This paper presents a detailed experimental and numerical study of aerodynamically produced noise which occurs due to turbulent structures created by the cowl cavity and side mirror. Measurements were carried out at V...This paper presents a detailed experimental and numerical study of aerodynamically produced noise which occurs due to turbulent structures created by the cowl cavity and side mirror. Measurements were carried out at Volvo aerodynamical wind tunnel on a Volvo XC60 production model. The configurations considered here are: side mirror On/Off with the cowl cavity open/closed. The results of exterior sound source mapping (with the intensity probe placed in the flow stream) have been compared with the results of the measurements inside the car. The contribution of the cowl area to overall wind noise level is measured in terms of AI% (Articulation Index) inside the compartment. It was shown that increase in AI by 2% could be attributed to the cowl generated wind noise. Transient numerical simulations of the turbulent flow around the car have been performed for all configurations. The results of the simulations show similarity to experimental results and give insight to the flow structures around the car.展开更多
The wheel loads of heavy trucks are the major source of pavement damage,given the repeated loadings imposed by them due to transient events and surface irregularities.While related studies focus on steady-state contex...The wheel loads of heavy trucks are the major source of pavement damage,given the repeated loadings imposed by them due to transient events and surface irregularities.While related studies focus on steady-state context regarding simplified vehicle’s parameters and ideal pavement conditions,this paper aims to analyze the vertical load applied to the pavement by considering cornering maneuver as a transient event,on a battery electric vehicle truck.In this concern,measurements were performed on a rigid truck,with two steering front axles,in a closed course proving ground.The relationship has been presented between vehicle’s speed,lateral acceleration and transferred vertical load for a given curve radius of 85.6 m and 3.7°of transversal slope.The measurements results indicated that for every 10 km/h increasing on the vehicle’s speed,additional 110 kgf will be transferred to the pavement on the outer side of the cornering radius.This value itself could not be considered high,but it will be also added to the static load,or overload in some truck applications.展开更多
Magnesium alloys remain critical in the context of light-weighting and advanced devices. The increased utilisation of magnesium(Mg)each year reveals growing demand for its Mg-based alloys. Additive manufacturing(AM) p...Magnesium alloys remain critical in the context of light-weighting and advanced devices. The increased utilisation of magnesium(Mg)each year reveals growing demand for its Mg-based alloys. Additive manufacturing(AM) provides the possibility to directly manufacture components in net-shape, providing new possibilities and applications for the use of Mg-alloys, and new prospects in the utilisation of novel physical structures made possible from ‘3D printing’. The review herein seeks to holistically explore the additive manufacturing of Mg-alloys to date, including a synopsis of processes used and properties measured(with a comparison to conventionally prepared Mg-alloys). The challenges and possibilities of AM Mg-alloys are critically elaborated for the field of mechanical metallurgy.展开更多
In nature, cellulose, lignocellulose and lignin are major sources of plant biomass; their recycling is indispensable for global carbon cycle. The major portion of the municipal solid waste consists of lignocellulose. ...In nature, cellulose, lignocellulose and lignin are major sources of plant biomass; their recycling is indispensable for global carbon cycle. The major portion of the municipal solid waste consists of lignocellulose. The incineration of organic fraction of municipal solid waste (OFMSW) with high moisture content and low calorific value is not environmentally, techno-commercially viable option for energy recovery. Optimization of biomethanisation process is aim to maximize organic waste stabilization at short digestion period with higher energy recovery. The biomethanisation studies, demonstrate co-digestion of substrates improves CH4 yield due to nutrients balance. Fungi are low sensitive to environment, thrive in acidic environment and produces required multi-enzyme, attach to cell envelope and hydrolyze the substrate for energy recovery. Fermentation of cellulose by the monoculture results in the formation of H2, CO2, formate, acetate, lactate, succinate, and ethanol. In co-cultures with Methanobacterium, H2 and formate reduction indicates it's utilized in CH4 production. Engineered co-culture of microorganisms is essential for the heterogeneous complex organic substrate degradation for extraction of unutilized energy fraction of biomass, as potential source of energy.展开更多
文摘This paper presents a detailed experimental and numerical study of aerodynamically produced noise which occurs due to turbulent structures created by the cowl cavity and side mirror. Measurements were carried out at Volvo aerodynamical wind tunnel on a Volvo XC60 production model. The configurations considered here are: side mirror On/Off with the cowl cavity open/closed. The results of exterior sound source mapping (with the intensity probe placed in the flow stream) have been compared with the results of the measurements inside the car. The contribution of the cowl area to overall wind noise level is measured in terms of AI% (Articulation Index) inside the compartment. It was shown that increase in AI by 2% could be attributed to the cowl generated wind noise. Transient numerical simulations of the turbulent flow around the car have been performed for all configurations. The results of the simulations show similarity to experimental results and give insight to the flow structures around the car.
文摘The wheel loads of heavy trucks are the major source of pavement damage,given the repeated loadings imposed by them due to transient events and surface irregularities.While related studies focus on steady-state context regarding simplified vehicle’s parameters and ideal pavement conditions,this paper aims to analyze the vertical load applied to the pavement by considering cornering maneuver as a transient event,on a battery electric vehicle truck.In this concern,measurements were performed on a rigid truck,with two steering front axles,in a closed course proving ground.The relationship has been presented between vehicle’s speed,lateral acceleration and transferred vertical load for a given curve radius of 85.6 m and 3.7°of transversal slope.The measurements results indicated that for every 10 km/h increasing on the vehicle’s speed,additional 110 kgf will be transferred to the pavement on the outer side of the cornering radius.This value itself could not be considered high,but it will be also added to the static load,or overload in some truck applications.
基金support from Australian National University Futures Schemethe support from the first Singapore-Germany Academic-Industry (2 + 2) international collaboration grant (Grant No.: A1890b0050)。
文摘Magnesium alloys remain critical in the context of light-weighting and advanced devices. The increased utilisation of magnesium(Mg)each year reveals growing demand for its Mg-based alloys. Additive manufacturing(AM) provides the possibility to directly manufacture components in net-shape, providing new possibilities and applications for the use of Mg-alloys, and new prospects in the utilisation of novel physical structures made possible from ‘3D printing’. The review herein seeks to holistically explore the additive manufacturing of Mg-alloys to date, including a synopsis of processes used and properties measured(with a comparison to conventionally prepared Mg-alloys). The challenges and possibilities of AM Mg-alloys are critically elaborated for the field of mechanical metallurgy.
文摘In nature, cellulose, lignocellulose and lignin are major sources of plant biomass; their recycling is indispensable for global carbon cycle. The major portion of the municipal solid waste consists of lignocellulose. The incineration of organic fraction of municipal solid waste (OFMSW) with high moisture content and low calorific value is not environmentally, techno-commercially viable option for energy recovery. Optimization of biomethanisation process is aim to maximize organic waste stabilization at short digestion period with higher energy recovery. The biomethanisation studies, demonstrate co-digestion of substrates improves CH4 yield due to nutrients balance. Fungi are low sensitive to environment, thrive in acidic environment and produces required multi-enzyme, attach to cell envelope and hydrolyze the substrate for energy recovery. Fermentation of cellulose by the monoculture results in the formation of H2, CO2, formate, acetate, lactate, succinate, and ethanol. In co-cultures with Methanobacterium, H2 and formate reduction indicates it's utilized in CH4 production. Engineered co-culture of microorganisms is essential for the heterogeneous complex organic substrate degradation for extraction of unutilized energy fraction of biomass, as potential source of energy.