Shortened horn-reflector antenna

A shortened horn-reflector antenna overcomes the mechanical disadvantages and complexity of the conventional horn-reflector antenna. The shortened antenna offers broadband performance, economic construction, very low antenna temperature, and excellent pattern performance

NiO Exchange Bias Layers Grown by Direct Ion Beam Sputtering of a Nickel Oxide Target

A new process for fabricating NiO exchange bias layers has been developed. The process involves the direct ion beam sputtering (IBS) of a NiO target. The process is simpler than other deposition techniques for producing NiO buffer layers, and facilitates the deposition of an entire spin-valve layered structure using IBS without breaking vacuum. The layer thickness and temperature dependence of the exchange field for NiO/NiFe films produced using IBS are presented and are similar to those reported for similar films deposited using reactive magnetron sputtering. The magnetic properties of highly textured exchange couples deposited on single crystal substrates are compared to those of simultaneously deposited polycrystalline films, and both show comparable exchange fields. These results are compared to current theories describing the exchange coupling at the NiO/NiFe interface.Comment: 9 pages, Latex 2.09, 3 postscript figures. You can also this manuscript at http://www.wsrcc.com/alison/fixed-nio/manuscript.html To be published in _IEEE Trans. Magn._, Nov. 199

Triple redundant hydrogen sensor with in situ calibration

To meet sensing and calibration needs, an in situ calibration technique was developed. It is based on electrolytic generation of a hydrogen/air atmosphere within a hydrogen sensor. The hydrogen is generated from water vapor in the air, and being electrical in nature, the in situ calibration can be performed completely automatically in remote locations. Triply redundant sensor elements are integrated within a single, compact housing, and digital logic provides inter-sensor comparisons to warn of and identify malfunctioning sensor elements. An evaluation of this concept is presented

Private Institutions Collaborate in Implementing Senate Bill 1 Initiatives

Funds were made available to each of our institutions, Campbellsville University, Lindsey Wilson College, and St. Catherine College through the Association of Independent Kentucky Colleges and Universities for faculty training for the implementation of Senate Bill 1. By pooling the funds available to each of our institutions, we designed a Senate Bill 1 Symposium, an initial six-hour workshop to introduce Senate Bill 1, tailored to the needs of our institutions that provided rich resources and a quality experience. From the core of faculty trained at the initial workshop, each institution was able to build additional training for faculty and to begin the implementation of Senate Bill 1. Working together, we create a cross-fertilization of ideas and a set of contacts for resources that strengthen not only the quality of our professional development, but also present a model for collaboration that provides smaller programs the opportunity to implement quality training. Having the resources to design an initial quality professional development event to meet the specific needs of our faculty members set the stage for our faculty to benefit from subsequent training since our workshop was the first among the private institutions and one of the first in the state

Bayesian photon counting with electron-multiplying charge coupled devices (EMCCDs)

The EMCCD is a CCD type that delivers fast readout and negligible detector noise, making it an ideal detector for high frame rate applications. Because of the very low detector noise, this detector can potentially count single photons. Considering that an EMCCD has a limited dynamical range and negligible detector noise, one would typically apply an EMCCD in such a way that multiple images of the same object are available, for instance, in so called lucky imaging. The problem of counting photons can then conveniently be viewed as statistical inference of flux or photon rates, based on a stack of images. A simple probabilistic model for the output of an EMCCD is developed. Based on this model and the prior knowledge that photons are Poisson distributed, we derive two methods for estimating the most probable flux per pixel, one based on thresholding, and another based on full Bayesian inference. We find that it is indeed possible to derive such expressions, and tests of these methods show that estimating fluxes with only shot noise is possible, up to fluxes of about one photon per pixel per readout.Comment: Fixed a few typos compared to the published versio

Visuality without form: video-mediated communication and research practice across disciplinary contexts

Visuality is a concept that crosses boundaries of practice and meaning, making it an ideal subject for interdisciplinary research. In this article, we discuss visuality using a fragment from a video meeting of television producers at Swedish Television’s group for programming in Swedish Sign Language. This example argues for the importance of recognizing the diversity of analytical and practice-derived visualities and their effect on the ways in which we interpret cultures. These different visualities have consequences for the methods and means with which we present scholarly research. The role of methods, methodology, and analysis of visual practices in an organizational and bilingual setting are key. We explore the challenges of incorporating deaf visualities, hearing visualities, and different paradigms of interdisciplinary research as necessary when visibility, invisibility, and their materialities are of concern. We conclude that in certain contexts, breaking with disciplinary traditions makes visible that which is otherwise invisible

Energy Conservation and Gravity Waves in Sound-proof Treatments of Stellar Interiors: Part I Anelastic Approximations

Typical flows in stellar interiors are much slower than the speed of sound. To follow the slow evolution of subsonic motions, various sound-proof equations are in wide use, particularly in stellar astrophysical fluid dynamics. These low-Mach number equations include the anelastic equations. Generally, these equations are valid in nearly adiabatically stratified regions like stellar convection zones, but may not be valid in the sub-adiabatic, stably stratified stellar radiative interiors. Understanding the coupling between the convection zone and the radiative interior is a problem of crucial interest and may have strong implications for solar and stellar dynamo theories as the interface between the two, called the tachocline in the Sun, plays a crucial role in many solar dynamo theories. Here we study the properties of gravity waves in stably-stratified atmospheres. In particular, we explore how gravity waves are handled in various sound-proof equations. We find that some anelastic treatments fail to conserve energy in stably-stratified atmospheres, instead conserving pseudo-energies that depend on the stratification, and we demonstrate this numerically. One anelastic equation set does conserve energy in all atmospheres and we provide recommendations for converting low-Mach number anelastic codes to this set of equations.Comment: Accepted for publication in ApJ. 20 pages emulateapj format, 7 figure

The home lawn

A well-graded, fresh, green lawn is the first requirement for the home grounds planting. A fine lawn gives the family physical comfort. We often get our most satisfying relaxation on a soft, cool, well-kept lawn. Every family can have a good lawn by following the simple directions given in this bulletin. You reap what you put into the lawn at the beginning. A properly made lawn will cost you less money to maintain. It is very important that thought be given to the proposed lawn area from the standpoint of soil drainage, organic matter content and fertility. Above all, start with a good soil foundation. Then select an approved grass seed mixture and do the seeding at the right time

A neutrino-nucleon interaction generator for the FLUKA Monte Carlo code

Event generators that handle neutrino-nucleon interaction have been developed for the FLUKA code [1]. In earlier FLUKA versions only quasi-elastic (QEL) interactions were included, and the code relied on external event generators for the resonance (RES) and deep inelastic scattering (DIS). The new DIS+RES event generator is fully integrated in FLUKA and uses the same hadronization routines as those used for simulating hadron-nucleon interactions. Nuclear effects in neutrino-nucleus interactions are simulated within the same framework as in the FLUKA hadron-nucleus interaction model (PEANUT), thus profiting from its detailed physics modelling and longstanding benchmarking. The generators are available in the standard FLUKA distribution. They are presently under development and several improvements are planned to be implemented. The physics relevant to the neutrino-nucleon interactions and the results of comparisons with experimental data are discussed