目的 展示一种用于描述溶解过程及其与岩土工程的耦合的方法, 预测地下洞穴的发育过程, 为天坑等地质灾害的防治提供依据 创新点 用达西尺度模型的扩散界面代替孔隙尺度模型的锐利界面来描述溶解过程, 提升研究对象的尺度和计算效率。 方法 利用体积平均法将孔隙尺度模型上推到达西尺度。 结论 达西尺度模型描述溶解过程与孔隙尺度模型的结果吻合良好, 可广泛应用于岩土工程中的各类溶解问题。 The subsoil contains many evaporites such as limestone, gypsum, and salt. Such rocks are very sensitive to water. The deposit of evaporites raises questions because of their dissolution with time and the mechanical-geotechnical impact on the neighboring zone. Depending on the configuration of the site and the location of the rocks, the dissolution can lead to surface subsidence and, for instance, the formation of sinkholes and landslides. In this study, we present an approach that describes the dissolution process and its coupling with geotechnical engineering. In the first part we set the physico-mathematical framework, the hypothesis, and the limitations in which the dissolution process is stated. The physical interface between the fluid and the rock (porous) is represented by a diffuse interface of finite thickness. We briefly describe, in the framework of porous media, the steps needed to upscale the microscopic-scale (pore-scale) model to the macroscopic scale (Darcy scale). Although the constructed method has a large range of application, we will restrict it to saline and gypsum rocks. The second part is mainly devoted to the geotechnical consequences of the dissolution of gypsum material. We then analyze the effect of dissolution in the vicinity of a soil dam or slope and the partial dissolution of a gypsum pillar by a thin layer of water. These theoretical examples show the relevance and the potential of the approach in the general framework of geoengineering problems.
目的 展示一种用于描述溶解过程及其与岩土工程的耦合的方法, 预测地下洞穴的发育过程, 为天坑等地质灾害的防治提供依据 创新点 用达西尺度模型的扩散界面代替孔隙尺度模型的锐利界面来描述溶解过程, 提升研究对象的尺度和计算效率。 方法 利用体积平均法将孔隙尺度模型上推到达西尺度。 结论 达西尺度模型描述溶解过程与孔隙尺度模型的结果吻合良好, 可广泛应用于岩土工程中的各类溶解问题。 The subsoil contains many evaporites such as limestone, gypsum, and salt. Such rocks are very sensitive to water. The deposit of evaporites raises questions because of their dissolution with time and the mechanical-geotechnical impact on the neighboring zone. Depending on the configuration of the site and the location of the rocks, the dissolution can lead to surface subsidence and, for instance, the formation of sinkholes and landslides. In this study, we present an approach that describes the dissolution process and its coupling with geotechnical engineering. In the first part we set the physico-mathematical framework, the hypothesis, and the limitations in which the dissolution process is stated. The physical interface between the fluid and the rock (porous) is represented by a diffuse interface of finite thickness. We briefly describe, in the framework of porous media, the steps needed to upscale the microscopic-scale (pore-scale) model to the macroscopic scale (Darcy scale). Although the constructed method has a large range of application, we will restrict it to saline and gypsum rocks. The second part is mainly devoted to the geotechnical consequences of the dissolution of gypsum material. We then analyze the effect of dissolution in the vicinity of a soil dam or slope and the partial dissolution of a gypsum pillar by a thin layer of water. These theoretical examples show the relevance and the potential of the approach in the general framework of geoengineering problems.
{"title":"Modelling and applications of dissolution of rocks in geoengineering","authors":"F. Laouafa, Jianwei Guo, M. Quintard","doi":"10.1631/jzus.A2200169","DOIUrl":"https://doi.org/10.1631/jzus.A2200169","url":null,"abstract":"目的 展示一种用于描述溶解过程及其与岩土工程的耦合的方法, 预测地下洞穴的发育过程, 为天坑等地质灾害的防治提供依据 创新点 用达西尺度模型的扩散界面代替孔隙尺度模型的锐利界面来描述溶解过程, 提升研究对象的尺度和计算效率。 方法 利用体积平均法将孔隙尺度模型上推到达西尺度。 结论 达西尺度模型描述溶解过程与孔隙尺度模型的结果吻合良好, 可广泛应用于岩土工程中的各类溶解问题。 The subsoil contains many evaporites such as limestone, gypsum, and salt. Such rocks are very sensitive to water. The deposit of evaporites raises questions because of their dissolution with time and the mechanical-geotechnical impact on the neighboring zone. Depending on the configuration of the site and the location of the rocks, the dissolution can lead to surface subsidence and, for instance, the formation of sinkholes and landslides. In this study, we present an approach that describes the dissolution process and its coupling with geotechnical engineering. In the first part we set the physico-mathematical framework, the hypothesis, and the limitations in which the dissolution process is stated. The physical interface between the fluid and the rock (porous) is represented by a diffuse interface of finite thickness. We briefly describe, in the framework of porous media, the steps needed to upscale the microscopic-scale (pore-scale) model to the macroscopic scale (Darcy scale). Although the constructed method has a large range of application, we will restrict it to saline and gypsum rocks. The second part is mainly devoted to the geotechnical consequences of the dissolution of gypsum material. We then analyze the effect of dissolution in the vicinity of a soil dam or slope and the partial dissolution of a gypsum pillar by a thin layer of water. These theoretical examples show the relevance and the potential of the approach in the general framework of geoengineering problems.","PeriodicalId":17508,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"111 1","pages":"20-36"},"PeriodicalIF":3.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76775411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
目的 阐明功能性神经元设计的物理机理, 揭示能量调控神经元放电模态和突触活性的物理机理, 并论证神经元自适 应性选频的路径和神经元网络内异质性和缺陷的形成。 创新点 1. 建立了包含表达电磁感应、热效应和温度感知、光敏、压电感知和磁场感知的系列神经元模型; 2. 定义了 神经元中哈密顿能量并解释其来源和计算方法; 3. 指出哈密顿能量对神经元突触调控的物理机理和方法; 4. 解 释了听觉神经元和视觉神经元在外界刺激下的选频响应机理; 5. 解释了神经元网络内异质性和缺陷形成的能 量机理。 方法 把忆阻器、热敏电阻、光电管、压电陶瓷、约瑟夫森结等嵌入简单的电感-电容和电阻耦合的神经元电路, 实 现对外界物理信号的捕获和感知。从神经元电路场能量方程和赫姆霍兹定理分别得出功能神经元模型的能量函 数, 确认其表达式的唯一性和一致性。以神经元能量函数为控制开关, 对神经元突触进行自适应控制来实现能 量平衡。 结论 1. 特定物理器件嵌入神经元电路可以增强其物理感知能力; 2. 能量驱动和调控可以有效控制神经元和神经元 网络放电模态和时空斑图; 3. 生物神经元的多重自适应性源于能量流的平衡分配。 Diffusive intracellular and extracellular ions induce a gradient electromagnetic field that regulates membrane potential, and energy injection from external stimuli breaks the energy balance between the magnetic and electric fields in a cell. Indeed, any activation of biophysical function and self-adaption of biological neurons may be dependent on energy flow, and synapse connection is controlled to reach energy balance between neurons. When more neurons are clustered and gathered closely, field energy is exchanged and shape formation is induced to achieve local energy balance. As a result, the coexistence of multiple firing modes in neural activities is fostered to prevent the occurrence of bursting synchronization and seizure. In this review, a variety of biophysical neuron models are presented and explained in terms of their physical aspects, and the controllability of functional synapses, formation of heterogeneity, and defects are clarified for knowing the synchronization stability and cooperation between functional regions. These models and findings are summarized to provide new insights into nonlinear physics and computational neuroscience.
目的 阐明功能性神经元设计的物理机理, 揭示能量调控神经元放电模态和突触活性的物理机理, 并论证神经元自适 应性选频的路径和神经元网络内异质性和缺陷的形成。 创新点 1. 建立了包含表达电磁感应、热效应和温度感知、光敏、压电感知和磁场感知的系列神经元模型; 2. 定义了 神经元中哈密顿能量并解释其来源和计算方法; 3. 指出哈密顿能量对神经元突触调控的物理机理和方法; 4. 解 释了听觉神经元和视觉神经元在外界刺激下的选频响应机理; 5. 解释了神经元网络内异质性和缺陷形成的能 量机理。 方法 把忆阻器、热敏电阻、光电管、压电陶瓷、约瑟夫森结等嵌入简单的电感-电容和电阻耦合的神经元电路, 实 现对外界物理信号的捕获和感知。从神经元电路场能量方程和赫姆霍兹定理分别得出功能神经元模型的能量函 数, 确认其表达式的唯一性和一致性。以神经元能量函数为控制开关, 对神经元突触进行自适应控制来实现能 量平衡。 结论 1. 特定物理器件嵌入神经元电路可以增强其物理感知能力; 2. 能量驱动和调控可以有效控制神经元和神经元 网络放电模态和时空斑图; 3. 生物神经元的多重自适应性源于能量流的平衡分配。 Diffusive intracellular and extracellular ions induce a gradient electromagnetic field that regulates membrane potential, and energy injection from external stimuli breaks the energy balance between the magnetic and electric fields in a cell. Indeed, any activation of biophysical function and self-adaption of biological neurons may be dependent on energy flow, and synapse connection is controlled to reach energy balance between neurons. When more neurons are clustered and gathered closely, field energy is exchanged and shape formation is induced to achieve local energy balance. As a result, the coexistence of multiple firing modes in neural activities is fostered to prevent the occurrence of bursting synchronization and seizure. In this review, a variety of biophysical neuron models are presented and explained in terms of their physical aspects, and the controllability of functional synapses, formation of heterogeneity, and defects are clarified for knowing the synchronization stability and cooperation between functional regions. These models and findings are summarized to provide new insights into nonlinear physics and computational neuroscience.
{"title":"Biophysical neurons, energy, and synapse controllability: a review","authors":"Jun Ma","doi":"10.1631/jzus.A2200469","DOIUrl":"https://doi.org/10.1631/jzus.A2200469","url":null,"abstract":"目的 阐明功能性神经元设计的物理机理, 揭示能量调控神经元放电模态和突触活性的物理机理, 并论证神经元自适 应性选频的路径和神经元网络内异质性和缺陷的形成。 创新点 1. 建立了包含表达电磁感应、热效应和温度感知、光敏、压电感知和磁场感知的系列神经元模型; 2. 定义了 神经元中哈密顿能量并解释其来源和计算方法; 3. 指出哈密顿能量对神经元突触调控的物理机理和方法; 4. 解 释了听觉神经元和视觉神经元在外界刺激下的选频响应机理; 5. 解释了神经元网络内异质性和缺陷形成的能 量机理。 方法 把忆阻器、热敏电阻、光电管、压电陶瓷、约瑟夫森结等嵌入简单的电感-电容和电阻耦合的神经元电路, 实 现对外界物理信号的捕获和感知。从神经元电路场能量方程和赫姆霍兹定理分别得出功能神经元模型的能量函 数, 确认其表达式的唯一性和一致性。以神经元能量函数为控制开关, 对神经元突触进行自适应控制来实现能 量平衡。 结论 1. 特定物理器件嵌入神经元电路可以增强其物理感知能力; 2. 能量驱动和调控可以有效控制神经元和神经元 网络放电模态和时空斑图; 3. 生物神经元的多重自适应性源于能量流的平衡分配。 Diffusive intracellular and extracellular ions induce a gradient electromagnetic field that regulates membrane potential, and energy injection from external stimuli breaks the energy balance between the magnetic and electric fields in a cell. Indeed, any activation of biophysical function and self-adaption of biological neurons may be dependent on energy flow, and synapse connection is controlled to reach energy balance between neurons. When more neurons are clustered and gathered closely, field energy is exchanged and shape formation is induced to achieve local energy balance. As a result, the coexistence of multiple firing modes in neural activities is fostered to prevent the occurrence of bursting synchronization and seizure. In this review, a variety of biophysical neuron models are presented and explained in terms of their physical aspects, and the controllability of functional synapses, formation of heterogeneity, and defects are clarified for knowing the synchronization stability and cooperation between functional regions. These models and findings are summarized to provide new insights into nonlinear physics and computational neuroscience.","PeriodicalId":17508,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"1 1","pages":"109-129"},"PeriodicalIF":3.2,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90214666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xia Yan, Piyang Liu, Zhao-qin Huang, Hai Sun, Kai Zhang, Jun-feng Wang, Jun Yao
目的 在页岩气藏CO_2吞吐过程中, 水力裂缝处于循环载荷作用下时, 极易发生不可逆变形(变形滞后), 影响吞吐效果。本文旨在建立考虑水力裂缝变形滞后的页岩气藏CO_2吞吐流固耦合模型, 形成相应的高效求解方法, 并开展流固耦合数值模拟研究, 以揭示变形滞后对CO_2吞吐的影响规律。 创新点 1. 建立考虑水力裂缝变形滞后、复杂裂缝系统和特殊流动机理的页岩气藏多组分流固耦合模型, 并形成相应的三维高效数值模拟技术; 2. 揭示水力裂缝变形滞后对页岩气藏CO_2吞吐的影响规律。 方法 1. 建立考虑水力裂缝变形滞后、复杂裂缝系统和特殊流动机理的页岩气藏多组分流固耦合模型; 2. 基于结构化网格构造高效稳定的多组分流固耦合模型数值求解算法; 3. 通过流固耦合数值模拟, 揭示水力裂缝变形滞后对页岩气藏CO_2吞吐的影响规律。 结论 1. 水力裂缝变形滞后会阻碍 CO_2注入期间裂缝渗透率的恢复, 对CO_2吞吐有负面影响; 2. 较低的初始水力裂缝导流能力和生产压力、较晚的吞吐启动时间、较高的注入压力和较多的循环次数均会增强变形滞后的负面影响; 3. CO_2吞吐效果与初始水力裂缝导流能力、吞吐启动时间、注入压力和循环次数呈正相关, 与生产压力呈负相关。 As a promising enhanced gas recovery technique, CO_2 huff-n-puff has attracted great attention recently. However, hydraulic fracture deformation hysteresis is rarely considered, and its effect on CO_2 huff-n-puff performance is not well understood. In this study, we present a fully coupled multi-component flow and geomechanics model for simulating CO_2 huff-n-puff in shale gas reservoirs considering hydraulic fracture deformation hysteresis. Specifically, a shale gas reservoir after hydraulic fracturing is modeled using an efficient hybrid model incorporating an embedded discrete fracture model (EDFM), multiple porosity model, and single porosity model. In flow equations, Fick’s law, extended Langmuir isotherms, and the Peng-Robinson equation of state are used to describe the molecular diffusion, multi-component adsorption, and gas properties, respectively. In relation to geomechanics, a path-dependent constitutive law is applied for the hydraulic fracture deformation hysteresis. The finite volume method (FVM) and the stabilized extended finite element method (XFEM) are applied to discretize the flow and geomechanics equations, respectively. We then solve the coupled model using the fixed-stress split iterative method. Finally, we verify the presented method using several numerical examples, and apply it to investigate the effect of hydraulic fracture deformation hysteresis on CO_2 huff-n-puff performance in a 3D shale gas reservoir. Numerical results show that hydraulic fracture deformation hysteresis has some negative effects on CO_2 huff-n-puff performance. The effects are sensitive to the initial conductivity of hydraulic fracture, production pressure, starting time of huff-n-puff, injection pressure, and huff-n-puff cycle number.
目的 在页岩气藏CO_2吞吐过程中, 水力裂缝处于循环载荷作用下时, 极易发生不可逆变形(变形滞后), 影响吞吐效果。本文旨在建立考虑水力裂缝变形滞后的页岩气藏CO_2吞吐流固耦合模型, 形成相应的高效求解方法, 并开展流固耦合数值模拟研究, 以揭示变形滞后对CO_2吞吐的影响规律。 创新点 1. 建立考虑水力裂缝变形滞后、复杂裂缝系统和特殊流动机理的页岩气藏多组分流固耦合模型, 并形成相应的三维高效数值模拟技术; 2. 揭示水力裂缝变形滞后对页岩气藏CO_2吞吐的影响规律。 方法 1. 建立考虑水力裂缝变形滞后、复杂裂缝系统和特殊流动机理的页岩气藏多组分流固耦合模型; 2. 基于结构化网格构造高效稳定的多组分流固耦合模型数值求解算法; 3. 通过流固耦合数值模拟, 揭示水力裂缝变形滞后对页岩气藏CO_2吞吐的影响规律。 结论 1. 水力裂缝变形滞后会阻碍 CO_2注入期间裂缝渗透率的恢复, 对CO_2吞吐有负面影响; 2. 较低的初始水力裂缝导流能力和生产压力、较晚的吞吐启动时间、较高的注入压力和较多的循环次数均会增强变形滞后的负面影响; 3. CO_2吞吐效果与初始水力裂缝导流能力、吞吐启动时间、注入压力和循环次数呈正相关, 与生产压力呈负相关。 As a promising enhanced gas recovery technique, CO_2 huff-n-puff has attracted great attention recently. However, hydraulic fracture deformation hysteresis is rarely considered, and its effect on CO_2 huff-n-puff performance is not well understood. In this study, we present a fully coupled multi-component flow and geomechanics model for simulating CO_2 huff-n-puff in shale gas reservoirs considering hydraulic fracture deformation hysteresis. Specifically, a shale gas reservoir after hydraulic fracturing is modeled using an efficient hybrid model incorporating an embedded discrete fracture model (EDFM), multiple porosity model, and single porosity model. In flow equations, Fick’s law, extended Langmuir isotherms, and the Peng-Robinson equation of state are used to describe the molecular diffusion, multi-component adsorption, and gas properties, respectively. In relation to geomechanics, a path-dependent constitutive law is applied for the hydraulic fracture deformation hysteresis. The finite volume method (FVM) and the stabilized extended finite element method (XFEM) are applied to discretize the flow and geomechanics equations, respectively. We then solve the coupled model using the fixed-stress split iterative method. Finally, we verify the presented method using several numerical examples, and apply it to investigate the effect of hydraulic fracture deformation hysteresis on CO_2 huff-n-puff performance in a 3D shale gas reservoir. Numerical results show that hydraulic fracture deformation hysteresis has some negative effects on CO_2 huff-n-puff performance. The effects are sensitive to the initial conductivity of hydraulic fracture, production pressure, starting time of huff-n-puff, injection pressure, and huff-n-puff cycle number.
{"title":"Effect of hydraulic fracture deformation hysteresis on CO_2 huff-n-puff performance in shale gas reservoirs","authors":"Xia Yan, Piyang Liu, Zhao-qin Huang, Hai Sun, Kai Zhang, Jun-feng Wang, Jun Yao","doi":"10.1631/jzus.A2200142","DOIUrl":"https://doi.org/10.1631/jzus.A2200142","url":null,"abstract":"目的 在页岩气藏CO_2吞吐过程中, 水力裂缝处于循环载荷作用下时, 极易发生不可逆变形(变形滞后), 影响吞吐效果。本文旨在建立考虑水力裂缝变形滞后的页岩气藏CO_2吞吐流固耦合模型, 形成相应的高效求解方法, 并开展流固耦合数值模拟研究, 以揭示变形滞后对CO_2吞吐的影响规律。 创新点 1. 建立考虑水力裂缝变形滞后、复杂裂缝系统和特殊流动机理的页岩气藏多组分流固耦合模型, 并形成相应的三维高效数值模拟技术; 2. 揭示水力裂缝变形滞后对页岩气藏CO_2吞吐的影响规律。 方法 1. 建立考虑水力裂缝变形滞后、复杂裂缝系统和特殊流动机理的页岩气藏多组分流固耦合模型; 2. 基于结构化网格构造高效稳定的多组分流固耦合模型数值求解算法; 3. 通过流固耦合数值模拟, 揭示水力裂缝变形滞后对页岩气藏CO_2吞吐的影响规律。 结论 1. 水力裂缝变形滞后会阻碍 CO_2注入期间裂缝渗透率的恢复, 对CO_2吞吐有负面影响; 2. 较低的初始水力裂缝导流能力和生产压力、较晚的吞吐启动时间、较高的注入压力和较多的循环次数均会增强变形滞后的负面影响; 3. CO_2吞吐效果与初始水力裂缝导流能力、吞吐启动时间、注入压力和循环次数呈正相关, 与生产压力呈负相关。 As a promising enhanced gas recovery technique, CO_2 huff-n-puff has attracted great attention recently. However, hydraulic fracture deformation hysteresis is rarely considered, and its effect on CO_2 huff-n-puff performance is not well understood. In this study, we present a fully coupled multi-component flow and geomechanics model for simulating CO_2 huff-n-puff in shale gas reservoirs considering hydraulic fracture deformation hysteresis. Specifically, a shale gas reservoir after hydraulic fracturing is modeled using an efficient hybrid model incorporating an embedded discrete fracture model (EDFM), multiple porosity model, and single porosity model. In flow equations, Fick’s law, extended Langmuir isotherms, and the Peng-Robinson equation of state are used to describe the molecular diffusion, multi-component adsorption, and gas properties, respectively. In relation to geomechanics, a path-dependent constitutive law is applied for the hydraulic fracture deformation hysteresis. The finite volume method (FVM) and the stabilized extended finite element method (XFEM) are applied to discretize the flow and geomechanics equations, respectively. We then solve the coupled model using the fixed-stress split iterative method. Finally, we verify the presented method using several numerical examples, and apply it to investigate the effect of hydraulic fracture deformation hysteresis on CO_2 huff-n-puff performance in a 3D shale gas reservoir. Numerical results show that hydraulic fracture deformation hysteresis has some negative effects on CO_2 huff-n-puff performance. The effects are sensitive to the initial conductivity of hydraulic fracture, production pressure, starting time of huff-n-puff, injection pressure, and huff-n-puff cycle number.","PeriodicalId":17508,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"22 1","pages":"37-55"},"PeriodicalIF":3.2,"publicationDate":"2022-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77049321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the high-humidity, hot-summer-cold-winter (HSCW) zone of China, the moisture buffering effect in the envelope is found to be significant in optimum insulation thickness. However, few studies have considered the effects of indoor moisture buffering on the optimum insulation thickness and energy consumption. In this study, we considered the energy load of an exterior wall under moisture transfer from the outdoor to the indoor environment. An optimum insulation thickness was obtained by integrating the P1−P2 model. A residential building was selected for the case study to verify the proposed method. Finally, a comparison was made with two other widely used methods, namely the transient heat transfer model (TH) and the coupled heat and moisture transfer model (CHM). The results indicated that the indoor moisture buffering effect on the optimum insulation thickness is 2.54 times greater than the moisture buffering effect in the envelope, and the two moisture buffering effects make opposing contributions to the optimum insulation thickness. Therefore, when TH or CHM was used without considering the indoor moisture buffering effect, the optimum insulation thickness of the southern wall under one air change per hour (1 ACH) and 100% normal heat source may be overestimated by 2.13% to 3. 59%, and the annual energy load on a single wall may be underestimated by 10.10% to 11.44%. The decrease of airtightness and the increase of indoor heat sources may result in a slight reduction of optimum insulation thickness. This study will enable professionals to consider the effects of moisture buffering on the design of insulation thickness.
{"title":"Optimum insulation thickness of external walls by integrating indoor moisture buffering effect: a case study in the hot-summer-cold-winter zone of China","authors":"Yan Feng, Zitao Yu, Jiang Lu, Xu Xu","doi":"10.1631/2023.A2200158","DOIUrl":"https://doi.org/10.1631/2023.A2200158","url":null,"abstract":"In the high-humidity, hot-summer-cold-winter (HSCW) zone of China, the moisture buffering effect in the envelope is found to be significant in optimum insulation thickness. However, few studies have considered the effects of indoor moisture buffering on the optimum insulation thickness and energy consumption. In this study, we considered the energy load of an exterior wall under moisture transfer from the outdoor to the indoor environment. An optimum insulation thickness was obtained by integrating the P1−P2 model. A residential building was selected for the case study to verify the proposed method. Finally, a comparison was made with two other widely used methods, namely the transient heat transfer model (TH) and the coupled heat and moisture transfer model (CHM). The results indicated that the indoor moisture buffering effect on the optimum insulation thickness is 2.54 times greater than the moisture buffering effect in the envelope, and the two moisture buffering effects make opposing contributions to the optimum insulation thickness. Therefore, when TH or CHM was used without considering the indoor moisture buffering effect, the optimum insulation thickness of the southern wall under one air change per hour (1 ACH) and 100% normal heat source may be overestimated by 2.13% to 3. 59%, and the annual energy load on a single wall may be underestimated by 10.10% to 11.44%. The decrease of airtightness and the increase of indoor heat sources may result in a slight reduction of optimum insulation thickness. This study will enable professionals to consider the effects of moisture buffering on the design of insulation thickness.","PeriodicalId":17508,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"104 1","pages":"998 - 1012"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76862344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuai Shao, Kailin Zhang, Yuan Yao, Yi Liu, Jun Gu
In this paper, a numerical simulation model of the flow field in a gearbox with an oil volume adjusting device is established for the first time to study its influence on the lubrication characteristics of a high-speed electric multiple unit (EMU) gearbox. The moving particle semi-implicit (MPS) method is used to numerically simulate the internal flow field of the gearbox of the high-speed EMU under working conditions. The effects of the velocity of the high-speed EMU, the immersion depth, and the oil sump temperature on the power loss of the gears and the lubricant quantity of each bearing are studied and provide an effective tool for the quantitative evaluation of the lubrication characteristics of the gearbox. The lubrication characteristics of the gearbox under different working conditions are studied when the oil volume adjusting device is closed and opened. The results show that the oil volume adjusting device mainly changes the amount of lubricant stirred by the output gear by changing the flow rate of lubricant from the cavity pinion (Cavity P) to the cavity gear (Cavity G), and thus affects the power loss of gears and the lubricant quantity of each bearing.
{"title":"Investigations on lubrication characteristics of high-speed electric multiple unit gearbox by oil volume adjusting device","authors":"Shuai Shao, Kailin Zhang, Yuan Yao, Yi Liu, Jun Gu","doi":"10.1631/2023.A2200274","DOIUrl":"https://doi.org/10.1631/2023.A2200274","url":null,"abstract":"In this paper, a numerical simulation model of the flow field in a gearbox with an oil volume adjusting device is established for the first time to study its influence on the lubrication characteristics of a high-speed electric multiple unit (EMU) gearbox. The moving particle semi-implicit (MPS) method is used to numerically simulate the internal flow field of the gearbox of the high-speed EMU under working conditions. The effects of the velocity of the high-speed EMU, the immersion depth, and the oil sump temperature on the power loss of the gears and the lubricant quantity of each bearing are studied and provide an effective tool for the quantitative evaluation of the lubrication characteristics of the gearbox. The lubrication characteristics of the gearbox under different working conditions are studied when the oil volume adjusting device is closed and opened. The results show that the oil volume adjusting device mainly changes the amount of lubricant stirred by the output gear by changing the flow rate of lubricant from the cavity pinion (Cavity P) to the cavity gear (Cavity G), and thus affects the power loss of gears and the lubricant quantity of each bearing.","PeriodicalId":17508,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"21 1","pages":"1013 - 1026"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81822843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhengliang Huang, Yun-bo Yu, Qiuyue Song, Yao Yang, Jingyuan Sun, Jingdai Wang, Yong-rong Yang
A novel central hole-expansion phenomenon is identified, in which the cation-exchange resin is pyrolyzed in a mixed atmosphere of nitrogen and oxygen at 400–500 °C. In this reaction, the reaction path is predictable and always starts from the center of the resin particle to form a central hole, then continues and expands around the hole, finally forming a uniformly distributed hole group; the particle surface remains intact. Analysis shows that this formation mode is due to the different reaction paths of sulfonic groups between the surface and interior of the particle, caused by the temperature difference. On the surface, transformation reactions happen at high temperatures (410–500 °C) to form stable organic sulfur structures, while decomposition occurs inside the particle at a relatively low temperature (<410 °C) and promotes complete pyrolysis of the copolymer matrix to form holes.
{"title":"Hole-growth phenomenon during pyrolysis of a cation-exchange resin particle","authors":"Zhengliang Huang, Yun-bo Yu, Qiuyue Song, Yao Yang, Jingyuan Sun, Jingdai Wang, Yong-rong Yang","doi":"10.1631/2023.A2200233","DOIUrl":"https://doi.org/10.1631/2023.A2200233","url":null,"abstract":"A novel central hole-expansion phenomenon is identified, in which the cation-exchange resin is pyrolyzed in a mixed atmosphere of nitrogen and oxygen at 400–500 °C. In this reaction, the reaction path is predictable and always starts from the center of the resin particle to form a central hole, then continues and expands around the hole, finally forming a uniformly distributed hole group; the particle surface remains intact. Analysis shows that this formation mode is due to the different reaction paths of sulfonic groups between the surface and interior of the particle, caused by the temperature difference. On the surface, transformation reactions happen at high temperatures (410–500 °C) to form stable organic sulfur structures, while decomposition occurs inside the particle at a relatively low temperature (<410 °C) and promotes complete pyrolysis of the copolymer matrix to form holes.","PeriodicalId":17508,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"43 1","pages":"974 - 987"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73681787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
3D bioprinting has the capability to create 3D cellular constructs with the desired shape using a layer-by-layer approach. Inkjet 3D bioprinting, as a key component of 3D bioprinting, relies on the deposition of cell-laden droplets to create native-like tissues/organs which are envisioned to be transplantable into human body for replacing damaged ones. Benefiting from its superiorities such as high printing resolution and deposition accuracy, inkjet 3D bioprinting has been widely applied to various areas, including, but not limited to, tissue engineering and drug screening in pharmaceutics. Even though inkjet 3D bioprinting has proved its feasibility and versatility in various fields, the current applications of inkjet 3D bioprinting are still limited by the printing technique and material selection. This review, which specifically focuses on inkjet 3D bioprinting, firstly summarizes the techniques, materials, and applications of inkjet 3D bioprinting in tissue engineering and drug screening, subsequently discusses the major challenges that inkjet 3D bioprinting is facing, and lastly summarizes potential solutions to those challenges.
{"title":"Inkjet 3D bioprinting for tissue engineering and pharmaceutics","authors":"Deng-ke Zhao, Hengjuan Xu, J. Yin, Hua-yong Yang","doi":"10.1631/2023.A2200569","DOIUrl":"https://doi.org/10.1631/2023.A2200569","url":null,"abstract":"3D bioprinting has the capability to create 3D cellular constructs with the desired shape using a layer-by-layer approach. Inkjet 3D bioprinting, as a key component of 3D bioprinting, relies on the deposition of cell-laden droplets to create native-like tissues/organs which are envisioned to be transplantable into human body for replacing damaged ones. Benefiting from its superiorities such as high printing resolution and deposition accuracy, inkjet 3D bioprinting has been widely applied to various areas, including, but not limited to, tissue engineering and drug screening in pharmaceutics. Even though inkjet 3D bioprinting has proved its feasibility and versatility in various fields, the current applications of inkjet 3D bioprinting are still limited by the printing technique and material selection. This review, which specifically focuses on inkjet 3D bioprinting, firstly summarizes the techniques, materials, and applications of inkjet 3D bioprinting in tissue engineering and drug screening, subsequently discusses the major challenges that inkjet 3D bioprinting is facing, and lastly summarizes potential solutions to those challenges.","PeriodicalId":17508,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"46 1","pages":"955 - 973"},"PeriodicalIF":3.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85723226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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