This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement tech...This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement technique,which is used in Civil Engineering applications to produce calcium carbonate through bacterial or enzymatic activity,replacing the use of other binder materials such as cement or resins,and therefore reducing carbon footprint.The microdevice was used to measure urease activity in the soil interstitial fluid,to investigate if bacterial activity could be affected by the presence of the particles and tortuosity from pore geometry.Such analysis is important to understand biocementation mechanism inside the soil and helps to improve the design of such treatment solutions.The device is basically a squared reservoir printed in polypropylene using a 3D printing machine,incorporating stainless steel electrodes in its base.The electrical resistivity was computed adopting Wenner method,by connecting 4 PCB electrodes to a signal generator and an oscilloscope for measuring the voltage when a AC current of 1 mA was applied.Both square and sinusoidal waves with 5 kHz frequency were selected among other frequencies.The measurements were adjusted during the calibration of the microdevice,done using standard salt solutions with known electrical conductivity measured using an electrical conductivity probe.For the bacterial activity measurements,the bacterial and urea solutions were added to a uniform-graded size quarzitic sand(average diameter 0.3 mm)placed inside the microdevice and covering completely the electrodes.Bacterial activity was not affected by the presence of the sand,which confirms that this treatment is effective for this type of soils.展开更多
China is rich in geothermal resources,especially in Fujian Province,where 207 exposed hot springs have been discovered.The maximum temperature recorded in geothermal wells is above 121℃ in this province,indicating a ...China is rich in geothermal resources,especially in Fujian Province,where 207 exposed hot springs have been discovered.The maximum temperature recorded in geothermal wells is above 121℃ in this province,indicating a high geothermal resource potential.However,large-scale breakthroughs in geothermal exploration are hindered by a lack of clear geothermal genetic models.In this study,the genetic model of a faultcontrolled mediumelow-temperature convection geothermal zone in the Fujian coastal area was determined by considering the tectonic characteristics of the area and the hydrochemical characteristics of the geothermal fluid(recharge,runoff and discharge characteristics,geothermal reservoir temperature,geothermal fluid circulation depth and renewability).The results showed that the exposed hot springs and high-temperature geothermal boreholes were concentrated in the Fu'aneNanjing and ChangleeZhao'an fault zones.At the intersection or faultbend of these two fault zones,there was strong stress release and activity,as demonstrated in the exposed parts of the high-temperature geothermal resources.The ChangleeZhao'an fault zone had a greater circulation depth,with an average heat storage temperature of 140℃,reflecting high geothermal resource potential.Considering the current temperature of the hot springs,Xiamen Bay and NanjingeJiulong River were identified as the next geothermal development zones.展开更多
This paper summarizes the development of hydro-projects in China,blended with an international perspective.It expounds major technical progress toward ensuring the safe construction of high dams and river harnessing,a...This paper summarizes the development of hydro-projects in China,blended with an international perspective.It expounds major technical progress toward ensuring the safe construction of high dams and river harnessing,and covers the theorization of uneven non-equilibrium sediment transport,inter-basin water diversion,giant hydro-generator units,pumped storage power stations,underground caverns,ecological protection,and so on.展开更多
Floods are one of nature's most destructive disasters because of the immense damage to land,buildings,and human fatalities.It is difficult to forecast the areas that are vulnerable to flash flooding due to the dyn...Floods are one of nature's most destructive disasters because of the immense damage to land,buildings,and human fatalities.It is difficult to forecast the areas that are vulnerable to flash flooding due to the dynamic and complex nature of the flash floods.Therefore,earlier identification of flash flood susceptible sites can be performed using advanced machine learning models for managing flood disasters.In this study,we applied and assessed two new hybrid ensemble models,namely Dagging and Random Subspace(RS)coupled with Artificial Neural Network(ANN),Random Forest(RF),and Support Vector Machine(SVM)which are the other three state-of-the-art machine learning models for modelling flood susceptibility maps at the Teesta River basin,the northern region of Bangladesh.The application of these models includes twelve flood influencing factors with 413 current and former flooding points,which were transferred in a GIS environment.The information gain ratio,the multicollinearity diagnostics tests were employed to determine the association between the occurrences and flood influential factors.For the validation and the comparison of these models,for the ability to predict the statistical appraisal measures such as Freidman,Wilcoxon signed-rank,and t-paired tests and Receiver Operating Characteristic Curve(ROC)were employed.The value of the Area Under the Curve(AUC)of ROC was above 0.80 for all models.For flood susceptibility modelling,the Dagging model performs superior,followed by RF,the ANN,the SVM,and the RS,then the several benchmark models.The approach and solution-oriented outcomes outlined in this paper will assist state and local authorities as well as policy makers in reducing flood-related threats and will also assist in the implementation of effective mitigation strategies to mitigate future damage.展开更多
Based on systematic experiments on the influence of air entrainment on rock block stability in plunge pools impacted by high-velocity jets,this study presents adaptations of a physically based scour model.The modifica...Based on systematic experiments on the influence of air entrainment on rock block stability in plunge pools impacted by high-velocity jets,this study presents adaptations of a physically based scour model.The modifications regarding jet aeration are implemented in the Comprehensive Scour Model(CSM),allowing it to reproduce the physical-mechanical processes involved in scour formation concerning the three phases;namely,water,rock,and air.The enhanced method considers the reduction of momentum of an aerated jet as well as the decrease of energy dissipation in the jet diffusive shear layer,both resulting from the entrainment of air bubbles.Block ejection from the rock mass depends on a combination of the aerated time-averaged pressure coefficient and the modified maximum dynamic impulsion coefficient,which was found to be a constant value of 0.2 for high-velocity jets in deep pools.The modified model is applied to the case of the observed scour hole at the Kariba Dam,with good agreement.展开更多
The Weiquan Ag-polymetallic deposit is located on the southern margin of the Central Asian Orogenic Belt and in the western segment of the Aqishan-Yamansu arc belt in East Tianshan,northwestern China. Its orebodies, c...The Weiquan Ag-polymetallic deposit is located on the southern margin of the Central Asian Orogenic Belt and in the western segment of the Aqishan-Yamansu arc belt in East Tianshan,northwestern China. Its orebodies, controlled by faults, occur in the lower Carboniferous volcanosedimentary rocks of the Yamansu Formation as irregular veins and lenses. Four stages of mineralization have been recognized on the basis of mineral assemblages, ore fabrics, and crosscutting relationships among the ore veins. Stage I is the skarn stage(garnet + pyroxene), Stage Ⅱ is the retrograde alteration stage(epidote + chlorite + magnetite ± hematite 士 actinolite ± quartz),Stage Ⅲ is the sulfide stage(Ag and Bi minerals + pyrite + chalcopyrite + galena + sphalerite + quartz ± calcite ± tetrahedrite),and Stage IV is the carbonate stage(quartz + calcite ± pyrite). Skarnization,silicification, carbonatization,epidotization,chloritization, sericitization, and actinolitization are the principal types of hydrothermal alteration. LAICP-MS U-Pb dating yielded ages of 326.5±4.5 and 298.5±1.5 Ma for zircons from the tuff and diorite porphyry, respectively. Given that the tuff is wall rock and that the orebodies are cut by a late diorite porphyry dike, the ages of the tuff and the diorite porphyry provide lower and upper time limits on the age of ore formation. The δ13C values of the calcite samples range from-2.5‰ to 2.3‰, the δ18OH2 Oand δDVSMOWvalues of the sulfide stage(Stage Ⅲ) vary from 1.1‰ to 5.2‰ and-111.7‰ to-66.1‰, respectively,and the δ13C, δ18OH2 Oand δDV-SMOWvalues of calcite in one Stage IV sample are 1.5‰,-0.3‰, and-115.6‰, respectively. Carbon, hydrogen, and oxygen isotopic compositions indicate that the ore-forming fluids evolved gradually from magmatic to meteoric sources. The δ34SV-CDTvalues of the sulfides have a large range from-6.9‰ to 1.4‰, with an average of-2.2‰, indicating a magmatic source, possibly with sedimentary contributions. The206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb ratios of the sulfides are 17.9848-18.2785,15.5188-15.6536, and 37.8125-38.4650, respectively, and one whole-rock sample at Weiquan yields206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb ratios of 18.2060, 15.5674, and 38.0511,respectively. Lead isotopic systems suggest that the ore-forming materials of the Weiquan deposit were derived from a mixed source involving mantle and crustal components. Based on geological features, zircon U-Pb dating, and C-H-OS-Pb isotopic data, it can be concluded that the Weiquan polymetallic deposit is a skarn type that formed in a tectonic setting spanning a period from subduction to post-collision. The ore materials were sourced from magmatic ore-forming fluids that mixed with components derived from host rocks during their ascent, and a gradual mixing with meteoric water took place in the later stages.展开更多
The spatial distribution of the world population is uneven,with a density of about 40%living in coastal regions.The trend is expected to continue in both demographic indicators and urban development rate,being many co...The spatial distribution of the world population is uneven,with a density of about 40%living in coastal regions.The trend is expected to continue in both demographic indicators and urban development rate,being many coastal cities in seismic-and tsunami-prone regions and built through informal and unplanned settlements,exposing their population and assets to such hazards.Recent tectonic-triggered events raised awareness of the cascading earthquake and tsunami threat and highlighted the paucity of structural design criteria considering the cumulative effects of both.By being exposed to the ground-motion,the structures’resistance may decrease and become residual/non-existent to support the incoming tsunami,implying an underestimation of the risk.Risk management can benefit from reinforcing the ties between natural hazards and engineering practitioners,linking science and industry,and promoting dialogue between risk analysts and policy-makers.Motivated by the expansion plans of an internationally-sized deep-water port located in a tsunami-prone region,a reflection on the work needed to perform a multi-risk assessment and the challenges yet to overcome is introduced to emphasize the challenge of combining safety requirements with financial and ecologic concerns.A conceptual interdisciplinarybased methodology is proposed to support uncertainty-aware,systematic and informed decisions.展开更多
Temporally fine-grained and objective measures of mental states or their surrogate states are desperately needed in clinical psychiatry. Stress, both acute and especially chronic stress, is an important mental and phy...Temporally fine-grained and objective measures of mental states or their surrogate states are desperately needed in clinical psychiatry. Stress, both acute and especially chronic stress, is an important mental and physiological state observed in many mental disorders. It is a potential precipitant of acute psychiatric decompensations, be they anxious, affective, psychotic, or behavioural. Thus, being able to objectively follow stress or its surrogate parameters over time in a clinician-friendly way would help predict and prevent decompensations and monitor subsequent treatment success. Thus, we introduce the Compound Spectral Stress Indices (CSSI) that are derived from sensing data of various physiological and physiological and behavioural parameters we use as surrogate stress measures. To obtain the CSSI we use a hierarchical approach provided by adaptability, congruency and derived stress coefficient matrices. Adaptability is defined as a macroscopic characterisation of physiological and physiological and behavioural performance constructed as a product of the total variation of time-segmented complexity indices multiplied by the frequency of the time-varying distribution of complexity indices of the measured physiological or physiological and behavioural parameters, where complexity is expressed in terms of the Hurst exponent. Congruency is expressed by a constant characterising a demand-resource balance and it is then expressed in the form of a stress coefficient matrix. The CSSI is given by the spectral distance of the stress coefficient matrices from the ideal demand-resource matrix.展开更多
Aiming at mercury and dioxin in fire coal gas as research objects,nonthermal plasma(NTP)catalytic technology was used to investigate the degradation effect of operating condition parameters on mixed pollutants in mixe...Aiming at mercury and dioxin in fire coal gas as research objects,nonthermal plasma(NTP)catalytic technology was used to investigate the degradation effect of operating condition parameters on mixed pollutants in mixed flue gas condition,and to explore the synergistic degradation of Hg0and TCB(1,2,3-trichlorobenzene,TCB)under mixed flue gas conditions.The research results showed that the conversion efficiency of mercury and TCB increased with the additional output of voltage,and decreased with the increase of the gas flow rate.Under optimal reaction conditions:voltage=17 k V,frequency=300 Hz,gas flow rate=21 min^(-1),the conversion efficiency of Hg^(0)and TCB reached the highest 91.4%and 84.98%,respectively.In the NTP catalytic system,active free radicals played an important role in the synergistic conversion of mercury and TCB,which have a competitive effect,to make the conversion efficiency of mixed pollutants lower than a single substance.In the mixed flue gas condition,the mixed gas has an inhibitory effect on the synergistic conversion of mercury and TCB.Kinetic modeling of NTP catalytic synergistic reaction was established.Under three conditions of TCB,mercury and TCB,mixed simulated flue gas,the NTP catalytic technology showed a quasi-firstorder kinetic reaction for the degradation of TCB.According to the synergistic effect of NTP and composites,the transformation and degradation of TCB mainly included two processes:TCB and ring opening,and Hg^(0)was finally oxidized to Hg^(2+).展开更多
This paper describes the experimental procedure followed to fabricate and validate sol-gel based RH sensors which will be incorporated in soil specimens for standard laboratorial tests. It is the first time such senso...This paper describes the experimental procedure followed to fabricate and validate sol-gel based RH sensors which will be incorporated in soil specimens for standard laboratorial tests. It is the first time such sensors were used for soil suction measurement. They are microfabricated relative humidity sensors (footprint area 11,000 μm × 22,000 μm) operating based on changes in electrical resistivity detected by a cerium doped silica titania film deposited using a sol-gel technique. Their design required gathering experts in several engineering specialties. The working principle of the sensors is based on water vapour equilibrium between the air in the soil and in the sol-gel pores, due to the contact between the two porous materials. The spacing between interdigitated aluminium electrodes was optimized to improve the sensing properties of the sol-gel. The calibration of the different prototypes was done against compacted clay, varying the spacing between 100 and 700 μm. The sensors were also incorporated in soil samples for suction measurement during wetting and drying paths. They were validated by comparing the readings with those from a water dew point potentiometer. From this study it was possible to determine the optimum electrodes spacing of 200 μm. Error was explained by sol-gel heterogeneity effect and by the resolution of the sensing area provided by the electrodes spacing. When comparing with other sensors operating inside soil specimens in standard laboratorial tests, these sol-gel sensors extend the operation range available with the alternative technologies: while conventional tensiometers measure suction ranges from 0 to 1.8 MPa, our sensors demonstrate good results between 1 to 10 MPa (and higher).展开更多
We study the congestion phenomenon in a mathematical model of the data packets traffic in transmission networks as a function of the topology and of the load of the network. Two types of traffic are considered: homoge...We study the congestion phenomenon in a mathematical model of the data packets traffic in transmission networks as a function of the topology and of the load of the network. Two types of traffic are considered: homogeneous and heterogeneous traffic. The congestion phenomenon is studied in stationary conditions through the behaviour of two quantities: the mean travel time of a packet and the mean number of packets that have not reached their destination and are traveling in the network. We define a transformation that maps a network having the small world property (Inet 3037 in our numerical experiments) into a (modified) lattice network that has the same number of nodes. This map changes the capacity of the branches of the graphs representing the networks and can be regarded as an “interpolation” between the two classes of networks. Using this transformation we compare the behaviour of Inet 3037 to the behaviour of a modified rectangular lattice and we study the behaviour of the interpolating networks. This study suggests how to change the network topology and the branch capacities in order to alleviate the congestion phenomenon. In the website: http://www.ceri.uniroma1.it/ceri/zirilli/w6 some auxiliary material including animations and stereo?graphic scenes that helps the understanding of this paper is shown.展开更多
Earth construction,including the use of earth mortars,has been extensively used in the past.However,with the appearance of hydraulic binders,the use of earth strongly decreased for new construction and even to repair ...Earth construction,including the use of earth mortars,has been extensively used in the past.However,with the appearance of hydraulic binders,the use of earth strongly decreased for new construction and even to repair old earth buildings,whose best solution would be the use of compatible materials such as earth mortars.Due to the innumerable advantages of earth and with the growing concern on eco-efficient construction,the interest on earth construction has resurfaced,namely on earth mortars.To optimize the composition of an earth plastering mortar made with a defined clayish earth and two siliceous sands with different particle sizes,six compositions were assessed.Mortars with different volumetric ratios were applied in two different supports(on the back of a tile and on a brick)and planar specimens were also produced.Distinct characteristics were assessed,such as their visual appearance,shrinkage,surface cohesion,surface hardness,dry abrasion resistance,ultrasonic velocity,adhesive strength,and thermal conductivity.It is possible to conclude that a higher clay content in the earth mortar composition increases the shrinkage and occurrence of cracking,the use of fine sand promotes high mass loss by abrasion,and the same mortar applied in different supports behaves differently in terms of durability.展开更多
Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some pa...Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some parts of the globe,there is an imperative need to develop alternative ways to predict it.Therefore,the main objective of this study is to evaluate the performance of different hybrid data-driven techniques in predicting daily GSR in semi-arid regions,such as the majority of Spanish territory.Here,four ensemble-based hybrid models were developed by hybridizing Additive Regression(AR)with Random Forest(RF),Locally Weighted Linear Regression(LWLR),Random Subspace(RS),and M5P.The base algorithms of the developed models are scarcely applied in previous studies to predict solar radiation.The testing phase outcomes demonstrated that the ARRF models outperform all other hybrid models.The provided models were validated by statisticalmetrics,such as the correlation coefficient(R)and root mean square error(RMSE).The results proved that Scenario#6,utilizing extraterrestrial solar radiation,relative humidity,wind speed,and mean,maximum,and minimum ambient air temperatures as the model inputs,leads to the most accurate predictions among all scenarios(R=0.968–0.988 and RMSE=1.274–1.403 MJ/m^(2)・d).Also,Scenario#3 stood in the next rank of accuracy for predicting the solar radiation in both validating stations.The AD-RF model was the best predictive,followed by AD-RS and AD-LWLR.Hence,this study recommends new effective methods to predict GSR in semiarid regions.展开更多
Building Information Modelling (BIM) is a methodology focused on the centralization and sharing of the project information among all professionals involved, supported on the generation and manipulation of a three-dime...Building Information Modelling (BIM) is a methodology focused on the centralization and sharing of the project information among all professionals involved, supported on the generation and manipulation of a three-dimensional (3D) digital BIM model. This methodology allows a close collaboration between the architect and the structural engineer and an adequate manipulation of the structural BIM model database, on the definition of multitasks. The collaboration allowed between all disciplines, avoid the detection of conflicts and data omission after in the construction place. Two BIM structural design cases were developed, using Revit as the modelling system and Robot as the structural software. Concerning the structural project the interoperability capacity between the software is still a limitation that engineers must be warned of. In the present study, the benefits and limitations identified within the communication and integration of distinct disciplines and on the development of most frequent multitasks normally related with a structural project, were considered.展开更多
The Building Information Modelling (BIM) methodology has been adopted in the construction industry, supporting the development of projects. Its implementation has improved the collaboration and integration in the desi...The Building Information Modelling (BIM) methodology has been adopted in the construction industry, supporting the development of projects. Its implementation has improved the collaboration and integration in the design context, increasing the accuracy of the project preparation and the decreasing additional costs and delays of the construction work. The main objective of the present research is to provide an overview of the state of the art of BIM applications, namely, concerning the construction planning. For that, the generation of a BIM 3D model, involving the disciplines of architecture, structures and water supply system was performed. After, over the model a conflict analysis was applied, in order to verify the consistency of all the disciplines, when linked together. In order to obtain a visual simulation of the construction process, the correspondent 4D BIM model was also generated. Along the development of the study, distinct BIM software was applied over a case study. The main remarks of the capacities of the software, as well as the benefits and limitations verified were identified.展开更多
This study proposes a concept for the development of a fireproof design code for the verification of dwellings susceptible to wildfire action.There are currently structural codes for the design of buildings when subje...This study proposes a concept for the development of a fireproof design code for the verification of dwellings susceptible to wildfire action.There are currently structural codes for the design of buildings when subjected to indoor fires,outside fires that grow on the facade of buildings,and even fires in an accident situation due to ignitions with hydrocarbons or transportation vehicles.All of these security verification specifications are described in EC1:1-2.The current regulation in Portugal uses safety criteria and risk categories that are for indoor fires,therefore is very conservative and may not present an economic fireproof design against the action of wildfires.The aim of this work is a straight verification based on natural temperature characteristic curves that simulate wildfire heat flow by convection,radiation,and the deposits of firebrands.展开更多
Increasing global energy consumption has become an urgent problem as natural energy sources such as oil,gas,and uranium are rapidly running out.Research into renewable energy sources such as solar energy is being purs...Increasing global energy consumption has become an urgent problem as natural energy sources such as oil,gas,and uranium are rapidly running out.Research into renewable energy sources such as solar energy is being pursued to counter this.Solar energy is one of the most promising renewable energy sources,as it has the potential to meet the world’s energy needs indefinitely.This study aims to develop and evaluate artificial intelligence(AI)models for predicting hourly global irradiation.The hyperparameters were optimized using the Broyden-FletcherGoldfarb-Shanno(BFGS)quasi-Newton training algorithm and STATISTICA software.Data from two stations in Algeria with different climatic zones were used to develop the model.Various error measurements were used to determine the accuracy of the prediction models,including the correlation coefficient,the mean absolute error,and the root mean square error(RMSE).The optimal support vector machine(SVM)model showed exceptional efficiency during the training phase,with a high correlation coefficient(R=0.99)and a low mean absolute error(MAE=26.5741 Wh/m^(2)),as well as an RMSE of 38.7045 Wh/m^(2) across all phases.Overall,this study highlights the importance of accurate prediction models in the renewable energy,which can contribute to better energy management and planning.展开更多
基金FCT I.P,for the funding through CALCITE Project(ref.PTDC/ECI-EGC/1086/2021).
文摘This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement technique,which is used in Civil Engineering applications to produce calcium carbonate through bacterial or enzymatic activity,replacing the use of other binder materials such as cement or resins,and therefore reducing carbon footprint.The microdevice was used to measure urease activity in the soil interstitial fluid,to investigate if bacterial activity could be affected by the presence of the particles and tortuosity from pore geometry.Such analysis is important to understand biocementation mechanism inside the soil and helps to improve the design of such treatment solutions.The device is basically a squared reservoir printed in polypropylene using a 3D printing machine,incorporating stainless steel electrodes in its base.The electrical resistivity was computed adopting Wenner method,by connecting 4 PCB electrodes to a signal generator and an oscilloscope for measuring the voltage when a AC current of 1 mA was applied.Both square and sinusoidal waves with 5 kHz frequency were selected among other frequencies.The measurements were adjusted during the calibration of the microdevice,done using standard salt solutions with known electrical conductivity measured using an electrical conductivity probe.For the bacterial activity measurements,the bacterial and urea solutions were added to a uniform-graded size quarzitic sand(average diameter 0.3 mm)placed inside the microdevice and covering completely the electrodes.Bacterial activity was not affected by the presence of the sand,which confirms that this treatment is effective for this type of soils.
基金supported by China Huaneng Group science and technology projects(No.HNKJ21-HF310,and HNKJ22-H10)China Huaneng Group science and technology project(Research and Application of Thermal Energy Evaluation and Gas Coupling Technology in Fengdong Huaneng Heating Zone,TY-21-HJK09)China Huaneng Group High-Level Talents Programme(Research on Spatial Distribution and Control Technology of Methane in Yunnan Diandong Mining Area).
文摘China is rich in geothermal resources,especially in Fujian Province,where 207 exposed hot springs have been discovered.The maximum temperature recorded in geothermal wells is above 121℃ in this province,indicating a high geothermal resource potential.However,large-scale breakthroughs in geothermal exploration are hindered by a lack of clear geothermal genetic models.In this study,the genetic model of a faultcontrolled mediumelow-temperature convection geothermal zone in the Fujian coastal area was determined by considering the tectonic characteristics of the area and the hydrochemical characteristics of the geothermal fluid(recharge,runoff and discharge characteristics,geothermal reservoir temperature,geothermal fluid circulation depth and renewability).The results showed that the exposed hot springs and high-temperature geothermal boreholes were concentrated in the Fu'aneNanjing and ChangleeZhao'an fault zones.At the intersection or faultbend of these two fault zones,there was strong stress release and activity,as demonstrated in the exposed parts of the high-temperature geothermal resources.The ChangleeZhao'an fault zone had a greater circulation depth,with an average heat storage temperature of 140℃,reflecting high geothermal resource potential.Considering the current temperature of the hot springs,Xiamen Bay and NanjingeJiulong River were identified as the next geothermal development zones.
文摘This paper summarizes the development of hydro-projects in China,blended with an international perspective.It expounds major technical progress toward ensuring the safe construction of high dams and river harnessing,and covers the theorization of uneven non-equilibrium sediment transport,inter-basin water diversion,giant hydro-generator units,pumped storage power stations,underground caverns,ecological protection,and so on.
基金supported by a PhD scholarship granted by Fundacao para a Ciencia e a Tecnologia,I.P.(FCT),Portugal,under the PhD Programme FLUVIO–River Restoration and Management,grant number:PD/BD/114558/2016。
文摘Floods are one of nature's most destructive disasters because of the immense damage to land,buildings,and human fatalities.It is difficult to forecast the areas that are vulnerable to flash flooding due to the dynamic and complex nature of the flash floods.Therefore,earlier identification of flash flood susceptible sites can be performed using advanced machine learning models for managing flood disasters.In this study,we applied and assessed two new hybrid ensemble models,namely Dagging and Random Subspace(RS)coupled with Artificial Neural Network(ANN),Random Forest(RF),and Support Vector Machine(SVM)which are the other three state-of-the-art machine learning models for modelling flood susceptibility maps at the Teesta River basin,the northern region of Bangladesh.The application of these models includes twelve flood influencing factors with 413 current and former flooding points,which were transferred in a GIS environment.The information gain ratio,the multicollinearity diagnostics tests were employed to determine the association between the occurrences and flood influential factors.For the validation and the comparison of these models,for the ability to predict the statistical appraisal measures such as Freidman,Wilcoxon signed-rank,and t-paired tests and Receiver Operating Characteristic Curve(ROC)were employed.The value of the Area Under the Curve(AUC)of ROC was above 0.80 for all models.For flood susceptibility modelling,the Dagging model performs superior,followed by RF,the ANN,the SVM,and the RS,then the several benchmark models.The approach and solution-oriented outcomes outlined in this paper will assist state and local authorities as well as policy makers in reducing flood-related threats and will also assist in the implementation of effective mitigation strategies to mitigate future damage.
文摘Based on systematic experiments on the influence of air entrainment on rock block stability in plunge pools impacted by high-velocity jets,this study presents adaptations of a physically based scour model.The modifications regarding jet aeration are implemented in the Comprehensive Scour Model(CSM),allowing it to reproduce the physical-mechanical processes involved in scour formation concerning the three phases;namely,water,rock,and air.The enhanced method considers the reduction of momentum of an aerated jet as well as the decrease of energy dissipation in the jet diffusive shear layer,both resulting from the entrainment of air bubbles.Block ejection from the rock mass depends on a combination of the aerated time-averaged pressure coefficient and the modified maximum dynamic impulsion coefficient,which was found to be a constant value of 0.2 for high-velocity jets in deep pools.The modified model is applied to the case of the observed scour hole at the Kariba Dam,with good agreement.
基金funded by the China Geological Survey (No. 1212011220731)
文摘The Weiquan Ag-polymetallic deposit is located on the southern margin of the Central Asian Orogenic Belt and in the western segment of the Aqishan-Yamansu arc belt in East Tianshan,northwestern China. Its orebodies, controlled by faults, occur in the lower Carboniferous volcanosedimentary rocks of the Yamansu Formation as irregular veins and lenses. Four stages of mineralization have been recognized on the basis of mineral assemblages, ore fabrics, and crosscutting relationships among the ore veins. Stage I is the skarn stage(garnet + pyroxene), Stage Ⅱ is the retrograde alteration stage(epidote + chlorite + magnetite ± hematite 士 actinolite ± quartz),Stage Ⅲ is the sulfide stage(Ag and Bi minerals + pyrite + chalcopyrite + galena + sphalerite + quartz ± calcite ± tetrahedrite),and Stage IV is the carbonate stage(quartz + calcite ± pyrite). Skarnization,silicification, carbonatization,epidotization,chloritization, sericitization, and actinolitization are the principal types of hydrothermal alteration. LAICP-MS U-Pb dating yielded ages of 326.5±4.5 and 298.5±1.5 Ma for zircons from the tuff and diorite porphyry, respectively. Given that the tuff is wall rock and that the orebodies are cut by a late diorite porphyry dike, the ages of the tuff and the diorite porphyry provide lower and upper time limits on the age of ore formation. The δ13C values of the calcite samples range from-2.5‰ to 2.3‰, the δ18OH2 Oand δDVSMOWvalues of the sulfide stage(Stage Ⅲ) vary from 1.1‰ to 5.2‰ and-111.7‰ to-66.1‰, respectively,and the δ13C, δ18OH2 Oand δDV-SMOWvalues of calcite in one Stage IV sample are 1.5‰,-0.3‰, and-115.6‰, respectively. Carbon, hydrogen, and oxygen isotopic compositions indicate that the ore-forming fluids evolved gradually from magmatic to meteoric sources. The δ34SV-CDTvalues of the sulfides have a large range from-6.9‰ to 1.4‰, with an average of-2.2‰, indicating a magmatic source, possibly with sedimentary contributions. The206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb ratios of the sulfides are 17.9848-18.2785,15.5188-15.6536, and 37.8125-38.4650, respectively, and one whole-rock sample at Weiquan yields206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb ratios of 18.2060, 15.5674, and 38.0511,respectively. Lead isotopic systems suggest that the ore-forming materials of the Weiquan deposit were derived from a mixed source involving mantle and crustal components. Based on geological features, zircon U-Pb dating, and C-H-OS-Pb isotopic data, it can be concluded that the Weiquan polymetallic deposit is a skarn type that formed in a tectonic setting spanning a period from subduction to post-collision. The ore materials were sourced from magmatic ore-forming fluids that mixed with components derived from host rocks during their ascent, and a gradual mixing with meteoric water took place in the later stages.
基金supported by Fundacao para a Ciencia e Tecnologia,PhD grant no.SFRH/BD/137531/2018,ongoing at Lisbon University,Instituto Superior Tecnico,Civil Engineering Research and Innovation for Sustainability(CERIS)Lopes and Reis are grateful for the Foundation for Science and Technology’s support through funding UIDB/04625/2020 from the research unit CERIS+1 种基金finantial support by FEDER-Fundo Europeu de Desenvolvimento Regional,through COMPETE 2020-Programa Operacional Fatores de Competitividadethe National Funds through FCT-Fundacao para a Ciencia e Tecnologia,projects no.UID/FIS/04650/2019 and no.POCI-01-0145-FEDER-028118.
文摘The spatial distribution of the world population is uneven,with a density of about 40%living in coastal regions.The trend is expected to continue in both demographic indicators and urban development rate,being many coastal cities in seismic-and tsunami-prone regions and built through informal and unplanned settlements,exposing their population and assets to such hazards.Recent tectonic-triggered events raised awareness of the cascading earthquake and tsunami threat and highlighted the paucity of structural design criteria considering the cumulative effects of both.By being exposed to the ground-motion,the structures’resistance may decrease and become residual/non-existent to support the incoming tsunami,implying an underestimation of the risk.Risk management can benefit from reinforcing the ties between natural hazards and engineering practitioners,linking science and industry,and promoting dialogue between risk analysts and policy-makers.Motivated by the expansion plans of an internationally-sized deep-water port located in a tsunami-prone region,a reflection on the work needed to perform a multi-risk assessment and the challenges yet to overcome is introduced to emphasize the challenge of combining safety requirements with financial and ecologic concerns.A conceptual interdisciplinarybased methodology is proposed to support uncertainty-aware,systematic and informed decisions.
文摘Temporally fine-grained and objective measures of mental states or their surrogate states are desperately needed in clinical psychiatry. Stress, both acute and especially chronic stress, is an important mental and physiological state observed in many mental disorders. It is a potential precipitant of acute psychiatric decompensations, be they anxious, affective, psychotic, or behavioural. Thus, being able to objectively follow stress or its surrogate parameters over time in a clinician-friendly way would help predict and prevent decompensations and monitor subsequent treatment success. Thus, we introduce the Compound Spectral Stress Indices (CSSI) that are derived from sensing data of various physiological and physiological and behavioural parameters we use as surrogate stress measures. To obtain the CSSI we use a hierarchical approach provided by adaptability, congruency and derived stress coefficient matrices. Adaptability is defined as a macroscopic characterisation of physiological and physiological and behavioural performance constructed as a product of the total variation of time-segmented complexity indices multiplied by the frequency of the time-varying distribution of complexity indices of the measured physiological or physiological and behavioural parameters, where complexity is expressed in terms of the Hurst exponent. Congruency is expressed by a constant characterising a demand-resource balance and it is then expressed in the form of a stress coefficient matrix. The CSSI is given by the spectral distance of the stress coefficient matrices from the ideal demand-resource matrix.
基金supported by National Natural Science Foundation of China(No.52270114)。
文摘Aiming at mercury and dioxin in fire coal gas as research objects,nonthermal plasma(NTP)catalytic technology was used to investigate the degradation effect of operating condition parameters on mixed pollutants in mixed flue gas condition,and to explore the synergistic degradation of Hg0and TCB(1,2,3-trichlorobenzene,TCB)under mixed flue gas conditions.The research results showed that the conversion efficiency of mercury and TCB increased with the additional output of voltage,and decreased with the increase of the gas flow rate.Under optimal reaction conditions:voltage=17 k V,frequency=300 Hz,gas flow rate=21 min^(-1),the conversion efficiency of Hg^(0)and TCB reached the highest 91.4%and 84.98%,respectively.In the NTP catalytic system,active free radicals played an important role in the synergistic conversion of mercury and TCB,which have a competitive effect,to make the conversion efficiency of mixed pollutants lower than a single substance.In the mixed flue gas condition,the mixed gas has an inhibitory effect on the synergistic conversion of mercury and TCB.Kinetic modeling of NTP catalytic synergistic reaction was established.Under three conditions of TCB,mercury and TCB,mixed simulated flue gas,the NTP catalytic technology showed a quasi-firstorder kinetic reaction for the degradation of TCB.According to the synergistic effect of NTP and composites,the transformation and degradation of TCB mainly included two processes:TCB and ring opening,and Hg^(0)was finally oxidized to Hg^(2+).
文摘This paper describes the experimental procedure followed to fabricate and validate sol-gel based RH sensors which will be incorporated in soil specimens for standard laboratorial tests. It is the first time such sensors were used for soil suction measurement. They are microfabricated relative humidity sensors (footprint area 11,000 μm × 22,000 μm) operating based on changes in electrical resistivity detected by a cerium doped silica titania film deposited using a sol-gel technique. Their design required gathering experts in several engineering specialties. The working principle of the sensors is based on water vapour equilibrium between the air in the soil and in the sol-gel pores, due to the contact between the two porous materials. The spacing between interdigitated aluminium electrodes was optimized to improve the sensing properties of the sol-gel. The calibration of the different prototypes was done against compacted clay, varying the spacing between 100 and 700 μm. The sensors were also incorporated in soil samples for suction measurement during wetting and drying paths. They were validated by comparing the readings with those from a water dew point potentiometer. From this study it was possible to determine the optimum electrodes spacing of 200 μm. Error was explained by sol-gel heterogeneity effect and by the resolution of the sensing area provided by the electrodes spacing. When comparing with other sensors operating inside soil specimens in standard laboratorial tests, these sol-gel sensors extend the operation range available with the alternative technologies: while conventional tensiometers measure suction ranges from 0 to 1.8 MPa, our sensors demonstrate good results between 1 to 10 MPa (and higher).
文摘We study the congestion phenomenon in a mathematical model of the data packets traffic in transmission networks as a function of the topology and of the load of the network. Two types of traffic are considered: homogeneous and heterogeneous traffic. The congestion phenomenon is studied in stationary conditions through the behaviour of two quantities: the mean travel time of a packet and the mean number of packets that have not reached their destination and are traveling in the network. We define a transformation that maps a network having the small world property (Inet 3037 in our numerical experiments) into a (modified) lattice network that has the same number of nodes. This map changes the capacity of the branches of the graphs representing the networks and can be regarded as an “interpolation” between the two classes of networks. Using this transformation we compare the behaviour of Inet 3037 to the behaviour of a modified rectangular lattice and we study the behaviour of the interpolating networks. This study suggests how to change the network topology and the branch capacities in order to alleviate the congestion phenomenon. In the website: http://www.ceri.uniroma1.it/ceri/zirilli/w6 some auxiliary material including animations and stereo?graphic scenes that helps the understanding of this paper is shown.
文摘Earth construction,including the use of earth mortars,has been extensively used in the past.However,with the appearance of hydraulic binders,the use of earth strongly decreased for new construction and even to repair old earth buildings,whose best solution would be the use of compatible materials such as earth mortars.Due to the innumerable advantages of earth and with the growing concern on eco-efficient construction,the interest on earth construction has resurfaced,namely on earth mortars.To optimize the composition of an earth plastering mortar made with a defined clayish earth and two siliceous sands with different particle sizes,six compositions were assessed.Mortars with different volumetric ratios were applied in two different supports(on the back of a tile and on a brick)and planar specimens were also produced.Distinct characteristics were assessed,such as their visual appearance,shrinkage,surface cohesion,surface hardness,dry abrasion resistance,ultrasonic velocity,adhesive strength,and thermal conductivity.It is possible to conclude that a higher clay content in the earth mortar composition increases the shrinkage and occurrence of cracking,the use of fine sand promotes high mass loss by abrasion,and the same mortar applied in different supports behaves differently in terms of durability.
基金supported by the Portuguese Foundation for Science and Technology(FCT)through the project PTDC/CTA-OHR/30561/2017(WinTherface).
文摘Solar energy represents one of themost important renewable energy sources contributing to the energy transition process.Considering that the observation of daily global solar radiation(GSR)is not affordable in some parts of the globe,there is an imperative need to develop alternative ways to predict it.Therefore,the main objective of this study is to evaluate the performance of different hybrid data-driven techniques in predicting daily GSR in semi-arid regions,such as the majority of Spanish territory.Here,four ensemble-based hybrid models were developed by hybridizing Additive Regression(AR)with Random Forest(RF),Locally Weighted Linear Regression(LWLR),Random Subspace(RS),and M5P.The base algorithms of the developed models are scarcely applied in previous studies to predict solar radiation.The testing phase outcomes demonstrated that the ARRF models outperform all other hybrid models.The provided models were validated by statisticalmetrics,such as the correlation coefficient(R)and root mean square error(RMSE).The results proved that Scenario#6,utilizing extraterrestrial solar radiation,relative humidity,wind speed,and mean,maximum,and minimum ambient air temperatures as the model inputs,leads to the most accurate predictions among all scenarios(R=0.968–0.988 and RMSE=1.274–1.403 MJ/m^(2)・d).Also,Scenario#3 stood in the next rank of accuracy for predicting the solar radiation in both validating stations.The AD-RF model was the best predictive,followed by AD-RS and AD-LWLR.Hence,this study recommends new effective methods to predict GSR in semiarid regions.
文摘Building Information Modelling (BIM) is a methodology focused on the centralization and sharing of the project information among all professionals involved, supported on the generation and manipulation of a three-dimensional (3D) digital BIM model. This methodology allows a close collaboration between the architect and the structural engineer and an adequate manipulation of the structural BIM model database, on the definition of multitasks. The collaboration allowed between all disciplines, avoid the detection of conflicts and data omission after in the construction place. Two BIM structural design cases were developed, using Revit as the modelling system and Robot as the structural software. Concerning the structural project the interoperability capacity between the software is still a limitation that engineers must be warned of. In the present study, the benefits and limitations identified within the communication and integration of distinct disciplines and on the development of most frequent multitasks normally related with a structural project, were considered.
文摘The Building Information Modelling (BIM) methodology has been adopted in the construction industry, supporting the development of projects. Its implementation has improved the collaboration and integration in the design context, increasing the accuracy of the project preparation and the decreasing additional costs and delays of the construction work. The main objective of the present research is to provide an overview of the state of the art of BIM applications, namely, concerning the construction planning. For that, the generation of a BIM 3D model, involving the disciplines of architecture, structures and water supply system was performed. After, over the model a conflict analysis was applied, in order to verify the consistency of all the disciplines, when linked together. In order to obtain a visual simulation of the construction process, the correspondent 4D BIM model was also generated. Along the development of the study, distinct BIM software was applied over a case study. The main remarks of the capacities of the software, as well as the benefits and limitations verified were identified.
文摘This study proposes a concept for the development of a fireproof design code for the verification of dwellings susceptible to wildfire action.There are currently structural codes for the design of buildings when subjected to indoor fires,outside fires that grow on the facade of buildings,and even fires in an accident situation due to ignitions with hydrocarbons or transportation vehicles.All of these security verification specifications are described in EC1:1-2.The current regulation in Portugal uses safety criteria and risk categories that are for indoor fires,therefore is very conservative and may not present an economic fireproof design against the action of wildfires.The aim of this work is a straight verification based on natural temperature characteristic curves that simulate wildfire heat flow by convection,radiation,and the deposits of firebrands.
文摘Increasing global energy consumption has become an urgent problem as natural energy sources such as oil,gas,and uranium are rapidly running out.Research into renewable energy sources such as solar energy is being pursued to counter this.Solar energy is one of the most promising renewable energy sources,as it has the potential to meet the world’s energy needs indefinitely.This study aims to develop and evaluate artificial intelligence(AI)models for predicting hourly global irradiation.The hyperparameters were optimized using the Broyden-FletcherGoldfarb-Shanno(BFGS)quasi-Newton training algorithm and STATISTICA software.Data from two stations in Algeria with different climatic zones were used to develop the model.Various error measurements were used to determine the accuracy of the prediction models,including the correlation coefficient,the mean absolute error,and the root mean square error(RMSE).The optimal support vector machine(SVM)model showed exceptional efficiency during the training phase,with a high correlation coefficient(R=0.99)and a low mean absolute error(MAE=26.5741 Wh/m^(2)),as well as an RMSE of 38.7045 Wh/m^(2) across all phases.Overall,this study highlights the importance of accurate prediction models in the renewable energy,which can contribute to better energy management and planning.
