A series of investigations were conducted using sequencing batch biofilm reactor（SBBR） to explore the influence of C：N：P ratio on biological dephosphatation including the denitrifying dephosphatation and the denit...A series of investigations were conducted using sequencing batch biofilm reactor（SBBR） to explore the influence of C：N：P ratio on biological dephosphatation including the denitrifying dephosphatation and the denitrification process.Biomass in the reactor occurred mainly in the form of a biofilm attached to completely submerged disks.Acetic acid was used as the source of organic carbon.C：N：P ratios have had a significant effect on the profiles of phosphate release and phosphate uptake and nitrogen removal.The highest rates of phosphate release and phosphate uptake were recorded at the C：N：P ratio of 140：70：7.The C：N ratio of 2.5：1 ensured complete denitrification.The highest rate of denitrification was achieved at the C：N：P ratio of 140：35：7.The increase of nitrogen load caused an increase in phosphates removal until a ratio C：N：P of 140：140：7.Bacteria of the biofilm exposed to alternate conditions of mixing and aeration exhibited enhanced intracellular accumulation of polyphosphates.Also,the structure of the biofilm encouraged anaerobic-aerobic as well as anoxic-anaerobic and absolutely anaerobic conditions in a SBBR.These heterogeneous conditions in the presence of nitrates may be a significant factor determining the promotion of denitrifying polyphosphate accumulating organism（DNPAO） development.展开更多
A broader consensus on the number of ground motions to be used and the method of scaling to be adopted for nonlinear response history analysis （RHA） of structures is yet to be reached. Therefore, in this study, the ...A broader consensus on the number of ground motions to be used and the method of scaling to be adopted for nonlinear response history analysis （RHA） of structures is yet to be reached. Therefore, in this study, the effects of selection and scaling of ground motions on the response of seismically isolated structures, which are routinely designed using nonlinear RHA, are investigated. For this purpose, isolation systems with a range of properties subjected to bidirectional excitation are considered. Benchmark response of the isolation systems is established using large sets of unscaled ground motions systematically categorized into pulse-like, non-pulse-like, and mixed set of motions. Different subsets of seven to 14 ground motions are selected from these large sets using （a） random selection and （b） selection based on the best match of the shape of the response spectrum of ground motions to the target spectrum. Consequences of weighted scaling （also commonly referred to as amplitude scaling or linear scaling） as well as spectral matching are investigated. The ground motion selection and scaling procedures are evaluated from the viewpoint of their accuracy, efficiency, and consistency in predicting the benchmark response. It is confirmed that seven time histories are sufficient for a reliable prediction of isolation system displacement demands, for all ground motion subsets, selection and scaling procedures, and isolation systems considered. If ground motions are selected based on their best match to the shape of the target response spectrum （which should be preferred over randomly selected motions）, weighted scaling should be used if pulse-like motions are considered, either of weighted scaling or spectral matching can be used if non-pulse-like motions are considered, and an average of responses from weighted-scaled and spectrum-matched ground motions should be used for a mixed set of motions. On the other hand, the importance of randomly selected motions in representing inherent variability of response is recognized and it is found that weighted scaling is more appropriate for such motions.展开更多
Understanding rock strength is essential when undertaking major excavation projects,as accurate assessments ensure both safe and cost-effective engineered slopes.Balancing the cost-safety trade-off becomes more impera...Understanding rock strength is essential when undertaking major excavation projects,as accurate assessments ensure both safe and cost-effective engineered slopes.Balancing the cost-safety trade-off becomes more imperative during the construction of critical infrastructure such as nuclear power stations,where key components are built within relatively deep excavations.Designing these engineered slopes is reliant on rock strength models,which are generally parameterised using estimates of rock properties(e.g.unconfined compressive strength,rock disturbance)measured prior to the commencement of works.However,the physical process of excavation weakens the remaining rock mass.Therefore,the model also requires an adjustment for the anticipated rock disturbance.In practice,this parameter is difficult to quantify and as a result it is often poorly constrained.This can have a significant impact on the final design and cost of excavation.We present results from passive and active seismic surveys,which image the extent and degree of disturbance within recently excavated slopes at the construction site of Hinkley Point C nuclear power station.Results from active seismic surveys indicate that the disturbance is primarily confined to 0.5 m from the excavated face.In conjunction,passive monitoring is used to detected seismic events corresponding to fracturing on the cm-scale and event locations are in agreement with 0.5 m of disturbance into the rock face.This suggests rock disturbance at this site is relatively low and occurred during and immediately after the excavation.A ratio of seismic velocities recorded before and after excavations are used to determine the disturbance parameter required for the Hoek eBrown rock failure criterion,and we assess that rock disturbance is low with the magnitude of the disturbance diminishing more quickly than expected into the excavated slope.Seismic methods provide a low-cost and quick method to assess excavation related rock mass disturbance,which can lead to cost reductions in large excavation projects.展开更多
Integration of unpredictable renewable power sources into the Grid is leading to the development of wide area control algorithms and smart grid. Smart meters are the first step in the building a smart consumer interfa...Integration of unpredictable renewable power sources into the Grid is leading to the development of wide area control algorithms and smart grid. Smart meters are the first step in the building a smart consumer interface. Much more, however, would be required in building a smart grid than just smart meters. This paper explores the conceptual architecture of smart grid. It highlights the need for additional infrastructure to realize full potential of smart grid. The information presented in this paper is an attempt to uncover what the future in smart grid could be and what infrastructure would be required to tap its potential. As smart grid evolves, more functionality would be built in the constituents. The paper also proposes mathematical basis for some of the controller algorithms.展开更多
Huntsman Lake is located within the Middle Run of the Pohick Creek watershed, which is itself located within the much larger Chesapeake Bay watershed. Data collected from both the water column and the lake＇s sediment...Huntsman Lake is located within the Middle Run of the Pohick Creek watershed, which is itself located within the much larger Chesapeake Bay watershed. Data collected from both the water column and the lake＇s sediments indicate that phosphorus-rich bottom sediments are an important internal loading source, and these internal phosphorus loads would continue to adversely impact water quality until and unless sediments are removed or inactivated. The implementation of artificial circulation was anticipated to be able to increase the sequestration of phosphorus within better oxygenated bottom sediments, and was the first lake management strategy deployed in Huntsman Lake. In the first two years after the installation of a whole-lake circulation system, the lake＇s waters are no longer stratified, and the bottom waters are no longer hypoxic and/or anoxic. While there is no evidence of a subsequent reduction in concentrations of nitrogen or chlorophyll-a, average phosphorus concentrations have decreased. However, high variability in the phosphorus data decreases our confidence that this is a sustained improvement. These results are consistent with prior findings, including those from downstream systems, that the reversal of the symptoms of eutrophication can involve lag-periods up to several years, if they are successful at all.展开更多
The Sunshine Lake/Sunrise Waterway System, located in Southwest Florida （USA） previously experienced extensive and persistent algal blooms, with noxious odors and deep organic-rich sediments. This algal bloom was ad...The Sunshine Lake/Sunrise Waterway System, located in Southwest Florida （USA） previously experienced extensive and persistent algal blooms, with noxious odors and deep organic-rich sediments. This algal bloom was addressed via a lake-wide dredging project to remove the material from the lake bottom. A contributing factor to the algal bloom is elevated phosphorus in stormwater runoff, likely due to naturally phosphorus-rich geology in the surrounding watershed. Due to the naturally elevated phosphorus supply, excessive nutrient loads will likely continue in the future. An ongoing monitoring program, initiated after the dredging of the lake, determined that a type of algae （Chara sp,） other than that which caused the initial bloom had established itself by October 2015. This plant biomass is considered an alternative destination for incoming nutrient loads, and as such should be managed, rather than eliminated via the use of herbicides. The abundance and nutrient content of the mass of Chara sp. in the lake and waterway was estimated, and the amount of external nutrient load that would be removed from the lake with physical harvesting of Chara sp. was quantified. The cost-effectiveness of nutrient removal via physical harvesting of Chara sp. was then compared against typical stormwater treatment ponds.展开更多
Although commonly used, no design method is available for steel web tapered tee section cantilevers. This paper investigates the bending stresses of such beams. Relationships between the maximum compressive stress and...Although commonly used, no design method is available for steel web tapered tee section cantilevers. This paper investigates the bending stresses of such beams. Relationships between the maximum compressive stress and the degree of taper were investigated. An analytical model is presented to determine the location of the maximum stress when subjected to a uniformly distributed load or a point load at the free end and was validated using finite element analysis and physical tests. It was found that the maximum stress always occurs at the support when subjected to a uniformly distributed load. When subjected to a point load at the free end and the degree of taper is up to seven, it was found that Miller＇s equation could be used to determine the location of the maximum stress. However, it is shown that when the degree of taper is greater than seven, Miller＇s equation does not accurately predict the location and the analytical model should be used. It was also found that the location of the maximum stress was solely dependent on the degree of taper, while a geometric ratio, fl was required to determine the magnitude of the maximum stress. A simple method that predicts the magnitude of the maximum stress is proposed. The average error in the prediction of the magnitude of the maximum stress is found to be less than 1.0%.展开更多
Focal adhesions are critical cell membrane components that regulate adhesion and migration and have cluster dimensions that correlate closely with adhesion engagement and migration speed.We utilized a label-free appro...Focal adhesions are critical cell membrane components that regulate adhesion and migration and have cluster dimensions that correlate closely with adhesion engagement and migration speed.We utilized a label-free approach for dynamic,long-term,quantitative imaging of cell–surface interactions called photonic resonator outcoupler microscopy(PROM)in which membrane-associated protein aggregates outcoupled photons from the resonant evanescent field of a photonic crystal biosensor,resulting in a highly localized reduction of the reflected light intensity.By mapping the changes in the resonant reflected peak intensity from the biosensor surface,we demonstrate the ability of PROM to detect focal adhesion dimensions.Similar spatial distributions can be observed between PROM images and fluorescence-labeled images of focal adhesion areas in dental epithelial stem cells.In particular,we demonstrate that cell–surface contacts and focal adhesion formation can be imaged by two orthogonal label-free modalities in PROM simultaneously,providing a general-purpose tool for kinetic,high axial-resolution monitoring of cell interactions with basement membranes.展开更多
ChatGPT has emerged as a promising advanced large language model that needs prompt to gain information.However,designing a good prompt is not an easy task for many end-users.Therefore,this study intends to determine t...ChatGPT has emerged as a promising advanced large language model that needs prompt to gain information.However,designing a good prompt is not an easy task for many end-users.Therefore,this study intends to determine the amount of information gained because of varied amounts of information in the prompt.This study used two types of prompts,initial and improved,to query the introduction sections of 327 highly cited articles on traffic safety.The queried introduction sections were then matched with the corresponding human-written introduction sections from the same articles.Similarity tests and text network analysis were used to understand the level of similarities and the content of ChatGPT-generated and human-written introductions.The findings indicate the improved prompts,which have the addition of generic persona and information about the citations and references,changed the ChatGPT's output insignificantly.While the perfect similar contents are supposed to have a 1.0 similarity score,the initial and improved prompt's introduction materials have average similarity scores of 0.5387 and 0.5567,respectively.Further,the content analysis revealed that themes such as statistics,trends,safety measures,and safety technologies are more likely to have high similarity scores,irrespective of the amount of information provided in the prompt.On the other hand,themes such as human behavior,policy and regulations,public perception,and emerging technologies require a detailed level of information in their prompt to produce materials that are close to human-written materials.The prompt engineers can use the findings to evaluate their outputs and improve their prompting skills.展开更多
基金funded by the National Science Centre,Poland (the decision nr DEC-2012/07/N/ST8/03201)
文摘A series of investigations were conducted using sequencing batch biofilm reactor（SBBR） to explore the influence of C：N：P ratio on biological dephosphatation including the denitrifying dephosphatation and the denitrification process.Biomass in the reactor occurred mainly in the form of a biofilm attached to completely submerged disks.Acetic acid was used as the source of organic carbon.C：N：P ratios have had a significant effect on the profiles of phosphate release and phosphate uptake and nitrogen removal.The highest rates of phosphate release and phosphate uptake were recorded at the C：N：P ratio of 140：70：7.The C：N ratio of 2.5：1 ensured complete denitrification.The highest rate of denitrification was achieved at the C：N：P ratio of 140：35：7.The increase of nitrogen load caused an increase in phosphates removal until a ratio C：N：P of 140：140：7.Bacteria of the biofilm exposed to alternate conditions of mixing and aeration exhibited enhanced intracellular accumulation of polyphosphates.Also,the structure of the biofilm encouraged anaerobic-aerobic as well as anoxic-anaerobic and absolutely anaerobic conditions in a SBBR.These heterogeneous conditions in the presence of nitrates may be a significant factor determining the promotion of denitrifying polyphosphate accumulating organism（DNPAO） development.
文摘A broader consensus on the number of ground motions to be used and the method of scaling to be adopted for nonlinear response history analysis （RHA） of structures is yet to be reached. Therefore, in this study, the effects of selection and scaling of ground motions on the response of seismically isolated structures, which are routinely designed using nonlinear RHA, are investigated. For this purpose, isolation systems with a range of properties subjected to bidirectional excitation are considered. Benchmark response of the isolation systems is established using large sets of unscaled ground motions systematically categorized into pulse-like, non-pulse-like, and mixed set of motions. Different subsets of seven to 14 ground motions are selected from these large sets using （a） random selection and （b） selection based on the best match of the shape of the response spectrum of ground motions to the target spectrum. Consequences of weighted scaling （also commonly referred to as amplitude scaling or linear scaling） as well as spectral matching are investigated. The ground motion selection and scaling procedures are evaluated from the viewpoint of their accuracy, efficiency, and consistency in predicting the benchmark response. It is confirmed that seven time histories are sufficient for a reliable prediction of isolation system displacement demands, for all ground motion subsets, selection and scaling procedures, and isolation systems considered. If ground motions are selected based on their best match to the shape of the target response spectrum （which should be preferred over randomly selected motions）, weighted scaling should be used if pulse-like motions are considered, either of weighted scaling or spectral matching can be used if non-pulse-like motions are considered, and an average of responses from weighted-scaled and spectrum-matched ground motions should be used for a mixed set of motions. On the other hand, the importance of randomly selected motions in representing inherent variability of response is recognized and it is found that weighted scaling is more appropriate for such motions.
文摘Understanding rock strength is essential when undertaking major excavation projects,as accurate assessments ensure both safe and cost-effective engineered slopes.Balancing the cost-safety trade-off becomes more imperative during the construction of critical infrastructure such as nuclear power stations,where key components are built within relatively deep excavations.Designing these engineered slopes is reliant on rock strength models,which are generally parameterised using estimates of rock properties(e.g.unconfined compressive strength,rock disturbance)measured prior to the commencement of works.However,the physical process of excavation weakens the remaining rock mass.Therefore,the model also requires an adjustment for the anticipated rock disturbance.In practice,this parameter is difficult to quantify and as a result it is often poorly constrained.This can have a significant impact on the final design and cost of excavation.We present results from passive and active seismic surveys,which image the extent and degree of disturbance within recently excavated slopes at the construction site of Hinkley Point C nuclear power station.Results from active seismic surveys indicate that the disturbance is primarily confined to 0.5 m from the excavated face.In conjunction,passive monitoring is used to detected seismic events corresponding to fracturing on the cm-scale and event locations are in agreement with 0.5 m of disturbance into the rock face.This suggests rock disturbance at this site is relatively low and occurred during and immediately after the excavation.A ratio of seismic velocities recorded before and after excavations are used to determine the disturbance parameter required for the Hoek eBrown rock failure criterion,and we assess that rock disturbance is low with the magnitude of the disturbance diminishing more quickly than expected into the excavated slope.Seismic methods provide a low-cost and quick method to assess excavation related rock mass disturbance,which can lead to cost reductions in large excavation projects.
文摘Integration of unpredictable renewable power sources into the Grid is leading to the development of wide area control algorithms and smart grid. Smart meters are the first step in the building a smart consumer interface. Much more, however, would be required in building a smart grid than just smart meters. This paper explores the conceptual architecture of smart grid. It highlights the need for additional infrastructure to realize full potential of smart grid. The information presented in this paper is an attempt to uncover what the future in smart grid could be and what infrastructure would be required to tap its potential. As smart grid evolves, more functionality would be built in the constituents. The paper also proposes mathematical basis for some of the controller algorithms.
文摘Huntsman Lake is located within the Middle Run of the Pohick Creek watershed, which is itself located within the much larger Chesapeake Bay watershed. Data collected from both the water column and the lake＇s sediments indicate that phosphorus-rich bottom sediments are an important internal loading source, and these internal phosphorus loads would continue to adversely impact water quality until and unless sediments are removed or inactivated. The implementation of artificial circulation was anticipated to be able to increase the sequestration of phosphorus within better oxygenated bottom sediments, and was the first lake management strategy deployed in Huntsman Lake. In the first two years after the installation of a whole-lake circulation system, the lake＇s waters are no longer stratified, and the bottom waters are no longer hypoxic and/or anoxic. While there is no evidence of a subsequent reduction in concentrations of nitrogen or chlorophyll-a, average phosphorus concentrations have decreased. However, high variability in the phosphorus data decreases our confidence that this is a sustained improvement. These results are consistent with prior findings, including those from downstream systems, that the reversal of the symptoms of eutrophication can involve lag-periods up to several years, if they are successful at all.
文摘The Sunshine Lake/Sunrise Waterway System, located in Southwest Florida （USA） previously experienced extensive and persistent algal blooms, with noxious odors and deep organic-rich sediments. This algal bloom was addressed via a lake-wide dredging project to remove the material from the lake bottom. A contributing factor to the algal bloom is elevated phosphorus in stormwater runoff, likely due to naturally phosphorus-rich geology in the surrounding watershed. Due to the naturally elevated phosphorus supply, excessive nutrient loads will likely continue in the future. An ongoing monitoring program, initiated after the dredging of the lake, determined that a type of algae （Chara sp,） other than that which caused the initial bloom had established itself by October 2015. This plant biomass is considered an alternative destination for incoming nutrient loads, and as such should be managed, rather than eliminated via the use of herbicides. The abundance and nutrient content of the mass of Chara sp. in the lake and waterway was estimated, and the amount of external nutrient load that would be removed from the lake with physical harvesting of Chara sp. was quantified. The cost-effectiveness of nutrient removal via physical harvesting of Chara sp. was then compared against typical stormwater treatment ponds.
文摘Although commonly used, no design method is available for steel web tapered tee section cantilevers. This paper investigates the bending stresses of such beams. Relationships between the maximum compressive stress and the degree of taper were investigated. An analytical model is presented to determine the location of the maximum stress when subjected to a uniformly distributed load or a point load at the free end and was validated using finite element analysis and physical tests. It was found that the maximum stress always occurs at the support when subjected to a uniformly distributed load. When subjected to a point load at the free end and the degree of taper is up to seven, it was found that Miller＇s equation could be used to determine the location of the maximum stress. However, it is shown that when the degree of taper is greater than seven, Miller＇s equation does not accurately predict the location and the analytical model should be used. It was also found that the location of the maximum stress was solely dependent on the degree of taper, while a geometric ratio, fl was required to determine the magnitude of the maximum stress. A simple method that predicts the magnitude of the maximum stress is proposed. The average error in the prediction of the magnitude of the maximum stress is found to be less than 1.0%.
基金supported by the National Science Foundation(NSF)Grant CBET 11-32301National Institutes of Health(NIH)R01 DK099528 and NIH R21 EB018481。
文摘Focal adhesions are critical cell membrane components that regulate adhesion and migration and have cluster dimensions that correlate closely with adhesion engagement and migration speed.We utilized a label-free approach for dynamic,long-term,quantitative imaging of cell–surface interactions called photonic resonator outcoupler microscopy(PROM)in which membrane-associated protein aggregates outcoupled photons from the resonant evanescent field of a photonic crystal biosensor,resulting in a highly localized reduction of the reflected light intensity.By mapping the changes in the resonant reflected peak intensity from the biosensor surface,we demonstrate the ability of PROM to detect focal adhesion dimensions.Similar spatial distributions can be observed between PROM images and fluorescence-labeled images of focal adhesion areas in dental epithelial stem cells.In particular,we demonstrate that cell–surface contacts and focal adhesion formation can be imaged by two orthogonal label-free modalities in PROM simultaneously,providing a general-purpose tool for kinetic,high axial-resolution monitoring of cell interactions with basement membranes.
文摘ChatGPT has emerged as a promising advanced large language model that needs prompt to gain information.However,designing a good prompt is not an easy task for many end-users.Therefore,this study intends to determine the amount of information gained because of varied amounts of information in the prompt.This study used two types of prompts,initial and improved,to query the introduction sections of 327 highly cited articles on traffic safety.The queried introduction sections were then matched with the corresponding human-written introduction sections from the same articles.Similarity tests and text network analysis were used to understand the level of similarities and the content of ChatGPT-generated and human-written introductions.The findings indicate the improved prompts,which have the addition of generic persona and information about the citations and references,changed the ChatGPT's output insignificantly.While the perfect similar contents are supposed to have a 1.0 similarity score,the initial and improved prompt's introduction materials have average similarity scores of 0.5387 and 0.5567,respectively.Further,the content analysis revealed that themes such as statistics,trends,safety measures,and safety technologies are more likely to have high similarity scores,irrespective of the amount of information provided in the prompt.On the other hand,themes such as human behavior,policy and regulations,public perception,and emerging technologies require a detailed level of information in their prompt to produce materials that are close to human-written materials.The prompt engineers can use the findings to evaluate their outputs and improve their prompting skills.
