The Linear Polarization of Sagittarius A* II. VLA and BIMA Polarimetry at 22, 43 and 86 GHz

We present a search for linear polarization at 22 GHz, 43 GHz and 86 GHz from the nearest super massive black hole candidate, Sagittarius A*. We find upper limits to the linear polarization of 0.2%, 0.4% and 1%, respectively. These results strongly support the conclusion of our centimeter wavelength spectro-polarimetry that Sgr A* is not depolarized by the interstellar medium but is in fact intrinsically depolarized.Comment: Accepted for publication in ApJ, 13 pages, 2 figure

Brief Note Elemental Analysis of Biological Material in the Fresh-Frozen State

Author Institution: Department of Zoology and Department of Surgery, The Ohio State Universit

A Scalable Correlator Architecture Based on Modular FPGA Hardware, Reuseable Gateware, and Data Packetization

A new generation of radio telescopes is achieving unprecedented levels of sensitivity and resolution, as well as increased agility and field-of-view, by employing high-performance digital signal processing hardware to phase and correlate large numbers of antennas. The computational demands of these imaging systems scale in proportion to BMN^2, where B is the signal bandwidth, M is the number of independent beams, and N is the number of antennas. The specifications of many new arrays lead to demands in excess of tens of PetaOps per second. To meet this challenge, we have developed a general purpose correlator architecture using standard 10-Gbit Ethernet switches to pass data between flexible hardware modules containing Field Programmable Gate Array (FPGA) chips. These chips are programmed using open-source signal processing libraries we have developed to be flexible, scalable, and chip-independent. This work reduces the time and cost of implementing a wide range of signal processing systems, with correlators foremost among them,and facilitates upgrading to new generations of processing technology. We present several correlator deployments, including a 16-antenna, 200-MHz bandwidth, 4-bit, full Stokes parameter application deployed on the Precision Array for Probing the Epoch of Reionization.Comment: Accepted to Publications of the Astronomy Society of the Pacific. 31 pages. v2: corrected typo, v3: corrected Fig. 1

Reliability analysis of single crystal NiAl turbine blades

As part of a co-operative agreement with General Electric Aircraft Engines (GEAE), NASA LeRC is modifying and validating the Ceramic Analysis and Reliability Evaluation of Structures algorithm for use in design of components made of high strength NiAl based intermetallic materials. NiAl single crystal alloys are being actively investigated by GEAE as a replacement for Ni-based single crystal superalloys for use in high pressure turbine blades and vanes. The driving force for this research lies in the numerous property advantages offered by NiAl alloys over their superalloy counterparts. These include a reduction of density by as much as a third without significantly sacrificing strength, higher melting point, greater thermal conductivity, better oxidation resistance, and a better response to thermal barrier coatings. The current drawback to high strength NiAl single crystals is their limited ductility. Consequently, significant efforts including the work agreement with GEAE are underway to develop testing and design methodologies for these materials. The approach to validation and component analysis involves the following steps: determination of the statistical nature and source of fracture in a high strength, NiAl single crystal turbine blade material; measurement of the failure strength envelope of the material; coding of statistically based reliability models; verification of the code and model; and modeling of turbine blades and vanes for rig testing

The Ursinus Weekly, October 14, 1976

Ursinus news in brief: Parsons admitted to Sacred Heart ; Reiner, Bozorth receive awards; Grant supports psych research; Staskiel to make TV debut • Freshmen elect officers • Nine join faculty • USGA holds carnival • Economics club meets • Ursinus and the arts • Another look at alumni • Coming campus events • WPAZ offers intern program • Harriers surging • LV, Johns Hopkins beat Karas\u27 Bears • Sixers: ready for all new NBA • Saturday\u27s gamehttps://digitalcommons.ursinus.edu/weekly/1058/thumbnail.jp

The Ursinus Weekly, March 3, 1977

Ursinus news in brief: Weekly begins new feature; Constitutions approved; Honor society holds seminar; Pre-legal meets • SFARC year in review • USGA president offers comments • Ass\u27t dean interviewed • Comment: Investigation demanded; Our time to speak • Weekly special • Letters to the editor: More on food; Review reply; A non-sports fan speaks • Rumours • Beachcombers • Swimmers are 2nd, 6th; Wrestlers 8th • Handwerk resigns after Bears win first game • Macs bury Bears • Brighter football future aheadhttps://digitalcommons.ursinus.edu/weekly/1067/thumbnail.jp

The Ursinus Weekly, November 4, 1976

Ursinus news in brief: S.F.A.R.C. approves letter; Ursinus to install new President; Schwalm invites students; Temple U. presents Brecht • Alarms, finance discussed • U.S.G.A. meets • Law professionals hosted • Comment: Why more trees? • Plant talk • Letter to the editor: Rules blasted • Photo concert • Bause files for patent • Marathon man • Harriers win one of three • Widener rips Bears • Hockey wins continue • Soccer loses twohttps://digitalcommons.ursinus.edu/weekly/1061/thumbnail.jp

The Ursinus Weekly, October 21, 1976

Ursinus news in brief: Parsons recovering; Damage fines abolished; Young Democrats revived; Homecoming planned; Voter registration held; MBA fair planned • Messiah cut back • Placement meetings set • Commuters organize • SAC reports • Comment: The ugly American lives on • Richter talks to freshmen • Comment: Alumni-student relations • Rheinpfalz folk culture • Bob Dean: Artist • proTheatre produces one acts • Beautiful noise • Operation: White Cloud • Coming campus events • Handwerk replaces Fry • Soccer drops three • Bears lose • X-Country splits • Kang\u27s return • McGinnis views NBA and Sixershttps://digitalcommons.ursinus.edu/weekly/1059/thumbnail.jp

The Precision Array for Probing the Epoch of Reionization: 8 Station Results

We are developing the Precision Array for Probing the Epoch of Reionization (PAPER) to detect 21cm emission from the early Universe, when the first stars and galaxies were forming. We describe the overall experiment strategy and architecture and summarize two PAPER deployments: a 4-antenna array in the low-RFI environment of Western Australia and an 8-antenna array at our prototyping site in Green Bank, WV. From these activities we report on system performance, including primary beam model verification, dependence of system gain on ambient temperature, measurements of receiver and overall system temperatures, and characterization of the RFI environment at each deployment site. We present an all-sky map synthesized between 139 MHz and 174 MHz using data from both arrays that reaches down to 80 mJy (4.9 K, for a beam size of 2.15e-5 steradians at 154 MHz), with a 10 mJy (620 mK) thermal noise level that indicates what would be achievable with better foreground subtraction. We calculate angular power spectra ($C_\ell$) in a cold patch and determine them to be dominated by point sources, but with contributions from galactic synchrotron emission at lower radio frequencies and angular wavemodes. Although the cosmic variance of foregrounds dominates errors in these power spectra, we measure a thermal noise level of 310 mK at $\ell=100$ for a 1.46-MHz band centered at 164.5 MHz. This sensitivity level is approximately three orders of magnitude in temperature above the level of the fluctuations in 21cm emission associated with reionization.Comment: 13 pages, 14 figures, submitted to AJ. Revision 2 corrects a scaling error in the x axis of Fig. 12 that lowers the calculated power spectrum temperatur