Icing and De-Icing of a Propeller with Internal Electric Blade Heaters

An investigation has been made in the NACA Cleveland icing research tunnel to determine the de-icing effectiveness of an experimental configuration of an Internal electric propeller-blade heater. Two atmospheric Icing conditions and two propeller operating conditions were Investigated, In experiments with unheated blades and with heat applied to the blades both continuously and cyclically. Data are presented to show the effect of propeller speed., ambient air temperature and liquid-water concentration, and the duration of the heat-on and cycle times on the power requirements and de-Icing performance of the blade heaters. The extent of ice-covered area on the blades for various icing ax4 operating conditions has been determined. The largest iced area was obtained at the higher ambient-air temperatures and at low propeller speed. The ohord.wise extent of Icing In practically every case was greater than that covered by blade heaters. Adequate de-icing in the heated area with continuous application of heat was obtained with the power available but a maximum power, input of 1250 watts per blade was insufficient for cyclic de-Icing for the range of conditions investigated. Blade-surface temperature rates of rise of 0.2 to 0.7 F per second were obtained and the minimum cooling period for cyclic de-icing was found to be approximately 2-1/2 times the heating period

Model selection via Bayesian information capacity designs for generalised linear models

The first investigation is made of designs for screening experiments where the response variable is approximated by a generalised linear model. A Bayesian information capacity criterion is defined for the selection of designs that are robust to the form of the linear predictor. For binomial data and logistic regression, the effectiveness of these designs for screening is assessed through simulation studies using all-subsets regression and model selection via maximum penalised likelihood and a generalised information criterion. For Poisson data and log-linear regression, similar assessments are made using maximum likelihood and the Akaike information criterion for minimally-supported designs that are constructed analytically. The results show that effective screening, that is, high power with moderate type I error rate and false discovery rate, can be achieved through suitable choices for the number of design support points and experiment size. Logistic regression is shown to present a more challenging problem than log-linear regression. Some areas for future work are also indicated

INCREASED EGG CONSERVATION-IS IT ESSENTIAL FOR RECOVERY OF WHOOPING CRANES IN THE ARANSASIWOOD BUFFALO POPULATION?

The whooping crane (Grus americana) is in a race for survival against adversities (genetic, demographic, and environmental) that are only partially understood. There is increasing evidence of genetic problems (drift, inbreeding, and loss of heterozygosity) in the captive population that likely also exist in the wild Aransas-Wood Buffalo Population (A WP), a consequence of the 1940s population bottleneck. Small populations are vulnerable to extinction through catastrophic events and random changes in productivity or survival. Negative environmental effects faced by whooping cranes include upstream diversion which diminish freshwater (nutrient) inflow into Texas wintering habitats, and expanding human activities along the coast of the Gulf of Mexico. Population and genetic specialists tell us that security against genetic problems, demographic fluctuations, and environmental changes, lies in maximizing population size. An appropriate minimum population goal to overcome the aforementioned problems is 1,000 individuals (Shaffer 1981, Salwasser et al. 1984, Mirande et al. 1993). The Canadian- United States Whooping Crane Recovery Team has accepted 1,000 birds as their goal for the A WP. If habitat is not limiting and inbreeding does not depress viability (rather large uncertainties), another 30+ years must pass before the A WP reaches 1,000 individuals (Mirande et al. 1993). Can the A WP survive 30+ years to reach a minimum secure population level? It seems evident that managers should be cautious and consider what might be done to accelerate A WP growth. Two potential techniques come to mind. One would be to supplement the population with introductions of captive-reared cranes. In previous brief discussions by the recovery teams, this approach has been discounted because of potential disease transmission to the only wild self-sustaining population. The second technique would be to initiate intensive egg management (Fig. 1) as described by Ellis and Gee (2001)

Planar micromachined glass cantilevers utilising integrated Bragg Fabry-Perot cavities

Here we demonstrate a glass cantilever based on a unique micromachining and etching approach, combined with UV written Bragg gratings. We shall also discuss the increase in sensitivity by using two Bragg gratings to form Fabry-Pérot cavity. Cantilevers are in ultra sensitive force sensors used in applications such as Atomic Force Microscopy, mass sensing and acoustic transducers

Implications of Thermal Events on Thrust Emplacement Sequence in the Appalachian Fold and Thrust Belt: Some New Vitrinite Reflectance Data

Interpretation of existing geothermometry data combined with new vitrinite reflectance data, within the framework of a detailed composite tectonic setting, elucidates the evolution of structural sequencing of thrust sheets during the Alleghanian event in the Valley and Ridge Province in Virginia. That the Pulaski thrust sheet preceded the Saltville thrust sheet in the emplacement sequence, and that both reached thermal maxima prior to, or during, respective emplacement may be inferred from vitrinite and other geothermometry data. In contrast, the Narrows and St. Clair thrust sheets probably each attained their thermal maximum after emplacement. New vitrinite reflectance data are consistent with CAI and other temperature-sensitive information heretofore ascertained in the Valley and Ridge Province and support previously established maximum temperatures of ca. 200°C for strata of the Saltville thrust sheet as young as Mississippian. Rmax values from Mississippian coals in the Price Formation of the Saltville sheet, beneath but near the Pulaski thrust, range from 1.61% to 2.60%. At the structural front of the fold and thrust belt, a single Mississippian coal sample from the Bluefield Formation yields an Rmax value of 1.35%. Those coals showing highest Rmax values are more intensely fractured with secondary minerals filling the fractures. Warm fluids introduced during tectonic events may have played at least as important a role as that of combined stratigraphic and tectonic burial

Development and validation of the guideline for reporting evidence-based practice educational interventions and teaching (GREET)

Abstract Background The majority of reporting guidelines assist researchers to report consistent information concerning study design, however, they contain limited information for describing study interventions. Using a three-stage development process, the Guideline for Reporting Evidence-based practice Educational interventions and Teaching (GREET) checklist and accompanying explanatory paper were developed to provide guidance for the reporting of educational interventions for evidence-based practice (EBP). The aim of this study was to complete the final development for the GREET checklist, incorporating psychometric testing to determine inter-rater reliability and criterion validity. Methods The final development for the GREET checklist incorporated the results of a prior systematic review and Delphi survey. Thirty-nine items, including all items from the prior systematic review, were proposed for inclusion in the GREET checklist. These 39 items were considered over a series of consensus discussions to determine the inclusion of items in the GREET checklist. The GREET checklist and explanatory paper were then developed and underwent psychometric testing with tertiary health professional students who evaluated the completeness of the reporting in a published study using the GREET checklist. For each GREET checklist item, consistency (%) of agreement both between participants and the consensus criterion reference measure were calculated. Criterion validity and inter-rater reliability were analysed using intra-class correlation coefficients (ICC). Results Three consensus discussions were undertaken, with 14 items identified for inclusion in the GREET checklist. Following further expert review by the Delphi panelists, three items were added and minor wording changes were completed, resulting in 17 checklist items. Psychometric testing for the updated GREET checklist was completed by 31 participants (n = 11 undergraduate, n = 20 postgraduate). The consistency of agreement between the participant ratings for completeness of reporting with the consensus criterion ratings ranged from 19 % for item 4 Steps of EBP, to 94 % for item 16 Planned delivery. The overall consistency of agreement, for criterion validity (ICC 0.73) and inter-rater reliability (ICC 0.96), was good to almost perfect. Conclusion The final GREET checklist comprises 17 items which are recommended for reporting EBP educational interventions. Further validation of the GREET checklist with experts in EBP research and education is recommended