aleksandr Mikhalev, Oleg Milovanov

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We investigated the processing of poultry litter into biochar using dry torrefaction methods (DT) in a fixed and fluidized bed of quartz sand blown with nitrogen, as well as wet torrefaction (WT) in a fluidized bed in a medium of water steam at a temperature of 300 °C. Torrefaction technology affects the duration of the heat treatment process and the characteristics of the biochar: the process of separating CO₂, CO, H₂ and CH₄ from a portion of fresh poultry litter during torrefaction in a fixed bed is completed after 2400 seconds, but in a fluidized bed — after 480 seconds. During WT in a fluidized bed of quartz sand, this process ends in 840 seconds after loading a portion of fresh litter, but in a fluidized bed of litter particles previously subjected to torrefaction, the process ends in 350 - 450 seconds. In terms of the ratio between (H/C) and (O/C), the litter obtained after DT and WT treatment corresponds to lignite. WT in a fluidized bed allows one to obtain biochar, in which the specific pore area is two times larger than the specific pore area of biochar obtained after DT in a fluidized bed. Biochar, obtained as a result of the poultry litter treatment in a fluidized bed using DT or WT method, is recommended to be used not only as a biofuel but also as an adsorbent or the soil fertilizer.

Keywords: biochar, poultry litter, dry and wet torrefaction, fixed bed, fluidized bed

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Authors: Ademuyiwa Agbonyin, Stamatis Zoras, Mohammad Zandi

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This paper investigates the extent to which building energy modelling can be informed based on preliminary information provided by infrared thermography using a thermal imaging camera in a walkthrough audit. The case-study building is the Sheffield Cathedral, built in the early 1400s. Based on an informative qualitative report generated from the thermal images taken at the site, the regions showing significant heat loss are input into a computer model of the cathedral within the integrated environmental solution (IES) virtual environment software which performs an energy simulation to determine quantitative heat losses through the building envelope. Building data such as material thermal properties and building plans are provided by the architects, Thomas Ford and Partners Ltd. The results of the modelling revealed the portions of the building with the highest heat loss and these aligned with those suggested by the thermal camera. Retrofit options for the building are also considered, however, may not see implementation due to a desire to conserve the architectural heritage of the building. Results show that thermal imaging in a walk-through audit serves as a useful guide for the energy modelling process. Hand calculations were also performed to serve as a 'control' to estimate losses, providing a second set of data points of comparison.

Keywords: historic buildings, energy retrofit, thermal comfort, software modelling, energy modelling

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Authors: Ilma Robo, Saimir Heta, Emela Dalloshi, Nevila Alliu, Vera Ostreni

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The dental whitening process, beyond the fact that it is a mini-invasive dental treatment, has effects on the dental structure, or on the pulp of the tooth, where it is applied. The electronic search was performed using keywords to find articles published within the last 10 years about side effects, assessed as such, of minimally invasive dental bleaching treatment. Methodology: In selected articles, the other aim of the study was to evaluate the side effects of bleaching based on the percentage and type of solution used, where the latter was evaluated on the basic solution used for bleaching. Results: The side effects of bleaching are evaluated in selected articles depending on the method of bleaching application, which means it is carried out with recommended solutions, or with mixtures of alternative solutions or substances based on Internet information. Short conclusion: The dental bleaching process has side effects which have not yet been definitively evaluated, experimentally in large samples of individuals or animals (mice or cattle) to arrive at accurate numerical conclusions. The trend of publications about this topic is increasing in recent years, as long as the trend for aesthetic facial treatments, including dental ones, is increasing.

Keywords: teeth whitening, side effects, permanent teeth, formed dental apex

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Authors: Md. Asif Ullah, M. A. R. Sarkar

Abstract:

This paper illustrates 2-D and 3-D simulations of sub-channels of a Pressurized Water Reactor (PWR) having hexagonal array of fuel rods. At a steady state, the temperature of outer surface of the cladding of fuel rod is kept about 1200°C. The temperature of this isothermal surface is taken as boundary condition for simulation. Water with temperature of 290°C is given as a coolant inlet to the primary water circuit which is pressurized upto 157 bar. Turbulent flow of pressurized water is used for heat removal. In 2-D model, temperature, velocity, pressure and Nusselt number distributions are simulated in a vertical sectional plane through the sub-channels of a hexagonal fuel rod assembly. Temperature, Nusselt number and Y-component of convective heat flux along a line in this plane near the end of fuel rods are plotted for different Reynold’s number. A comparison between X-component and Y-component of convective heat flux in this vertical plane is analyzed. Hexagonal fuel rod assembly has three types of sub-channels according to geometrical shape whose boundary conditions are different too. In 3-D model, temperature, velocity, pressure, Nusselt number, total heat flux magnitude distributions for all the three sub-channels are studied for a suitable Reynold’s number. A horizontal sectional plane is taken from each of the three sub-channels to study temperature, velocity, pressure, Nusselt number and convective heat flux distribution in it. Greater values of temperature, Nusselt number and Y-component of convective heat flux are found for greater Reynold’s number. X-component of convective heat flux is found to be non-zero near the bottom of fuel rod and zero near the end of fuel rod. This indicates that the convective heat transfer occurs totally along the direction of flow near the outlet. As, length to radius ratio of sub-channels is very high, simulation for a short length of the sub-channels are done for graphical interface advantage. For the simulations, Turbulent Flow (K-Є ) module and Heat Transfer in Fluids (ht) module of COMSOL MULTIPHYSICS 5.0 are used.

Keywords: sub-channels, Reynold’s number, Nusselt number, convective heat transfer

Procedia PDF Downloads 357

Authors: Zoran Herceg, Višnja Stulić, Tomislava Vukušić, Anet Režek Jambrak

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High voltage electrical discharge is a new technology used for inactivation of pathogen microorganisms. Pathogen yeasts can cause diseases in humans if they are ingested. Nowadays new technologies have become the focus of researching all over the world. Rhodotorula is known as yeast that can cause diseases in humans. The aim of this study was to examine whether the high voltage electrical discharge treatment generated in gas phase has an influence on yeast reduction and recovery of Rhodotorula spp 74 in pure culture. Rhodotorula spp. 74 was treated in 200 mL of model solution. Treatment time (5 and 10 min), frequency (60 and 90 Hz) and injected gas (air or argon 99,99%) were changed. Titanium high voltage needle was used as high voltage electrode (positive polarity) through which air or argon was injected at the gas flow of 0.6 L/min. Experimental design and statistical analyses were obtained by Statgraphics Centurion software (StatPoint Technologies, Inc., VA, USA). The best inactivation rate 1.7 log10 reduction was observed after the 10 min of treatment, frequency of 90 Hz and injected air. Also with a longer treatment time inactivation rate was higher. After the 24 h recovery of treated samples was observed. Therefore the further optimization of method is needed to understand the mechanism of yeasts inactivation and cells recovery after the treatment. Acknowledgements: 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: rhodotorula spp. 74, electrical discharge plasma, inactivation, stress response

Procedia PDF Downloads 233

Authors: Mohammad Taghi Karbalaei Aghamolki, Mohd Khanif Yusop, Fateh Chand Oad, Hamed Zakikhani, Hawa Zee Jaafar, Sharifh Kharidah, Mohamed Hanafi Musa, Shahram Soltani

Abstract:

The high temperatures during sensitive growth phases are changing rice morphology as well as influencing yield. In the glass house study, the treatments were: growing conditions [normal growing (32oC+2) and heat stress (38oC+2) day time and 22oC+2 night time], growth stages (booting, flowering and ripening) and four cultivars (Hovaze, Hashemi, Fajr, as exotic and MR219 as indigenous). The heat chamber was prepared covered with plastic, and automatic heater was adjusted at 38oC+2 (day) and 22oC+2 (night) for two weeks in every growth stages. Rice morphological and yield under the influence of heat stress during various growth stages showed taller plants in Hashsemi due to its tall character. The total tillers per hill were significantly higher in Fajr receiving heat stress during booting stage. In all growing conditions and growth stages, Hashemi recorded higher panicle exertion and flag leaf length. The flag leaf width in all situations was found higher in Hovaze. The total tillers per hill were more in Fajr, although heat stress was imposed during booting and flowering stages. The indigenous MR219 in all situations of growing conditions, growth stages recorded higher grain yield. However, its grain yield slightly decreased when heat stress was imposed during booting and flowering. Similar results were found in all other exotic cultivars recording to lower grain yield in the heat stress condition during booting and flowering. However, plants had no effect on heat stress during ripening stage.

Keywords: rice, growth, heat, temperature, stress, morphology, yield

Procedia PDF Downloads 269

Authors: Muzna Tariq, Ihtzaz Qamar

Abstract:

In most engineering cases, the working temperatures inside a combustion chamber are high enough that they lie beyond the operational range of thermocouples. Furthermore, design and manufacturing limitations restrict the use of internal thermocouples in many applications. Heat transfer inside a combustion chamber is caused due to interaction of the post-combustion hot fluid with the chamber wall. Heat transfer that involves an interaction between the fluid and solid is categorized as Conjugate Heat Transfer (CHT). Therefore, to satisfy the needs of CHT, CHT Analysis is performed by using ANSYS CFD tool to estimate theoretically precise thermocouple positions at the combustion chamber wall where excessive temperatures (beyond thermocouple range) can be avoided. In accordance with these Computational Fluid Dynamics (CFD) results, a combustion chamber is designed, and a prototype is manufactured with multiple thermocouple ports positioned at the specified distances so that the temperature of hot gases can be measured on the chamber wall where the temperatures do not exceed the thermocouple working range.

Keywords: computational fluid dynamics, conduction, conjugate heat transfer, convection, fluid flow, thermocouples

Procedia PDF Downloads 144