A PRT airport - Serving a transportation function

Costly and complicated airports have just three basic functions: (1) service, dispatch and recover airplanes; (2) service, process and embark/debark passengers and material; (3) generate operating cost recovery for owner, operator, sponsor. The first function is ground servicing. The second is embarking and loading, with and subsequent recovery of airplanes, unloading and disembarkation. None of the first function require a terminal of any kind. The second function does, and the third function does nothing for air travel. Use major shopping centers for PRT movement, direct to the jetway. No terminal. Place eleven square buildings between the parallel runways, diamond oriented point-to-point, with four parking spaces -the module sides. Airplanes taxi in and away on one center line, 100 feet from the module centered between in-the-ground service connections. PRT connects two story modules, 200 feet on a side. Jetways at each corner also move vertically up and down to load and unload twice as fast, DOWN the jetway, with baggage on conveyors. PRT from neighborhood centers allows passengers to get tickets from local travel agents, and security check from local police. Travel is secure. Parking and the sales tax take is distributed.     

Impact of freshwater on a subarctic coastal ecosystem under seasonal sea ice (southeastern Hudson Bay, Canada). III. Feeding success of marine fish larvae

We monitored the feeding success (percent feeding incidence at length and mean feeding ratio at length) of Arctic cod (Boreogadus saida) and sand lance (Ammodytes sp.) larvae in relation to prey density, light, temperature and potential predator density under the ice cover of southeastern Hudson Bay in the spring of 1988, 1989 and 1990. Both prey density and light limited larval fish feeding. The relationship between feeding success and actual food availability (nauplii density X irradiance) was adequately described by an Ivlev function which explained 64 and 76% of the variance in Arctic cod and sand lance feeding success respectively. By affecting both prey density and irradiance, the thickness of the Great Whale River plume (as defined by the depth of the 25 isohaline) was the main determinant of prey availability. Arctic cod and sand lance larvae stopped feeding when the depth of the 25 isohaline exceeded 9 m. Limitation of feeding success attributable to freshwater inputs occurred exclusively in 1988, the only time when the depth of the 25 isohaline exceeded the 9 m threshold. The close dependence of larval fish feeding success on the timing of the freshet and plume dynamics suggests a direct link between climate and survival of Arctic cod and sand lance larvae. The actual impact of climate fluctuations and/or hydro-electric developments on recruitment will depend on the fraction of the larval dispersal area of the two species that is affected by river plumes.     

Marginal cost pricing of truckload services: A comparison of two approaches

A useful input to the pricing of truckload trucking services is the marginal benefit to the entire system of an additional load going from one region to the next. Two approaches are reviewed for estimating the marginal system benefit. The first is based on a well-known deterministic network formulation in which certain easily obtainable shadow prices provide an estimate of the marginal benefit. The second is based on a nonlinear stochastic formulation which incorporates uncertainty in demand forecasts. Each procedure is reviewed in detail and evaluated in terms of the accuracy with which the actual change in total system profit (found by increasing the demand on a link and completely reoptimizing) matches the estimated benefit.     

An Investigation into Stick-Slip Vibrations on Vehicle/Track Systems

A model for the numerical simulation of vehicle/track interaction and stick-slip vibration is presented. A finite element model is developed to calculate vertical contact forces. These forces are then coupled through the contact patch into a non-linear time-domain model by which the stick-slip vibration behaviour of a wheel-rail system is analysed. The investigation suggests that stick-slip vibration may occur if a vehicle which has a maligned or an initial 'wind-up' wheeiset meets a vertical irregularity or contaminants on the track.     

一种用于地铁轻轨的智能行车控制方法

本文利用模糊建模技术，通过建立调度员决策模型和引入新的思维，设计了高效的市郊铁路行车控制器。此项研究的主要目标是消除基本时刻表偏差及由车站或列车停发进路问题所引起的对列车运行的干扰。本文所提出的方法接近调度员的思维方式，在相关市郊铁路和地铁系统中具有应用价值。     

转向架弹簧减振装置的动态特性

论述了弹簧减振装置基本参数对改善机车车辆运行特性的转向架动态特性的影响.转向架动态特性主要影响机车车辆的总特性.车辆总特性又影响到车辆运行噪声的水平,同时对铁路线路产生不利的影响.     

Seasonal variability in sea surface oceanographic conditions in the Aegean Sea (Eastern Mediterranean): an overview

Seasonal variability and the spatial distribution of sea surface temperatures (SST) and salinities (SSS) are reviewed, in relation to the prevailing climatological conditions, heat fluxes, water budget and general water circulation patterns. Within this context, consideration is given to: sea surface temperatures; air temperatures; precipitation; evaporation; wind speeds and directions; freshwater (mainly riverine) discharges throughout the Aegean; and the exchange of water masses with the Black Sea and eastern Mediterranean Sea. The investigation of satellite images, covering a 6-yr period (1988–1994), has enabled a synthesis of the monthly sea surface thermal distribution to be established.The climate of the Aegean Sea is characterised by annual air temperatures of 16–19.5°C, precipitation of about 500 mm yr⁻¹ and evaporation of some 4 mm d⁻¹. The Aegean has a negative heat budget (approximately −25 W m⁻²) and positive water balance (+ 1.0 m yr⁻¹), when inflow from the Black Sea is considered. During the summer, the (northerly) Etesians are the dominant winds over the Sea.Mean monthly sea surface temperatures (SST) vary from 8°C in the north during winter, up to 26°C in the south during summer. SST depends mainly upon air temperature; there is a month's delay between the former and latter maxima. The sea surface salinity (SSS) varies also spatially and seasonally, ranging from less than 31 psu, in the north, to more than 39 psu, in the southeast; lower values (< 25 psu) occur adjacent to the river mouths. SSSs present their maximum differences during summer, whilst during winter and autumn the distribution of SSS is more uniform. The overall spatial SST and SSS distribution pattern is controlled by: distribution of the (colder) Black Sea Waters; advection of the (warmer) Levantine Waters, from the southeastern part of the Aegean; upwelling and downwelling; and, to a lesser extent, but locally important, freshwater riverine inflows.     

The influence of workplace environment on lung function of shopkeepers working near National Highway in Jalgaon: A note

The inferior ambient air quality was observed near highway passing through Jalgaon urban center. Among the pollutants critical level of particulates are observed at the roadside during May 2003 to April 2004. The shopkeepers working at the highway sides are at high risk of exposure to the air pollution caused by heavy highway traffic. The lung function test of the shopkeepers shows significant decrease in forced vital capacity, forced expiratory volume in one second and peak expiratory flow rate. The regular periodic health checkup and use of nose mask will protect the health of shopkeepers working near National Highway passing through Jalgaon urban center.