Development of the technology for the fabrication of reliable laminar from control panels

Materials were assessed and fabrication techniques were developed for use in the manufacture of wing surface materials compatible with the application of both aluminum alloys and nonmetallic composites. The concepts investigated included perforations and slots in the metallic test panels and microporosity and perforations in the composite test panels. Perforations were produced in the metallic test panels by the electron beam process and slots were developed by controlled gaps between the metal sheets. Microporosity was produced in the composite test panels by the resin bleed process, and perforations were produced by the fugitive fiber technique. Each of these concepts was fabricated into test panels, and air flow tests were conducted on the panels

Study of the application of advanced technologies to laminar-flow control systems for subsonic transports. Volume 2: Analyses

For abstract, see N76-24144

Analysis of HIV-1 reverse transcriptase inhibition by multiple RNA aptamers

Abstract only availableFaculty Mentor: Donald H. Burke, Molecular Microbiology and ImmunologyRapidly increasing resistance to currently available HIV-1 drugs has prompted the exploration of therapies less susceptible to resistance development. Anti-HIV-1 treatments often target reverse transcriptase (RT), the viral protein that polymerizes the integrated DNA copy of the viral RNA genome. For many such drugs, resistance requires only a few amino acid changes in the RT protein. Aptamers are small, single stranded nucleic acids that form unique three-dimensional structures allowing specific binding to molecular targets. When bound to proteins, aptamers often hinder their native function. RNA and DNA aptamers that bind to viral proteins and inhibit HIV-1 at several stages of infection have been isolated. Burke et al, (1996) have proposed that variability in anti-RT aptamer structures may overcome the development of resistance because of different contacts with the RT protein.  Here, multiple anti-HIV-1 RT RNA aptamers (118 or 134 nucleotides in length) were screened for inhibition of RT-catalyzed DNA polymerization. Aptamer inhibition of RT activity was measured using an HIV-derived synthetic template and fluorescently-labeled primers, and by quantifying the amount of fully extended primer. Sixty-two aptamers were screened and grouped according to inhibition performance. In the “BEST” category, twenty-two aptamers displayed ~100 percent inhibition at the highest aptamer concentration (100 nM) and half-maximal inhibition (IC50) values of less than 3 nM. The “VERY GOOD” category contains twenty aptamers with greater than 90 percent inhibition at the highest concentration and IC50 values between 3 nM and 9.5 nM. Of the remaining samples, “MODEST” aptamers yielded 25 to 80 percent inhibition and “POOR” aptamers showed less than 20 percent inhibition at the highest aptamer concentration. Furthermore, sequence and structural analyses may reveal variations in the aptamer-protein interaction between potent aptamers. These data may define the critical interactions between the aptamer and RT, increasing inhibition potency while reducing susceptibility to resistance

Study of the application of advanced technologies to laminar flow control systems for subsonic transports. Volume 1: Summary

A study was conducted to evaluate the technical and economic feasibility of applying laminar flow control to the wings and empennage of long-range subsonic transport aircraft compatible with initial operation in 1985. For a design mission range of 10,186 km (5500 n mi), advanced technology laminar-flow-control (LFC) and turbulent-flow (TF) aircraft were developed for both 200 and 400-passenger payloads, and compared on the basis of production costs, direct operating costs, and fuel efficiency. Parametric analyses were conducted to establish the optimum geometry for LFC and TF aircraft, advanced LFC system concepts and arrangements were evaluated, and configuration variations maximizing the effectiveness of LFC were developed. For the final LFC aircraft, analyses were conducted to define maintenance costs and procedures, manufacturing costs and procedures, and operational considerations peculiar to LFC aircraft. Compared to the corresponding advanced technology TF transports, the 200- and 400-passenger LFC aircraft realized reductions in fuel consumption up to 28.2%, reductions in direct operating costs up to 8.4%, and improvements in fuel efficiency, in ssm/lb of fuel, up to 39.4%. Compared to current commercial transports at the design range, the LFC study aircraft demonstrate improvements in fuel efficiency up to 131%. Research and technology requirements requisite to the development of LFC transport aircraft were identified

Evaluation of advanced lift concepts and fuel conservative short-haul aircraft, volume 2

For abstract, see N75-20291

Evaluation of advanced lift concepts and fuel conservative short-haul aircraft, volume 1

The performance and economics of a twin-engine augmentor wing airplane were evaluated in two phases. Design aspects of the over-the-wing/internally blown flap hybrid, augmentor wing, and mechanical flap aircraft were investigated for 910 m. field length with parametric extension to other field lengths. Fuel savings achievable by application of advanced lift concepts to short-haul aircraft were evaluated and the effect of different field lengths, cruise requirements, and noise levels on fuel consumption and airplane economics at higher fuel prices were determined. Conclusions and recommendations are presented

Influence of Mechanical Layering and Natural Fractures on Undercutting and Rapid Headward Erosion (Recession) at Canyon Lake Spillway, Texas, U.S.A

This study investigates the role of mechanical layering and fractures on flood-related erosional undercutting and resulting rapid spillway recession. In the summer of 2002, 86 cm of rain fell in an 8-day period across the Guadalupe River drainage basin in central Texas, causing Canyon Lake reservoir to completely fill and overtop the emergency spillway for the first time. The resulting flood incised a gorge into the mechanically layered Glen Rose Formation and caused headward erosion (recession) at the downstream edge of the emergency spillway. Comparison of pre- and post-flood imagery and assessment of flood records indicates that maximum recession localized at the northern end of the emergency spillway where 28 m recession occurred. This recession occurred at an estimated rate of up to 10 m/day during the first ~3 days of the flood, which is among the highest rates of recorded bedrock recession. Analysis of historical photographs, field observations and measurement of erosional undercutting, along with measurements of fracture orientation, fracture spacing, and mechanical rebound are used to understand rock mass characteristics that influenced erosional undercutting and rapid recession of the spillway. Evidence of significant undercutting was observed where incompetent argillaceous wackestone (marl) underlies competent limestone. These results reveal that the greatest amount and rate of recession of the spillway was associated with undercutting and toppling collapse of fracture-bounded limestone blocks. Block size may be a factor in continuation of the process, in that large blocks may accumulate at the base of the scarp and inhibit continued erosional undercutting, whereas in other areas smaller eroded blocks can be carried away by the floodwaters and undercutting may continue, facilitating recession. The combination of mechanical contrast between layers and natural fractures in competent layers together contributed to exceptionally high rates of headward erosion. Observed rock mass erodibility behavior was in the range of medium to high erodibility in limestone with widely spaced fractures that would normally be expected to have very low erodibility. Bulk rock mass erodibility in this situation was similar to the most erodibile layer, specifically, the marl at base of spillway pour-off cliff

A comparison of academic achievement and retention of community college students in college algebra after completion of traditional or technology-based instruction

This study was designed to compare the success rates in College Algebra between two groups of students attending a Mississippi community college. Eighty students enrolled in a College Algebra course were taught using traditional instructional techniques, and 70 students received technology-enhanced instruction. This study considered the effects of grade scores on a mathematics-achievement pretest and posttest, student attitudes toward mathematics, time-on-task while using technology during mathematics study, mathematics subscores on the American College Test, and withdrawal rates. Data collected for this study were derived from the official transcripts of students enrolled in spring 2007 College Algebra classes of a Mississippi community college serving as the study site. A total of 150 students participated in the study. Statistical analysis included t tests, chi-square tests, Pearson product-moment correlations, and analysis of covariance to examine relationships between the two groups of students. The results indicate that the students who received College Algebra instruction via technology-based methods learned equally as well as the students who received the same instruction via traditional methods. The findings also indicate that the students who participated in the traditional College Algebra course had improved attitudes toward mathematics upon completion of the semester. With regard to those who participated in the technology-based College Algebra course, the amount of time devoted to technology use during mathematics study did not correlate to their final grades (i.e., grades were not higher as this expenditure of time increased)

An analysis of systems that train and release servant leaders for the edification of the church and the evangelization of the world

https://place.asburyseminary.edu/ecommonsatsdissertations/1228/thumbnail.jp

An Analysis of the Modern Mathematics Program in Grades Four Through Eight of the Cashmere School System

The purpose of this study was to analyze the modern mathematics program of the fourth through eighth grades of the Cashmere School District, Cashmere, Washington