35 research outputs found

    Calibration of the 13- by 13-inch adaptive wall test section for the Langley 0.3-meter transonic cryogenic tunnel

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    A 13 by 13 inch adaptive wall test section was installed in the 0.3 Meter Transonic Cryogenic Tunnel circuit. This new test section is configured for 2-D airfoil testing. It has four solid walls. The top and bottom walls are flexible and movable whereas the sidewalls are rigid and fixed. The wall adaptation strategy employed requires the test section wall shapes associated with uniform test section Mach number distributions. Calibration tests with the test section empty were conducted with the top and bottom walls linearly diverged to approach a uniform Mach number distribution. Pressure distributions were measured in the contraction cone, the test section, and the high speed diffuser at Mach numbers from 0.20 to 0.95 and Reynolds numbers from 10 to 100 x 10 (exp 6)/per foot

    Aerodynamic performance and pressure distributions for a NASA SC(2)-0714 airfoil tested in the Langley 0.3-meter transonic cryogenic tunnel

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    This report presents in graphic and tabular forms the aerodynamic coefficient and surface pressure distribution data for a NASA SC(2)-0714 airfoil tested in the Langley 0.3-Meter Transonic Cryogenic Tunnel. The test was another in a series of tests involved in the joint NASA/U.S. Industry Advanced Technology Airfoil Tests program. This 14% thick supercritical airfoil was tested at Mach numbers from 0.6 to 0.76 and angles of attack from -2.0 to 6.0 degrees. The test Reynolds numbers were 4 million, 6 million, 10 million, 15 million, 30 million, 40 million, and 45 million

    High Reynolds Number Test of the Boeing TR77 Airfoil in the Langley 0.3-Meter Transonic Cryogenic Tunnel

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    A Boeing TR77 airfoil associated with the Advanced Technology Airfoil Test (ATAT) program was tested in the Langley 0.3 m Transonic Cryogenic Tunnel. Limited analysis of the data indicated that increasing Reynolds number for a fixed Mach number resulted in increased normal-force, nose-down pitching moment, and decreased drag coefficient. Increasing Mach number while keeping the Reynolds number constant yielded the expected increase in normal-force slopes, nose-down pitching moment coefficients, and decrease in angle of attack associated with maximum normal-force coefficient. Turbulent boundary layer flow was achieved over the airfoil at low Reynolds numbers for the test Mach number range using aluminum discs

    Pressure distributions from high Reynolds number transonic tests of an NACA 0012 airfoil in the Langley 0.3-meter transonic cryogenic tunnel

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    Tests were conducted in the 2-D test section of the Langley 0.3-meter Transonic Cryogenic Tunnel on a NACA 0012 airfoil to obtain aerodynamic data as a part of the Advanced Technology Airfoil Test (ATAT) program. The test program covered a Mach number range of 0.30 to 0.82 and a Reynolds number range of 3.0 to 45.0 x 10 to the 6th power. The stagnation pressure was varied between 1.2 and 6.0 atmospheres and the stagnation temperature was varied between 300 K and 90 K to obtain these test conditions. Tabulated pressure distributions and integrated force and moment coefficients are presented as well as plots of the surface pressure distributions. The data are presented uncorrected for wall interference effects and without analysis

    High Reynolds number tests of a Douglas DLBA 032 airfoil in the Langley 0.3-meter transonic cryogenic tunnel

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    A wind-tunnel investigation of a Douglas advanced-technology airfoil was conducted in the Langley 0.3-Meter Transonic Cryogenic Tunnel (0.3-m TCT). The temperature was varied from 227 K (409 R) to 100 K (180 R) at pressures ranging from about 159 kPa (1.57 atm) to about 514 kPa (5.07 atm). Mach number was varied from 0.50 to 0.78. These variables provided a Reynolds number range (based on airfoil chord) from 6.0 to 30.0 x 10 to the 6th power. This investigation was specifically designed to: (1) test a Douglas airfoil from moderately low to flight-equivalent Reynolds numbers, and (2) evaluate sidewall-boundary-layer effects on transonic airfoil performance characteristics by a systematic variation of Mach number, Reynolds number, and sidewall-boundary-layer removal. Data are included which demonstrate the effects of fixing transition, Mach number, Reynolds number, and sidewall-boundary-layer removal on the aerodynamic characteristics of the airfoil. Also included are remarks on model design and model structural integrity

    High Reynolds number transonic tests on a NACA 0012 airfoil in the Langley 0.3-meter transonic cryogenic tunnel

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    Tests were conducted in the two-dimensional test section of the Langley 0.3-m Transonic Cryogenic Tunnel on a NACA 0012 airfoil to obtain aerodynamic data as a part of the Advanced Technology Airfoil Test (ATAT) program. The test program covered a Mach number range of 0.30 to 0.82 and a Reynolds number range of 3.0 to 45.0 x 10 to the 6th. The stagnation pressure was varied between 1.2 and 6.0 atmospheres and the stagnation temperature was varied between 300 K and 90 K to obtain these test conditions. Plots of the spanwise variation of drag coefficient as a function of normal force coefficient and the variation of the basic aerodynamic characteristics with angle of attack are shown. The data are presented uncorrected for wall interference effects and without analysis

    Problem based learning vs traditional curricula: A comparative study of nursing students' self-directed learning readiness

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    Introduction: Nursing students in a lecture-based learning (LBL) programme, referred to as a traditional curriculum in this study are assumed to be less prepared for self-directed learning (SDL), since little emphasis is placed on (SDL) skill acquisition during their learning process. On the other hand, SDL skills are well described in Problem-Based Learning (PBL), designed to develop students’ self-directedness. In this study context, no baseline data exist about students’ readiness to take responsibility for their learning with respect to their attitude, abilities and/or behaviours necessary for SDL. Purpose: The purpose of this study was to compare the SDL readiness of undergraduate nursing students who are prepared through PBL and LBL curricula in two universities in Johannesburg. Methodology: A descriptive, cross-sectional, comparative design was used to examine and describe the differences between the two groups. Of the total population of 200 nursing students (N=200) 159 responded and comprised the final sample (n=159). A 40-item structured questionnaire, the Self- Directed Learning Readiness Scale (SDLRS) was used to collect data, in the subscales: selfmanagement, desire for learning and self-control. Results: Both groups reported almost equal and acceptable levels (>150) of readiness for SDL, as indicated by similar mean scores in the combined subscales; the difference in their overall readiness was not significant (p=0.69). Students in the PBL group reported higher scores in self-management than the LBL group in the final year Y4; the difference though, was not statistically significant (p=0.82). Students in both groups were similar in their desire for learning at the beginning of the course (Y1), declining sharply in year two (Y2); the PBL group reported a greater desire to learn than the LBL group, in Y4. This difference was not statistically significant (0.90). The PBL group reported a lesser ability for self-control than their LBL counterparts in the junior years, but showed noticeable educational growth in Y4, exceeding that of the LBL group; the LBL group showed no growth at all. Statistically, this difference was not significant (p=0.82). Conclusion: Recommendations were made for the utilization of progressive, less didactic methods in nurse education, based on the SDL readiness levels reported. It was further recommended that future research make use of bigger samples and that practical significance as opposed to statistical significance be used to draw inferences

    Morphometric characteristics and consumer acceptability of meat from Potchefstroom Koekoek, Black Australorp, Venda and Ovambo chickens.

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    Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.Indigenous chicken production receives little institutional support and resources because of lack of information on the socioeconomic importance, morphometric characteristic and meat quality of indigenous chickens. A cross sectional survey was conducted to highlight the major constraints to production. A structured questionnaire was administered to 126 households selected from communities of Mnambiti-Ladysmith and Impendle local municipalities of KwaZulu-Natal Province of South Africa. The mean flock size per household was 20 and 17 for Mnambiti-Ladysmith and Impendle, respectively. The cock to hen ratio was 1:2:5. The chickens were mostly kept for meat and income ranked 1 and 2 respectively. Generally, adult females made the majority of decisions on chicken management and marketing (61%), with youths playing a minor role. Scavenging was the major feeding system, seasonally supplemented with cereal grain. The majority of the farmers (87%) provided birds with drinking water. Mortality of chickens was prevalent (46%) in both seasons. In experiment 2, the objective of the study was to compare morphometric characteristics of Black Australorp, Potchefstroom Koekoek, Venda and Ovambo chickens. A flock of 200 indigenous chickens, 50 each of Black Australorp, Potchefstroom Koekoek, Venda and Ovambo breeds were reared under semi-intensive system for 22 weeks. The chickens were slaughtered at 22 weeks of age by manual neck cut, bled for 2 minutes and de-feathered. Body weights, organ weights and linear body measure were estimated using flexible tape prior to slaughter. The body weight for the Black Australorp were higher (P<0.05) than the other breeds. There was no significant difference between the lung, heart kidney and spleen weights among breeds. Linear regression revealed that measurements of linear body parts can be used to predict weight of the birds. The objective of Experiment 3 was to compare consumer acceptability of meat from chickens that are indigenous to South Africa compared to Black Australorp and the broiler. A flock of 200 unsexed freely ranging indigenous chickens of Potchefstroom Koekoek, Venda, Black Australorp and Ovambo breeds were reared under an improved semi-intensive system for 22 weeks. The acceptability of cooked meat samples from each breed was rated on a 9 point Hedonic scale by 69 consumer pannellists drawn from the University of KwaZulu-Natal, Cedara College of Agriculture and the Depart of Agriculture. Age of consumer had no effect on all the sensory attributes of the meat evaluated (P> 0.05). Chicken breed had a significant effect on taste and overall acceptability (P< 0.05) with the Venda, Broiler and Black Australorp, but it had no significant difference on colour, texture and aroma acceptability. Gender of the consumer had a significant effect (p<0.01) on taste, colour and texture acceptability of the meat, but no significant effect on aroma and overall acceptability. Female respondents gave lower scores for taste than did the males (P< 0.01). There was no interaction between gender of consumer and chicken breed on meat texture. Crossbreeding the indigenous chickens with improved breeds such as the Black Australorp is one avenue through which sensory characteristics of the indigenous chickens may be improved

    Aerodynamic measurements and thermal tests of a strain-gage balance in a cryogenic wind tunnel

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    An internal strain-gage balance designed and constructed in Europe for use in cryogenic wind tunnels has been tested in the Langley 0.3-Meter Transonic Cryogenic Tunnel. Part of the evaluation was made at equilibrium balance temperatures and it consisted of comparing the data taken at a tunnel stagnation temperature of 300 K with the data taken at 200 K and 110 K while maintaining either the Reynolds number or the stagnation pressure. A sharp-leading-edge delta-wing model was used to provide the aerodynamic loading for these tests. Results obtained with the balance during the force tests were found to be accurate and repeatable both with and without the use of a convection shield on the balance. An additional part of this investigation involved obtaining data on the transient temperature response of the balance during both normal and rapid changes in the tunnel stagnation temperature. The variation of the temperature with time was measured at three locations on the balance near the physical locations of the strain gages. The use of a convection shield significantly increased the time required for the balance to stabilize at a new temperature during the temperature response tests
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