S. A. Gandjalikhan Nassab; M. Moein Addini
Abstract
In the present paper, the use of radiating gas instead of air inside the cavity of compound parabolic collectors (CPSs) is suggested and verified by numerical analysis. The collector under study has a simple cone shape with flat absorber which is filled with a participating gas such as carbon dioxide ...
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In the present paper, the use of radiating gas instead of air inside the cavity of compound parabolic collectors (CPSs) is suggested and verified by numerical analysis. The collector under study has a simple cone shape with flat absorber which is filled with a participating gas such as carbon dioxide instead of air for the purpose of increasing the thermal performance. In numerical simulation, the continuity, momentum and energy equations for the steady natural convection laminar gas flow in the CPC’s cavity and the conduction equation for glass cover and absorber plate were solved by the finite element method (FEM) using the COMSOL multi-physics. Because of the radiative term in the gas energy equation, the intensity of radiation in participating gas flow should be computed. Toward this end, the radiative transfer equation (RTE) was solved by the discrete ordinate method (DOM), considering both diffuse and collimated radiations. The approximation was employed in calculation of the diffuse part of radiation. It was observed that the gas radiation causes high temperature with more uniform distribution inside the cavity of collector. Also, numerical results reveal more than 3% increase in the rate of heat transfer from absorber surface into working fluid and hence a desired performance for the collector because of the gas radiation effect. Comparison between the present numerical results with theoretical and experimental data reported in the literature showed good consistency.
O. O. Obiukwu; M. N. Uchechukwu; T. Uchechukwu
Abstract
Biodegradable composites (SCB-PES) and a control sample were developed from polyester resin (PES) matrix and sugar cane bagasse (SCB) fibre at different matrix- fibre compositions using the compression technique. The effects of fibre content (9–54 wt%) and fibre treatment on thermal and dynamic ...
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Biodegradable composites (SCB-PES) and a control sample were developed from polyester resin (PES) matrix and sugar cane bagasse (SCB) fibre at different matrix- fibre compositions using the compression technique. The effects of fibre content (9–54 wt%) and fibre treatment on thermal and dynamic mechanical properties of polyester / sugar cane bagasse fibre biocomposites were evaluated via thermogravimetric analysis (TGA) and DMA (Model: DMA 242 E Artemis) storage modulus (E1), loss modulus (E11), change in length of modulus (∆l), tan delta (E11/ E1) and glass transition temperature (Tg). The results showed that while the weight of the pure PES matrix showed a near complete disappearance between 400 –500 0C, the 9 % FW SCB-PES composite lost nearly 50% of its weight, in the same temperature region. The results which show that SCB-PES composites demonstrated acceptable thermal and abrasion properties portrays the effectiveness of SCB as reinforcement for PES matrix and the potential of the eco-friendly composites in the fabrication of utility materials for sustainable development. The weight loss (wt%) by the composites after 6 months soil burying test ranged from 22.24 -85.34 %.
Energy
N. Momen; H. Pahlavanzadeh
Abstract
Nowadays, due to environmental concerns and the reduction in fossil fuel resources, biodiesel is being considered as a renewable alternative or supplement to fossil diesel. In this research, the transesterification method was used to produce biodiesel from low-cost and non-edible linseed oil in the presence ...
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Nowadays, due to environmental concerns and the reduction in fossil fuel resources, biodiesel is being considered as a renewable alternative or supplement to fossil diesel. In this research, the transesterification method was used to produce biodiesel from low-cost and non-edible linseed oil in the presence of commercial calcium oxide as the catalyst. In addition, the time-consuming and costly calcination step was omitted and a deep eutectic co-solvent of choline chloride/glycerol (2:1) was used to activate the catalyst. The catalyst characterization was studied using X-ray diffraction(XRD) and Fourier transform infrared (FTIR). To ensure the formation of fatty acid methyl esters (FAME), the purity of FAME in the produced biodiesel was calculated using gas chromatography method. Then, the effect of two reaction parameters of the catalyst and the DES concentration on the FAME purity was investigated at a constant temperature of 65 °C, stirring speed of 500 rpm, reaction time of 180 minutes and the methanol to oil molar ratio of 9.5:1. Finally, the optimal catalyst and the DES concentration were obtained as 10% and 14%, respectively. The effect of temperature and time on the FAME purity was investigated and a kinetic study of the reaction suggested a pseudo-first-order reaction with a rate constant of 0.0311 at 65 °C and activation energy of 22.45 kJ/mol.
Energy
H. Farzan; M. Mahmoudi; E. Hasan Zaim
Abstract
Solar air heaters (SAHs) have an inherent drawback: the conventional mechanism is low inside these collectors’ types. Use of perforations is a simple technique to improve convection, and this investigation experimentally assesses a novel design SAH utilizing three inclined perforated absorber plates. ...
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Solar air heaters (SAHs) have an inherent drawback: the conventional mechanism is low inside these collectors’ types. Use of perforations is a simple technique to improve convection, and this investigation experimentally assesses a novel design SAH utilizing three inclined perforated absorber plates. Two scenarios are considered to assess the dynamics and efficiency of this perforated SAH, including mair = 0.012 kg/s and 0.024 kg/s. Numerous sensors monitored the dynamics of the perforated SAH and ambient factors for 12 hours in October 2022. The experimental outcomes illustrate that the perforation method remarkably enhances the thermal efficiency of the perforated SAH compared with standard smooth SAHs. The daily thermal efficiency of the perforated SAH reaches 73.30% and 82.65%, while the outlet air temperature experiences peak values of 39 oC and 42 oC at noon and keeps within 90% of its maximum value for 2 hours for the scenarios considered. Improving the convection mechanism causes the flowing air to extract the absorber’s thermal energy more effectively. Hence the SAH can produce an airstream near its maximum temperature for an extended duration. In conclusion, the perforation method is a robust, simple method to boost the thermal efficiency of SAHs.
Y. Setiawan; A. Taufik Rizaludin; M. Nur Aini; S. Saepuloh
Abstract
The Polyester synthetic fiber (PSF) industry has recycled Polyethylene Terephthalate (PET) bottle into raw material and converted them into economically valuable textile materials. This study was aimed to provide an overview of wastewater treatment from PSF industry in minimizing its impact on the environment. ...
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The Polyester synthetic fiber (PSF) industry has recycled Polyethylene Terephthalate (PET) bottle into raw material and converted them into economically valuable textile materials. This study was aimed to provide an overview of wastewater treatment from PSF industry in minimizing its impact on the environment. The study of wastewater treatment from PSF industry has been carried out in chemical-physical treatment. The Jar Test experiment has been conducted with coagulant and flocculant addition into 1,000 mL of wastewater inside a 1 L beaker glass. Wastewater was treated with 3 coagulants and flocculant doses variation with range of PAC 175-225 mg/L and PE 0.25 mg / L. The results showed that the dose utilization of 200 mg/L of 5% Poly Aluminum Chloride (PAC) coagulant solution and 0.25 mg/L dose of 0.02% Poly Electrolyte (PE) flocculant solution could produce a treated wastewater that has complied with the effluent quality standards. The application of this optimum dose can reduce wastewater pollutants subtances of PSF industry which can minimize its impact on the environment.
A. Abderrahim; M. M. Boudia; N. Ghellai; Y. Menni; H. Ameur
Abstract
This paper aims to determine the wind potential in two regions of Algeria according to months, seasons, and entire years. An attempt is made to participate to the update of the wind map in this country, by using the collected hourly data during a period of more than thirty years. The Weibull function ...
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This paper aims to determine the wind potential in two regions of Algeria according to months, seasons, and entire years. An attempt is made to participate to the update of the wind map in this country, by using the collected hourly data during a period of more than thirty years. The Weibull function is employed to perform the wind data analysis. Two regions are considered: Ilizi and Oran, which are located in the southeast and northwest of Algeria, respectively. The values of the Weibull parameters, average power density, and mean velocity are employed to achieve the statistical analysis. At the height of 10 m from the ground, the obtained results revealed that the highest annual average rate of 6.5 m/s occurred at the city of 'Illizi'. It was also found that the city of 'Es-senia' has a middle potential of wind with an annual mean velocity of 3.5m/s. Furthermore, it was observed that the spring season is the most windy season for both regions.
Energy
N. Hedayati Goodarzi; M. Rahimi-Esbo
Abstract
Steam reformers are typically utilized in hydrogen production industry, demanding pressure vessels within methanol reformer systems operating at temperatures between 250-350°C to ensure cost-effectiveness. This characteristic makes them a superior choice for fuel cell systems. However, challenges ...
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Steam reformers are typically utilized in hydrogen production industry, demanding pressure vessels within methanol reformer systems operating at temperatures between 250-350°C to ensure cost-effectiveness. This characteristic makes them a superior choice for fuel cell systems. However, challenges arise in enhancing hydrogen gas production efficiency while minimizing carbon monoxide emissions. Computational Fluid Dynamics (CFD) has proven effective in addressing these challenges by simulating fluid behavior. This study delves into product production, reactant consumption using CFD, and investigates changes in physical parameters of methanol reformers to optimize their performance. The research involves 140 numerical simulations that examine the relationship between feeds (steam-to-carbon) and various temperatures, aiming to understand the concurrent effect of physical parameters. The results demonstrate that increasing temperature has a more significant impact on hydrogen production compared to increasing the feed ratio. This effect is particularly notable at lower fuel ratios. For example, at a feed ratio of 1, a temperature increase of 11.4°C leads to a substantial 5.4% rise in hydrogen production. However, at a higher feed ratio (1.98), the increase in hydrogen production is only 1.9% with the same temperature increase.
K. M. Akkoli; S. A. Goudadi; M. M. Shivashimpi; S. N. Topannavar
Abstract
An analysis of the experimental characterization of the three agricultural residues redgram stalk, soyabean stalk, and chilli stalk (biomass) was carried out and the higher heating values (HHV) were determined using the available correlations from the literature. The selected agricultural residues proximate ...
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An analysis of the experimental characterization of the three agricultural residues redgram stalk, soyabean stalk, and chilli stalk (biomass) was carried out and the higher heating values (HHV) were determined using the available correlations from the literature. The selected agricultural residues proximate analysis results show moisture about 4.2 to 7.4%, the volatile matter about 79.3 to 85.8%, fixed carbon about 4 to 8.94%, and ash about 2.5 to 5.5%. The ultimate analysis results present elemental compositions such as carbon about 46 to 49%, hydrogen about 5%, oxygen about 30%, and the nitrogen about 3.1 to 3.7% with very low sulfur content. The HHV of agricultural residues varies from 14MJ kg-1 to 19MJ kg-1. The design of the downdraft gasifier to accommodate agricultural residues was carried out taking into account the characteristics of the agricultural residues and the specifications of the internal combustion (IC) engine. The characteristics of the agricultural residues depict that the three agricultural residues are suitable for gasification and can be used in a single gasifier.
N. Norouzi; M. Fani
Abstract
As COVID-19 has propagated well-known, governments have taken nationwide moderation to restrain it, from regulations to moves toward off the economization as a whole. Know-how its outcome is imperative to help larger policies for nations that are not but preponderant or in the outcome of a succeeding ...
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As COVID-19 has propagated well-known, governments have taken nationwide moderation to restrain it, from regulations to moves toward off the economization as a whole. Know-how its outcome is imperative to help larger policies for nations that are not but preponderant or in the outcome of a succeeding epidemic. Here we demonstrated that the aggregated conquest in electricity decay in the five-month sequential homestay management became among 3% and 12% in most affected European and Asia countries; besides, Florida, which has not proven any continuous variation. For the reason that Italy, France, Spain, China, and India got greater fundamental damage through the limit of July, especially Britain and Germany are under the baseline. We also showed that the connection between severity and the curtailment of covid-19 based electricity decay is not linear. Those findings showed the extremity of the disaster in different nations and could further look at the upcoming, similar global crisis.
Environment
A. Yousefi Kebriya; M. Nadi
Abstract
The Air Quality Index is a numerical tool used to quantify air pollution levels and classify pollution severity. It plays a vital role in ensuring healthcare system stability by understanding air pollution's dynamic behavior and shifts in pollution intensity. To analyze the probabilistic transition between ...
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The Air Quality Index is a numerical tool used to quantify air pollution levels and classify pollution severity. It plays a vital role in ensuring healthcare system stability by understanding air pollution's dynamic behavior and shifts in pollution intensity. To analyze the probabilistic transition between pollution severity levels, a Markov Chain model was utilized. This study examined six air pollution states (Clean, Healthy, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, Hazardous) across 12 stations in Tehran's northern, southern, eastern, western, and central regions from 2018 to 2022. Results revealed that the western and southern areas exhibited the highest pollution levels, with over 44% and 34% of instances corresponding to unhealthy indices, respectively. In contrast, northern Tehran consistently maintained cleaner air quality. Probability transition matrices highlighted the greatest stability continuity in healthy air quality across all regions. Transitioning between clean/healthy air to very unhealthy/hazardous air was minimal, with hazardous air quality almost absent in most stations, except for the west and south (25% stability). The probability of continued unhealthy air quality in these areas reached 60%, indicating heightened pollution. The findings of transition probability matrices indicated that the western and southern regions had the highest likelihood of sustained pollution, while the northern region consistently maintained cleaner air. The probability of continuous clean air in the west was below 30%, while transitioning from very unhealthy/hazardous air to unhealthy air reached 50%. Conversely, the northern Tehran region exhibited over 40% stability for unhealthy air quality and over 50% for clean and healthy air.
Energy
A. H. Shiravi; M. Firoozzadeh
Abstract
Nowadays, the world is moving toward using renewable and sustainable energy sources, as much as possible. Photovoltaic (PV) technology is one of the most popular alternatives. PVs are widely used to supply electricity for pumping systems to irrigate the farmlands. It has been proved by many scholars ...
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Nowadays, the world is moving toward using renewable and sustainable energy sources, as much as possible. Photovoltaic (PV) technology is one of the most popular alternatives. PVs are widely used to supply electricity for pumping systems to irrigate the farmlands. It has been proved by many scholars that PV cell temperature is a crucial factor in cell’s efficiency. In this study, a novel arrangement of a PV/pumping system has been considered, in order to enhance the pumping performance. To make it feasible, a small part of the pumped water is directed to a box-type passage at the backside of the PV module, and then connect to the water pipe and drain to the farmland. Two various flow rates of 5 and 10 L/min were tested. The results showed two proposed cases have a bit difference in their outputs. Accordingly, the temperature of modified cases did not pass beyond 36°C while, the temperature of the conventional module reaches to 72°C. This temperature reduction leads to about 50% higher electrical efficiency. From the output power point of view, more than 45% increase was observed. Also, an environment evaluation is performed and it was found that the present improvement can reduce emission of 34.57 tons CO2, annually.
F. O. Aweda; T. K. Samson
Abstract
Solar radiation is an important parameter in the study of electricity and/or thermal system installation. Direct monthly irradiance data measurements of the earth’s horizontal surface irradiance for the year 1985 to 2019 for nine stations (Sokoto, Birnin Kebbi, Maiduguri, Ilorin, Calabar, Port-Harcourt, ...
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Solar radiation is an important parameter in the study of electricity and/or thermal system installation. Direct monthly irradiance data measurements of the earth’s horizontal surface irradiance for the year 1985 to 2019 for nine stations (Sokoto, Birnin Kebbi, Maiduguri, Ilorin, Calabar, Port-Harcourt, Enugu, Iwo, and Ikeja) were collected from the achieve of HelioClim satellite website. The stationarity of the series was determined using the time plot of the irradiance data between the periods under study but the formal test of stationarity was carried out using the Augmented Dickey-Fuller (ADF) test with a p-value less than 0.05 signifying stationarity. Different autoregressive integrated moving average (ARIMA) models were fitted to the irradiance data for each of the selected stations. The results revealed that Sokoto, Maiduguri, and Kebbi have their maximum solar irradiance at about and their minimum at about , while Ilorin has its maximum solar irradiance at about and its minimum solar irradiance at about . Ikeja, Iwo and Port-Harcourt, Calabar and Enugu have their maximum solar irradiance and their minimum solar irradiance at about . It is therefore concluded that for Kebbi, Iwo and Maiduguri, the best model was ARIMA (3,0,3), for Calabar and Sokoto, it was ARIMA (2,0,2) while for other locations like Enugu, Ikeja, Ilorin and Port Harcourt, ARIMA (2,0,3) was the best model for forecasting irradiance in these study areas. The forecasted values of irradiance between January till December 2020 with its corresponding 95% confidence levels indicate good prediction of solar irradiance for future occurrence.
V. N. Kanthe
Abstract
In this research work, the effect of rice husk ash (RHA) along with and without superplasticizer (SP) on the properties of concrete was investigated. The good workability and compaction is key parameter for strength and durability of concrete, and it may achieved by adding SP in to the concrete. ...
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In this research work, the effect of rice husk ash (RHA) along with and without superplasticizer (SP) on the properties of concrete was investigated. The good workability and compaction is key parameter for strength and durability of concrete, and it may achieved by adding SP in to the concrete. In India RHA is available in huge quantity. It is byproduct of agriculture. In present research ordinary portland cement (OPC) was replaced by 10 to 50% RHA. The fresh properties as workability and hardened properties of concrete as compressive strength were examined. For durability test water absorption, acid attack and sulphate attack tests were conducted.The test results show that at 10%RHA with SP the maximum strength of concrete was attained with respect to control concrete mix (CM). The satisfactory test results were shown for durability and strength. Such kind of blend concrete is more efficient to enhance the properties of concrete which reduce the consumption of cement. The utilization of agricultural byproduct makes concrete sustainable and reduce environmental problems.
M. E. Kashfi; R. Kouhikamali; G. Khayati
Abstract
In this study, a mathematical model was used to predict the dynamic behaviour of the system under conditions of imperfect mixing in an Anaerobic Digestion (AD) process. To evaluate the system performance, the effect of mixing parameters by calculating the quantities of methane gas produced, system power, ...
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In this study, a mathematical model was used to predict the dynamic behaviour of the system under conditions of imperfect mixing in an Anaerobic Digestion (AD) process. To evaluate the system performance, the effect of mixing parameters by calculating the quantities of methane gas produced, system power, and effluent quality was investigated. Numerical results showed that with an increase in the mixing rate (α) by 20%, methane production rate, power production, and the effluent COD removal efficiency of the system increased by 19%, 19% and 12%, respectively. At an equal mixing rate, the amount of methane produced in influent with a concentration of 12.1% was 4.5 times higher than the influent with a concentration of 2.5%, while no significant change was observed in the effluent quality. Additionally, it was found that the mixing rate effect is more important than the mean cell retention time in the anaerobic reactor. The best fitted correlations for methane production rate and effluent COD removal efficiency using regression analogy at different organic loads of wastewater are presented.
Chemical Engineering
M. Imani-Hassanloui; M. R. Maraki; Z. Taghimalek; H. Tagimalek
Abstract
Nowadays, vending is the most important pillar of a production set. The positive and significant points of the manufactured parts are attained by interviewing with the customer, sending a questionnaire to the customer, testing the market, investigating the quality and reliability of new products, probing ...
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Nowadays, vending is the most important pillar of a production set. The positive and significant points of the manufactured parts are attained by interviewing with the customer, sending a questionnaire to the customer, testing the market, investigating the quality and reliability of new products, probing the reports and product quality of competitors. Aimed at predicting the type of leadership in reverse engineering, based on “Voice of Customer” (VOC), between the Iran Khodro Company’s (IKC) managers (case study of Peugeot 405 brake pump shell), the present study was conducted. Using descriptive-correlation research method, about 90 managers were randomly selected in several categories according to gender, age and years of service, proportional to the size of each category. Three questionnaires of “Oregon and Kanowski Organizational Citizenship Behavior” (OKOCB), “Fry Spiritual Leadership” (FSL), and researcher-made “Charismatic Leadership” (CL) were utilized to collect the research data. To measure the reliability rate using Cronbach's alpha coefficient, this item was obtained for all three questionnaires of the OKOCB, FSL and CL behavior (α = 0.92, 0.81 and 0.85) respectively. Collecting the data, they were analyzed using multiple regression analysis and based on the research hypotheses. The results indicated that there is a positive and significant relationship between the dimensions of SL and organizational citizenship behavior, and also between the CL and the organizational citizenship behavior. The results of structural equation modeling also showed that SL with a path coefficient 0.7 is able to affect overall quality management (t ≥ 1.96, p≤ 0.05).
Mass Transfer
A. Bagheri; S. Karimian Aliabadi; K. Ghaemi Osgouie; M. Shafaee
Abstract
In this experimental work, the 2-phase air-water non-boiling ascending fluid flow in a vertical tube with helical corrugations has been investigated. The results showed that the head loss values decreased with an increase of the volume fraction. Also, by comparing the head loss values for each corrugation ...
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In this experimental work, the 2-phase air-water non-boiling ascending fluid flow in a vertical tube with helical corrugations has been investigated. The results showed that the head loss values decreased with an increase of the volume fraction. Also, by comparing the head loss values for each corrugation pitch, it can be observed that as the corrugation pitch goes down, the head loss values significantly increase. As a result, the intensity of vapors increases perpendicular to the main flow of water, which leads to an increase in the intensity of disturbance in the flow, and then the head loss increases. The Nusselt number goes down when the volume fraction experiences an increment. Looking at the figures related to Nusselt number, it is easy to see that the curves are drawn for a constant air flow rate. Consequently, an increase in volume fraction (VF) is equal to a decrease in the water flow rate. By reducing the water flow rate, the intensity of the main flow is reduced the intensity of turbulence is also reduced and the heat transfer coefficient is reduced. As a result, the amount of heat transfer has increased due to air injection. It should be noted that pipes with the largest corrugation pitch had the best Cost-benefit ratio (C.B.R.) factor values (which means the lowest value). This means that air injection in larger corrugation pitch tubes was more beneficial than in smaller corrugation pitch tubes.
R. Farzandi; H. Nayebzadeh; M. Hokmabadi; N. Saghatoleslami
Abstract
The effect of cultivation culture on the biodiesel yield produced from in-situ transesterification of Chlorella vulgaris microalgae was assessed. Firstly, the algae were cultivated in Moh202, sterilized wastewater (SW), unsterilized wastewater (USW) mediums. It was found that around ten days were suitable ...
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The effect of cultivation culture on the biodiesel yield produced from in-situ transesterification of Chlorella vulgaris microalgae was assessed. Firstly, the algae were cultivated in Moh202, sterilized wastewater (SW), unsterilized wastewater (USW) mediums. It was found that around ten days were suitable to receive maximized growth of microalgae; while, maximum and minimum growth was detected in Moh202 and SW media. Before assessment, the effect of cultivation medium on the biodiesel content, the transesterification reaction conditions such as catalyst (NaOH) concentration, reaction time and amount of methanol were investigated by algae cultivated in Moh202 medium via fractional factorial design as statistical methodology. In the range of the study, catalyst concentration and reaction time were the most important effective parameters on the biodiesel yield. Moreover, the interaction between reaction time with catalyst concentration and amount of methanol was also important. In short reaction time and its interaction with catalyst concentration had positive effect, while catalyst concentration, amount of methanol and interaction of reaction time and amount of methanol had negative impact on the biodiesel yield. The yields of the algae cultivated in Moh202, sterilized and unsterilized wastewater media at the optimum conditions of 1 wt.% of catalyst, 9 mL methanol/g biomass and reaction time of 4 hours were 95.5%, 83.9% and 75.5%, respectively. Although the difference between biodiesel yields of Chlorella vulgaris Microalgae cultivated in the wastewater medium compared to sterilized wastewater medium was observed, wastewater can be used as a medium for cultivation of algae for biodiesel production to reduce the biodiesel production costs.
A. Nurdin; D. A. Himawanto; S. Hadi
Abstract
Water systems such as pipelines, pumping stations and other channels in horizontal flow have the potential as pico scale hydropower. This study aims to observe the effect of the number of blades and the blade angle on the electric power generation in the small bulb turbine on horizontal flow. This study ...
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Water systems such as pipelines, pumping stations and other channels in horizontal flow have the potential as pico scale hydropower. This study aims to observe the effect of the number of blades and the blade angle on the electric power generation in the small bulb turbine on horizontal flow. This study also observes how the number of blades and blade angle affected the electrical power generated using analysis of variance. The level on the parameter number of blades used was 4, 5, 6, and 7 blades, while the level parameters on the blade angle were 15, 20, 25, and 30 degrees and each level was tested 4 replication at the discharge of 13 L/s. This paper shows the results of turbine performance in the form of angular velocity, electric power, efficiency, and the test results of the analysis of variance using SPSS 17 software. The results of the study show the number of blades 5 with a 20 degree blade angle of the best performance compared another the number of blades and the blade angle with an efficiency of about 50%. The results of the analysis of variance show the blade angle of the blade has a more dominant effect on electrical power than the number of blades.
Renewable Energy
B. Khorram; I. Mirzaee; S. Jafarmadar
Abstract
The main purpose of this study is to evaluate the thermodynamic and economic performance of using a solar chimney and wind turbine to help generate electricity in a multigeneration system. The proposed system is designed to generate power, heating, cooling, hot water, and steam. Parametric studies were ...
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The main purpose of this study is to evaluate the thermodynamic and economic performance of using a solar chimney and wind turbine to help generate electricity in a multigeneration system. The proposed system is designed to generate power, heating, cooling, hot water, and steam. Parametric studies were conducted to evaluate the effects of various parameters such as Brayton cycle turbine inlet pressure, organic Rankine cycle turbine inlet temperature, solar radiation, wind speed, and absorption refrigeration cycle evaporator temperature on the system efficiency. The effects of these parameters on the energy, exergy, and economic efficiencies of the whole system were investigated. The results showed that the highest energy efficiency and total exergy of the multigeneration system were 22.12% and 11.4%, respectively. Also, the total power generation capacity of the studied system was calculated to be 2103 kW. The results also depicted that the highest rate of exergy destruction for the main components of the system is found in the parabolic dish solar collector. Increasing the turbine inlet pressure, the average wind velocity of the wind turbine and, evaporator temperature increasing of absorption refrigeration cycle has a positive effect on the efficiency of the proposed system.
A. G. Adeniyi; J. O. Ighalo
Abstract
In this preliminary investigation, the production of liquid fertilizer from rock phosphate and dolomite in Nigeria using the nitrophosphate is evaluated. Rock phosphate was obtained from Sokoto state, Nigeria. Dolomite was obtained from Edo state, Nigeria. This work contains a detailed description of ...
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In this preliminary investigation, the production of liquid fertilizer from rock phosphate and dolomite in Nigeria using the nitrophosphate is evaluated. Rock phosphate was obtained from Sokoto state, Nigeria. Dolomite was obtained from Edo state, Nigeria. This work contains a detailed description of the procedure and the associated chemical reactions. There are also important explanations of some physical observations and their possible implications in a large scale process. The time frame for each batch should not exceed 1 h considering the reaction rates and the temperatures are likely not to exceed 80oC at any point in the process. It was observed that the potassium, phosphorus and nitrogen content of both fertilizers are similar but the calcium content of the product from dolomite was higher than the other products. Furthermore, possible process design modifications based on these physical observations are proposed in line with product quality, safety, cost and other considerations. The process was ultimately successful and recommendations were made based on several aspects of the process.
S. W. Igo; N. Kokou; A. Compaoré; P. Kalifa; G. L. Sawadogo; D. Namoano
Abstract
This work is devoted to the evaluation of the performance of a typical fired-wood oven commonly used in the rotisserie sector in Burkina Faso. The methodology used is based on the energy balance of the oven. For this purpose, 20 liters of water were heated up to 90 °C. The difference in water temperature ...
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This work is devoted to the evaluation of the performance of a typical fired-wood oven commonly used in the rotisserie sector in Burkina Faso. The methodology used is based on the energy balance of the oven. For this purpose, 20 liters of water were heated up to 90 °C. The difference in water temperature at the start and at the end of the experiment makes it possible to calculate the amount of energy consumed by the load. The temperatures of the walls as well as that of the ambient were recorded to evaluate the losses by convection towards the environment. The losses through the fumes have been estimated from the energy balance. The results show that the dominant losses are those of fumes (about 55 % of the energy consumed). The losses through the walls are relatively large (26 %). The efficiency of the oven is around 19 %, which is very low. These results show that these equipment are inefficient and contribute significantly to the waste of wood at the national level.
S. Abdoly Naser; F. Haghparast; M. Singery; H. Sattari Sarbangholi
Abstract
Iranian vernacular architecture has rich experiences in terms of coordinating with its surroundings. although, high energy consumption was one of the major concerns in the past decades. According to statistics presented by Iranian Statistics Center, 40% of the country's energy consumption is relevant ...
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Iranian vernacular architecture has rich experiences in terms of coordinating with its surroundings. although, high energy consumption was one of the major concerns in the past decades. According to statistics presented by Iranian Statistics Center, 40% of the country's energy consumption is relevant to the construction industry. However, about 70% of consumption is used solely for space heating and cooling. In the meantime, windows have a significant influence on the thermal performance. Ganjei-Zade House in Tabriz is one of the monuments and includes two parts. The north side of Qajar era and the western side was added to the former building in Pahlavi era. The present article deals with the study of the evolution of windows from Qajar to Pahlavi in Ganjei-zade house and the amount of heat dissipation from windows. These evaluations has been carried out by simulating Ganjei-zade house in the DesignBuilder software. The research related to this article was conducted based on analytic and comparative method and the purpose is to provide the important criteria for windows in residential buildings in the cold climate of Tabriz considering native architecture solutions in order to reduce heat dissipation. The conducted calculations confirm that the amount of heat losses from windows from Qajar to Pahlavi era, has been reduced by 22.2% and the amount of heat dissipation per square meter of windows from Qajar period to Pahlavi was decreased by 58.33%.
S. O. Ayoola; C. E. Ejikeme; O. Folami
Abstract
The toxicity effects of crude oil were investigated in the laboratory. Triplicates of (T1) 0.25mg/l, (T2) 1.0mg/l, (T3) 2.25mg/l, (T4) 5.0mg/l and (T5) 7.5mg/l concentration of crude oil exposed to Sarotherodon melanotheron species. The acute toxicity test of crude oil when tested against Sarotherodon ...
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The toxicity effects of crude oil were investigated in the laboratory. Triplicates of (T1) 0.25mg/l, (T2) 1.0mg/l, (T3) 2.25mg/l, (T4) 5.0mg/l and (T5) 7.5mg/l concentration of crude oil exposed to Sarotherodon melanotheron species. The acute toxicity test of crude oil when tested against Sarotherodon melanotheron revealed that the derived toxicity index LC50 was 0.925mg/l. On computing Toxicity Factor (TF), using 96 hours. LC50, crude oil was found to be very toxic to the Sarotherodon melanotheron juvenile. The mean frequencies of micronucleus in S. melanotheron exposed to different concentration of crude oil ranged from 3.01±0.50 – 27.48±2.71. The lowest value was 3.01±0.50 in T0 (control) while the highest value of 27.48 ± 2.71 wasrecorded in fishes exposed to (T5) 7.5mg/l test solutions. The results obtained from micronucleus test showed that T5 had the highest number of micro-nucleated cells followed by T4 while T1, T2, T3, and T0 significantly increased with the concentration across the test chemical. Sarotherodon melanotheron showed various degrees of sensitivity in monitoring genetic damage especially in the normal nucleus (NN). The chromosomal aberrations indicate formation of vacuolated nucleus (VC), micronucleus (MN) and bi-nucleated cells (BN) showed marked increase in occurrence in the following concentrations of occurrences; T1, T2, T3, T4 and T5, respectively. Test solution of concentration T5 (7.5mg/l) was observed to possess fish with highest level of micronucleus frequencies followed by T4 (5.0mg/L). There were significant differences in increasing T5 having the highest number of micro-nucleated cells (MN) with a trend in increasing bi-nucleus cells (BN), polymorphic nucleus (PM), kidney shape nucleus (KN) and bleb nucleus (BLN) cells, respectively, as the concentration of the test chemical increased. The results also showed that there was a significant difference in the effects of the T5 and other test concentrations (T1, T2, T3, T4 and T0). The response of Sarotherodon melanotheron established that is a better model for bioassay test used as a pollution bio indicator. Pollutants even in a very low concentration if present for a long duration may affect the nucleus. Hence, the use of any kind of substances such as crude oil products and synthetic chemicals in aquaculture field should be carefully monitored and used under proper guidance.
A. Singh; K. K. Singh
Abstract
The problem of air pollution has ramifications for human health, the environment, and a variety of living sectors. Modern technology has resulted in air pollution and its damaging effects, while also driving the world to make every effort to overcome its negative repercussions. The origin, chemical composition, ...
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The problem of air pollution has ramifications for human health, the environment, and a variety of living sectors. Modern technology has resulted in air pollution and its damaging effects, while also driving the world to make every effort to overcome its negative repercussions. The origin, chemical composition, size, and mode of discharge inside or outdoor environments have all been proven to be air pollutants. Industrial, commercial, mobile, urban, regional, farm, and natural sources of indoor pollutants include cooking and combustion, particle matter rehabilitation, materials used for resources, temperature control, and consumer items, smoking, heating, and organic compounds. Indoor Pollutant Sources Air pollution has an impact on the body, including respiratory systems and heart disorders. Asthmatics, bronchiolitis, lung disease, cardiovascular problems, central nervous system malfunction, and skin conditions are the most common respiratory disorders, as are chronic obstructive pulmonary disease (COPD). The challenges posed by outdoor air pollution are public health risks such as cardiovascular disease, respiratory ailments, COPD, and world-class asymmetry. The impacts of human activities on air quality and climate change may be realized at several sizes, ranging from urban to regional to continental to global. Rapid population growth and increased energy consumption are the principal drivers of massive amounts of hazardous chemicals and greenhouse gases entering the atmosphere, with serious consequences for health and the environment.
O. Hadad; O. Soltani; H. Azizian; V. Mam Ghaderi
Abstract
Due to the increasing use of concrete, researchers and engineers are constantly tried to improve its mechanical and physical properties as well as its efficiency. Hence, they have made use of the most diverse products and the most modern concere technologies. In the present study, oak bark ash and macro ...
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Due to the increasing use of concrete, researchers and engineers are constantly tried to improve its mechanical and physical properties as well as its efficiency. Hence, they have made use of the most diverse products and the most modern concere technologies. In the present study, oak bark ash and macro fly ash have been used as the most widely used pozzolans in the concrete industry. The parameters of concrete and the percentages of materials used in its structure remained constant, but different percentages of oak bark ash and macro fly ash have been added to the mix design. Brazilian method and bending strength of concrete was applied. The parameters of concrete density, concrete consistency, compressive strength, and tensile strength have been investigated..Therefore, the existing materials required necessary tests; based on obtained resulted, an optimal design for the concrete mix was introduced from which the necessary specimens were taken into consideration. Then, oak bark ash was used as an additive, in proportions of 0.2 and 0.4% by the total weight of cement, and macro fly ash was used to replace cement as a variable in various proportions of 5, 10, 15 and 20% by total weight of cement. Based on the existing variables and the control design, a total of 15 groups of mix designs were introduced. The statistical population includes 45 cubic specimens (15×15×15), and 45 cylindrical specimens (15×30) for tensile strength test using Brazilian method. Also 45 bending beam specimens having dimensions of 10×10×50 were examined. Finally, after analysis of the obtained results, we dentified the superior mix design had the best performance and that both additives affected all studied parameters, including concrete consistency, density, compressive strength, tensile strength, and bending strength of concrete. However, macro fly ash had a great effect on the conrete strength. The obtained results also indicated that excessive use of any additive could have adverse effects on the mechanical properties of the concrete.
