Sensing circuits for multiwire proportional chambers

Integrated sensing circuits were designed, fabricated, and packaged for use in determining the direction and fluence of ionizing radiation passing through a multiwire proportional chamber. CMOS on sapphire was selected because of its high speed and low power capabilities. The design of the proposed circuits is described and the results of computer simulations are presented. The fabrication processes for the CMOS on sapphire sensing circuits and hybrid substrates are outlined. Several design options are described and the cost implications of each discussed. To be most effective, each chip should handle not more than 32 inputs, and should be mounted on its own hybrid substrate

Ba & Eu Abundances in M15 giant stars

To investigate the Ba and Eu abundances for a sample of 63 giant stars in the globular cluster M15. This is the largest sample of M15 giants stars for which Ba abundances have been determined and, due to the target selection of the original research programme, the Ba abundances are complete along the red giant branch. Stellar parameters were taken from the previous key study and a microturbulence-surface gravity relation was determined for precise measurement of the Ba line at 6496.898 Angstroms, which has a high sensitivity to microturbulence. Element abundances for Ba, La, Eu, Ca, Ni and Fe were calculated using spectrum synthesis and equivalent widths techniques. A bimodal distribution in Ba, Eu and La abundances was found within the sample. The low Ba,Eu,La mode had mean abundances of =-2.41+/-0.16, =-1.80+/-0.08 and =-2.19+/-0.13 while the high Ba,Eu,La mode had mean abundances of =-2.00+/-0.16, =-1.65+/-0.13 and =-1.95+/-0.11. Both modes are indicative of a pollution scenario dominated by the r-process, hence contributions from explosive nucleosynthesis of massive stars. There may be evidence of further enhancement by another heavy element process and of potential anticorrelations in Na-O for both modes indicating a complex formation and evolution history for M15.Comment: 20 pages, 15 figure

Differential chemical abundance analysis of a 47 Tuc AGB star with respect to Arcturus

This study resolves a discrepancy in the abundance of Zr in the 47 Tucanae asymptotic giant branch star Lee 2525. This star was observed using the echelle spectrograph on the 2.3 m telescope at Siding Spring Observatory. The analysis was undertaken by calibrating Lee 2525 with respect to the standard giant star Arcturus. This work emphasises the importance of using a standard star with stellar parameters comparable to the star under analysis rather than a calibration with respect to the Sun (Koch & McWilliam 2008). Systematic errors in the analysis process are then minimised due to the similarity in atmospheric structure between the standard and programme stars. The abundances derived for Lee 2525 were found to be in general agreement with the Brown & Wallerstein (1992) values except for Zr. In this study Zr has a similar enhancement ([Zr/Fe] = +0.51 dex) to another light s-process element, Y ([Y/Fe] = +0.53 dex), which reflects current theory regarding the enrichment of s-process elements by nuclear processes within AGB stars (Busso et al. 2001). This is contrary to the results of Brown & Wallerstein (1992) where Zr was under-abundant ([Zr/Fe] = +0.51 dex) and Y was over-abundant ([Y/Fe] = +0.50 dex) with respect to Fe.Comment: 11 pages, 5 figures Accepted for publication in MNRA

Structural control interaction

The basic guidance and control concepts that lead to structural control interaction and structural dynamic loads are identified. Space vehicle ascent flight load sources and the load relieving mechanism are discussed, along with the the characteristics and special problems of both present and future space vehicles including launch vehicles, orbiting vehicles, and the Space Shuttle flyback vehicle. The special dynamics and control analyses and test problems apparent at this time are summarized

Skeletochronological Study of Adult Spiny Softshell Turtles (Apalone spinifera) from Northeastern Arkansas

Skeletochronological techniques were used to examine age and growth in adult spiny softshell turtles {Apalone spiniferd) from northeastern Arkansas. The diaphyseal region offemurs of 24 specimens (8 mars mars; 16 venus venus) was excised, decalcified in weak hydrochloric acid, and histologically prepared for light microscopy. Skeletal growth was determined from histosectioned bones by measuring femur diameters as well as by counting lines of arrested growth (LAGs) that appear between distinct periosteal layers (marks of skeletal growth =MSGs) laid down during a single growing season. Although significant positive correlations were found between carapace length (CL) and femur diameter in both males and females (r= 0.75; 0.92, respectively), correlation coefficients generated between CL and LAGs (r= 0.30; 0.45, respectively) were not significant. Sources of variation in counts of LAGs include endosteal resorption and remodeling, the lack of visible growth layers, the presence of accessory LAGs, and the compaction of MSGs; this variability introduces sampling error and diminishes the value of this technique as a method of aging adult softshell turtles

Identifying the Behavioral Intent to Use Social Media through the application of UTAUT in ANR and Turfgrass Extension

Little research exists on the role Extension Agricultural and Natural Resources professionals play in communicating information about new turfgrass cultivars. In an effort to analyze behavioral intentions related to social media and its use in the turfgrass industry, the researchers drew from the unified theory of acceptance and use of technology (UTAUT). A pilot instrument was developed to measure the intent of University researchers and county-based Extension professionals to use social media to disseminate turfgrass information, as well as their use of social media for seeking turfgrass information. This case study examined the role of county-based ANR Extension professionals across six states, analyzing their role as either creators or disseminators of ANR and turfgrass information, their intent to use social media, and their use of these communications to engage with ANR and turfgrass information. Findings of this study show that Facebook is the primary communications channel used by county-based Extension professionals. Further, it has been determined that the role of the county-based Extension professional in “creating” verses “using” previously established research-based information to disseminate to clientele is not well-defined. Broader implications include examination of performance expectations of county-based personnel related to their use of social media for communicating turfgrass information

The Metabolism and Transplacental Transfer of Oseltamivir in the Ex Vivo Human Model

Oseltamivir phosphate is extensively metabolized in the ex vivo human placenta model, and the transplacental passage of the metabolite oseltamivir carboxylate is incomplete. Objective. To evaluate the metabolism and transplacental transfer of oseltamivir (Tamiflu) in the ex vivo human placental model. Study Design. Perfusion studies were performed in six placentas from term, uncomplicated deliveries. Concentrations of oseltamivir phosphate (OP) that were 5-6 fold, 20–30 fold, and 600–800 fold above the therapeutic peak were tested, as neither OP nor its active metabolite, oseltamivir carboxylate (OC), could be detected at near-therapeutic concentrations. The transplacental transfer and accumulation of OC were assessed using the 14C antipyrine reference method. Results. OP was extensively metabolized to OC. In the 4 placentas with the highest concentration of OP, OC had a mean clearance index of 0.13 ± 0.08, suggesting that transplacental passage occurs at a relatively low rate. Measurable fetal accumulation occurred in the two placentas with the highest initial concentrations. Conclusions. Oseltamivir phosphate was extensively metabolized in the ex vivo model. Transplacental transfer of the metabolite was incomplete and accumulation was minimal

Air Propellers in Yaw

Report presents the results of tests conducted at Stanford University of a 3-foot model propeller at four pitch settings and at 0 degree, 10 degrees, 20 degrees, and 30 degrees yaw. In addition to the usual propeller coefficients, cross-wind and vertical forces and yawing, pitching, and rolling moments were determined about axes having their origin at the intersection of the blade axis and the axis of rotation. The tests showed that the maximum efficiency was reduced only slightly for angles of yaw up to 10 degrees but that at 30 degrees yaw the loss in efficiency was about 10 percent. In all cases the cross-wind force was found to be greater than the cross-wind component of the axial thrust. With a yawed propeller an appreciable thrust was found for v/nd for zero thrust at zero yaw. Yawing a propeller was found to induce a pitching moment that increased in magnitude with yaw