FACTORS INFLUENCING RATES OF ADOPTION OF TRICHOMONIASIS VACCINE BY NEVADA RANGE CATTLE PRODUCERS

Tritrichimonas foetus vaccine has been marketed since 1989 to combat the trichomoniasis disease that causes reproductive failure and considerable economic loss to Nevada ranchers. An ex post technology adoption model is estimated to examine the possible adoption rate, to identify the factors that may influence the adoption behavior, and to test how the probability of adoption for five possible adopter groups would change due to changes in various ranch specific factors. Results indicate that use of computers, veterinary checkup of herd, and herd size influence the probability of adoption. Model results show that cooperative extension programs enhance the rate of adoption.Livestock Production/Industries,

Highly Integrated Steam Reforming Fuel Processor with Condensing Burner Technology for Maximised Electrical Efficiency of CHP-PEMFC Systems

AbstractCompact fuel processors using natural gas, LPG and biogas for μCHP fuel cell systems have been developed at ZBT for over 10 years. The technology, based on steam reforming, includes a reformer and a WGS reactor, a water evaporator, heat exchangers and a fuel/anodic offgas burner integrated in an insulated housing. For coupling with a LT-PEMFC today an external preferential oxidation or methanation is added. A HT-PEMFC can be coupled directly to the fuel processor at a temperature level of 160°C. It is discussed that HT-PEMFC systems can exceed the electrical efficiency of LT-PEMFC systems up to five percentage points because of the integration of high quality heat from the fuel cell cooling cycle. In process simulations with AspenPlus® this efficiency advantage could be confirmed. But further investigations concerning heat integration showed for both systems the advantage of using the condensation enthalpy of the flue gas provided by the system burner. This gain in energy offers the opportunity to realise burner operation only with anodic offgas, without additional fuel firing. This study shows the use of condensing burner technology in the fuel processor in comparison of integrating HT-PEMFC heat and/or the use of conventional low-temperature burner technology. For comparison the system boundaries and efficiencies were clearly determined. Heat sources and sinks were identified and quantified along the process chain of steam reforming. A pinch analysis illustrates the requirement of additional heat flows concerning their power and temperature levels

Novel concept of multi-channel fiber optic surface plasmon resonance sensor

A novel multi-channel fiber optic surface plasmon resonance (SPR) sensor is reported. The sensing structure consists of a single-mode optical fiber, covered with a thin gold layer, which supports a surface plasmon (SP), and a Bragg grating. The Bragg grating induces coupling between the forward-propagating fundamental core mode and the back-propagating SP-cladding mode. As the SP-cladding modes are highly sensitive to changes in the refractive index of the surrounding medium, the changes can be accurately measured by spectroscopy of these hybrid modes. Multichannel capability is achieved by employing a sequence of Bragg gratings of different periods and their reading via the wavelength division multiplexing. Theoretical analysis and optimization based on the coupled-mode theory (CMT) is carried out and performance characteristics of the sensor are determined

Long-distance rail in Europe: Comparing the forms of head-on competition across Europe

Europe is finally entering a season of liberalisation in the long-distance rail passenger market, which takes the form of on-track competition among public and private operators. The paper provides a broad-scope comparison of relevant European markets, belonging to liberalised and non-liberalised countries, aiming to point out the patterns in terms of supply, competition model and prices. The paper is based on a sample of heterogeneous 69 city-pairs, analysed in two fourteen days periods in 2019 (May/June and November). All available modes are observed, collecting info on companies, frequency of services, and cheapest price. The analysis starts from a schematisation of different business models, based on literature. Then, using the database, we study the country's supply structure, size, and level of intermodal and intra-modal competition through HHIs. Prices are analysed in two steps: the average prices and the price dispersion, searching for their main determinants, including but not limited to competition. Results show that a higher competition level is not always corresponding to low prices, which are instead determined by many other factors such as size of market, demand, socio-economic characteristics, subsidies, production costs, speed advantage, strength of the incumbent, etc. The competition level, instead, directly influences the quality, the supplied capacity, and the price dispersion

The effect of Coulomb interaction at ferromagnetic-paramagnetic metallic perovskite junctions

We study the effect of Coulomb interactions in transition metal oxides junctions. In this paper we analyze charge transfer at the interface of a three layer ferromagnetic-paramagnetic-ferromagnetic metallic oxide system. We choose a charge model considering a few atomic planes within each layer and obtain results for the magnetic coupling between the ferromagnetic layers. For large number of planes in the paramagnetic spacer we find that the coupling oscillates with the same period as in RKKY but the amplitude is sensitive to the Coulomb energy. At small spacer thickness however, large differences may appear as function of : the number of electrons per atom in the ferromagnetics and paramagnetics materials, the dielectric constant at each component, and the charge defects at the interface plane emphasizing the effects of charge transfer.Comment: tex file and 7 figure

Cancellation of probe effects in measurements of spin polarized momentum density by electron positron annihilation

Measurements of the two dimensional angular correlation of the electron-positron annihilation radiation have been done in the past to detect the momentum spin density and the Fermi surface. We point out that the momentum spin density and the Fermi Surface of ferromagnetic metals can be revealed within great detail owing to the large cancellation of the electron-positron matrix elements which in paramagnetic multiatomic systems plague the interpretation of the experiments. We prove our conjecture by calculating the momentum spin density and the Fermi surface of the half metal CrO2, who has received large attention due to its possible applications as spintronics material

Topological insulators in the quaternary chalcogenide compounds and ternary famatinite compounds

We present first-principles calculations to predict several three dimensional (3D) topological insulators in quaternary chalcogenide compounds which are made of I$_2$-II-IV-VI$_4$ compositions and in ternary compositions of I$_3$-V-VI$_4$ famatinite compounds. Among the large members of these two families, we give examples of naturally occurring compounds which are mainly Cu-based chalcogenides. We show that these materials are candidates of 3D topological insulators or can be tuned to obtain topological phase transition by manipulating the atomic number of the other cation and anion elements. A band inversion can occur at a single point $\Gamma$ with considerably large inversion strength, in addition to the opening of a bulk band gap throughout the Brillouin zone. We also demonstrate that both of these families are related to each other by cross-substitutions of cations in the underlying tetragonal structure and that one can suitably tune their topological properties in a desired manner.Comment: 7 pages, 4 figure

Electronic structure of the ferromagnetic superconductor UCoGe from first principles

The superconductor UCoGe is analyzed with electronic structure calculations using Linearized Augmented Plane Wave method based on Density Functional Theory. Ferromagnetic and antiferromagnetic calculations with and without correlations (via LDA+U) were done. In this compound the Fermi level is situated in a region where the main contribution to DOS comes from the U-5f orbital. The magnetic moment is mainly due to the Co-3d orbital with a small contribution from the U-5f orbital. The possibility of fully non-collinear magnetism in this compound seems to be ruled out. These results are compared with the isostructural compound URhGe, in this case the magnetism comes mostly from the U-5f orbital