My way or the highway? Framing transportation planners’ attitudes in negotiating professional expertise and public insight

Transportation planning continues to expand beyond traditional engineering and economic performance measures toward a broader scope of impacts across space and society. However, the attitudes of transportation planners as they balance their expert knowledge against public insights are not well-understood. We test a two-dimensional attitudinal framework using survey data from 311 U.S. and Canadian transportation planners. We reveal four attitudinal categories using principal component analysis, and hypothesis testing shows significant differences in personal and institutional attributes across these categories. We discuss what our results mean for training and regulatory measures striving to influence planner attitudes before proposing future directions for research.

     

A fractional perspective to the modelling of Lisbon’s public transportation network

Transportation - Urban growth originates multiscale spatial patterns, such as those of transportation networks. Here, the public transportation network (PTN) of the city of Lisbon is analysed from...     

CATIA modeling method of ship hull with hull line as data input北大核心CSCD

[Objective]To simplify the ship modeling process and improve modeling efficiency, this paper proposes a method for rapidly implementing hull model creation based on hull line drawing.[Methods]Using the CATIA platform, this method adopts the component application architecture (CAA) development tool for secondary development. First, by reading the geometry elements and label information of the hull lines in a drawing, the transformation of the offset points from 2D to 3D is realized. On this basis, the creation of the hull lines, stern and bow is completed, and a 3D wireframe model obtained. Finally, the hull 3D modeling is completed in conjunction with the CATIA native surface creation command. The stability and reliability verification of the developed type value extraction and bow generation program is then carried out via application analysis.[Results]The results show that the compiled program can realize the automatic creation of offset points, transverse lines, waterlines, profile lines and other boundary lines except the top line of the wall, and the centerline and tangent lines created by the bow generator are easily modified and simple for users to operate. [Conclusions]The verification results show that the method of a creating hull model using Generative Shape Design and Drafting with the hull line drawing as the data input is stable, reliable and able to realize rapid hull modeling, giving it certain practical value. © The Author(s) 2022.     

Recent technical and management improvements in US inland waterway transportation

Over the last several years, the US inland waterway transportation industry has significantly reduced its fuel consumption and improved its efficiency, with the side effect of less fuel tax collected per ton of cargo carried, despite the increase in cargo traffic. Fuel tax revenues are used for rehabilitation and construction projects in the inland waterway system, hence the US Army Corps of Engineers, providing us with relevant data over the interval in question, asked us to investigate this surprising reduction, and determine the main technical and fleet management improvements that caused it. Our research involved both visits with most major US inland waterway fleets, interviews with their engineers and managers, as well as statistical analysis of the above data. Technical improvements (such as engine plant efficiency increases), lighter, stronger building materials (such as light steel), and improved designs for better hydrodynamics, were not as important compared to management improvements (such as the use of computer-aided monitoring systems and advanced telecommunications, optimized tow configuration and speed, and increased triangular trips as opposed to simple round trips with returns empty). In addition, the demand for less expensive, imported steel for the US has resulted in an increased percentage of fully loaded return trips from New Orleans to the US Midwest, and hence also in increased fleet utilization.     

Ecology of bottom ice algae: II. Dynamics, distributions and productivity

Spring blooms of bottom ice algae are a common feature of landfast congelation ice in polar regions. Because ice algae are usually associated with a substrate, their population dynamics can be followed with considerable confidence. Although ice algal dynamics are closely related to irradiance, their dynamics and distributions are influenced by other abiotic and biotic factors. Ice algal abundance varies horizontally over all scales examined. Factors such as grazing and nutrient availability may contribute to local and geographic differences. Loss terms for most sea ice assemblages are largely unquantified. Ice algal biomass is most concentrated near the ice-water interface in spring.Environmental factors affecting ice algal abundance and productivity are considered here, emphasizing recent results from several well-studied sites. Biomass accumulation, growth rates and productivity have been documented for spring blooms of bottom interstitial and sub-ice assemblages. On an areal basis biomass accumulation in bottom ice assemblages can be comparable with planktonic systems. At low ambient temperatures and irradiances average specific growth rates (≤ 0.25 d⁻¹) and production rates (≤ 1.0 mg C mg Chl⁻¹ h⁻¹) for ice algae are low. Current methods of measuring productivity are compared. Results are consistently low but variable with little systematic difference among them. At present, apparent differences in productivity between bottom ice assemblages in the Arctic and Antarctic, or among different antarctic assemblages, are so confounded by methodological and other sources of variability that no firm differences can be detected.     

船舶发展与船级社未来的使命

1 引言 随着经济国际化和全球化的发展,航运业已在世界贸易中占据了核心地位.国际贸易中,90%以上的运输任务是由船舶承担的.基本上可以这么说,船舶的优劣,关系着环境状况的好坏.船舶每吨英里所消耗的燃料相当于汽车的1/5,相当于飞机的1/20.正是因为有宽广的海洋,陆上的交通压力才得以减轻.尽管航运业在最近20年间遇到了各种各样的困难,但前景依然是美好的.有显著的迹象表明:亚洲金融危机基本上已得到遏制,国际贸易正朝着健康的方向发展.国际海上贸易平均每增长一个百分点,就会带动世界商船队增加700万载重吨的运力.     

Atmospheric CO2 measurements and error analysis on seasonal air–sea CO2 fluxes in the Bay of Biscay

Atmospheric molar fraction of CO₂ (xCO₂^atm) measurements obtained on board of ships of opportunity are used to parameterize the seasonal cycle of atmospheric xCO₂ (xCO₂^atm) in three regions of the eastern North Atlantic (Galician and French offshore and Bay of Biscay). Three selection criteria are established to eliminate spurious values and identify xCO₂^atm data representative of atmospheric background values. The filtered data set is fitted to seasonal curve, consisting of an annual trend plus a seasonal cycle. Although the fitted curves are consistent with the seasonal evolution of xCO₂^atm data series from land meteorological stations, only ship-board measurements can report the presence of winter xCO₂^atm minimum on Bay of Biscay. Weekly air–sea CO₂ flux differences (mmol C·m^− 2 day^− 1) produced by the several options of xCO₂^atm usually used (ship-board measurements, data from land meteorological stations and annually averaged values) were calculated in Bay of Biscay throughout 2003. Flux error using fitted seasonal curve relative to on board measurements was minimal, whereas land stations and annual means yielded random (− 0.2 ± 0.3 mmol C·m^− 2·day^− 1) and systematic (− 0.1 ± 0.4 mmol C·m^− 2 day^− 1), respectively. The effect of different available sources of sea level pressure, wind speed and transfer velocity were also evaluated. Wind speed and transfer velocity parameters are found as the most critical choice in the estimate of CO₂ fluxes reaching a flux uncertainty of 7 mmol C·m^− 2·day^− 1 during springtime. The atmospheric pressure shows a notable relative effect during summertime although its influence is quantitatively slight on annual scale (0.3 ± 0.2 mmol C·m^− 2·day^− 1). All results confirms the role of the Bay of Biscay as CO₂ sink for the 2003 with an annual mean CO₂ flux around − 5 ± 5 mmol C m^− 2 day^− 1.     

Numerical modelling of fish eggs dispersion at the Patos Lagoon estuary — Brazil

The Patos Lagoon estuary is the most important nursery ground for commercially relevant species of fish and crustaceans in the South of Brazil, maintaining fisheries that sustain 3500 fisher families throughout the Rio Grande do Sul State coastline. Around 80% of the interior estuarine area is very shallow (< 2 m), and recruitment of fish eggs and larvae to the inner parts of the Patos Lagoon estuary is directly related to the circulation pattern in the area, which is controlled by local and non-local wind effects and freshwater discharge. The objective of this study is to investigate the processes controlling the transport of estuarine dependent fish eggs between the Atlantic Ocean and the Patos Lagoon estuary.An integrated numerical system based on a bi-dimensional hydrodynamic model and a Lagrangean transport model of passive particles is applied to a selection of scenarios representing the passage of weather fronts over the area. At this stage, fish eggs are represented as buoyant passive particles. Modelling results are compared against field data for the period under investigation (September/October 1999) and historical records. Short term results are analysed in terms of the meteorological conditions (wind direction, intensity and duration) controlling the transport of eggs to the inner parts of the estuary and the extension of their excursion. This experiment is the first attempt to couple biological and physical information to study fish eggs transport, and to enhance the current knowledge about recruitment of important fisheries resources in southern Brazil.