A solid-state storage system is the most practical option for hydrogen because it is more convenient and safer.Metal hydrides,especially MgH_(2),are the most promising materials that offer high gravimetric capacity an...A solid-state storage system is the most practical option for hydrogen because it is more convenient and safer.Metal hydrides,especially MgH_(2),are the most promising materials that offer high gravimetric capacity and good reversibility.However,the practical application of MgH_(2) is restricted by slow sorption kinetics and high stability of thermodynamic properties.Hydrogen storage performance of MgH_(2) was enhanced by introducing the Mg–Na–Al system that destabilises MgH_(2) with NaAlH_(4).The Mg–Na–Al system has superior performance compared to that of unary MgH_(2) and NaAlH_(4).To boost the performance of the Mg–Na–Al system,the ball milling method and the addition of a catalyst were introduced.The Mg–Na–Al system resulted in a low onset decomposition temperature,superior cyclability and enhanced kinetics performances.The Al_(12)Mg_(17) and NaMgH_(3) that formed in situ during the dehydrogenation process modify the reaction pathway of the Mg–Na–Al system and alter the thermodynamic properties.In this paper,the overview of the recent progress in hydrogen storage of the Mg–Na–Al system is detailed.The remaining challenges and future development of Mg–Na–Al system are also discussed.This paper is the first review report on hydrogen storage properties of the Mg–Na–Al system.展开更多
The catalytic effect of K2SiF6 on MgH2 was first timely studied.The MgH2+5 wt.%K2SiF6 was prepared via the ball milling technique.The catalyst had lessened the initial decomposition temperature by 134℃ and 48℃ as co...The catalytic effect of K2SiF6 on MgH2 was first timely studied.The MgH2+5 wt.%K2SiF6 was prepared via the ball milling technique.The catalyst had lessened the initial decomposition temperature by 134℃ and 48℃ as compared to both pristine and milled MgH2 samples,respectively.In 2 minutes,4.5 wt.%of hydrogen was absorbed(250℃)by the doped composite,which was 0.8 wt.%higher than the milled MgH2.Meanwhile,for the desorption kinetics(320℃,1 atm),the amount of desorbed hydrogen was increased by 2.4 wt.%and 2.3 wt.%for the first 10 and 20 minutes.Besides,contracting volume and Johnson-Mehl-Avrami models were used to analyse the kinetics sorptions.The decomposition activation energy calculated based on Kissinger equation was 114 kJ/mol.As for the active species,Mg2Si,MgF2 and KH were formed during the heating process.These active species are speculated to be responsible for the improvement of the hydrogenation properties of the composite.展开更多
Magnesium hydride(MgH_(2))is the most feasible and effective solid-state hydrogen storage material,which has excellent reversibility but initiates decomposing at high temperatures and has slow kinetics performance.Her...Magnesium hydride(MgH_(2))is the most feasible and effective solid-state hydrogen storage material,which has excellent reversibility but initiates decomposing at high temperatures and has slow kinetics performance.Here,zinc titanate(Zn_(2)TiO_(4))synthesised by the solid-state method was used as an additive to lower the initial temperature for dehydrogenation and enhance the re/dehydrogenation behaviour of MgH_(2).With the presence of Zn_(2)TiO_(4),the starting temperature for the dehydrogenation of MgH_(2)was remarkably lowered to around 290℃–305℃.In addition,within 300 s,the MgH_(2)–Zn_(2)TiO_(4)sample absorbed 5.0 wt.%of H_(2)and 2.2–3.6 wt.%H_(2)was liberated from the composite sample in 30 min,which is faster by 22–36 times than as-milled MgH_(2).The activation energy of the MgH_(2)for the dehydrogenation process was also downshifted to 105.5 k J/mol with the addition of Zn_(2)TiO_(4)indicating a decrease of 22%than as-milled MgH_(2).The superior behaviour of MgH_(2)was due to the formation of Mg Zn_(2),MgO and MgTiO_(3),which are responsible for ameliorating the re/dehydrogenation behaviour of MgH_(2).These findings provide a new understanding of the hydrogen storage behaviour of the catalysed-MgH_(2)system.展开更多
Spam has turned into a big predicament these days,due to the increase in the number of spam emails,as the recipient regularly receives piles of emails.Not only is spam wasting users’time and bandwidth.In addition,it ...Spam has turned into a big predicament these days,due to the increase in the number of spam emails,as the recipient regularly receives piles of emails.Not only is spam wasting users’time and bandwidth.In addition,it limits the storage space of the email box as well as the disk space.Thus,spam detection is a challenge for individuals and organizations alike.To advance spam email detection,this work proposes a new spam detection approach,using the grasshopper optimization algorithm(GOA)in training a multilayer perceptron(MLP)classifier for categorizing emails as ham and spam.Hence,MLP and GOA produce an artificial neural network(ANN)model,referred to(GOAMLP).Two corpora are applied Spam Base and UK-2011Web spam for this approach.Finally,the finding represents evidence that the proposed spam detection approach has achieved a better level in spam detection than the status of the art.展开更多
Implementation of biofloc technology(BFT)system in aquaculture industry shows high productivity,low feed conversion ratio,and an optimum culture environment.This study was divided into two phases.The first phase invol...Implementation of biofloc technology(BFT)system in aquaculture industry shows high productivity,low feed conversion ratio,and an optimum culture environment.This study was divided into two phases.The first phase involved maintaining the water quality using the optimum carbon-to-nitrogen ratio by manipulating pH in culture water.The second phase examined the performance of harvesting biofloc(remaining phytoplankton and suspended solids in the system)using chicken eggshell powder(CESP).This study showed that pH 7 to 8 were the best biofloc performance with high removal percentage of ammonia(>99%)with a remaining ammonia concentration of 0.016 mg L^(−1)and 0.018 mg L^(−1),respectively.The second phase of this study was performed to determine the optimal formulation and conditions of using CESP as a bio-flocculant in harvesting excess biofloc.The use of eggshell showed a higher harvesting efficiency of more than 80%under the following treatment conditions:0.25 g L^(−1)of eggshell dosage;with rapid and slow mixing rates of 150 and 30 rpm,respectively;30 min of settling time;settling velocity of 0.39 mm s^(−1)and pH of 6 to 7.Therefore,the results indicated that biofloc would be the best green technology approach for sustainable aquaculture wastewater and the CESP is an organic matrix that environmental-friendly bio-coagulant for biofloc harvesting.展开更多
Properly created and securely communicated,non-disclosure agreement(NDA)can resolve most of the common disputes related to outsourcing of offshore software maintenance(OSMO).Occasionally,these NDAs are in the form of ...Properly created and securely communicated,non-disclosure agreement(NDA)can resolve most of the common disputes related to outsourcing of offshore software maintenance(OSMO).Occasionally,these NDAs are in the form of images.Since the work is done offshore,these agreements or images must be shared through the Internet or stored over the cloud.The breach of privacy,on the other hand,is a potential threat for the image owners as both the Internet and cloud servers are not void of danger.This article proposes a novel algorithm for securing the NDAs in the form of images.As an agreement is signed between the two parties,it will be encrypted before sending to the cloud server or travelling through the public network,the Internet.As the image is input to the algorithm,its pixels would be scrambled through the set of randomly generated rectangles for an arbitrary amount of time.The confusion effects have been realized through an XOR operation between the confused image,and chaotic data.Besides,5D multi-wing hyperchaotic system has been employed to spawn the chaotic vectors due to good properties of chaoticity it has.The machine experimentation and the security analysis through a comprehensive set of validation metric vividly demonstrate the robustness,defiance to the multifarious threats and the prospects for some real-world application of the proposed encryption algorithm for the NDA images.展开更多
Chemical compounds are modeled as graphs.The atoms of molecules represent the graph vertices while chemical bonds between the atoms express the edges.The topological indices representing the molecular graph correspond...Chemical compounds are modeled as graphs.The atoms of molecules represent the graph vertices while chemical bonds between the atoms express the edges.The topological indices representing the molecular graph corresponds to the different chemical properties of compounds.Let a,b be are two positive integers,andΓ(Z_(a)×Z_(b))be the zero-divisor graph of the commutative ring Z_(a)×Z_(b).In this article some direct questions have been answered that can be utilized latterly in different applications.This study starts with simple computations,leading to a quite complex ring theoretic problems to prove certain properties.The theory of finite commutative rings is useful due to its different applications in the fields of advanced mechanics,communication theory,cryptography,combinatorics,algorithms analysis,and engineering.In this paper we determine the distance-based topological polynomials and indices of the zero-divisor graph of the commutative ring Z_(p^(2))×Z_(q)(for p,q as prime numbers)with the help of graphical structure analysis.The study outcomes help in understanding the fundamental relation between ring-theoretic and graph-theoretic properties of a zero-divisor graphΓ(G).展开更多
The successful execution and management of Offshore Software Maintenance Outsourcing(OSMO)can be very beneficial for OSMO vendors and the OSMO client.Although a lot of research on software outsourcing is going on,most...The successful execution and management of Offshore Software Maintenance Outsourcing(OSMO)can be very beneficial for OSMO vendors and the OSMO client.Although a lot of research on software outsourcing is going on,most of the existing literature on offshore outsourcing deals with the outsourcing of software development only.Several frameworks have been developed focusing on guiding software systemmanagers concerning offshore software outsourcing.However,none of these studies delivered comprehensive guidelines for managing the whole process of OSMO.There is a considerable lack of research working on managing OSMO from a vendor’s perspective.Therefore,to find the best practices for managing an OSMO process,it is necessary to further investigate such complex and multifaceted phenomena from the vendor’s perspective.This study validated the preliminary OSMO process model via a case study research approach.The results showed that the OSMO process model is applicable in an industrial setting with few changes.The industrial data collected during the case study enabled this paper to extend the preliminary OSMO process model.The refined version of the OSMO processmodel has four major phases including(i)Project Assessment,(ii)SLA(iii)Execution,and(iv)Risk.展开更多
Software maintenance is the process of fixing,modifying,and improving software deliverables after they are delivered to the client.Clients can benefit from offshore software maintenance outsourcing(OSMO)in different w...Software maintenance is the process of fixing,modifying,and improving software deliverables after they are delivered to the client.Clients can benefit from offshore software maintenance outsourcing(OSMO)in different ways,including time savings,cost savings,and improving the software quality and value.One of the hardest challenges for the OSMO vendor is to choose a suitable project among several clients’projects.The goal of the current study is to recommend a machine learning-based decision support system that OSMO vendors can utilize to forecast or assess the project of OSMO clients.The projects belong to OSMO vendors,having offices in developing countries while providing services to developed countries.In the current study,Extreme Learning Machine’s(ELM’s)variant called Deep Extreme Learning Machines(DELMs)is used.A novel dataset consisting of 195 projects data is proposed to train the model and to evaluate the overall efficiency of the proposed model.The proposed DELM’s based model evaluations achieved 90.017%training accuracy having a value with 1.412×10^(-3) Root Mean Square Error(RMSE)and 85.772%testing accuracy with 1.569×10^(-3) RMSE with five DELMs hidden layers.The results express that the suggested model has gained a notable recognition rate in comparison to any previous studies.The current study also concludes DELMs as the most applicable and useful technique for OSMO client’s project assessment.展开更多
The recent boom of economic activities has escalated the demand for oil that eventually will affect its prices.However,oil prices are difficult to predict because most of the factors affecting oil prices are vague and...The recent boom of economic activities has escalated the demand for oil that eventually will affect its prices.However,oil prices are difficult to predict because most of the factors affecting oil prices are vague and intangible.The challenges in predicting oil prices urgently require a novel approach where issues related to multiple-factors,uncertainty,and periodicity can be addressed.The authors propose the single-valued neutrosophic relations based decision-making method inspired by the three memberships of neutrosophic sets,and amplitude and periodicity of complex numbers.The proposed method is applied to the case of oil prices where six factors affecting oil prices and six benchmarks measuring oil prices are employed.This new method combines with complex neutrosophic numbers and algebraic relations,and can suggest the most influential factor that affects oil prices.Considering the periodicity of 24 months,computation results verify the‘global economic rate’as the most influential factor that affects the prices of oil.The main contribution of this study is the development of a neutrosophic relations-based decision-making method to suggest the most influential factor that affects oil prices.The result provides evidence on the feasibility of the proposed method in suggesting the influential factors that affect oil prices.展开更多
In this work, we consider the second order nonlinear integro-differential Equation (IDEs) of the Volterra-Fredholm type. One of the popular methods for solving Volterra or Fredholm type IDEs is the method of quadratur...In this work, we consider the second order nonlinear integro-differential Equation (IDEs) of the Volterra-Fredholm type. One of the popular methods for solving Volterra or Fredholm type IDEs is the method of quadrature while the problem of consideration is a linear problem. If IDEs are nonlinear or integral kernel is complicated, then quadrature rule is not most suitable;therefore, other types of methods are needed to develop. One of the suitable and effective method is homotopy analysis method (HAM) developed by Liao in 1992. To apply HAM, we firstly reduced the IDEs into nonlinear integral Equation (IEs) of Volterra-Fredholm type;then the standard HAM was applied. Gauss-Legendre quadrature formula was used for kernel integrations. Obtained system of algebraic equations was solved numerically. Moreover, numerical examples demonstrate the high accuracy of the proposed method. Comparisons with other methods are also provided. The results show that the proposed method is simple, effective and dominated other methods.展开更多
The Li-Mg-B-H composite(2LiBH_(4)+MgH_(2))has a high capacity of 11.4 wt%as a hydrogen storage material.However,the slow kinetics and poor cycling stability severely restrict its practical applications.In this work,a ...The Li-Mg-B-H composite(2LiBH_(4)+MgH_(2))has a high capacity of 11.4 wt%as a hydrogen storage material.However,the slow kinetics and poor cycling stability severely restrict its practical applications.In this work,a layered Nb_(2)C MXene was first synthesized and then introduced to tailor the kinetics and cycling stability of the Li-Mg-B-H composite.The milled 2LiH+MgB_(2)composites were initially hydrogenated to obtain the 2LiBH_(4)+MgH_(2)composites.The 2LiBH_(4)+MgH_(2)+5wt%Nb_(2)C can release 9.0 wt%H_(2)in 30 min at 400℃,while it is only 2.7 wt%for the undoped 2LiBH_(4)+MgH_(2).The dehydrogenation activation energies of MgH_(2)and LiBH_(4)are 123 and 154 kJ·mol^(-1)respectively for the 5 wt%Nb_(2)C-doped composite,lower than the undoped composite(164 and 165 kJ·mol^(-1)).The 2LiBH_(4)+MgH_(2)+5 wt%Nb_(2)C possesses excellent cycling stability,with the reversible capacity only slightly reduced from 9.4 wt%for the 1st cycle to 9.3 wt%for the 20th cycle.Nb_(2)C keeps stable in the composite and acts as an efficient catalyst for the Li-Mg-B-H composite.It is believed that both the layered structure and the active Nb element contribu te to the enhanced hydrogen storage performances of the Li-Mg-B-H composite.This work confirms that the Nb_(2)C MXene with layered stru cture has a significant enhancing impact on the Li-Mg-B-H hydrogen storage materials,which is different from the bulk NbC.展开更多
This paper aims to assess the effect of dry band location of contaminated porcelain insulators under various flashover voltages due to humidity.Four locations of dry bands are proposed to be tested under different sev...This paper aims to assess the effect of dry band location of contaminated porcelain insulators under various flashover voltages due to humidity.Four locations of dry bands are proposed to be tested under different severity of contamination artificially produce using salt deposit density(SDD)sprayed on an insulator.Laboratory tests of polluted insulators under proposed scenarios have been conducted.The flashover voltage of clean insulators has been identified as a reference value to analyze the effect of contamination distribution and its severity.The dry band dimension has been taken into consideration in experimental tests.The flashover voltage has been predicted using an artificial neural network(ANN)technique based on the laboratory test data.The ANN approach is constructed with five input data(geometry the insulator and parameters of contamination)and flashover voltage as the output of the model.Results indicated that the pollution distribution based on the proposed scenario has a significant influence on the flashover voltage performances.Validation of the ANN model reveals that the relative error values between the experimental results and the prediction appeared to be within 5%.This indicates the significant efficiency of the ANN technique in predicting the flashover voltage insulator under test.展开更多
Cloud Technology is a new platform that offers on-demand computing Peripheral such as storage,processing power,and other computer system resources.It is also referred to as a system that will let the consumers utilize...Cloud Technology is a new platform that offers on-demand computing Peripheral such as storage,processing power,and other computer system resources.It is also referred to as a system that will let the consumers utilize computational resources like databases,servers,storage,and intelligence over the Internet.In a cloud network,load balancing is the process of dividing network traffic among a cluster of available servers to increase efficiency.It is also known as a server pool or server farm.When a single node is overwhelmed,balancing the workload is needed to manage unpredictable workflows.The load balancer sends the load to another free node in this case.We focus on the Balancing of workflows with the proposed approach,and we present a novel method to balance the load that manages the dynamic scheduling process.One of the preexisting load balancing techniques is considered,however it is somewhat modified to fit the scenario at hand.Depending on the experimentation’s findings,it is concluded that this suggested approach improves load balancing consistency,response time,and throughput by 6%.展开更多
Urban pollution has now become increasingly recognized as an important determinant of air pollution in developed countries. The effect of urban air pollution in developing countries, on the other hand, has not been ad...Urban pollution has now become increasingly recognized as an important determinant of air pollution in developed countries. The effect of urban air pollution in developing countries, on the other hand, has not been adequately addressed in the data Spatio-temporal time series. Thus, this study was intended to characterize the effect of urbanization on air pollution for an urbanized Klang Valley, Malaysia using Spatio-temporal data from 2008 to 2017. The Air Pollution Index (API) data and local pollutant concentration were employed to establish the links between urban air pollution. The analysis will be supported by determining the source of pollutants during the study period using</span></span><span><span><span style="font-family:""> Principal Component Analysis (PCA)</span></span></span><span><span><span style="font-family:"">.</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">The study identified </span></span></span><span><span><span style="font-family:"">that Carbon monoxide (CO), Nitrogen Dioxide (NO<sub>2</sub>), and Ozone (O<sub>3</sub>) are </span></span></span><span><span><span style="font-family:"">the major air pollution that has contributed to degrading air quality in the Klang Valley due to the vehicles, combustion process, and industries.展开更多
Many MXenes are efficient catalysts for MgH_(2)hydrogen storage material.Nevertheless,the synthesis of MXenes should consume a large amount of corrosive HF to etch out the Al layers from the transition metal aluminum ...Many MXenes are efficient catalysts for MgH_(2)hydrogen storage material.Nevertheless,the synthesis of MXenes should consume a large amount of corrosive HF to etch out the Al layers from the transition metal aluminum carbides or nitrides(MAX) phases,which is environmentally unfriendly.In this work,Ti_(3)AlCN MAX without HFetching was employed directly to observably enhance the kinetics and the cycling stability of MgH_(2).With addition of10 wt% Ti_(3)AlCN,the onset dehydrogenation temperature of MgH2 was dropped from 320 to 205℃,and the rehydrogenation of MgH2 under 6 MPa H2 began at as low as50℃.Furthermore,at 300℃,it could provide 6.2 wt% of hydrogen in 10 min.Upon cycling,the composite underwent an activation process during the initial 40 cycles,with the reversible capacity increased from 4.7 wt% to 6.5 wt%.After that,the capacity showed almost no attenuation for up to 100 cycles.The enhancing effect of Ti_(3)AICN on MgH_(2) was comparable to many MXenes.It was demonstrated that Ti_(3)AICN did not destabilize MgH_(2) but acted as an efficient catalyst for MgH_(2).Ti_(3)AICN was observed to be the active sites for the nucleation and growth of MgH_(2)and might also help in dissociation and recombination of hydrogen molecules.Such two factors are believed to contribute to the improvement of MgH_(2).This study not only provides a promising strategy for improving the hydrogen storage performances of MgH_(2) by using noncorrosive MAX materials,but also adds evidence of nucleation and growth of MgH_(2) on a catalyst.展开更多
基金This work was supported by the Ministry of Higher Education Malaysia through the Fundamental Research Grant Scheme(FRGS/1/2019/STG07/UMT/02/5)The authors also thank the Universiti Malaysia Terengganu for providing the facilities to carry out this project.Scheme(FRGS/1/2019/STG07/UMT/02/5)The authors also thank the Universiti Malaysia Terengganu for providing the facilities to carry out this project.
文摘A solid-state storage system is the most practical option for hydrogen because it is more convenient and safer.Metal hydrides,especially MgH_(2),are the most promising materials that offer high gravimetric capacity and good reversibility.However,the practical application of MgH_(2) is restricted by slow sorption kinetics and high stability of thermodynamic properties.Hydrogen storage performance of MgH_(2) was enhanced by introducing the Mg–Na–Al system that destabilises MgH_(2) with NaAlH_(4).The Mg–Na–Al system has superior performance compared to that of unary MgH_(2) and NaAlH_(4).To boost the performance of the Mg–Na–Al system,the ball milling method and the addition of a catalyst were introduced.The Mg–Na–Al system resulted in a low onset decomposition temperature,superior cyclability and enhanced kinetics performances.The Al_(12)Mg_(17) and NaMgH_(3) that formed in situ during the dehydrogenation process modify the reaction pathway of the Mg–Na–Al system and alter the thermodynamic properties.In this paper,the overview of the recent progress in hydrogen storage of the Mg–Na–Al system is detailed.The remaining challenges and future development of Mg–Na–Al system are also discussed.This paper is the first review report on hydrogen storage properties of the Mg–Na–Al system.
基金the Universiti Malaysia Terengganu(UMT)through the Golden Goose Research Grant(GGRG)(VOT 55190).
文摘The catalytic effect of K2SiF6 on MgH2 was first timely studied.The MgH2+5 wt.%K2SiF6 was prepared via the ball milling technique.The catalyst had lessened the initial decomposition temperature by 134℃ and 48℃ as compared to both pristine and milled MgH2 samples,respectively.In 2 minutes,4.5 wt.%of hydrogen was absorbed(250℃)by the doped composite,which was 0.8 wt.%higher than the milled MgH2.Meanwhile,for the desorption kinetics(320℃,1 atm),the amount of desorbed hydrogen was increased by 2.4 wt.%and 2.3 wt.%for the first 10 and 20 minutes.Besides,contracting volume and Johnson-Mehl-Avrami models were used to analyse the kinetics sorptions.The decomposition activation energy calculated based on Kissinger equation was 114 kJ/mol.As for the active species,Mg2Si,MgF2 and KH were formed during the heating process.These active species are speculated to be responsible for the improvement of the hydrogenation properties of the composite.
基金Universiti Malaysia Terengganu(UMT)for the funding provided by Golden Goose Research Grant(GGRG)VOT 55190。
文摘Magnesium hydride(MgH_(2))is the most feasible and effective solid-state hydrogen storage material,which has excellent reversibility but initiates decomposing at high temperatures and has slow kinetics performance.Here,zinc titanate(Zn_(2)TiO_(4))synthesised by the solid-state method was used as an additive to lower the initial temperature for dehydrogenation and enhance the re/dehydrogenation behaviour of MgH_(2).With the presence of Zn_(2)TiO_(4),the starting temperature for the dehydrogenation of MgH_(2)was remarkably lowered to around 290℃–305℃.In addition,within 300 s,the MgH_(2)–Zn_(2)TiO_(4)sample absorbed 5.0 wt.%of H_(2)and 2.2–3.6 wt.%H_(2)was liberated from the composite sample in 30 min,which is faster by 22–36 times than as-milled MgH_(2).The activation energy of the MgH_(2)for the dehydrogenation process was also downshifted to 105.5 k J/mol with the addition of Zn_(2)TiO_(4)indicating a decrease of 22%than as-milled MgH_(2).The superior behaviour of MgH_(2)was due to the formation of Mg Zn_(2),MgO and MgTiO_(3),which are responsible for ameliorating the re/dehydrogenation behaviour of MgH_(2).These findings provide a new understanding of the hydrogen storage behaviour of the catalysed-MgH_(2)system.
文摘Spam has turned into a big predicament these days,due to the increase in the number of spam emails,as the recipient regularly receives piles of emails.Not only is spam wasting users’time and bandwidth.In addition,it limits the storage space of the email box as well as the disk space.Thus,spam detection is a challenge for individuals and organizations alike.To advance spam email detection,this work proposes a new spam detection approach,using the grasshopper optimization algorithm(GOA)in training a multilayer perceptron(MLP)classifier for categorizing emails as ham and spam.Hence,MLP and GOA produce an artificial neural network(ANN)model,referred to(GOAMLP).Two corpora are applied Spam Base and UK-2011Web spam for this approach.Finally,the finding represents evidence that the proposed spam detection approach has achieved a better level in spam detection than the status of the art.
文摘Implementation of biofloc technology(BFT)system in aquaculture industry shows high productivity,low feed conversion ratio,and an optimum culture environment.This study was divided into two phases.The first phase involved maintaining the water quality using the optimum carbon-to-nitrogen ratio by manipulating pH in culture water.The second phase examined the performance of harvesting biofloc(remaining phytoplankton and suspended solids in the system)using chicken eggshell powder(CESP).This study showed that pH 7 to 8 were the best biofloc performance with high removal percentage of ammonia(>99%)with a remaining ammonia concentration of 0.016 mg L^(−1)and 0.018 mg L^(−1),respectively.The second phase of this study was performed to determine the optimal formulation and conditions of using CESP as a bio-flocculant in harvesting excess biofloc.The use of eggshell showed a higher harvesting efficiency of more than 80%under the following treatment conditions:0.25 g L^(−1)of eggshell dosage;with rapid and slow mixing rates of 150 and 30 rpm,respectively;30 min of settling time;settling velocity of 0.39 mm s^(−1)and pH of 6 to 7.Therefore,the results indicated that biofloc would be the best green technology approach for sustainable aquaculture wastewater and the CESP is an organic matrix that environmental-friendly bio-coagulant for biofloc harvesting.
基金This research is fully funded by Universiti Teknologi Malaysia under the UTM Fundamental Research Grant(UTMFR)with Cost Center No Q.K130000.2556.21H14.
文摘Properly created and securely communicated,non-disclosure agreement(NDA)can resolve most of the common disputes related to outsourcing of offshore software maintenance(OSMO).Occasionally,these NDAs are in the form of images.Since the work is done offshore,these agreements or images must be shared through the Internet or stored over the cloud.The breach of privacy,on the other hand,is a potential threat for the image owners as both the Internet and cloud servers are not void of danger.This article proposes a novel algorithm for securing the NDAs in the form of images.As an agreement is signed between the two parties,it will be encrypted before sending to the cloud server or travelling through the public network,the Internet.As the image is input to the algorithm,its pixels would be scrambled through the set of randomly generated rectangles for an arbitrary amount of time.The confusion effects have been realized through an XOR operation between the confused image,and chaotic data.Besides,5D multi-wing hyperchaotic system has been employed to spawn the chaotic vectors due to good properties of chaoticity it has.The machine experimentation and the security analysis through a comprehensive set of validation metric vividly demonstrate the robustness,defiance to the multifarious threats and the prospects for some real-world application of the proposed encryption algorithm for the NDA images.
文摘Chemical compounds are modeled as graphs.The atoms of molecules represent the graph vertices while chemical bonds between the atoms express the edges.The topological indices representing the molecular graph corresponds to the different chemical properties of compounds.Let a,b be are two positive integers,andΓ(Z_(a)×Z_(b))be the zero-divisor graph of the commutative ring Z_(a)×Z_(b).In this article some direct questions have been answered that can be utilized latterly in different applications.This study starts with simple computations,leading to a quite complex ring theoretic problems to prove certain properties.The theory of finite commutative rings is useful due to its different applications in the fields of advanced mechanics,communication theory,cryptography,combinatorics,algorithms analysis,and engineering.In this paper we determine the distance-based topological polynomials and indices of the zero-divisor graph of the commutative ring Z_(p^(2))×Z_(q)(for p,q as prime numbers)with the help of graphical structure analysis.The study outcomes help in understanding the fundamental relation between ring-theoretic and graph-theoretic properties of a zero-divisor graphΓ(G).
基金This research is fully funded byUniversiti Malaysia Terengganu under the research Grant(PGRG).
文摘The successful execution and management of Offshore Software Maintenance Outsourcing(OSMO)can be very beneficial for OSMO vendors and the OSMO client.Although a lot of research on software outsourcing is going on,most of the existing literature on offshore outsourcing deals with the outsourcing of software development only.Several frameworks have been developed focusing on guiding software systemmanagers concerning offshore software outsourcing.However,none of these studies delivered comprehensive guidelines for managing the whole process of OSMO.There is a considerable lack of research working on managing OSMO from a vendor’s perspective.Therefore,to find the best practices for managing an OSMO process,it is necessary to further investigate such complex and multifaceted phenomena from the vendor’s perspective.This study validated the preliminary OSMO process model via a case study research approach.The results showed that the OSMO process model is applicable in an industrial setting with few changes.The industrial data collected during the case study enabled this paper to extend the preliminary OSMO process model.The refined version of the OSMO processmodel has four major phases including(i)Project Assessment,(ii)SLA(iii)Execution,and(iv)Risk.
基金fully funded by Universiti Teknologi Malaysia under the UTM Fundamental Research Grant(UTMFR)with Cost Center No Q.K130000.2556.21H14.
文摘Software maintenance is the process of fixing,modifying,and improving software deliverables after they are delivered to the client.Clients can benefit from offshore software maintenance outsourcing(OSMO)in different ways,including time savings,cost savings,and improving the software quality and value.One of the hardest challenges for the OSMO vendor is to choose a suitable project among several clients’projects.The goal of the current study is to recommend a machine learning-based decision support system that OSMO vendors can utilize to forecast or assess the project of OSMO clients.The projects belong to OSMO vendors,having offices in developing countries while providing services to developed countries.In the current study,Extreme Learning Machine’s(ELM’s)variant called Deep Extreme Learning Machines(DELMs)is used.A novel dataset consisting of 195 projects data is proposed to train the model and to evaluate the overall efficiency of the proposed model.The proposed DELM’s based model evaluations achieved 90.017%training accuracy having a value with 1.412×10^(-3) Root Mean Square Error(RMSE)and 85.772%testing accuracy with 1.569×10^(-3) RMSE with five DELMs hidden layers.The results express that the suggested model has gained a notable recognition rate in comparison to any previous studies.The current study also concludes DELMs as the most applicable and useful technique for OSMO client’s project assessment.
文摘The recent boom of economic activities has escalated the demand for oil that eventually will affect its prices.However,oil prices are difficult to predict because most of the factors affecting oil prices are vague and intangible.The challenges in predicting oil prices urgently require a novel approach where issues related to multiple-factors,uncertainty,and periodicity can be addressed.The authors propose the single-valued neutrosophic relations based decision-making method inspired by the three memberships of neutrosophic sets,and amplitude and periodicity of complex numbers.The proposed method is applied to the case of oil prices where six factors affecting oil prices and six benchmarks measuring oil prices are employed.This new method combines with complex neutrosophic numbers and algebraic relations,and can suggest the most influential factor that affects oil prices.Considering the periodicity of 24 months,computation results verify the‘global economic rate’as the most influential factor that affects the prices of oil.The main contribution of this study is the development of a neutrosophic relations-based decision-making method to suggest the most influential factor that affects oil prices.The result provides evidence on the feasibility of the proposed method in suggesting the influential factors that affect oil prices.
文摘In this work, we consider the second order nonlinear integro-differential Equation (IDEs) of the Volterra-Fredholm type. One of the popular methods for solving Volterra or Fredholm type IDEs is the method of quadrature while the problem of consideration is a linear problem. If IDEs are nonlinear or integral kernel is complicated, then quadrature rule is not most suitable;therefore, other types of methods are needed to develop. One of the suitable and effective method is homotopy analysis method (HAM) developed by Liao in 1992. To apply HAM, we firstly reduced the IDEs into nonlinear integral Equation (IEs) of Volterra-Fredholm type;then the standard HAM was applied. Gauss-Legendre quadrature formula was used for kernel integrations. Obtained system of algebraic equations was solved numerically. Moreover, numerical examples demonstrate the high accuracy of the proposed method. Comparisons with other methods are also provided. The results show that the proposed method is simple, effective and dominated other methods.
基金financially supported by the Science and Technology Department of Guangxi Zhuang Autonomous(No.GuiKeAD21238022)the National Natural Science Foundation of China(Nos.52001079,22379030 and 52261038)Quzhou Science and Technology Project(No.2022K103)。
文摘The Li-Mg-B-H composite(2LiBH_(4)+MgH_(2))has a high capacity of 11.4 wt%as a hydrogen storage material.However,the slow kinetics and poor cycling stability severely restrict its practical applications.In this work,a layered Nb_(2)C MXene was first synthesized and then introduced to tailor the kinetics and cycling stability of the Li-Mg-B-H composite.The milled 2LiH+MgB_(2)composites were initially hydrogenated to obtain the 2LiBH_(4)+MgH_(2)composites.The 2LiBH_(4)+MgH_(2)+5wt%Nb_(2)C can release 9.0 wt%H_(2)in 30 min at 400℃,while it is only 2.7 wt%for the undoped 2LiBH_(4)+MgH_(2).The dehydrogenation activation energies of MgH_(2)and LiBH_(4)are 123 and 154 kJ·mol^(-1)respectively for the 5 wt%Nb_(2)C-doped composite,lower than the undoped composite(164 and 165 kJ·mol^(-1)).The 2LiBH_(4)+MgH_(2)+5 wt%Nb_(2)C possesses excellent cycling stability,with the reversible capacity only slightly reduced from 9.4 wt%for the 1st cycle to 9.3 wt%for the 20th cycle.Nb_(2)C keeps stable in the composite and acts as an efficient catalyst for the Li-Mg-B-H composite.It is believed that both the layered structure and the active Nb element contribu te to the enhanced hydrogen storage performances of the Li-Mg-B-H composite.This work confirms that the Nb_(2)C MXene with layered stru cture has a significant enhancing impact on the Li-Mg-B-H hydrogen storage materials,which is different from the bulk NbC.
文摘This paper aims to assess the effect of dry band location of contaminated porcelain insulators under various flashover voltages due to humidity.Four locations of dry bands are proposed to be tested under different severity of contamination artificially produce using salt deposit density(SDD)sprayed on an insulator.Laboratory tests of polluted insulators under proposed scenarios have been conducted.The flashover voltage of clean insulators has been identified as a reference value to analyze the effect of contamination distribution and its severity.The dry band dimension has been taken into consideration in experimental tests.The flashover voltage has been predicted using an artificial neural network(ANN)technique based on the laboratory test data.The ANN approach is constructed with five input data(geometry the insulator and parameters of contamination)and flashover voltage as the output of the model.Results indicated that the pollution distribution based on the proposed scenario has a significant influence on the flashover voltage performances.Validation of the ANN model reveals that the relative error values between the experimental results and the prediction appeared to be within 5%.This indicates the significant efficiency of the ANN technique in predicting the flashover voltage insulator under test.
基金supported by the project:“Research and Implementation of Innovative Solutions for Monitoring Consumption in Technical Installations Using Artificial Intelligence”,beneficiary S.C.REMONI TECHNOLOGIES RO S.R.L in partnership with“Gheorghe Asachi”Technical University of Iasi,Financing Contract No.400/390076/26.11.2021,SMIS Code 121866,financed by POC/163/1/3.
文摘Cloud Technology is a new platform that offers on-demand computing Peripheral such as storage,processing power,and other computer system resources.It is also referred to as a system that will let the consumers utilize computational resources like databases,servers,storage,and intelligence over the Internet.In a cloud network,load balancing is the process of dividing network traffic among a cluster of available servers to increase efficiency.It is also known as a server pool or server farm.When a single node is overwhelmed,balancing the workload is needed to manage unpredictable workflows.The load balancer sends the load to another free node in this case.We focus on the Balancing of workflows with the proposed approach,and we present a novel method to balance the load that manages the dynamic scheduling process.One of the preexisting load balancing techniques is considered,however it is somewhat modified to fit the scenario at hand.Depending on the experimentation’s findings,it is concluded that this suggested approach improves load balancing consistency,response time,and throughput by 6%.
文摘Urban pollution has now become increasingly recognized as an important determinant of air pollution in developed countries. The effect of urban air pollution in developing countries, on the other hand, has not been adequately addressed in the data Spatio-temporal time series. Thus, this study was intended to characterize the effect of urbanization on air pollution for an urbanized Klang Valley, Malaysia using Spatio-temporal data from 2008 to 2017. The Air Pollution Index (API) data and local pollutant concentration were employed to establish the links between urban air pollution. The analysis will be supported by determining the source of pollutants during the study period using</span></span><span><span><span style="font-family:""> Principal Component Analysis (PCA)</span></span></span><span><span><span style="font-family:"">.</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">The study identified </span></span></span><span><span><span style="font-family:"">that Carbon monoxide (CO), Nitrogen Dioxide (NO<sub>2</sub>), and Ozone (O<sub>3</sub>) are </span></span></span><span><span><span style="font-family:"">the major air pollution that has contributed to degrading air quality in the Klang Valley due to the vehicles, combustion process, and industries.
基金financially supported by the Science and Technology Department of Guangxi Zhuang Autonomous (No.GuiKeAD21238022)the Natural Science Foundation of Guangxi Province (No.2019GXNSFBA185004)National Natural Science Foundation of China (Nos.52001079,51961005 and 52261038)。
文摘Many MXenes are efficient catalysts for MgH_(2)hydrogen storage material.Nevertheless,the synthesis of MXenes should consume a large amount of corrosive HF to etch out the Al layers from the transition metal aluminum carbides or nitrides(MAX) phases,which is environmentally unfriendly.In this work,Ti_(3)AlCN MAX without HFetching was employed directly to observably enhance the kinetics and the cycling stability of MgH_(2).With addition of10 wt% Ti_(3)AlCN,the onset dehydrogenation temperature of MgH2 was dropped from 320 to 205℃,and the rehydrogenation of MgH2 under 6 MPa H2 began at as low as50℃.Furthermore,at 300℃,it could provide 6.2 wt% of hydrogen in 10 min.Upon cycling,the composite underwent an activation process during the initial 40 cycles,with the reversible capacity increased from 4.7 wt% to 6.5 wt%.After that,the capacity showed almost no attenuation for up to 100 cycles.The enhancing effect of Ti_(3)AICN on MgH_(2) was comparable to many MXenes.It was demonstrated that Ti_(3)AICN did not destabilize MgH_(2) but acted as an efficient catalyst for MgH_(2).Ti_(3)AICN was observed to be the active sites for the nucleation and growth of MgH_(2)and might also help in dissociation and recombination of hydrogen molecules.Such two factors are believed to contribute to the improvement of MgH_(2).This study not only provides a promising strategy for improving the hydrogen storage performances of MgH_(2) by using noncorrosive MAX materials,but also adds evidence of nucleation and growth of MgH_(2) on a catalyst.
