The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Moon C Won - One of the best experts on this subject based on the ideXlab platform.

  • mesoscale analysis of continuously reinforced concrete pavement behavior subjected to Environmental Loading
    Construction and Building Materials, 2016
    Co-Authors: Seongcheol Choi, Moon C Won
    Abstract:

    Abstract Continuously reinforced concrete pavement (CRCP) behavior due to temperature and moisture variations was analyzed using a mesoscale model consisting of coarse aggregate, mortar, and an interface transition zone (ITZ). The effects of the modulus of elasticity and thermal coefficient of the coarse aggregate and the strength at ITZ were evaluated. The results indicated that the coarse aggregate modulus and the drying shrinkage of the concrete had the most significant effect on the development of nonstructural distresses. Using a coarse aggregate with a lower modulus and reducing the drying shrinkage of concrete are thus expected to improve CRCP performance.

  • behavior of tied multiple lane portland cement concrete pavement effects of Environmental Loading and dowel bar use
    Transportation Research Record, 2010
    Co-Authors: Seongcheol Choi, Moon C Won
    Abstract:

    Tie bars are used at longitudinal construction joints (LCJs) in portland cement concrete (PCC) pavement primarily to keep lanes from separating. As more lanes are tied together because of ever-increasing traffic volume, concerns about the potential for longitudinal cracking have led to the use of dowel bars at LCJs. However, a survey of a number of state highway agencies (SHAs) revealed that few of them have guidelines and design standards for the use of dowel bars at LCJs and that no in-depth studies conducted in this area have been identified. The effects of multiple lane ties and dowel bar placements in PCC pavements are analyzed in this paper to provide basic information on whether dowel bars are really needed, and if they are, where they should be placed and what their advantages and disadvantages are. Field testing verified that the longitudinal cracking potential is greater as slab thickness and lane width increase. The effects of multiple lane ties and dowel bar placements at LCJs are evaluated wi...

  • Time-Dependent Behavior of Posttensioned Concrete Pavements Under Environmental Loading
    Transportation Research Record, 2010
    Co-Authors: Seongcheol Choi, Moon C Won
    Abstract:

    The performance of cast-in-place posttensioned concrete pavement (PTCP) constructed in 1985 on I-35 in Waco, Texas, has been excellent. Encouraged by the performance of the section, the Texas Department of Transportation began construction of another PTCP project in 2008 on I-35 in Hillsboro. In this study, the time-dependent behavior of PTCP under Environmental Loading was experimentally investigated and its implications in PTCP design investigated. Concrete strain and slab movement as well as temperature and relative humidity were measured. The effects of such factors as posttensioning (PT) force, friction, curling stress, creep, and shrinkage on the behavior of PTCP were investigated. The stress introduced by longitudinal PT varied along the slab length, with a maximum near the armor joint and a minimum at the center of the slab. The variations were induced by the friction between concrete and subbase. The concrete strain at middepth of the slab under Environmental Loading was also affected by friction...

  • measurement and analysis of early age concrete strains and stresses continuously reinforced concrete pavement under Environmental Loading
    Transportation Research Record, 2006
    Co-Authors: Jeonghee Nam, Seongmin Kim, Moon C Won
    Abstract:

    The early-age behavior of continuously reinforced concrete pavement (CRCP) in terms of concrete strains and stresses due to Environmental Loading was extensively investigated. The strains measured with strain gauges in the actual CRCP cannot be used simply to calculate the concrete stresses by multiplying the elastic modulus of concrete because the measured strains include both the stress-dependent and -independent strains. In situ stress-independent strains were measured with vibrating wire gauges embedded in the modified half-cylinders developed in this study and in small beams. The total strains in the concrete were measured with vibrating wire gauges at different depths in both the longitudinal and transverse directions at the crack-induced area and the surrounding areas in several test sections. The crack width variation through the depth of the pavement was also measured with the gauges installed at the crack-induced area. The in situ coefficient of thermal expansion and drying shrinkage of concrete...

Sergio Ulgiati - One of the best experts on this subject based on the ideXlab platform.

  • Indicators of Environmental Loading and sustainability of urban systems. An emergy-based Environmental footprint
    Ecological Indicators, 2017
    Co-Authors: Silvio Viglia, Dario Felice Civitillo, Gianluca Cacciapuoti, Sergio Ulgiati
    Abstract:

    Abstract Cities are the engine of economic development and human wellbeing, but their dynamics needs to be supported by the convergence of large flows of material and energy resources. Assessing a city resource metabolism becomes increasingly crucial, not only concerning the relation with the environment as a source or a sink, but also concerning the internal dynamics of resource exchange among city components and sectors. We applied Emergy Accounting (EMA) and Cumulative Energy Demand (CED) methods to develop and validate indicators of urban Environmental sustainability, using as case studies five urban systems of different size in Italy. CED allowed an assessment of the commercial energy consumption required on local and global scales to support the city life and economy. Airborne emissions related to direct and indirect energy consumption were also assessed. EMA was used to quantify the Environmental support required for the urban metabolism, in terms of resource generation and ecosystem services supply. Combining these three aspects, a new metric is discussed and developed to estimate the Environmental impact of cities, with reference to their resource use, in order to implement comprehensive indicators and suggest resource use criteria at urban level. A city’s support area to buffer upstream and downstream Environmental Loading is also calculated. Relative and absolute sustainability concepts are introduced and discussed, showing how far the investigated cities are from a resource-based Environmentally sustainable state. Finally, practices are suggested as an exit strategy from the present intensive fossil powered economy towards a higher level of Environmental sustainability and wellbeing.

  • ecological impacts of small hydropower in china insights from an emergy analysis of a case plant
    Energy Policy, 2015
    Co-Authors: Mingyue Pang, Sergio Ulgiati, Lixiao Zhang, Changbo Wang
    Abstract:

    Abstract The belief that small hydropower (SHP) systems are sources of clean energy with few or no ecological problems has been driving the rapid expansion of SHP plants in China and elsewhere. This paper presents an evaluation of the ecological impacts of SHP based on an emergy analysis of a plant located in Guizhou Province in southwest China. The results suggest that periodic downstream drying-up of the river is the largest contributor to the induced ecological impacts in terms of emergy cost. In 2010, the ecosystem service losses caused by downstream ecosystem degradation totaled 2.35E+18 seJ, which accounts for 38% of the total emergy utilized in the annual operation of this plant. If such losses could be avoided, i.e., if the SHP operated as designed, SHP projects would produce relatively modest impacts on the environment. When the reaches downstream of the SHP plant are not affected, the Environmental Loading ratio (ELR) is 2.20 and the emergy sustainability index (ESI) is 0.93; however, the ELR increases to 3.82 and ESI decreases to 0.38 when river drying-up occurs. These results indicate that China should rigorously investigate potential ecological problems of SHP development and proceed with caution rather than readily believing unjustified assumptions.

  • emergy evaluations and Environmental Loading of electricity production systems
    Journal of Cleaner Production, 2002
    Co-Authors: Mark T Brown, Sergio Ulgiati
    Abstract:

    Abstract Six electricity production systems are evaluated using energy and emergy (Environmental Accounting. Emergy and Environmental Decision Making. New York:Wiley, 1996. 370pp.) accounting techniques, in order to rank their relative thermodynamic and Environmental efficiencies. The output/input energy ratio as well as the emergy-based emergy yield ratio (EYR) and Environmental Loading ratio (ELR) have been jointly used to explore and compare system performances. Generation of CO2 has also been accounted for in order to compare renewable and nonrenewable energy sources. The production systems include both plants using nonrenewable energy sources (natural gas, oil, and coal thermal plants) and the so-called renewable energy sources (geothermal, hydroelectric, and wind plants). A method for evaluating the Environmental contribution to electric production is shown to provide important information that can be used to support the Environmentally sound public policy. Renewable power plants were characterized by high energy return on investment, while fossil fueled plants exhibited average energy efficiency in the 25–36% range. EYR varied from a high of 7.6/1 for hydroelectric generation to about 4.2/1 for the oil thermal plant. The renewable energy plants required the highest Environmental inputs per unit of output while fossil fuel plants required relatively small Environmental inputs for cooling and to support fuel combustion. Environmental Loading was highest with thermal plants. Using an emergy index of sustainability, it is quantitatively shown how renewable energy source plants like wind, hydroelectric, and geothermal had higher sustainability compared to thermal plants.

  • emergy evaluation of the biosphere and natural capital
    AMBIO: A Journal of the Human Environment, 1999
    Co-Authors: Mark T Brown, Sergio Ulgiati
    Abstract:

    The measure of value called emergy is used to evaluate the flows of energy and resources that sustain the biosphere including the economy of humans. A donor system of value based on solar emergy required to produce things is suggested as the only means of reversing the logic trap inherent in economic valuation, which suggests that value stems only from utilization by humans. The stocks of natural capital and flows of Environmental resources are evaluated in emergy and related to Global World Product. Several emergy indices are introduced as a means of evaluating sustainability of economies and processes. The total emergy flux of the biosphere is composed of 32% renewable flows of sunlight, tidal momentum and deep heat (it was 68% in 1950), and 68% slowly-renewable and nonrenewable flows. An index of Environmental Loading on the biosphere is shown to have increased about 4 times since 1950, while an index of global sustainability suggests that overall, sustainability of the global economy has precipitously declined.

  • emergy use Environmental Loading and sustainability an emergy analysis of italy
    Ecological Modelling, 1994
    Co-Authors: Sergio Ulgiati, Howard T Odum, Simone Bastianoni
    Abstract:

    Abstract Maximizing emergy flow is the new statement (Odum, 1988a, 1991) of Lotka's maximum power principle (1992a, b): self-organizing systems which maximize emergy flow and reinforce production are sustainable, the others are displaced by those with better reinforcement of their productive basis. An emergy analysis of the Italian system of economy and nature was performed in order to study its sustainability and emergy use. Indices of thermodynamic and economic vitality of Italy were evaluated and a comparison with indices of other developed and developing countries was performed.

E. R. Atwill - One of the best experts on this subject based on the ideXlab platform.

  • farm factors associated with reducing cryptosporidium Loading in storm runoff from dairies
    Journal of Environmental Quality, 2008
    Co-Authors: Woutrina A Miller, Kenneth W Tate, David J Lewis, M D G Pereira, Michael Lennox, Patricia A Conrad, E. R. Atwill
    Abstract:

    A systems approach was used to evaluate Environmental Loading of Cryptosporidium oocysts on five coastal dairies in California. One aspect of the study was to determine Cryptosporidium oocyst concentrations and loads for 350 storm runoff samples from dairy high use areas collected over two storm seasons. Selected farm factors and beneficial management practices (BMPs) associated with reducing the Cryptosporidium load in storm runoff were assessed. Using immunomagnetic separation (IMS) with direct fluorescent antibody (DFA) analysis, Cryptosporidium oocysts were detected on four of the five farms and in 21% of storm runoff samples overall. Oocysts were detected in 59% of runoff samples collected near cattle less than 2 mo old, while 10% of runoff samples collected near cattle over 6 mo old were positive. Factors associated with Environmental Loading of Cryptosporidium oocysts included cattle age class, 24 h precipitation, and cumulative seasonal precipitation, but not percent slope, lot acreage, cattle stocking number, or cattle density. Vegetated buffer strips and straw mulch application significantly reduced the protozoal concentrations and loads in storm runoff, while cattle exclusion and removal of manure did not. The study findings suggest that BMPs such as vegetated buffer strips and straw mulch application, especially when placed near calf areas, will reduce Environmental Loading of fecal protozoa and improve stormwater quality. These findings are assisting working dairies in their efforts to improve farm and ecosystem health along the California coast.

  • climate and on farm risk factors associated with giardia duodenalis cysts in storm runoff from california coastal dairies
    Applied and Environmental Microbiology, 2007
    Co-Authors: Woutrina A Miller, Kenneth W Tate, David J Lewis, M D G Pereira, Michael Lennox, Patricia A Conrad, E. R. Atwill
    Abstract:

    Climatic factors and on-farm management practices were evaluated for their association with the concentrations (cyst/liter) and instantaneous loads (cysts/second) of Giardia duodenalis in storm-based runoff from dairy lots and other high-cattle-use areas on five coastal California farms over two storm seasons. Direct fluorescent antibody analysis was used to quantitate cysts in 350 storm runoff samples. G. duodenalis was detected on all five dairy farms, with fluxes of 1 to 14,000 cysts/liter observed in 16% of samples. Cysts were detected in 41% of runoff samples collected near cattle less than 2 months old, compared to 10% of runoff samples collected near cattle over 6 months old. Furthermore, the concentrations and instantaneous loads of cysts were >65 and >79 times greater, respectively, in runoff from sites housing young calves than in sites housing other age classes of animals. Factors associated with Environmental Loading of G. duodenalis included cattle age, cattle stocking number, and precipitation but not lot area, land slope, or cattle density. Vegetated buffer strips were found to significantly reduce waterborne cysts in storm runoff: each additional meter of vegetated buffer placed below high-cattle-use areas was associated with reductions in the concentration and instantaneous load of cysts by factors of 0.86 and 0.79 (0.07 and 0.10 log10/m), respectively. Straw mulch, seed application, scraping of manure, and cattle exclusion did not significantly affect the concentration or load of G. duodenalis cysts. The study findings suggest that vegetated buffer strips, especially when placed near dairy calf areas, should help reduce the Environmental Loading of these fecal protozoa discharging from dairy farms.

  • improved quantitative estimates of low Environmental Loading and sporadic periparturient shedding of cryptosporidium parvum in adult beef cattle
    Applied and Environmental Microbiology, 2003
    Co-Authors: E. R. Atwill, B. R. Hoar, Das Gracas Cabral M Pereira, Kenneth W Tate, Franz Rulofson, Glenn Nader
    Abstract:

    concentrations as low as 3.2 oocysts g of feces 1 , with a 54% probability of detecting just one oocyst g of feces 1 . Using this diagnostic method, the overall apparent prevalence of adult beef cattle testing positive for C. parvum was 7.1% (17 of 240), with 8.3 and 5.8% of cattle shedding oocysts during the pre- and postcalving periods, respectively. The mean intensity of oocyst shedding for test-positive cattle was 3.38 oocysts g of feces 1 . The estimated Environmental Loading rate of C. parvum ranged from 3,900 to 9,200 oocysts cow 1 day 1 , which is substantially less than a previous estimate of 1.7 10 5 oocysts cow 1 day 1 (range of 7.7 10 4 to 2.3 10 5 oocysts cow 1 day 1 ) (B. Hoar, E. R. Atwill, and T. B. Farver, Quant. Microbiol. 2:21-36, 2000). Use of this

  • Estimating Maximum Possible Environmental Loading Amounts of Cryptosporidium parvum Attributable to Adult Beef Cattle
    Quantitative Microbiology, 2000
    Co-Authors: B. R. Hoar, E. R. Atwill, T. B. Farver, T. Jones
    Abstract:

    Populations of beef cattle represent a potential non-point source of Environmental contamination for Cryptosporidium parvum if on-farm management practices fail to minimize transport from bovine manure to adjacent water sources. Characterizing this risk of contamination requires several parameters to be estimated, the most important being a valid and precise estimate of the oocyst Loading rate per animal unit. The oocyst Loading rate is defined in this study as the total number of oocysts excreted by a cohort of adult beef cows during a 24[emsp4 ]h period. We propose a methodology for estimating this parameter for low prevalent populations whereby the majority of individuals are test negative. Under specific degrees of confidence and at the population scale, this methodology generates estimates for maximal oocyst Loading based on the sensitivity of the diagnostic test and the point prevalence and intensity of fecal shedding from a cross-sectional survey of the target population. Our cross-sectional survey on California beef cows generated a prevalence of infection of 1.1 % (6/557) and an intensity of oocyst shedding ranging from 219 to 5,491 oocysts/g, with a geometric mean of 835 oocysts/g from six positive cows. Negative binomial estimate of the percent recovery of the diagnostic assay was 0.235. Based on this percent recovery and using approximately 19.4[emsp4 ]mg of feces per assay, the DT_90 of our assay, defined as the concentration of oocysts at which our diagnostic assay had a 90 % probability of detecting one or more oocysts in a sample, was 755 oocyst/g feces. At a 95 % confidence level, the estimated maximum number of oocysts being excreted in the feces of California beef cows ranged from 4.8 to 14.4 oocysts/g feces/cow, or 7.7×10^4 to 2.3×10^5 oocysts/beef cow/day.

Changbo Wang - One of the best experts on this subject based on the ideXlab platform.

  • ecological impacts of small hydropower in china insights from an emergy analysis of a case plant
    Energy Policy, 2015
    Co-Authors: Mingyue Pang, Sergio Ulgiati, Lixiao Zhang, Changbo Wang
    Abstract:

    Abstract The belief that small hydropower (SHP) systems are sources of clean energy with few or no ecological problems has been driving the rapid expansion of SHP plants in China and elsewhere. This paper presents an evaluation of the ecological impacts of SHP based on an emergy analysis of a plant located in Guizhou Province in southwest China. The results suggest that periodic downstream drying-up of the river is the largest contributor to the induced ecological impacts in terms of emergy cost. In 2010, the ecosystem service losses caused by downstream ecosystem degradation totaled 2.35E+18 seJ, which accounts for 38% of the total emergy utilized in the annual operation of this plant. If such losses could be avoided, i.e., if the SHP operated as designed, SHP projects would produce relatively modest impacts on the environment. When the reaches downstream of the SHP plant are not affected, the Environmental Loading ratio (ELR) is 2.20 and the emergy sustainability index (ESI) is 0.93; however, the ELR increases to 3.82 and ESI decreases to 0.38 when river drying-up occurs. These results indicate that China should rigorously investigate potential ecological problems of SHP development and proceed with caution rather than readily believing unjustified assumptions.

  • Emergy analysis of a small hydropower plant in southwestern China
    Ecological Indicators, 2014
    Co-Authors: Lixiao Zhang, Mingyue Pang, Changbo Wang
    Abstract:

    Abstract Although its Environmental performance and sustainability remain unclear, small hydropower (SHP) has undergone rapid expansion in China. Through emergy analysis, this study aimed to assess the Environmental impact and relative sustainability of a small hydroelectric plant in Guizhou Province, which is located in southwestern China, in 2010. The analysis included a comparison with similar evaluations that were conducted for large hydroelectric projects: two hydropower dams on the Mekong River in Thailand, one multipurpose dam in Korea, and the Three Gorges Dam in China. As indicated by the emergy yield ratio (EYR), Environmental Loading ratio (ELR), and emergy sustainability index (ESI), the overall Environmental performance of the SHP system examined in this research surpassed the Environmental performance of large dams. However, Environmentally sensible designs do not automatically imply a promising future. The case-study SHP is on the verge of bankruptcy due to financial losses, which can be attributed to the current grid-connected cost of electricity of 0.23 CNY/kWh. The emergy exchange ratio (EER) quantitatively demonstrates that the fair price of electricity from the perspective of emergy balance is 0.4 CNY/kWh. The sensitivity analysis reveals that the inherent defect of unstable operation, which is exhibited by the SHP system, greatly affects the Environmental performance of a SHP plant.

Weiping Jiang - One of the best experts on this subject based on the ideXlab platform.

  • influences of Environmental Loading corrections on the nonlinear variations and velocity uncertainties for the reprocessed global positioning system height time series of the crustal movement observation network of china
    Remote Sensing, 2018
    Co-Authors: Peng Yuan, Weiping Jiang, Wu Chen, Nico Sneeuw
    Abstract:

    Mass redistribution of the atmosphere, oceans, and terrestrial water storage generates crustal displacements which can be predicted by Environmental Loading models and observed by the Global Positioning System (GPS). In this paper, daily height time series of 235 GPS stations derived from a homogeneously reprocessed Crustal Movement Observation Network of China (CMONOC) and corresponding Loading displacements predicted by the Deutsche GeoForschungsZentrum (GFZ) are compared to assess the effects of Loading corrections on the nonlinear variations of GPS time series. Results show that the average root mean square (RMS) of vertical displacements due to atmospheric, nontidal oceanic, hydrological, and their combined effects are 3.2, 0.6, 2.7, and 4.0 mm, respectively. Vertical annual signals of Loading and GPS are consistent in amplitude but different in phase systematically. The average correlation coefficient between Loading and GPS height time series is 0.6. RMS of the GPS height time series are reduced by 20% on average. Moreover, an investigation of 208 CMONOC stations with observing time spans of ~4.6 years shows that Environmental Loading corrections lead to an overestimation of the GPS velocity uncertainty by about 1.4 times on average. Nevertheless, by using a common mode component filter through principal component analysis, the dilution of velocity precision due to Environmental Loading corrections can be compensated.

  • noise analysis for Environmental Loading effect on gps time series
    Acta Geodynamica et Geomaterialia, 2016
    Co-Authors: Jeanphilippe Montillet, Xianghong Hua, Weiping Jiang, Feng Zhou
    Abstract:

    This paper focusses on the impact of environment mass Loading on GPS time-series of position changes and noise characteristic. We make use of position time series of 206 GPS station ranging from 2001 to 2013 globally distributed. Firstly, we investigate the spatio-temporal pattern of mass Loadings based on QLM dataset. The results show that Loading effect is significant for short time series, and the instantaneous impact cannot be ignored especially in high-precision geophysical studies. Meanwhile, the results indicate that Loading effect behaves with regional difference in spatial scale, and this explains why there exist significant differences on the contribution of Environmental Loading on GPS time series in the scientific community. Secondly, among 90 % of the stations the weighted root mean square (WRMS) is reduced after applying the Loading correction based on QLM model, improving the accuracy of GPS time series. Finally, we quantify the stochastic of GPS time series. The results show that the noise model of GPS time series can be described by a various combination of those models, mainly by FN+WN model and PL+WN model. From our statistics, we can conclude that the best noise models are either white and flicker or white and power-law. Environment Loading has a significant impact on the stochastic noise properties of GPS time series, on 33 %, 15 %, and 39 % of the station's noise properties (noise types) have been changed after Loading correction for NEU components, respectively. Environment Loading is one of the factor that 'raw' GPS time series exhibited Gauss Markov noise properties. Furthermore, the impact of Environmental Loading on GPS site velocity cannot be ignored; this is particularly significant for the vertical component.

  • comparative analysis of different Environmental Loading methods and their impacts on the gps height time series
    Journal of Geodesy, 2013
    Co-Authors: Weiping Jiang, Tonie Van Dam, Wenwu Ding
    Abstract:

    Three different Environmental Loading methods are used to estimate surface displacements and correct non-linear variations in a set of GPS weekly height time series. Loading data are provided by (1) Global Geophysical Fluid Center (GGFC), (2) Loading Model of Quasi-Observation Combination Analysis software (QLM) and (3) our own daily Loading time series (we call it OMD for optimum model data). We find that OMD has the smallest scatter in height across the selected 233 globally distributed GPS reference stations, GGFC has the next smallest variability, and QLM has the largest scatter. By removing the load-induced height changes from the GPS height time series, we are able to reduce the scatter on 74, 64 and 41 % of the stations using the OMD models, the GGFC model and QLM model respectively. We demonstrate that the discrepancy between the center of earth (CE) and the center of figure (CF) reference frames can be ignored. The most important differences between the predicted models are caused by (1) differences in the hydrology data from the National Center for Atmospheric Research (NCEP) vs. those from the Global Land Data Assimilation System (GLDAS), (2) grid interpolation, and (3) whether the topographic effect is removed or not. Both QLM and GGFC are extremely convenient tools for non-specialists to use to calculate Loading effects. Due to the limitation of NCEP reanalysis hydrology data compared with the GLDAS model, the GGFC dataset is much more suitable than QLM for applying Environmental Loading corrections to GPS height time series. However, Loading results for Greenland from GGFC should be discarded since hydrology data from GLDAS in this region are not accurate. The QLM model is equivalent to OMD in Greenland and, hence, could be used as a complement to the GGFC product to model the load in this region. We find that the predicted Loading from all three models cannot reduce the scatter of the height coordinate for some stations in Europe.