Green-Technology Automobiles: Can modern innovations save the environment and consumers\u27 pockets

Cars of the past are notorious for poor fuel efficiency and high carbon emissions. With the presence of hybrid technology, along with a variety of other green innovations, many of these negative side effects can be mitigated. The purpose of this study is to answer the question: how do green technology vehicles compare with similar models that exclude such innovations in relation to efficiency and price? A total of 47 green-tech vehicles were identified and compared against their base model counterparts. Vehicle weight, horsepower, fuel efficiency and other variables were matched within pairs (green-tech vs. base) and between car types (sedans, SUVs and trucks). Regardless of vehicle type and green-tech, weight proved to be an influential factor, showing that as curb weight increased, fuel efficiency decreased. Compared to the base models, green-tech luxury vehicles also exhibited few improvements in fuel efficiency with disproportionately high growth in price. Non-luxury green-tech sedans ranging from 2500lbs to 4000lbs showed the largest improvements in efficiency while also maintaining an average MSRP of $28996±1089, producing a green-tech vehicle that is economically affordable. The impressive results from this category of vehicles suggest that consumer investment in non-luxury green sedans may not only help to save money in fuel consumption, but also save the environment

A two-dimensional mixing length theory of convective transport

The helioseismic observations of the internal rotation profile of the Sun raise questions about the two-dimensional (2D) nature of the transport of angular momentum in stars. Here we derive a convective prescription for axisymmetric (2D) stellar evolution models. We describe the small scale motions by a spectrum of unstable linear modes in a Boussinesq fluid. Our saturation prescription makes use of the angular dependence of the linear dispersion relation to estimate the anisotropy of convective velocities. We are then able to provide closed form expressions for the thermal and angular momentum fluxes with only one free parameter, the mixing length. We illustrate our prescription for slow rotation, to first order in the rotation rate. In this limit, the thermodynamical variables are spherically symetric, while the angular momentum depends both on radius and latitude. We obtain a closed set of equations for stellar evolution, with a self-consistent description for the transport of angular momentum in convective regions. We derive the linear coefficients which link the angular momentum flux to the rotation rate ($\Lambda$- effect) and its gradient ($\alpha$-effect). We compare our results to former relevant numerical work.Comment: MNRAS accepted, 10 pages, 1 figure, version prior to language editio

A study of weather-dependent data links for deep space applications

Weather-dependent data links for deep space applications, and five potential system

The GOSSIP on the MCV V347 Pav

Modelling of the polarized cyclotron emission from magnetic cataclysmic variables (MCVs) has been a powerful technique for determining the structure of the accretion zones on the white dwarf. Until now, this has been achieved by constructing emission regions (for example arcs and spots) put in by hand, in order to recover the polarized emission. These models were all inferred indirectly from arguments based on polarization and X-ray light curves. Potter, Hakala & Cropper (1998) presented a technique (Stokes imaging) which objectively and analytically models the polarized emission to recover the structure of the cyclotron emission region(s) in MCVs. We demonstrate this technique with the aid of a test case, then we apply the technique to polarimetric observations of the AM Her system V347 Pav. As the system parameters of V347 Pav (for example its inclination) have not been well determined, we describe an extension to the Stokes imaging technique which also searches the system parameter space (GOSSIP)

Depletion of carriers and negative differential conductivity in an intrinsic graphene under a dc electric field

The heating of carriers in an intrinsic graphene under an abrupt switching off a dc electric field is examined taking into account both the energy relaxation via acoustic and optic phonons and the interband generation-recombination processes. The later are caused by the interband transitions due to optical phonon modes and thermal radiation. Description of the temporal and steady-state responses, including the nonequilibrium concentration and energy as well as the current-voltage characteristics, is performed. At room temperature, a nearly-linear current-voltage characteristic and a slowly-varied concentration take place for fields up to -- 20 kV/cm. Since a predominant recombination of high-energy carriers due to optical phonon emission at low temperatures, a depletion of concentration takes place below -- 250 K. For lower temperatures the current tends to be saturated and a negative differential conductivity appears below -- 170 K in the region of fields -- 10 V/cm.Comment: 8 pages, 10 figures, extended versio

Thermal-radiation-induced nonequilibrium carriers in an intrinsic graphene

We examine an intrinsic graphene connected to the phonon thermostat at temperature T under irradiation of thermal photons with temperature T_r, other than T. The distribution of nonequilibrium electron-hole pairs was obtained for the cases of low and high concentration of carriers. For the case when the interparticle scattering is unessential, the distribution function is determined by the interplay of intraband relaxation of energy due to acoustic phonons and interband radiative transitions caused by the thermal radiation. When the Coulomb scattering dominates, then the quasi-equilibrium distribution with effective temperature and non-equilibrium concentration, determined through balance equations, is realized. Due to the effect of thermal radiation with temperature $T_r\neq T$ concentration and conductivity of carriers in graphene modify essentially. It is demonstrated, that at $T_r>T$ the negative interband absorption, caused by the inversion of carriers distribution, can occur, i.e. graphene can be unstable under thermal irradiation.Comment: 5 pages, 4 figure

Overcoming the uncanny valley: Displays of emotions reduce the uncanniness of humanlike robots

In this paper we show empirically that highly humanlike robots make thoughts of death more accessible, leading to perceptions of uncanniness and eeriness of such robots. Rather than reducing the humanlikeness of robots, our research suggests the addition of emotion displays to decrease a sense of uncanniness. We show that a highly humanlike robot displaying emotions in a social context reduces death-thought accessibility (DTA), which in turn reduces uncanniness. In a pre-test with N = 95 participants, we established that not all humanoid robots elicit thoughts of death and that the extent to which a robot appears humanlike may be linked to DTA. In our Main Study, N = 44 participants briefly interacted with a highly humanlike robotic head that either showed appropriate basic emotions or reacted by blinking. The display of emotions significantly reduced perceptions of uncanniness, which was mediated by a corresponding reduction in DTA. Implications for the design of humanoid robots are proposed.EPSR

Rabi oscillations under ultrafast excitation of graphene

We study coherent nonlinear dynamics of carriers under ultrafast interband excitation of an intrinsic graphene. The Rabi oscillations of response appear with increasing of pumping intensity. The photoexcited distribution is calculated versus time and energy taking into account the effects of energy relaxation and dephasing. Spectral and temporal dependencies of the response on a probe radiation (transmission and reflection coefficients) are considered for different pumping intensities and the Rabi oscillations versus time and intensity are analyzed.Comment: 6 pages, 6 figure