Laser transit anemometer measurements on a slender cone in the Langley unitary plan wind tunnel

A laser transit anemometer (LTA) system was used to probe the boundary layer on a slender (5 degree half angle) cone model in the Langley unitary plan wind tunnel. The anemometer system utilized a pair of laser beams with a diameter of 40 micrometers spaced 1230 micrometers apart to measure the transit times of ensembles of seeding particles using a cross-correlation technique. From these measurements, boundary layer profiles around the model were constructed and compared with CFD calculations. The measured boundary layer profiles representing the boundary layer velocity normalized to the edge velocity as a function of height above the model surface were collected with the model at zero angle of attack for four different flow conditions, and were collected in a vertical plane that bisected the model's longitudinal center line at a location 635 mm from the tip of the forebody cone. The results indicate an excellent ability of the LTA system to make velocity measurements deep into the boundary layer. However, because of disturbances in the flow field caused by onboard seeding, premature transition occurred implying that upstream seeding is mandatory if model flow field integrity is to be maintained. A description and results of the flow field surveys are presented

Re-entrant ferroelectricity in liquid crystals

The ferroelectric (Sm C$^*$) -- antiferroelectric (Sm C$^*_A$) -- reentrant ferroelectric (re Sm C$^*$) phase temperature sequence was observed for system with competing synclinic - anticlinic interactions. The basic properties of this system are as follows (1) the Sm C$^*$ phase is metastable in temperature range of the Sm C$^*_A$ stability (2) the double inversions of the helix handedness at Sm C$^*$ -- Sm C$^*_A$ and Sm C$^*_A$% -- re-Sm C$^*$ phase transitions were found (3) the threshold electric field that is necessary to induce synclinic ordering in the Sm C$^*_A$ phase decreases near both Sm C$^*_A$ -- Sm C$^*$ and Sm C$^*_A$ -- re-Sm C$^*$ phase boundaries, and it has maximum in the middle of the Sm C$^*_A$ stability region. All these properties are properly described by simple Landau model that accounts for nearest neighboring layer steric interactions and quadrupolar ordering only.Comment: 10 pages, 5 figures, submitted to PR

Talking about weight talk : primary care practitioner knowledge, attitudes and practice

Background: Primary care practitioners (PCPs) have a vital role in patient weight management. This study investigates knowledge, attitudes and practice of UK PCPs regarding patient weight management. Methods: A cross-sectional questionnaire assessed PCP perceived knowledge, self-reported practice, attitudes towards overweight/obesity and actual knowledge regarding overweight and obesity management. Practitioners from NE Scotland were invited to participate. Results: Participants comprised 107 PCPs. Most participants viewed management of overweight and obesity as core to their roles and 75% reported discussing weight with overweight/obese patients. Management techniques included discussion and advice provision. Behavioural change techniques (BCTs) were reported infrequently, despite perceptions that patients lacked motivation to lose weight. A quarter of participants reported a lack of training and a third reported inadequate skills to manage overweight/obese patients. Mean percent correct for knowledge questions was approximately 53%. Barriers to patient weight management included lack of specialists for referral and limited time. Conclusions: This study confirmed a primary care role in managing weight in overweight/obese patients. Our finding that most participants reported discussing weight with their overweight or obese patients is unsupported by previously published research, however, a more comprehensive sample of practitioners is required to scrutinize this disparity. Incongruence exists between practitioners’ perceptions of difficulties associated with patient weight loss and the tools they use to address them. Inclusion of training in BCT, the provision of weight care specialists, or referral on to commercial weight loss organizations may provide more effective pathways for PCPs to assist weight loss for overweight/obese patients in primary care.PostprintPeer reviewe

Solid State Neutral Particle Analyzer Array on NSTX

A Solid State Neutral Particle Analyzer (SSNPA) array has been installed on the National Spherical Torus Experiment (NSTX). The array consists of four chords viewing through a common vacuum flange. The tangency radii of the viewing chords are 60, 90, 100, and 120 cm. They view across the three co-injection neutral beam lines (deuterium, 80 keV (typ.) with tangency radii 48.7, 59.2, and 69.4 cm) on NSTX and detect co-going energetic ions. A silicon photodiode used was calibrated by using a mono-energetic deuteron beam source. Deuterons with energy above 40 keV can be detected with the present setup. The degradation of the performance was also investigated. Lead shots and epoxy are used for neutron shielding to reduce handling any hazardous heavy metal. This method also enables us to make an arbitrary shape to be fit into the complex flight tube

Succinic acid. Heat capacities and thermodynamic properties from 5 to 328 K. An efficient drying procedure

Heat capacities of succinic acid from 5 to 328 K were determined by adiabatic calorimetry. At 298.15 K, values of Cp, So, (Ho-H0o)/T and (Go-H0o)/T are 36.55, 39.99, 20.23, and -19.76 cal K-1 mol-1. No thermal anomalies were detected except that from a trace of occluded water at 272 K, found to be (0.0030 +/- 0.0005) per cent by analysis of the excess enthalpy absorption. Equilibration of pressed pellets for two days in a desiccator over Drierite proved to be an effective final drying technique.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32850/1/0000226.pd

Heat capacities and thermodynamic properties of ammonium and potassium thiocyanates from 5 to 340 K

The heat capacities of ammonium and potassium thiocyanates were determined by adiabatic calorimetry over the range 5 to 340 K, and associated thermodynamic functions were computed from the results. At 298.15 K, the heat capacities Cp/cal K-1 mol-1 and entropies So/cal K-1 mol-1 are 29.98 and 33.52 for NH4SCN and 21.16 and 29.70 for KSCN. In both salts, the heat capacity contribution from libration of the thiocyanate ions may be represented by two Einstein functions up to 250 K. The torsional motion of the ammonium ion increases rapidly above 100 K and contributes more than 6 cal K-1 to the heat capacity above 250 K. Adjuvant data on potassium thiocyanate solutions lead to So = (34.23+/-0.3) cal K-1 mol-1 for SCN-(aq) at 298.15 K.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32848/1/0000224.pd

The Soft X-ray Spectrum from NGC 1068 Observed with LETGS on Chandra

Using the combined spectral and spatial resolving power of the Low Energy Transmission Grating (LETGS) on board Chandra, we obtain separate spectra from the bright central source of NGC 1068 (Primary region), and from a fainter bright spot 4" to the NE (Secondary region). Both spectra are dominated by line emission from H- and He-like ions of C through S, and from Fe L-shell ions, but also include narrow radiative recombination continua, indicating that most of the soft X-ray emission arises in low-temperature (kT few eV) photoionized plasma. We confirm the conclusions of Kinkhabwala et al. (2002), based on XMM-Newton RGS observations, that the entire nuclear spectrum can be explained by recombination/radiative cascade following photoionization, and radiative decay following photoexcitation, with no evidence for hot, collisionally ionized plasma. In addition, this model also provides an excellent fit to the spectrum of the Secondary region, albeit with radial column densities a factor of three lower, as would be expected given its distance from the source of the ionizing continuum. The remarkable overlap and kinematical agreement of the optical and X-ray line emission, coupled with the need for a distribution of ionization parameter to explain the X-ray spectra, collectively imply the presence of a distribution of densities (over a few orders of magnitude) at each radius in the ionization cone. Relative abundances of all elements are consistent with Solar abundance, except for N, which is 2-3 times Solar. The long wavelength spectrum beyond 30 A is rich of L-shell transitions of Mg, Si, S, and Ar, and M-shell transitions of Fe. The velocity dispersion decreases with increasing ionization parameter, as deduced from these long wavelength lines and the Fe-L shell lines.Comment: 12 pages, 11 figures, accepted for publication in Astronomy and Astrophysic

Are the Narrow Line Regions in Active Galaxies Dusty and Radiation Pressure Dominated?

The remarkable similarity between emission spectra of narrow line regions (NLR) in Seyfert Galaxies has long presented a mystery. In photoionization models, this similarity implies that the ionization parameter is nearly always the same, about U ~ 0.01. Here we present dusty, radiation-pressure dominated photoionization models that can provide natural physical insight into this problem. In these models, dust and the radiation pressure acting on it provide the controlling factor in moderating the density, excitation and surface brightness of photoionized NLR structures. Additionally, photoelectric heating by the dust is important in determining the temperature structure of the models. These models can also explain the coexistence of the low-, intermediate- and coronal ionization zones within a single self-consistent physical structure. The radiation pressure acting on dust may also be capable of driving the fast (~3000 km/s) outflows such as are seen in the HST observations of NGC 1068.Comment: 23 pages, 8 figures, Accepted by Ap