Circular 21

Developed from the hybrid Diamond x Khogot by the Alaska Agricultural Experiment Station, Gasser wheat was released to seed producers in 1955. This variety exhibits an excellent combination of high yield and agronomic desirability m Alaska. It is superior to the standard variety Khogot in lodging resistance, shattering resistance, and grain quality. Gasser wheat is not satisfactory for commercial milling and baking. Its chief value in Alaska will be as a feed for poultry and livestock. Gasser is recommended for production in the Matanuska and Tanana Valleys when a wheat crop is desired. Later maturing than other cereals, Gasser must be planted early to insure maturity during the short growing season. Cultural recommendations are the same as for other cereals.In cooperation with the United States Department of Agricultur

Cooperative Relaying with CPFSK and Distributed Space-Time Trellis Codes

Cooperative relaying allows single antenna users to achieve diversity and coding gains by utilizing nearby users' transmitting capabilities. We consider a relay system employing constant envelope continuous phase frequency shift keying. Distributed space-time trellis codes are implemented with a novel multiple relay protocol

Cooperative Relaying with CPFSK and Distributed Space-Time Trellis Codes

Cooperative relaying allows single antenna users to achieve diversity and coding gains by utilizing nearby users' transmitting capabilities. We consider a relay system employing constant envelope continuous phase frequency shift keying. Distributed space-time trellis codes are implemented with a novel multiple relay protocol

Non-linear finite element formulation applied to thermoelectric materials under hyperbolic heat conduction model

In the present work, a three-dimensional, dynamic and non-linear finite element to simulate thermoelectric behavior under a hyperbolic heat conduction model is presented. The transport equations, which couple electric and thermal energies by the Seebeck, Peltier and Thomson effects, are analytically obtained through extended non-equilibrium thermodynamics, since the local equilibrium hypothesis is not valid under the hyperbolic model. In addition, unidimensional analytical solutions are obtained to validate the finite element formulation. Numerically, isoparametric eight-node elements with two degrees of freedom (voltage and temperature) per node are used. Non-linearities due to the temperature-dependence on the transport properties and the Joule effects are addressed with the Newton-Raphson algorithm. For the dynamic problem, HHT and Newmark-ß algorithms are compared to obtain accurate results, since numerical oscillations (Gibbs phenomena) are present when the initial boundary conditions are discontinuous. The last algorithm, which is regularized by relating time steps and element sizes, provides the best results. Finally, the finite element implementation is validated, comparing the analytical and the numerical solutions, and a three-dimensional example is presented.This research was partially supported by the Spanish Ministry of Education through Grant No. FPU AP-2006-02372 and also from Grants MICINN BIA-2008-00522, CSD2008-00037 Canfranc Under-ground Physics, Excelencia Junta Andalucia P08-TEP-03641 and "Ayudas Investigacion" from UPV. The authors would also like to thank Prof. Guillermo Rus for his valuable contributions.Palma, R.; Pérez-Aparicio, JL.; Taylor, R. (2012). Non-linear finite element formulation applied to thermoelectric materials under hyperbolic heat conduction model. Computer Methods in Applied Mechanics and Engineering. 213-216:93-103. https://doi.org/10.1016/j.cma.2011.11.011S93103213-21

Automated surgical screwdriver: automated screw placement

The use of power screwdrivers and drills for tapping and screw insertion in surgery is becoming more common. It has been established from clinical observations that the use of a small air drill for inserting self-tapping screws provides improved coaxial alignment and precision, and that the drill should be stopped before the screw head is completely seated on the plate, presumably to reduce the risk of over-tightening. The risk of overrun and over-tightening during tapping and screw insertion is increased with the use of power tools. Prevention of over-tightening is dependent upon when the surgeon detects the onset of tightening, both visually and from the feel of the rapid increase in torque. If detection is too late, then over-tightening or stripping can occur. This study is concerned with using a mechatronic screwdriver to control the tapping depth and to prevent the over-tightening of screws. The effects of various parameters upon the torque profile during tapping and screw insertion have been investigated in synthetic bone and sheep tibia. An automated system is proposed for preventing over-tightening of pre-tapped and self-tapping screws when attaching a surgical plate to a sheep tibia in vitro. The system was used to attach a plate to a sheep tibia using self-tapping screws. The mean torque of the screws inserted using the automated system was 35 per cent of the stripping torque

A stabilized finite point method for analysis of fluid mechanics problems

flow type problems is presented. The method is based on the use of a weighted least square interpolation procedure together with point collocation for evaluating the approximation integrals. Some examples of application to convective trasport and compressible flow problems are presented

Dimensional Changes in Dental Stone and Plaster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66786/2/10.1177_00220345500290060601.pd

MeV ion beam induced index of refraction changes in layered GaAs/AlGaAs waveguides

Previously, we showed that localized optical modifications could be produced without subsequent post thermal annealing in selectively masked planar GaAs/Al{sub .4}Ga{sub .6}As waveguide structures using 10 MeV oxygen ions. In our present investigation, irradiation experiments were performed on masked GaAs/Al{sub .4}Ga{sub .6}As waveguide samples at 298 K using 10 MeV oxygen and 8 MeV carbon ions. The two ion incident energies were chosen to yield the maximum electronic stopping power near the interface separating the top cladding layer and the guiding layer. This localized modification process emphasizes the crucial role that the electronic energy transfer plays on the degree to which the refractive index of the guiding layer is altered. Propagation loss measurements on the fabricated channel waveguides were performed by end fire coupling a laser diode source at a wavelength of 1.3 {mu}m. Observation of the extracted propagation loss values reveal that further optimization of the ion beam parameters are required before practical applications can be achieved. The relative efficiency of the various ions to induce optically altered regions which serve as lateral confinement barriers of laser light shows that this fabrication process is sensitive to the ion beam current