Large-Scale Wind-Tunnel Tests of a Wingless Vertical Take-Off and Landing Aircraft: Preliminary Results

Large-scale wind-tunnel tests were made of a wingless vertical take-off and landing aircraft at zero sideslip to determine performance and longitudinal stability and control characteristics at airspeeds from 0 to 70 knots. Roll control and rudder effectiveness were also obtained. Limitations in the propulsion system restricted the lift for which level flight could be simulated to approximately 1500 pounds. Test variables with roll control and rudder undeflected were airspeed, vane setting, angle of attack, elevator deflection, and power. In most of the tests angle of attack, elevator, and power were varied individually while the other four parameters were held constant at previously determined values required for simulating trimmed level flight. The majority of the tests were made with power on and tail on at airspeeds between 20 and 70 knots. However, a limited number of data were obtained for the following conditions: (1) at zero velocity, horizontal tail on, power on; (2) at forward velocity, tail off and power on; and (3) at forward velocity, tail on, but with power off

Implementing Bluebeam Software in Architectural Engineering Design Courses

A critical aspect of structural engineering education is helping students develop effective electronic graphical communication skills to convey their design solutions. Many undergraduate civil and architectural engineering programs address this at the document creation stage by teaching Autodesk AutoCAD or Revit to create 2-D or 3-D structural design files. However, students tend to have limited exposure to commercial software for document management and markup that allows for coordination between the engineer, architect, and contractor teams. Bluebeam Revu is one such software that has emerged as an industry standard for annotation and markup of engineering design documents. Previous educational studies on the use of Bluebeam have been in construction management courses where students practice plan reading. The main motivation for instructors to incorporate this software in their classes is to expose students to technology they will encounter as practitioners, especially significant since contractors view these drawings as a legal description of their scope of work. Therefore, the production and interpretation of the documents requires that they exhibit a high level of accuracy, specificity, and clarity. This paper focuses on the use of Bluebeam markup and grading in architectural engineering courses to enable communication between faculty and students during the iterative structural design process. The paper provides sample student hand calculations, sketches, and CAD structural drawings with Bluebeam markups provided by practitioner faculty. This markup describes and models how the student might implement necessary design changes. Feedback collected via interviews of course graders, surveys of students, and faculty co-authors is included and illustrates that the use of Bluebeam markup in architectural engineering courses provides a meaningful and efficient review during the development of a structural design solution. The goal of this paper is to show instructors how to integrate Bluebeam into a course, beyond plan reading activities. Faculty will thus be equipped to educate students on a software commonly used in structural design firms for quality assurance/quality control (QA/QC) and communication between the design and construction disciplines

Theoretical design and modeling of an Infantry railgun projectile

In order for railgun technology to be relevant to the Infantry, the design of the projectile must incorporate the following three concepts: an effective ballistics package, geometries for aerodynamic stability; and a non-parasitic conducting armature. I designed an effective 30mm and scaled 40mm projectile which incorporates the aforementioned concepts. My ballistics analysis concluded with two AUTODYN. finite-element computer models that refined theoretical estimates for target penetration. The proposed railgun projectiles were effective in penetrating 100 mm of Rolled Homogenous Armor and in perforating 8 inches of Double Layered Reinforced Concrete. My theoretical analysis in aerodynamics predicts in-flight stability with a minimum static margin of approximately two percent. The analysis and modeling of the electromagnetic launch resulted in an adequate design. For this analysis, I used three Comsol Multiphysics. finite-element computer models. The modeling results validated fundamental railgun equations. The final projectile design concluded with a 3 m barrel and is characterized by the following parameters: conducting rails with an inductance gradient Å OÌ 0.38 Å IÌ H/m; an average temperature rise in the rails of 20 Å CÌ per shot; an effective current of less than 2 MA; and a projectile launch velocity of 1100 m/s.http://archive.org/details/theoreticaldesig109451849Approved for public release; distribution is unlimited

Strategies for selection of subjects for sequencing after detection of a linkage peak

Linkage analysis has the potential to localize disease genes of interest, but the choice of which subjects to select for follow-up sequencing after identifying a linkage peak might influence the ability to find a disease gene. We compare nine different strategies for selection of subjects for follow-up sequencing using sequence data from the Genetic Analysis Workshop 17. We found that our more selective strategies, which included methods to identify case subjects more likely to be affected by genetic causes, out-performed sequencing all case and control subjects in linked pedigrees and required sequencing fewer individuals. We found that using genotype data from population control subjects had a higher benefit-cost ratio than sequencing control subjects selected as being the opposite extreme of the case subjects. We conclude that choosing case subjects for sequencing based on more selective strategies can be reliable and cost-effective

Full-Scale Wind-Tunnel Tests of Blowing Boundary-Layer Control Applied to a Helicopter Rotor

A full-scale wind-tunnel test was conducted of two boundary-layer-control applications to a 44-foot diameter helicopter rotor. Blowing from a nozzle near the leading edge of the blades delayed retreating blade stall. Results also indicated that delay of retreating blade stall could be obtained by cyclic blowing with a lower flow rate than that required for continuous blowing. It was found that blowing applied through a nozzle at mid-chord had no effect on retreating blade stall

Atomic oxygen effects on materials

Understanding of the basic processes of atomic oxygen interaction is currently at a very elementary level. However, measurement of erosion yields, surface morphology, and optical properties for low fluences have brought about much progress in the past decade. Understanding the mechanisms and those factors that are important for proper simulation of low Earth orbit is at a much lower level of understanding. The ability to use laboratory simulations with confidence to quantifiably address the functional performance and durability of materials in low Earth orbit will be necessary to assure long-term survivability to the natural space environment

Environmental Studies on Titanium Aluminide Alloys

Titanium aluminides are attractive alternatives to superalloys in moderate temperature applications (600 to 850 C) by virtue of their high strength-to-density ratio (high specific strength). These alloys are also more ductile than competing intermetallic systems. However, most Ti-based alloys tend to degrade through interstitial embrittlement and rapid oxidation during exposure to elevated temperatures. Therefore, their environmental behavior must be thoroughly investigated before they can be developed further. The goals of titanium aluminide environmental studies at the NASA Lewis Research Center are twofold: characterize the degradation mechanisms for advanced structural alloys and determine what means are available to minimize degradation. The studies to date have covered the alpha 2 (Ti3Al), orthorhombic (Ti2AlNb), and gamma (TiAl) classes of alloys

Impact of age and race on outcomes of a program to prevent excess weight gain and disordered eating in adolescent girls

Interpersonal psychotherapy (IPT) prevents weight gain and reduces loss-of-control (LOC)-eating in adults. However, IPT was not superior to health-education (HE) for preventing excess weight gain and reducing LOC-eating over 1-year in adolescent girls at risk for excess weight gain and eating disorders. Limited data suggest that older and non-White youth may be especially responsive to IPT. In secondary analyses, we examined if age or race moderated weight and LOC-eating outcomes. The 113 participants (12–17 years; 56.6% White) from the original trial were re-contacted 3 years later for assessment. At baseline and follow-up visits through 3 years, we assessed BMI, adiposity by dual energy X-ray absorptiometry, and LOC-eating presence. In linear mixed models, baseline age moderated 3-year BMI outcome; older girls in IPT had the lowest 3-year BMI gain compared to younger girls in IPT and all girls in HE, p = 0.04. A similar pattern was observed for adiposity. Race moderated 3-year LOC-eating; non-White girls in IPT were most likely to abstain from LOC-eating at 3 years compared to all other girls, p = 0.04. This hypothesis-generating analysis suggests future studies should determine if IPT is especially efficacious at reducing LOC-eating in older, non-White adolescents

Price Discovery and the Accuracy of Consolidated Data Feeds in the U.S. Equity Markets

Both the scientific community and the popular press have paid much attention to the speed of the Securities Information Processor, the data feed consolidating all trades and quotes across the US stock market. Rather than the speed of the Securities Information Processor, or SIP, we focus here on its accuracy. Relying on Trade and Quote data, we provide various measures of SIP latency relative to high-speed data feeds between exchanges, known as direct feeds. We use first differences to highlight not only the divergence between the direct feeds and the SIP, but also the fundamental inaccuracy of the SIP. We find that as many as 60 percent or more of trades are reported out of sequence for stocks with high trade volume, therefore skewing simple measures such as returns. While not yet definitive, this analysis supports our preliminary conclusion that the underlying infrastructure of the SIP is currently unable to keep pace with the trading activity in today's stock market.Comment: 18 pages, 20 figures, 2 table

No evidence of BRCA2 mutations in chromosome 13q-linked Utah high-risk prostate cancer pedigrees

<p>Abstract</p> <p>Background</p> <p>Germline mutations in the <it>BRCA2 </it>gene have been suggested to account for about 5% of familial prostate cancer; mutations have been reported in 2% of early onset (i.e., ≤ 55 years) prostate cancer cases and a segregating founder mutation has been identified in Iceland (999del5). However, the role of <it>BRCA2 </it>in high risk prostate cancer pedigrees remains unclear.</p> <p>Findings</p> <p>We examined the potential involvement of <it>BRCA2 </it>in a set offive high-risk prostate cancer pedigrees in which all prostate cases were no more distantly related than two meioses from another case, and the resulting cluster contained at least four prostate cancer cases. We selected these five pedigrees from a larger dataset of 59 high-risk prostate cancer pedigrees analyzed in a genome-wide linkage screen. Selected pedigrees showed at least nominal linkage evidence to the <it>BRCA2 </it>region on chromosome 13q. We mutation screened all coding regions and intron/exon boundaries of the <it>BRCA2 </it>gene in the youngest prostate cancer case who carried the linked 13q segregating haplotype, as well as in a distantly related haplotype carrier to confirm any segregation. We observed no known protein truncating <it>BRCA2 </it>deleterious mutations. We identified one non-segregating <it>BRCA2 </it>variant of uncertain significance, one non-segregating intronic variant not previously reported, and a number of polymorphisms.</p> <p>Conclusion</p> <p>In this set of high-risk prostate cancer pedigrees with at least nominal linkage evidence to <it>BRCA2</it>, we saw no evidence for segregating <it>BRCA2 </it>protein truncating mutations in heritable prostate cancer.</p