Recent Results on Weakly Compact Operators on Banach Lattices

There have been many really positive results concerning the weakly compact operators on Banach lattices in terms of their order structure as well as in many respects. This paper will survey some known recent results in this area.     

Forecasting ridership for a metropolitan transit authority

The recent volatility in gasoline prices and the economic downturn have made the management of public transportation systems particularly challenging. Accurate forecasts of ridership are necessary for the planning and operation of transit services. In this paper, monthly ridership of the Metropolitan Tulsa Transit Authority is analyzed to identify the relevant factors that influence transit use. Alternative forecasting models are also developed and evaluated based on these factors—using regression analysis (with autoregressive error correction), neural networks, and ARIMA models—to predict transit ridership. It is found that a simple combination of these forecasting methodologies yields greater forecast accuracy than the individual models separately. Finally, a scenario analysis is conducted to assess the impact of transit policies on long-term ridership.     

Using Incentives to Reduce Bycatch and Discarding: Results Under the West Coast Catch Share Program

Abstract

Catch share management was implemented in the bottom trawl sector of the West Coast Groundfish fishery in 2011 to address a range of issues including high bycatch and discard rates. The catch share program was designed to remove the incentives to discard through full catch accounting, tradeable quotas, increased flexibility in fishing, and penalties for catch overages. We assess the effectiveness of the program in meeting its environmental objectives by comparing discard weights, proportions, and variability from 2004–2010 with 2011–2016. We analyzed these metrics for species managed using quota, including historically overfished stocks, as well as for non-quota species caught in the fishery. Discard amounts decreased over time for all species and declined to historic lows after the implementation of the program, remaining low through 2016 with much less inter-annual variability. Mean annual discards of two highly-targeted quota species, sablefish and Dover sole, showed the greatest decreases, falling by 97 and 86%, respectively. The discard proportion of overfished quota species fell by 50% on average. The unanticipated decline in discards of non-quota species as well as the decreased variability in discard amounts for all species indicate that the incentives produced by catch share management provided additional ecosystem benefits.     

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.