The vertical disintegration of ship management: choice criteria for third party selection and evaluation

An assessment of the rationale for the vertical disintegration of ship management suggests that there might be compelling economic benefits for the separation of ownership from management. In this context, as a means for developing effective marketing strategies, it is important for ship managers to know the criteria used by current and prospective clients for ship manager selection and evaluation. The aim of this paper is to empirically identify the dimensions for ship manager selection and performance evaluation and their relative importance and to discuss the implications for marketing emanating from such an assessment. The methodology adopted includes the collection of secondary and primary data, both from ship managers and their clients, using interviews and a mail survey. The results indicate the prevailing importance of certain dimensions in selection (e.g. technical ability, reputation, competency) and evaluation (responsiveness, trustworthiness, technical ability), whereas it also found that price alone is not perceived to be as important in ship manager selection. It is concluded that placing emphasis on such dimensions in the formulation of a marketing strategy will contribute towards the attraction and retention of clients, whereas cost-cutting measures to allow price reduction, as well as advertising, will be ineffective over the long term.     

Modelling the silica pump in the Permanently Open Ocean Zone of the Southern Ocean

A coupled 1D physical–biogeochemical model has been built to simulate the cycles of silicon and of nitrogen in the Indian sector of the Permanently Open Ocean Zone of the Southern Ocean. Based on a simplified trophic network, that includes two size classes of phytoplankton and of zooplankton, and a microbial loop, it has been calibrated by reference to surface physical, chemical and biological data sets collected at the KERFIX time-series station (50°40′S–68°25′E). The model correctly reproduces the high nutrient low chlorophyll features typical of the studied area. In a region where the spring–summer mixed layer depth is usually deeper than 60 m, the maximum of chlorophyll never exceeds 1.5 mg m⁻³, and the annual primary production is only 68 g C m⁻² year⁻¹. In the surface layer nitrate is never exhausted (range 27–23.5 mmoles m⁻³) while silicic acid shows strong seasonal variations (range 5–20 mmoles m⁻³). On an annual basis 71% of the primary production sustained by nanophytoplankton is grazed by microzooplankton. Compared to North Atlantic, siliceous microphytoplankton is mainly prevented from blooming because of an unfavourable spring–summer light-mixing regime. Silicic acid limitation (high half saturation constant for Si uptake: 8 mmoles m⁻³) also plays a major role on diatom growth. Mesozooplankton grazing pressure excerpts its influence especially in late spring. The model illustrates the efficiency of the silica pump in the Southern Ocean: up to 63% of the biogenic silica that has been synthetized in the photic layer is exported towards the deep ocean, while only 11% of the particulate organic nitrogen escapes recycling in the surface layer.     

Locating new passenger facilities on a transportation network

This paper examines the problem of locating additional passenger facilities on a transportation network to supplement ones that already exist. A distinction is made between “supporting” facilities which operate only in concert with already existing ones and “new” facilities which are self-sufficient and operate independently. It is shown that, when the objective is to maximize the utility of travel times to all users, at least one set of optimal locations for the new facilities exist on the nodes of the network if the utility function for travel times is convex. This result is proven under very general conditions including the assumption of a probabilistic transportation network, i.e. a network where travel times on network branches are random variables. A straightforward algorithm for solving a specific simple case is also provided and the results are illustrated by examples.     

Hydrology, sediment yield, erosion and sedimentation rates in the estuarine environment of the Ria de Vigo, Galicia, Spain

The aim of this study is to provide a budget study with calculated erosion rates. Three methods have been used to calculate sediment yield and denudation rates in the Ria de Vigo: (1) measurements of sediment loads, (2) measurements of sediment accumulation rates at the coast, (3) theoretical calculations of potential denudation. Sediment loads and water discharge were measured over a period of 14 months from May 1997 to July 1998. Two of the tributaries entering the Ria de Vigo were monitored for 12 more months, from May 2000 to May 2001, to observe changes in discharge and sediment loads. This period corresponded with atypical precipitation, with peak monthly values (600 mm) three times higher than those on record.Water rating curves are typically exponential. Suspended and dissolved loads vary for different rivers, showing values of 1.5 to 130 mg/l during 1997/1998. For 2000/2001, these values are twice as high. Suspended load versus discharge relationships for 1997/1998 were logarithmic, but data from 2000/2001 does not fit the same equation. Dissolved loads are several times higher than suspended loads in almost all cases. Dissolved load concentrations vary more widely with discharge than suspended loads. This is probably due to local pollution and contamination from marine spray in areas closer to the sea.Second, erosion rates and bed load sediment yields were calculated from accumulation rates at the Ramallosa Complex. Well-preserved estuarine and tidal sediments, associated with the Minor River, have accumulated in this area during the Holocene. ¹⁴C ages allow calculation of sedimentation rates (SR) for two intervals. The lower interval extends from 2001 to 484 years BP and yields an SR of 1.12 mm/a. The upper interval extends from 484 years BP to the present and has an SR of 3.3–4.4 mm/a. These differences may be explained by basin dynamics as the beach progressively encloses the area and also by human interference. From sedimentary facies analysis it is concluded that 90% to 95% of the accumulated deposits were transferred to the basin as bed load. Muddy deposits (mostly marshes) are better developed at the upper part of the sediment pile, and inner areas, indicating a progressive shallowing and filling up of the basin. Most of suspended load is exported to the ria, whereas the Ramallosa Complex acts as a sediment sink for bed load derived material.Calculated potential erosion rates using Ahnert's [Am. J. Sci. 268 (1970) 243] equation show lower values than those estimated from river load concentrations. Potential erosion rates for the Minor River are higher than for the Lagares River which contrast with mechanical denudation rate values from river loads during 1997/1998 which are higher for the Lagares River. During 2000/2001 MDR values were higher than those of the potential erosion rates for both rivers, in line with the extremely high precipitation. Higher values in the Lagares could be in part due to human interference.     

Experimental and numerical investigation of fuel mixing effects on soot structures in counterflow diffusion flames

Experimental and numerical analyses of laminar diffusion flames were performed to identify the effect of fuel mixing on soot formation in a counterflow burner. In this experiment, the volume fraction, number density, and particle size of soot were investigated using light extinction/scattering systems. The experimental results showed that the synergistic effect of an ethylene-propane flame is appreciable. Numerical simulations showed that the benzene (C₆H₆) concentration in mixture flames was higher than in ethylene-base flames because of the increase in the concentration of propargyl radicals. Methyl radicals were found to play an important role in the formation of propargyl, and the recombination of propargyl with benzene was found to lead to an increase in the number density for cases exhibiting synergistic effects. These results imply that methyl radicals play an important role in soot formation, particularly with regard to the number density.     

An economic model for sustainable harbor trucking

Truck emissions at a port may have a severe impact on neighbors, resulting in a politically sensitive sustainability issue for the port management. Strict emissions controls may adversely affect throughput whereas the lack of strict controls will be unacceptable to local citizens and environmental interests. We develop an economic model minimizing cost of truck emissions control and collateral production changes and apply it to decision making for a port seeking to meet a throughput goal while also attempting to satisfy an emissions constraint. Outcomes predicted by the model allow informed decisions about the impact of controls.     

斯德哥尔摩的拥挤收费政策——政策实施5年后的效果、接受度及经验启示

根据2006年拥挤收费政策试运行结束后的公民投票结果,2007年,斯德哥尔摩正式实施了该政策。讨论了其至2011年6月首个5年内的政策实施效果。结果表明,受到外部因素影响,由收费引起的交通减少量随时间推移稍有增加。2008年的清洁汽车免税措施可显著提高销售量。结合最新研究成果和瑞典的经验,讨论了公众接受度和政治接受度。得到的结论是：拥挤收费对交通系统的主客观影响,以及环境和政治态度,是公众支持拥挤收费的基础;同时,为了获得政治支持,必须要进行体制改革、解决权力问题。最后,简要讨论了拥挤收费的实施对瑞典交通规划进程的可能影响。     

临床致病性不动杆菌的分子生物学鉴定

目的对临床致病性不动杆菌进行种属鉴定,并比较3种方法(44℃生长试验、特异性引物PCR扩增和16SrRNA测序)对鲍曼不动杆菌鉴定的特异性、准确性及应用价值。方法收集临床致病不动杆菌56株,首先接种在胰蛋白胨大豆肉汤中44℃进行培养,观察是否可以生长;其次,提取56株不动杆菌基因组DNA,用两组不同的特异性引物进行PCR扩增鉴定;最后,用通用引物对56株不动杆菌的16SrRNA进行测序鉴定。结果 56株不动杆菌中有17株可在44℃生长。经特异性引物PCR扩增鉴定,发现8株鲍曼不动杆菌和3株13TU型不动杆菌均可在44℃中较早较快生长。金标准16SrRNA测序确定56株不动杆菌中含有9个种,其中鲍曼不动杆菌和13TU型不动杆菌的鉴定结果与特异性引物PCR扩增法相同。结论应用分子生物学方法鉴定鲍曼不动杆菌具有准确、高效且可重复性高的优点,尤其是特异性PCR扩增法,可作为较难诊断的鲍曼不动杆菌的首选鉴定方法。     

Power control strategy for preventing thermal failure of passively cooled automotive battery packs

Safety mechanism is required for an automotive battery pack to prevent thermal failure which could lead to catastrophic events. Passively cooled battery packs can prevent thermal failure by conducting adaptive control of battery power without any external cooling device. The key to this power control is how to secure battery safety while minimizing energy loss. This paper proposes a novel, adaptive power control strategy for automotive passive-cooling battery packs. Four different cases with electrochemical battery model are simulated and compared to each other according to a city driving profile. Driving simulation result confirmed that the present power control algorithm is an effective solution for preventing thermal failure along with improving energy efficiency of automotive battery packs.