Conservation of marmots, large ground-dwelling squirrels restricted to the northern hemisphere, was impacted by direct human activity through hunting or modifying ecosystem dynamics. Regulating human activities reduce...Conservation of marmots, large ground-dwelling squirrels restricted to the northern hemisphere, was impacted by direct human activity through hunting or modifying ecosystem dynamics. Regulating human activities reduced the threat of extinction. Climate change, an indirect human impact, threatens marmot survival through global warming and extreme weather events. Most marmot species occupy a harsh environment characterized by a short growing season and a long, cold season without food. Marmots cope with seasonality by hibernating. Their large size increases the efficiency of fat accumulation and its use as the sole energy source during hibernation. Marmot physiology is highly adapted to coping with low environmental temperatures;they are stressed by high heat loads. Global warming since the last ice age reduced the geographic distribution of some of the 15 species of marmots. Recent warming resulted in a movement upslope of their lower elevation boundary. This process likely will continue because warming is associated with drier unpalatable vegetation. Drought reduces reproduction and increases mortality;thus decreased summer rainfall in the montane environments where marmots live may cause local extinction. Snow cover, a major environmental factor, is essential to insulate hibernation burrows from low, stressful temperatures. However, prolonged vernal snow cover reduces reproduction and increases mortality. Montane areas currently lacking marmot populations because vernal snow cover persists beyond the time that marmots must begin foraging may become colonized if warming causes earlier snow melt. This benefit will be short-lived because decreased precipitation likely will result in unpalatable vegetation. Although some marmot populations are physiologically adapted to a warmer climate, global warming will increase too rapidly for any significant evolutionary response to dryness. The species that live in high, alpine meadows where tree and shrub invasions occur are most threatened with extinction. Captive breeding can preserve marmot species in the shortrun, but is impractical over the long-term. Widespread species are unlikely to be endangered in the foreseeable future, but local, low elevation populations will be lost.展开更多
This study examines how accurate young adults in the Iraqi Kurdistan Region, as an emerging democracy in the Middle East, express their core values through social media (Facebook in this context). It also explores w...This study examines how accurate young adults in the Iraqi Kurdistan Region, as an emerging democracy in the Middle East, express their core values through social media (Facebook in this context). It also explores whether privacy affects with value disclosure. Findings show that value disclosure and definition of privacy varied greatly among respondents and from one value to another. Based on in-depth interview with 12 young adults, the study finds that religious, social, and cultural values have been easily and freely expressed on Facebook accounts by the majority of young adults, whereas other values such as honesty, freedom of speech, and political beliefs are being held by others mainly for privacy issues and political reasons. Democracy was a core value for some young adults seeking to make sense of the western principles of democracy and that reflect on their Facebook account. Results suggest that male respondents practice more freedom and less caution about their privacy than the female respondents on Facebook.展开更多
After successfully locating one abandoned brine well by an electromagnetic method during testing in 2001 and five abandoned brine wells by a high resolution magnetic method during 2002, a high resolution magnetic meth...After successfully locating one abandoned brine well by an electromagnetic method during testing in 2001 and five abandoned brine wells by a high resolution magnetic method during 2002, a high resolution magnetic method was again proposed to search for wells in 2003 when a second sensor was employed to acquire data for calculating the pseudo vertical gradient of magnetic fields. Total area surveyed in 2003 was 1,024,000 ft 2, which was divided into grids with an average size of 10,000 ft 2 and distributed across eight different sites. Magnetic anomalies and their vertical gradients from known brine wells were first recorded as signatures to identify anomalies caused by possible buried brine wells. Of fifty one verified anomalies, thirty one anomalies were due to wells buried at depths from 0 to 8.5 ft: twenty one 6 to 9 inch abandoned brine wells, seven 1.5 to 3 inch probable water wells, one 16 inch dewatering well for a construction site at a depth of 3 ft, and two 4 inch wells on the ground surface. Approximate monopole shaped anomalies were observed from all these wells after data corrections. However, the range of amplitudes of magnetic anomalies from 7,000 to 28,000 nT from these abandoned brine wells was measured. This range of anomalies is mainly due to the thickness and depth of buried wells. Anomaly amplitudes from 1.5 to 3 inch wells are 4,000 to 8,000 nT and linearly correlate with the buried depth. One 3 inch well that caused an anomaly of 13,000 nT could be the inner pipe of a brine well. Gradient anomalies are roughly in a range of 100 to 200 nT/inch for 1.5 to 3 inch wells and 200 to 300 nT/inch for brine wells.As indicated by the potential field theory, gradient data possess higher horizontal resolution than the magnetic field itself. Gradient data provide valuable assistance in determining horizontal locations of anomaly sources for excavation. In practice, however, improvement in the horizontal resolution is limited by survey line spacing. If only one sensor is used in a survey, there is rapid decrease in the horizontal resolution when sensor height increases from 14 to 44 inches. This indicates that it is critical to keep the sensor as close to the ground as possible when hunting buried wells that are close to each other. It also suggests that the downward continuation is useful to increase the horizontal resolution in well hunting.展开更多
Ammopiptanthus nanus is an endangered evergreen shrub endemic to the deserts of central Asia and plays an important role in delaying further desertification. We examined allozyme variation and AFLP diversity in A. nan...Ammopiptanthus nanus is an endangered evergreen shrub endemic to the deserts of central Asia and plays an important role in delaying further desertification. We examined allozyme variation and AFLP diversity in A. nanus populations and investigated the mating system of this species using progeny arrays assayed for polymorphic allozyme loci. Mating system analysis in the Keyi'eryongke'er population showed low levels of outcrossing, and strong inbreeding depression. Low levels of genetic variation were detected at both population (allozyme, Pp=14.0%, A=l.14, He=0.031; AFLP, Pp=14.5%, Shannon's information index I=0.063) and species (allozyme, Pp=21.1%, A=1.21, He=0.040; AFLP, Pp=20.9%, I=0.083) levels; while moderate genetic differentiation existed among populations, as indicated by allozymes (Gsa-=0.081) and AFLP (GST=0.151-0.193). Founder effect, bottlenecks in evolutionary history, the mixed mating system and co-ancestry may have influenced the level of genetic diversity in A. nanus. Markers of both types provide new insights for conservation management, indicating that the Biao'ertuokuoyi and Keyi'eryongke'er populations should be given priority for in situ conservation and regarded as seed sources for ex situ conservation.展开更多
In-situ gelation of aqueous sulfomethylated resorcinol formaldehyde (SMRF) system inBerea core has been investigated. Two sets of displacement experiments were conducted with thissystem (containing 5% NaCl, 0. 036% Ca...In-situ gelation of aqueous sulfomethylated resorcinol formaldehyde (SMRF) system inBerea core has been investigated. Two sets of displacement experiments were conducted with thissystem (containing 5% NaCl, 0. 036% CaCl_2. 2H_2O). The brine permeabilities of the coreswere reduced significantly from about 600 to 0.1 md. The in-situ gelation in Berea core occurreda little bit earlier than gelation anticipated from bulk test in the experiments. The gel time waseasier to control at initial pH between 6 and 8. During injection of SMRF system, the apparentviscosity was less than 1 mPa·s at 41℃.展开更多
Factors affecting the gelation of resorcinol-formaldehyde systems have been examined overvariable ranges applicable to oilfield use. Gelation of resorcinol-formaldehyde (RF) system wassensitive to pH,salinity and hard...Factors affecting the gelation of resorcinol-formaldehyde systems have been examined overvariable ranges applicable to oilfield use. Gelation of resorcinol-formaldehyde (RF) system wassensitive to pH,salinity and hardness. Generally,this gel system could be used in fresh water orlow salinity brine at pH higher than about 9. The application would require careful monitoring ofinjection fluids to avoid premature gelation or prolonged shut-in times,especially under conditionsof low salinity and high pH. Salinity and hardness compatibilities of the system were improved bysulfomethylation of resorcinol. Aqueous sulfomethylated resorcinol formaldehyde (SMRF)system could be used in brine with higher salinity and hardness and at a wider pH range of 5--10.展开更多
This paper considers conservation and balance laws and the constitutive theories for non-classical viscous fluent continua without memory, in which internal rotation rates due to the velocity gradient tensor are incor...This paper considers conservation and balance laws and the constitutive theories for non-classical viscous fluent continua without memory, in which internal rotation rates due to the velocity gradient tensor are incorporated in the thermodynamic framework. The constitutive theories for the deviatoric part of the symmetric Cauchy stress tensor and the Cauchy moment tensor are derived based on integrity. The constitutive theories for the Cauchy moment tensor are considered when the balance of moments of moments 1) is not a balance law and 2) is a balance law. The constitutive theory for heat vector based on integrity is also considered. Restrictions on the material coefficients in the constitutive theories for the stress tensor, moment tensor, and heat vector are established using the conditions resulting from the entropy inequality, keeping in mind that the constitutive theories derived here based on integrity are in fact nonlinear constitutive theories. It is shown that in the case of the simplest linear constitutive theory for stress tensor used predominantly for compressible viscous fluids, Stokes' hypothesis or Stokes'?assumption has no thermodynamic basis, hence may be viewed incorrect. Thermodynamically consistent derivations of the restrictions on various material coefficients are presented for non-classical as well as classical theories that are applicable to nonlinear constitutive theories, which are inevitable if the constitutive theories are derived based on integrity.展开更多
Evaluation of the conspicuity of roadway environments for their environmental impact on driving performance is vital for roadway safety. Existing meters and tools for roadway measurements cannot record light and geome...Evaluation of the conspicuity of roadway environments for their environmental impact on driving performance is vital for roadway safety. Existing meters and tools for roadway measurements cannot record light and geometry data simultaneously in a high resolution. This study introduced a new method that adopted recently developed high dynamic range (HDR) photogrammetry to measure the luminance and XYZ coordinates of millions of points across a road scene with the same device—a camera, and a MatLab code for data treatment and visualization. To validate this method, the roadway environments of a straight and flat section of Jayhawk Boulevard (482.8 m long) at Lawrence, KS and a roundabout (15.3 m in diameter) at its end were measured under clear and cloudy sky in the daytime and at nighttime with dry and wet pavements. Eight HDR images of the roadway environments under different viewing conditions were generated using the HDR photogrammetric techniques and calibrated. From each HDR image, synchronous light and geometry data were extracted in Radiance and further analyzed to identify potential roadway environmental hazards using the MatLab code (http://people.ku.edu/~h717c996/research.html). The HDR photogrammetric measurement with current equipment had a margin of errors for geometry measurement that varied with the measuring distance, averagely 23.1% - 27.5% for the Jayhawk Boulevard and 9.3% - 16.2% for the roundabout. The accuracy of luminance measurement was proven in the literature as averagely 1.5% - 10.1%. The camera-aided measurement is fast, non-contact, non-destructive, and off the road, thus, it is deemed more efficient and safer than conventional ways using meters and tools. The HDR photogrammetric techniques with current equipment still need improvements on accuracy and speed of the data treatment.展开更多
This project was intended to determine whether the preprogrammed time-varying recharge protocol for a battery incased in a neuromodulation implant can give rise to tissue temperatures that surpass a safe level or are ...This project was intended to determine whether the preprogrammed time-varying recharge protocol for a battery incased in a neuromodulation implant can give rise to tissue temperatures that surpass a safe level or are otherwise benign. The study included the development of a highly accurate model of all the thermal processes that are activated by the recharging of the battery contained within the neuromodulation implant. The model was implemented by numerical simulations performed for several realistic operating conditions. The computed spatial and temporal tissue temperature distributions were employed to estimate possible tissue damage by making use of two independent methodologies. Independent calorimeter-based experiments were performed to provide validation for the calculated rates of heat generation in the coils of the implant. Spatial and temporal tissue temperature distributions extracted from the numerical simulations revealed the thermal effects associated with several realistic operating protocols. None of the operating protocols gave rise to temperatures above 42℃. Numerical values of thermal tissue damage metrics were determined and compared with accepted values which correspond to the absence and the presence of tissue damage. The experimentally determined rate of heat generation in the implant coils validated that from electrical measurements to within 2%. Both the tissue temperature results and the thermal damage metrics found no evidence of tissue injury when time-varying preprogrammed protocols are used in the recharging of neuromodulation implant-encased batteries.展开更多
Hurricane-induced hazards can result in significant damage to the built environment cascading into major impacts to the households,social institutions,and local economy.Although quantifying physical impacts of hurrica...Hurricane-induced hazards can result in significant damage to the built environment cascading into major impacts to the households,social institutions,and local economy.Although quantifying physical impacts of hurricane-induced hazards is essential for risk analysis,it is necessary but not sufficient for community resilience planning.While there have been several studies on hurricane risk and recovery assessment at the building-and community-level,few studies have focused on the nexus of coupled physical and social disruptions,particularly when char-acterizing recovery in the face of coastal multi-hazards.Therefore,this study presents an integrated approach to quantify the socio-physical disruption following hurricane-induced multi-hazards(e.g.,wind,storm surge,wave)by considering the physical damage and functionality of the built environment along with the population dynamics over time.Specifically,high-resolution fragility models of buildings,and power and transportation infrastructures capture the combined impacts of hurricane loading on the built environment.Beyond simulat-ing recovery by tracking infrastructure network performance metrics,such as access to essential facilities,this coupled socio-physical approach affords projection of post-hazard population dislocation and temporal evolution of housing and household recovery constrained by the building and infrastructure recovery.The results reveal the relative importance of multi-hazard consideration in the damage and recovery assessment of communities,along with the role of interdependent socio-physical system modeling when evaluating metrics such as housing recovery or the need for emergency shelter.Furthermore,the methodology presented here provides a foundation for resilience-informed decisions for coastal communities.展开更多
Conflicts between supply chain members emerge because individual strategic actions may not be jointly optimal.Efforts to forecast consumer demand represent a source of conflict.The coordination of forecasts requires a...Conflicts between supply chain members emerge because individual strategic actions may not be jointly optimal.Efforts to forecast consumer demand represent a source of conflict.The coordination of forecasts requires a powerful incentive alignment approach.This work proposes a smart contract equipped consortium blockchain system that creates an incentive structure that makes coordination with respect to forecasts economically appealing.Distortions of demand information due to uncoordinated forecasting are captured by a bullwhip measure that factors both forecast error and variance.Cooperation under the system is shown to help minimize this bullwhip measure,thus generating new outcomes for the participants that allow for a higher reward.Under a fixed payout structure,the system achieves credibility of continued cooperation,thus promoting an optimally coordinated equilibrium between the retailer and supplier.Blockchain technology represents a novel information system and consensus formation mechanism that can intermediate the behavior of a supply chain network.展开更多
Fatigue cracks that develop in civil infrastructure such as steel bridges due to repetitive loads pose a major threat to structural integrity.Despite being the most common practice for fatigue crack detection,human vi...Fatigue cracks that develop in civil infrastructure such as steel bridges due to repetitive loads pose a major threat to structural integrity.Despite being the most common practice for fatigue crack detection,human visual inspection is known to be labor intensive,time-consuming,and prone to error.In this study,a computer vision-based fatigue crack detection approach using a short video recorded under live loads by a moving consumer-grade camera is presented.The method detects fatigue crack by tracking surface motion and identifies the differential motion pattern caused by opening and closing of the fatigue crack.However,the global motion introduced by a moving camera in the recorded video is typically far greater than the actual motion associated with fatigue crack opening/closing,leading to false detection results.To overcome the challenge,global motion compensation(GMC)techniques are introduced to compensate for camera-induced movement.In particular,hierarchical model-based motion estimation is adopted for 2D videos with simple geometry and a new method is developed by extending the bundled camera paths approach for 3D videos with complex geometry.The proposed methodology is validated using two laboratory test setups for both in-plane and out-of-plane fatigue cracks.The results confirm the importance of motion compensation for both 2D and 3D videos and demonstrate the effectiveness of the proposed GMC methods as well as the subsequent crack detection algorithm.展开更多
This study examined electromyographic amplitude(EMGRMS)-force relationships during repeated submaximal knee extensor muscle actions among chronic aerobically-(AT),resistance-trained(RT),and sedentary(SED)individuals.F...This study examined electromyographic amplitude(EMGRMS)-force relationships during repeated submaximal knee extensor muscle actions among chronic aerobically-(AT),resistance-trained(RT),and sedentary(SED)individuals.Fifteen adults(5/group)attempted 20 isometric trapezoidal muscle actions at 50%of maximal strength.Surface electromyography(EMG)was recorded from vastus lateralis(VL)during the muscle actions.For the first and last successfully completed contractions,linear regression models were fit to the log-transformed EMGRMS-force relationships during the linearly increasing and decreasing segments,and the b terms(slope)and a terms(antilog of y-intercept)were calculated.EMGRMS was averaged during steady force.Only the AT completed all 20 muscle actions.During the first contraction,the b terms for RT(1.3010.197)were greater than AT(0.9100.123;p?0.008)and SED(0.9120.162;p?0.008)during the linearly increasing segment,and in comparison to the linearly decreasing segment(1.0180.139;p?0.014),respectively.For the last contraction,the b terms for RT were greater than AT during the linearly increasing(RT?1.3730.353;AT?0.8830.129;p?0.018)and decreasing(RT?1.5260.328;AT?0.9700.223;p?0.010)segments.In addition,the b terms for SED increased from the linearly increasing(0.9680.144)to decreasing segment(1.2680.126;p?0.015).There were no training,segment,or contraction differences for the a terms.EMGRMS during steady force increased from the first-([64.0851.68]μV)to last-contraction([86.7349.55]μV;p?0.001)collapsed across training statuses.The b terms differentiated the rate of change for EMGRMS with increments in force among training groups,indicating greater muscle excitation to the motoneuron pool was necessary for the RT than AT during the linearly increasing and decreasing segments of a repetitive task.展开更多
文摘Conservation of marmots, large ground-dwelling squirrels restricted to the northern hemisphere, was impacted by direct human activity through hunting or modifying ecosystem dynamics. Regulating human activities reduced the threat of extinction. Climate change, an indirect human impact, threatens marmot survival through global warming and extreme weather events. Most marmot species occupy a harsh environment characterized by a short growing season and a long, cold season without food. Marmots cope with seasonality by hibernating. Their large size increases the efficiency of fat accumulation and its use as the sole energy source during hibernation. Marmot physiology is highly adapted to coping with low environmental temperatures;they are stressed by high heat loads. Global warming since the last ice age reduced the geographic distribution of some of the 15 species of marmots. Recent warming resulted in a movement upslope of their lower elevation boundary. This process likely will continue because warming is associated with drier unpalatable vegetation. Drought reduces reproduction and increases mortality;thus decreased summer rainfall in the montane environments where marmots live may cause local extinction. Snow cover, a major environmental factor, is essential to insulate hibernation burrows from low, stressful temperatures. However, prolonged vernal snow cover reduces reproduction and increases mortality. Montane areas currently lacking marmot populations because vernal snow cover persists beyond the time that marmots must begin foraging may become colonized if warming causes earlier snow melt. This benefit will be short-lived because decreased precipitation likely will result in unpalatable vegetation. Although some marmot populations are physiologically adapted to a warmer climate, global warming will increase too rapidly for any significant evolutionary response to dryness. The species that live in high, alpine meadows where tree and shrub invasions occur are most threatened with extinction. Captive breeding can preserve marmot species in the shortrun, but is impractical over the long-term. Widespread species are unlikely to be endangered in the foreseeable future, but local, low elevation populations will be lost.
文摘This study examines how accurate young adults in the Iraqi Kurdistan Region, as an emerging democracy in the Middle East, express their core values through social media (Facebook in this context). It also explores whether privacy affects with value disclosure. Findings show that value disclosure and definition of privacy varied greatly among respondents and from one value to another. Based on in-depth interview with 12 young adults, the study finds that religious, social, and cultural values have been easily and freely expressed on Facebook accounts by the majority of young adults, whereas other values such as honesty, freedom of speech, and political beliefs are being held by others mainly for privacy issues and political reasons. Democracy was a core value for some young adults seeking to make sense of the western principles of democracy and that reflect on their Facebook account. Results suggest that male respondents practice more freedom and less caution about their privacy than the female respondents on Facebook.
文摘After successfully locating one abandoned brine well by an electromagnetic method during testing in 2001 and five abandoned brine wells by a high resolution magnetic method during 2002, a high resolution magnetic method was again proposed to search for wells in 2003 when a second sensor was employed to acquire data for calculating the pseudo vertical gradient of magnetic fields. Total area surveyed in 2003 was 1,024,000 ft 2, which was divided into grids with an average size of 10,000 ft 2 and distributed across eight different sites. Magnetic anomalies and their vertical gradients from known brine wells were first recorded as signatures to identify anomalies caused by possible buried brine wells. Of fifty one verified anomalies, thirty one anomalies were due to wells buried at depths from 0 to 8.5 ft: twenty one 6 to 9 inch abandoned brine wells, seven 1.5 to 3 inch probable water wells, one 16 inch dewatering well for a construction site at a depth of 3 ft, and two 4 inch wells on the ground surface. Approximate monopole shaped anomalies were observed from all these wells after data corrections. However, the range of amplitudes of magnetic anomalies from 7,000 to 28,000 nT from these abandoned brine wells was measured. This range of anomalies is mainly due to the thickness and depth of buried wells. Anomaly amplitudes from 1.5 to 3 inch wells are 4,000 to 8,000 nT and linearly correlate with the buried depth. One 3 inch well that caused an anomaly of 13,000 nT could be the inner pipe of a brine well. Gradient anomalies are roughly in a range of 100 to 200 nT/inch for 1.5 to 3 inch wells and 200 to 300 nT/inch for brine wells.As indicated by the potential field theory, gradient data possess higher horizontal resolution than the magnetic field itself. Gradient data provide valuable assistance in determining horizontal locations of anomaly sources for excavation. In practice, however, improvement in the horizontal resolution is limited by survey line spacing. If only one sensor is used in a survey, there is rapid decrease in the horizontal resolution when sensor height increases from 14 to 44 inches. This indicates that it is critical to keep the sensor as close to the ground as possible when hunting buried wells that are close to each other. It also suggests that the downward continuation is useful to increase the horizontal resolution in well hunting.
基金supported by the National Natural Science Foundation of China (Grant No.30370282)Educational Commission of Hubei Province of China (Q20082201)Talent Introduction Funds of Hubei Normal University (2007F13)
文摘Ammopiptanthus nanus is an endangered evergreen shrub endemic to the deserts of central Asia and plays an important role in delaying further desertification. We examined allozyme variation and AFLP diversity in A. nanus populations and investigated the mating system of this species using progeny arrays assayed for polymorphic allozyme loci. Mating system analysis in the Keyi'eryongke'er population showed low levels of outcrossing, and strong inbreeding depression. Low levels of genetic variation were detected at both population (allozyme, Pp=14.0%, A=l.14, He=0.031; AFLP, Pp=14.5%, Shannon's information index I=0.063) and species (allozyme, Pp=21.1%, A=1.21, He=0.040; AFLP, Pp=20.9%, I=0.083) levels; while moderate genetic differentiation existed among populations, as indicated by allozymes (Gsa-=0.081) and AFLP (GST=0.151-0.193). Founder effect, bottlenecks in evolutionary history, the mixed mating system and co-ancestry may have influenced the level of genetic diversity in A. nanus. Markers of both types provide new insights for conservation management, indicating that the Biao'ertuokuoyi and Keyi'eryongke'er populations should be given priority for in situ conservation and regarded as seed sources for ex situ conservation.
文摘In-situ gelation of aqueous sulfomethylated resorcinol formaldehyde (SMRF) system inBerea core has been investigated. Two sets of displacement experiments were conducted with thissystem (containing 5% NaCl, 0. 036% CaCl_2. 2H_2O). The brine permeabilities of the coreswere reduced significantly from about 600 to 0.1 md. The in-situ gelation in Berea core occurreda little bit earlier than gelation anticipated from bulk test in the experiments. The gel time waseasier to control at initial pH between 6 and 8. During injection of SMRF system, the apparentviscosity was less than 1 mPa·s at 41℃.
文摘Factors affecting the gelation of resorcinol-formaldehyde systems have been examined overvariable ranges applicable to oilfield use. Gelation of resorcinol-formaldehyde (RF) system wassensitive to pH,salinity and hardness. Generally,this gel system could be used in fresh water orlow salinity brine at pH higher than about 9. The application would require careful monitoring ofinjection fluids to avoid premature gelation or prolonged shut-in times,especially under conditionsof low salinity and high pH. Salinity and hardness compatibilities of the system were improved bysulfomethylation of resorcinol. Aqueous sulfomethylated resorcinol formaldehyde (SMRF)system could be used in brine with higher salinity and hardness and at a wider pH range of 5--10.
文摘This paper considers conservation and balance laws and the constitutive theories for non-classical viscous fluent continua without memory, in which internal rotation rates due to the velocity gradient tensor are incorporated in the thermodynamic framework. The constitutive theories for the deviatoric part of the symmetric Cauchy stress tensor and the Cauchy moment tensor are derived based on integrity. The constitutive theories for the Cauchy moment tensor are considered when the balance of moments of moments 1) is not a balance law and 2) is a balance law. The constitutive theory for heat vector based on integrity is also considered. Restrictions on the material coefficients in the constitutive theories for the stress tensor, moment tensor, and heat vector are established using the conditions resulting from the entropy inequality, keeping in mind that the constitutive theories derived here based on integrity are in fact nonlinear constitutive theories. It is shown that in the case of the simplest linear constitutive theory for stress tensor used predominantly for compressible viscous fluids, Stokes' hypothesis or Stokes'?assumption has no thermodynamic basis, hence may be viewed incorrect. Thermodynamically consistent derivations of the restrictions on various material coefficients are presented for non-classical as well as classical theories that are applicable to nonlinear constitutive theories, which are inevitable if the constitutive theories are derived based on integrity.
文摘Evaluation of the conspicuity of roadway environments for their environmental impact on driving performance is vital for roadway safety. Existing meters and tools for roadway measurements cannot record light and geometry data simultaneously in a high resolution. This study introduced a new method that adopted recently developed high dynamic range (HDR) photogrammetry to measure the luminance and XYZ coordinates of millions of points across a road scene with the same device—a camera, and a MatLab code for data treatment and visualization. To validate this method, the roadway environments of a straight and flat section of Jayhawk Boulevard (482.8 m long) at Lawrence, KS and a roundabout (15.3 m in diameter) at its end were measured under clear and cloudy sky in the daytime and at nighttime with dry and wet pavements. Eight HDR images of the roadway environments under different viewing conditions were generated using the HDR photogrammetric techniques and calibrated. From each HDR image, synchronous light and geometry data were extracted in Radiance and further analyzed to identify potential roadway environmental hazards using the MatLab code (http://people.ku.edu/~h717c996/research.html). The HDR photogrammetric measurement with current equipment had a margin of errors for geometry measurement that varied with the measuring distance, averagely 23.1% - 27.5% for the Jayhawk Boulevard and 9.3% - 16.2% for the roundabout. The accuracy of luminance measurement was proven in the literature as averagely 1.5% - 10.1%. The camera-aided measurement is fast, non-contact, non-destructive, and off the road, thus, it is deemed more efficient and safer than conventional ways using meters and tools. The HDR photogrammetric techniques with current equipment still need improvements on accuracy and speed of the data treatment.
文摘This project was intended to determine whether the preprogrammed time-varying recharge protocol for a battery incased in a neuromodulation implant can give rise to tissue temperatures that surpass a safe level or are otherwise benign. The study included the development of a highly accurate model of all the thermal processes that are activated by the recharging of the battery contained within the neuromodulation implant. The model was implemented by numerical simulations performed for several realistic operating conditions. The computed spatial and temporal tissue temperature distributions were employed to estimate possible tissue damage by making use of two independent methodologies. Independent calorimeter-based experiments were performed to provide validation for the calculated rates of heat generation in the coils of the implant. Spatial and temporal tissue temperature distributions extracted from the numerical simulations revealed the thermal effects associated with several realistic operating protocols. None of the operating protocols gave rise to temperatures above 42℃. Numerical values of thermal tissue damage metrics were determined and compared with accepted values which correspond to the absence and the presence of tissue damage. The experimentally determined rate of heat generation in the implant coils validated that from electrical measurements to within 2%. Both the tissue temperature results and the thermal damage metrics found no evidence of tissue injury when time-varying preprogrammed protocols are used in the recharging of neuromodulation implant-encased batteries.
基金the National Institute of Standards and Technology(NIST)Center of Excellence for Risk-Based Community Resilience Planning under Cooperative Agreement 70NANB20H008 and 70NANB15H044 between NISTColorado State University.The contents expressed in this paper are the views of the authors and do not necessarily represent the opinions or views of NIST or the U.S Department of Commerce.
文摘Hurricane-induced hazards can result in significant damage to the built environment cascading into major impacts to the households,social institutions,and local economy.Although quantifying physical impacts of hurricane-induced hazards is essential for risk analysis,it is necessary but not sufficient for community resilience planning.While there have been several studies on hurricane risk and recovery assessment at the building-and community-level,few studies have focused on the nexus of coupled physical and social disruptions,particularly when char-acterizing recovery in the face of coastal multi-hazards.Therefore,this study presents an integrated approach to quantify the socio-physical disruption following hurricane-induced multi-hazards(e.g.,wind,storm surge,wave)by considering the physical damage and functionality of the built environment along with the population dynamics over time.Specifically,high-resolution fragility models of buildings,and power and transportation infrastructures capture the combined impacts of hurricane loading on the built environment.Beyond simulat-ing recovery by tracking infrastructure network performance metrics,such as access to essential facilities,this coupled socio-physical approach affords projection of post-hazard population dislocation and temporal evolution of housing and household recovery constrained by the building and infrastructure recovery.The results reveal the relative importance of multi-hazard consideration in the damage and recovery assessment of communities,along with the role of interdependent socio-physical system modeling when evaluating metrics such as housing recovery or the need for emergency shelter.Furthermore,the methodology presented here provides a foundation for resilience-informed decisions for coastal communities.
文摘Conflicts between supply chain members emerge because individual strategic actions may not be jointly optimal.Efforts to forecast consumer demand represent a source of conflict.The coordination of forecasts requires a powerful incentive alignment approach.This work proposes a smart contract equipped consortium blockchain system that creates an incentive structure that makes coordination with respect to forecasts economically appealing.Distortions of demand information due to uncoordinated forecasting are captured by a bullwhip measure that factors both forecast error and variance.Cooperation under the system is shown to help minimize this bullwhip measure,thus generating new outcomes for the participants that allow for a higher reward.Under a fixed payout structure,the system achieves credibility of continued cooperation,thus promoting an optimally coordinated equilibrium between the retailer and supplier.Blockchain technology represents a novel information system and consensus formation mechanism that can intermediate the behavior of a supply chain network.
基金Part of this work was funded by a NIHgrant AG165904 to Michael Ferkin,a Sigma Xi grant and a University of Memphis Society fellowship to BrianSchilling,and a grant fromthe National Strength and Conditioning Associationto AndrewFry.
基金NCHRP Project,IDEA 223:Fatigue Crack Inspection using Computer Vision and Augmented Reality。
文摘Fatigue cracks that develop in civil infrastructure such as steel bridges due to repetitive loads pose a major threat to structural integrity.Despite being the most common practice for fatigue crack detection,human visual inspection is known to be labor intensive,time-consuming,and prone to error.In this study,a computer vision-based fatigue crack detection approach using a short video recorded under live loads by a moving consumer-grade camera is presented.The method detects fatigue crack by tracking surface motion and identifies the differential motion pattern caused by opening and closing of the fatigue crack.However,the global motion introduced by a moving camera in the recorded video is typically far greater than the actual motion associated with fatigue crack opening/closing,leading to false detection results.To overcome the challenge,global motion compensation(GMC)techniques are introduced to compensate for camera-induced movement.In particular,hierarchical model-based motion estimation is adopted for 2D videos with simple geometry and a new method is developed by extending the bundled camera paths approach for 3D videos with complex geometry.The proposed methodology is validated using two laboratory test setups for both in-plane and out-of-plane fatigue cracks.The results confirm the importance of motion compensation for both 2D and 3D videos and demonstrate the effectiveness of the proposed GMC methods as well as the subsequent crack detection algorithm.
基金granted by the Ethics Committee of University of Kansas(10-30-2012/HSCL#20495).
文摘This study examined electromyographic amplitude(EMGRMS)-force relationships during repeated submaximal knee extensor muscle actions among chronic aerobically-(AT),resistance-trained(RT),and sedentary(SED)individuals.Fifteen adults(5/group)attempted 20 isometric trapezoidal muscle actions at 50%of maximal strength.Surface electromyography(EMG)was recorded from vastus lateralis(VL)during the muscle actions.For the first and last successfully completed contractions,linear regression models were fit to the log-transformed EMGRMS-force relationships during the linearly increasing and decreasing segments,and the b terms(slope)and a terms(antilog of y-intercept)were calculated.EMGRMS was averaged during steady force.Only the AT completed all 20 muscle actions.During the first contraction,the b terms for RT(1.3010.197)were greater than AT(0.9100.123;p?0.008)and SED(0.9120.162;p?0.008)during the linearly increasing segment,and in comparison to the linearly decreasing segment(1.0180.139;p?0.014),respectively.For the last contraction,the b terms for RT were greater than AT during the linearly increasing(RT?1.3730.353;AT?0.8830.129;p?0.018)and decreasing(RT?1.5260.328;AT?0.9700.223;p?0.010)segments.In addition,the b terms for SED increased from the linearly increasing(0.9680.144)to decreasing segment(1.2680.126;p?0.015).There were no training,segment,or contraction differences for the a terms.EMGRMS during steady force increased from the first-([64.0851.68]μV)to last-contraction([86.7349.55]μV;p?0.001)collapsed across training statuses.The b terms differentiated the rate of change for EMGRMS with increments in force among training groups,indicating greater muscle excitation to the motoneuron pool was necessary for the RT than AT during the linearly increasing and decreasing segments of a repetitive task.