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A measurement system for thin elastohydrodynamic lubrication films

WANG Xuefeng, GUO Feng, YANG Peiran

《机械工程前沿(英文)》 2007年 第2卷 第2期   页码 193-196 doi: 10.1007/s11465-007-0032-8

摘要: An elastohydrodynamic lubrication (EHL) film measurement system using multi-beam interferometry is introduced in this paper. The measurement principle and the instrumentation are discussed. A simple and efficient method is suggested to obtain the fringe order of measured points. It is demonstrated that the presented measurement system can provide continuous measurement of lubricating films from nano to micro scales at a nano-level resolution, and can be used to investigate ultra-thin EHL films and tiny variations in EHL films.

关键词: instrumentation     continuous measurement     elastohydrodynamic lubrication     ultra-thin     measurement    

Requirements in performance measurement systems of construction projects from the lean production perspective

Karina B. BARTH, Carlos T. FORMOSO

《工程管理前沿(英文)》 2021年 第8卷 第3期   页码 442-455 doi: 10.1007/s42524-020-0108-2

摘要: Performance measurement (PM) generates useful data for process control, facilitates communication between different sectors, and helps to align efforts on the most important aspects of the business. Thus, PM plays a key role in the management of projects and organizations. PM is also important in the implementation of lean production principles and methods, such as reducing the share of nonvalue-adding activities, increasing process transparency, building continuous improvement into the process, and benchmarking. Moreover, the adoption of the lean production philosophy requires changes in PM. Despite its importance, limited studies have been conducted on the use of PM systems for assessing the impact of lean production programs in construction projects. In addition, studies on how lean companies (or projects) use performance measurement and to what extent the indicators adopted reflect the result of actions that have been undertaken are limited. This study proposes a set of requirements in PM systems of construction projects from the perspective of lean production and a taxonomy of performance metrics for lean production systems. Five empirical studies have been carried out on construction companies from South America involved in the implementation of lean production systems. The scope of this investigation is limited to the construction projects as production systems rather than PM at the level of construction organizations.

关键词: performance measurement     lean construction     production management     continuous improvement     metrics    

density measurement for plastic injection molding via ultrasonic technology

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0714-2

摘要: Density variation during the injection molding process directly reflects the state of plastic melt and contains valuable information for process monitoring and optimization. Therefore, in-situ density measurement is of great interest and has significant application value. The existing methods, such as pressure−volume−temperature (PVT) method, have the shortages of time-delay and high cost of sensors. This study is the first to propose an in-situ density measurement method using ultrasonic technology. The analyses of the time-domain and frequency-domain signals are combined in the proposed method. The ultrasonic velocity is obtained from the time-domain signals, and the acoustic impedance is computed through a full-spectral analysis of the frequency-domain signals. Experiments with different process conditions are conducted, including different melt temperature, injection speed, material, and mold structure. Results show that the proposed method has good agreement with the PVT method. The proposed method has the advantages of in-situ measurement, non-destructive, high accuracy, low cost, and is of great application value for the injection molding industry.

关键词: ultrasonic measurement     melt density     in-situ measurement     injection molding    

Strain and process engineering toward continuous industrial fermentation

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1336-1353 doi: 10.1007/s11705-022-2284-6

摘要: Most current biotechnology industries are based on batch or fed-batch fermentation processes, which often show low productivity and high production costs compared to chemical processes. To increase the economic competitiveness of biological processes, continuous fermentation technologies are being developed that offer significant advantages in comparison with batch/fed-batch fermentation processes, including: (1) removal of potential substrates and product inhibition, (2) prolonging the microbial exponential growth phase and enhancing productivity, and (3) avoiding repeated fermentation preparation and lowering operation and installation costs. However, several key challenges should be addressed for the industrial application of continuous fermentation processes, including (1) contamination of the fermentation system, (2) degeneration of strains, and (3) relatively low product titer. In this study, we reviewed and discussed metabolic engineering and synthetic biology strategies to address these issues.

关键词: continuous fermentation     productivity     contamination     strain degeneration     metabolic engineering    

Ant colony optimization in continuous problem

YU Ling, LIU Kang, LI Kaishi

《机械工程前沿(英文)》 2007年 第2卷 第4期   页码 459-462 doi: 10.1007/s11465-007-0079-6

摘要: Based on the analysis of the basic ant colony optimization and optimum problem in a continuous space, an ant colony optimization (ACO) for continuous problem is constructed and discussed. The algorithm is efficient and beneficial to the study of the ant colony optimization in a continuous space.

关键词: beneficial     algorithm     efficient     continuous     ACO    

连续铸钢前沿技术的工程化

干勇

《中国工程科学》 2002年 第4卷 第9期   页码 12-18

摘要:

论述了具有我国自主知识产权的高效连铸和薄板坯连铸工程化关键技术的特点;介绍了连续铸钢领域轻压下、液压非正弦振动、电磁连铸等前沿技术的开发现状;阐述了传统连铸技术超高效率、高品质化及近终形连铸、电磁连铸开发的研发方向。

关键词: 连续铸钢     高效连铸     薄板坯连铸     轻压下     电磁连铸    

Anti-biofouling strategies for implantable biosensors of continuous glucose monitoring systems

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 1866-1878 doi: 10.1007/s11705-023-2340-x

摘要: Continuous glucose monitoring (CGM) systems play an increasingly vital role in the glycemic control of patients with diabetes mellitus. However, the immune responses triggered by the implantation of poorly biocompatible sensors have a significant impact on the accuracy and lifetime of CGM systems. In this review, research efforts over the past few years to mitigate the immune responses by enhancing the anti-biofouling ability of sensors are summarized. This review divided these works into active immune engaging strategy and passive immune escape strategy based on their respective mechanisms. In each strategy, the various biocompatible layers on the biosensor surface, such as drug-releasing membranes, hydrogels, hydrophilic membranes, anti-biofouling membranes based on zwitterionic polymers, and bio-mimicking membranes, are described in detail. This review, therefore, provides researchers working on implantable biosensors for CGM systems with vital information, which is likely to aid in the research and development of novel CGM systems with profound anti-biofouling properties.

关键词: implantable glucose biosensor     anti-biofouling     continuous glucose monitoring     immune responses    

Bending and rotational behaviour of semi-continuous composite beams

WANG Jingfeng, LI Guoqiang

《结构与土木工程前沿(英文)》 2008年 第2卷 第2期   页码 116-122 doi: 10.1007/s11709-008-0015-9

摘要: Stresses and deflections were measured in various semi-continuous composite beams. The bending and rotational capacities of the composite connections were measured in terms of beam curvatures and deflections by using two full-scale semi-rigid composite frames with monotonic loadings. The effect of semi-rigid connections on the performance of composite beams with various loadings was compared with predictions and codes. The tests show that the semi-continuous composite beams are more economic and effective than the simple or continuous composite beams. The semi-rigid connections affect the bending capacities and beam deflections, so the connection behavior should be considered in the design of composite beams. Yielding analysis of the steel beam bottom flange has some influence on the deflection calculation of composite beams.

关键词: rotational     effective     deflection calculation     semi-continuous composite     full-scale semi-rigid    

Seismic performance of fabricated continuous girder bridge with grouting sleeve-prestressed tendon composite

《结构与土木工程前沿(英文)》   页码 827-854 doi: 10.1007/s11709-023-0954-1

摘要: The seismic performance of a fully fabricated bridge is a key factor limiting its application. In this study, a fiber element model of a fabricated concrete pier with grouting sleeve-prestressed tendon composite connections was built and verified. A numerical analysis of three types of continuous girder bridges was conducted with different piers: a cast-in-place reinforced concrete pier, a grouting sleeve-fabricated pier, and a grouting sleeve-prestressed tendon composite fabricated pier. Furthermore, the seismic performance of the composite fabricated pier was investigated. The results show that the OpenSees fiber element model can successfully simulate the hysteresis behavior and failure mode of the grouted sleeve-fabricated pier. Under traditional non-near-fault ground motions, the pier top displacements of the grouting sleeve-fabricated pier and the composite fabricated pier were less than those of the cast-in-place reinforced concrete pier. The composite fabricated pier had a good self-centering capability. In addition, the plastic hinge zones of the grouting sleeve-fabricated pier and the composite fabricated pier shifted to the joint seam and upper edge of the grouting sleeve, respectively. The composite fabricated pier with optimal design parameters has good seismic performance and can be applied in high-intensity seismic areas; however, the influence of pile-soil interaction on its seismic performance should not be ignored.

关键词: seismic performance     continuous girder bridge     grouting sleeve-prestressed tendon composite connections     grouted sleeve connection     design parameters    

Decreasing complexity of glucose time series derived from continuous glucose monitoring is correlated

《医学前沿(英文)》 2023年 第17卷 第1期   页码 68-74 doi: 10.1007/s11684-022-0955-9

摘要: Most information used to evaluate diabetic statuses is collected at a special time-point, such as taking fasting plasma glucose test and providing a limited view of individual’s health and disease risk. As a new parameter for continuously evaluating personal clinical statuses, the newly developed technique “continuous glucose monitoring” (CGM) can characterize glucose dynamics. By calculating the complexity of glucose time series index (CGI) with refined composite multi-scale entropy analysis of the CGM data, the study showed for the first time that the complexity of glucose time series in subjects decreased gradually from normal glucose tolerance to impaired glucose regulation and then to type 2 diabetes (P for trend < 0.01). Furthermore, CGI was significantly associated with various parameters such as insulin sensitivity/secretion (all P < 0.01), and multiple linear stepwise regression showed that the disposition index, which reflects β-cell function after adjusting for insulin sensitivity, was the only independent factor correlated with CGI (P < 0.01). Our findings indicate that the CGI derived from the CGM data may serve as a novel marker to evaluate glucose homeostasis.

关键词: complexity of glucose time series     continuous glucose monitoring     impaired glucose regulation     insulin secretion and sensitivity     refined composite multi-scale entropy    

Analysis of load transfer stability control strategy in hydraulic synchronized continuous slippage

LIU Yan-bo, WU Jian-zhong, ZHANG Xuan

《机械工程前沿(英文)》 2006年 第1卷 第2期   页码 222-226 doi: 10.1007/s11465-006-0007-1

摘要: Hydraulic synchronized continuous slippage technique, which integrates mechanical, electrical and hydraulic control, is introduced in this paper for the practical requirements of some construction projects. The core of this technique (the stability of the load transfer) is illustrated in detail. Three speed control strategies to transfer the load excessive, lower and same speed are presented to accomplish the smoothness and stability in the process of slippage. An optimization of the speed control strategy (same speed) is deduced from the modeling analysis and its validity and maneuverability are tested by practical application, which provides evidence for similar engineering in theory and practice.

关键词: excessive     slippage technique     optimization     continuous slippage     engineering    

Non-invasive continuous blood pressure monitoring: a review of current applications

null

《医学前沿(英文)》 2013年 第7卷 第1期   页码 91-101 doi: 10.1007/s11684-013-0239-5

摘要:

Blood pressure monitoring has come a long way from the initial observations made by Reverend Hales in the 18th century. There are none that deny the importance of monitoring perioperative blood pressure; however, the limited ability of the current prevalent technology (oscillometric blood pressure monitoring) to offer continuous blood pressure measurements leaves room for improvement. Invasive monitoring is able to detect beat-to-beat blood pressure measurement, but the risks inherent to the procedure make it unsuitable for routine use except when this risk is outweighed by the benefits. This review focuses on the discoveries which have led up to the current blood pressure monitoring technologies, and especially the creation of those offering non-invasive but continuous blood pressure monitoring capabilities, including their methods of measurement and limitations.

关键词: non-invasive blood pressure monitoring     continuous blood pressure monitoring     invasive blood pressure monitoring     Riva-Rocci technique     oscillometric     Pe?áz technique     arterial tonometry     pulse transit time    

Removal of dyes from wastewater by growing fungal pellets in a semi-continuous mode

Tao Lu, Qilei Zhang, Shanjing Yao

《化学科学与工程前沿(英文)》 2017年 第11卷 第3期   页码 338-345 doi: 10.1007/s11705-017-1644-0

摘要: To increase the efficiency of dye removal from wastewater using mycelial pellets, a bubble column reactor with a simple structure was designed and efficiently used to remove dyes from solution containing dyes. The mycelial pellets were prepared by marine fungus ZJUBE-1. Eight dyes were tested as dye targets for the adsorption capacity of mycelial pellets and good removal results were obtained. Eriochrome black T was selected as a model dye for characterizing the adsorption processes in detail. The measurement results of Zeta potential and FT-IR analysis indicate that the electrostatic attraction may play a key role in the biosorption process. The bubble column reactor was utilized to study the batch dye-removal efficiency of mycelial pellets. A re-culture process between every two batches, which was under non-sterile condition, successfully enhanced the utilization of mycelium biomass. The dye removal rate is 96.4% after 12 h in the first batch and then decreases slowly in the following batches. This semi-continuous mode, which consists of commutative processes of dye-removal and re-culture, has some outstanding advantages, such as low power consumption, easy operation, high dye removal rate, and efficient biomass utilization.

关键词: dye     mycelial pellets     marine fungus     bubble column reactor     semi-continuous biosorption    

A continuous/discontinuous deformation analysis (CDDA) method based on deformable blocks for fracture

Yongchang CAI, Hehua ZHU, Xiaoying ZHUANG

《结构与土木工程前沿(英文)》 2013年 第7卷 第4期   页码 369-378 doi: 10.1007/s11709-013-0222-x

摘要: In the framework of finite element meshes, a novel continuous/discontinuous deformation analysis (CDDA) method is proposed in this paper for modeling of crack problems. In the present CDDA, simple polynomial interpolations are defined at the deformable block elements, and a link element is employed to connect the adjacent block elements. The CDDA is particularly suitable for modeling the fracture propagation because the switch from continuous deformation analysis to discontinuous deformation analysis is natural and convenient without additional procedures. The SIFs (stress intensity factors) for various types of cracks, such as kinked cracks or curved cracks, can be easily computed in the CDDA by using the virtual crack extension technique (VCET). Both the formulation and implementation of the VCET in CDDA are simple and straightforward. Numerical examples indicate that the present CDDA can obtain high accuracy in SIF results with simple polynomial interpolations and insensitive to mesh sizes, and can automatically simulate the crack propagation without degrading accuracy.

关键词: fracture     crack     propagation     deformable block     continuous/discontinuous deformation analysis (CDDA)    

Independent continuous and mapping method of structural topology optimization based on the global stress

Yunkang SUI, Jili FENG, Hongling YE, Xirong PENG,

《机械工程前沿(英文)》 2010年 第5卷 第2期   页码 130-142 doi: 10.1007/s11465-010-0011-3

摘要: There are three difficulties in topology optimization of continuum structures. 1) The topology under multiple load case is more difficult to be optimized than under single load case, because the former becomes a multiple objective based on compliance objective functions. 2) With local constraints, such as an elemental stress limit, the topology is more difficult to be solved than with global constraints, such as the displacement or frequency limits, because the sensitivity analysis of the former has very expensive computation. 3) With the phenomenon of load illness, which is similar with stiffness illness in the structural analysis, it is not easy to get the reasonable final topological structure, because it is difficult to consider different influences between the loads with small forces and big forces, and some topology paths of transferring small forces may disappear during the iteration process. To overcome difficulties above, four measures are adopted. 1) Topology optimization model is established by independent continuous mapping (ICM) method. 2) Based on the von Mises strength theory, all elements’ stress constraints are transformed into a structural energy constraint. 3) The phenomenon of load illness is divided to classify into three cases. 4) A strategy based on strain energy is proposed to adopt ICM method with stress globalization, and the problems of the above mentioned three cases of load illness are solved in terms of different complementary approaches. Several numerical examples show that the topology path of transferring forces can be obtained more easily by substituting global strain energy constraints for local stresses constraints, and the problem of load illness can be solved well by the weighting method that takes the structural energy as a weighting coefficient.

关键词: independent continuous mapping (ICM) method     global stresses constraints     topology optimization     continuum structure     load illness    

标题 作者 时间 类型 操作

A measurement system for thin elastohydrodynamic lubrication films

WANG Xuefeng, GUO Feng, YANG Peiran

期刊论文

Requirements in performance measurement systems of construction projects from the lean production perspective

Karina B. BARTH, Carlos T. FORMOSO

期刊论文

density measurement for plastic injection molding via ultrasonic technology

期刊论文

Strain and process engineering toward continuous industrial fermentation

期刊论文

Ant colony optimization in continuous problem

YU Ling, LIU Kang, LI Kaishi

期刊论文

连续铸钢前沿技术的工程化

干勇

期刊论文

Anti-biofouling strategies for implantable biosensors of continuous glucose monitoring systems

期刊论文

Bending and rotational behaviour of semi-continuous composite beams

WANG Jingfeng, LI Guoqiang

期刊论文

Seismic performance of fabricated continuous girder bridge with grouting sleeve-prestressed tendon composite

期刊论文

Decreasing complexity of glucose time series derived from continuous glucose monitoring is correlated

期刊论文

Analysis of load transfer stability control strategy in hydraulic synchronized continuous slippage

LIU Yan-bo, WU Jian-zhong, ZHANG Xuan

期刊论文

Non-invasive continuous blood pressure monitoring: a review of current applications

null

期刊论文

Removal of dyes from wastewater by growing fungal pellets in a semi-continuous mode

Tao Lu, Qilei Zhang, Shanjing Yao

期刊论文

A continuous/discontinuous deformation analysis (CDDA) method based on deformable blocks for fracture

Yongchang CAI, Hehua ZHU, Xiaoying ZHUANG

期刊论文

Independent continuous and mapping method of structural topology optimization based on the global stress

Yunkang SUI, Jili FENG, Hongling YE, Xirong PENG,

期刊论文