An aerodynamic comparison of blown and mechanical high lift airfoils

Short takeoff and landing (STOL) performance utilizing a circulation control airfoil was successfully demonstrated on the A-6 CCW (circulation control wing). Controlled flight at speeds as slow as 67 knots was demonstrated. Takeoff ground run and liftoff speed reductions in excess of 40 and 20 percent respectively were achieved. Landing ground roll and approach speeds were similarly reduced. The technology demonstrated was intended to be useable on modern high performance aircraft. STOL performance would be achieved through the combination of a 2-D vectored nozzle and a circulation control type of high lift system. The primary objective of this demonstration was to attain A-6 CCW magnitude reductions in takeoff and landing flight speed and ground distance requirements using practical bleed flow rates from a modern turbofan engine for the blown flap system. Also, cruise performance could not be reduced by the wing high lift system. The A-6 was again selected as the optimum demonstration vehicle. The procedure and findings of the study to select the optimum high lift wing design are documented. Some findings of a supercritical airfoil and a comparison of 2-D and 3-D results are also described

The effect of combined glutamate receptor blockade in the NTS on the hypoxic ventilatory response in awake rats differs from the effect of individual glutamate receptor blockade.

Ventilatory acclimatization to hypoxia (VAH) increases the hypoxic ventilatory response (HVR) and causes persistent hyperventilation when normoxia is restored, which is consistent with the occurrence of synaptic plasticity in acclimatized animals. Recently, we demonstrated that antagonism of individual glutamate receptor types (GluRs) within the nucleus tractus solitarii (NTS) modifies this plasticity and VAH (J. Physiol. 592(8):1839-1856); however, the effects of combined GluR antagonism remain unknown in awake rats. To evaluate this, we exposed rats to room air or chronic sustained hypobaric hypoxia (CSH, PiO2 = 70 Torr) for 7-9 days. On the experimental day, we microinjected artificial cerebrospinal fluid (ACSF: sham) and then a "cocktail" of the GluR antagonists MK-801 and DNQX into the NTS. The location of injection sites in the NTS was confirmed by glutamate injections on a day before the experiment and with histology following the experiment. Ventilation was measured in awake, unrestrained rats breathing normoxia or acute hypoxia (10% O2) in 15-min intervals using barometric pressure plethysmography. In control (CON) rats, acute hypoxia increased ventilation; NTS microinjections of GluR antagonists, but not ACSF, significantly decreased ventilation and breathing frequency in acute hypoxia but not normoxia (P < 0.05). CSH increased ventilation in hypoxia and acute normoxia. In CSH-conditioned rats, GluR antagonists in the NTS significantly decreased ventilation in normoxia and breathing frequency in hypoxia. A persistent HVR after combined GluR blockade in the NTS contrasts with the effect of individual GluR blockade and also with results in anesthetized rats. Our findings support the hypotheses that GluRs in the NTS contribute to, but cannot completely explain, VAH in awake rats

Interim Report December 1952-March 1953

Change Order "O" to Contract NOy-12561, under which the Laboratory is now operating, provides as a general objective the investigation of the forces and pressures exerted by waves on fixed plane barriers inclined at any angle to the sea surface, and on stepped or off-set plane barriers. In keeping with this objective, the Laboratory is endeavoring to develop a program which will combine a basic investigation of the mechanics of wave-induced forces with the production of immediately useful data. It is expected, for instance, that the results of experimental farce and pressure measurements on plane barriers, aside from their scientific value, can be used with profit in calculating the stability of gravity-type or caisson breakwaters against sliding and overturning. Since this program represents a new field of work for this Laboratory, the initial portion of the contract period has been devoted to the alteration of existing laboratory equipment, and the design and construction of required new equipment. In all of the~ modification and development of force and pressure measuring equipment, an effort has been made to design for maximum flexibility. Thus, the resulting basic units can be easily adapted to the various specific phases of the current or future investigations, such as breaking and non-breaking wave conditions, and many configurations of structures for which force or pressure data will be of interest. At this time, all equipment for the pressure measuring and orbit investigation programs has been completed, and work on these programs has begun. The force measuring apparatus is under construction, with completion estimated as June 1, 1953. In view of the considerable investment in time and funds made to equip the Laboratory for this new type of investigation, this report has been prepared to describe in some detail the alteration of existing equipment and the development of new equipment

The evolution of pebble size and shape in space and time

We propose a mathematical model which suggests that the two main geological observations about shingle beaches, i.e. the emergence of predominant pebble size ratios and strong segregation by size are interrelated. Our model is a based on a system of ODEs called the box equations, describing the evolution of pebble ratios. We derive these ODEs as a heuristic approximation of Bloore's PDE describing collisional abrasion. While representing a radical simplification of the latter, our system admits the inclusion of additional terms related to frictional abrasion. We show that nontrivial attractors (corresponding to predominant pebble size ratios) only exist in the presence of friction. By interpreting our equations as a Markov process, we illustrate by direct simulation that these attractors may only stabilized by the ongoing segregation process.Comment: 22 pages, 8 figure

Investigation of inductively coupled plasma mass spectrometry with ultrasonic nebulization and membrane desolvation sample introduction as a liquid chromatography detector for heteroatom-containing pharmaceutical compounds

Includes bibliographical references (pages [215]-221).Inductively coupled plasmas (ICPs) efficiently excite and ionize metals and semi-metals allowing for their detection by atomic emission spectroscopy (AES) or mass spectrometry (MS). Nonmetal analytes are more difficult to detect due to their higher excitation and ionization energies. The sensitive detection of nonmetal analytes is becoming increasingly important in the pharmaceutical industry as new drug compounds and impurities containing nonmetals are being developed. These compounds are typically detected after they are separated by high performance liquid chromatography (HPLC). The research presented in this dissertation investigates the application of ultrasonic nebulization and membrane desolvation (USN-MD) with ICP-MS and ICP-AES as detectors for nonmetal analytes speciated by HPLC. A study identified which HPLC mobile phases and buffers lead to sensitive determinations for a phosphorus-containing analyte with ICP-AES and ICP-MS detection. For ICP-AES detection, neither large signal enhancements nor degradations were observed for the buffers and mobile phase combinations tested. It was determined that gradient elution could be performed with USN-MD-ICP-AES detection. For ICP-MS detection, effects of these buffers were more significant. A large decrease in sensitivity was noted when the mobile phase included organic solvents. Isocratic elution conditions are suggested when USN-MD-ICP-MS detection is utilized. The addition of supplemental gases to the nebulizer gas flow of an ICP-MS was also investigated. For oxygen addition, signal degradation was noted for sulfur-, phosphorus-, and chlorine-containing analytes. It was determined that 6 % oxygen in the nebulizer gas flow yielded efficient removal of carbon while not appreciably increasing detection limits. With nitrogen addition, a large increase in the background signal was found for phosphorus determinations. A decrease in sensitivity was found when determining sulfur. Helium addition did not produce significant deviations from standard argon ICP behavior, indicating that it is not being significantly ionized. A final study utilized ICP-MS as a detector for the separation of several model analyte systems. It was found that significant band broadening occurred for several volatile analytes, reducing sensitivity and negatively affecting chromatographic figures of merit. However, nonvolatile analytes yielded sensitive determinations.Ph.D. (Doctor of Philosophy

Interim Report

Recent experimental work has concentrated on the study of resultant force and pressure distribution on the stepped barrier designated as Case 5 (W. M. Simpson, Serial 1057, 6 Aug 1953 / J. H . Carr). Case 5 barrier has a plane vertical front face extending the two feet from bottom to still-water surface. Above still-water level are five steps, each of 2. 4-in. rise and tread. These dimensions, to a 20:1 scale, represent the prescribed prototype depth of 40 feet and the rise and tread of four feet each. The separate model barriers for resultant force and for pressure distribution measurements are each cast of aluminum. Vertical ribs at the rear provide rigidity and serve as convenient mounting surfaces

Determination of Active Pharmaceutical Ingredients by Heteroatom Selective Detection Using Inductively Coupled Plasma Mass Spectrometry with Ultrasonic Nebuilization and Membrane Desolvation Sample Introduction

The combination of ultrasonic nebulization with membrane desolvation (USN-MD) is utilized to determine active pharmaceutical ingredients (API) by heteroatom inductively coupled mass spectroscopy (ICP-MS) detection. Ultrasonic nebulization provides efficient sampling while use of the membrane desolvator acts to reduce solvent-based interferences. This approach reduces interferences sufficiently so that a standard argon ICPquadrupole MS can be utilized. Examined APIs and associated heteroatoms included: phosphomycin (P), amoxicillin (S), chlorpropamide (Cl), and ofloxacin (F). The optimum plasma r.f. powers for P, S, and Cl were in the 1000 to 1200 watts range. The high ionization energy of F required that the plasma be operated at 1500W. The 16O2 þ interference at mass 32 precluded determinations using the sulfur-32. The sulfur-34 (4.2% natural isotopic abundance), however, was relatively free of isobaric interferences. Interferences were relatively small at the mass 35 isotope of Cl, but increased with higher ICP r.f. powers. Overlaps were significant at the masses of monoisotopic species, fluorine-19 and phosphorus-31. Detection limits for P, S, Cl, and F of 2, 3, 90, and 3000 ng/mL, respectively, were generally lower than those produced with other quadrupole systems and comparable to or better than values published utilizing high-resolution instruments