Individual Stylistic Variability in Independence I Stone Tool Assemblages from Port Refuge, N.W.T.

Typological comparisons of stone tool assemblages have traditionally been seen as a means of assessing the relationships between components within the Arctic Small Tool tradition (ASTt). Excavation at Independence I components at Port Refuge, Devon Island, allows us to examine this assumption. These components consist of spatially discrete features, most of which appear to be the remains of single family dwellings occupied only once and for a short period of time. It can probably be assumed that the majority of artifacts associated with any feature were manufactured by the individuals who occupied that feature. Marked differences can be seen between feature assemblages in the proficiency with which stone tools were made, and individual stylistic preferences can be postulated on the bases of intra-feature uniformities. If the hypothesis ascribing a great deal of stylistic variability to individual ability and preference is correct, typological comparisons of Canadian ASTt stone tool assemblages may be of relatively little use in judging the relationships between components

Advanced natural laminar flow airfoil with high lift to drag ratio

An experimental verification of a high performance natural laminar flow (NLF) airfoil for low speed and high Reynolds number applications was completed in the Langley Low Turbulence Pressure Tunnel (LTPT). Theoretical development allowed for the achievement of 0.70 chord laminar flow on both surfaces by the use of accelerated flow as long as tunnel turbulence did not cause upstream movement of transition with increasing chord Reynolds number. With such a rearward pressure recovery, a concave type deceleration was implemented. Two-dimensional theoretical analysis indicated that a minimum profile drag coefficient of 0.0026 was possible with the desired laminar flow at the design condition. With the three-foot chord two-dimensional model constructed for the LTPT experiment, a minimum profile drag coefficient of 0.0027 was measured at c sub l = 0.41 and Re sub c = 10 x 10 to the 6th power. The low drag bucket was shifted over a considerably large c sub l range by the use of the 12.5 percent chord trailing edge flap. A two-dimensional lift to drag ratio (L/D) was 245. Surprisingly high c sub l max values were obtained for an airfoil of this type. A 0.20 chort split flap with 60 deg deflection was also implemented to verify the airfoil's lift capabilities. A maximum lift coefficient of 2.70 was attained at Reynolds numbers of 3 and 6 million

Low-speed wind-tunnel results for symmetrical NASA LS(1)-0013 airfoil

A wind-tunnel test has been conducted in the Langley Low-Turbulence Pressure Tunnel to evaluate the performance of a symmetrical NASA LS(1)-0013 airfoil which is a 13-percent-thick, low-speed airfoil. The airfoil contour was obtained from the thickness distribution of a 13-percent-thick, high-performance airfoil developed for general aviation airplanes. The tests were conducted at Mach numbers from 0.10 tp 0.37 over a Reynolds number range from about 0.6 to 12.0 X 10 to the 6th power. The angle of attack varied from about -8 to 20 degrees. The results indicate that the aerodynamic characteristics of the present airfoil are similar to, but slightly better than, those of the NACA 0012 airfoil

Experimental results for the Eppler 387 airfoil at low Reynolds numbers in the Langley low-turbulence pressure tunnel

Experimental results were obtained for an Eppler 387 airfoil in the Langley Low Turbulence Pressure Tunnel. The tests were conducted over a Mach number range from 0.03 to 0.13 and a chord Reynolds number range for 60,000 to 460,000. Lift and pitching moment data were obtained from airfoil surface pressure measurements and drag data for wake surveys. Oil flow visualization was used to determine laminar separation and turbulent reattachment locations. Comparisons of these results with data on the Eppler 387 airfoil from two other facilities as well as the Eppler airfoil code are included

Reynolds and Mach number effects on multielement airfoils

Experimental studies were conducted to assess Reynolds and Mach number effects on a supercritical multielement airfoil. The airfoil is representative of the stall-critical station of an advanced transport wing design. The experimental work was conducted as part of a cooperative program between the Douglas Aircraft Company and the NASA LaRC to improve current knowledge of high-lift flows and to develop a validation database with practical geometries/conditions for emerging computational methods. This paper describes results obtained for both landing and takeoff multielement airfoils (four and three-element configurations) for a variety of Mach/Reynolds number combinations up to flight conditions. Effects on maximum lift are considered for the landing configurations and effects on both lift and drag are reported for the takeoff geometry. The present test results revealed considerable maximum lift effects on the three-element landing configuration for Reynolds number variations and significant Mach number effects on the four-element airfoil

Aberrant Radiocarbon Dates on an Inuit Arrowhead

Apparently aberrant radiocarbon dates on a Thule culture antler artefact lead to the conclusion that this tool was made of material that was already ancient at the time of manufacture. This finding documents a potential problem in the interpretation of radiocarbon dates on Arctic cultural materials.Des datations au radiocarbone apparemment aberrantes effectuées sur un objet de la culture Thulé fabriqué en bois d'animal permettent de conclure que cet outil a été fait d'un matériau qui était déjà ancien à l'époque de sa fabrication. Ces résultats documentent un problème potentiel dans l'interprétation de la datation au radiocarbone sur des matériaux culturels de l'Arctique

A study of high-lift airfoils at high Reynolds numbers in the Langley low-turbulence pressure tunnel

An experimental study was conducted in the Langley Low Turbulence Pressure Tunnel to determine the effects of Reynolds number and Mach number on the two-dimensional aerodynamic performance of two supercritical type airfoils, one equipped with a conventional flap system and the other with an advanced high lift flap system. The conventional flap system consisted of a leading edge slat and a double slotted, trailing edge flap with a small chord vane and a large chord aft flap. The advanced flap system consisted of a leading edge slat and a double slotted, trailing edge flap with a large chord vane and a small chord aft flap. Both models were tested with all elements nested to form the cruise airfoil and with the leading edge slat and with a single or double slotted, trailing edge flap deflected to form the high lift airfoils. The experimental tests were conducted through a Reynolds number range from 2.8 to 20.9 x 1,000,000 and a Mach number range from 0.10 to 0.35. Lift and pitching moment data were obtained. Summaries of the test results obtained are presented and comparisons are made between the observed aerodynamic performance trends for both models. The results showing the effect of leading edge frost and glaze ice formation is given

Rigid Body Dynamics, Inertial Reference Frames, and Graphics Coordinate Systems: A Resolution of Conflicting Conventions and Terminology

Prepared for: NPS MOVES Academic GroupApproved for public release; distribution is unlimited

Comparison of Elevations of Archaeological Sites and Calculated Sea Levels in Arctic Canada

Based on a study of postglacial uplift in the Canadian Arctic, it has been proposed that relative emergence can be estimated if the age and elevation of late-glacial marine limits are known. This suggestion is used to construct 5 maps showing the amounts of relative sea level emergence since 4000, 3200, 2400, 1600 and 800 BP. The archaeological sequence of coastal arctic Canada has been artificially divided into 5 corresponding 800-year periods. Eighty-four archaeological sites are examined; 71 of these appear to have been located with reference to contemporaneous sea level. The mean elevation of the 71 sites is only 5.2 m above the interpolated sea level for each period; the Spearman rank correlation between site elevations and interpolated sea level is 0.82. The maps can therefore be used to delimit area of search for cultural remains of specific ages in archaeological reconnaissance, but the relationship is not sufficiently close to allow the construction of a detailed chronological sequence using elevation data alone.Comparaison des altitudes de sites archéologiques et de niveaux marins calculés, dans l’Arctique canadien.  Sur la base d’une étude du relèvement post-glaciaire dans l’Arctique canadien, on a proposé que l’émergence relative peut être estimée si l’âge et l’altitude des limites marines fini-glaciaires sont connus.  A partir de cette suggestion, on construit 5 cartes montrant les niveaux d’émergence relative du niveau de la mer depuis 4000, 3200, 2400, 1600 et 800 ans.  Puis, on divise artificiellement la séquence archéologique du Canada arctique côtier en 5 périodes de 800 ans.  Des quatre-vingt-quatre sites archéologiques examinés, 71 semblent localisés par rapport au niveau marin qui leur était contemporain, car l’altitude moyenne de ces 71 sites n’est que 5,2 m au-dessus du niveau moyen interpolé pour chaque période; la corrélation de Spearman entre l’altitude des sites et le niveau marin interpolé est de 0,82.  Ces cartes peuvent ainsi servir à délimiter une aire de recherche de vestiges culturels d’âges spécifiques dans une reconnaissance archéologique d’une séquence chronologique détaillée n’utilisant que les seules données d’altitude

Study of Semi-Span Model Testing Techniques

An investigation has been conducted in the NASA Langley 14- by 22-Foot Subsonic Tunnel in order to further the development of semi-span testing capabilities. A twin engine, energy efficient transport (EET) model with a four-element wing in a takeoff configuration was used for this investigation. Initially a full span configuration was tested and force and moment data, wing and fuselage surface pressure data, and fuselage boundary layer measurements were obtained as a baseline data set. The semi-span configurations were then mounted on the wind tunnel floor, and the effects of fuselage standoff height and shape as well as the effects of the tunnel floor boundary layer height were investigated. The effectiveness of tangential blowing at the standoff/floor juncture as an active boundary-layer control technique was also studied. Results indicate that the semi-span configuration was more sensitive to variations in standoff height than to variations in floor boundary layer height. A standoff height equivalent to 30 percent of the fuselage radius resulted in better correlation with full span data than no standoff or the larger standoff configurations investigated. Undercut standoff leading edges or the use of tangential blowing in the standoff/ floor juncture improved correlation of semi-span data with full span data in the region of maximum lift coefficient