Most downloaded articles
2020, 42(1):168-179.
DOI: 10.11835/j.issn.2096-6717.2019.158
Abstract:
Rapid urbanization and global warming aggravate the thermal discomfort of urban outdoor environment and increase the risk of thermal security. In order to find out the physiological parameters changes of human body in outdoor thermal environment, provide a basis for rapid urban thermal environment evaluation, an outdoor experiment was carried out to observe the thermal response of human body. Based on the measured data, the simulation precision analysis and coincidence test of the two-node model were carried out. It is found that human skin temperature and body core temperature show different trends under the influence of outdoor wind speed, MRT and self-regulation, in order to ensure the simulation accuracy, the two-node model of human body needs to be modified from the following four aspects:skin and core temperature, standard human model, temperature of regulation starting, convective heat transfer coefficient, relevant parameters and calculation process shall be written as assignable variables or mathematical expressions, the revised two-node model is universal and applicable to the prediction of outdoor human thermal response.
Rapid urbanization and global warming aggravate the thermal discomfort of urban outdoor environment and increase the risk of thermal security. In order to find out the physiological parameters changes of human body in outdoor thermal environment, provide a basis for rapid urban thermal environment evaluation, an outdoor experiment was carried out to observe the thermal response of human body. Based on the measured data, the simulation precision analysis and coincidence test of the two-node model were carried out. It is found that human skin temperature and body core temperature show different trends under the influence of outdoor wind speed, MRT and self-regulation, in order to ensure the simulation accuracy, the two-node model of human body needs to be modified from the following four aspects:skin and core temperature, standard human model, temperature of regulation starting, convective heat transfer coefficient, relevant parameters and calculation process shall be written as assignable variables or mathematical expressions, the revised two-node model is universal and applicable to the prediction of outdoor human thermal response.
2012, 34(2):69-76.
DOI: 10.11835/j.issn.1674-4764.2012.02.012
Abstract:
Seven specimens were loaded with axial force and horizontal cycle force to analyze the hysteretic performance and the influencing factor as well. The influence of axial compression ratio and aspect ratio on the hysteretic performance was investigated, including the buckling behaviors and the energy dissipation. And the positive role of combined effects on the hysteretic performance of cold-formed specimens was studied emphatically. The experiment reveals that a large axial compression ratio incurs a serious decrease on hysteretic performance, while the combined effects give an increase on it. In addition, the numerical mode is set up. Considering double nonlinearity, the results of experiment and simulation match each other well. Based on the data, it is obtained that local buckling plays a great negative role during the loading course. At last, the characteristics of hysteretic performance of cold-formed steel specimens are concluded and some suggestions are given.
Seven specimens were loaded with axial force and horizontal cycle force to analyze the hysteretic performance and the influencing factor as well. The influence of axial compression ratio and aspect ratio on the hysteretic performance was investigated, including the buckling behaviors and the energy dissipation. And the positive role of combined effects on the hysteretic performance of cold-formed specimens was studied emphatically. The experiment reveals that a large axial compression ratio incurs a serious decrease on hysteretic performance, while the combined effects give an increase on it. In addition, the numerical mode is set up. Considering double nonlinearity, the results of experiment and simulation match each other well. Based on the data, it is obtained that local buckling plays a great negative role during the loading course. At last, the characteristics of hysteretic performance of cold-formed steel specimens are concluded and some suggestions are given.
2022, 44(3):104-118.
DOI: 10.11835/j.issn.2096-6717.2021.160
Abstract:
Electro-oxidation technology, as one common seen electrochemical water treatment technology, can effectively address the problems in which conventional water purification technology cannot or cannot easily solve.It has becoming a promising strategy for its extraordinary features and advantages, especially in ultra-low discharge requirements of water treatment. The development of electro-oxidation technology enriches green catalytic oxidation system and is of great scientific significance for constructing "carbon neutral" water treatment technology. In the past ten years, electro-oxidation technology has drawn increasing attention and achieved great progresses.In aiming of aqueous pollutants removal, resource and energy recovery from wastewater, numerous studies focused on the design and modification of functional electrode materials, as well as exploiting efficient reactors. In this review, the mechanism and research progresses of electro-oxidation water treatment technology were systematically discussed. A conclusion on its future development was summarized.
Electro-oxidation technology, as one common seen electrochemical water treatment technology, can effectively address the problems in which conventional water purification technology cannot or cannot easily solve.It has becoming a promising strategy for its extraordinary features and advantages, especially in ultra-low discharge requirements of water treatment. The development of electro-oxidation technology enriches green catalytic oxidation system and is of great scientific significance for constructing "carbon neutral" water treatment technology. In the past ten years, electro-oxidation technology has drawn increasing attention and achieved great progresses.In aiming of aqueous pollutants removal, resource and energy recovery from wastewater, numerous studies focused on the design and modification of functional electrode materials, as well as exploiting efficient reactors. In this review, the mechanism and research progresses of electro-oxidation water treatment technology were systematically discussed. A conclusion on its future development was summarized.
2022, 44(3):86-103.
DOI: 10.11835/j.issn.2096-6717.2021.155
Abstract:
The development of membrane-based wastewater treatment technology faces two challenges, i.e.:(i) improvement in the environment quality requires high-standard treatment, and (ii) carbon emission peak and carbon neutrality calls for green and sustainable techniques. Under such circumstances, methods to break the bottleneck of water permeability and pollutant removal efficiency trade-off, to reduce the energy consumption and carbon emission of membrane technology, and to stimulate the sustainable development of membrane-based wastewater treatment are of great significance.Recently, remarkable progress in membrane-based wastewater treatment has been achieved in terms of membrane separation fundamentals, antifouling membrane preparation, membrane process innovations, and engineering applications. Current efforts have been dedicated to precise design of membrane materials, functionalization of membrane interface, and process greening transformation. In this work, recent research progress has been reviewed in terms of functional extension of membrane technology/process, design of high-performance membrane materials, sustainable utilization of membranes, and green development of membrane processes. Further analysis and discussion on future development are also presented.In the context of future multi-target needs, multi-functionalization, selective and customized separation, and green development are worthy of in-depth research for promoting the sustainable evolution of membrane-based wastewater treatment technology.
The development of membrane-based wastewater treatment technology faces two challenges, i.e.:(i) improvement in the environment quality requires high-standard treatment, and (ii) carbon emission peak and carbon neutrality calls for green and sustainable techniques. Under such circumstances, methods to break the bottleneck of water permeability and pollutant removal efficiency trade-off, to reduce the energy consumption and carbon emission of membrane technology, and to stimulate the sustainable development of membrane-based wastewater treatment are of great significance.Recently, remarkable progress in membrane-based wastewater treatment has been achieved in terms of membrane separation fundamentals, antifouling membrane preparation, membrane process innovations, and engineering applications. Current efforts have been dedicated to precise design of membrane materials, functionalization of membrane interface, and process greening transformation. In this work, recent research progress has been reviewed in terms of functional extension of membrane technology/process, design of high-performance membrane materials, sustainable utilization of membranes, and green development of membrane processes. Further analysis and discussion on future development are also presented.In the context of future multi-target needs, multi-functionalization, selective and customized separation, and green development are worthy of in-depth research for promoting the sustainable evolution of membrane-based wastewater treatment technology.
2024, 46(1):14-32.
DOI: 10.11835/j.issn.2096-6717.2022.016
Abstract:
Artificial intelligence is the core driver of the next generation of industrial change. It is an important method to comprehensively improve digitalization, automation, informatization, and intelligence in the field of civil engineering. To gain a comprehensive understanding of the development and application of artificial intelligence in civil engineering. The basic research areas of artificial intelligence are analyzed qualitatively. The current research status of artificial intelligence in civil engineering design, manufacturing, and maintenance phases is quantitatively analyzed. The CiteSpace visualization tool is used to dig deeper into the problems, development bottlenecks, and research trends of artificial intelligence in civil engineering, and give corresponding solutions and research ideas. The review of the literature found that a significant amount of artificial intelligence research has been conducted in the field of civil engineering. However the development of intelligence has been uneven at various stages, and there are limitations in practical applications. Therefore, it is necessary to deeply explore the cross-integration of intelligent technologies such as neural networks, big data, and deep learning in the full life cycle of civil engineering. To promote the synergistic development of artificial intelligence research in the field of civil engineering.
Artificial intelligence is the core driver of the next generation of industrial change. It is an important method to comprehensively improve digitalization, automation, informatization, and intelligence in the field of civil engineering. To gain a comprehensive understanding of the development and application of artificial intelligence in civil engineering. The basic research areas of artificial intelligence are analyzed qualitatively. The current research status of artificial intelligence in civil engineering design, manufacturing, and maintenance phases is quantitatively analyzed. The CiteSpace visualization tool is used to dig deeper into the problems, development bottlenecks, and research trends of artificial intelligence in civil engineering, and give corresponding solutions and research ideas. The review of the literature found that a significant amount of artificial intelligence research has been conducted in the field of civil engineering. However the development of intelligence has been uneven at various stages, and there are limitations in practical applications. Therefore, it is necessary to deeply explore the cross-integration of intelligent technologies such as neural networks, big data, and deep learning in the full life cycle of civil engineering. To promote the synergistic development of artificial intelligence research in the field of civil engineering.
6 Influence factors of normal bonding properties between mortar and mechanical pressing raw-soil brick
2018, 40(1):78-82.
DOI: 10.11835/j.issn.1674-4764.2018.01.011
Abstract:
In order to investigate the influence factors of normal bonding properties between mortar and mechanical pressing raw-soil brick, the tensile bond strength test was made between mortar and mechanical pressing raw-soil brick with different interfacial condition.There were 72 specimens in total and three ages including 7d, 14d and 28d.The failure mode and the change rules of normal adhesive strength in different ages between raw-soil brick and mortar were explored. The influence of interfacial condition and ages on normal adhesive strength and failure mode was studied. The results show that interfacial condition and ages both have an influence on normal adhesive strength, which is improved along with ages and is decreased because of roughing. The normal bonding properties between mortar and mechanical pressing raw-soil brick is impacted by the type of mortar evidently. The reference for engineering application of raw soil mechanism brick is provided by the research results.
In order to investigate the influence factors of normal bonding properties between mortar and mechanical pressing raw-soil brick, the tensile bond strength test was made between mortar and mechanical pressing raw-soil brick with different interfacial condition.There were 72 specimens in total and three ages including 7d, 14d and 28d.The failure mode and the change rules of normal adhesive strength in different ages between raw-soil brick and mortar were explored. The influence of interfacial condition and ages on normal adhesive strength and failure mode was studied. The results show that interfacial condition and ages both have an influence on normal adhesive strength, which is improved along with ages and is decreased because of roughing. The normal bonding properties between mortar and mechanical pressing raw-soil brick is impacted by the type of mortar evidently. The reference for engineering application of raw soil mechanism brick is provided by the research results.
2012, 34(Z1):116-119.
Abstract:
For multilayer concrete structure, the seismic ability of the ground floor column is very poor, improving the seismic fortification intensity of structure is adopted in this paper, the axial force, shear and moment of beam and column are calculated and analyzed in seven degree and eight degree seismic fortification intensity. Numerical results show that with improving the fortification intensity of the structure, the axial force, shear and moment of beam and column increase and the change of the ground floor is the most prominent. In earthquake the destruction of the structure mainly happens in the ground floor column, so this problem is solved fundamentally with increasing fortification intensity in architectural design.
For multilayer concrete structure, the seismic ability of the ground floor column is very poor, improving the seismic fortification intensity of structure is adopted in this paper, the axial force, shear and moment of beam and column are calculated and analyzed in seven degree and eight degree seismic fortification intensity. Numerical results show that with improving the fortification intensity of the structure, the axial force, shear and moment of beam and column increase and the change of the ground floor is the most prominent. In earthquake the destruction of the structure mainly happens in the ground floor column, so this problem is solved fundamentally with increasing fortification intensity in architectural design.
2021, 43(S1):268-279.
DOI: 10.11835/j.issn.2096-6717.2021.230
Abstract:
With the advent of digital era characterized by informatization and intelligence, the development and innovation of bridge engineering technology are promoted. It is necessary to integrate cloud computing, big data, artificial intelligence, 3D printing, robot and other strategic emerging industrial technologies with bridge engineering, and promote the industrialization, digitization and intelligent upgrading of bridges from multiple dimensions such as intelligent design, construction, operation and maintenance. This paper reviews related frontier technologies and important achievements worldwide in 2020, with regard to bridge informatization, intelligent inspection, safety operation and maintenance, intelligent disaster prevention/mitigation, intelligent materials, and summarizes the research hotspots and prospects. According to the review, BIM technologies can improve the refinement of bridge forward design, the accuracy of construction process control and management. Intelligent inspection technologies (e.g. UAV and robots)and artificial intelligence technologies (e.g. machine learning and convolution neural network)improve the accuracy and efficiency of bridge inspection and monitoring. Applications of high-performance intelligent materials promotes the self-perception, self-adaptability, self-adjustment and self-diagnosis of bridge. Natural disaster monitoring and early warning based on artificial intelligence (AI)provides new development idea for bridge intelligent disaster prevention. To conform to the development trend of informatization and intelligence, future research should deeply integrate artificial intelligence technology into the whole life cycle of bridge design, construction and maintenance to realize the dream of bridge power.
With the advent of digital era characterized by informatization and intelligence, the development and innovation of bridge engineering technology are promoted. It is necessary to integrate cloud computing, big data, artificial intelligence, 3D printing, robot and other strategic emerging industrial technologies with bridge engineering, and promote the industrialization, digitization and intelligent upgrading of bridges from multiple dimensions such as intelligent design, construction, operation and maintenance. This paper reviews related frontier technologies and important achievements worldwide in 2020, with regard to bridge informatization, intelligent inspection, safety operation and maintenance, intelligent disaster prevention/mitigation, intelligent materials, and summarizes the research hotspots and prospects. According to the review, BIM technologies can improve the refinement of bridge forward design, the accuracy of construction process control and management. Intelligent inspection technologies (e.g. UAV and robots)and artificial intelligence technologies (e.g. machine learning and convolution neural network)improve the accuracy and efficiency of bridge inspection and monitoring. Applications of high-performance intelligent materials promotes the self-perception, self-adaptability, self-adjustment and self-diagnosis of bridge. Natural disaster monitoring and early warning based on artificial intelligence (AI)provides new development idea for bridge intelligent disaster prevention. To conform to the development trend of informatization and intelligence, future research should deeply integrate artificial intelligence technology into the whole life cycle of bridge design, construction and maintenance to realize the dream of bridge power.
2021, 43(S1):175-184.
DOI: 10.11835/j.issn.2096-6717.2021.218
Abstract:
Ultra High Performance Concrete (UHPC)is combined with the Orthotropic Steel Deck (OSD)in a lot of projects nowadays. That is a typical example of the implementation of new materials and new structures in bridge engineering. Benefitting from its high stiffness, UHPC slab can evidently reduce the local deformation of OSD. In this way, we can greatly reduce the fatigue stress amplitude and the fatigue resistance is increased. In the present work, we reviewed the research advances on the composite UHPC-OSD system from five aspects: the new structures, the shear connectors, the basic static behaviors of the composite deck, the fatigue performance of the composite deck and the basic mechanical properties of UHPC or UHPC members. Most of the concerned literature was published in 2020 or 2021. However, some works reported in a few other recent years were still mentioned in the present work.
Ultra High Performance Concrete (UHPC)is combined with the Orthotropic Steel Deck (OSD)in a lot of projects nowadays. That is a typical example of the implementation of new materials and new structures in bridge engineering. Benefitting from its high stiffness, UHPC slab can evidently reduce the local deformation of OSD. In this way, we can greatly reduce the fatigue stress amplitude and the fatigue resistance is increased. In the present work, we reviewed the research advances on the composite UHPC-OSD system from five aspects: the new structures, the shear connectors, the basic static behaviors of the composite deck, the fatigue performance of the composite deck and the basic mechanical properties of UHPC or UHPC members. Most of the concerned literature was published in 2020 or 2021. However, some works reported in a few other recent years were still mentioned in the present work.
2021, 43(S1):288-296.
DOI: 10.11835/j.issn.2096-6717.2021.232
Abstract:
Prefabricated bridges have became an important development direction of bridge construction due to the advantages of good construction quality, low impact on the environment, short on-site operation time, and high level of construction safety. Prefabricated concrete bridges are not only suitable for urban road bridges with complex traffic, but also for railway bridges in difficult construction environments. This paper sorts out the research progress of prefabricated concrete bridges at home and abroad in 2020 through the method of literature analysis. According to the types of bridge structure, new technologies, new structures and typical engineering applications in this field are discussed from two aspects: the upper structure and the lower structure. After a rough summary in this article, in the superstructure, the connection structure, crack resistance and durability of the nodes have received extensive attention from scholars; in the substructure, as the prefabricated system is applied to the bridge in the high-intensity earthquake area, the structure and seismic performance of prefabricated bridge piers are currently hot research topics. The durability and crack resistance of the substructure still need to be improved.
Prefabricated bridges have became an important development direction of bridge construction due to the advantages of good construction quality, low impact on the environment, short on-site operation time, and high level of construction safety. Prefabricated concrete bridges are not only suitable for urban road bridges with complex traffic, but also for railway bridges in difficult construction environments. This paper sorts out the research progress of prefabricated concrete bridges at home and abroad in 2020 through the method of literature analysis. According to the types of bridge structure, new technologies, new structures and typical engineering applications in this field are discussed from two aspects: the upper structure and the lower structure. After a rough summary in this article, in the superstructure, the connection structure, crack resistance and durability of the nodes have received extensive attention from scholars; in the substructure, as the prefabricated system is applied to the bridge in the high-intensity earthquake area, the structure and seismic performance of prefabricated bridge piers are currently hot research topics. The durability and crack resistance of the substructure still need to be improved.
2021, 43(S1):242-251.
DOI: 10.11835/j.issn.2096-6717.2021.227
Abstract:
Bridge impact is a key problem for existing bridges and bridges under construction for a long time. The research on impact and protection problems meets the needs of development. In recent years, scholars have paid more and more attention to bridge impact, and conducted a lot of researches. Following the New Progress and Prospect of Bridge Impact Research in 2019, the author continues to summarize the progress in 2020 in three aspects, such as bridge ship collision, rockfall impact and vehicle collision bridge. Among them, for the bridge ship collision problem, the new code clearly proposes that the main structure of highway bridge should adopt the performance-based anti-collision design method. In 2020, sand mining vessel collision accidents, the broken of Yaxi high-speed bridge, and many vehicle bridge collision events have occurred. This paper sortes these bridge impact events, analyzes and summarizes the relevant achievements in the past year according to personal understanding, and then puts forward the problems that need to be further considered in the future research.
Bridge impact is a key problem for existing bridges and bridges under construction for a long time. The research on impact and protection problems meets the needs of development. In recent years, scholars have paid more and more attention to bridge impact, and conducted a lot of researches. Following the New Progress and Prospect of Bridge Impact Research in 2019, the author continues to summarize the progress in 2020 in three aspects, such as bridge ship collision, rockfall impact and vehicle collision bridge. Among them, for the bridge ship collision problem, the new code clearly proposes that the main structure of highway bridge should adopt the performance-based anti-collision design method. In 2020, sand mining vessel collision accidents, the broken of Yaxi high-speed bridge, and many vehicle bridge collision events have occurred. This paper sortes these bridge impact events, analyzes and summarizes the relevant achievements in the past year according to personal understanding, and then puts forward the problems that need to be further considered in the future research.
2011, 33(1):77-86.
DOI: 10.11835/j.issn.1674-4764.2011.01.014
Abstract:
Based on fuzzy self-adapting stochastic damage model, the characteristics of generalized damage stress field on material crack tip are studied. The results express that the numerical algorithm is reliable. Sensitivity of rolled-concrete gravity dam under fuzzy-stochastic damage gaining is implemented by considering the spatial variation of material parameters. It is found that the compression strength of rolled-concrete is the governing index on gravity dam reliability. The activation simulations on fuzzy self-adapting stochastic damage model were carried by adopting different fuzzy distributions, which indicated the governing characteristics of the distribution on generalized damage evolution of rock-like material.
Based on fuzzy self-adapting stochastic damage model, the characteristics of generalized damage stress field on material crack tip are studied. The results express that the numerical algorithm is reliable. Sensitivity of rolled-concrete gravity dam under fuzzy-stochastic damage gaining is implemented by considering the spatial variation of material parameters. It is found that the compression strength of rolled-concrete is the governing index on gravity dam reliability. The activation simulations on fuzzy self-adapting stochastic damage model were carried by adopting different fuzzy distributions, which indicated the governing characteristics of the distribution on generalized damage evolution of rock-like material.
13 Nonlinear behavior of pilesunder inclined and eccentric loads indouble layered soils by model test
2018, 40(1):68-77.
DOI: 10.11835/j.issn.1674-4764.2018.01.010
Abstract:
A new hyperbolic p-y curve was derived to generally simulate then onlinearity of piles in layered soils, and the new p-y curve was presented containing parameters such as the initial ratio of elastic foundation coefficient, the initial elastic foundation coefficient,characteristic value of lateral displacementfor soils, and etc.. Model test of six timber piles and two steel piles in two groups settled in layer soils with upper clay and lower sand were done. The calculated lateral displacements of model piles both at the top and at the ground are consistent with the test values by p-y curve method, and the new hyperbolic p-y curve is verified. While the characteristic value of lateral displacement for layered soils increases, the displacement and the maximum bending moment of the pile decrease, the maximum shear and the maximum soil pressure around the pile increase. The variety of characteristic value of lateral displacement for the lower sand has extremely small effect on mechanical property of the pile, then the characteristic value of lateral displacement for lower soils can be defined as the same as that of the top soil during engineering application.
A new hyperbolic p-y curve was derived to generally simulate then onlinearity of piles in layered soils, and the new p-y curve was presented containing parameters such as the initial ratio of elastic foundation coefficient, the initial elastic foundation coefficient,characteristic value of lateral displacementfor soils, and etc.. Model test of six timber piles and two steel piles in two groups settled in layer soils with upper clay and lower sand were done. The calculated lateral displacements of model piles both at the top and at the ground are consistent with the test values by p-y curve method, and the new hyperbolic p-y curve is verified. While the characteristic value of lateral displacement for layered soils increases, the displacement and the maximum bending moment of the pile decrease, the maximum shear and the maximum soil pressure around the pile increase. The variety of characteristic value of lateral displacement for the lower sand has extremely small effect on mechanical property of the pile, then the characteristic value of lateral displacement for lower soils can be defined as the same as that of the top soil during engineering application.
2021, 43(S1):91-99.
DOI: 10.11835/j.issn.2096-6717.2021.209
Abstract:
Earthquake may cause great damage to bridge structure, damage and even collapse of bridge. The seismic resistance of bridges has always been an important research direction in the field of bridges. This paper summarizes the research results and development trend of the seismic field of bridges in 2020, and the main conclusions are as follows: the seismic performance of the pier column after replacing ordinary concrete with new materials is explored; The shaking isolation pier has good seismic performance through shaking table experiment and numerical simulation; The displacement ductility and residual displacement of the pier can be improved by using the carbon fiber cloth sheath to strengthen the pier column; The traditional single leg to double limb thin-walled high pier has better seismic performance, the hysteretic curve of the double limb thin-walled pier with high main reinforcement ratio is full, and the energy consumption performance is good, and the axial pressure ratio is improved significantly; The rectangular hollow double column high pier with energy dissipation beam has better energy consumption capacity, bearing capacity and displacement ductility; The system of vibration reduction with friction pendulum support and limit energy dissipation rod has good effect of reducing isolation, and the internal force damping rate can reach more than 20%; The reliability of using new type of unbonded steel mesh rubber support (USRB) instead of unbonded laminated rubber support (ULNR) in bridge is studied; The influence of near field vibration and soil structure interaction on the dynamic response of the bridge is investigated.
Earthquake may cause great damage to bridge structure, damage and even collapse of bridge. The seismic resistance of bridges has always been an important research direction in the field of bridges. This paper summarizes the research results and development trend of the seismic field of bridges in 2020, and the main conclusions are as follows: the seismic performance of the pier column after replacing ordinary concrete with new materials is explored; The shaking isolation pier has good seismic performance through shaking table experiment and numerical simulation; The displacement ductility and residual displacement of the pier can be improved by using the carbon fiber cloth sheath to strengthen the pier column; The traditional single leg to double limb thin-walled high pier has better seismic performance, the hysteretic curve of the double limb thin-walled pier with high main reinforcement ratio is full, and the energy consumption performance is good, and the axial pressure ratio is improved significantly; The rectangular hollow double column high pier with energy dissipation beam has better energy consumption capacity, bearing capacity and displacement ductility; The system of vibration reduction with friction pendulum support and limit energy dissipation rod has good effect of reducing isolation, and the internal force damping rate can reach more than 20%; The reliability of using new type of unbonded steel mesh rubber support (USRB) instead of unbonded laminated rubber support (ULNR) in bridge is studied; The influence of near field vibration and soil structure interaction on the dynamic response of the bridge is investigated.
Wei Chaohai
,
Zhou Hongtao
,
Huang Jing
,
Wei Cong
,
Yang Xingzhou
,
Wei Jingyue
,
Li Zemin
,
Hu Yun
,
Ren Yuan
2019, 41(5):151-163.
DOI: 10.11835/j.issn.2096-6717.2019.106
Abstract:
Wastewater treatment is a complex process with high energy consumption and low efficiency. Different from the traditional concept of wastewater treatment, the pollutants contained of wastewater can be regarded as energy materials or as the raw materials of other products to be havested to reduce the energy consumption. The forms of the pollutants' embodied energy in wastewater were examined by employing two calculation methods and taking sewage and coking wastewater as examples. Moreover, two possible path ways for the utilization and maximization of the recovery of embodied energy during the wastewater treatment were discussed. The different forms of energy consumption and their causes in wastewater treatment process were analyzed based on thermodynamic laws and quality characteristics of the wastewater, with reasonable assumptions. The laws of energy transfer and distribution of two specific cases are expressed by the energy flow diagram. Some possible energy-saving approaches and wastewater treatment methods in the future are predicted by comparing different energy saving technologies. Based on in-depth understanding of the embodied energy in wastewaters, valuable elements such as nutrients (nitrogen, phosphorus) and heavy metals can be separated and recovered, and water resources can be reused by combining with related industries and technologies. Therefore, the goal of energy saving can be achieved by the indirect compensation of energy consumption in the wastewater treatment process.
Wastewater treatment is a complex process with high energy consumption and low efficiency. Different from the traditional concept of wastewater treatment, the pollutants contained of wastewater can be regarded as energy materials or as the raw materials of other products to be havested to reduce the energy consumption. The forms of the pollutants' embodied energy in wastewater were examined by employing two calculation methods and taking sewage and coking wastewater as examples. Moreover, two possible path ways for the utilization and maximization of the recovery of embodied energy during the wastewater treatment were discussed. The different forms of energy consumption and their causes in wastewater treatment process were analyzed based on thermodynamic laws and quality characteristics of the wastewater, with reasonable assumptions. The laws of energy transfer and distribution of two specific cases are expressed by the energy flow diagram. Some possible energy-saving approaches and wastewater treatment methods in the future are predicted by comparing different energy saving technologies. Based on in-depth understanding of the embodied energy in wastewaters, valuable elements such as nutrients (nitrogen, phosphorus) and heavy metals can be separated and recovered, and water resources can be reused by combining with related industries and technologies. Therefore, the goal of energy saving can be achieved by the indirect compensation of energy consumption in the wastewater treatment process.
2010, 32(5):65-70.
DOI: 10.11835/j.issn.1674-4764.2010.05.012
Abstract:
In the process of air conditioning, not only the thermal comfort but also energy saving should be considered. A method, which combines a least enthalpy difference（LED） and mixing air ratio based on the theory of enthalpy, can help to approach to comfortable zone for the air before coming into air handling unit (AHU). Then several mathematic equations of mixing process were derived based on laws of conservation of mass and energy. Eventually, the models of HVAC were established under SIMULINK environment. And the control strategies are validated in the aspects of improving comfortable effect and saving energy. It is found that LED based PID controller can achieve the requirements of better thermal comfort and energy efficiency.
In the process of air conditioning, not only the thermal comfort but also energy saving should be considered. A method, which combines a least enthalpy difference（LED） and mixing air ratio based on the theory of enthalpy, can help to approach to comfortable zone for the air before coming into air handling unit (AHU). Then several mathematic equations of mixing process were derived based on laws of conservation of mass and energy. Eventually, the models of HVAC were established under SIMULINK environment. And the control strategies are validated in the aspects of improving comfortable effect and saving energy. It is found that LED based PID controller can achieve the requirements of better thermal comfort and energy efficiency.
2012, 34(Z2):54-60.
Abstract:
This paper aims at providing a basic state-of-the-art of standards and guidelines, as well as laboratory and field studies dealing with whole-body vibration perception thresholds, and comparative analysis is given. Mechanisms of vibration perception, absolute thresholds of perception, difference thresholds and descriptors are introduced. The effects of frequency, posture, direction, duration, gender, age and noise on whole-body vibration perception thresholds are reviewed. And the problems requiring further investigation are proposed.
This paper aims at providing a basic state-of-the-art of standards and guidelines, as well as laboratory and field studies dealing with whole-body vibration perception thresholds, and comparative analysis is given. Mechanisms of vibration perception, absolute thresholds of perception, difference thresholds and descriptors are introduced. The effects of frequency, posture, direction, duration, gender, age and noise on whole-body vibration perception thresholds are reviewed. And the problems requiring further investigation are proposed.
2010, 32(4):85-89.
DOI: 10.11835/j.issn.1674-4764.2010.04.017
Abstract:
The influence of luminance level on students’ productivity, asthenopia (an eye strain), and brainfag (a mental exhaustion and depressive disorder) was studied with three typical colour temperatures of T5 fluorescent lamps. The changing rate of productivity and asthenopia were measured by using anomalistic distance determination and Анфимов alphabet test method and the changing rate of productivity was regarded as the brainfag index. It is found that medium colour temperature fluorescent lamps with appropriate exposure time can produce desirable consequences, stimulate the subjects’ cognitive ability and enhance their productivity. However, some lamps with lower or higher colour temperature produced undesirable consequences. The optimal luminances levels were thus variable and correspond to the colour temperature of lamps. The worst combination of colour temperature & luminance was identifies and should be avoided in classroom lighting design.
The influence of luminance level on students’ productivity, asthenopia (an eye strain), and brainfag (a mental exhaustion and depressive disorder) was studied with three typical colour temperatures of T5 fluorescent lamps. The changing rate of productivity and asthenopia were measured by using anomalistic distance determination and Анфимов alphabet test method and the changing rate of productivity was regarded as the brainfag index. It is found that medium colour temperature fluorescent lamps with appropriate exposure time can produce desirable consequences, stimulate the subjects’ cognitive ability and enhance their productivity. However, some lamps with lower or higher colour temperature produced undesirable consequences. The optimal luminances levels were thus variable and correspond to the colour temperature of lamps. The worst combination of colour temperature & luminance was identifies and should be avoided in classroom lighting design.
2012, 34(1):102-107.
DOI: 10.11835/j.issn.1674-4764.2012.01.020
Abstract:
Among all the measurement methods on activity of urease, indophenol blue colorimetric method, higher accuracy of the measurement results and better reproducibility, is the most widely used measurement method on activity of urease. However, this kind of method also owns some drawbacks, for examples, filtered fluid of cultivated soil is muddy and concentration of substrate has a great influence on the activity of urease. Based on the former measurement methods, four crucial parameters was taken to, such as method of filtration, time of cultivation, concentration of substrate and choice of buffer solution, the comparative tests in order to improve the accuracy of the measurement results of indophenol blue colorimetric method. The result of improved method is closer to the real activity of urease in soil with the conditions that choosing 5% concentration of substrate and pH10.0 borate buffer solution during the cultivation, extracting and filtrating with potassium chloride solution after 24-hours cultivation. The result of improved indophenol blue colorimetric method is 2.46 times better than the traditional method.
Among all the measurement methods on activity of urease, indophenol blue colorimetric method, higher accuracy of the measurement results and better reproducibility, is the most widely used measurement method on activity of urease. However, this kind of method also owns some drawbacks, for examples, filtered fluid of cultivated soil is muddy and concentration of substrate has a great influence on the activity of urease. Based on the former measurement methods, four crucial parameters was taken to, such as method of filtration, time of cultivation, concentration of substrate and choice of buffer solution, the comparative tests in order to improve the accuracy of the measurement results of indophenol blue colorimetric method. The result of improved method is closer to the real activity of urease in soil with the conditions that choosing 5% concentration of substrate and pH10.0 borate buffer solution during the cultivation, extracting and filtrating with potassium chloride solution after 24-hours cultivation. The result of improved indophenol blue colorimetric method is 2.46 times better than the traditional method.
