5,005 research outputs found
FLEXSTAB: A computer program for the prediction of loads and stability and control of flexible aircraft
Capabilities of the FLEXSTAB Computer Program System are described and illustrated. Aeroelastic analysis of a wide variety of aircraft configurations is performed. The aerodynamic theory used in FLEXSTAB is applicable to both steady and unsteady, subsonic and supersonic flow for multiple wing-body tail nacelle configurations with a plane of symmetry. For unsteady flow calculations, an unsteady aerodynamic theory is used which is appropriate for the low reduced frequencies associated with aircraft flight dynamics. The aircraft is modeled as either a rigid or flexible structure. The computer trims the aircraft in steady reference flight and computes both static and dynamic stability and control derivatives and the stability behavior about the trim condition. The airplane lifting pressure distribution, aerodynamic and inertia loads and deflected shape are also computed
Calculation of static longitudinal aerodynamic characteristics of STOL aircraft with upper surface blown flaps
An existing prediction method developed for EBF aircraft configurations was applied to USB configurations to determine its potential utility in predicting USB aerodynamic characteristics. An existing wing-flap vortex-lattice computer program was modified to handle multiple spanwise flap segments at different flap angles. A potential flow turbofan wake model developed for circular cross-section jets was used to model a rectangular cross-section jet wake by placing a number of circular jets side by side. The calculation procedure was evaluated by comparison of measured and predicted aerodynamic characteristics on a variety of USB configurations. The method is limited to the case where the flow and geometry of the configuration are symmetric about a vertical plane containing the wing root chord. Comparison of predicted and measured lift and pitching moment coefficients were made on swept wings with one and two engines per wing panel, various flap deflection angles, and a range of thrust coefficients. The results indicate satisfactory prediction of lift for flap deflections up to 55 and thrust coefficients less than 2. The applicability of the prediction procedure to USB configurations is evaluated, and specific recommendations for improvements are discussed
Application of winglets and/or wing tip extensions with active load control on the Boeing 747
The application of wing tip modifications and active control technology to the Boeing 747 airplane for the purpose of improving fuel efficiency is considered. Wing tip extensions, wing tip winglets, and the use of the outboard ailerons for active wing load alleviation are described. Modest performance improvements are indicated. A costs versus benefits approach is taken to decide which, if any, of the concepts warrant further development and flight test leading to possible incorporation into production airplanes
An algorithm for diagnosing IgE-mediated food allergy in study participants who do not undergo food challenge.
BACKGROUND: Food allergy diagnosis in clinical studies can be challenging. Oral food challenges (OFC) are time-consuming, carry some risk and may, therefore, not be acceptable to all study participants. OBJECTIVE: To design and evaluate an algorithm for detecting IgE-mediated food allergy in clinical study participants who do not undergo OFC. METHODS: An algorithm for trial participants in the Barrier Enhancement for Eczema Prevention (BEEP) study who were unwilling or unable to attend OFC was developed. BEEP is a pragmatic, multi-centre, randomized-controlled trial of daily emollient for the first year of life for primary prevention of eczema and food allergy in high-risk infants (ISRCTN21528841). We built on the European iFAAM consensus guidance to develop a novel food allergy diagnosis algorithm using available information on previous allergenic food ingestion, food reaction(s) and sensitization status. This was implemented by a panel of food allergy experts blind to treatment allocation and OFC outcome. We then evaluated the algorithm's performance in both BEEP and Enquiring About Tolerance (EAT) study participants who did undergo OFC. RESULTS: In 31/69 (45%) BEEP and 44/55 (80%) EAT study control group participants who had an OFC the panel felt confident enough to categorize children as "probable food allergy" or "probable no food allergy". Algorithm-derived panel decisions showed high sensitivity 94% (95%CI 68, 100) BEEP; 90% (95%CI 72, 97) EAT and moderate specificity 67% (95%CI 39, 87) BEEP; 67% (95%CI 39, 87) EAT. Sensitivity and specificity were similar when all BEEP and EAT participants with OFC outcome were included. CONCLUSION: We describe a new algorithm with high sensitivity for IgE-mediated food allergy in clinical study participants who do not undergo OFC. CLINICAL RELEVANCE: This may be a useful tool for excluding food allergy in future clinical studies where OFC is not conducted
Artificial light and nocturnal activity in gammarids
Artificial light is gaining attention as a potential stressor to aquatic
ecosystems. Artificial lights located near streams increase light levels
experienced by stream invertebrates and we hypothesized light would depress
night drift rates. We also hypothesized that the effect of light on drift
rates would decrease over time as the invertebrates acclimated to the new
light level over the course of one month’s exposure. These hypotheses were
tested by placing Gammarus spp. in eight, 75 m × 1 m artificial flumes. One
flume was exposed to strong (416 lx) artificial light at night. This strong
light created a gradient between 4.19 and 0.04 lx over the neighboring six
artificial flumes, while a control flume was completely covered with black
plastic at night. Night-time light measurements taken in the Berlin area
confirm that half the flumes were at light levels experienced by urban aquatic
invertebrates. Surprisingly, no light treatment affected gammarid drift rates.
In contrast, physical activity measurements of in situ individually caged G.
roeseli showed they increased short-term activity levels in nights of complete
darkness and decreased activity levels in brightly lit flumes. Both nocturnal
and diurnal drift increased, and day drift rates were unexpectadly higher than
nocturnal drift
Professionalism as a Generalized Typical Model of a Professional in the Higher Education System
The purpose of the article is to consider the impact of professionalism and professional activities on creating a generalized model of the professional. The thesis stating that professionalism is a generalized typical model (image) of the professional, prevailing in mentality of a particular society and including normative and actual models, was substantiated. Generalized typical model of the professional in the higher education system was considered in terms of normative and actual professionalism. Normative model serves a benchmark in organizing professional activities and includes the requirements of the profession, education and human being
Shifting the evaluative gaze: Community-based program evaluation in the homeless sector
Homelessness is a growing social issue that is a consequence of structural inequities and contributor to the development of health inequities. Community-based research (CBR) has been proposed as an effective research strategy for addressing health equities and promoting social justice through participatory processes. The purpose of this article is to examine the application of CBR principles and practices in the homeless sector and the implications for the production of knowledge and social change to address homelessness. Drawing on our experiences as researchers and service providers, we reflect on the significant successes and challenges associated with using CBR in the homelessness sector. In our discussion we emphasise insights, challenges and lessons learned from a community-university partnership that focused on an evaluation of a transitional shelter program in a large urban centre where housing is expensive and often unavailable.Keywords: Homelessness, housing, transitional housing, transitional shelter, program evaluation, community-based researc
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