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  • Other Sources  (25)
  • Aerodynamics  (21)
  • Temperatur  (4)
  • Cell & Developmental Biology
  • General Chemistry
  • Limnology
  • 1945-1949  (25)
  • 1920-1924
  • 1949  (25)
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  • 1945-1949  (25)
  • 1920-1924
Year
  • 1
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    In:  Zeitschrift für Pflanzenernährung, Düngung, Bodenkunde 46:176-190
    Publication Date: 1949
    Description: Zusammenhang zwischen Witterungsverlauf, Wasserbedarf und Erträgen, Aufstellung einer Konstitutionstheorie KATASTER-BESCHREIBUNG: Anpassung an den Wassermangel in der Jugend, Erziehung zur Dürreresistenz KATASTER-DETAIL: Wasserversorgung in der Jugend +, dann Wasserbedarf im Alter +;
    Keywords: Brandenburg ; 1946-48 ; Getreide ; Korrelationsmethode ; Temperatur ; Witterung
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  • 2
    Publication Date: 1949
    Description: Der Autor untersuchte im Freiland die Zeiten zu denen Ausschlüpfen, Begattung und Eiablage des Springwurmwicklers stattfindet. Zudem wurden Temperatur und relative Luftfeuchte gemessen und mit den Beobachtungen zum Schaderreger in Verbindung gesetzt. KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Keywords: Breisgau, Freiburg ; 1943-1944 ; Luftfeuchte ; Pflanzenschädling ; Temperatur ; Wein
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  • 3
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    In:  Nachr. Bl. Biolog. Ztr.-Anst. Braunschweig, p.19
    Publication Date: 1949
    Description: Verbale Beschreibung des Massenauftretens 1948 sowie früheren Massenauftretens (1891, 1922, 1925, 1938 und 1939) KATASTER-BESCHREIBUNG: Zusammenhang zwischen Witterung (Temperatur und Luftfeuchte) und dem Massenauftreten des Käfers KATASTER-DETAIL: Delta T + (Sommer und Winter) und Delta Relf (Sommer) -, dann Massenauftreten im Folgejahr
    Keywords: Deutschland ; 1947-1948 ; Zuckerrüben ; Pflanzenschädling ; Temperatur ; Trockenheit ; Witterung ; Gemüse
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  • 4
    Publication Date: 1949
    Description: Bericht über die Untersuchungen der mikroklimatischen Temperatur- und Feuchtigkeitsbedingungen in Ackerbohnenbeständen sowie über die Beobachtungen des biogenen Vorganges KATASTER-BESCHREIBUNG: Zusammenhang zwischen der Witterung (Temperatur und Luftfeuchte) und der Stärke des Sporenaustritts KATASTER-DETAIL: Delta T und Delta Relf: 8°C 〈 T 〈 22°c und t (Relf 〉 90%) 〉 8h, dann Sporenaustritt ++; t (Benetzung mit tropfbar flüssigem Wasser) +, dann Sporenaustritt +
    Keywords: Sachsen-Anhalt ; 1948 ; Luftfeuchte ; Pflanzenkrankheit ; Temperatur ; Witterung ; Benetzung ; Gemüse
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  • 5
    Publication Date: 2019-06-28
    Description: No abstract available
    Keywords: Aerodynamics
    Type: NACA-RM-L9C04
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  • 6
    Publication Date: 2019-06-28
    Description: The aerodynamic forces on an oscillating airfoil or airfoil-aileron combination of three independent degrees of freedom have been determined. The problem resolves itself into the solution of certain definite integrals, which have been identified as Bessel functions of the first and second kind and of zero and first order. The theory, being based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing-section theory relating to the steady case. The air forces being known, the mechanism of aerodynamic instability has been analyzed in detail. An exact solution, involving potential flow and the adoption of the Kutta condition, has been analyzed in detail. An exact solution, involving potential flow and the adoption of the Kutta condition, has been arrived at. The solution is of a simple form and is expressed by means of an auxiliary parameter K.
    Keywords: Aerodynamics
    Type: NACA-TR-496
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  • 7
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    In:  CASI
    Publication Date: 2019-07-11
    Description: The purpose of this presentation is to give you a survey of a field of aerodynamics which has for a number of years been attracting an ever growing interest. The subject is the theory of flows with friction, and, within that field, particularly the theory of friction layers, or boundary layers. As you know, a great many considerations of aerodynamics are based on the so-called ideal fluid, that is, the frictionless incompressible fluid. By neglect of compressibility and friction the extensive mathematical theory of the ideal fluid (potential theory) has been made possible.
    Keywords: Aerodynamics
    Type: NACA-TM-1217
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  • 8
    Publication Date: 2019-07-11
    Description: An investigation has been made in the Langley stability tunnel to determine the low-speed static stability and control characteristics of a model of the Bell MX-776. The results of the investigation indicated that the basic model configuration was longitudinally stable in the angle-of-attack range from about -16 deg. to 16 deg. but that the stability was a minimum near O deg angle of attack. The data indicated an aerodynamic-center position about 0.64 body diameters behind the center of gravity at low angles of attack. Reduction in the size of the front horizontal fins increased the longitudinal stability. With 20 percent of the span of the normal front horizontal fins cut off the aerodynamic center was about 1.04 body diameters behind the center of gravity, and with front horizontal fins having the same area as the front vertical fins, the aerodynamic center was 2.26 body diameters behind the center of gravity (at low angles of attack).
    Keywords: Aerodynamics
    Type: NACA-RM-SL9G08
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  • 9
    Publication Date: 2019-07-11
    Description: Rocket-powered models were flown at high-subsonic, transonic, and supersonic speeds to determine the zero-lift drag of fin-stabilized parabolic bodies of revolution differing in fineness ratio and in position of maximum diameter. The present paper presents the results for fineness ratio 12.5, 8.91 and 6.04 bodies having maximum diameters located at stations of 20, 40, 60, and 80 percent of body length. All configurations had cut-off sterns and all had equal base, frontal, and exposed fin areas. For most of the supersonic-speed range models having their maximum diameters at the 60-percent station gave the lowest values of drag coefficient. At supersonic speeds, increasing the fineness ratio generally reduced the drag coefficient for a given position of maximum diameter.
    Keywords: Aerodynamics
    Type: NACA-RM-L9I30
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  • 10
    Publication Date: 2019-07-12
    Description: A supersonic compressor design having supersonic velocity at the entrance of the stator is analyzed on the assumption of two-dimensional flow. The rotor and stator losses assumed in the analysis are based on the results of preliminary supersonic cascade tests. The results of the analysis show that compression ratios per stage of 6 to 10 can be obtained with adiabatic efficiency between 70 and 80 percent. Consideration is also given in the analysis to the starting, stability, and range of efficient performance of this type of compressor. The desirability of employing variable-geometry stators and adjustable inlet guide vanes is indicated. Although either supersonic or subsonic axial component of velocity at the stator entrance can be used, the cascade test results suggest that higher pressure recovery can be obtained if the axial component is supersonic.
    Keywords: Aerodynamics
    Type: NACA-RM-L9G06
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  • 11
    Publication Date: 2019-08-13
    Description: In the Institute for Flight Mechanics of the DVL a reactor arrangement with a maximum output of 100 kg was investigated as an expedient for the termination of dangerous spins on an airplane of the FW 56 type. reproduce the influence of a disturbance of the steady spin condition by a pitching or yawing moment. The tests were meant to reproduce the influence of a disturbance of the steady spin condition by a pitching and yawing moment.
    Keywords: Aerodynamics
    Type: NACA-TM-1221 , Zentrale fuer Wissenschaftliches Berichtswesen bei der Deutschen Versuchsanstalt fuer Luftfahrt Nr. 1027
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  • 12
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    In:  CASI
    Publication Date: 2019-07-13
    Description: When auxiliary jet engines are installed on airframes; as well as in some new designs, the jet engines are mounted in such a way that the jet stream exhausts in close proximity to the fuselage. This report deals with the behavior of the jet in close proximity to a two-dimensional surface. The experiments were made to find out whether the axially symmetric stream tends to approach the flat surface. This report is the last of a series of four partial test reports of the Goettingen program for the installation of jet engines, dated October 12, 1943. This report is the complement of the report on intake in close proximity to a wall.
    Keywords: Aerodynamics
    Type: NACA-TM-1214 , Untersuchungen und Mitteilungen; 3057
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  • 13
    Publication Date: 2019-07-13
    Description: In an earlier report UM No.1117 by Gothert,the single-source method was applied to the compressible flow around circles, ellipses, lunes, and around an elongated body of revolution at different Mach numbers and the results compared as far as possible with the calculations by Lamla ad Busemann. Essentially, it was found that with favorable source arrangement the single-source method is in good agreement with the calculations of the same degree of approximation by.Lamla and Busemann. Near sonic velocity the number of steps must be increased considerably in order to sufficiently approximate the adiabatic curve. After exceeding a certain Mach number where local supersonic fields occur already, it was no longer possible, in spite of the substantially increased number of steps, to obtain a systematic solution because the calculation diverged. This result,was interpreted to mean that above this point of divergence the symmetrical type of flow ceases to exist and changes into the unsymmetrical type characterized by compressibility shocks.
    Keywords: Aerodynamics
    Type: NACA-TM-1203 , Untersuchungen und Mitteilurgen; 1471
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  • 14
    Publication Date: 2019-07-13
    Description: The problem of the motion of an elongated body of revolution in an incompressible fluid may, as is known, be solved approximately with the aid of the distribution of sources along the axis of the body. In determining the velocity field, the question of whether the body moves uniformly or with an acceleration is no factor in the problem. The presence of acceleration must be taken into account in determining the pressures acting on the body. The resistance of the body arising from the accelerated motion may be computed either directly on the basis of these pressures or with the aid of the so-called associated masses (inertia coefficients). A different condition holds in the case of the motion of bodies in a compressible gas. In this case the finite velocity of sound must be taken into account.
    Keywords: Aerodynamics
    Type: NACA-TM-1230 , Prikladnaya Matematika I Mekhanika; 10; 4; 521-524
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  • 15
    Publication Date: 2019-07-11
    Description: Various ways were tried recently to decrease the friction drag of a body in a flow; they all employ influencing the boundary layer. One of them consists in keeping the boundary layer Laminar by suction; promising tests have been carried out. Since for large Reynolds numbers the friction drag of the laminar boundary layer is much lower than that of the turbulent boundary layer, a considerable saving in drag results from keeping the boundary layer laminar, even with the blower power required for suction taken into account. The boundary layer is kept laminar by suction in two ways: first, by reduction of the thickness of the boundary layer and second, by the fact that the suction changes the form of the velocity distribution so that it becomes more stable, in a manner similar to the change by a pressure drop. There by the critical Reynolds number of the boundary layer (USigma*/V) (sub crit) becomes considerably higher than for the case without suction. This latter circumstance takes full effect only if continuous suction is applied which one might visualize realized through a porous wall. Thus the suction quantities required for keeping the boundary layer laminar become so small that the suction must be regarded as a very promising auxiliary means for drag reduction.
    Keywords: Aerodynamics
    Type: NACA-TM-1216
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  • 16
    Publication Date: 2019-07-11
    Description: Four component measurements of 12 wings of symmetric profile having flaps with chord ratios t(sub R)/t(sub L) = 0.3 and t(sub R)/t(sub L) = 0.2 are treated in this report. As a result of the investigations, the effects of plan form and gap between fixed surface and control surface have been clarified. Lift, drag, pitching moment, and hinge moment were measured in the control-surface deflection range: -23 deg 〈 or = beta 〈 or = 23 deg and the range of angle of attack: -20 deg 〈 or = alpha 〈 or = 20 deg. Six wings with flaps of small chord (t(sub R)/t(sub L) 〈 0.1) were investigated at large flap settings.
    Keywords: Aerodynamics
    Type: NACA-TM-1206 , ZWB Forschungsbericht; Rept-552/4
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  • 17
    Publication Date: 2019-07-11
    Description: The present report describes a new method for the prediction of the flow pattern of a gas in the two-dimensional and axially symmetrical case. It is assumed that the expansion of the gas is adiabatic and the flow stationary. The several assumptions necessary of the nozzle shape effect, in general, no essential limitation on the conventional nozzles. The method is applicable throughout the entire speed range; the velocity of sound itself plays no singular part. The principal weight is placed on the treatment of the flow near the throat of a converging-diverging nozzle. For slender nozzles formulas are derived for the calculation of the velocity components as function of the location.
    Keywords: Aerodynamics
    Type: NACA-TM-1215 , Luftfahrtforschung; 91-102
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  • 18
    Publication Date: 2019-07-11
    Description: An investigation has been conducted in the Langley 20-foot free-spinning tunnel of a 1/29-scale model of the Republic XF-91 airplane with a.conventional-tail arrangement installed. Previously, tests were made on the model with a vee tail installed. The erect spin and recovery characteristics of the model were determined for the normal loading with the wing installed at various amounts of incidence. The spin investigation also included inverted-spin tests, spin-recovery-parachute tests, tests with the center of gravity moved rearward, and tests with external fuel tanks added to the model. In addition, several tail.modifications were tested,on the model in an attempt, to improve the model's spin-recovery characteristics. The results indicate that any fully developed spin obtained on the airplane with the conventional tail installed will be satisfactorily terminated if rudder reversal is accompanied by moving the ailerons with the spin (stick right in a right spin).Decreasing the wing incidence from 6deg to -2deg should have a beneficial effect on the recovery characteristics of the airplane. Recovery characteristics by normal use of controls (full rudder reversal followed by moving the elevators down) will be satisfactory if the wing incidence,of the airplane is -2deg. Installation of external fuel tanks (with or without fuel) will have a somewhat adverse effect on the recovery characteristics of the airplane, but if the recovery technique includes movement of the ailerons to full with the spin, the spin rotation will be terminated rapidly. Varying the position of the center of gravity within the limits indicated to be possible on the airplane should not affect the recovery characteristics.
    Keywords: Aerodynamics
    Type: NACA-RM-SL9E20
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  • 19
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    In:  CASI
    Publication Date: 2019-07-11
    Description: The plane problem of the vibrating airfoil in supersonic flow is dealt with and solved within the scope of a linearized theory by the method of the acceleration potential.
    Keywords: Aerodynamics
    Type: NACA-TM-1238 , ZWB Forschungsbericht Nr. 1903; Rept-1903
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  • 20
    Publication Date: 2019-07-11
    Description: A supplementary investigation on the stabilization of the Jettisonable nose section of the X-2 airplane has been conducted in the Langley 20-foot free-spinning tunnel. It was found that the nose section could be stabilized by the addition of curved fins which could be folded against the fuselage for normal flight.
    Keywords: Aerodynamics
    Type: NACA-RM-L9F22
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  • 21
    Publication Date: 2019-07-11
    Description: The characteristics of a cargo-dropping device having extensible rotating blades as load-carrying surfaces have been studied in simulated vertical descent in the Langley 20-foot free-spinning tunnel. The investigation included tests to determine the variation in vertical sinking speed with load. A study of the blade characteristics and of the test results indicated a method of dynamically balancing the blades to permit proper functioning of the device.
    Keywords: Aerodynamics
    Type: NACA-RM-L9G14
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  • 22
    Publication Date: 2019-07-12
    Description: A 0.1-size powered dynamic model of a large, high-speed flying boat was landed in Langley tank no. 1 into oncoming waves 4 feet high (full size). The model was tested with two afterbodies of differing lengths (4.12 and 6.63 beams). The short afterbody had a constant angle of dead rise of 22.5deg and a keel angle of 6.5deg. The long afterbody had warped dead rise and a keel angle of 8.5deg. The vertical accelerations were slightly greater and the maximum angular accelerations and maxim= trims were slightly less for the model with the long afterbody than for the model with -the short afterbody. A wave length of 210 feet (full size) imposed the highest accelerations on the model with either the long or the short afterbody.
    Keywords: Aerodynamics
    Type: NACA-RM-SL9B09
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  • 23
    Publication Date: 2019-07-12
    Description: The inlet wide vanes for the supersonic compressor of the XJ55-FF-1 engine were studied as a separate component in order to determine the performance prior to installation in the compressor test rig. Turning angles approached design values, and increased approximately to through the inlet Mach number range from 0.30 to choke. A sharp break in turning angle was experienced when the choke condition was reached. The total-pressure loss through the guide vanes was approximately 1 percent for the unchoked conditions and from 5 to 6 percent when choked.
    Keywords: Aerodynamics
    Type: NACA-RM-SE9E03
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  • 24
    Publication Date: 2019-07-13
    Description: During the past several years it has been necessary for aeronautical research workers to exert a good portion of their effort in developing the means for conducting research in the high-speed range. The transonic range particularly has presented a very acute problem because of the choking phenomena in wind tunnels at speeds close to the speed of sound. At the same time, the multiplicity of design problems for aircraft introduced by the peculiar flow problems of the transonic speed range has given rise to an enormous demand for detail design data. Substantial progress has been made, however, in developing the required research techniques and in supplying the demand for aerodynamic data required for design purposes. In meeting this demand, it has been necessary to resort to new techniques possessing such novel features that the results obtained have had to be viewed with caution. Furthermore, the kinds of measurements possible with these various techniques are so varied that the correlation of results obtained by different techniques generally becomes an indirect process that can only be accomplished in conjunction with the application of estimates of the extent to which the results of measurements by any given technique are modified by differences that are inherent in the techniques. Thus, in the establishment of the validity and applicability of data obtained by any given technique, direct comparisons between data from different sources are a supplement to but not a substitute for the detailed knowledge required of the characteristics of each technique and fundamental aerodynamic flow phenomena.
    Keywords: Aerodynamics
    Type: NASA-TM-X-56649 , NACA Conference on Aerodynamic Problems of Transonic Airplane Design; Sep 27, 1949 - Sep 29, 1949; Hampton, VA; United States
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  • 25
    Publication Date: 2019-07-13
    Description: Lately it has been proposed to reduce the friction drag of a body in a flow for the technically important large Reynolds numbers by the following expedient: the boundary layer, normally turbulent, is artificially kept laminar up to high Reynolds numbers by suction. The reduction in friction drag thus obtained is of the order of magnitude of 60 to 80 percent of the turbulent friction drag, since the latter, for large Reynolds numbers, is several times the laminar friction drag. In considering the idea mentioned one has first to consider whether suction is a possible means of keeping the boundary layer laminar. This question can be answered by a theoretical investigation of the stability of the laminar boundary layer with suction. A knowledge, as accurate as possible, of the velocity distribution in the laminar boundary layer with suction forms the starting point for the stability investigation. E. Schlichting recently gave a survey of the present state of calculation of the laminar boundary layer with suction.
    Keywords: Aerodynamics
    Type: NACA-TM-1205 , Schriften der Deutschen Akademie der Luftfahrtforschung; 8; 1
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