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Nonlinear design-point performance adaptation approaches and their comparisons for gas turbine applications

Y. G. LI, P. PILIDIS,

《能源前沿（英文）》 2009年 第3卷 第4期   页码 446-455 doi: 10.1007/s11708-009-0042-9

摘要： Accurate performance simulation and understanding of gas turbine engines is very useful for gas turbine manufacturers and users alike and such a simulation normally starts from its design point. When some of the engine component parameters for an existing engine are not available, they must be estimated in order that the performance analysis can be started. Therefore, the simulated design point performance of an engine may be slightly different from its actual performance. In this paper, two nonlinear gas turbine design-point performance adaptation approaches have been presented to best estimate the unknown component parameters and match available design point engine performance, one using a nonlinear matrix inverse adaptation method and the other using a Genetic Algorithm-based adaptation approach. The advantages and disadvantages of the two adaptation methods have been compared with each other. In the approaches, the component parameters may be compressor pressure ratios and efficiencies, turbine entry temperature, turbine efficiencies, engine mass flow rate, cooling flows, and by-pass ratio, etc. The engine performance parameters may be thrust and SFC for aero engines, shaft power, and thermal efficiency for industrial engines, gas path pressures, temperatures, etc. To select the most appropriate to-be-adapted component parameters, a sensitivity bar chart is used to analyze the sensitivity of all potential component parameters against the engine performance parameters. The two adaptation approaches have been applied to a model gas turbine engine. The application shows that the sensitivity bar chart is very useful in the selection of the to-be-adapted component parameters, and both adaptation approaches are able to produce good quality engine models at design point. The comparison of the two adaptation methods shows that the nonlinear matrix inverse method is faster and more accurate, while the genetic algorithm-based adaptation method is more robust but slower. Theoretically, both adaptation methods can be extended to other gas turbine engine performance modelling applications.

关键词： gas turbine     engine     performance adaptation     performance matching     design-point performance simulation     influence coefficient matrix     genetic algorithm    

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Influence of temperature on cam-tappet lubrication in an internal combustion engine

CHANG Qiuying, YANG Peiran, WANG Jing, CHEN Quanshi

《机械工程前沿（英文）》 2007年 第2卷 第4期   页码 489-492 doi: 10.1007/s11465-007-0085-8

摘要： The transient thermo-elastohydrodynamic (TEHL) lubrication simulation and isothermal elastohydrodynamic (EHL) simulation were performed on the exhausting cam-tappet friction pair of an internal combustion engine. Although by employing the two models the center pressure, the thickness of the lubricant film and friction coefficient obtained were similar in the changing trend during a rotating cycle, the parameters make a great difference, especially for the thickness of the lubricant film; the TEHL was four times thicker than the EHL. These results show that the temperature should not be neglected in the study of the lubrication of cam-tappet pairs.

关键词： coefficient     combustion     isothermal elastohydrodynamic     temperature     thickness    

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Influence of surface modified mixed metal oxide nanoparticles on the electrochemical and mechanical propertiesof polyurethane matrix

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 1-14 doi: 10.1007/s11705-022-2176-9

摘要： Newly synthesized functional nanoparticles, 3-amino-1,2,4-triazole (ATA)/SiO2–TiO2 were introduced to the polyurethane (PU) matrix. Electrochemical techniques were used to investigate the barrier properties of the synthesized PU–ATA/SiO2–TiO2 nanocomposite coated steel specimen. In natural seawater, electrochemical impedance spectroscopy experiments indicated outstanding protective behaviour for the PU–ATA/SiO2–TiO2 coated steel. The coating resistance (Rcoat) of PU–ATA/SiO2–TiO2 was determined to be 2956.90 kΩ·cm–2. The Rcoat of the PU–ATA/SiO2–TiO2 nanocomposite coating was found to be over 50% higher than the PU coating. The current measured along the scratched surface of the PU–ATA/SiO2–TiO2 coating was found to be very low (1.65 nA). The enhanced ATA/SiO2–TiO2 nanoparticles inhibited the entry of electrolytes into the coating interface, as revealed by scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray diffraction analysis of the degradation products. Water contact angle testing validated the hydrophobic nature of the PU–ATA/SiO2–TiO2 coating (θ = 115.4°). When the concentration of ATA/SiO2−TiO2 nanoparticles was 2 wt %, dynamic mechanical analysis revealed better mechanical properties. Therefore, the newly synthesised PU–ATA/SiO2–TiO2 nanocomposite provided excellent barrier and mechanical properties due to the addition of ATA/SiO2–TiO2 nanoparticles to the polyurethane, which inhibited material degradation and aided in the prolongation of the coated steel’s life.

关键词： SiO2/TiO2 nanoparticle     nanocomposite coatings     dynamic mechanical analysis     electrochemical techniques     corrosion     colloids and interfaces    

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Influence of initial curing conditions and exposure environments on chloride migration in concrete using

Wen XUE, Weiliang JIN, Hiroshi YOKOTA,

《结构与土木工程前沿（英文）》 2010年 第4卷 第3期   页码 348-353 doi: 10.1007/s11709-010-0077-3

摘要： To investigate the influence of initial curing conditions and exposure environments on chloride ions’ migration in concrete, the specimens that were cured in different conditions and placed in several marine environments were studied. The amount of chloride ions passing through the specimen’s section was monitored in the accelerated chloride migration test. The effective chloride diffusion coefficients () were calculated from the steady-state on the basis of Nernst-Planck’s equation. The results indicated that the initial curing conditions and the wet-dry interval of external environments have coupling influence on effective diffusion coefficient of chloride ion significantly. reflected the density and pore connectivity of concrete. The co-effects of the initial curing condition and following exposure environment should be taken into account in durability design for concrete structure located in marine environment.

关键词： durability     effective diffusion coefficient     steady-state     migration test    

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Balancing method without trial weights for rotor systems based on similitude scale model

Ruiduo YE, Liping WANG, Xiaojie HOU, Zhong LUO, Qingkai HAN

《机械工程前沿（英文）》 2018年 第13卷 第4期   页码 571-580 doi: 10.1007/s11465-018-0478-x

摘要：

A balancing method without trial weights based on the dynamic similitude scale model was proposed as a solution to the balancing problem of a large-scale rotor system. This method could be used to directly obtain the required coefficients for the balancing problem of the prototype system through a similarity model test without a prototype test. Thus, the weight test process of the prototype system was effectively eliminated in the proposed balancing method. First, with the rotor system as the research object, the analytical expression of the influence coefficient was derived on the basis of rotor dynamics theory. Then, through calculation and dimensional analysis methods, the similitude relationships of the rotor system and the influence coefficient were deduced on the basis of dynamic similitude theory. The correctness of the proposed similitude relationships was verified through numerical simulation and experiment. The balancing method without trial weights was proposed based on the similitude relationship of the influence coefficient. The effect of the balancing method without trial weights was compared with that of the traditional influence coefficient method through numerical simulation, and the results verified the correctness and effectiveness of the proposed balancing method. The results of this study provide theoretical supplements for the balancing method and the similitude design of the rotor system.

关键词： rotor system     dynamic similitude     balancing     without trial weights     influence coefficient    

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Decellularized extracellular matrix mediates tissue construction and regeneration

《医学前沿（英文）》 2022年 第16卷 第1期   页码 56-82 doi: 10.1007/s11684-021-0900-3

摘要： Contributing to organ formation and tissue regeneration, extracellular matrix (ECM) constituents provide tissue with three-dimensional (3D) structural integrity and cellular-function regulation. Containing the crucial traits of the cellular microenvironment, ECM substitutes mediate cell–matrix interactions to prompt stem-cell proliferation and differentiation for 3D organoid construction in vitro or tissue regeneration in vivo. However, these ECMs are often applied generically and have yet to be extensively developed for specific cell types in 3D cultures. Cultured cells also produce rich ECM, particularly stromal cells. Cellular ECM improves 3D culture development in vitro and tissue remodeling during wound healing after implantation into the host as well. Gaining better insight into ECM derived from either tissue or cells that regulate 3D tissue reconstruction or organ regeneration helps us to select, produce, and implant the most suitable ECM and thus promote 3D organoid culture and tissue remodeling for in vivo regeneration. Overall, the decellularization methodologies and tissue/cell-derived ECM as scaffolds or cellular-growth supplements used in cell propagation and differentiation for 3D tissue culture in vitro are discussed. Moreover, current preclinical applications by which ECM components modulate the wound-healing process are reviewed.

关键词： decellularized extracellular matrix     3D culture     organoids     tissue repair    

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Perspective of mixed matrix membranes for carbon capture

Shinji Kanehashi, Colin A. Scholes

《化学科学与工程前沿（英文）》 2020年 第14卷 第3期   页码 460-469 doi: 10.1007/s11705-019-1881-5

摘要： Polymeric membrane-based gas separation has found wide applications in industry, such as carbon capture, hydrogen recovery, natural gas sweetening, as well as oxygen enrichment. Commercial gas separation membranes are required to have high gas permeability and selectivity, while being cost-effective to process. Mixed matrix membranes (MMMs) have a composite structure that consists of polymers and fillers, therefore featuring the advantages of both materials. Much effort has been made to improve the gas separation performance of MMMs as well as general membrane properties, such as mechanical strength and thermal stability. This perspective describes potential use of MMMs for carbon capture applications, explores their limitations in fabrication and methods to overcome them, and addresses their performance under industry gas conditions.

关键词： membranes     polymeric     mixed matrix     impurities    

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RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2161-2161 doi: 10.1007/s11705-009-0143-3

摘要： RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

关键词： tee junction     Momentum exchange coefficient     RETRACTED    

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Strengthening of reinforced concrete beams using fiber-reinforced cementitious matrix systems fabricated

《结构与土木工程前沿（英文）》   页码 1100-1116 doi: 10.1007/s11709-023-0967-9

摘要： The performance of a new fiber-reinforced cementitious matrix (FRCM) system developed using custom-designed mortar and fabrics is investigated in this study. The behavior of this system is evaluated in terms of both the flexural and shear strengthening of reinforced concrete beams. Eight beams are designed to assess the effectiveness of the FRCM system in terms of flexural strengthening, and four specimens are designed to investigate their shear behavior. The parameters investigated for flexural strengthening are the number of layers, span/depth ratio, and the strengthening method. Unlike previous studies, custom fabrics with similar axial stiffness are used in all strengthening methods in this study. In the shear-strengthened specimens, the effects of the span/depth ratio and strengthening system type (fiber-reinforced polymer (FRP) or FRCM) are investigated. The proposed FRCM system exhibits desirable flexural and shear strengthening for enhancing the load capacity, provides sufficient bonding with the substrate, and prevents premature failure modes. Considering the similar axial stiffness of fabrics used in both FRCM and FRP systems and the higher load capacity of specimens strengthened by the former, cement-based mortar performs better than epoxy.

关键词： fiber-reinforced cementitious matrix     flexural strengthening     shear strengthening     carbon fiber-reinforced polymer     shear span    

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Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

《能源前沿（英文）》 2014年 第8卷 第2期   页码 160-172 doi: 10.1007/s11708-014-0321-y

摘要： This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions.

关键词： Nusselt number     flow rate     heat transfer     heat transfer coefficient     thermal efficiency     forced convection    

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A dynamic model of mobile concrete pump boom based on discrete time transfer matrix method

Wu REN, Yunxin WU, Zhaowei ZHANG

《机械工程前沿（英文）》 2013年 第8卷 第4期   页码 360-366 doi: 10.1007/s11465-013-0280-8

摘要：

Mobile concrete pump boom is typical multi-body large-scale motion manipulator. Due to posture constantly change in working process, kinematic rule and dynamic characteristic are difficult to solve. A dynamics model of a mobile concrete pump boom is established based on discrete time transfer matrix method (DTTMM). The boom system is divided into sub-structure A and sub-structure B. Sub-structure A is composed by the 1st boom and hydraulic actuator as well as the support. And sub-structure B is consists of the other three booms and corresponding hydraulic actuators. In the model, the booms and links are regarded as rigid elements and the hydraulic cylinders are equivalent to spring-damper. The booms are driven by the controllable hydraulic actuators. The overall dynamic equation and transfer matrix of the model can be assembled by sub-structures A and B. To get a precise result, step size and integration parameters are studied then. Next the tip displacement is calculated and compared with the result of ADAMS software. The displacement and rotation angle curves of the proposed method fit well with the ADAMS model. Besides it is convenient in modeling and saves time. So it is suitable for mobile concrete pump boom real-time monitoring and dynamic analysis. All of these provide reference to boom optimize and engineering application of such mechanisms.

关键词： multi-body     mobile concrete pump boom     discrete time transfer matrix method (DTTMM)     kinematic     dynamic     tip displacement    

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Glycosylation of dentin matrix protein 1 is critical for fracture healing via promoting chondrogenesis

Hui Xue, Dike Tao, Yuteng Weng, Qiqi Fan, Shuang Zhou, Ruilin Zhang, Han Zhang, Rui Yue, Xiaogang Wang, Zuolin Wang, Yao Sun

《医学前沿（英文）》 2019年 第13卷 第5期   页码 575-589 doi: 10.1007/s11684-019-0693-9

摘要： Fractures are frequently occurring diseases that endanger human health. Crucial to fracture healing is cartilage formation, which provides a bone-regeneration environment. Cartilage consists of both chondrocytes and extracellular matrix (ECM). The ECM of cartilage includes collagens and various types of proteoglycans (PGs), which play important roles in maintaining primary stability in fracture healing. The PG form of dentin matrix protein 1 (DMP1-PG) is involved in maintaining the health of articular cartilage and bone. Our previous data have shown that DMP1-PG is richly expressed in the cartilaginous calluses of fracture sites. However, the possible significant role of DMP1-PG in chondrogenesis and fracture healing is unknown. To further detect the potential role of DMP1-PG in fracture repair, we established a mouse fracture model by using a glycosylation site mutant DMP1 mouse (S89G-DMP1 mouse). Upon inspection, fewer cartilaginous calluses and down-regulated expression levels of chondrogenesis genes were observed in the fracture sites of S89G-DMP1 mice. Given the deficiency of DMP1-PG, the impaired IL-6/JAK/STAT signaling pathway was observed to affect the chondrogenesis of fracture healing. Overall, these results suggest that DMP1-PG is an indispensable proteoglycan in chondrogenesis during fracture healing.

关键词： fracture     extracellular matrix     dentin matrix protein 1     proteoglycan     cartilage    

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A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

《环境科学与工程前沿（英文）》 2016年 第10卷 第3期   页码 428-437 doi: 10.1007/s11783-015-0780-3

摘要： UV photolysis and UV based advanced oxidation processes (AOPs) are gaining more and more attention for drinking water treatment. Quantum yield ( ) and molar absorption coefficient ( ) are the two critical parameters measuring the effectiveness of photolysis of a compound. The product of the two was proposed as a fundamental measure of a constituent’s amenability to transformation by photolysis. It was shown that this product, named the photolysis coefficient, , can be determined using standard bench tests and captures the properties that govern a constituent’s transformation when exposed to light. The development showed the photolysis coefficient to be equally useful for microbiological, inorganic and organic constituents. Values of calculated by the authors based on quantum yield and molar absorption coefficient data from the literature were summarized. Photolysis coefficients among microorganisms ranged from 8500 to more than 600000 and are far higher than for inorganic and organic compounds, which varied over a range of approximately 10 to 1000 and are much less sensitive to UV photolysis than the microorganisms.

关键词： UV photolysis     disinfection     advanced oxidation     N-nitrosodimethylamine     quantum yield     absorption coefficient    

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Role of salivary matrix metalloproteinase-8 (MMP-8) in chronic periodontitis diagnosis

null

《医学前沿（英文）》 2015年 第9卷 第1期   页码 72-76 doi: 10.1007/s11684-014-0347-x

摘要：

Periodontitis is an inflammatory disease of the periodontium. Any imbalance between the matrix metalloproteinases (MMPs) secreted by neutrophils and tissue inhibitors initiates the destruction of collagen in gum tissue, leading to chronic periodontitis. This study aimed to correlate salivary levels of MMP-8 and periodontal parameters of chronic periodontitis to establish MMP-8 as a noninvasive marker for the early diagnosis of chronic periodontitis. The study involved 40 subjects visiting the periodontic OPD of Dr. Ziauddin Ahmad Dental College and Hospital, located in Aligarh, U.P., India, from 2011 to 2012. The subjects were divided into two groups: group I consisted of 20 periodontally healthy subjects (controls) while group II consisted of 20 patients with chronic periodontitis. Chronic periodontitis was assessed on the basis of several periodontal parameters, including pocket probing depth (PPD), clinical attachment level (CAL), gingival index (GI), and plaque index (PI). Around 3 ml of unstimulated and whole expectorated saliva was collected for MMP-8 estimation by ELISA using Quantikine human total MMP-8 immunoassay kits. Data were analyzed using STATISTICA (Windows version 6) software. Salivary MMP-8 levels of groups I and II were 190.91±143.89 ng/ml and 348.26±202.1 ng/ml, respectively. The MMP-8 levels and periodontal status (PPD, CAL, GI, and PI) of groups I and II showed positive and significant correlations (for PPD, r = 0.63, P<0.001; for CAL, r = 0.54, P<0.001; for GI, r = 0.49, P<0.001; and for PI, r = 0.63, P<0.001). The results of this study demonstrate elevated concentrations of MMP-8 in individuals with chronic periodontitis.

关键词： matrix metalloproteinase-8     chronic periodontitis     pocket probing depth     clinical attachment level     gingival index     plaque index    

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Effect of heat transfer coefficient of steam turbine rotor on thermal stress field under off-design condition

Jie GUO,Danmei XIE,Hengliang ZHANG,Wei JIANG,Yan ZHOU

《能源前沿（英文）》 2016年 第10卷 第1期   页码 57-64 doi: 10.1007/s11708-015-0385-3

摘要： The precise calculation of temperature and thermal stress field of steam turbine rotor under off-design conditions is of paramount significance for safe and economic operation, in which an accurate calculation of heat transfer (HT) coefficient plays a decisive role. HT coefficient changes dramatically along with working conditions. First, a finite element analysis of rotor model, applied with ordinary rotor materials, has been conducted to investigate the temperature and thermal stress difference along with the change of HT coefficient from 20 W/(m ·°C) to 20000 W/(m ·°C). Next, the differentiation between existing empirical formulas has been analyzed from the aspect of physical significance of non-dimension parameters. Finally, a verifying case of the cold startup of a 1000MW unit has been proceeded. The result shows that the accuracy of coefficient calculation when steam parameters are low has a greater influence on that of rotor temperature and thermal stress, which means a precise empirical HT coefficient formula, like the Sarkar formula is strongly recommended. When steam parameters are high and HT coefficient is larger than 10 W/(m ·°C), there will be barely any influence on the calculation of thermal stress. This research plays a constructive role in the calculation and analysis of thermal stress.

关键词： steam turbine     rotor     thermal stress     heat transfer coefficient     empirical formula    

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标题 作者 时间 类型 操作

Nonlinear design-point performance adaptation approaches and their comparisons for gas turbine applications

Y. G. LI, P. PILIDIS,

期刊论文

Influence of temperature on cam-tappet lubrication in an internal combustion engine

CHANG Qiuying, YANG Peiran, WANG Jing, CHEN Quanshi

期刊论文

Influence of surface modified mixed metal oxide nanoparticles on the electrochemical and mechanical propertiesof polyurethane matrix

期刊论文

Influence of initial curing conditions and exposure environments on chloride migration in concrete using

Wen XUE, Weiliang JIN, Hiroshi YOKOTA,

期刊论文

Balancing method without trial weights for rotor systems based on similitude scale model

Ruiduo YE, Liping WANG, Xiaojie HOU, Zhong LUO, Qingkai HAN

期刊论文

Decellularized extracellular matrix mediates tissue construction and regeneration

期刊论文

Perspective of mixed matrix membranes for carbon capture

Shinji Kanehashi, Colin A. Scholes

期刊论文

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

期刊论文

Strengthening of reinforced concrete beams using fiber-reinforced cementitious matrix systems fabricated

期刊论文

Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

期刊论文

A dynamic model of mobile concrete pump boom based on discrete time transfer matrix method

Wu REN, Yunxin WU, Zhaowei ZHANG

期刊论文

Glycosylation of dentin matrix protein 1 is critical for fracture healing via promoting chondrogenesis

Hui Xue, Dike Tao, Yuteng Weng, Qiqi Fan, Shuang Zhou, Ruilin Zhang, Han Zhang, Rui Yue, Xiaogang Wang, Zuolin Wang, Yao Sun

期刊论文

A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

期刊论文

Role of salivary matrix metalloproteinase-8 (MMP-8) in chronic periodontitis diagnosis

null

期刊论文

Effect of heat transfer coefficient of steam turbine rotor on thermal stress field under off-design condition

Jie GUO,Danmei XIE,Hengliang ZHANG,Wei JIANG,Yan ZHOU

期刊论文