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Lateral displacement of soft ground under vacuum pressure and surcharge load

Chin-Yee ONG, Jin-Chun CHAI

《结构与土木工程前沿(英文)》 2011年 第5卷 第2期   页码 239-248 doi: 10.1007/s11709-011-0110-1

摘要: Surcharge load (e.g. embankment fill) will induce settlement and outward lateral displacement, while vacuum pressure will induce settlement and inward lateral displacement of a ground. Ideally, combination of surcharge load and vacuum pressure can reduce or minimize the lateral displacement. Laboratory large scale model (length: 1.50 m, width: ~0.62 m, height: 0.85 m) tests and finite element analyses (FEA) were conducted to investigate the main influencing factors on lateral displacement of a soft clayey ground under the combination of vacuum pressure and surcharge load. For the conditions investigated, the results indicate that the outward lateral displacement increases with the increase of the ratio of surcharge load to vacuum pressure ( ) and the loading rate of the surcharge load ( ). Also, it is shown that for a given and condition, lateral displacement reduces with the increase of the initial undrained shear strength ( ) of the ground. To predict the lateral displacement of a ground under the combination of surcharge load and vacuum pressure, the loading conditions in terms of and , and value of the ground have to be considered.

关键词: vacuum consolidation     lateral displacement     PVD     finite element analysis     surcharge load    

Split-order consolidation optimization for online supermarkets: Process analysis and optimization models

《工程管理前沿(英文)》   页码 499-516 doi: 10.1007/s42524-022-0221-5

摘要: The large-scale online supermarket is a newly emerging online retailing mode which brings great convenience to people. Online supermarkets are characterized by having large amounts of daily orders with potentially multiple items, diverse delivery times, and a high order-split rate. Multiple shipments for one order caused by order splitting result in high cost and disturbance and a large number of discarded consumable packages at online retailers and customers, causing severe damage to the environment. Accordingly, research on split-order consolidation fulfilment is critical for the advancement of the practice and theory in the context of highly complex online retailing. This paper first analyzes the characteristics and the challenges associated with the split-order consolidation problem that online supermarket is confronting and summarizes the new operational process of split-order consolidation fulfilment. Then, a time–space network optimization model is built, and its corresponding solution algorithm is presented to solve the questions of where and when to consolidate the split orders. Finally, the computation results of the numerical experiments are provided to verify the effectiveness of the algorithm, and a sensitivity analysis of the relevant parameters is performed. This work highlights the effect of order consolidation processes and fulfilment methods on the order fulfilment decision-making for online supermarkets. The purpose of this article is to help pave the way for more effective online supermarket management and order implementation.

关键词: online supermarkets     split-order consolidation     time–space network     genetic algorithm    

A method for predicting consolidation settlements of floating column improved clayey subsoil

Jinchun CHAI, Supasit PONGSIVASATHIT,

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 241-251 doi: 10.1007/s11709-010-0024-3

摘要: A method of predicting the consolidation settlement-time curve of floating soil-cement column on improved soft clayey subsoil has been proposed. The degree of the consolidation (()) of the system is calculated by the double soil-layer consolidation theory, and the methods for evaluating the equivalent hydraulic conductivity () and the coefficient of volume compressibility () of the part of the column improved layer have been proposed. The effectiveness of the method was verified by comparing predictions with the results of finite element analysis (FEA) using a unit cell model. The consolidation settlement (()) can be calculated by the method of treating a part of the column improved layer as an unimproved layer and using the corresponding average () value. By comparing the predicted results with the measurements of laboratory model tests and three case histories in Fukuoka, Japan, the effectiveness of the proposed methods has been verified. It is suggested that the method can be used for designing the soft clayey subsoil improvement using floating soil-cement columns.

关键词: cement depth mixing     ground improvement     consolidation     settlement    

One-dimensional consolidation of over-consolidated soil under time-dependent loading

XIE Kanghe, WANG Kun, CHEN Guohong, HU Anfeng

《结构与土木工程前沿(英文)》 2008年 第2卷 第1期   页码 67-72 doi: 10.1007/s11709-008-0009-7

摘要: The problem of one-dimensional consolidation of over-consolidated saturated soil under time-dependent loading was studied based on semi-analytical method. The relevant computer code was developed by FORTRAN programming, and one-dimensional consolidation behavior of over-consolidated soil was investigated. It is shown that, unlike this described by traditional Terzaghi’s consolidation theory, the rate of excess pore water pressure dissipation is different from that of settlement developing. The magnitude of load and that of pre-consolidation pressure as well as the loading rate has all significant influence on consolidation. With the increasing of pre-consolidation pressure and loading rate, the rate of consolidation increases correspondingly. However, an increase in load will slow down the consolidation rate.

关键词: different     FORTRAN programming     Terzaghi ’     pre-consolidation     magnitude    

Numerical study of conduction and radiation heat losses from vacuum annulus in parabolic trough receivers

Dongqiang LEI, Yucong REN, Zhifeng WANG

《能源前沿(英文)》 2022年 第16卷 第6期   页码 1048-1059 doi: 10.1007/s11708-020-0670-7

摘要: Parabolic trough receiver is a key component to convert solar energy into thermal energy in the parabolic trough solar system. The heat loss of the receiver has an important influence on the thermal efficiency and the operating cost of the power station. In this paper, conduction and radiation heat losses are analyzed respectively to identify the heat loss mechanism of the receiver. A 2-D heat transfer model is established by using the direct simulation Monte Carlo method for rarefied gas flow and heat transfer within the annulus of the receiver to predict the conduction heat loss caused by residual gases. The numerical results conform to the experimental results, and show the temperature of the glass envelope and heat loss for various conditions in detail. The effects of annulus pressure, gas species, temperature of heat transfer fluid, and annulus size on the conduction and radiation heat losses are systematically analyzed. Besides, the main factors that cause heat loss are analyzed, providing a theoretical basis for guiding the improvement of receiver, as well as the operation and maintenance strategy to reduce heat loss.

关键词: parabolic trough receiver     vacuum annulus     rarefied gas     DSMC (direct simulation Monte Carlo)     heat loss    

Dimensionality reduction and prediction of soil consolidation coefficient using random forest coupling

Hai-Bang LY; Huong-Lan Thi VU; Lanh Si HO; Binh Thai PHAM

《结构与土木工程前沿(英文)》 2022年 第16卷 第2期   页码 224-238 doi: 10.1007/s11709-022-0812-6

摘要: The consolidation coefficient of soil (Cv) is a crucial parameter used for the design of structures leaned on soft soi. In general, the Cv is determined experimentally in the laboratory. However, the experimental tests are time-consuming as well as expensive. Therefore, researchers tried several ways to determine Cv via other simple soil parameters. In this study, we developed a hybrid model of Random Forest coupling with a Relief algorithm (RF-RL) to predict the Cv of soil. To conduct this study, a database of soil parameters collected from a case study region in Vietnam was used for modeling. The performance of the proposed models was assessed via statistical indicators, namely Coefficient of determination (R2), Root Mean Squared Error (RMSE), and Mean Absolute Error (MAE). The proposal models were constructed with four sets of soil variables, including 6, 7, 8, and 13 inputs. The results revealed that all models performed well with a high performance (R2 > 0.980). Although the RF-RL model with 13 variables has the highest prediction accuracy ( R2 = 0.9869), the difference compared with other models was negligible (i.e., R2 = 0.9824, 0.9850, 0.9825 for the cases with 6, 7, 8 inputs, respectively). Thus, it can be concluded that the hybrid model of RF-RL can be employed to predict Cv based on the basic soil parameters.

关键词: soil consolidation coefficient     machine learning     random forest     Relief    

syndrome and toxic epidermal necrolysis in China: evaluation of risk models and new predictor of pulmonary consolidation

Yanhong Shou, Lu Yang, Yongsheng Yang, Xiaohua Zhu, Feng Li, Bo Yin, Yingyan Zheng, Jinhua Xu

《医学前沿(英文)》 2021年 第15卷 第4期   页码 585-593 doi: 10.1007/s11684-020-0817-2

摘要: Stevens--Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare but severe diseases. This study aimed to validate the predictive ability of risk models in patients with SJS/TEN and propose possible refinement in China. Patients in the Department of Dermatology of Huashan Hospital from January 2008 to January 2019 were included. Results showed that the severity-of-illness score for TEN (SCORTEN) had a good discrimination (area under the receiver operating characteristic curve (AUC), 0.78), and it was superior to auxiliary score (AS) and ABCD-10, which indicates age, bicarbonate level, cancer, dialysis, and 10% involved body surface area (AUC, 0.69 and 0.68, respectively). The calibration of SCORTEN (Hosmer–Lemeshow goodness-of-fit test, = 0.69) was also better than that of AS ( = 0.25) and ABCD-10 ( = 0.55). SCORTEN and ABCD-10 were similar (Brier score (BS), 0.04 and 0.04) in terms of accuracy of predictions. In addition, the imaging appearance of pulmonary consolidation on computed tomography was associated with high mortality. Refined models were formed using the variables and this imaging appearance. The refined AS and ABCD-10 models were similar in discrimination compared with the original SCORTEN (0.74 vs. 0.78, = 0.23; 0.74 vs. 0.78, = 0.30, respectively). Therefore, SCORTEN showed good discrimination performance, calibration, and accuracy, and refined AS or ABCD-10 model may be an option when SCORTEN variables are not available.

关键词: Stevens–Johnson syndrome     toxic epidermal necrolysis     auxiliary score     ABCD-10     pulmonary consolidation    

interconnected nano-channels into polyvinylidene fluoride membranes for desalination applications by vacuum

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1162-1182 doi: 10.1007/s11705-022-2276-6

摘要: In the present research, for the first time, lycopodium as a novel nanofiller was incorporated into a polyvinylidene fluoride matrix to fabricate lycopodium/polyvinylidene fluoride flat-sheet membrane for desalination applications by vacuum membrane distillation process. The prepared lycopodium/polyvinylidene fluoride membranes and lycopodium were characterized by field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared, energy dispersive X-ray, and mapping analyses. Water contact angle and liquid entry pressure measurements were also performed. Response surface methodology was applied to optimize membrane structure and performance. The optimized lycopodium/polyvinylidene fluoride membrane exhibits superior performance compared to the neat polyvinylidene fluoride membrane in terms of flux, salt rejection, water contact angle, and hydrophobicity. In vacuum membrane distillation experiments, using a 15000 ppm NaCl solution as a feed at 70 °C, the neat polyvinylidene fluoride membrane, optimum membrane, and agglomerated membrane (with high lycopodium loading) demonstrated 3.80, 25.20, and 14.83 LMH flux and 63.30%, 99.99%, 99.96% salt rejection, respectively. This improvement in flux and salt rejection of the optimized membrane was related to the presence of lycopodium with hydrophobic nature and interconnected nano-channels in membrane structure. It was found that lycopodium, as the most hydrophobic material, effectively influences the membrane performance and structure for membrane distillation applications.

关键词: lycopodium     hydrophobicity     vacuum membrane distillation     desalination    

Novel methods by using non-vacuum insulated tubing to extend the lifetime of the tubing

Chenglong ZHOU,Guojin ZHU,Yongxiang XU,Jifei YU,Xiaoliang ZHANG,Hongzhi SHENG

《能源前沿(英文)》 2015年 第9卷 第2期   页码 142-147 doi: 10.1007/s11708-015-0357-7

摘要: The analysis of the failure mechanics, namely hydrogen permeation of vacuum insulated tubing (VIT), indicated that the failure of VIT could be decreased but could not be avoided. To solve this problem, some measures by using non-vacuum materials were proposed and analyzed in this paper. The results show that to fill the tubing with foam-glass beads or high pressure argon may lead to a good performance.

关键词: vacuum insulated tubing     cyclic steam stimulation     insulation material     thermal conductivity     foam-glass     hydrogen permeation    

高饱和土固结及饱和度对土体固结的影响

金志高

《中国工程科学》 2004年 第6卷 第9期   页码 73-76

摘要:

以Terzaghi土体固结理论和Biot固结理论为基础,按饱和度不同的分类,研究了高饱和土固结机理及过程,深入分析了高饱和土饱和度变化对孔隙流体压缩性的影响,以及由此影响到高饱和土的固结全过程。

关键词: 固结     饱和度     体变模量     压缩    

Toward better understanding vacuum ultraviolet–iodide induced photolysis via hydrogen peroxide formation

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-021-1489-0

摘要:

• UV/VUV/I induces substantial H2O2 and IO3 formation, but UV/I does not.

关键词: Vacuum ultraviolet     Hydrogen peroxide     Iodate     Hydroxyl radical     Redox transition    

高频真空木材干燥的模糊神经网络控制方法研究

姜滨,孙丽萍,曹军,周正

《中国工程科学》 2014年 第16卷 第4期   页码 17-20

摘要:

高频真空木材干燥是一种干燥速度快、能源消耗低、环境污染小的新型联合干燥技术。在木材高频真空联合干燥过程的理论分析基础上,针对神经网络方法建立的木材干燥模型,设计了木材干燥模糊控制器和模糊神经网络控制器。对模糊控制和模糊神经网络两种控制方法进行了仿真实验,结果表明模糊神经网络方法控制效果更好,如温度上升快,控制精度高,稳定性好。模糊神经网络控制方法对实现木材干燥过程的全自动控制具有重要研究意义。

关键词: 高频真空     木材干燥     模糊神经网络    

Enhancement of distillate output of double basin solar still with vacuum tubes

Hitesh N PANCHAL, P K SHAH

《能源前沿(英文)》 2014年 第8卷 第1期   页码 101-109 doi: 10.1007/s11708-014-0299-5

摘要: The latent heat of condensation is lost to the atmosphere; hence it is not utilized to increase distillate output of single basin solar stills. This difficulty was overcome by attaching an additional basin to the main basin. The performance of the double basin solar still was also increased by attaching vacuum tubes to the lower basin; hence the lower basin possessed a higher temperature throughout the day. The latent heat of condensation of the bottom basin was also utilized to increase distillate. But the distillate output of the top basin was even lower compared with that of the bottom basin. This paper proposed a novel approach to increase the distillate output of the double basin solar still attached with vacuum tubes by introducing different sensible energy storage materials like pebbles, black granite gravel and calcium stones to increase the basin area. Experiments were conducted in climate conditions of Mehsana (23.6000° N, 72.4000° E) Gujarat from April to September 2013 with a constant water depth of 2 cm in the top basin with and without the use of basin materials. The results showed that the distillate output of basin material with calcium stones is greater (74%) compared with that of black granite gravel and pebbles. The integration of vacuum tubes with solar still greatly increases the distillate output of the solar still by providing hot water at the lower basin.

关键词: double basin solar still     calcium stones     pebbles     granite gravel     distillate output    

Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Wenpo REN, Honggang CHEN, Chaohe YANG, Honghong SHAN,

《化学科学与工程前沿(英文)》 2010年 第4卷 第3期   页码 250-256 doi: 10.1007/s11705-009-0281-7

摘要: Two kinds of heavy oils were fractionated into eight fractions by Liquid-Solid Adsorption Chromatography, respectively, and samples were collected to measure properties. According to the elemental analysis, molecular weight and H-NMR data, average molecular structures of polycyclic aromatic and heavy resin were constructed with improved Brown-Ladner (B-L) method and several corrections. And then, the most stable conformations of polycyclic aromatic and heavy resin in vacuum and toluene solution were obtained by molecular dynamic simulation, and the molecular size was gotten via the radius of gyration analysis. The results showed that the radius of gyration of polycyclic aromatic and heavy resin was 0.55–0.70 nm in vacuum and 0.60–0.90 nm in toluene solution. With molecular weight increasing, the molecular size in vacuum and toluene solution also increased. Due to the swelling behavior of solvent, the alkyl side chains of heavy oil molecule in solution were more stretched. Thus, the molecular size in toluene solution was larger than that in vacuum.

关键词: dynamic simulation     molecular dynamic     behavior     molecule     Adsorption Chromatography    

低真空管道高速磁悬浮系统技术发展研究

冯仲伟,方兴,李红梅,程爱君,潘永杰

《中国工程科学》 2018年 第20卷 第6期   页码 105-111 doi: 10.15302/J-SSCAE-2018.06.017

摘要:

轮轨式是目前轨道交通技术体系的主流,但由于空气阻力、轮轨黏着、运行噪声等问题的限制,在现有的技术水平下,难以经济地实现运营速度大幅度提高。为满足更高经济运行速度的需求,在利用磁悬浮技术减少轮轨摩擦、振动的基础上,构建低真空运行环境以减小空气阻力和噪声是未来更高速度轨道交通技术发展的重要方向。本文阐述了发展低真空管道高速磁悬浮系统的意义,研究了其技术特点、发展现状,分析了低真空管道高速磁悬浮系统的科学问题和关键技术,并提出了在国家层面立项研究、建设试验线和国家级实验室的政策建议。

关键词: 轨道交通     低真空管道     高速磁悬浮     系统技术    

标题 作者 时间 类型 操作

Lateral displacement of soft ground under vacuum pressure and surcharge load

Chin-Yee ONG, Jin-Chun CHAI

期刊论文

Split-order consolidation optimization for online supermarkets: Process analysis and optimization models

期刊论文

A method for predicting consolidation settlements of floating column improved clayey subsoil

Jinchun CHAI, Supasit PONGSIVASATHIT,

期刊论文

One-dimensional consolidation of over-consolidated soil under time-dependent loading

XIE Kanghe, WANG Kun, CHEN Guohong, HU Anfeng

期刊论文

Numerical study of conduction and radiation heat losses from vacuum annulus in parabolic trough receivers

Dongqiang LEI, Yucong REN, Zhifeng WANG

期刊论文

Dimensionality reduction and prediction of soil consolidation coefficient using random forest coupling

Hai-Bang LY; Huong-Lan Thi VU; Lanh Si HO; Binh Thai PHAM

期刊论文

syndrome and toxic epidermal necrolysis in China: evaluation of risk models and new predictor of pulmonary consolidation

Yanhong Shou, Lu Yang, Yongsheng Yang, Xiaohua Zhu, Feng Li, Bo Yin, Yingyan Zheng, Jinhua Xu

期刊论文

interconnected nano-channels into polyvinylidene fluoride membranes for desalination applications by vacuum

期刊论文

Novel methods by using non-vacuum insulated tubing to extend the lifetime of the tubing

Chenglong ZHOU,Guojin ZHU,Yongxiang XU,Jifei YU,Xiaoliang ZHANG,Hongzhi SHENG

期刊论文

高饱和土固结及饱和度对土体固结的影响

金志高

期刊论文

Toward better understanding vacuum ultraviolet–iodide induced photolysis via hydrogen peroxide formation

期刊论文

高频真空木材干燥的模糊神经网络控制方法研究

姜滨,孙丽萍,曹军,周正

期刊论文

Enhancement of distillate output of double basin solar still with vacuum tubes

Hitesh N PANCHAL, P K SHAH

期刊论文

Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Wenpo REN, Honggang CHEN, Chaohe YANG, Honghong SHAN,

期刊论文

低真空管道高速磁悬浮系统技术发展研究

冯仲伟,方兴,李红梅,程爱君,潘永杰

期刊论文