ブリルアン散乱と誘電分光によるリラクサー強誘電体の電場効果の研究

筑波大学 (University of Tsukuba)201

New MAX phase superconductor Ti2GeC: A first-principles study

This is the first DFT-based first-principles prediction of the detailed optical and thermodynamic properties, including Vickers hardness and Fermi surface of 211 MAX phase Ti2GeC for which superconductivity (Tc~ 9.5 K) was reported very recently. The calculated structural properties are in excellent agreement with experiments. Our results on elastic parameters indicate a slight elastic anisotropy and brittleness of the compound. The chemical bonding is seen to be a combination of covalent, ionic and metallic nature. The rather stronger covalent bonding is responsible for its high Vickers hardness of 11.6 GPa. The investigated Fermi surface is formed mainly by the low-dispersive bands, which should be responsible for the presence of superconductivity in Ti2GeC. All the optical properties are evaluated and analyzed for two different polarization directions of incident photon. The temperature and pressure dependence of primitive cell volume, thermal expansion coefficient, specific heats, bulk modulus, and Debye temperature of Ti2GeC are derived from the quasi-harmonic Debye model with phononic effect and the various implications are discussed in details

Pilot study on the distribution of caseous lymphadenitis in Korean native goats and the relationship between sex and age in disease occurrence

Caseous lymphadenitis (CLA) caused by Corynebacterium pseudotuberculosis is a chronic disease that affects goats. The Korean native goat (KNG) is the most popular goat breed raised in Korea. In this study, the distribution of CLA in the KNG population and the relevance of sex and age in disease development were determined. From March 2020 to February 2021, 1,177 KNGs from 110 farms were assessed. The distribution of CLA in animals was determined by a veterinary inspector who performed gross examinations of goat carcasses and confirmed diagnoses via polymerase chain reaction and bacteriological examination. The CLA detection rate in the KNG population was 19.80%, and more than half of the farms were affected by the disease (56.36%). A statistically significant difference was observed among the sex groups, with castrated males (13.98%) having the lowest detection rate, followed by intact males (22.48%) and females (24.09%), suggesting that castration has a positive effect on reducing the risk of CLA (p < 0.05). In terms of age groups, an increased detection rate of 28.16% was observed in the late adult (>2 years) group. Phylogenetic analysis indicated that the RNA polymerase beta subunit-encoding gene can effectively differentiate biovar ovis from biovar equi and can be used for further epidemiological studies of C. pseudotuberculosis. This is the first nationwide surveillance study of CLA distribution to confirm the continuous occurrence of CLA in Korean goat farms. Future studies should include risk factor analyses of CLA based on herd levels to prevent and control this disease in Korea

Understanding the road traffic congestion relief impacts of public transport

The primary objective of this research is to understand the congestion relief impacts of public transport. It is suggested in this research that none of the existing measures of traffic congestion provides information on the extent to which traffic congestion is relieved by public transport. In addition, previous studies related to traffic congestion relief have not quantified the relationship between the presence of public transport and the amount of traffic congestion of a city. The research develops a new measurement index which can be used as a relative measure of the city-wide congestion relief impacts of public transport. The proposed research framework consists of three main components: a congestion relief valuation framework that compiles relevant evaluation research and explores mode shift; an experimental modelling approach that analyses changes in congestion measures as a result of alternative public transport scenarios; and a relative measure development method that constructs a congestion relief index for expressing the city wide congestion relief impact of public transport in a generalised form. An examination of secondary evidence demonstrating changes in mode split associated with changes in public transport suggests that about one third of existing public transport users would contribute to additional car trips if public transport were removed. This includes all car drivers and half of the car passengers. A comparative assessment of international research valuing the congestion relief benefits of public transport reveals that congestion relief impacts are valued at between 4.4 and 151.4 Australian cents (2008 value) per marginal vehicle-kilometre of travel with an average of 45.0 cents. Valuations are higher for circumstances with greater degrees of traffic congestion and also where both travel time and vehicle operating cost savings are considered. Experimental transport modelling analysis has been performed to understand the spatial distribution of congestion relief and the effects of different public transport modes. In addition, a new measure called the congestion relief index (CRI) has been developed for use as a comparative index of the congestion relief impact of public transport in cities. The proposed CRI integrates a number of different dimensions of city and transport characteristics into a single measure. The lessons learned from this study include (i) public transport plays a significant role in relieving road traffic congestion in cities; (ii) the wider significance of public transport in relieving congestion outside the central location of the metropolitan area challenges the traditional view that public transport and its impact on congestion is an issue only for central cities; (iii) public transport modes differ in their contribution to congestion relief, but the particular characteristics significantly influencing this impact include patronage, trip length, and spatial coverage; (iv) large-scale public transport systems in large cites provide significant high congestion reduction benefits in comparison to a small-scale systems in small cities; (v) the underlying dimensions of elements affecting the congestion relief impact of public transport in cities can be classified into three broad categories – (1) the public transport-oriented factor, (2) the car-deterrence factor, and (3) the urbanform factor; (vi) the car-deterrence factor has the strongest influence on public transport congestion relief, followed by the public transport-oriented factor and the urban-form factor; (vii) high congestion relief impacts are obtained in cities characterised by high public transport availability and patronage, high urban density and low car ownership and use

Achieving sustainable urban transport mobility in post peak oil era

Peak oil is the term used to describe the point at which global oil production will peak and thereafter start to decline. Recognising that transport uses a significant portion of global energy, the shortage of fossil fuel in post peak oil era will pose a global challenge in the transport sector. The paper presents an assessment of international research to illustrate the possible time frame of peak oil. It investigates the key implications of the oil shortage that threaten to render the urban transport system of Australia ineffective. Synthesis of documented research evidence suggests three major implications in the urban transport sector: (1) a reduction of mobility for individuals, (2) an increase of transport disadvantage, and (3) a disruption of urban freight movement. In addition, the paper explores strategies to cope with the devastating effects of the shortage of the fossil fuel in the post peak oil era. A number of strategies to achieve sustainable mobility in the future urban transport system are presented. These strategies are summarised into three main themes: (1) a mode shift to alternate transport modes, (2) an integration of land use and transport planning, and (3) a global technical effort for alternate fuels and vehicles. It is expected that a concerted global effort in this regard can have a far-reaching effect in achieving sustainability in urban transport mobility

Understanding the road traffic congestion relief impacts of public transport

The primary objective of this research is to understand the congestion relief impacts of public transport. It is suggested in this research that none of the existing measures of traffic congestion provides information on the extent to which traffic congestion is relieved by public transport. In addition, previous studies related to traffic congestion relief have not quantified the relationship between the presence of public transport and the amount of traffic congestion of a city. The research develops a new measurement index which can be used as a relative measure of the city-wide congestion relief impacts of public transport. The proposed research framework consists of three main components: a congestion relief valuation framework that compiles relevant evaluation research and explores mode shift; an experimental modelling approach that analyses changes in congestion measures as a result of alternative public transport scenarios; and a relative measure development method that constructs a congestion relief index for expressing the city wide congestion relief impact of public transport in a generalised form. An examination of secondary evidence demonstrating changes in mode split associated with changes in public transport suggests that about one third of existing public transport users would contribute to additional car trips if public transport were removed. This includes all car drivers and half of the car passengers. A comparative assessment of international research valuing the congestion relief benefits of public transport reveals that congestion relief impacts are valued at between 4.4 and 151.4 Australian cents (2008 value) per marginal vehicle-kilometre of travel with an average of 45.0 cents. Valuations are higher for circumstances with greater degrees of traffic congestion and also where both travel time and vehicle operating cost savings are considered. Experimental transport modelling analysis has been performed to understand the spatial distribution of congestion relief and the effects of different public transport modes. In addition, a new measure called the congestion relief index (CRI) has been developed for use as a comparative index of the congestion relief impact of public transport in cities. The proposed CRI integrates a number of different dimensions of city and transport characteristics into a single measure. The lessons learned from this study include (i) public transport plays a significant role in relieving road traffic congestion in cities; (ii) the wider significance of public transport in relieving congestion outside the central location of the metropolitan area challenges the traditional view that public transport and its impact on congestion is an issue only for central cities; (iii) public transport modes differ in their contribution to congestion relief, but the particular characteristics significantly influencing this impact include patronage, trip length, and spatial coverage; (iv) large-scale public transport systems in large cites provide significant high congestion reduction benefits in comparison to a small-scale systems in small cities; (v) the underlying dimensions of elements affecting the congestion relief impact of public transport in cities can be classified into three broad categories – (1) the public transport-oriented factor, (2) the car-deterrence factor, and (3) the urbanform factor; (vi) the car-deterrence factor has the strongest influence on public transport congestion relief, followed by the public transport-oriented factor and the urban-form factor; (vii) high congestion relief impacts are obtained in cities characterised by high public transport availability and patronage, high urban density and low car ownership and use

Achieving sustainable urban transport mobility in post peak oil era

Peak oil is the term used to describe the point at which global oil production will peak and thereafter start to decline. Recognising that transport uses a significant portion of global energy, the shortage of fossil fuel in post peak oil era will pose a global challenge in the transport sector. The paper presents an assessment of international research to illustrate the possible time frame of peak oil. It investigates the key implications of the oil shortage that threaten to render the urban transport system of Australia ineffective. Synthesis of documented research evidence suggests three major implications in the urban transport sector: (1) a reduction of mobility for individuals, (2) an increase of transport disadvantage, and (3) a disruption of urban freight movement. In addition, the paper explores strategies to cope with the devastating effects of the shortage of the fossil fuel in the post peak oil era. A number of strategies to achieve sustainable mobility in the future urban transport system are presented. These strategies are summarised into three main themes: (1) a mode shift to alternate transport modes, (2) an integration of land use and transport planning, and (3) a global technical effort for alternate fuels and vehicles. It is expected that a concerted global effort in this regard can have a far-reaching effect in achieving sustainability in urban transport mobility.Peak oil Transport energy Oil vulnerability Transport disadvantage Sustainability Mobility

Modeling the Spatial Impacts of Public Transport on Traffic Congestion Relief in Melbourne, Australia

This paper presents experimental modeling that explores the congestion relief effect of transit in Melbourne, Australia. The method adopts a four-step model and assumptions on transit user diversion to auto travel when all or part of the transit system is removed in the a.m. peak. When all transit is removed, diversion to autos causes more than 1,000 additional road links to become congested and increases congestion by 30%. More than 1.3 million additional auto vehicle kilometers of travel occurred and some 97,000 vehicle hours were added under this assumption. Congestion delay increased by more than 150%. Analysis of the separate contributions of transit trips to the central business district (CBD) and greater-CBD areas shows that they contribute to about 40% and 53% of congestion relief in total. When individual transit modes are separately removed, heavy rail use manifests the greatest effects on congestion relief across all suburbs (inner, middle, and outer). Bus effects are second in middle and outer Melbourne, with similar effects to rail use in outer Melbourne. Tram use shows little effect in outer suburbs, but it is significant in inner areas. The greatest percentage change in congestion measures (vehicle hours/delay vehicle hours) is observed in inner Melbourne. However, absolute changes in measures are substantially higher in middle and outer Melbourne, as a result of the bigger spatial scale of these areas. Overall findings increase the understanding of how transit acts to make cities perform more efficiently. An important outcome is the wider non-CBD-based effects on congestion relief, challenging the traditional view that transit and its effect on congestion is an issue only for central cities