Coaxial prime focus feeds for paraboloidal reflectors

A TE11 - TM11 dual mode coaxial feed for use in prime focus paraboloidal antenna systems is investigated. The scattering matrix parameters of the internal bifurcation junction was determined by the residue calculus technique. The scattering parameters and radiation fields of the aperture were found from the Weinstein solution. The optimum modeing ratio for minimum cross-polarization was determined along with the corresponding optimum feed dimensions. A peak cross-polarization level of -58 dB is predicted. The frequency characteristics were also investigated and a bandwidth of 5% is predicted over which the cross-polarization remains below -30 dB, the input VSWR is below 1.15, and the phase error is less than 10 deg. Theoretical radiation patterns and efficiency curves for a paraboloidal reflector illuminated by this feed were computed. The predicted sidelobe level is below -30 dB and aperture efficiencies greater than 70% are possible. Experimental results are also presented that substantiates the theoretical results. In addition, experimental results for a 'short-cup' coaxial feed are given. The report includes extensive design data for the dual-mode feed along with performance curves showing cross-polarization as a function of feed parameters. The feed is useful for low-cost ground based receiving antennas for use in direct television satellite broadcasting service

Transforming Transsexual and Transgender Rights

State and federal employment anti-discrimination statutes have failed to adequately protect transsexual and transgendered individuals in the workplace. Although advancements have been made in recent years regarding the protection of sexual minorities, transsexual and transgendered employees continue to receive sporadic and noncomprehensive protection. Various approaches have been taken to extend protection against discrimination to these individuals, including the utilization of disability protection statutes, the expansion of anti-discrimination statutes, and the protection of transsexual and transgendered individuals as a class; however, these approaches have proven flawed in providing adequate protection. An examination of anti-discrimination law shows that these measures, while perhaps desirable, are not necessary to protect transsexual and transgendered persons. This Article argues that existing legislation already provides a basis for protecting these minorities. That is, courts should recognize discrimination against transsexual and transgendered individuals as classic sex discrimination under Title VII of the Civil Rights Act of 1964 and corresponding state anti-discrimination statutes

SOFIP: A Short Orbital Flux Integration Program

A computer code was developed to evaluate the space radiation environment encountered by geocentric satellites. The Short Orbital Flux Integration Program (SOFIP) is a compact routine of modular compositions, designed mostly with structured programming techniques in order to provide core and time economy and ease of use. The program in its simplest form produces for a given input trajectory a composite integral orbital spectrum of either protons or electrons. Additional features are available separately or in combination with the inclusion of the corresponding (optional) modules. The code is described in detail, and the function and usage of the various modules are explained. A program listing and sample outputs are attached

Millimeter wave transmission systems and related devices

A survey was made of the state-of-the-art in millimeter (20 GHz to 300 GHz) wave transmission systems and related devices. The survey includes summaries of analytical studies and theoretical results that were obtained for various transmission line structures. This material was supplemented by further analysis where appropriate. The transmission line structures are evaluated in terms of electrical performance, ease of manufacture, usefulness for building other devices and compatibility with solid state devices. Descriptions of waveguide transmission lines which have commonly been used in the microwave frequency range are provided along with special attention given to the problems that these guides face when their use is extended into the millimeter wave range. Also, guides which have been introduced specifically to satisfy the requirements of millimeter wave transmission are discussed in detail

Penetration and cratering experiments of graphite by 0.5-mm diameter steel spheres at various impact velocities

Cratering experiments have been conducted with 0.5-mm diameter AISI 52100 steel spherical projectiles and 30-mm diameter, 15-mm long graphite targets. The latter were made of a commercial grade of polycrystalline and porous graphite named EDM3 whose behavior is known as macroscopically isotropic. A two-stage light-gas gun launched the steel projectiles at velocities between 1.1 and 4.5 km s 1. In most cases, post-mortem tomographies revealed that the projectile was trapped, fragmented or not, inside the target. It showed that the apparent crater size and depth increase with the impact velocity. This is also the case of the crater volume which appears to follow a power law significantly different from those constructed in previous works for similar impact conditions and materials. Meanwhile, the projectile depth of penetration starts to decrease at velocities beyond 2.2 km s 1. This is firstly because of its plastic deformation and then, beyond 3.2 km s 1, because of its fragmentation. In addition to these three regimes of penetration behavior already described by a few authors, we suggest a fourth regime in which the projectile melting plays a significant role at velocities above 4.1 km s 1. A discussion of these four regimes is provided and indicates that each phenomenon may account for the local evolution of the depth of penetration

I Did it For Me: Negotiating identity and agency

Scholars have debated the feminist critique of female beauty practices for years with the fundamental disagreement revolving around the notion of “agency.” This study used textual analysis to explore how the concept of “agency” has been employed in cosmetic surgery ads placed in large city magazines.   Three themes emerged: realize your potential, pleasing yourself, and control your destiny.  This research expands our understanding of how physicians are repositioning cosmetic surgery to women through discourses that empower, appeal to their sense of self, and play upon feminist sensibilities that privilege individual choice. This research also contributes to the literature surrounding the ongoing debate of agency by examining how it plays out in another form of text previously unexamined (physician advertising) and how it touches upon a new player in the health beauty system (physicians) rather than prior studies, which focus on idealized images in the media