Measurement and analysis of a small nozzle plume in vacuum

Pitot pressures and flow angles are measured in the plume of a nozzle flowing nitrogen and exhausting to a vacuum. Total pressures are measured with Pitot tubes sized for specific regions of the plume and flow angles measured with a conical probe. The measurement area for total pressure extends 480 mm (16 exit diameters) downstream of the nozzle exit plane and radially to 60 mm (1.9 exit diameters) off the plume axis. The measurement area for flow angle extends to 160 mm (5 exit diameters) downstream and radially to 60 mm. The measurements are compared to results from a numerical simulation of the flow that is based on kinetic theory and uses the direct-simulation Monte Carlo (DSMC) method. Comparisons of computed results from the DSMC method with measurements of flow angle display good agreement in the far-field of the plume and improve with increasing distance from the exit plane. Pitot pressures computed from the DSMC method are in reasonably good agreement with experimental results over the entire measurement area

Performance results of the high-gain Nd:glass engineering prototype preamplifier module (PAM) for the National Ignition Facility (NIF)

We describe recent, energetics performance results on the engineering preamplifier module (PAM) prototype located in the front end of the 1.8MJ National Ignition Facility (NIF) laser system. Three vertically mounted subsystem located in the PAM provide laser gain as well as spatial beam shaping. The first subsystem in the PAM prototype is a diode pumped, Nd:glass, linear, TEM{sub 00}, 4.5m long regenerative amplifier cavity. With a single diode pumped head, we amplify a 1nJ, mode matched, temporally shaped ({approx} 20ns) seed pulse by a factor of approximately 10{sup 7} to 20mJ. The second subsystem in the PAM is the beam shaping module, which magnifies the gaussian output beam of the regenerative amplifier to provide a 30mm x 30mm square beam that is spatially shaped in two dimensions to pre-compensate for radial gain profiles in the main amplifiers. The final subsystem in the PAM is the 4-pass amplifier which relay images the 1mJ output of the beam shaper through four gain passes in a {phi}5cm x 48cm flashlamp pumped rod amplifier, amplifying the energy to 175. The system gain of the PAM is 10{sup 10}. Each PAM provides 35 of injected energy to four separate main amplifier chains which in turn delivers 1.8MJ in 192 frequency converted laser beams to the target for a broad range of laser fusion experiments

Integrated operations of the National Ignition Facility (NIF) optical pulse generation development system

We describe the Optical Pulse Generation (OPG) testbed, which is the integration of the MOR and Preamplifier Development Laboratories. We use this OPG testbed to develop and demonstrate the overall capabilites of the NIF laser system front end. We will present the measured energy and power output, temporal and spatial pulse shaping capability, FM bandwidth and dispersion for beam smoothing, and measurements of the pulse-to-pulse power variation of the OPG system and compare these results with the required system performance specifications. We will discuss the models that are used to predict the system performance and how the OPG output requirements flowdown to the subordinate subsystems within the OPG system

Desmoglein-2 is Important for Islet Function and β-Cell Survival

Type 1 diabetes is a complex disease characterized by the lack of endogenous insulin secreted from the pancreatic β-cells. Although β-cell targeted autoimmune processes and β-cell dysfunction are known to occur in type 1 diabetes, a complete understanding of the cell-to-cell interactions that support pancreatic function is still lacking. To characterize the pancreatic endocrine compartment, we studied pancreata from healthy adult donors and investigated a single cell surface adhesion molecule, desmoglein-2 (DSG2). Genetically-modified mice lacking Dsg2 were examined for islet cell mass, insulin production, responses to glucose, susceptibility to a streptozotocin-induced mouse model of hyperglycaemia, and ability to cure diabetes in a syngeneic transplantation model. Herein, we have identified DSG2 as a previously unrecognized adhesion molecule that supports β-cells. Furthermore, we reveal that DSG2 is within the top 10 percent of all genes expressed by human pancreatic islets and is expressed by the insulin-producing β-cells but not the somatostatin-producing δ-cells. In a Dsg2 loss-of-function mice (Dsg

BRAFV600E mutation is highly prevalent in thyroid carcinomas in the young population in Fukushima: a different oncogenic profile from Chernobyl

After the accident at the Fukushima Daiichi Nuclear Power Plant, the thyroid ultrasound screening program for children aged 0-18 at the time of the accident was started from October 2011. The prevalence of thyroid carcinomas in that population has appeared to be very high (84 cases per 296,253). To clarify the pathogenesis, we investigated the presence of driver mutations in these tumours. 61 classic papillary thyroid carcinomas (PTCs), two follicular variant PTCs, four cribriform-morular variant PTCs and one poorly-differentiated thyroid carcinoma were analysed. We detected BRAF V600E in 43 cases (63.2%), RET/PTC1 in six (8.8%), RET/PTC3 in one (1.5%) and ETV6/NTRK3 in four (5.9%). Among classic and follicular variant PTCs, BRAF V600E was significantly associated with the smaller size. The genetic pattern was completely different from post-Chernobyl PTCs, suggesting non-radiogenic etiology of these cancers. This is the first study demonstrating the oncogene profile in the thyroid cancers discovered by large mass screening, which probably reflects genetic status of all sporadic and latent tumours in the young Japanese population. It is assumed that BRAF V600E may not confer growth advantage on paediatric PTCs, and many of these cases grow slowly, suggesting that additional factors may be important for tumour progression in paediatric PTCs

Application of a reynolds-stress turbulence model to gas turbine combustor calculations

© 1999 by the American Institute of Aeronautics and Astronautics, Inc. A Reynolds-stress turbulence model and a 16-species, 23-step kinetic mechanism for hydrocarbon combustion are applied in a CFD code to analyze two combustor configurations: 1) A lean, pre-mixed, gaseous propane-air laboratory burner, and 2) A simple liquid-spray combustor burning Jet-A fuel. Computed flow fields for the propane-air system are compared with the Reynolds-stress model and a conventional k-ε. model. Computed NO production with each turbulence model is compared to experimental data for this case. Computed results are presented for the liquid-spray combustor to demonstrate the utility of applying a higher-order turbulence model and a moderately complex kinetic mechanism to the problem of combustor analysis

Design and determination of radial air swirler blade lengths using CFD

The effect of blade length on the swirl strength inside a combustor with a radial air swirler is analyzed using computational fluid dynamics (CFD). The objective is to determine the blade length that produces a flow field with the strongest swirl and recirculation for a given swirler blade angle. The air swirler analyzed in this study has fifteen blades, each inclined at 60° from the radius. The swirler is attached atop a cylindrical combustor. Swirl numbers for various blade lengths are calculated, and the size of the recirculation zones are compared. Both the size of the recirculation zone and swirl number have maximum values at L/W=l.8, where L is blade length and W blade spacing

Effects of Passively Induced Hyperthermia on a Single Bout of Anaerobic Exercise

PURPOSE: The purpose of this pilot study was to establish a protocol to assess the effects of passively induced hyperthermia on the ability to produce and maintain a 30s-anaerobic bout of exercise. It was hypothesized that both Peak Power Output (PPO) and Mean Power Output (MPO) would decrease in hyperthermia when compared to normothermia. METHODS: The Simon Fraser University Office of Research Ethics approved the study. Prior to participating in the study, each volunteer was given a laboratory orientation, a 24 h reflection period, completed PAR-Q and medical history forms, and gave a signed, informed consent. Two healthy male volunteers aged 40 ±22.6 years (mean±SD) with a Body Mass Index of 24.0 ± 0.05 kg/m2 participated in the study. Esophageal Temperature (TES) was measured with a thermocouple probe inserted to the level of the left ventricle. Peak Power Output (PPO) and Mean Power Output (MPO) were measured on a Lode electrically-braked cycle ergometer. Each participant performed a 30s Wingate Anaerobic Test (WAnT) in one of two thermal states, normothermic or hyperthermic. Each volunteer was rendered hyperthermic in a warm bath. RESULTS: A paired two-tailed t-test was employed for differences in TES, PPO, and MPO between thermal states. The significance level was set at 0.05. TES was significantly higher (p\u3c 0.05) at 38.15±0.06oC at the start of exercise in hyperthermia compared to normothermia 37.09±0.05oC. CONCLUSION: No significant changes in PPO was higher at 1074±182.4 Watts (W\u27s) during normothermia compared to hyperthermia at 1013.5±205.8 W’s, the difference was not significant (p=0.17). MPO was higher at 583.5±106.8 W\u27s during normothermia compared to hyperthermia at 570.5±135.1 W’s, however the difference was not significant (p=0.63). In conclusion, these preliminary results suggest passively reaching a hyperthermic core temperature has no effect on either PPO or MPO during a maximal anaerobic bout of exercise. Supported by NSERC and CF