2,406 research outputs found
Selected experiments in laminar flow: An annotated bibliography
Since the 1930s, there have been attempts to reduce drag on airplanes by delaying laminar to turbulent boundary layer transition. Experiments conducted during the 1940's, while successful in delaying transition, were discouraging because of the careful surface preparation necessary to meet roughness and waviness requirements. The resulting lull in research lasted nearly 30 years. By the late 1970s, airframe construction techniques had advanced sufficiently that the high surface quality required for natural laminar flow (NLF) and laminar flow control (LFC) appeared possible on production aircraft. As a result, NLF and LFC research became widespread. This report is an overview of that research. The experiments summarized herein were selected for their applicability to small transonic aircraft. Both flight and wind tunnel tests are included. The description of each experiment is followed by corresponding references. Part One summarizes NLF experiments; Part Two deals with LFC and hybrid laminar flow control (HLFC) experiments
Vibration/vacuum screening of space lubricants Final report
Evaluation of solid film lubricants for ball bearings in space environment
Evaluating PrediXcan’s Ability to Predict Differential Expression Between Alcoholics and Non-Alcoholics
PrediXcan is a recent software for the imputation of gene expression from genotype data alone. Using an overlapping set of transcriptome datasets from postmortem brain tissues of donors with alcohol use disorder and neurotypical controls, which were generated by two different platforms (e.g., Arraystar and Affymetrix), and an additional unrelated transcriptome dataset from lung tissue, we sought to evaluate PrediXcan’s ability to impute gene expression and identify differentially expressed genes. From the Arraystar platform, 1.3% of matched genes between the measured and imputed expression had a Pearson correlation ≥ 0.5. Our attempt to replicate this finding using the expression data from the Affymetrix platform also lead to a similarly poor outcome (2.7%). Our third attempt using the transcriptome data from lung tissue produced similar results (1.1%) but performance improved markedly after filtering out genes with a low predicted R2, which was a model metric provided by the PrediXcan authors. For example, filtering out genes with a predicted R2 below 0.6 led to 16 genes remaining and a Pearson correlation of 0.365 between the measured and imputed expression. We were unable to reproduce similar performance gains with filtering the Arraystar or Affymetrix alcohol use disorder datasets. Given that PrediXcan can impute a narrow portion of the transcriptome, which is further reduced significantly by filtering, we believe caution is warranted with the interpretation of results derived from PrediXcan
Personal Experimentation in Drawing
In order to have a true understanding of art there must first be some knowledge of the development as well as of the artist himself. The artist and his work are one but must be looked at from different angles; beginning with the work itself and realizing that the artist creates to satisfy some need or desire which stems from some religious or social beliefs.
When doing comparative resource study, I attemped to combine the drawing skills of extablished artist; such as Walter Campbell, Herbert Railton, Willy Pogany and Aubrey Breadsley in order to improve and express my inner thoughts.
To determine the effects of comparing different styles or techniques of composition, this writer compared different artist and set up standards for line control, perspective and composition of tones.
The illustrations of this writers compositions, included in this paper were originally produced to be examined, analyzed and reflected upon in order for the viewer to understand my thoughts.
By doing a number of drawings with varied subject matters as those previously described and with many variations in techniques I was able to develop certain ideas and transmit these ideas to the viewer through my work. Through experimentation I mastered control in working with pencil and ink while at the same time developed the ability to draw fine lines as well as what line movement to use to obtain a desired effect. I was also able to set up standard of line control, develop perspective and composition of tones and developed the technique of using matting in order to work with rather than against drawings
Personal Experimentation in Drawing
In order to have a true understanding of art there must first be some knowledge of the development as well as of the artist himself. The artist and his work are one but must be looked at from different angles; beginning with the work itself and realizing that the artist creates to satisfy some need or desire which stems from some religious or social beliefs.
When doing comparative resource study, I attemped to combine the drawing skills of extablished artist; such as Walter Campbell, Herbert Railton, Willy Pogany and Aubrey Breadsley in order to improve and express my inner thoughts.
To determine the effects of comparing different styles or techniques of composition, this writer compared different artist and set up standards for line control, perspective and composition of tones.
The illustrations of this writers compositions, included in this paper were originally produced to be examined, analyzed and reflected upon in order for the viewer to understand my thoughts.
By doing a number of drawings with varied subject matters as those previously described and with many variations in techniques I was able to develop certain ideas and transmit these ideas to the viewer through my work. Through experimentation I mastered control in working with pencil and ink while at the same time developed the ability to draw fine lines as well as what line movement to use to obtain a desired effect. I was also able to set up standard of line control, develop perspective and composition of tones and developed the technique of using matting in order to work with rather than against drawings
17-year Report on the Owensboro-Hartford Co-operative Investigation of Joint Spacing in Concrete Pavements
In 1940, the Kentucky Department of Highways constructed an experimental concrete pavement which was one of a group of six built in co-operation with the Bureau of Public Roads by the States of Minnesota, California, Kentucky, Michigan, Missouri and Oregon. The purpose of these projects was to study and evaluate the performance of such pavements over a period of years with specific regard to types of joints and spacings. The Kentucky project, consisting of 6.27 miles, was constructed in Daviess County, beginning approximately 6 miles south of Owensboro on US Route 231 (formerly Ky. Route 71).
This report is a continuation of the 1940 joint-spacing and pavement performance study. A complete discussion of the original scope, purpose, and early performance of this project has been given in previous reports (l, 2, 3, and 4).
The present report is essentially a 17-yr. performance report but includes some data obtained through 1958. Subgrade, traffic, riding quality, and over-all condition data are provided
Sensible heat transfer in the Gemini and Apollo pressure suits
Sensible heat transfer effects in Gemini and Apollo pressure suit
Theoretical energies of low-lying states of light helium-like ions
Rigorous quantum electrodynamical calculation is presented for energy levels
of the 1^1S, 2^1S, 2^3S, 2^1P_1, and 2^3P_{0,1,2} states of helium-like ions
with the nuclear charge Z=3...12. The calculational approach accounts for all
relativistic, quantum electrodynamical, and recoil effects up to orders
m\alpha^6 and m^2/M\alpha^5, thus advancing the previously reported theory of
light helium-like ions by one order in \alpha.Comment: 18 pages, 9 tables, 1 figure, with several misprints correcte
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The influence of the atmospheric boundary layer on nocturnal layers of noctuids and other moths migrating over southern Britain
Insects migrating at high altitude over southern Britain have been continuously monitored by automatically-operating, vertical-looking radars over a period of several years. During some occasions in the summer months, the migrants were observed to form well-defined layer concentrations, typically at heights of 200-400 m, in the stable night-time atmosphere. Under these conditions, insects are likely to have control over their vertical movements and are selecting flight heights which are favourable for long-range migration. We therefore investigated the factors influencing the formation of these insect layers by comparing radar measurements of the vertical distribution of insect density with meteorological profiles generated by the UK Met. Office’s Unified Model (UM). Radar-derived measurements of mass and displacement speed, along with data from Rothamsted Insect Survey light traps provided information on the identity of the migrants. We present here three case studies where noctuid and pyralid moths contributed substantially to the observed layers. The major meteorological factors influencing the layer concentrations appeared to be: (a) the altitude of the warmest air, (b) heights corresponding to temperature preferences or thresholds for sustained migration and (c), on nights when air temperatures are relatively high, wind-speed maxima associated with the nocturnal jet. Back-trajectories indicated that layer duration may have been determined by the distance to the coast. Overall, the unique combination of meteorological data from the UM and insect data from entomological radar described here show considerable promise for systematic studies of high-altitude insect layering
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