Limited research has explored roadside advertisements’ effects on road user behavior in Middle Eastern countries. This study aims to understand distraction perceptions, including advertisements, their impact on behav...Limited research has explored roadside advertisements’ effects on road user behavior in Middle Eastern countries. This study aims to understand distraction perceptions, including advertisements, their impact on behavior, and potential influences from advertisement type, in-vehicle distraction, and country factors (reflecting culture and environment). A standardized questionnaire was administered in Jordan and Kuwait, complemented by observations across three segment types: roadside advertisements, commercial signs, and road signs as control segments. Descriptive and inferential statistics were used. Results indicated a significant disparity in distraction perception between the two groups. Advertisement presence influenced Kuwaiti but not Jordanian behavior. Behavior varied by advertisement type in Jordan, not Kuwait, and in-vehicle distraction did not impact driver behavior. The study suggests explicitly revising advertising policies with a traffic safety focus. Overall, the study contributes insights into road user perceptions and behaviors, highlighting the complex interplay of distractions and advertising on road safety. Further research is required to validate these findings and shape road safety regulations.展开更多
A higher cooling load is required with an increasing room temperature that resulted from the high thermal conductivity and low time lag of conventional construction materials[1].Such a high cooling load in...A higher cooling load is required with an increasing room temperature that resulted from the high thermal conductivity and low time lag of conventional construction materials[1].Such a high cooling load increases the carbon footprint from the energy consumption during building performance.The condition can be worsened with the urban heat island phenomenon,as the cooling load prolongs to night time for maintaining indoor thermal comfort.展开更多
The aim of the study is to comparatively assess the concentrations of lead, zinc and iron in Rivers Ase, Warri and Ethiope, in Nigeria. Monthly water samples were collected from six randomly selected sites along the r...The aim of the study is to comparatively assess the concentrations of lead, zinc and iron in Rivers Ase, Warri and Ethiope, in Nigeria. Monthly water samples were collected from six randomly selected sites along the rivers course. 72 water samples were collected from each river at 0 - 15 cm depths. Samples were analysed based on the standard methods recommended by the WHO for testing lead, zinc and iron. The assessment of the water quality was done using the Water Quality Index (WQI) of the Canadian Council of Ministers of the Environment (CCME-WQI). While hypotheses were tested using ANOVA. Findings indicated that CCME-WQI values were 47.3, 66.52 and 78.7. This meant that the water quality of River Ase is impaired and departed from desirable levels, while that of Warri and Ethiope were considered to occasionally be impaired and depart from desirable levels. The ANOVA model showed that there is a significant variation in heavy metal load in the selected rivers at P < 0.05. River water was put to domestic uses such as drinking (20.5%) preparing food (17.8%), bathing (19.8%), washing clothes and dishes (21.3%), brushing teeth (13.3%), and catering for domestic animals (7.5%). Poverty (49.5%) was the major reason for the use of river water for domestic purposes. The locals highlighted that they usually suffer from cholera (26.8%), diarrhoea (25.8%), dysentery (24%) and typhoid (23.5%) as a result of using the river water. The study recommended routine monitoring of anthropogenic and geologic activities, testing of the water regularly amongst others.展开更多
Internal effects of the dynamic behaviors and nonlinear characteristics of a coupled fractional order hydropower generation system(HGS) are analyzed. A mathematical model of hydro-turbine governing system(HTGS) with r...Internal effects of the dynamic behaviors and nonlinear characteristics of a coupled fractional order hydropower generation system(HGS) are analyzed. A mathematical model of hydro-turbine governing system(HTGS) with rigid water hammer and hydro-turbine generator unit(HTGU) with fractional order damping forces are proposed. Based on Lagrange equations, a coupled fractional order HGS is established. Considering the dynamic transfer coefficient eis variational during the operation, introduced e as a periodic excitation into the HGS. The internal relationship of the dynamic behaviors between HTGS and HTGU is analyzed under different parameter values and fractional order. The results show obvious fast–slow dynamic behaviors in the HGS, causing corresponding vibration of the system, and some remarkable evolution phenomena take place with the changing of the periodic excitation parameter values.展开更多
This paper describes the physical model testing of a wave energy converter (WEC) undertaken in the Heriot-Watt wave basin during October 2010 as part of the SUPERGEN2 project funded by the British government,and provi...This paper describes the physical model testing of a wave energy converter (WEC) undertaken in the Heriot-Watt wave basin during October 2010 as part of the SUPERGEN2 project funded by the British government,and provides a preliminary analysis of the extreme mooring loads.Tests were completed at 1/20 scale on a single oscillating water column device deployed with a 3-line taut mooring configuration.The model was fully instrumented with mooring line load cells and an optical motion tracker.The tests were preceded by calibration of instrumentation and the wave test environment,and carried out in long crested waves regimes with 12 combinations of peak period T p and significant wave height H s.The main objective for these experiments was to examine the effect of shape and size of the tethered buoy on the leading mooring line on the maximum mooring loads and the excursion of the device.Comparison of the loads at different configurations of the tethered buoy suggests that the results are consistent with the hypothesis that the mooring forces should depend on the change in stiffness of the mooring system.In particular,the results indicate that with the spectral peak period close to the natural period of the moored device of 8 s,peak loads in a configuration with a smaller buoy may be considerably higher than those with a larger buoy.However,when T p was dissimilar,a harder mooring with a smaller spherical buoy appears to result in lower peak loads.The exact configuration should,therefore,be chosen according to the prevalent conditions of any particular location,and will also depend on the design and expected maintenance schedule,as well as matters related to the risk to navigation,environmental effects and the conservation status of the area.展开更多
The permafrost development in the Qinghai-Tibet Engineering Corridor(QTEC)is affected by natural environment changes and human engineering activities.Human engineering activities may damage the permafrost growing envi...The permafrost development in the Qinghai-Tibet Engineering Corridor(QTEC)is affected by natural environment changes and human engineering activities.Human engineering activities may damage the permafrost growing environment,which in turn impact these engineering activities.Thus high spatial-temporal resolution monitoring over the QTEC in the permafrost region is very necessary.This paper presents a method for monitoring the frozen soil area using the intermittent coherencebased small baseline subset(ICSBAS).The method can improve the point density of the results and enhance the interpretability of deformation results by identifying the discontinuous coherent points according to the coherent value of time series.Using the periodic function that models the seasonal variation of permafrost,we separate the long wavelength atmospheric delay and establish an estimation model for the frozen soil deformation.Doing this can raise the monitoring accuracy and improve the understanding of the surface deformation of the frozen soil.In this study,we process 21 PALSAR data acquired by the Alos satellite with the proposed ICSBAS technique.The results show that the frozen soil far from the QTR in the study area experiences frost heave and thaw settlement(4.7 cm to8.4 cm)alternatively,while the maximum settlement along the QTR reaches 12 cm.The interferomatric syntnetic aperture radar(InSAR)-derived results are validated using the ground leveling data nearby the Beiluhe basin.The validation results show the InSAR results have good consistency with the leveling data in displacement rates as well as time series.We also find that the deformation in the permafrost area is correlated with temperature,human activities and topography.Based on the interfering degree of human engineering activities on the permafrost environment,we divide the QTEC along the Qinghai-Tibet Railway into engineering damage zone,transition zone and natural permafrost.展开更多
This study investigated the practice and perceptions on waste management and the feasibility of establishing a site waste management plan in the Zambian Construction Industry (ZCI). In this research, Lusaka and the Co...This study investigated the practice and perceptions on waste management and the feasibility of establishing a site waste management plan in the Zambian Construction Industry (ZCI). In this research, Lusaka and the Copperbelt provinces were selected as study areas to represent the construction industry in Zambia. This was because the largest volume of construction work in the country is mainly concentrated in these two provinces. The research targeted contractors from Grades 1 to 3 as categorised and registered by the Zambian National Council for Construction (NCC). Consultancy firms and government institutions were also included in the target population as regulators. Data for this study were obtained through questionnaires, interviews and site surveys. The results from this research indicated that disposal was the most common method of waste management in the Zambian Construction industry as indicated by the highest ranking score with a mean index of 0.923. The research concluded that the construction industry in Zambia has poor practice of waste management through waste disposal which is not environmentally friendly. The results further indicated that it is feasible to adopt a Site Waste Management Plan in the Zambian Construction industry based on the respondents’ willingness mean score of 0.94 from all the categories. Finally, the research confirmed that a Site Waste Management Plan can be an effective tool to address waste management challenges in the Zambian Construction Industry based on the literature review and willingness measured from research respondents.展开更多
The little stiffness modulus, high voidage and long curing time has limited the use of CBEM's (cold bituminous emulsion mixtures) in road and highways to pavement experiencing low traffic. The aim of this study is ...The little stiffness modulus, high voidage and long curing time has limited the use of CBEM's (cold bituminous emulsion mixtures) in road and highways to pavement experiencing low traffic. The aim of this study is to improve the properties of gap graded CRA (cold rolled asphal0 containing OPC (ordinary portland cement) as filler by addition of a by-product material as an activator. OPC was added to the CRA as a replacement to the conventional mineral filler (0%-100%), while LJMUA (Liverpool John Moores University Activator) was added as an additive in the range from 0%-3% by total mass of aggregate. Laboratory tests included stiffness modulus and uniaxial creep test to assess the mechanical properties. The results have shown a considerable improvement in the mechanical properties from the addition of LJMUA to the CRA containing OPC especially for the early life stiffness modulus that is the main disadvantage of the cold mixtures.展开更多
Very high concentration of flexural, shear and torsional stresses occurs at the wall-slab junctions in a laterally loaded tall building consisting of planar walls and coupling slabs. Due to this concentration of stres...Very high concentration of flexural, shear and torsional stresses occurs at the wall-slab junctions in a laterally loaded tall building consisting of planar walls and coupling slabs. Due to this concentration of stresses and their interaction, there are great chances of failure to occur at the junction. Also the flexural stresses are not uniformly distributed and have the highest intensity near the periphery of inner walls but are reduced drastically as we move away from the wall-slab junction. Numerous attempts have been made to strengthen the wall-slab junction by using various types of shear reinforcement to ensure that shear failure should not occur. Various methods including fibre reinforcement consisting of twins of twisted steel couplets have already been used. This paper describes a new method of placing 2 inch wide flange I-sections at appropriate locations to improve the shear strength of the wall-slab junctions. Based on systematic research, a new procedure has also been developed to assess the strength of wall-slab junction using the new reinforcement method. Test results showed that a substantial increase, up to 57%, in the shear strength of specimens was obtained by using the new method of shear reinforcement in a laterally loaded tall building.展开更多
The COVID-19 virus is usually spread by small droplets when talking,coughing and sneezing,so maintaining physical distance between people is necessary to slow the spread of the virus.The World Health Organization(WHO)...The COVID-19 virus is usually spread by small droplets when talking,coughing and sneezing,so maintaining physical distance between people is necessary to slow the spread of the virus.The World Health Organization(WHO)recommends maintaining a social distance of at least six feet.In this paper,we developed a real-time pedestrian social distance risk alert system for COVID-19,whichmonitors the distance between people in real-time via video streaming and provides risk alerts to the person in charge,thus avoiding the problem of too close social distance between pedestrians in public places.We design a lightweight convolutional neural network architecture to detect the distance between people more accurately.In addition,due to the limitation of camera placement,the previous algorithm based on flat view is not applicable to the social distance calculation for cameras,so we designed and developed a perspective conversion module to reduce the image in the video to a bird’s eye view,which can avoid the error caused by the elevation view and thus provide accurate risk indication to the user.We selected images containing only person labels in theCOCO2017 dataset to train our networkmodel.The experimental results show that our network model achieves 82.3%detection accuracy and performs significantly better than other mainstream network architectures in the three metrics of Recall,Precision and mAP,proving the effectiveness of our system and the efficiency of our technology.展开更多
Changing climate intensifies heat stress,resulting in a greater risk of workplace productivity decline in timber office buildings with low internal thermal mass.The impact of climate change induced heat exposure on in...Changing climate intensifies heat stress,resulting in a greater risk of workplace productivity decline in timber office buildings with low internal thermal mass.The impact of climate change induced heat exposure on indoor workplace productivity in timber office buildings has not been extensively researched.Therefore,further investigation to reduce the work capacity decline towards the end of the century is needed.Here,heat exposure in a net zero-carbon timber building near Brussels,Belgium,was evaluated using a reproducible comparative approach with different internal thermal mass levels.The analysis indicated that strategies with increased thermal mass were more effective in limiting the effects of heat exposure on workplace productivity.The medium and high thermal mass strategies reduced workplace productivity loss to 0.1%in the current,0.3%and 0.2%in the midfuture,and 4.9%and 3.9%for future scenarios.In comparison,baseline with low thermal mass yielded a decline of 2.3%,3.3%,and 8.2%.The variation in maximum and minimum wet-bulb globe temperatures were also lower for medium and high thermal mass strategies than for low thermal mass baseline.The study findings lead to the formulation of design guidelines,identification of research gaps,and recommendations for future work.展开更多
Severe urban heat,a prevalent climate change consequence,endangers city residents globally.Vegetation-based mitigation strategies are commonly employed to address this issue.However,the Middle East and North Africa ar...Severe urban heat,a prevalent climate change consequence,endangers city residents globally.Vegetation-based mitigation strategies are commonly employed to address this issue.However,the Middle East and North Africa are under investigated in terms of heat mitigation,despite being one of the regions most vulnerable to climate change.This study assesses the feasibility and climatic implications of wide-scale implementation of green infrastructure(GI)for heat mitigation in Riyadh,Saudi Arabia—a representative desert city characterized by low vegetation coverage,severe summer heat,and drought.Weather research forecasting model(WRF)is used to simulate GI cooling measures in Riyadh’s summer condition,including measures of increasing vegetation coverage up to 60%,considering irrigation and vegetation types(tall/short).In Riyadh,without irrigation,increasing GI fails to cool the city and can even lead to warming(0.1 to 0.3℃).Despite irrigation,Riyadh’s overall GI cooling effect is 50% lower than GI cooling expectations based on literature meta-analyses,in terms of average peak hour temperature reduction.The study highlights that increased irrigation substantially raises the rate of direct soil evaporation,reducing the proportion of irrigation water used for transpiration and thus diminishing efficiency.Concurrently,water resource management must be tailored to these specific considerations.展开更多
In the context of escalating global energy demands,urban areas,specifically the building sector,contribute to the largest energy consumption,with urban overheating exacerbating this issue.Utilizing urban modelling for...In the context of escalating global energy demands,urban areas,specifically the building sector,contribute to the largest energy consumption,with urban overheating exacerbating this issue.Utilizing urban modelling for heat-mitigation and reduction of energy demand is crucial steps towards a sustainable built-environment,complementing onsite energy generation in the design and development of Net-zero Energy(NZE)Settlement,especially in the context of Australian weather conditions.Addressing a significant gap in existing literature,this study offers empirical analysis on the climate and energy efficacy of integrated heat mitigation strategies applied in 14 neighbourhood typologies located in Sydney,Australia.Examining the application of cool materials on roads,pavements,and rooftops,alongside urban vegetation enhancement,the analysis demonstrates scenario effectiveness on heat mitigation that leads to reduce ambient temperature and energy demands along with CO_(2)emissions within the neighbourhoods.Considering building arrangement,built-area ratio,building height,and locations,ENVI-met and CitySim are utilized to assess the heat-mitigation and the energy demand of neighbourhoods,respectively.Results indicate that mitigation measures can lead up to a 2.71℃reduction in ambient temperature and over 25%reduction in Cooling Degree Hours,with a 34.34%reduction in cooling energy demand and overall energy savings of up to 12.49%.In addition,the annual energy-saving yields a CO_(2)reduction of approximately 141.12 tonnes,where additional vegetation further amplifies these reductions by enhancing CO_(2)absorption.This study showcases the pathway towards achieving NZE goals in climates similar to that of Australia,highlighting significant benefits in heat-mitigation,environmental impact,and energy-savings.展开更多
Performance of Photovoltaic-double skin façade(Photovoltaic-DSF)system in summer has been critical.Owing to high solar ingress,cooling requirement of a building significantly increases.Photovoltaic-DSF system pro...Performance of Photovoltaic-double skin façade(Photovoltaic-DSF)system in summer has been critical.Owing to high solar ingress,cooling requirement of a building significantly increases.Photovoltaic-DSF system provides a shield and controls the heat gain through fenestration in the interior spaces.In the present article,mathematical correlations are developed for energy characterization of forced-ventilated Photovoltaic-DSF system in India’s hot summer zone i.e.Jaipur.The Photovoltaic-DSF system has been installed and monitored for Jaipur’s summer months(May to July).L25 Orthogonal array of design parameters(air cavity thickness,air velocity,and PV panel’s transparency)and their respective levels have been developed using Taguchi design to perform experiments.Based on experimental results,multiple linear regression has been used to forecast solar heat gain coefficient,PVs electrical power and daylighting illuminance indoors as function of design factors.The statistical significance of mathematical relationships is sorted by variance analysis,which is found to be in good accord with field measurements(R2>0.90).The proposed correlations are pragmatic in designing Photovoltaic-DSF systems for hot summer conditions.The Photovoltaic-DSF system with 30%transmittance and air velocity of 5 metres per second in 200 mm air cavity thickness achieved maximum energy performance in hot summers.展开更多
Railways are very important to our society due to their efficiency and reduced environmental effects.A system for the measurement of the condition of the formation on which a permanent way(pairs of rails laid on sleep...Railways are very important to our society due to their efficiency and reduced environmental effects.A system for the measurement of the condition of the formation on which a permanent way(pairs of rails laid on sleepers)is located is investigated in this work.This will allow effective asset management and reduce the costs of rail maintenance.Areas where the formation is either weak or changes rapidly present problems when maintaining a section of the track due to poor track geometry.Formation stiffness is a difficult parameter to measure and requires extensive research efforts.In this work a train-track interaction problem is investigated with a quarter train track model,which consists of a coach,bogie and wheel.The train-irregularity model is developed which computes the train response to irregularities,such as the deflection by stiffness changes.Using this train–irregularity model,the effects of train speed on the wheel/rail interaction force over the stiffness changes are studied and the track stiffness is also analysed,which will be used in future analysis to calculate the actual stiffness of the track when using laser measurement techniques.展开更多
Waste biomass is always generated during the production process in industries. The ordinary way to get rid of the waste biomass is to send them to landfill or burn it in the open field. The waste may potentially be us...Waste biomass is always generated during the production process in industries. The ordinary way to get rid of the waste biomass is to send them to landfill or burn it in the open field. The waste may potentially be used for co-firing with coal to save fossil fuel consumption and also reduce net carbon emissions. In this case study, the bio-waste from a Nicotiana Tahacum (NT) pre-treatment plant is used as the biomass to co-fire with coal. The samples of NT wastes were analysed. It was found that the wastes were of the relatively high energy content which were suitable for co-firing with coal. To investigate the potential and benefits for adding NT wastes to a Fluidised Bed Combustion (FBC) boiler in the plant, detailed modelling and simulation are carried out using the European Coal Liquefaction Process Simulation and Evaluation (ECLIPSE) process simulation package. The feedstock blending ratios of NT waste to coal studied in this work are varied from 0% to 30%. The results show that the addition of NT wastes may decrease the emissions of CO2 and SOx without reducing the boiler performance.展开更多
It is possible for cost professionals to prepare an informed and compendious cost plan by identifying all the factors that cause cost overruns,variations,safety hazards and others without having a significant pr...It is possible for cost professionals to prepare an informed and compendious cost plan by identifying all the factors that cause cost overruns,variations,safety hazards and others without having a significant prior experience.The implementation of Extended Reality can address this phenomenon.The paper aims to introduce the concept of Extended Reality in the field of quantity surveying by exploring its untapped potential and also looks to identify critical barriers in implementing this technology.A detailed review of literature study produced eight critical factors acting as barriers in successful implementation.With the suggestions from the industry professionals,the inter-relationship among these factors were established and prioritised using Interpretative Structural Modelling(ISM)tool.Further,these factors were categorised using MICMAC(Cross-Impact Matrix Multiplication Applied to Classification)analysis.This study identifies,lack of expertise and lack of suitable software as the key driving factors in successful implementation and all the remaining factors are directly or indirectly influenced by them.The sample size considered in building the ISM network is limited to the Indian construction industry.The disadvantages of Extended Reality have not been covered in the study.There may be several negative repercussions to human health due to this technology.This study can be used by industry professionals in understanding how advance technology like this can overcome many challenges pertinent to cost planning and estimation.This study stands out among the few research topics which contribute to reducing the knowledge gap among the cost professionals irrespective of their experience.展开更多
For the past 50 years,the Sydney Opera House has been the subject of a prodigious hagiography of the personalities involved in its realization and their legendary querelles.Yet it remains paradoxically unexplored when...For the past 50 years,the Sydney Opera House has been the subject of a prodigious hagiography of the personalities involved in its realization and their legendary querelles.Yet it remains paradoxically unexplored when it comes to its operative construction decisions,particularly those that relate to the erection of its renowned superstructure.Through the analysis of a newly discovered set of shop drawings prepared for the innovative formwork system of the iconic roof sails,the paper contributes to the construction history of the building whilst shedding light on the hitherto unacknowledged role of the general contractor in the design process.In doing so,it questions the validity of conventional assumptions about the technical division of labour in complex projects,where construction and project management tend to be kept separate from architectural and structural design,furthermore suggesting the need for broader design exegeses,combining project-based and production-based concerns.In reflecting on its import for contemporary practice,the study suggests that the revealing picture of the Sydney Opera House project,as it emerged from the cumbersome archive-based crossanalysis of the manual documentation produced for it,is in principle much easier and perhaps important to obtain today.This is due,on the one side,to availability and diffusion of digital project collaborative platforms;on the other side,to the merging and the blurring of professional and non-professional design contributions.展开更多
文摘Limited research has explored roadside advertisements’ effects on road user behavior in Middle Eastern countries. This study aims to understand distraction perceptions, including advertisements, their impact on behavior, and potential influences from advertisement type, in-vehicle distraction, and country factors (reflecting culture and environment). A standardized questionnaire was administered in Jordan and Kuwait, complemented by observations across three segment types: roadside advertisements, commercial signs, and road signs as control segments. Descriptive and inferential statistics were used. Results indicated a significant disparity in distraction perception between the two groups. Advertisement presence influenced Kuwaiti but not Jordanian behavior. Behavior varied by advertisement type in Jordan, not Kuwait, and in-vehicle distraction did not impact driver behavior. The study suggests explicitly revising advertising policies with a traffic safety focus. Overall, the study contributes insights into road user perceptions and behaviors, highlighting the complex interplay of distractions and advertising on road safety. Further research is required to validate these findings and shape road safety regulations.
文摘A higher cooling load is required with an increasing room temperature that resulted from the high thermal conductivity and low time lag of conventional construction materials[1].Such a high cooling load increases the carbon footprint from the energy consumption during building performance.The condition can be worsened with the urban heat island phenomenon,as the cooling load prolongs to night time for maintaining indoor thermal comfort.
文摘The aim of the study is to comparatively assess the concentrations of lead, zinc and iron in Rivers Ase, Warri and Ethiope, in Nigeria. Monthly water samples were collected from six randomly selected sites along the rivers course. 72 water samples were collected from each river at 0 - 15 cm depths. Samples were analysed based on the standard methods recommended by the WHO for testing lead, zinc and iron. The assessment of the water quality was done using the Water Quality Index (WQI) of the Canadian Council of Ministers of the Environment (CCME-WQI). While hypotheses were tested using ANOVA. Findings indicated that CCME-WQI values were 47.3, 66.52 and 78.7. This meant that the water quality of River Ase is impaired and departed from desirable levels, while that of Warri and Ethiope were considered to occasionally be impaired and depart from desirable levels. The ANOVA model showed that there is a significant variation in heavy metal load in the selected rivers at P < 0.05. River water was put to domestic uses such as drinking (20.5%) preparing food (17.8%), bathing (19.8%), washing clothes and dishes (21.3%), brushing teeth (13.3%), and catering for domestic animals (7.5%). Poverty (49.5%) was the major reason for the use of river water for domestic purposes. The locals highlighted that they usually suffer from cholera (26.8%), diarrhoea (25.8%), dysentery (24%) and typhoid (23.5%) as a result of using the river water. The study recommended routine monitoring of anthropogenic and geologic activities, testing of the water regularly amongst others.
基金Project supported by the National Natural Science Foundation of China for Outstanding Youth(Grant No.51622906)the National Natural Science Foundation of China(Grant No.51479173)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.201304030577)the Scientific Research Funds of Northwest A&F University(Grant No.2013BSJJ095)the Science Fund for Excellent Young Scholars from Northwest A&F University and Shaanxi Nova Program,China(Grant No.2016KJXX-55)
文摘Internal effects of the dynamic behaviors and nonlinear characteristics of a coupled fractional order hydropower generation system(HGS) are analyzed. A mathematical model of hydro-turbine governing system(HTGS) with rigid water hammer and hydro-turbine generator unit(HTGU) with fractional order damping forces are proposed. Based on Lagrange equations, a coupled fractional order HGS is established. Considering the dynamic transfer coefficient eis variational during the operation, introduced e as a periodic excitation into the HGS. The internal relationship of the dynamic behaviors between HTGS and HTGU is analyzed under different parameter values and fractional order. The results show obvious fast–slow dynamic behaviors in the HGS, causing corresponding vibration of the system, and some remarkable evolution phenomena take place with the changing of the periodic excitation parameter values.
基金Funded by the UK Engineering and Physical Sciences Research Council under the grant EP/E040136/1
文摘This paper describes the physical model testing of a wave energy converter (WEC) undertaken in the Heriot-Watt wave basin during October 2010 as part of the SUPERGEN2 project funded by the British government,and provides a preliminary analysis of the extreme mooring loads.Tests were completed at 1/20 scale on a single oscillating water column device deployed with a 3-line taut mooring configuration.The model was fully instrumented with mooring line load cells and an optical motion tracker.The tests were preceded by calibration of instrumentation and the wave test environment,and carried out in long crested waves regimes with 12 combinations of peak period T p and significant wave height H s.The main objective for these experiments was to examine the effect of shape and size of the tethered buoy on the leading mooring line on the maximum mooring loads and the excursion of the device.Comparison of the loads at different configurations of the tethered buoy suggests that the results are consistent with the hypothesis that the mooring forces should depend on the change in stiffness of the mooring system.In particular,the results indicate that with the spectral peak period close to the natural period of the moored device of 8 s,peak loads in a configuration with a smaller buoy may be considerably higher than those with a larger buoy.However,when T p was dissimilar,a harder mooring with a smaller spherical buoy appears to result in lower peak loads.The exact configuration should,therefore,be chosen according to the prevalent conditions of any particular location,and will also depend on the design and expected maintenance schedule,as well as matters related to the risk to navigation,environmental effects and the conservation status of the area.
基金supported by the National Natural Science Foundation of China(42174026)the National Key Research and Development Program of China(2021YFE011004)。
文摘The permafrost development in the Qinghai-Tibet Engineering Corridor(QTEC)is affected by natural environment changes and human engineering activities.Human engineering activities may damage the permafrost growing environment,which in turn impact these engineering activities.Thus high spatial-temporal resolution monitoring over the QTEC in the permafrost region is very necessary.This paper presents a method for monitoring the frozen soil area using the intermittent coherencebased small baseline subset(ICSBAS).The method can improve the point density of the results and enhance the interpretability of deformation results by identifying the discontinuous coherent points according to the coherent value of time series.Using the periodic function that models the seasonal variation of permafrost,we separate the long wavelength atmospheric delay and establish an estimation model for the frozen soil deformation.Doing this can raise the monitoring accuracy and improve the understanding of the surface deformation of the frozen soil.In this study,we process 21 PALSAR data acquired by the Alos satellite with the proposed ICSBAS technique.The results show that the frozen soil far from the QTR in the study area experiences frost heave and thaw settlement(4.7 cm to8.4 cm)alternatively,while the maximum settlement along the QTR reaches 12 cm.The interferomatric syntnetic aperture radar(InSAR)-derived results are validated using the ground leveling data nearby the Beiluhe basin.The validation results show the InSAR results have good consistency with the leveling data in displacement rates as well as time series.We also find that the deformation in the permafrost area is correlated with temperature,human activities and topography.Based on the interfering degree of human engineering activities on the permafrost environment,we divide the QTEC along the Qinghai-Tibet Railway into engineering damage zone,transition zone and natural permafrost.
文摘This study investigated the practice and perceptions on waste management and the feasibility of establishing a site waste management plan in the Zambian Construction Industry (ZCI). In this research, Lusaka and the Copperbelt provinces were selected as study areas to represent the construction industry in Zambia. This was because the largest volume of construction work in the country is mainly concentrated in these two provinces. The research targeted contractors from Grades 1 to 3 as categorised and registered by the Zambian National Council for Construction (NCC). Consultancy firms and government institutions were also included in the target population as regulators. Data for this study were obtained through questionnaires, interviews and site surveys. The results from this research indicated that disposal was the most common method of waste management in the Zambian Construction industry as indicated by the highest ranking score with a mean index of 0.923. The research concluded that the construction industry in Zambia has poor practice of waste management through waste disposal which is not environmentally friendly. The results further indicated that it is feasible to adopt a Site Waste Management Plan in the Zambian Construction industry based on the respondents’ willingness mean score of 0.94 from all the categories. Finally, the research confirmed that a Site Waste Management Plan can be an effective tool to address waste management challenges in the Zambian Construction Industry based on the literature review and willingness measured from research respondents.
文摘The little stiffness modulus, high voidage and long curing time has limited the use of CBEM's (cold bituminous emulsion mixtures) in road and highways to pavement experiencing low traffic. The aim of this study is to improve the properties of gap graded CRA (cold rolled asphal0 containing OPC (ordinary portland cement) as filler by addition of a by-product material as an activator. OPC was added to the CRA as a replacement to the conventional mineral filler (0%-100%), while LJMUA (Liverpool John Moores University Activator) was added as an additive in the range from 0%-3% by total mass of aggregate. Laboratory tests included stiffness modulus and uniaxial creep test to assess the mechanical properties. The results have shown a considerable improvement in the mechanical properties from the addition of LJMUA to the CRA containing OPC especially for the early life stiffness modulus that is the main disadvantage of the cold mixtures.
文摘Very high concentration of flexural, shear and torsional stresses occurs at the wall-slab junctions in a laterally loaded tall building consisting of planar walls and coupling slabs. Due to this concentration of stresses and their interaction, there are great chances of failure to occur at the junction. Also the flexural stresses are not uniformly distributed and have the highest intensity near the periphery of inner walls but are reduced drastically as we move away from the wall-slab junction. Numerous attempts have been made to strengthen the wall-slab junction by using various types of shear reinforcement to ensure that shear failure should not occur. Various methods including fibre reinforcement consisting of twins of twisted steel couplets have already been used. This paper describes a new method of placing 2 inch wide flange I-sections at appropriate locations to improve the shear strength of the wall-slab junctions. Based on systematic research, a new procedure has also been developed to assess the strength of wall-slab junction using the new reinforcement method. Test results showed that a substantial increase, up to 57%, in the shear strength of specimens was obtained by using the new method of shear reinforcement in a laterally loaded tall building.
基金This research was funded by the Fundamental Research Funds for the Central Universities,3072022TS0605the China University Industry-University-Research Innovation Fund,2021LDA10004.
文摘The COVID-19 virus is usually spread by small droplets when talking,coughing and sneezing,so maintaining physical distance between people is necessary to slow the spread of the virus.The World Health Organization(WHO)recommends maintaining a social distance of at least six feet.In this paper,we developed a real-time pedestrian social distance risk alert system for COVID-19,whichmonitors the distance between people in real-time via video streaming and provides risk alerts to the person in charge,thus avoiding the problem of too close social distance between pedestrians in public places.We design a lightweight convolutional neural network architecture to detect the distance between people more accurately.In addition,due to the limitation of camera placement,the previous algorithm based on flat view is not applicable to the social distance calculation for cameras,so we designed and developed a perspective conversion module to reduce the image in the video to a bird’s eye view,which can avoid the error caused by the elevation view and thus provide accurate risk indication to the user.We selected images containing only person labels in theCOCO2017 dataset to train our networkmodel.The experimental results show that our network model achieves 82.3%detection accuracy and performs significantly better than other mainstream network architectures in the three metrics of Recall,Precision and mAP,proving the effectiveness of our system and the efficiency of our technology.
基金the Service Public de Wallonie(SPW),Belgium,under BElgian WAllonia REsearch(BEWARE)fellowships and European Union(EU)framework program for research and innovation,Marie Skłodowska-Curie Actions(MSCA)through contract no.847587 for the Project SurChauffe.the U.S.Department of Energy,Office of Science,Office of Biological and Environmental Research’s Urban Integrated Field Laboratories research activity,under Award Number DE-SC0023520.+2 种基金the members of the School of Geographical Sciences and Urban Planning at Arizona State University,and Southwest Urban Corridor Integrated Field Laboratory(SW-IFL)for their support.We would also like to thank the stakeholders of Project OCCuPANt.the Sustainable Building Design Lab at the Faculty of Applied Sciences at the University of Liege for the valuable support and use of the state-of-the-art Super COmputeR ProcessIng wOrkstatioN(SCORPION)for building performance simulations and data analysis.the IEA EBC Annex 80-Resilient Cooling of Buildings.
文摘Changing climate intensifies heat stress,resulting in a greater risk of workplace productivity decline in timber office buildings with low internal thermal mass.The impact of climate change induced heat exposure on indoor workplace productivity in timber office buildings has not been extensively researched.Therefore,further investigation to reduce the work capacity decline towards the end of the century is needed.Here,heat exposure in a net zero-carbon timber building near Brussels,Belgium,was evaluated using a reproducible comparative approach with different internal thermal mass levels.The analysis indicated that strategies with increased thermal mass were more effective in limiting the effects of heat exposure on workplace productivity.The medium and high thermal mass strategies reduced workplace productivity loss to 0.1%in the current,0.3%and 0.2%in the midfuture,and 4.9%and 3.9%for future scenarios.In comparison,baseline with low thermal mass yielded a decline of 2.3%,3.3%,and 8.2%.The variation in maximum and minimum wet-bulb globe temperatures were also lower for medium and high thermal mass strategies than for low thermal mass baseline.The study findings lead to the formulation of design guidelines,identification of research gaps,and recommendations for future work.
文摘Severe urban heat,a prevalent climate change consequence,endangers city residents globally.Vegetation-based mitigation strategies are commonly employed to address this issue.However,the Middle East and North Africa are under investigated in terms of heat mitigation,despite being one of the regions most vulnerable to climate change.This study assesses the feasibility and climatic implications of wide-scale implementation of green infrastructure(GI)for heat mitigation in Riyadh,Saudi Arabia—a representative desert city characterized by low vegetation coverage,severe summer heat,and drought.Weather research forecasting model(WRF)is used to simulate GI cooling measures in Riyadh’s summer condition,including measures of increasing vegetation coverage up to 60%,considering irrigation and vegetation types(tall/short).In Riyadh,without irrigation,increasing GI fails to cool the city and can even lead to warming(0.1 to 0.3℃).Despite irrigation,Riyadh’s overall GI cooling effect is 50% lower than GI cooling expectations based on literature meta-analyses,in terms of average peak hour temperature reduction.The study highlights that increased irrigation substantially raises the rate of direct soil evaporation,reducing the proportion of irrigation water used for transpiration and thus diminishing efficiency.Concurrently,water resource management must be tailored to these specific considerations.
基金supported by the 2020 UNSW Scientia PhD Scholarship Scheme and carried out under the UNSW Scientia Project entitled“Energy Poverty in NSW.Characteristics,Impact and Solutions”.
文摘In the context of escalating global energy demands,urban areas,specifically the building sector,contribute to the largest energy consumption,with urban overheating exacerbating this issue.Utilizing urban modelling for heat-mitigation and reduction of energy demand is crucial steps towards a sustainable built-environment,complementing onsite energy generation in the design and development of Net-zero Energy(NZE)Settlement,especially in the context of Australian weather conditions.Addressing a significant gap in existing literature,this study offers empirical analysis on the climate and energy efficacy of integrated heat mitigation strategies applied in 14 neighbourhood typologies located in Sydney,Australia.Examining the application of cool materials on roads,pavements,and rooftops,alongside urban vegetation enhancement,the analysis demonstrates scenario effectiveness on heat mitigation that leads to reduce ambient temperature and energy demands along with CO_(2)emissions within the neighbourhoods.Considering building arrangement,built-area ratio,building height,and locations,ENVI-met and CitySim are utilized to assess the heat-mitigation and the energy demand of neighbourhoods,respectively.Results indicate that mitigation measures can lead up to a 2.71℃reduction in ambient temperature and over 25%reduction in Cooling Degree Hours,with a 34.34%reduction in cooling energy demand and overall energy savings of up to 12.49%.In addition,the annual energy-saving yields a CO_(2)reduction of approximately 141.12 tonnes,where additional vegetation further amplifies these reductions by enhancing CO_(2)absorption.This study showcases the pathway towards achieving NZE goals in climates similar to that of Australia,highlighting significant benefits in heat-mitigation,environmental impact,and energy-savings.
基金supported by a DST project named“Development and performance analysis of Semi-Transparent Solar Photovoltaic double pane Window/Facade system”funded by the Department of Science and Technology,Government of India (TMD/CERI/BEE/2016/070(G)).
文摘Performance of Photovoltaic-double skin façade(Photovoltaic-DSF)system in summer has been critical.Owing to high solar ingress,cooling requirement of a building significantly increases.Photovoltaic-DSF system provides a shield and controls the heat gain through fenestration in the interior spaces.In the present article,mathematical correlations are developed for energy characterization of forced-ventilated Photovoltaic-DSF system in India’s hot summer zone i.e.Jaipur.The Photovoltaic-DSF system has been installed and monitored for Jaipur’s summer months(May to July).L25 Orthogonal array of design parameters(air cavity thickness,air velocity,and PV panel’s transparency)and their respective levels have been developed using Taguchi design to perform experiments.Based on experimental results,multiple linear regression has been used to forecast solar heat gain coefficient,PVs electrical power and daylighting illuminance indoors as function of design factors.The statistical significance of mathematical relationships is sorted by variance analysis,which is found to be in good accord with field measurements(R2>0.90).The proposed correlations are pragmatic in designing Photovoltaic-DSF systems for hot summer conditions.The Photovoltaic-DSF system with 30%transmittance and air velocity of 5 metres per second in 200 mm air cavity thickness achieved maximum energy performance in hot summers.
文摘Railways are very important to our society due to their efficiency and reduced environmental effects.A system for the measurement of the condition of the formation on which a permanent way(pairs of rails laid on sleepers)is located is investigated in this work.This will allow effective asset management and reduce the costs of rail maintenance.Areas where the formation is either weak or changes rapidly present problems when maintaining a section of the track due to poor track geometry.Formation stiffness is a difficult parameter to measure and requires extensive research efforts.In this work a train-track interaction problem is investigated with a quarter train track model,which consists of a coach,bogie and wheel.The train-irregularity model is developed which computes the train response to irregularities,such as the deflection by stiffness changes.Using this train–irregularity model,the effects of train speed on the wheel/rail interaction force over the stiffness changes are studied and the track stiffness is also analysed,which will be used in future analysis to calculate the actual stiffness of the track when using laser measurement techniques.
基金supported by a joint UK-China research program funded by the Engineering and Physical Sciences Research Council of the UK and the international collaboration funding from Guizhou Science and Technology Department(No.Qian-Ke-He-Wai G[2009]700110)
文摘Waste biomass is always generated during the production process in industries. The ordinary way to get rid of the waste biomass is to send them to landfill or burn it in the open field. The waste may potentially be used for co-firing with coal to save fossil fuel consumption and also reduce net carbon emissions. In this case study, the bio-waste from a Nicotiana Tahacum (NT) pre-treatment plant is used as the biomass to co-fire with coal. The samples of NT wastes were analysed. It was found that the wastes were of the relatively high energy content which were suitable for co-firing with coal. To investigate the potential and benefits for adding NT wastes to a Fluidised Bed Combustion (FBC) boiler in the plant, detailed modelling and simulation are carried out using the European Coal Liquefaction Process Simulation and Evaluation (ECLIPSE) process simulation package. The feedstock blending ratios of NT waste to coal studied in this work are varied from 0% to 30%. The results show that the addition of NT wastes may decrease the emissions of CO2 and SOx without reducing the boiler performance.
文摘It is possible for cost professionals to prepare an informed and compendious cost plan by identifying all the factors that cause cost overruns,variations,safety hazards and others without having a significant prior experience.The implementation of Extended Reality can address this phenomenon.The paper aims to introduce the concept of Extended Reality in the field of quantity surveying by exploring its untapped potential and also looks to identify critical barriers in implementing this technology.A detailed review of literature study produced eight critical factors acting as barriers in successful implementation.With the suggestions from the industry professionals,the inter-relationship among these factors were established and prioritised using Interpretative Structural Modelling(ISM)tool.Further,these factors were categorised using MICMAC(Cross-Impact Matrix Multiplication Applied to Classification)analysis.This study identifies,lack of expertise and lack of suitable software as the key driving factors in successful implementation and all the remaining factors are directly or indirectly influenced by them.The sample size considered in building the ISM network is limited to the Indian construction industry.The disadvantages of Extended Reality have not been covered in the study.There may be several negative repercussions to human health due to this technology.This study can be used by industry professionals in understanding how advance technology like this can overcome many challenges pertinent to cost planning and estimation.This study stands out among the few research topics which contribute to reducing the knowledge gap among the cost professionals irrespective of their experience.
文摘For the past 50 years,the Sydney Opera House has been the subject of a prodigious hagiography of the personalities involved in its realization and their legendary querelles.Yet it remains paradoxically unexplored when it comes to its operative construction decisions,particularly those that relate to the erection of its renowned superstructure.Through the analysis of a newly discovered set of shop drawings prepared for the innovative formwork system of the iconic roof sails,the paper contributes to the construction history of the building whilst shedding light on the hitherto unacknowledged role of the general contractor in the design process.In doing so,it questions the validity of conventional assumptions about the technical division of labour in complex projects,where construction and project management tend to be kept separate from architectural and structural design,furthermore suggesting the need for broader design exegeses,combining project-based and production-based concerns.In reflecting on its import for contemporary practice,the study suggests that the revealing picture of the Sydney Opera House project,as it emerged from the cumbersome archive-based crossanalysis of the manual documentation produced for it,is in principle much easier and perhaps important to obtain today.This is due,on the one side,to availability and diffusion of digital project collaborative platforms;on the other side,to the merging and the blurring of professional and non-professional design contributions.