The study investigated the application of radiofrequency(RF)-sputtered TiO2 coatings at various temperatures to enhance the hydrophobicity and corrosion resistance of Al6061 alloy.The research aimed to establish a cor...The study investigated the application of radiofrequency(RF)-sputtered TiO2 coatings at various temperatures to enhance the hydrophobicity and corrosion resistance of Al6061 alloy.The research aimed to establish a correlation between the coating process and the resulting surface properties.Surface roughness and wettability were quantified with a surface profilometer and goniometer.Additionally,chemical boiling and salt spray corrosion tests were conducted to evaluate any topographical changes during these procedures.The analysis further involved the use of field-emission scanning electron microscopy(FESEM),energy-dispersive spectroscopy(EDS),and X-ray diffraction(XRD)techniques to characterize the deposited coatings.The findings indicated that the TiO2 coating applied at 500℃exhibited the highest water contact angle and superior corrosion resistance compared to other temperatures.Surface characterization confirmed that this specific TiO_(2) coating at 500℃ effectively delays corrosion due to its hydrophobic behavior,making it durable for industrial applications.展开更多
Food is one of the biggest industries in developed and underdeveloped countries. Supply chain sustainability is essential in established and emerging economies because of the rising acceptance of cost-based outsourcin...Food is one of the biggest industries in developed and underdeveloped countries. Supply chain sustainability is essential in established and emerging economies because of the rising acceptance of cost-based outsourcing and the growing technological, social, and environmental concerns. The food business faces serious sustainability and growth challenges in developing countries. A comprehensive analysis of the critical success factors (CSFs) influencing the performance outcome and the sustainable supply chain management (SSCM) process. A theoretical framework is established to explain how they are used to examine the organizational aspect of the food supply chain life cycle analysis. This study examined the CSFs and revealed the relationships between them using a methodology that included a review of literature, interpretative structural modeling (ISM), and cross-impact matrix multiplication applied in classification (MICMAC) tool analysis of soil liquefaction factors. The findings of this research demonstrate that the quality and safety of food are important factors and have a direct effect on other factors. To make sustainable food supply chain management more adequate, legislators, managers, and experts need to pay attention to this factor. In this work. It also shows that companies aiming to create a sustainable business model must make sustainability a fundamental tenet of their organization. Practitioners and managers may devise effective long-term plans for establishing a sustainable food supply chain utilizing the recommended methodology.展开更多
Solar and wind energy are two of the most viable and sustainable sources of energy due to the tendency of renewal. The power generating supplies in Nigeria appear unreliable, rapidly diminishing and expensive. Researc...Solar and wind energy are two of the most viable and sustainable sources of energy due to the tendency of renewal. The power generating supplies in Nigeria appear unreliable, rapidly diminishing and expensive. Researches are sparse on operating both energy sources alongside fossil fuel for power generation in order to take advantage of their complementary characters. The aim of this study is to explore renewable sources combined with non-renewable source to generate electricity with the objective of establishing an optimal design for a hybrid solar-wind-diesel energy plant that minimizes cost. The capacity factor of the standalone system was determined for the study area. The cost of energy for the hybrid optimal mix was determined. Levelised cost of energy was also used to determine the cost of energy for standalone power system. The result shows that the energy generated 200 MW hybrid system is 392 GWh with a cost of energy of $0.24/kWh (47.8/kWh). The energy produced can power 39,200 homes in a year. The optimisation shows that the number of solar system, wind and diesel are 699, 1 and 300 respectively. The cost of energy for the standalone system was $0.06/kWh, $0.08/kWh and $0.27/kWh for wind, solar and diesel system. The capacity factor was 56%, 21% and 80% for wind, solar and diesel system. There is a reduction in the amount of greenhouse gases released to the environment alongside with cost of energy generation. Hybrid power generation system is good and effective solution for power generation than conventional energy resources.展开更多
Nanotechnology has extensive application as nanomedicine in the medical field.Some nanoparticles have possible applications in novel diagnostic instruments,imagery and methodologies,targeted medicinal products,pharmac...Nanotechnology has extensive application as nanomedicine in the medical field.Some nanoparticles have possible applications in novel diagnostic instruments,imagery and methodologies,targeted medicinal products,pharmaceutical products,biomedical implants,and tissue engineering.Today treatments of high toxicity can be administered with improved safety using nanotechnology,such as chemotherapeutic cancer drugs.Further,wearable gadgets can detect crucial changes in vital signs,cancer cell conditions,and infections that are genuinely happening in the body.We anticipate these technologies to provide doctors with considerably much better direct access to critical data on the reasons for changes in the signs of life or illness because of the technological presence at the source of the problem.Biomedicine can be utilised for therapies with predictive analytics and artificial intelligence.For carrying out this study,relevant papers on Nanotechnology in the medical field from Scopus,Google scholar,ResearchGate,and other research platforms are identified and studied.The study discusses different types of Nanoparticles used in the medical field.This paper discusses nanotechnology applications in the medical field.The class,features,and characteristics of Nanotechnology for medicine are also briefed.Scientists,governments,civil society organisations,and the general public will need to collaborate across sectors to assess the significance of nanotechnology and guide its advancement in various fields.The current research includes several possible Nanotechnology uses in the medical field.As a result,the study provides a brief and well-organised report on nanotechnology that should be valuable to researchers,engineers,and scientists for future research projects.展开更多
The steam turbine is a prime mover that converts kinetic energy in steam into rotational mechanical energy through the impact or reaction of the steam against the blades. The aim of this study is to design a steam tur...The steam turbine is a prime mover that converts kinetic energy in steam into rotational mechanical energy through the impact or reaction of the steam against the blades. The aim of this study is to design a steam turbine for a small scale steam power plant with target of producing electricity. The turbine is driven by the heat energy from palm kernel shells as a renewable energy source obtained at a lower or no cost. The study was concentrated on design of turbine elements and its validation using computer packages. Specifically, the microturbine design was limited to design, modeling, simulation and analysis of the rotor, blades and nozzle under the palm kernel shell as fuel for the micro power plant. In blade design, stress failures, efficiency and blade angle parameters were considered. In casing volume design, the overall heat transfer and mean temperature, and different concepts were applied. The thermal distribution on stator and rotor was considered in order to determine its level of tolerance. The design software packages used for design validation were Solidworks and Comsol Multiphysics for analysis. Simulation results showed that the designed steam turbine can adequately tolerate change in stress/load, torsion/compression, temperature and speeds.展开更多
Unmanned Aerial Vehicles(UAVs)or drones introduced for military applications are gaining popularity in several other fields as well such as security and surveillance,due to their ability to perform repetitive and tedi...Unmanned Aerial Vehicles(UAVs)or drones introduced for military applications are gaining popularity in several other fields as well such as security and surveillance,due to their ability to perform repetitive and tedious tasks in hazardous environments.Their increased demand created the requirement for enabling the UAVs to traverse independently through the Three Dimensional(3D)flight environment consisting of various obstacles which have been efficiently addressed by metaheuristics in past literature.However,not a single optimization algorithms can solve all kind of optimization problem effectively.Therefore,there is dire need to integrate metaheuristic for general acceptability.To address this issue,in this paper,a novel reinforcement learning controlled Grey Wolf Optimisation-Archimedes Optimisation Algorithm(QGA)has been exhaustively introduced and exhaustively validated firstly on 22 benchmark functions and then,utilized to obtain the optimum flyable path without collision for UAVs in three dimensional environment.The performance of the developed QGA has been compared against the various metaheuristics.The simulation experimental results reveal that the QGA algorithm acquire a feasible and effective flyable path more efficiently in complicated environment.展开更多
Developing a sustainable energy model is imperative considering the current trend towards decarbonizing sectors worldwide.For this purpose,Venezuela was used as a reference to propose an energy model focused on taking...Developing a sustainable energy model is imperative considering the current trend towards decarbonizing sectors worldwide.For this purpose,Venezuela was used as a reference to propose an energy model focused on taking advantage of plant photosynthesis through microbial-vegetable fuel cells together with an agro-photovoltaic system to enhance energy and agricultural production.Energy production from the cells was estimated using an average power density of 264 mW/m^(2) over 4%of the areas destined for crops in the entire Venezuelan region,obtaining an annual production of 19.889 GWh/year.In contrast,the energy production of the agro-photovoltaic system was modelled using PVsyst software on 50%of the area used for the cells distributed throughout the states of Anzoátegui,Guárico,Monagas and Portuguesa according to their meteorological conditions,solar irradiation and agricultural activity,resulting in 3703417 GWh/year.The resulting whole system proved to be able to cover>10 times the installed electricity generation capacity at a national level and,together with the tremendous scalability of the microbial fuel cells,it shows that Venezuela has a high potential for the production and distribution of clean energy.展开更多
In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inhere...In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication (MQL) has been suggested since a decade ago as a means of addressing the issues of environmental intru- siveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.展开更多
The effect of Cu content on the microstructure,grain orientation and mechanical properties of Sn-xCu(x=0-4.0 wt.%)lead-free solder was studied.Results showed that added Cu induced the formation of intermetallic phases...The effect of Cu content on the microstructure,grain orientation and mechanical properties of Sn-xCu(x=0-4.0 wt.%)lead-free solder was studied.Results showed that added Cu induced the formation of intermetallic phases.Only theη-Cu;Sn;andε-Cu;Sn phases were present in theβ-Sn matrix.For all contents,the strongly preferred orientation of theβ-Sn phase was formed on the{001}plane.In Sn doped with 1.0 wt.%Cu,theη-Cu;Sn;phase exhibited the preferred orientation of{0001}plane,whereas doping with 3.0 or 4.0 wt.%Cu transformed the preferred orientation to the{010}plane.In addition,only the{0001}and{■}planes were present in theε-Cu;Sn phase.The high Cu contents contributed to an increased number of low-angle boundaries,high residual strain,tensile strength and microhardness.展开更多
This paper deals with the study of mechanical properties of Potassium Titanate Whisker (PTW) reinforced epoxy based Polymer Matrix Composites (PMCs). Epoxy composites filled with PTW in various content of 0-20 wt% wer...This paper deals with the study of mechanical properties of Potassium Titanate Whisker (PTW) reinforced epoxy based Polymer Matrix Composites (PMCs). Epoxy composites filled with PTW in various content of 0-20 wt% were prepared using the casting technique. Data on neat epoxy is also included for comparison. All tests were conducted at room temperature and as per ASTM standards. It was observed that inclusion of PTW affected most of the mechanical properties of neat epoxy. Density, hardness and heat deflection temperature of neat epoxy were found to increase with the PTW content. However tensile and flexural properties of the developed composites exhibited a varying trend with respect to PTW content. Epoxy filled with 10 wt% PTW showed good improvement in tensile strength and flexural strength of neat epoxy. It was observed that PTW is not beneficial in improving the impact strength of neat epoxy. Composites with 20 wt% PTW exhibited least impact strength. This paper also highlights the possible reasons for variation in the mechanical properties of developed polymer composites.展开更多
A hybrid joint with a satisfactory mixture of pure magnesium and polypropylene(PP)was achieved via friction stir joining(FSW)in a lap-joint configuration.The tool rotational and travel speeds used in this work were 50...A hybrid joint with a satisfactory mixture of pure magnesium and polypropylene(PP)was achieved via friction stir joining(FSW)in a lap-joint configuration.The tool rotational and travel speeds used in this work were 500–700 r/min and 50–100 mm/min,respectively.The mechanical properties and microstructural analysis of the resultant hybrid Mg/PP joint were examined.The results show that the maximum tensile shear strength(22.5 MPa)of the joint was attained at 700 r/min and 75 mm/min due to the optimum percentage fraction of mechanical interlocking(48%)and the presence of magnesium oxide.The interfacial joint center exhibits the maximum microhardness values because of the presence of refined and intertwined Mg fragments and density dislocations in the matrix of the PP.The joint failed via two different modes:interfacial line and weld zone fractures,respectively.展开更多
This paper studies the friction stir spot welding of AA2024-T3/AA7075-T6 Al alloys in the ambient and underwater environments by clarifying the nugget features,microstructure,fracture and mechanical properties of the ...This paper studies the friction stir spot welding of AA2024-T3/AA7075-T6 Al alloys in the ambient and underwater environments by clarifying the nugget features,microstructure,fracture and mechanical properties of the joints.The results show that the water-cooling medium exhibits a significant heat absorption capacity in the AA2024-T3/AA7075-T6 welded joint.Nugget features such as stir zone width,circular imprints,average grain sizes,and angular inter-material hooking are reduced by the watercooling effect in the joints.Narrower whitish(intercalated structures)bands are formed in the underwater joints while Mg2Si and Al2CuMg precipitates are formed in the ambient and the underwater welded joints respectively.An increase in tool rotational speed(600e1400 rpm)and plunge depth(0.1 e0.5 mm)increases the tensile-shear force of the welded AA2024-T3/AA7075-T6 joints in both the ambient and underwater environments.The maximum tensile-shear forces of 5900 N and 6700 N were obtained in the ambient and the underwater welds respectively.展开更多
Ti Ni shape memory alloys(SMAs) have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditiona...Ti Ni shape memory alloys(SMAs) have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditional machining of SMAs is quite complex due to these properties. Hence, the wire electric discharge machining(WEDM) characteristics of Ti Ni SMA was studied. The experiments were planned as per L27 orthogonal array to minimize the experiments, each experiment was performed under different conditions of pulse duration, pulse off time, servo voltage, flushing pressure and wire speed. A multi-response optimization method using Taguchi design with utility concept has been proposed for simultaneous optimization. The analysis of means(ANOM) and analysis of variance(ANOVA) on signal to noise(S/N) ratio were performed for determining the optimal parameter levels. Taguchi analysis reveals that a combination of 1 μs pulse duration, 3.8 μs pulse off time, 40 V servo voltage, 1.8×105 Pa flushing pressure and 8 m/min wire speed is beneficial for simultaneously maximizing the material removal rate(MRR) and minimizing the surface roughness. The optimization results of WEDM of Ti Ni SMA also indicate that pulse duration significantly affects the material removal rate and surface roughness. The discharged craters, micro cracks and recast layer were observed on the machined surface at large pulse duration.展开更多
Life Cycle Assessment (LCA) is an analytical tool used for the environmental optimization of products and services within the entirety of its life cycle. ISO 14040 recommends use of the technique in numerous areas of ...Life Cycle Assessment (LCA) is an analytical tool used for the environmental optimization of products and services within the entirety of its life cycle. ISO 14040 recommends use of the technique in numerous areas of environmental management such as in designing for the environment, eco-labelling, environmental communications and the assessment of the effects of environmental activities. Despite being theoretically feasible, certain applications of the ecological assessment of a life cycle such as the possibility of identification and evaluation of environmental aspects with the use of LCA are, in practice, still new to many environmental managers. With its strong points, the technique seems to be a valuable tool, especially in the context of apparent concepts of Product-Oriented Environmental Management Systems (POEMS). In order to verify the hypothesis, the author decided to verify the level of use of LCA in the area of identification and assessment of environmental aspects in selected organizations. Therefore, questionnaire interviews were conducted with representatives of selected Polish and Swedish enterprises who, at the time of the interview, had certified environmental management systems. The organizations were analyzed with respect to applied methods and techniques used for identification and assessment of environmental aspects as well as the degree of use of LCA both in this respect and in other areas of environmental management. This paper will present the results of this research and conclusions.展开更多
This paper reports the dry sliding wear behavior & Brinell hardness test of AA 5083 aluminium reinforced with SiC particles fabricated by stir casting technique. Different volume fraction of SiC particles (3, 5 an...This paper reports the dry sliding wear behavior & Brinell hardness test of AA 5083 aluminium reinforced with SiC particles fabricated by stir casting technique. Different volume fraction of SiC particles (3, 5 and 7 wt%) were used for synthesis. The wear test has been conducted on pin-on-disc testing machine to examine the wear behaviour of the aluminium alloy and its composites. An attempt has been made to study the influence of wear parameters like applied load, sliding speed, sliding distance and percentage of reinforcement on the dry sliding wear of metal matrix composites (MMCs). A plan of experiments, based on the techniques of Taguchi, was performed to acquire data in controlled way. An orthogonal array of L9 (34) and signal to noise ratios as smaller the better was selected. Analysis of variance (ANOVA) was employed to investigate the influence of wear parameter on pin of aluminium MMCs. The correlation was obtained by multiple general regressions model. Finally, conformation tests were done to make a comparison between the experimental results foreseen from the mentioned correlation.展开更多
In the modern era of manufacturing, it is important to optimize every design parameter in product development stage to reduce cost, material usage and to achieve the desired efficacy level. There are various models wh...In the modern era of manufacturing, it is important to optimize every design parameter in product development stage to reduce cost, material usage and to achieve the desired efficacy level. There are various models which serve those purposes, for instance, Design of Experiment (DoE) is used to check the parameters after adopting optimization tactics which results in reduced cost or saving operating time. In this regard, this research aims to construct a DoE model on a portable workstation to optimize its design parameters. The methodology of DOE would be a 2 level 3 factors full factorial DOE which is conducted to determine the optimal value for three design parameters (factors) which are material density, the length of the table and the length of the table stand in terms of the response which is the required time of fold ability function of the portable workstation. Based upon the evaluated interactions between the parameters, the optimized parameters are chosen for responses. Here, the resultant design parameters are at their lowest level, so the goal of time efficiency in fold ability function is achieved. This similar sort of DoE can be implemented in the furniture and other manufacturing industries who wish to optimize their material usage as well as increase efficiency and reduce cycle time.展开更多
The three-body abrasive wear behaviour of carbon fabric reinforced epoxy (C-E) composites has been evaluated by the addition of graphite (G) particles as a secondary reinforcement. Three-body abrasive wear test were c...The three-body abrasive wear behaviour of carbon fabric reinforced epoxy (C-E) composites has been evaluated by the addition of graphite (G) particles as a secondary reinforcement. Three-body abrasive wear test were conducted using dry sand rubber wheel abrasion tester as per ASTM G-65 with three process parameters load, abrading distance and filler content. To assess the abrasive wear behaviour of particulate filled C-E composites satisfying multiple performance measure, grey-based Taguchi approach has been adopted. The experiments were designed according to Taguchi’s orthogonal array (L?27). The grey relational analysis was applied to convert a multi response process optimization to a single response. Using analysis of variance, significant contributions of process parameters have been determined. The results indicate that the addition of graphite particles into C-E composite increased the wear resistance considerably. It was observed that highest wear resistance of C-E composite was achieved with incorporation of 10 wt. % of graphite filler. Results indicate that the filler content and grit size of abrasive paper were found to be the most significant factor which has influence on the abrasive wear of C-E composite. The worn surface features were examined through scanning electron microscope to probe the wear mechanism.展开更多
The study focused on experimental and classical data to establish some mechanical properties for optimum design of new polypropylene components to serve under creep environment. The creep studies recorded stress limit...The study focused on experimental and classical data to establish some mechanical properties for optimum design of new polypropylene components to serve under creep environment. The creep studies recorded stress limits that never exceeded 24.19MPa and maximum creep modulus that never exceeded 1.49GPa as against the predictions of classical equations that gave 2.0GPa for PPC0 and 2.46GPa for PPC2 at ambient conditions. The shear modulus and shear strength of the PPC0 and the PPC2 are predicted as 0.75GPa and 120MPa respectively and 0.92GPa and 150MPa respectively while the yield strengths found to be about 13.19MPa and 13.20MPa respectively for PPC0 and PPC2 at elastic strains 0.008 and 0.009 respectively. Further found are that as the material deforms the stiffness or modulus decrease, at low strains there is an elastic region, as temperature and applied stress increase the material becomes more flexible characterized with reduction in moduli. Plastic deformation at strains above 0.01 resulted to strain- hardening or strain-strengthening that manifested as the increasing area ratios and associated creep cold work. Also established by this study is a computational model for evaluating the elastic modulus of polypropylene matrix based material as expressed in equation (6). Both the Halphin-Tsai and the Birintrup equations for elastic modulus of unidirectional fibre composites were confirmed to be appropriate for prediction of elastic modulus of nanofiller composites with polymer matrix.展开更多
This paper examines the behavior of low carbon steels subjected to a frequency thermal cycling test. A compositional analysis was performed to ascertain the percentage of carbon in the asreceived materials. The specim...This paper examines the behavior of low carbon steels subjected to a frequency thermal cycling test. A compositional analysis was performed to ascertain the percentage of carbon in the asreceived materials. The specimens were machined to a precise gauge length and diameter and exposed to various cycles of heat at each temperature. A fatigue test was also performed with the use of Avery Dennison and bending stress was obtained using the curve supplied with the machine. The results from the machine were converted to Mega Pascal (MPa) and the values used to plot S-N curves and fatigue resistance for the specimens at various cycles and different temperatures were established.展开更多
This paper is about the use of power law model to fit experimental creep data of PP reinforced with calcium carbonate nanofiller at 10% optimum volume fraction with a view to characterizing the new material (PPC2) par...This paper is about the use of power law model to fit experimental creep data of PP reinforced with calcium carbonate nanofiller at 10% optimum volume fraction with a view to characterizing the new material (PPC2) parametrically. The creep parameters were evaluated for neat (PPC0) and reinforced PP (PPC2) to establish the influence of reinforcement on the creep variables like creep rate and creep activation energy. The coefficient parameter A estimated within the stress level range 13.08MPa-22.88MPa has the range 0.0165-0.0651 while the exponent parameter n has 0.299-0.370. The creep stress coefficient K and exponent m has the respective values 161.495 and 0.3288 for PPC0 and 1881.4965 and 0.5448 for PPC2. The value of the parameter p similar to Larson-Miller has the value 4014.1871. Two creep function models used found that PPC0 has higher activation energy with value 9.3642E-20 J/mol for the stress 13.08MPa and PPC2 has values for the stresses 13.08MPa, 19.61MPa and 22.88MPa as 5.55998E- 20J/mol,5.4573E-20J/mol and 4.845E-20J/mol respectively. Of the two master curves produced, that following Larson-Miller parameter is recommended as the relationship between lnσ and parameter f(σ) is relatively linear and will give better results than the curve assumed to follow Sherby-Dorn that will give average result.展开更多
文摘The study investigated the application of radiofrequency(RF)-sputtered TiO2 coatings at various temperatures to enhance the hydrophobicity and corrosion resistance of Al6061 alloy.The research aimed to establish a correlation between the coating process and the resulting surface properties.Surface roughness and wettability were quantified with a surface profilometer and goniometer.Additionally,chemical boiling and salt spray corrosion tests were conducted to evaluate any topographical changes during these procedures.The analysis further involved the use of field-emission scanning electron microscopy(FESEM),energy-dispersive spectroscopy(EDS),and X-ray diffraction(XRD)techniques to characterize the deposited coatings.The findings indicated that the TiO2 coating applied at 500℃exhibited the highest water contact angle and superior corrosion resistance compared to other temperatures.Surface characterization confirmed that this specific TiO_(2) coating at 500℃ effectively delays corrosion due to its hydrophobic behavior,making it durable for industrial applications.
文摘Food is one of the biggest industries in developed and underdeveloped countries. Supply chain sustainability is essential in established and emerging economies because of the rising acceptance of cost-based outsourcing and the growing technological, social, and environmental concerns. The food business faces serious sustainability and growth challenges in developing countries. A comprehensive analysis of the critical success factors (CSFs) influencing the performance outcome and the sustainable supply chain management (SSCM) process. A theoretical framework is established to explain how they are used to examine the organizational aspect of the food supply chain life cycle analysis. This study examined the CSFs and revealed the relationships between them using a methodology that included a review of literature, interpretative structural modeling (ISM), and cross-impact matrix multiplication applied in classification (MICMAC) tool analysis of soil liquefaction factors. The findings of this research demonstrate that the quality and safety of food are important factors and have a direct effect on other factors. To make sustainable food supply chain management more adequate, legislators, managers, and experts need to pay attention to this factor. In this work. It also shows that companies aiming to create a sustainable business model must make sustainability a fundamental tenet of their organization. Practitioners and managers may devise effective long-term plans for establishing a sustainable food supply chain utilizing the recommended methodology.
文摘Solar and wind energy are two of the most viable and sustainable sources of energy due to the tendency of renewal. The power generating supplies in Nigeria appear unreliable, rapidly diminishing and expensive. Researches are sparse on operating both energy sources alongside fossil fuel for power generation in order to take advantage of their complementary characters. The aim of this study is to explore renewable sources combined with non-renewable source to generate electricity with the objective of establishing an optimal design for a hybrid solar-wind-diesel energy plant that minimizes cost. The capacity factor of the standalone system was determined for the study area. The cost of energy for the hybrid optimal mix was determined. Levelised cost of energy was also used to determine the cost of energy for standalone power system. The result shows that the energy generated 200 MW hybrid system is 392 GWh with a cost of energy of $0.24/kWh (47.8/kWh). The energy produced can power 39,200 homes in a year. The optimisation shows that the number of solar system, wind and diesel are 699, 1 and 300 respectively. The cost of energy for the standalone system was $0.06/kWh, $0.08/kWh and $0.27/kWh for wind, solar and diesel system. The capacity factor was 56%, 21% and 80% for wind, solar and diesel system. There is a reduction in the amount of greenhouse gases released to the environment alongside with cost of energy generation. Hybrid power generation system is good and effective solution for power generation than conventional energy resources.
文摘Nanotechnology has extensive application as nanomedicine in the medical field.Some nanoparticles have possible applications in novel diagnostic instruments,imagery and methodologies,targeted medicinal products,pharmaceutical products,biomedical implants,and tissue engineering.Today treatments of high toxicity can be administered with improved safety using nanotechnology,such as chemotherapeutic cancer drugs.Further,wearable gadgets can detect crucial changes in vital signs,cancer cell conditions,and infections that are genuinely happening in the body.We anticipate these technologies to provide doctors with considerably much better direct access to critical data on the reasons for changes in the signs of life or illness because of the technological presence at the source of the problem.Biomedicine can be utilised for therapies with predictive analytics and artificial intelligence.For carrying out this study,relevant papers on Nanotechnology in the medical field from Scopus,Google scholar,ResearchGate,and other research platforms are identified and studied.The study discusses different types of Nanoparticles used in the medical field.This paper discusses nanotechnology applications in the medical field.The class,features,and characteristics of Nanotechnology for medicine are also briefed.Scientists,governments,civil society organisations,and the general public will need to collaborate across sectors to assess the significance of nanotechnology and guide its advancement in various fields.The current research includes several possible Nanotechnology uses in the medical field.As a result,the study provides a brief and well-organised report on nanotechnology that should be valuable to researchers,engineers,and scientists for future research projects.
文摘The steam turbine is a prime mover that converts kinetic energy in steam into rotational mechanical energy through the impact or reaction of the steam against the blades. The aim of this study is to design a steam turbine for a small scale steam power plant with target of producing electricity. The turbine is driven by the heat energy from palm kernel shells as a renewable energy source obtained at a lower or no cost. The study was concentrated on design of turbine elements and its validation using computer packages. Specifically, the microturbine design was limited to design, modeling, simulation and analysis of the rotor, blades and nozzle under the palm kernel shell as fuel for the micro power plant. In blade design, stress failures, efficiency and blade angle parameters were considered. In casing volume design, the overall heat transfer and mean temperature, and different concepts were applied. The thermal distribution on stator and rotor was considered in order to determine its level of tolerance. The design software packages used for design validation were Solidworks and Comsol Multiphysics for analysis. Simulation results showed that the designed steam turbine can adequately tolerate change in stress/load, torsion/compression, temperature and speeds.
基金funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2022R66),Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia.
文摘Unmanned Aerial Vehicles(UAVs)or drones introduced for military applications are gaining popularity in several other fields as well such as security and surveillance,due to their ability to perform repetitive and tedious tasks in hazardous environments.Their increased demand created the requirement for enabling the UAVs to traverse independently through the Three Dimensional(3D)flight environment consisting of various obstacles which have been efficiently addressed by metaheuristics in past literature.However,not a single optimization algorithms can solve all kind of optimization problem effectively.Therefore,there is dire need to integrate metaheuristic for general acceptability.To address this issue,in this paper,a novel reinforcement learning controlled Grey Wolf Optimisation-Archimedes Optimisation Algorithm(QGA)has been exhaustively introduced and exhaustively validated firstly on 22 benchmark functions and then,utilized to obtain the optimum flyable path without collision for UAVs in three dimensional environment.The performance of the developed QGA has been compared against the various metaheuristics.The simulation experimental results reveal that the QGA algorithm acquire a feasible and effective flyable path more efficiently in complicated environment.
文摘Developing a sustainable energy model is imperative considering the current trend towards decarbonizing sectors worldwide.For this purpose,Venezuela was used as a reference to propose an energy model focused on taking advantage of plant photosynthesis through microbial-vegetable fuel cells together with an agro-photovoltaic system to enhance energy and agricultural production.Energy production from the cells was estimated using an average power density of 264 mW/m^(2) over 4%of the areas destined for crops in the entire Venezuelan region,obtaining an annual production of 19.889 GWh/year.In contrast,the energy production of the agro-photovoltaic system was modelled using PVsyst software on 50%of the area used for the cells distributed throughout the states of Anzoátegui,Guárico,Monagas and Portuguesa according to their meteorological conditions,solar irradiation and agricultural activity,resulting in 3703417 GWh/year.The resulting whole system proved to be able to cover>10 times the installed electricity generation capacity at a national level and,together with the tremendous scalability of the microbial fuel cells,it shows that Venezuela has a high potential for the production and distribution of clean energy.
基金Project (No. DEARS/CASR/R-01/2001/D-934 (30)) supported by Directorate of Advisory Extension and Research Services (DAERS), Committee for Advanced Studies & Research (CASR), BUET, Dhaka, Bangladesh
文摘In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication (MQL) has been suggested since a decade ago as a means of addressing the issues of environmental intru- siveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.
基金Rajamangala University of Technology Rattanakosin and School of Engineering,King Mongkut’s Institute of Technology Ladkrabang for the laboratory support of this research。
文摘The effect of Cu content on the microstructure,grain orientation and mechanical properties of Sn-xCu(x=0-4.0 wt.%)lead-free solder was studied.Results showed that added Cu induced the formation of intermetallic phases.Only theη-Cu;Sn;andε-Cu;Sn phases were present in theβ-Sn matrix.For all contents,the strongly preferred orientation of theβ-Sn phase was formed on the{001}plane.In Sn doped with 1.0 wt.%Cu,theη-Cu;Sn;phase exhibited the preferred orientation of{0001}plane,whereas doping with 3.0 or 4.0 wt.%Cu transformed the preferred orientation to the{010}plane.In addition,only the{0001}and{■}planes were present in theε-Cu;Sn phase.The high Cu contents contributed to an increased number of low-angle boundaries,high residual strain,tensile strength and microhardness.
文摘This paper deals with the study of mechanical properties of Potassium Titanate Whisker (PTW) reinforced epoxy based Polymer Matrix Composites (PMCs). Epoxy composites filled with PTW in various content of 0-20 wt% were prepared using the casting technique. Data on neat epoxy is also included for comparison. All tests were conducted at room temperature and as per ASTM standards. It was observed that inclusion of PTW affected most of the mechanical properties of neat epoxy. Density, hardness and heat deflection temperature of neat epoxy were found to increase with the PTW content. However tensile and flexural properties of the developed composites exhibited a varying trend with respect to PTW content. Epoxy filled with 10 wt% PTW showed good improvement in tensile strength and flexural strength of neat epoxy. It was observed that PTW is not beneficial in improving the impact strength of neat epoxy. Composites with 20 wt% PTW exhibited least impact strength. This paper also highlights the possible reasons for variation in the mechanical properties of developed polymer composites.
文摘A hybrid joint with a satisfactory mixture of pure magnesium and polypropylene(PP)was achieved via friction stir joining(FSW)in a lap-joint configuration.The tool rotational and travel speeds used in this work were 500–700 r/min and 50–100 mm/min,respectively.The mechanical properties and microstructural analysis of the resultant hybrid Mg/PP joint were examined.The results show that the maximum tensile shear strength(22.5 MPa)of the joint was attained at 700 r/min and 75 mm/min due to the optimum percentage fraction of mechanical interlocking(48%)and the presence of magnesium oxide.The interfacial joint center exhibits the maximum microhardness values because of the presence of refined and intertwined Mg fragments and density dislocations in the matrix of the PP.The joint failed via two different modes:interfacial line and weld zone fractures,respectively.
基金Scientific Research Fund of Hunan Provincial Education Department(No.15C1240)Innovation platform open fund Project(No.16K080).
文摘This paper studies the friction stir spot welding of AA2024-T3/AA7075-T6 Al alloys in the ambient and underwater environments by clarifying the nugget features,microstructure,fracture and mechanical properties of the joints.The results show that the water-cooling medium exhibits a significant heat absorption capacity in the AA2024-T3/AA7075-T6 welded joint.Nugget features such as stir zone width,circular imprints,average grain sizes,and angular inter-material hooking are reduced by the watercooling effect in the joints.Narrower whitish(intercalated structures)bands are formed in the underwater joints while Mg2Si and Al2CuMg precipitates are formed in the ambient and the underwater welded joints respectively.An increase in tool rotational speed(600e1400 rpm)and plunge depth(0.1 e0.5 mm)increases the tensile-shear force of the welded AA2024-T3/AA7075-T6 joints in both the ambient and underwater environments.The maximum tensile-shear forces of 5900 N and 6700 N were obtained in the ambient and the underwater welds respectively.
文摘Ti Ni shape memory alloys(SMAs) have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditional machining of SMAs is quite complex due to these properties. Hence, the wire electric discharge machining(WEDM) characteristics of Ti Ni SMA was studied. The experiments were planned as per L27 orthogonal array to minimize the experiments, each experiment was performed under different conditions of pulse duration, pulse off time, servo voltage, flushing pressure and wire speed. A multi-response optimization method using Taguchi design with utility concept has been proposed for simultaneous optimization. The analysis of means(ANOM) and analysis of variance(ANOVA) on signal to noise(S/N) ratio were performed for determining the optimal parameter levels. Taguchi analysis reveals that a combination of 1 μs pulse duration, 3.8 μs pulse off time, 40 V servo voltage, 1.8×105 Pa flushing pressure and 8 m/min wire speed is beneficial for simultaneously maximizing the material removal rate(MRR) and minimizing the surface roughness. The optimization results of WEDM of Ti Ni SMA also indicate that pulse duration significantly affects the material removal rate and surface roughness. The discharged craters, micro cracks and recast layer were observed on the machined surface at large pulse duration.
文摘Life Cycle Assessment (LCA) is an analytical tool used for the environmental optimization of products and services within the entirety of its life cycle. ISO 14040 recommends use of the technique in numerous areas of environmental management such as in designing for the environment, eco-labelling, environmental communications and the assessment of the effects of environmental activities. Despite being theoretically feasible, certain applications of the ecological assessment of a life cycle such as the possibility of identification and evaluation of environmental aspects with the use of LCA are, in practice, still new to many environmental managers. With its strong points, the technique seems to be a valuable tool, especially in the context of apparent concepts of Product-Oriented Environmental Management Systems (POEMS). In order to verify the hypothesis, the author decided to verify the level of use of LCA in the area of identification and assessment of environmental aspects in selected organizations. Therefore, questionnaire interviews were conducted with representatives of selected Polish and Swedish enterprises who, at the time of the interview, had certified environmental management systems. The organizations were analyzed with respect to applied methods and techniques used for identification and assessment of environmental aspects as well as the degree of use of LCA both in this respect and in other areas of environmental management. This paper will present the results of this research and conclusions.
文摘This paper reports the dry sliding wear behavior & Brinell hardness test of AA 5083 aluminium reinforced with SiC particles fabricated by stir casting technique. Different volume fraction of SiC particles (3, 5 and 7 wt%) were used for synthesis. The wear test has been conducted on pin-on-disc testing machine to examine the wear behaviour of the aluminium alloy and its composites. An attempt has been made to study the influence of wear parameters like applied load, sliding speed, sliding distance and percentage of reinforcement on the dry sliding wear of metal matrix composites (MMCs). A plan of experiments, based on the techniques of Taguchi, was performed to acquire data in controlled way. An orthogonal array of L9 (34) and signal to noise ratios as smaller the better was selected. Analysis of variance (ANOVA) was employed to investigate the influence of wear parameter on pin of aluminium MMCs. The correlation was obtained by multiple general regressions model. Finally, conformation tests were done to make a comparison between the experimental results foreseen from the mentioned correlation.
文摘In the modern era of manufacturing, it is important to optimize every design parameter in product development stage to reduce cost, material usage and to achieve the desired efficacy level. There are various models which serve those purposes, for instance, Design of Experiment (DoE) is used to check the parameters after adopting optimization tactics which results in reduced cost or saving operating time. In this regard, this research aims to construct a DoE model on a portable workstation to optimize its design parameters. The methodology of DOE would be a 2 level 3 factors full factorial DOE which is conducted to determine the optimal value for three design parameters (factors) which are material density, the length of the table and the length of the table stand in terms of the response which is the required time of fold ability function of the portable workstation. Based upon the evaluated interactions between the parameters, the optimized parameters are chosen for responses. Here, the resultant design parameters are at their lowest level, so the goal of time efficiency in fold ability function is achieved. This similar sort of DoE can be implemented in the furniture and other manufacturing industries who wish to optimize their material usage as well as increase efficiency and reduce cycle time.
文摘The three-body abrasive wear behaviour of carbon fabric reinforced epoxy (C-E) composites has been evaluated by the addition of graphite (G) particles as a secondary reinforcement. Three-body abrasive wear test were conducted using dry sand rubber wheel abrasion tester as per ASTM G-65 with three process parameters load, abrading distance and filler content. To assess the abrasive wear behaviour of particulate filled C-E composites satisfying multiple performance measure, grey-based Taguchi approach has been adopted. The experiments were designed according to Taguchi’s orthogonal array (L?27). The grey relational analysis was applied to convert a multi response process optimization to a single response. Using analysis of variance, significant contributions of process parameters have been determined. The results indicate that the addition of graphite particles into C-E composite increased the wear resistance considerably. It was observed that highest wear resistance of C-E composite was achieved with incorporation of 10 wt. % of graphite filler. Results indicate that the filler content and grit size of abrasive paper were found to be the most significant factor which has influence on the abrasive wear of C-E composite. The worn surface features were examined through scanning electron microscope to probe the wear mechanism.
文摘The study focused on experimental and classical data to establish some mechanical properties for optimum design of new polypropylene components to serve under creep environment. The creep studies recorded stress limits that never exceeded 24.19MPa and maximum creep modulus that never exceeded 1.49GPa as against the predictions of classical equations that gave 2.0GPa for PPC0 and 2.46GPa for PPC2 at ambient conditions. The shear modulus and shear strength of the PPC0 and the PPC2 are predicted as 0.75GPa and 120MPa respectively and 0.92GPa and 150MPa respectively while the yield strengths found to be about 13.19MPa and 13.20MPa respectively for PPC0 and PPC2 at elastic strains 0.008 and 0.009 respectively. Further found are that as the material deforms the stiffness or modulus decrease, at low strains there is an elastic region, as temperature and applied stress increase the material becomes more flexible characterized with reduction in moduli. Plastic deformation at strains above 0.01 resulted to strain- hardening or strain-strengthening that manifested as the increasing area ratios and associated creep cold work. Also established by this study is a computational model for evaluating the elastic modulus of polypropylene matrix based material as expressed in equation (6). Both the Halphin-Tsai and the Birintrup equations for elastic modulus of unidirectional fibre composites were confirmed to be appropriate for prediction of elastic modulus of nanofiller composites with polymer matrix.
文摘This paper examines the behavior of low carbon steels subjected to a frequency thermal cycling test. A compositional analysis was performed to ascertain the percentage of carbon in the asreceived materials. The specimens were machined to a precise gauge length and diameter and exposed to various cycles of heat at each temperature. A fatigue test was also performed with the use of Avery Dennison and bending stress was obtained using the curve supplied with the machine. The results from the machine were converted to Mega Pascal (MPa) and the values used to plot S-N curves and fatigue resistance for the specimens at various cycles and different temperatures were established.
文摘This paper is about the use of power law model to fit experimental creep data of PP reinforced with calcium carbonate nanofiller at 10% optimum volume fraction with a view to characterizing the new material (PPC2) parametrically. The creep parameters were evaluated for neat (PPC0) and reinforced PP (PPC2) to establish the influence of reinforcement on the creep variables like creep rate and creep activation energy. The coefficient parameter A estimated within the stress level range 13.08MPa-22.88MPa has the range 0.0165-0.0651 while the exponent parameter n has 0.299-0.370. The creep stress coefficient K and exponent m has the respective values 161.495 and 0.3288 for PPC0 and 1881.4965 and 0.5448 for PPC2. The value of the parameter p similar to Larson-Miller has the value 4014.1871. Two creep function models used found that PPC0 has higher activation energy with value 9.3642E-20 J/mol for the stress 13.08MPa and PPC2 has values for the stresses 13.08MPa, 19.61MPa and 22.88MPa as 5.55998E- 20J/mol,5.4573E-20J/mol and 4.845E-20J/mol respectively. Of the two master curves produced, that following Larson-Miller parameter is recommended as the relationship between lnσ and parameter f(σ) is relatively linear and will give better results than the curve assumed to follow Sherby-Dorn that will give average result.