This study aimed at improving the tribological and thermal properties of Al alloy using CNTs and Nb nanopowder as reinforcements and spark plasma sintering(SPS)as the fabrication method.The SPS was conducted at 630℃,...This study aimed at improving the tribological and thermal properties of Al alloy using CNTs and Nb nanopowder as reinforcements and spark plasma sintering(SPS)as the fabrication method.The SPS was conducted at 630℃,30 MPa,10 min,and 200℃/min.The tribology test was run with ball-on-disc tribometer using steel ball as the counter body.And the thermal test was processed with thermogravimetric analyzer(TGA)and laser flash apparatus(LFA).Results showed that the addition of 8 wt.%CNTs and 8 wt.%Nb reinforcements respectively decreased the coefficient of friction(COF)of the composite by 79%.The wear volume of the composite was decreased by 23%,and so was the wear rate.However,the thermal conductivity of the composite was equally improved by 44%.The tribology improvement was stimulated by a C film generated by CNTs and a protective Nb2O5 formed by Nb nanopowder.The thermal conductivity was improved by the grain refining property of Nb and the high thermal conductivity of CNTs.Therefore,these results indicated that Al-CNTs-Nb composite is a robust material for high transmission conductor capable of reducing sag and ensuring the durability of the composite.展开更多
Advancements in computational technologies for residential energy management have become widespread due to increased energy usage and peak demand in households.Controlled switching of appliances during peak periods fo...Advancements in computational technologies for residential energy management have become widespread due to increased energy usage and peak demand in households.Controlled switching of appliances during peak periods for energy reduction is one of such solutions.However,this technique may constrict the consumer’s flexibility to utilize desired appliances to fulfil their needs.This study proposes a peak load control technique based on an end-use appliance prioritization and event detection algorithm.A noteworthy feature of the technique is the users’preferred appliance(UPA),which provides the occupants with the flexibility to use any electric load to fulfill their needs at any time whether peak demand control has been initiated or not.Furthermore,to address the challenging issue around the uncertain and varying nature of the users’energy usage pattern,an empirical bottom-up approach is adopted to characterize the consumers’diverse end-use behavior.The results obtained show good performance in terms of peak demand and energy consumption reduction,with 3%to 20%and at least 14.05%in demand reduction for time of use(ToU)periods and energy savings,respectively.These offer a further perspective on demand side management,affording load users a new cost-saving energy usage pattern.展开更多
基金Centre for Energy and Electric Power (CEEP), Tshwane University of Technology, Pretoria, NRF and DHET for providing financial aid to this project
文摘This study aimed at improving the tribological and thermal properties of Al alloy using CNTs and Nb nanopowder as reinforcements and spark plasma sintering(SPS)as the fabrication method.The SPS was conducted at 630℃,30 MPa,10 min,and 200℃/min.The tribology test was run with ball-on-disc tribometer using steel ball as the counter body.And the thermal test was processed with thermogravimetric analyzer(TGA)and laser flash apparatus(LFA).Results showed that the addition of 8 wt.%CNTs and 8 wt.%Nb reinforcements respectively decreased the coefficient of friction(COF)of the composite by 79%.The wear volume of the composite was decreased by 23%,and so was the wear rate.However,the thermal conductivity of the composite was equally improved by 44%.The tribology improvement was stimulated by a C film generated by CNTs and a protective Nb2O5 formed by Nb nanopowder.The thermal conductivity was improved by the grain refining property of Nb and the high thermal conductivity of CNTs.Therefore,these results indicated that Al-CNTs-Nb composite is a robust material for high transmission conductor capable of reducing sag and ensuring the durability of the composite.
基金This work has based on the research supported in part by“the National Research Foundation”of South Africa for the grant,Unique Grant No,107541,Department of Higher Education and Training Research Department Grant(DHET-RDG)and Centre for Energy and Electric Power,Tshwane University of Technology(TUT),South Africa.
文摘Advancements in computational technologies for residential energy management have become widespread due to increased energy usage and peak demand in households.Controlled switching of appliances during peak periods for energy reduction is one of such solutions.However,this technique may constrict the consumer’s flexibility to utilize desired appliances to fulfil their needs.This study proposes a peak load control technique based on an end-use appliance prioritization and event detection algorithm.A noteworthy feature of the technique is the users’preferred appliance(UPA),which provides the occupants with the flexibility to use any electric load to fulfill their needs at any time whether peak demand control has been initiated or not.Furthermore,to address the challenging issue around the uncertain and varying nature of the users’energy usage pattern,an empirical bottom-up approach is adopted to characterize the consumers’diverse end-use behavior.The results obtained show good performance in terms of peak demand and energy consumption reduction,with 3%to 20%and at least 14.05%in demand reduction for time of use(ToU)periods and energy savings,respectively.These offer a further perspective on demand side management,affording load users a new cost-saving energy usage pattern.
