Networks, commuting and spatial structures: An introduction

JTLU vol. 2, no. 3, (2010) pp 1-4This article introduces vol. 2, no. 3 issue of Journal of Transport and Land Use

Second-degree Price Discrimination and Inter-group Effects in Airline Routes between European Cities

This paper presents a model of second-degree price discrimination and inter-group effects to describe the full-service pricing behaviour in the passenger aviation market. Consumer heterogeneity is assumed on both a horizontal and a vertical dimension, while various distinct market structures, some of which include low-cost carriers (LCCs), are considered. In the theoretical model framework, we derive that the rivalry between full-service carriers (FSCs) reduces fare differences between the business and leisure segments. Furthermore, the presence of LCCs increases fare gaps between leisure and business travellers, and it also induces FSCs to decrease fares in the leisure segment and eventually to increase them in the business one. This last outcome emerges from a change in passenger arrangements caused by inter-group effects. In our empirical analysis, we use data on published airfares of Lufthansa, British Airways, KLM and Alitalia for the main city-pairs from Italy to Germany, the UK and the Netherlands. Our results show that the empirical results provide support for our theoretical propositions

Consumer Valuation of Driving Range: A Meta-Analysis

We perform a meta-analysis of studies investigating consumers' preferences for electric and other alternative fuel vehicles to provide insights into the way consumers trade off driving range for capital costs. We find that consumers are willing to pay, on average, between 47 and 64 USD for a one-mile increase in vehicle's range. The short driving range of most currently available electric vehicles entails that they should be offered at prices around half the price of their conventional counterparts in order to be considered competitive alternatives, ceteris paribus. In line with intuition, but in contrast to most specifications employed in primary studies, we find evidence that consumers' marginal willingness to pay (WTP) is decreasing in driving range. The wide divergence in the estimates of welfare measures among the examined studies can be mainly attributed to differences in the study design, the location at which the study was conducted and the size of the study's sample. Provided that a large scale introduction of electric vehicles is a policy aim, our findings support the continuation of R&D efforts directed towards the reduction of battery costs and the development of advanced battery technologies permitting higher driving ranges than the ones currently achievable by most commercially available electric cars

Immobilized photocatalyst on stainless steel woven meshes assuring efficient light distribution in a solar reactor

An immobilized TiO₂ photocatalyst with a high specific surface area was prepared on stainless steel woven meshes in order to be used packed in layers for water purification. Immobilization of such a complex shape needs a special coating technique. For this purpose, dip coating and electrophoretic deposition (EPD) techniques were used. The EPD technique gave the TiO₂ coating films a better homogeneity and adhesion, fewer cracks, and a higher ^·OH formation than the dip coating technique. The woven mesh structure packed in layers guaranteed an efficient light-penetration in water treatment reactor. A simple equation model was used to describe the distribution of light through the mesh layers in the presence of absorbing medium (e.g., colored water with humic acids). Maximum three or four coated meshes were enough to harvest the solar UV light from 300 nm to 400 nm with a high penetration efficiency. The separation distance between the mesh layers played an important role in the efficiency of solar light penetration through the coated mesh layers, especially in case of colored water contaminated with high concentrations of humic acid

Import of cytochrome c into mitochondria

The import of cytochrome c into mitochondria can be resolved into a number of discrete steps. Here we report on the covalent attachment of heme to apocytochrome c by the enzyme cytochrome c heme lyase in mitochondria from Neurospora crassa. A new method was developed to measure directly the linkage of heme to apocytochrome c. This method is independent of conformational changes in the protein accompanying heme attachment. Tryptic peptides of [35S]cysteine-labelled apocytochrome c, and of enzymatically formed holocytochrome c, were resolved by reverse-phase HPLC. The cysteine-containing peptide to which heme was attached eluted later than the corresponding peptide from apocytochrome c and could be quantified by counting 35S radioactivity as a measure of holocytochrome c formation. Using this procedure, the covalent attachment of heme to apocytochrome c, which is dependent on the enzyme cytochrome c heme lyase, could be measured. Activity required heme (as hemin) and could be reversibly inhibited by the analogue deuterohemin. Holocytochrome c formation was stimulated 5–10-fold by NADH > NADPH > glutathione and was independent of a potential across the inner mitochondrial membrane. NADH was not required for the binding of apocytochrome c to mitochondria and was not involved in the reduction of the cysteine thiols prior to heme attachment. Holocytochrome c formation was also dependent on a cytosolic factor that was necessary for the heme attaching step of cytochrome c import. The factor was a heat-stable, protease-insensitive, low-molecular-mass component of unknown function. Cytochrome c heme lyase appeared to be a soluble protein located in the mitochondrial intermembrane space and was distinct from the previously identified apocytochrome c binding protein having a similar location. A model is presented in which the covalent attachment of heme by cytochrome c heme lyase also plays an essential role in the import pathway of cytochrome c

Structure and Thermodynamics of the Mixed Alkali Alanates

The thermodynamics and structural properties of the hexahydride alanates (M2M'AlH6) with the elpasolite structure have been investigated. A series of mixed alkali alanates (Na2LiAlH6, K2LiAlH6 and K2NaAlH6) were synthesized and found to reversibly absorb and desorb hydrogen without the need for a catalyst. Pressure-composition isotherms were measured to investigate the thermodynamics of the absorption and desorption reactions with hydrogen. Isotherms for catalyzed (4 mol% TiCl3) and uncatalyzed Na2LiAlH6 exhibited an increase in kinetics, but no change in the bulk thermodynamics with the addition of a dopant. A structural analysis using synchrotron x-ray diffraction showed that these compounds favor the Fm-3m space group with the smaller ion (M') occupying an octahedral site. These results demonstrate that appropriate cation substitutions can be used to stabilize or destabilize the material and may provide an avenue to improving the unfavorable thermodynamics of a number of materials with promising gravimetric hydrogen densities.Comment: 6 pages, 7 figures,3 tables, submitted to PR

Adaptation to Climate Change in the Transport Sector

In this study, we review the literature on climate change adaptation measures in the transport sector. Many of the measures proposed are rather conceptual and far from concrete, probably due to the fact that climate change effects on transport are either unknown or highly uncertain. Given the limited information on the potential magnitude of climate damages and the various uncertainties involved, postponement of adaptation investments may well be the most sensible strategy at the moment, especially when investments are substantial and irreversible. Furthermore, monitoring of relevant climatic changes and ongoing research into climate change effects are important elements of a pro-active adaptation strategy. Irreversible decisions, such as the ones on spatial organization, likely require a more active strategy, e.g. in the form of making spatial reservations. We further discuss the interdependency between optimal mitigation and adaptation, an issue that is often overlooked in the literature. Finally, most operators and governmental bodies are not used to dealing with risk and uncertainty, and generally base their decisions on single risk values only, likely leading to under- or overinvestment. We discuss several relevant topics in this area and highlight methods that can be used to better deal with these issues. © 2012 Copyright Taylor and Francis Group, LLC

Особенности образования неметаллических включений при производстве углеродистой электростали

Изложены результаты, полученных при реализации нового подхода к решению проблемы образования неметаллических включений (НВ), основанного на анализе генезиса и трансформации НВ в стали по всем этапам сталеплавильно–разливочного и прокатного (применительно к условиям сортопрокатно–проволочного стана) переделов