美国铁路车钩缓冲装置的发展(待续)

介绍美国铁路车钩缓冲装置的发展过程、结构特点及运用情况。     

Assessment of economic impacts from unexpected events with an interregional commodity flow and multimodal transportation network model

Loss and damage caused by unscheduled events, especially earthquakes, have sudden and significant impacts not only on the region’s economy where the event occurs but also on other regions. The New Madrid Seismic Zone, located in the center of the United States, could have great impacts on economic activities related to this area, if a major earthquake occurred. Based on the 1993 US Commodity Flow Survey [US Commodity Flow Survey, 1993. Available from: <http://www.bts.gov/ntda/cfs/prod.html>], more than 42% of total commodity flows in the US are related to the greater Midwest, which includes the New Madrid Seismic Zone. If a catastrophic earthquake occurred in this area, the indirect damages could spread far beyond the region, and could have sizable impacts on other regions. A model of interregional commodity flows, incorporating regional input–output relationships, and the corresponding transportation network flows, was applied to assess the economic impacts of such an unexpected event. The economic impacts from the event are described for three hypothetical scenarios, analyzing the magnitude and the extent of the direct and indirect impacts. These analytical results may be used to propose strategic management of the recovery and reconstruction efforts after the event.     

Estuary Management and Recreational Fishing Benefits

Recognition of the benefits to society supported by estuary ecosystem functions and services, and threats to these benefits posed by human activities, has led to various public programs to restore and protect estuaries at the federal, state, and local levels. As available budgets shrink, program administrators and public elected officials struggle to allocate limited restoration and protection funds to the highest priority areas. Economic benefit and cost information can provide useful inputs into this decision-making process by quantifying estuary restoration and protection benefits and costs in commensurate terms. In this paper, a combined actual and intended travel behavior model is described that can be applied to estimate the recreational fishing benefits of estuary restoration and protection. The model was estimated for recreational fishing in the Lower Atchafalaya River Basin estuary along the Gulf of Mexico, Louisiana, USA coast. Changes in freshwater flows into this estuary may affect redfish and speckled trout game fish populations. The model indicates that changes in catch rates of these two species would have a relatively minor affect on annual fishing trips per angler. However, because total effects may be large when effects per angler are aggregated across total anglers, resource management agencies should consider these changes in recreation benefits when evaluating projects that influence the ecology of coastal estuaries, fish populations, and catch rates. Moreover, in other coastal areas or situations, the responsiveness of angling trips to changes in catch rates may vary because of differences in user populations, environmental conditions, fish populations, and fishing experiences.     

Towed-Diver Surveys,a Method for Mesoscale Spatial Assessment of Benthic Reef Habitat: A Case Study at Midway Atoll in the Hawaiian Archipelago

An integrated method for benthic habitat assessment is described, in which divers maneuver boards equipped with digital video, temperature, and depth recorders while being towed behind a small boat. The tow path is concurrently recorded by a GPS receiver, and a layback model is applied to more accurately map the data. Percent cover of salient benthic categories is quantified by whole-image analysis of still frames sampled at 30-s intervals. The results of 15 towed-diver surveys at Midway Atoll in the Hawaiian Archipelago during a mass coral bleaching event are presented to exemplify the method and are compared to results derived from conventional methods. Towed-diver surveys bridge a gap between large-scale mapping efforts using satellite data and small-scale, roving diver assessments, providing a mesoscale spatial assessment of reef habitats. The spatial coverage of towed-diver surveys provides comprehensive data to managers concerning the extent, intensity, differential taxonomic response, and bathymetric correlates of bleaching.     

A Feasibility Study on Indirect Identification of Transmission Forces through Rubber Bushing in Vehicle Suspension System by Using Vibration Signals Measured on Links

This paper presents a feasibility study on using the rubber bushing itself as a sensor for the identification of transmission forces in vehicle suspension systems. The method starts from the idea that the transmission forces can be related to the deformation of the rubber bushing by an appropriate model and the deformation of the rubber bushing can be obtained by estimation of the relative vibration across the bushing. Simple theories are presented to deal with modeling of a given geometry of rubber bushing by a concentric spring and damper, correlating of measurements of the vibration on the links to the stiffness and damping parameters, and selection of the vibration measurement positions. Importance of the measurement position selection in relation to the measurement noise is illustrated by simulation studies. Then, validity of the proposed indirect approach will be shown by applications to a rear suspension system of dual link type.     

Diel vertical migration and feeding in adult female Calanus pacificus, Metridia lucens and Pseudocalanus newmani during a spring bloom in Dabob Bay, a fjord in Washington USA

Diel vertical migration and feeding on phytoplankton by adult female Calanus pacificus, Metridia lucens and Pseudocalanus newmani were simultaneously measured near the end of a phytoplankton bloom. Almost the entire Calanus population migrated out of the deep layer (108–50 m) at night but only about 30% came to the surface (25–0 m). Feeding occurred only at night and was equally high in the surface and intermediate layers, in spite of much higher food concentrations in the surface. Like Calanus, the entire Metridia population was found in the deep layer during the day but unlike Calanus, 20–50% remained in the deep layer at night and most migratory Metridia were collected from the surface layer. Metridia feeding at night was highest in the surface layer but significant feeding also occurred in both the intermediate and deep layers. Migratory behavior of Pseudocalanus was weak, with the proportion of the population in the surface layer increasing from slightly <10% during the day to approx 30% at night. Feeding occurred in both surface and intermediate layers throughout the 24 h but was greater in both layers at night. The different migratory patterns are discussed in the context of our current understanding of the contributions of predator avoidance and feeding to diel vertical migration.     

新型快餐盒生物降解性能试验方法研究

通过固体培养微生物侵蚀试验、液体培养微生物侵蚀试验、降解过程中纤维素酶活性测定、纤维素酶侵蚀试验和降解过程中 Ｃ Ｏ２ 生成体积分数的测定等试验结果分析，认为固体培养微生物侵蚀试验、纤维素酶侵蚀试验及 Ｃ Ｏ２ 生成量测定试验可用于评价新型快餐盒生物降解性能。     

变频技术在锅炉自动燃烧控制系统中的应用

变频技术是近年来应用范围广泛的一门技术，尤其在节约电能、自动控制等方面更为突出。变频技术应用在锅炉的燃烧控制中，既节约了电能，又使燃烧充分而节约了燃煤。由于改变了传统控制模式的运行方式，使锅炉自动燃烧控制系统运行更稳定，安全可靠。该系统应用于青岛四方机车车辆厂、山海关桥梁厂、齐齐哈尔车辆厂、南口机务段等单位，经测试效果明显，推广价值很大。     

Travel mode attitudes,urban context,and demographics: do they interact differently for bicycle commuting and cycling for other purposes?

This study examined whether interactions between travel mode attitudes, urbanization level, and socio-demographics were different for bicycle commuting and cycling for other purposes. Data were obtained from the 2014 wave of the Netherlands mobility panel (MPN). In total, 2673 respondents (18?+?years) who had recorded at least one trip on the days covered by the survey were included in the sample. Four outcomes were constructed, two of which concerned commuting-related cycling: any commuting-related bicycle usage (yes vs. no) and average cycling duration (in hours per weekday). Likewise, two similar outcome variables concerning cycling for other proposes were constructed. These outcomes were analyzed by means of Tobit regression models (cycling duration) and binary logistic models (any bicycle usage). Attitudinal factors concerning different travel modes, namely bus, car, cycling, and train, were constructed by means of factor analysis. The results showed that a positive attitude toward cycling was positively related to bicycle commuting duration, but this association was less strong among those with a positive attitude toward bus use. Having a positive cycling attitude had a weaker association with both bicycle commuting usage and duration in those who do not always have a car available. Regarding cycling for other purposes, cycling attitude had a stronger positive association with cycling duration among residents of very highly urbanized area, compared to residents of less urbanized areas. The available evidence, though limited, suggests that targeting attitudes can have a measurable impact on bicycling, but not to the same extend among all people.