Turnstile slot antenna

A turnstile slot antenna is disclosed, the antenna being for and integral with a spacecraft having a substantially cylindrical body portion. The antenna comprises a circumferential slot about the periphery of the spacecraft body portion with an annular wave guide cavity defining a radial transmission line disposed within the spacecraft body portion behind and in communication with the circumferential slot. Feed stubs and associated transmission apparatus are provided to excite the annular cavity in quadrature phase such that an omnidirectional, circularly polarized, rotating radiation pattern is generated. The antenna of the instant invention has utility both as a transmitting and receiving device, and ensures continuous telemetry and command coverage with the spacecraft

Comparison of experimental and predicted performance of 150-millimeter-bore solid and drilled ball bearings to 3 million DN

Seven 150-millimeter-bore ball bearings were run under 8900-newton (2000-lbf) thrust load at speeds from 6670 to 20,000 rpm (1 million to 3 million DN). Four of the bearings had conventional solid balls, and three bearings had drilled (cylindrically hollow) balls with 50-percent mass reduction. The bearings were under-race cooled and slot lubricated with a type 2 ester oil at flow rates from 4.35 x 0.001 to 5.94 x 0.001 cubic meter/min (1.15 to 1.57 gal/min). Friction torque and temperature were measured on all bearings. While there was considerable spread in the temperature data, the drilled ball bearings tended to run slightly cooler than the solid ball bearings at higher speeds. No significant difference in torque was noted, however, between the solid and drilled ball bearings. One bearing of each type was rerun at 17,800-newton (4000-lbf) thrust load. The solid ball bearings performed satisfactorily at 3 million DN. However, at about 2 million DN the drilled ball bearing experienced a broken ball, and cracks appeared in other balls as a result of flexure fatigue. Metallurgical examination of the cracked balls indicated a brittle structure in the bore of the drilled balls

Dynamic load capacities of graphite fiber: Polyimide composites in oscillating plain bearings to 340 C (650 F)

Load capacities were determined for plain spherical bearings with self-lubricating spherical elements of graphite-fiber-reinforced-polyimide, and for plain cylindrical bearings with thin-wall liners of the composite in the bearing bores. Composites consisted of a 1-to-1 weight ratio of graphite fibers and polyimide. Oscillation was at an amplitude of + or - 15 deg at a frequency of 1 hertz. Bearings with composite ball material had a load capacity of approximately 69 MN/sq m (10 000 psi) at room temperature 25 MN/sq m (3600 psi) at 340 C (650 F). Bearings with thin-wall composite liners had much higher load capacities of 280 MN/sq m (40 000 psi) at room temperature amd 240 MN/sq m (35 000 psi) at 320 C (600 F). Friction coefficients were in the range of 0.12 to 0.19. The addition of 10 wt.% graphite fluoride solid lubricant to the composition of the thin-wall liners reduced friction coefficients into the range of 0.10 to 0.12

Clinical Laboratory Assessment of \u3cem\u3eMycoplasma genitalium\u3c/em\u3e Transcription-Mediated Amplification Using Primary Female Urogenital Specimens

Following analysis of primary cervix, vagina, and first-void female urine specimens for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis via commercial transcription-mediated amplification (TMA), residual material was subjected to Mycoplasma genitalium research-use-only TMA. Representation within a 2,478-specimen retrospective study set was established by comparison to a 6-month audit of clinical C. trachomatis TMA (12,999 specimens) on the basis of the C. trachomatis detection rate, specimen source distribution, clinic location, and age. M. genitalium was detected in 282 (11.4%) patients. This rate was higher than those seen with T. vaginalis (9.0%; P _ 0.005), C. trachomatis (6.2%), and N. gonorrhoeae (1.4%). Positive M. genitalium results were confirmed by repeat testing or alternative-target TMA at a rate of 98.7%. The mean age of the M. genitalium-infected females (24.7 years) was lower than that of the T. vaginalis-infected females (mean, 30.1 years; P\u3c0.0001) and higher than that of the C. trachomatis-infected females (mean, 23.8 years; P_0.003). Of 566 patient encounters positive for at least one sexually transmitted infection (STI), 35.9% exhibited sole detection of M. genitalium (P \u3c 0.0004 versus sole detection of other STI agents) and 26.1% were solely positive for T. vaginalis (P \u3c 0.0002 versus C. trachomatis). The M. genitalium and T. vaginalis detection rates among 755 patients at urban emergency departments were 14.6% and 13.0%, respectively (P _ 0.37). A 10.0% M. genitalium detection rate from other facilities exceeded that of T. vaginalis (7.2%; P _ 0.004). Incorporation of M. genitalium TMA into comprehensive testing programs would detect M. genitalium in a significant proportion of females, particularly those in outpatient obstetrics and gynecology (OB/GYN) settings

Symbolic Interaction and Social Work Supervision

Professions historically have been practiced autonomously, but with the proliferation of professionalism as technology advances professional practice is being conducted more and more within the confines of organizational necessities. There is an inherent conflict between professional autonomy and organizational constraints. This conflict has created a need for theoretical formulations that mediate this situational relationship. The theoretical formulations of Mead, Cooley, Linton, Thomas, Kinch, and Blumer are used to identify a system for taking account of the individual within the organization. Using the concepts of looking glass self, self-indications, role, status, definition of the situation, the social self, scripts, and actors, specific areas of concern for empirical research are identified. An interactionist perspective is used to demonstrate how the professional self-image is derived from specific others in each interactive situation, but at the same time the individual professional practitioner is an active, creative source of behavior. How the professional defines the situation and reconciles self-actions and organization expectations depends to a large extent on how the supervisory process is structured and acted out. Various theorists, their theoretical formulations and the possible research apDlications of each in relation to professional activity within organizations are identified

Applied Sociology and Social Work: Manpower and Theoretical Issues

Applied sociology and social work are compared and contrasted historically. Significant literature is reviewed that illustrates chronologically past cooperative efforts. Academic and practice integration of the two disciplines are identified in their modern context as well as trends are identified. Manpower issues that parallel and separate the two disciplines are explored. It is argued that current changes in funding of educational programs could have much impact on both disciplines and determine future differentiation

Changes In Submersed Macrophytes In Relation To Tidal Storm Surges

We analyzed long-term submersed macrophyte presence-absence data collected from 15 stations in Kings Bay/Crystal River, Florida in relation to three major storm events. The percent occurrence of most species declined immediately after storm events but the recovery pattern after the storm differed among species. Hydrilla (Hydrilla verticillata (L.F.) Royle)and Eurasian watermilfoil (Myriophyllum spicatum L.) exhibited differing recolonization behaviors. Eurasian watermilfoil recolonized quickly after storms but declined in abundance as hydrilla began to increase in abundance. Natural catastrophic events restructure submersed macrophyte communities by eliminating the dominate species, and allowing revegetation and restructuring of communities. Tidal surges may also act to maintain species diversity in the system. In addition, catastrophic events remove dense nuisance plant growth for several years, altering the public's perception of the nuisance plant problem of Kings Bay/Crystal River

Effect of ball geometry on endurance limit in bending of drilled balls

Four designs of drilled (cylindrically hollow) balls were tested for resistance to bending fatigue. Bending fatigue has been demonstrated to be a limiting factor in previous evaluations of the drilled ball concept. A web reinforced drilled ball was most successful in resisting bending fatigue. Another design of through drilled design, involving a heavier wall than the standard reference ball, also showed significant improvement in resistance to bending fatigue

First Experiences Integrating PC Distributed I/O Into Argonne's ATLAS Control System

First Experiences Integrating PC Distributed I/O Into Argonne's ATLAS Control System The roots of ATLAS (Argonne Tandem-Linac Accelerator System) date back to the early 1960s. Located at the Argonne National Laboratory, the accelerator has been designated a National User Facility, which focuses primarily on heavy-ion nuclear physics. Like the accelerator it services, the control system has been in a constant state of evolution. The present real-time portion of the control system is based on the commercial product Vsystem [1]. While Vsystem has always been capable of distributed I/O processing, the latest offering of this product provides for the use of relatively inexpensive PC hardware and software. This paper reviews the status of the ATLAS control system, and describes first experiences with PC distributed I/O.Comment: ICALEPCS 2001 Conference, PSN WEAP027, 3 pages, 1 figur

Theoretical Design and Analysis of Multivolume Digital Assays with Wide Dynamic Range Validated Experimentally with Microfluidic Digital PCR

This paper presents a protocol using theoretical methods and free software to design and analyze multivolume digital PCR (MV digital PCR) devices; the theory and software are also applicable to design and analysis of dilution series in digital PCR. MV digital PCR minimizes the total number of wells required for “digital” (single molecule) measurements while maintaining high dynamic range and high resolution. In some examples, multivolume designs with fewer than 200 total wells are predicted to provide dynamic range with 5-fold resolution similar to that of single-volume designs requiring 12 000 wells. Mathematical techniques were utilized and expanded to maximize the information obtained from each experiment and to quantify performance of devices and were experimentally validated using the SlipChip platform. MV digital PCR was demonstrated to perform reliably, and results from wells of different volumes agreed with one another. No artifacts due to different surface-to-volume ratios were observed, and single molecule amplification in volumes ranging from 1 to 125 nL was self-consistent. The device presented here was designed to meet the testing requirements for measuring clinically relevant levels of HIV viral load at the point-of-care (in plasma, 1 000 000 molecules/mL), and the predicted resolution and dynamic range was experimentally validated using a control sequence of DNA. This approach simplifies digital PCR experiments, saves space, and thus enables multiplexing using separate areas for each sample on one chip, and facilitates the development of new high-performance diagnostic tools for resource-limited applications. The theory and software presented here are general and are applicable to designing and analyzing other digital analytical platforms including digital immunoassays and digital bacterial analysis. It is not limited to SlipChip and could also be useful for the design of systems on platforms including valve-based and droplet-based platforms. In a separate publication by Shen et al. (J. Am. Chem. Soc., 2011, DOI: 10.1021/ja2060116), this approach is used to design and test digital RT-PCR devices for quantifying RNA