5,372 research outputs found

    An Exploratory Study of the Participation in the Sharing Economy: What are the Influencing Variables?

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    The following is an exploratory study undertaken to identify and validate the variables that affect an individual’s decision to participate in the sharing economy. Six variables are tested; five as independent variables and one as a moderator variable. The five are self-technological aptness, self-norm, attitude toward the sharing economy, desire to access a bigger market, and attitude toward environmental friendliness, while the moderator variable is economic benefit. Regarding data: 1000 promiscuously recruited individuals were asked and 479 individuals completed the survey out of which 466 individuals’ responses are used for the data analysis. The self-determination theory provides the basis for the theoretical framework and hypothesis development. The result revealed that all variables showed a statistically significant relationship, except for the self-technologically aptness variable. Moreover, the moderating economic benefit variable exhibited a significant moderation effect on all the variables except in the case of self-technological aptness. Ultimately, this study provides a deeper understanding of those variables and their effect on the participants. Additionally, it presents opportunities for further research in this area. A full and complete report is expected later

    Dynamical mean-field theory of Hubbard-Holstein model at half-filling: Zero temperature metal-insulator and insulator-insulator transitions

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    We study the Hubbard-Holstein model, which includes both the electron-electron and electron-phonon interactions characterized by UU and gg, respectively, employing the dynamical mean-field theory combined with Wilson's numerical renormalization group technique. A zero temperature phase diagram of metal-insulator and insulator-insulator transitions at half-filling is mapped out which exhibits the interplay between UU and gg. As UU (gg) is increased, a metal to Mott-Hubbard insulator (bipolaron insulator) transition occurs, and the two insulating states are distinct and can not be adiabatically connected. The nature of and transitions between the three states are discussed.Comment: 5 pages, 4 figures. Submitted to Physical Review Letter

    Stability of hydrogenation states of graphene and conditions for hydrogen spillover

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    The hydrogen spillover mechanism has been discussed in the field of hydrogen storage and is believed to have particular advantage over the storage as metal or chemical hydrides. We investigate conditions for practicality realizing the hydrogen spillover mechanism onto carbon surfaces, using first-principles methods. Our results show that contrary to common belief, types of hydrogenation configurations of graphene (the aggregated all-paired configurations) can satisfy the thermodynamic requirement for room-temperature hydrogen storage. However, the peculiarity of the paired adsorption modes gives rise to a large kinetic barrier against hydrogen migration and desorption. It means that an extremely high pressure is required to induce the migration-derived hydrogenation. However, if mobile catalytic particles are present inside the graphitic interstitials, hydrogen migration channels can open and the spillover phenomena can be realized. We suggest a molecular model for such a mobile catalyst which can exchange hydrogen atoms with the wall of graphene.open151

    Echocardiographic Features in Canine Myxomatous Mitral Valve Disease: An Animal Model for Human Mitral Valve Prolapse

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    Myxomatous mitral valve disease (MMVD) is the most common heart disease in dogs and has many similarities to human mitral valve prolapse (MVP). Transthoracic echocardiography is a non-invasive method for making a diagnosis and predicting the progression of heart failure (HF) in dogs and humans with mitral regurgitation (MR). It enables clinicians to detect the mitral valve (MV) lesions, to evaluate MR severity, and to assess its impact on cardiac remodeling, myocardial function, left ventricular (LV) filling pressures, as well as pulmonary arterial pressure. Furthermore, advanced ultrasound technologies such as tissue Doppler imaging (TDI), strain and strain rate imaging, and two-dimensional (2D) speckle tracking echocardiography (STE) provide a better assessment of global and regional myocardial function. Although the severity of MR and HF in dogs with MMVD is being evaluated as similar to human cardiology, the veterinary cardiologists are more focused on the severity of cardiac remodeling and cardiac dysfunction caused by MR, because surgical restoration of defected mitral apparatus is rarely done in dogs. The chapter will review conventional echocardiographic features of MMVD in dogs to provide a better understanding of the similarities and discrepancies between canine MMVD and human MVP to veterinary and human cardiologists and researchers

    Electrostatic Power Generation from Negatively Charged, Simulated Lunar Regolith

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    Research was conducted to develop an electrostatic power generator for future lunar missions that facilitate the utilization of lunar resources. The lunar surface is known to be negatively charged from the constant bombardment of electrons and protons from the solar wind. The resulting negative electrostatic charge on the dust particles, in the lunar vacuum, causes them to repel each other minimizing the potential. The result is a layer of suspended dust about one meter above the lunar surface. This phenomenon was observed by both Clementine and Surveyor spacecrafts. During the Apollo 17 lunar landing, the charged dust was a major hindrance, as it was attracted to the astronauts' spacesuits, equipment, and the lunar buggies. The dust accumulated on the spacesuits caused reduced visibility for the astronauts, and was unavoidably transported inside the spacecraft where it caused breathing irritation [1]. In the lunar vacuum, the maximum charge on the particles can be extremely high. An article in the journal "Nature", titled "Moon too static for astronauts?" (Feb 2, 2007) estimates that the lunar surface is charged with up to several thousand volts [2]. The electrostatic power generator was devised to alleviate the hazardous effects of negatively charged lunar soil by neutralizing the charged particles through capacitive coupling and thereby simultaneously harnessing power through electric charging [3]. The amount of power generated or collected is dependent on the areal coverage of the device and hovering speed over the lunar soil surface. A thin-film array of capacitors can be continuously charged and sequentially discharged using a time-differentiated trigger discharge process to produce a pulse train of discharge for DC mode output. By controlling the pulse interval, the DC mode power can be modulated for powering devices and equipment. In conjunction with a power storage system, the electrostatic power generator can be a power source for a lunar rover or other systems. The negatively charged lunar soil would also be neutralized mitigating some of the adverse effects resulting from lunar dust

    RADIATION-INDUCED DISLOCATION AND GROWTH BEHAVIOR OF ZIRCONIUM AND ZIRCONIUM ALLOYS - A REVIEW

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    Zirconium and zirconium alloys are widely used as nuclear reactor core materials such as fuel cladding and guide tubes because they have excellent corrosion and radiation-resistant properties. In the reactor core, zirconium alloys are subjected to high-energy neutron fluence, causing radiation-induced dislocation and growth. To discern a possible correlation between radiation-induced dislocation and growth, characteristics of dislocation and growth in zirconium and its alloys are examined. The radiation-induced dislocation including <a> and <c> dislocation loops is reviewed in various temperature and fluence ranges, and their growth behavior is examined in the same way. To further a fundamental understanding, radiation-induced growth prediction models are briefly reviewed. This research will assist in the design of zirconium based components as well as the safety analysis of various reactor conditions, in both research and commercial reactors.close0
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