天然海水中15CDV6/MDN138及15CDV6/MDN250合金的电流相互作用（英文）

The galvanic corrosion behavior of the metal combinations 15 CDV6/MDN138 and 15 CDV6/MDN250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI's Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN138, MDN250, and 15 CDV6 of the individual metal, the galvanic potential and galvanic current of the couples 15 CDV6/MDN138 and 15 CDV6/MDN250, were periodically monitored throughout the study period. The calcareous deposits on MDN138 and MDN250 in galvanic contact with 15 CDV6 were analyzed using XRD. The electrochemical behavior of MDN138, MDN250, and 15 CDV6 in seawater was studied using an electrochemical work station. The surface characteristics of MDN138 and MDN250 in galvanic contact with 15 CDV6 have been examined with a scanning electron microscope. The results of the study reveal that the galvanic protection offered by15 CDV6 to MDN250 and MDN138 in natural seawater amounts to 93% and 98%, respectively, implying that the galvanic protection offered by 15 CDV6 is continuous and effective, which has been further evinced from the adherent nature of the calcareous deposit film comprising compounds such as CaCO_3(calcite, aragonite, and vaterite), MgCO_3(magnesite),Mg(OH)_2(brucite), and MgO(brucite).     

Frequency-based transit assignment considering seat capacities

This paper proposes a frequency-based assignment model that considers travellers probability of finding a seat in their perception of route cost and hence also their route choice. The model introduces a “fail-to-sit” probability at boarding points with travel costs based on the likelihood of travelling seated or standing. Priority rules are considered; in particular it is assumed that standing on-board passengers will occupy any available seats of alighting passengers before newly boarding passengers can fill any remaining seats. At the boarding point passengers are assumed to mingle, meaning that FIFO is not observed, as is the case for many crowded bus and metro stops, particularly in European countries. The route choice considers the common lines problem and an user equilibrium solution is sought through a Markov type network loading process and the method of successive averages. The model is first illustrated with a small example network before being applied to the inner zone of London’s underground network. The effect of different values passengers might attach to finding a seat are illustrated. Applications of the model for transit planning as well as for information provision at the journey planner stage are discussed.     

Use of GIS-Based Models for Integrating and Developing Marine Fish Cages within the Tourism Industry in Tenerife (Canary Islands)

Site selection is a key factor in any aquaculture operation, affecting both success and sustainability. Moreover, it can solve conflicts between different coastal activities, making a rational use of the coastal space. Geographical information systems (GIS) have become of increased significance for environmental planning and assessment mainly because of the need to compare a great number of spatially related data, and because it can be used to couple these spatial data with their attributes and overlay them. This study used GIS and related technology to build a spatial database using those criteria which were considered to have any influence in integrating marine fish-cage culture within the tourism industry in Tenerife. Criteria were grouped in three submodels (distance to beaches, nautical sports, and viewshed), which were combined to generate a final output showing the most suitable areas for cage culture development in coexistence with tourism. Most areas of the coastline of Tenerife were identified as being suitable (56%) or very suitable (46%), suggesting that marine cage aquaculture could be developed on the island in coexistence with the well-established tourism industry.     

Experimental research of the EQ6110HEV hybrid electric bus using an on-line debugging system

This paper describes the on-line debugging software developed by our research team. The software has five functions and can be helpful in achieving rapid development for hybrid electric buses. In addition, the software can monitor system states continuously and also modify parametric maps or update control programs using its on-line programming function. Based on the on-line debugging system, the hybrid propulsion control system is designed, and all the working modes of the hybrid electric bus are tested. Finally, experiments are carried out that verify that the debugging system is feasible and reliable. The test results show that the hybrid electric bus can reduce fuel consumption by about 19.1 percent, in comparison with conventional buses.     

电流变流体的润滑性能研究

提出了电流变流体作为润滑剂使用的新设想,研究了电流变流体粘度的可控特性,通过试验获得了电流变流体摩擦力随电场强度、悬浮颗粒浓度、油膜厚度等因素的变化规律,为深入研究电流变流体的润滑特性奠定了基础。     

RECENT DEVELOPMENT OF PROCESS SIMULATION AND ITS APPLICATIONS TO MANUFACTURING PROCESSES

l.IntroductionThemostboortantdrivingforceinmanufacturillistoPrOduCeabetterPrOductatalowercost.GenerallyeffecthemethodsinchideshOrtenintheleadtiminthedesigncyCle,andredUcinthetoolingcostandmaChinedOWnmeatProductionst4e.AllOfthemrewtabettertmderstandingofhO…     

Numerical simulation on truncated oval-nosed projectile penetrating into stiffened plate北大核心CSCD

[Objectives]In this paper, the numerical simulation method is used to study the anti-penetration performance and energy absorption mode of a stiffened plate, as well as the influence of different stiffened bars on the flight attitude of the projectile body.[Methods] Finite element software LS-DYNA is used to simulate the process of a truncated oval-nosed projectile penetrating a stiffened plate, and the results of the numerical simulation are compared with an experiment to verify the reliability of the numerical simulation method. The momentum method and mass equivalence method are used to predict the residual velocity of the projectile, and the applicability of different theoretical methods within different velocity ranges is compared. The deformation energy of different regions of the stiffened plate is then extracted to analyze the influence of the initial velocity of the projectile body on the energy absorption mode of the target plate. Finally, the structure of the stiffeners is changed and the influence of the relative position of the stiffeners on the penetration attitude of the projectile body is analyzed.[Results]The results show that the mass equivalence method is more accurate than the momentum method in predicting the residual velocity of the stiffened plate when the initial velocity of the projectile body is in the range of 300–900 m/s. The ratio of the deformation energy of the stiffened plate to the energy loss of the projectile body decreases with the increase of the initial velocity of the projectile body. The effect of a T-stiffened plate on trajectory is greater than that of a rectangular-stiffened plate.[Conclusions]The related calculation method and research results have certain reference value for research and engineering application surrounding the anti-penetration of stiffened plates. © 2023 Chinese Journal of Ship Research. All rights reserved.     

襄阳汉江沉管隧道设计关键技术北大核心CSCD

基于襄阳汉江沉管隧道的工程设计实践,针对该隧道强冲刷、强透水地层深厚、防洪要求高等特点,对隧道平纵布置、管节及接头止水结构、干坞选型及结构、沉管基础及回填、沉管最终接头及对接端止水结构等进行了研究。结果表明:(1)内河沉管隧道采用长距离双轴线干坞布置方式,通过格形地下连续墙、超深落底式帷幕、地下连续墙预应力锚索垂直支护和混凝土封底组合技术解决了强透水地层深基坑支护及隔水难题;(2)采用全断面顺浇技术进行整体式管节预制,实现了管节接头止水设施的全国产化;(3)在内河沉管隧道采用高精度浮式整平先铺卵石基础,并提出了强冲刷区管顶防冲保护解决方案;(4)采用了不设独立止推构造的陆域最终接头,并针对工程需求设置了大直径锁口钢管桩配合外侧止水墙的对接端支护结构及分片整体吊装双壁钢围堰二次止水结构。     

Aspects of the stability of jack-up spud-can foundations

A three-level procedure for assessing jack-up foundation stability for more or less homogenous soils is described. The objective is to provide a rational framework for these assessments that ensures their safe operation in extended year-round operations and enables their use in deeper waters than at present.

The three levels of the procedure have to be entered successively as long as foundation stability cannot be proven. The first level is a screening exercise and essentially replaces the well-known preload check. The second level compares factored foundation loads resulting from a structural analysis with foundation capacities obtained with ultimate bearing capacity formulae. The most refined third level assesses whether the displacements associated with these loads lead to an acceptable situation, i.e. capacity increase and/or load redistribution that does not result in collapse of the jack-up unit.

Since, for maximum benefit, this third-stage analysis requires a non-linear foundation model to be linked with the structural package used: such a tool is provided in the paper. Examples are given to demonstrate the impact of the assessment procedure.

This procedure forms part of the overall in-house approach to the assessment of jack-ups and has already been offered to the jack-up industry as part of the continuing efforts towards establishing common and accepted standards for jack-up assessments. Further developments have been identified and will be pursued.     

A repeated cross-sectional evaluation of car ownership

This paper studies changes in the relationship between household car ownership and income by household type. Ordered response probit models of car ownership are estimated for a sample of households repeatedly at six time points to track the evolution of income elasticities of car ownership over time. Elasticities of car ownership are found to change over time, questioning the existence of a unique equilibrium point between demand and supply that is implicitly assumed in traditional cross-sectional discrete choice car ownership models. Moreover, different household types and households that underwent household type transitions showed differing patterns of change in elasticities. Observed trends in car ownership and income clearly show behavioral asymmetry where the elasticity of procuring an additional car is greater than that of disposing a car. This too shows the inadequacy of traditional cross-sectional models of car ownership which tend to predict symmetry in behavior. The study suggests the importance of incorporating dynamic trends into the forecasting process, which can be accomplished through the use of longitudinal data.