AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir...AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir welding （FSW） tools and FSW welders. These models may be further helpful for making process parameter choice for this sort of alloy, defining welding program and control of process parameters by using computer numerical control friction stir welding welders. The results show that tool rotational speed, welding speed and tool shoulder diameter are most significant parameters affecting axial force and heat input, while longitudinal force is significantly affected by welding speed and probe diameter.展开更多
The heat treatable aluminum-copper alloy AA2014 finds wide application in the aerospace and defence industry due to its high strength-toweight ratio and good ductility. Friction stir welding(FSW) process, an emerging ...The heat treatable aluminum-copper alloy AA2014 finds wide application in the aerospace and defence industry due to its high strength-toweight ratio and good ductility. Friction stir welding(FSW) process, an emerging solid state joining process, is suitable for joining this alloy compared to fusion welding processes. This work presents the formulation of a mathematical model with process parameters and tool geometry to predict the responses of friction stir welds of AA 2014-T6 aluminum alloy, viz yield strength, tensile strength and ductility. The most influential process parameters considered are spindle speed, welding speed, tilt angle and tool pin profile. A four-factor, five-level central composite design was used and a response surface methodology(RSM) was employed to develop the regression models to predict the responses.The mechanical properties, such as yield strength(YS), ultimate tensile strength(UTS) and percentage elongation(%El), are considered as responses. Method of analysis of variance was used to determine the important process parameters that affect the responses. Validation trials were carried out to validate these results. These results indicate that the friction stir welds of AA 2014-T6 aluminum alloy welded with hexagonal tool pin profile have the highest tensile strength and elongation, whereas the joints fabricated with conical tool pin profile have the lowest tensile strength and elongation.展开更多
The full-scale application of Tx-1, a multifunctional microbial agent, was carried out for 8 months in an anoxic/oxic（A/O） municipal wastewater treatment process. The results show that the Tx-1 dosed system can obta...The full-scale application of Tx-1, a multifunctional microbial agent, was carried out for 8 months in an anoxic/oxic（A/O） municipal wastewater treatment process. The results show that the Tx-1 dosed system can obtain good effluent characteristics while minimizing sludge production and energy consumption. The total phosphorus（TP） is lower than0. 5 mg/L in effluent without any chemical regent added. The discharged dry sludge per 10 000 m^3 wastewater Dwat decreases from 1. 4 to 0. 5 t. For per cubic meter wastewater, the air supply decreases from 6. 0 to 5. 1 m^3 and the electricity consumption decreases from 0. 412- 0. 425 kW·h to 0. 331 kW·h. The addition of Tx-1 can improve the substrate removal constant and decrease the microorganism growth yield coefficient of activated sludge. At the same time,the structure of the microbial community changes and the biodiversity increases by adding Tx-1. The abundance of polyphosphate accumulating organisms（PAO）, Comamonadaceae and Tetrasphaera, increased. Effective microbial agent is a potential way to combine in-situ sludge minimization with contaminants removal.展开更多
This paper reports a novel micro-blast driven manufacturing process for micro-forming of Aluminum foils. The micro-blast is realized by using a nanoenergetic material system comprising of Bi_2O_3 microrods and aluminu...This paper reports a novel micro-blast driven manufacturing process for micro-forming of Aluminum foils. The micro-blast is realized by using a nanoenergetic material system comprising of Bi_2O_3 microrods and aluminum particles. There is an enhanced need of forming of thin aluminum foil structures in small regions from point of view of drug packaging etc. The process developed caters to this need by using a single shot forming process using a micro-blast source. The micro-blast that is generated from an energetic composite system is made highly tunable by modulating the peak pressure generated through the blasting process and their impact in micro-forming of thin aluminum foils is observed through parametric studies. The engineering challenge involved in these experiments is to tune the blast pressure properties in order to address the forming of thin metal sheets with limiting boundary values as defined by the failure criteria. A variety of characterization techniques related to a thorough analysis of the synthesized material viz. X-ray diffraction(XRD), Scanning Electron Microscopy(SEM) etc, are used to tune the functional properties like gauge blast pressure etc, of material system. We have found a material system that can generate a maximum peak pressure of 73.8 MPa with pressurization rate of 2460 GPas^(-1) and that is able to accomplish micro-forming on thin metal foils(around 0.3 mm thickness). Experimental investigations demonstrate that tunabilty aspect of the energetic composites when exercised can enable variant processes such as embossing, coining, drilling etc. which may be of significant utility to drug packaging industries. A proper mathematical modeling of the forming process and critical process parameters therein have also been detailed.展开更多
In present study, BP neural network model was proposed for the prediction of ultimate compressive strength of Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting. The inputs of the BP neural network mo...In present study, BP neural network model was proposed for the prediction of ultimate compressive strength of Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting. The inputs of the BP neural network model were the applied load on the epispastic polystyrene template （F）, centrifugal acceleration （v） and sintering temperature （T）, while the only output was the ultimate compressive strength （（7）. According to the registered BP model, the effects of F, v, T on 0 were analyzed. The predicted results agree with the actual data within reasonable experimental error, indicating that the BP model is practically a very useful tool in property prediction and process parameter design of the Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting.展开更多
文摘AA5083 friction stir welds were produced using systematic experimental design, the process forces and heat input with varying parameters were studied. Helpful empirical models were developed in designing friction stir welding （FSW） tools and FSW welders. These models may be further helpful for making process parameter choice for this sort of alloy, defining welding program and control of process parameters by using computer numerical control friction stir welding welders. The results show that tool rotational speed, welding speed and tool shoulder diameter are most significant parameters affecting axial force and heat input, while longitudinal force is significantly affected by welding speed and probe diameter.
基金Financial assistance from Defence Research and Development Organization(DRDO)
文摘The heat treatable aluminum-copper alloy AA2014 finds wide application in the aerospace and defence industry due to its high strength-toweight ratio and good ductility. Friction stir welding(FSW) process, an emerging solid state joining process, is suitable for joining this alloy compared to fusion welding processes. This work presents the formulation of a mathematical model with process parameters and tool geometry to predict the responses of friction stir welds of AA 2014-T6 aluminum alloy, viz yield strength, tensile strength and ductility. The most influential process parameters considered are spindle speed, welding speed, tilt angle and tool pin profile. A four-factor, five-level central composite design was used and a response surface methodology(RSM) was employed to develop the regression models to predict the responses.The mechanical properties, such as yield strength(YS), ultimate tensile strength(UTS) and percentage elongation(%El), are considered as responses. Method of analysis of variance was used to determine the important process parameters that affect the responses. Validation trials were carried out to validate these results. These results indicate that the friction stir welds of AA 2014-T6 aluminum alloy welded with hexagonal tool pin profile have the highest tensile strength and elongation, whereas the joints fabricated with conical tool pin profile have the lowest tensile strength and elongation.
基金The Natural Science Foundation of Jiangsu Province(No.BK20151485)
文摘The full-scale application of Tx-1, a multifunctional microbial agent, was carried out for 8 months in an anoxic/oxic（A/O） municipal wastewater treatment process. The results show that the Tx-1 dosed system can obtain good effluent characteristics while minimizing sludge production and energy consumption. The total phosphorus（TP） is lower than0. 5 mg/L in effluent without any chemical regent added. The discharged dry sludge per 10 000 m^3 wastewater Dwat decreases from 1. 4 to 0. 5 t. For per cubic meter wastewater, the air supply decreases from 6. 0 to 5. 1 m^3 and the electricity consumption decreases from 0. 412- 0. 425 kW·h to 0. 331 kW·h. The addition of Tx-1 can improve the substrate removal constant and decrease the microorganism growth yield coefficient of activated sludge. At the same time,the structure of the microbial community changes and the biodiversity increases by adding Tx-1. The abundance of polyphosphate accumulating organisms（PAO）, Comamonadaceae and Tetrasphaera, increased. Effective microbial agent is a potential way to combine in-situ sludge minimization with contaminants removal.
基金support provided by Boeing India to Indian Institute of Technology Kanpur,IndiaTEQIP funding from Government of India provided to G.B.Pant Institute of Engineering&Technology Pauri-Garhwal India
文摘This paper reports a novel micro-blast driven manufacturing process for micro-forming of Aluminum foils. The micro-blast is realized by using a nanoenergetic material system comprising of Bi_2O_3 microrods and aluminum particles. There is an enhanced need of forming of thin aluminum foil structures in small regions from point of view of drug packaging etc. The process developed caters to this need by using a single shot forming process using a micro-blast source. The micro-blast that is generated from an energetic composite system is made highly tunable by modulating the peak pressure generated through the blasting process and their impact in micro-forming of thin aluminum foils is observed through parametric studies. The engineering challenge involved in these experiments is to tune the blast pressure properties in order to address the forming of thin metal sheets with limiting boundary values as defined by the failure criteria. A variety of characterization techniques related to a thorough analysis of the synthesized material viz. X-ray diffraction(XRD), Scanning Electron Microscopy(SEM) etc, are used to tune the functional properties like gauge blast pressure etc, of material system. We have found a material system that can generate a maximum peak pressure of 73.8 MPa with pressurization rate of 2460 GPas^(-1) and that is able to accomplish micro-forming on thin metal foils(around 0.3 mm thickness). Experimental investigations demonstrate that tunabilty aspect of the energetic composites when exercised can enable variant processes such as embossing, coining, drilling etc. which may be of significant utility to drug packaging industries. A proper mathematical modeling of the forming process and critical process parameters therein have also been detailed.
基金financially supported by the Innovation Research Team Program of the Ministry of Education(IRT0713)the Key Laboratory of New Materials in Automobile of Liaoning Province(grant No.201016201)Doctoral Initiating Project of Liaoning Province Foundation for Natural Sciences,China
文摘In present study, BP neural network model was proposed for the prediction of ultimate compressive strength of Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting. The inputs of the BP neural network model were the applied load on the epispastic polystyrene template （F）, centrifugal acceleration （v） and sintering temperature （T）, while the only output was the ultimate compressive strength （（7）. According to the registered BP model, the effects of F, v, T on 0 were analyzed. The predicted results agree with the actual data within reasonable experimental error, indicating that the BP model is practically a very useful tool in property prediction and process parameter design of the Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting.
