A 3.6 m3 pilot plastic digester for family generation of biogas was designed, constructed and evaluated through physico -chemical studies using 50% cow dung and 50% kitchen wastes. The ash content of waste increased after digestion while the fibre and fat contents of the waste was 5.10 and 1.05% but significantly (p<0.05) decreased to 2.49 and 0.70% after digestion. The carbohydrate content of the waste was 11.02% which significantly (p<0.05) decreased to 7.91%. The volatile solid content of 50% cow dung + 50% cassava peel + yam peels + vegetable was 11.10%. The biochemical oxygen demand was 44.58% while the chemical oxygen demand was 139.20% before digestion but decreased significantly (p<0.05) after digestion. The pH of 50% cow dung + 50% cassava + yam peels + vegetable waste during digestion increased from 6.71 at day of charging to 6.81 at the 8th day after which it began to fluctuate between 6.68 and 6.85 throughout the retention period. Afternoon temperatures of both ambient and slurry were within the mesophilic (30 and 40°C) temperature which was higher than the morning and evening temperatures. The production of biogas started at the 2nd day by producing 406 L and increased each day till day 8, by producing 738 L and after which its production began to fluctuate between 572 and 718 L/day. Early biogas flammability was observed on the 4th day for 50% cow dung + 50% cassava + yam peels + vegetable. At the point of flaming, the methane content of the biogas increased significantly (p<0.05) to 65.65%, while the carbon dioxide decreased significantly (p<0.05) to 25.15%, for 50% cow dung + 50% cassava + yam peels + vegetable. The average biogas (0.601 to 0.505 m3/day) produced from the waste using 3.6 m3 capacity plastic bio-digester could be sufficient to cook three times a day for household of 3 to 4 persons. Key words: Bio digester, ash content, cassava, cow dung, biogas.
{"title":"Design and fabrication of 3.60 m3 household plastic bio digester loaded with kitchen waste and cow dung for biogas generation","authors":"C. Nwankwo, J. I. Eze, Francis Chigozie Okoyeuzu","doi":"10.5897/SRE2017.6516","DOIUrl":"https://doi.org/10.5897/SRE2017.6516","url":null,"abstract":"A 3.6 m3 pilot plastic digester for family generation of biogas was designed, constructed and evaluated through physico -chemical studies using 50% cow dung and 50% kitchen wastes. The ash content of waste increased after digestion while the fibre and fat contents of the waste was 5.10 and 1.05% but significantly (p<0.05) decreased to 2.49 and 0.70% after digestion. The carbohydrate content of the waste was 11.02% which significantly (p<0.05) decreased to 7.91%. The volatile solid content of 50% cow dung + 50% cassava peel + yam peels + vegetable was 11.10%. The biochemical oxygen demand was 44.58% while the chemical oxygen demand was 139.20% before digestion but decreased significantly (p<0.05) after digestion. The pH of 50% cow dung + 50% cassava + yam peels + vegetable waste during digestion increased from 6.71 at day of charging to 6.81 at the 8th day after which it began to fluctuate between 6.68 and 6.85 throughout the retention period. Afternoon temperatures of both ambient and slurry were within the mesophilic (30 and 40°C) temperature which was higher than the morning and evening temperatures. The production of biogas started at the 2nd day by producing 406 L and increased each day till day 8, by producing 738 L and after which its production began to fluctuate between 572 and 718 L/day. Early biogas flammability was observed on the 4th day for 50% cow dung + 50% cassava + yam peels + vegetable. At the point of flaming, the methane content of the biogas increased significantly (p<0.05) to 65.65%, while the carbon dioxide decreased significantly (p<0.05) to 25.15%, for 50% cow dung + 50% cassava + yam peels + vegetable. The average biogas (0.601 to 0.505 m3/day) produced from the waste using 3.6 m3 capacity plastic bio-digester could be sufficient to cook three times a day for household of 3 to 4 persons. \u0000 \u0000 \u0000 \u0000 Key words: Bio digester, ash content, cassava, cow dung, biogas.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"130-141"},"PeriodicalIF":0.0,"publicationDate":"2017-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2017.6516","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44590666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is currently great emphasis on research regarding various aspects of energy sources but the question of optimum usage of the energy is equally important. This work seeks to produce an economic computer-aided design of a fire-clay pot based on conditions that give minimum cost per unit of usage time for the consumer. A percentage of energy loss from the fuel to the environment due to inefficiency of the heating system was incorporated as a variable in the calculations. Graphs are presented to indicate the calculated optimum economic pot thicknesses at various values of the inner radii. For a common inner radius of 6.0 cm and 75% energy loss, the optimum pot thicknesses for cooking at temperatures of 60, 80, and 100°C were found to be 9.6, 12.0, and 13.8 mm, respectively. The results show that the economic thickness increases with increase in both inner radius and cooking temperature. It has also been established that the operational cost increases with increase in temperature even at the optimum economic thickness. This work includes a study of the calorimetric value of the most commonly used types of wood and charcoal fuel, in Zambia, for clay-pot cooking. These types of fuel come from the four trees locally known as the Musamba, Mubanga, Mutondo, and Mutiti. Several wood and charcoal samples from all these trees were collected and experimentally analysed using an oxygen bomb calorimeter to determine the amount of heat energy in Joules which can be realizable per kilogram of the fuel materials. Key words: Calorific value, economic operational cost, computer-aided design.
{"title":"Determination of the most economic thickness and energy source in the design of local hemispherical clay pots","authors":"C. Fwalo, A. Habanyama, G. Baliga, J. Pondo","doi":"10.5897/SRE2016.6473","DOIUrl":"https://doi.org/10.5897/SRE2016.6473","url":null,"abstract":"There is currently great emphasis on research regarding various aspects of energy sources but the question of optimum usage of the energy is equally important. This work seeks to produce an economic computer-aided design of a fire-clay pot based on conditions that give minimum cost per unit of usage time for the consumer. A percentage of energy loss from the fuel to the environment due to inefficiency of the heating system was incorporated as a variable in the calculations. Graphs are presented to indicate the calculated optimum economic pot thicknesses at various values of the inner radii. For a common inner radius of 6.0 cm and 75% energy loss, the optimum pot thicknesses for cooking at temperatures of 60, 80, and 100°C were found to be 9.6, 12.0, and 13.8 mm, respectively. The results show that the economic thickness increases with increase in both inner radius and cooking temperature. It has also been established that the operational cost increases with increase in temperature even at the optimum economic thickness. This work includes a study of the calorimetric value of the most commonly used types of wood and charcoal fuel, in Zambia, for clay-pot cooking. These types of fuel come from the four trees locally known as the Musamba, Mubanga, Mutondo, and Mutiti. Several wood and charcoal samples from all these trees were collected and experimentally analysed using an oxygen bomb calorimeter to determine the amount of heat energy in Joules which can be realizable per kilogram of the fuel materials. \u0000 \u0000 Key words: Calorific value, economic operational cost, computer-aided design.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"120-129"},"PeriodicalIF":0.0,"publicationDate":"2017-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2016.6473","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49551360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Energy consumption by occupants during utilization phase concerns the increase of global warming potential and a shortage of energy resources. Energy consumption in an effective way decreases the risk of global warming. Use of materials with high embodied energy and embodied carbon in building components may improve the energy performance of the building, but it can ameliorate global warming. The issue of Life Cycle is quite new in the Middle East, so is it effective or does it work in developing countries. One of the goals of this study is to use three different wall types in a two-story office with close embodied energy and U-value (overall heat transfer coefficient) and compare the performance of each wall in the building from the Life Cycle point of view. Subsequently, analyzing the importance of other factors such as embodied carbon and transportation in choosing appropriate material in the construction sector. According to this study, even in countries like Iran (‘‘which holds the world's fourth-largest proved crude oil reserves and the world's second-largest natural gas reserves’’) with very low amount of database about the embodied energy, the right material should be chosen to reduce the fuel consumption and CO2 emission. Key words: Life Cycle Assessment (LCA), office, embodied energy.
{"title":"Optimizing the life cycle of an office building at semiarid region","authors":"Pooya Pakmehr, M. E. Karaguler","doi":"10.5897/SRE2017.6509","DOIUrl":"https://doi.org/10.5897/SRE2017.6509","url":null,"abstract":"Energy consumption by occupants during utilization phase concerns the increase of global warming potential and a shortage of energy resources. Energy consumption in an effective way decreases the risk of global warming. Use of materials with high embodied energy and embodied carbon in building components may improve the energy performance of the building, but it can ameliorate global warming. The issue of Life Cycle is quite new in the Middle East, so is it effective or does it work in developing countries. One of the goals of this study is to use three different wall types in a two-story office with close embodied energy and U-value (overall heat transfer coefficient) and compare the performance of each wall in the building from the Life Cycle point of view. Subsequently, analyzing the importance of other factors such as embodied carbon and transportation in choosing appropriate material in the construction sector. According to this study, even in countries like Iran (‘‘which holds the world's fourth-largest proved crude oil reserves and the world's second-largest natural gas reserves’’) with very low amount of database about the embodied energy, the right material should be chosen to reduce the fuel consumption and CO2 emission. \u0000 \u0000 \u0000 \u0000 Key words: Life Cycle Assessment (LCA), office, embodied energy.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"113-119"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2017.6509","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46349217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Induction motors are currently used in many industrial applications. Thus, their control techniques have received a lot of interest. An efficient method of induction motor control is the Direct Torque Control (DTC). It is considered particularly interesting since it is independent of machine rotor parameters and requires no speed or position sensors. This paper presents a simulation of a DTC strategy for three-phase induction motors based on the Field Programmable Gate Array (FPGA) technology. The real controller is not experimentally tested. A specific methodology for the hardware description language in VHSIC Hardware Description Language (VHDL) is presented. This paper summarizes the prior work before implementing the experimental FPGA control of an induction motor. This methodology allows one to verify the behavior of the VHDL codes before their implementation, reducing the risks of significant changes when implemented. The VHDL design technique for DTC-based speed control is designed through the descriptions of coordinate transformation, speed controller, stator flux and torque estimator, stator flux and torque controller, and stator flux position detector. The simulation is performed using the MATLAB/Simulink, DSP Builder, and Quartus II software, on an Altera DE2-115 board. Simulation results verify the validity of the proposed method. Key words: Digital control, induction motor, digital signal processing, VHSIC Hardware Description Language (VHDL).
{"title":"Design and simulation of direct torque control of induction motors using VHSIC Hardware Description Language (VHDL)","authors":"C. D. Costa, Christian Santin","doi":"10.5897/SRE2017.6501","DOIUrl":"https://doi.org/10.5897/SRE2017.6501","url":null,"abstract":"Induction motors are currently used in many industrial applications. Thus, their control techniques have received a lot of interest. An efficient method of induction motor control is the Direct Torque Control (DTC). It is considered particularly interesting since it is independent of machine rotor parameters and requires no speed or position sensors. This paper presents a simulation of a DTC strategy for three-phase induction motors based on the Field Programmable Gate Array (FPGA) technology. The real controller is not experimentally tested. A specific methodology for the hardware description language in VHSIC Hardware Description Language (VHDL) is presented. This paper summarizes the prior work before implementing the experimental FPGA control of an induction motor. This methodology allows one to verify the behavior of the VHDL codes before their implementation, reducing the risks of significant changes when implemented. The VHDL design technique for DTC-based speed control is designed through the descriptions of coordinate transformation, speed controller, stator flux and torque estimator, stator flux and torque controller, and stator flux position detector. The simulation is performed using the MATLAB/Simulink, DSP Builder, and Quartus II software, on an Altera DE2-115 board. Simulation results verify the validity of the proposed method. \u0000 \u0000 \u0000 \u0000 Key words: Digital control, induction motor, digital signal processing, VHSIC Hardware Description Language (VHDL).","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"103-112"},"PeriodicalIF":0.0,"publicationDate":"2017-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2017.6501","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48894951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The city identity, taking form with pysical, cultural, socio-economical, historical and stylistic factors, carrying peculiar characteristics in each city, formed by the citizens and their lifestyles, constantly developing and reflecting the sustainable urban concept, is a completion of concepts. Urban identity elements, either they are natural or human artifact, are the witnesses of the past and form our cultural heritage. Conserving our cultural heritage without bearing heavy losses, transferring to the future generations are important in terms of social and cultural sustainability concepts and are some of main duties. However, the change in urbanization, population increase, life style due to the social structure and depending on these reasons such as functional, physical and economical obsolescence cause the buildings creating our cultural heritage, witnessing our past and the physical environment consisting of these buildings to alter or to undergo the perishing process. In this context, the aim of the study is the evaluation of preservation and renewal practices done in Ankara Hamamonu province in terms of sustainable urban preservation principles, according to the relevant legislation in force in the context of urban transformation and urban renewal practices donein recent years. Key words: Sustainable preservation, historical city centre, Ankara Hamamonu.
{"title":"Evaluation of sustainable urban preservation concept via Ankara Hamamn example","authors":"Aşut Funda, I. Bayer","doi":"10.5897/SRE2015.6369","DOIUrl":"https://doi.org/10.5897/SRE2015.6369","url":null,"abstract":"The city identity, taking form with pysical, cultural, socio-economical, historical and stylistic factors, carrying peculiar characteristics in each city, formed by the citizens and their lifestyles, constantly developing and reflecting the sustainable urban concept, is a completion of concepts. Urban identity elements, either they are natural or human artifact, are the witnesses of the past and form our cultural heritage. Conserving our cultural heritage without bearing heavy losses, transferring to the future generations are important in terms of social and cultural sustainability concepts and are some of main duties. However, the change in urbanization, population increase, life style due to the social structure and depending on these reasons such as functional, physical and economical obsolescence cause the buildings creating our cultural heritage, witnessing our past and the physical environment consisting of these buildings to alter or to undergo the perishing process. In this context, the aim of the study is the evaluation of preservation and renewal practices done in Ankara Hamamonu province in terms of sustainable urban preservation principles, according to the relevant legislation in force in the context of urban transformation and urban renewal practices donein recent years. \u0000 \u0000 \u0000 \u0000 Key words: Sustainable preservation, historical city centre, Ankara Hamamonu.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"88-102"},"PeriodicalIF":0.0,"publicationDate":"2017-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2015.6369","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43681347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Halophytes are plants that complete their life cycle in saline environments. Halophytes can therefore be viewed as potential gene sources for genetic manipulation of economically important crop plants. In this study the influence of salinity on potential difference (PD) and surface pH of root cortical cells was investigated. The effect of the metabolic inhibitor, potassium cyanide (KCN), on PD of the root cells was also investigated. A study of the electrophysiological characteristics of the membrane of the root cortical cells showed that there were two components to the root cell PD. One component (diffusional) was affected by the increasing NaCl concentration in the growth medium, while the other component (electrogenic) remained unaffected by the NaCl concentration up to 200 mol m-3. There is evidence to suggest that this electrogenic component of the PD was maintained by an efflux pump which presumably controls ion uptake and indirectly growth. It is concluded that this electrogenic efflux pump is a major factor contributing to salt tolerance in Sesuvium portulacastrum. Key words: Electrogenic pumps, halophyte, membrane potential difference, salinity, Sesuvium portulacastrum.
{"title":"Effect of salinity on transmembrane potential of the roots of Sesuvium portulacastrum (L.) L.","authors":"B. Moseki","doi":"10.5897/SRE2014.6056","DOIUrl":"https://doi.org/10.5897/SRE2014.6056","url":null,"abstract":"Halophytes are plants that complete their life cycle in saline environments. Halophytes can therefore be viewed as potential gene sources for genetic manipulation of economically important crop plants. In this study the influence of salinity on potential difference (PD) and surface pH of root cortical cells was investigated. The effect of the metabolic inhibitor, potassium cyanide (KCN), on PD of the root cells was also investigated. A study of the electrophysiological characteristics of the membrane of the root cortical cells showed that there were two components to the root cell PD. One component (diffusional) was affected by the increasing NaCl concentration in the growth medium, while the other component (electrogenic) remained unaffected by the NaCl concentration up to 200 mol m-3. There is evidence to suggest that this electrogenic component of the PD was maintained by an efflux pump which presumably controls ion uptake and indirectly growth. It is concluded that this electrogenic efflux pump is a major factor contributing to salt tolerance in Sesuvium portulacastrum. \u0000 \u0000 \u0000 \u0000 Key words: Electrogenic pumps, halophyte, membrane potential difference, salinity, Sesuvium portulacastrum.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"81-87"},"PeriodicalIF":0.0,"publicationDate":"2017-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2014.6056","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42812571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Rahman, W. Liaqat, K. Khattak, M. Choudhary, Atif Kamil, M. Zeb
In the ongoing phytochemical study, an effort was made to investigate cytotoxicity of various crude fractions of aerial parts of Indigofera heterantha. The results obtained revealed that all the fractions including n-hexane, ethyl acetate, methanol and residue showed brine shrimp (Artemia salina Leach) cytotoxicity activity. The data obtained revealed the medicinal importance of the plant and will help the researchers to exploit the phytochemicals for biological activities (cytotoxicity). Key words: Indigofera heterantha, cytotoxicity, aerial parts.
{"title":"Cytotoxicity of aerial parts of Indigofera heterantha","authors":"T. Rahman, W. Liaqat, K. Khattak, M. Choudhary, Atif Kamil, M. Zeb","doi":"10.5897/SRE2014.5814","DOIUrl":"https://doi.org/10.5897/SRE2014.5814","url":null,"abstract":"In the ongoing phytochemical study, an effort was made to investigate cytotoxicity of various crude fractions of aerial parts of Indigofera heterantha. The results obtained revealed that all the fractions including n-hexane, ethyl acetate, methanol and residue showed brine shrimp (Artemia salina Leach) cytotoxicity activity. The data obtained revealed the medicinal importance of the plant and will help the researchers to exploit the phytochemicals for biological activities (cytotoxicity). \u0000 \u0000 \u0000 \u0000 Key words: Indigofera heterantha, cytotoxicity, aerial parts.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"77-80"},"PeriodicalIF":0.0,"publicationDate":"2017-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2014.5814","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43880740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vidhya Sivasailanathan, Prabhat Kumar, S. Sagadevan
The intensity of the ionizing radiations can be reduced by allowing them to pass through certain materials and such external materials are known as shields. The shielding material is often chosen based on the type and intensity of the radiation. The radionuclides of standard radioactive sources for calibration purpose or therapeutic use, the irradiated components that produce ionizing radiation of high intensity shall be attenuated by choosing relevant materials like mild steel, stainless steel, lead, or low ‘z’ materials in case of beta emission etc., So whatever be the shielding material, the thickness of the material holds a pivotal role in reduction of dose. Concrete is used as a more common building material in order to have an in situ protection rather than the material design and shielding. A software tool is developed (J-shielder) to find out the thickness of the shielding material to achieve the desired attenuation. The paper reveals that the numerical simulations performed to find out the attenuation of gamma rays while passing through ordinary concrete using the software. The execution of this application software is found useful in determining at the shield thickness of ordinary concrete for radionuclides of different strength and energies. Key words: Ionizing radiation, shielding, attenuation, numerical simulation.
{"title":"Investigation of attenuation parameters for concrete shielding using simulations through iterative approach and measurement","authors":"Vidhya Sivasailanathan, Prabhat Kumar, S. Sagadevan","doi":"10.5897/SRE2017.6497","DOIUrl":"https://doi.org/10.5897/SRE2017.6497","url":null,"abstract":"The intensity of the ionizing radiations can be reduced by allowing them to pass through certain materials and such external materials are known as shields. The shielding material is often chosen based on the type and intensity of the radiation. The radionuclides of standard radioactive sources for calibration purpose or therapeutic use, the irradiated components that produce ionizing radiation of high intensity shall be attenuated by choosing relevant materials like mild steel, stainless steel, lead, or low ‘z’ materials in case of beta emission etc., So whatever be the shielding material, the thickness of the material holds a pivotal role in reduction of dose. Concrete is used as a more common building material in order to have an in situ protection rather than the material design and shielding. A software tool is developed (J-shielder) to find out the thickness of the shielding material to achieve the desired attenuation. The paper reveals that the numerical simulations performed to find out the attenuation of gamma rays while passing through ordinary concrete using the software. The execution of this application software is found useful in determining at the shield thickness of ordinary concrete for radionuclides of different strength and energies. \u0000 \u0000 \u0000 \u0000 Key words: Ionizing radiation, shielding, attenuation, numerical simulation.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"69-76"},"PeriodicalIF":0.0,"publicationDate":"2017-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2017.6497","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43003111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Basaid, C. Aribi, J. Kari, A. Benmounah, B. Safi
This paper presents the effect of matrix type on creep behavior at 80% loads of ultimate tensile strength of two laminated composites at different fiber and matrix system. For this, two types of laminated composites were manufactured based on two types of fibers (carbon fabric and glass fabric) with different matrix systems EPOCAST 50-A1 (EP50-A), Epoxy STR (STR) and Epoxy INJ812 (INJ). The tensile and creep behavior of each laminated composite was studied in the same test conditions. A microstructural study was also investigated by SEM-microscopy on the morphology of composite specimens after creep rupture failures at 80% of applied load. The obtained results showed clearly the influence of matrix type used on the tensile and creep behavior of studied composites. Indeed, it was noted that no creep rupture failures were observed in short-term (less than 4 h) for INJ/Carbon composite at tensile creep tests at 80% loads of ultimate tensile strength. At the same ultimate tensile strength, EP50/Carbon composite showed a best creep behavior up to 30 h and had a creep modulus higher than other laminated composites. The observation of rupture facets of all composite samples showed clearly that the rupture will take place in the direction of loading, creating voids at the interface resin/fiber. These are observed based on the nature of the matrix used. Key words: Epoxy, aliphatic amine, cross-linked, carbon fabric, glass fabric, creep test, cyclic tensile test.
{"title":"A comparative study of the creep behavior of laminated composites: Effect of type of fiber and matrix","authors":"D. Basaid, C. Aribi, J. Kari, A. Benmounah, B. Safi","doi":"10.5897/SRE2017.6492","DOIUrl":"https://doi.org/10.5897/SRE2017.6492","url":null,"abstract":"This paper presents the effect of matrix type on creep behavior at 80% loads of ultimate tensile strength of two laminated composites at different fiber and matrix system. For this, two types of laminated composites were manufactured based on two types of fibers (carbon fabric and glass fabric) with different matrix systems EPOCAST 50-A1 (EP50-A), Epoxy STR (STR) and Epoxy INJ812 (INJ). The tensile and creep behavior of each laminated composite was studied in the same test conditions. A microstructural study was also investigated by SEM-microscopy on the morphology of composite specimens after creep rupture failures at 80% of applied load. The obtained results showed clearly the influence of matrix type used on the tensile and creep behavior of studied composites. Indeed, it was noted that no creep rupture failures were observed in short-term (less than 4 h) for INJ/Carbon composite at tensile creep tests at 80% loads of ultimate tensile strength. At the same ultimate tensile strength, EP50/Carbon composite showed a best creep behavior up to 30 h and had a creep modulus higher than other laminated composites. The observation of rupture facets of all composite samples showed clearly that the rupture will take place in the direction of loading, creating voids at the interface resin/fiber. These are observed based on the nature of the matrix used. \u0000 \u0000 \u0000 \u0000 Key words: Epoxy, aliphatic amine, cross-linked, carbon fabric, glass fabric, creep test, cyclic tensile test.","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"59-68"},"PeriodicalIF":0.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2017.6492","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48619835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The incidence of diseases is on the surge as exemplified by the recent occurrence in West Africa of Ebola Virus (EBOV) and increase of Zika Virus in Brazil. These pathogens have evolved strategies to evade the human immune system and thus continue to be globally important human pathogens. Bioengineering capabilities are on the increase with rapid advances in synthetic biology and allied technologies (nanobiotechnology, nanotechnology, OMICs technologies, and genetic engineering) which bring potential future prospects in combating disease causing agents using the knowledge of pathogenesis of these disease causing agents. This paper specifically takes a forward looking approach in proposing a potential future use of bioengineering technologies to combat disease causing pathogens as exemplified by Human Immunodeficiency Virus (HIV), Ebola Virus (EBOV), and Mycobacterium tuberculosis through the design, building and testing of synthetic bioengineered minimal genomes with pathogen neutralising capabilities and pathogen detection sensitivity similar to whole cell based biosensors. Key words: Tuberculosis, Ebola, AIDS, synthetic biology, omics, biosensors, nanotechnology
{"title":"Glance at potential future combating of diseases:Bioengineered antimicrobial organisms","authors":"Chenjerayi Kashangura","doi":"10.5897/SRE2016.6475","DOIUrl":"https://doi.org/10.5897/SRE2016.6475","url":null,"abstract":"The incidence of diseases is on the surge as exemplified by the recent occurrence in West Africa of Ebola Virus (EBOV) and increase of Zika Virus in Brazil. These pathogens have evolved strategies to evade the human immune system and thus continue to be globally important human pathogens. Bioengineering capabilities are on the increase with rapid advances in synthetic biology and allied technologies (nanobiotechnology, nanotechnology, OMICs technologies, and genetic engineering) which bring potential future prospects in combating disease causing agents using the knowledge of pathogenesis of these disease causing agents. This paper specifically takes a forward looking approach in proposing a potential future use of bioengineering technologies to combat disease causing pathogens as exemplified by Human Immunodeficiency Virus (HIV), Ebola Virus (EBOV), and Mycobacterium tuberculosis through the design, building and testing of synthetic bioengineered minimal genomes with pathogen neutralising capabilities and pathogen detection sensitivity similar to whole cell based biosensors. \u0000 \u0000 Key words: Tuberculosis, Ebola, AIDS, synthetic biology, omics, biosensors, nanotechnology","PeriodicalId":21603,"journal":{"name":"Scientific Research and Essays","volume":"12 1","pages":"51-58"},"PeriodicalIF":0.0,"publicationDate":"2017-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5897/SRE2016.6475","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45408257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：