Effect of WO<Subscript>3</Subscript> nanoparticle loading on the microstructural,mechanical and corrosion resistance of Zn matrix/TiO<Subscript>2</Subscript>-WO<Subscript>3</Subscript> nanocomposite coatings for marine application

In this study, for marine application purposes, we evaluated the effect of process parameter and particle loading on the microstructure, mechanical reinforcement and corrosion resistance properties of a Zn-TiO₂-WO₃ nanocomposite produced via electrodeposition. We characterized the morphological properties of the composite coatings with a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS). We carried out mechanical examination using a Dura Scan hardness tester and a CERT UMT-2 multi-functional tribological tester. We evaluated the corrosion properties by linear polarization in 3.5% NaCl. The results show that the coatings exhibited good stability and the quantitative particle loading greatly enhanced the structural and morphological properties, hardness behavior and corrosion resistance of the coatings. We observed the precipitation of this alloy on steel is greatly influenced by the composite characteristics.     

Effect of injection angle on artificial cavitation using the design of experiment method

Using the supercavitation phenomenon is necessary to reach high velocities underwater. Supercavitation can be achieved in two ways: natural and artificial. In this article, the simulation of flows around a torpedo was studied naturally and artificially. The validity of simulation using theoretical and practical data in the natural and artificial phases was evaluated. Results showed that the simulations were consistent with the laboratory results. The results in different injection coefficient rates, injection angles, and cavitation numbers were studied. The obtained results showed the importance of cavitation number, injection rate coefficient, and injection angle in cavity shape. At the final level, determining the performance conditions using the Design of Experiment (DOE) method was emphasized, and the performance of cavitation number, injection rate coefficient, and injection angle in drag and lift coefficient was studied. The increase in injection angle in the low injection rate coefficient resulted in a diminished drag coefficient and that in the high injection rate coefficient resulted in an enhanced drag coefficient.     

A conceptual model of the strongly tidal Columbia River plume

The Columbia River plume is typical of large-scale, high discharge, mid-latitude plumes. In the absence of strong upwelling winds, freshwater from the river executes a rightward turn and forms an anticyclonic bulge before moving north along the Washington coast. In addition to the above dynamics, however, the river plume outflow is subject to large tides, which modify the structure of the plume in the region near the river mouth. Observations based on data acquired during a summer 2005 cruise indicate that the plume consists of four distinct water masses; source water at the lift-off point, and the tidal, re-circulating and far-field plumes. In contrast to most plume models that describe the discharge of low-salinity estuary water into ambient high-salinity coastal water, we describe the Columbia plume as the superposition of these four plume types.We focus primarily on a conceptual summary of the dynamics and mutual interaction of the tidal and re-circulating plumes. The new tidal plume flows over top of the re-circulating plume and is typically bounded by strong fronts. Soon after the end of ebb tide, it covers roughly 50–100% of the re-circulating plume surface area. The fronts may penetrate well below the re-circulating plume water and eventually spawn internal waves that mix the re-circulating plume further. The re-circulating plume persists throughout the tidal cycle and corresponds to a freshwater volume equivalent to 3–4 days of river discharge. Finally, the plume water masses are distinguished from one another in term of surface chlorophyll concentration, suggesting that the above classification may also describe different biological growth regimes. The low-salinity re-circulating plume serves as an extension of the estuary into the coastal ocean, or an “estuary at sea”, because residence times during periods of high river flow are greater than those in the estuary.     

Experiments on the survival of six brackish macro-invertebrates from the Baltic Sea after dredged spoil coverage and its implications for the field

Physical disturbance by disposal of dredged materials in estuarine and coastal waters may result in burial of benthic fauna. Survival rates depend on a variety of factors including the type and amount of disposed materials and the lifestyle of the organisms. Laboratory burial experiments using six common macrobenthic invertebrates from a brackish habitat of the western Baltic Sea were performed to test the organisms' escape reaction to dredged material disposal. Experimental lab-results were then extrapolated to a field situation with corresponding bottom topography and covering layer thicknesses at experimental field disposal study sites. Resulted survival rates were then verified by comparison with results of an earlier field study at the same disposal sites.Our experimental design in the lab included the disposal of two types of dredged material (i.e. ‘till’ and ‘sand/till mixture’) and two covering layer depths (i.e. 10–20 cm and 14–40 cm). All three bivalves Arctica islandica (Linnaeus), Macoma balthica (Linnaeus), Mya arenaria (Linnaeus) and the polychaete Nephtys hombergii (Savigny) successfully burrowed to the surface of a 32–41 cm deposited sediment layer of till or sand/till mixture and restored contact with the overlying water. These high escape potentials could partly be explained by the heterogeneous texture of the till and sand/till mixture with ‘voids’. The polychaete Bylgides (Harmothoe) sarsi (Malmgren) successfully burrowed through a 16 cm covering layer whereas the polychaete Lagis koreni (Malmgren) showed almost no escaping reaction. No general differences in escape behaviour after burial were detected between our test species from the brackish habitat and those reported in the literature for the same species in marine environments. However, a size-dependence in mobility of motile polychaetes and M. arenaria was apparent within our study. In comparison to a thick coverage, thin covering layers (i.e. 15–16 cm and 20 cm) increased the chance of the organisms (N. hombergii and M. arenaria) to reach the sediment surface after burial. This was not observed for the other test species. While crawling upward to the new sediment surfaces burrowing velocities of up to 8 cm d^− 1 were observed for the bivalves and up to 20 cm d^− 1 for N. hombergii. Between 17 and 79% of the test organisms showed burrowing activity after experimental burial. The survival rate (defined as the ability to regained contact with the sediment surface) ranged from 0 to 33%, depending on species and on burial depth. The organisms reached the sediment surface by burrowing (polychaetes and bivalves) and/or by extending their siphons to the new sediment surface (bivalves). The extrapolation of laboratory survival rates to the two disposal sites was obtained based on the in situ thicknesses of the dredged spoil layers measured by multi-beam echo sounder. This resulted in total average survival rate estimates for the test species of 45 and 43% for the two disposal sites. The results obtained during the laboratory tests and the following extrapolation to the field were verified by the range of results from a previous field study, using grab sampling shortly before and after a disposal event in June 2001. The effect of dredged material disposal on the tested Baltic Sea benthic macrofauna was assessed by extrapolating the verified laboratory results to the field.     

电动车组车体弯曲振动标准频率的保证

采用有限元法对电动车组车体的固有振动频率进行了计算.根据计算结果提出了改进电动车组车体结构的建议.     

CO2 emission statistics for the world commercial fleet

The purpose of this paper is to present an analysis of carbon dioxide (CO₂) emissions of the world commercial fleet. The analysis is based on the Lloyds-Fairplay world ship database for 2007 and produces various emissions statistics of the following major ship types: bulk carriers, crude oil tankers, container vessels, product/chemical carriers, LNG carriers, LPG carriers, reefer vessels, Ro-Ro vessels and general cargo ships. A separate analysis is carried out for small vessels under 400 GRT and for passenger vessels. The main outputs from this analysis for each ship type-size bracket are the emitted grams of CO₂ per tonne-km and an estimate of the total CO₂ produced in a year. The methodology for estimating these statistics is described, and a comparison with other studies is made.     

An energy-cost approach for evaluation of operating systems in container terminals

The planning, design and development of a container terminal with optimum size and capacity and with a minimum capital cost is fundamentally dependent upon the loading and discharging operations at the quayside. Achieving this purpose, terminal operators have to choose the best operating system in the container yard. The decision on which equipment is used at container terminals depends on several factors. The purpose of this study is to provide a new decision making tool using the first law of thermodynamics. It considers a port as a control volume of a fluid system and models the port and its traffic on it. The results of this study evaluate container yard operating systems and set up a basis for decision making to select the best alternatives.     

Design of ANFIS networks using hybrid genetic and SVD methods for modeling and prediction of rubber engine mount stiffness

Genetic Algorithm (GA) and Singular Value Decomposition (SVD) are deployed for optimal design of both the Gaussian membership functions of antecedents and the vector of linear coefficients of consequents, respectively, of ANFIS networks. These networks are used for stiffness modelling and prediction of rubber engine mounts. The aim of such modelling is to show how the stiffness of an engine mount changes with variations in geometric parameters. It is demonstrated that SVD can be optimally used to find the vector of linear coefficients of conclusion parts using ANFIS (Adaptive Neuro-Fuzzy Inference Systems) models. In addition, the Gaussian membership functions in premise parts can be determined using a GA. In this study, the stiffness training data of 36 different bush type engine mounts were obtained using the finite element analysis (FEA).     

Trip chaining as a barrier to the propensity to use public transport

Trip chaining is a growing phenomenon in travel and activity behaviour. Individuals increasingly seek out opportunities to minimise the amount of travel required as part of activity fulfilment, given the competing demands on time budgets and their valuation of travel time savings. This search for ways of fulfilling (more) activities with less travel input has produced a number of responses, one of which is trip chaining. A particularly important policy implication of trip chaining is the potential barrier it creates in attracting car users to switch to public transport. This paper seeks to improve our understanding of trip chaining as a barrier to public transport use. A series of discrete choice models are estimated to identify the role that socio-economic and demographic characteristics of households have on the propensity to undertake trip chains of varying degrees of simplicity/complexity that involve use of the car or public transport with an embedded commuting or non-commuting primary purpose. Multinomial logit, nested logit and random parameter logit models are developed and contrasted to establish the gains in relaxing the strict conditions of the multinomial logit model.     

Performance measures and data requirements for congestion management systems

Many metropolitan areas have started programs to monitor the performance of their transportation network and to develop systems to measure and manage congestion. This paper presents a review of issues, procedures, and examples of application of geographic information system (GIS) technology to the development of congestion management systems (CMSs). The paper examines transportation network performance measures and discusses the benefit of using travel time as a robust, easy to understand performance measure. The paper addresses data needs and examines the use of global positioning system (GPS) technology for the collection of travel time and speed data. The paper also describes GIS platforms and sample user interfaces to process the data collected in the field, data attribute requirements and database schemas, and examples of application of GIS technology for the production of maps and tabular reports.