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Unit adjustable to resistances up to 35 ohms. Adjustable, audible electrical-continuity tester gives audible indication. Used safely on circuit boards in which semiconductor components installed, and on complementary metal oxide/semiconductor integrated circuits. Tester compact and circuit simple. Built from inexpensive standard components.
The first documented wind tunnel employing a flexible walled test section for the purpose of eliminating wall interference was constructed in England by the National Physical Laboratory (NPL) during the late 1930's. The tunnel was transonic and designed for two-dimensional testing. In an attempt to eliminate the top and bottom wall interference effects on the model NPL developed a strategy to adjust two flexible walls to streamlined shapes. This report covers an evaluation of the NPL wall adjustment strategy in a modern wind tunnel, e.g., the Transonic Self-Streamlining Wind Tunnel (TSWT) at the University of Southampton, England. The evaluation took the form of performance comparisons with other modern strategies which have been developed for use in, and proven in, the TSWT.
An improvement is presented for the 2-D strategies for adjustment of the flexible top and bottom walls of an Adaptive (Wind Tunnel) Wall Test Section (AWTS). This adjustment is part of the wall adaptation process to eliminate top and bottom wall interference at the source. The improvements to account for second order effects are described in mathematical detail. It is intended that these improvements should further minimize the necessary iterations in the wall adaptation process. An associated computer program written in BASIC is presented and several test cases run with this program are discussed. The strategy performs well for a theoretical test case but when applied to experimental AWTS data some discrepancies in the adapted wall shapes are found.
Probe readily positionable in core of uniform flow in hypersonic wind tunnel. Formed of pair of mating cylindrical housings: transducer housing and pitot-tube housing. Pitot tube supported by adjustable wedge fairing attached to top of pitot-tube housing with semicircular foot. Probe adjusted both radially and circumferentially. In addition, pressure-sensing transducer cooled internally by water or other cooling fluid passing through annulus of cooling system.
The design and performance of the first traveling-wave tube (TWT) to be built with a phase-adjusted taper (PAT) is discussed. By adjusting the phase of the electron bunch with respect to the RF wave for strong electron bunch formation at the beginning of the taper and strong power conversion at the end, the PAT achieves a high efficiency of power conversion from the electron beam to the RF wave. A PAT incorporated into the output section of a baseline 29-30 GHz ferruleless coupled-cavity TWT experimentally increased the peak RF power from 420 to 1000 W and the peak RF interaction efficiency from 9.6 to 22.6 percent.
Modified adjustable-grip-length quick-release pin holds two bodies together. Threaded shaft of pin threaded in floating nut to pretension fastener. Pin connects and disconnects rapidly and adjusted to accommodate small differences between thicknesses of nominally identical sets of parts to be attached to each other.
In structure of improved coupled-cavity traveling-wave tube amplifier, lengths of cavities chosen according to computer-generated, nonlinear taper to increase efficiency of conversion of power from electron beam to microwave. Design calls for "phase-adjusted taper," calculated so phase of electron bunches with respect to phase of microwave changes gradually from value conducive to formation of strong bunches to value conducive to strong transfer of power to microwave at output of taper. Phase-adjusted taper significantly increases power capability of microwave transmission, enabling satellite-communication systems to have higher data-transmission rates.
Actuators apply stresses to generate distortions counteracting undesired distortions in technique for adjusting curvature of large focusing mirror or lens. Motor-and-gear assemblies under remote control vary squeeze of ring clamp and push or pull of hollow shaft to make fine adjustments in curvature of mirror. Applicable to large astronomical-telescope mirrors with diameters of 60 cm or more.
An efficient direct algorithm of convective adjustment for an arbitrary critical value of the vertical temperature lapse rate gamma is proposed. The algorithm provides an exact and unique solution of a standard convective adjustment problem for models with temperature specified either on nonuniformly spaced levels or for layers of different thicknesses in pressure, sigma, or other vertical coordinate related to pressure. The algorithm may be recommended for use either directly in atmospheric models not explicitly including a hydrologic cycle with prescribed gamma, or as a part of more complicated parameterizations of moist convection, where gamma may be calculated depending on relative humidity.
The concept of baroclinic adjustment is reexamined in the context of a fully nonlinear two-layer model on a beta-plane. Based on the results, a single, conceptually very simple mechanism of the nonlinear equilibration of waves and the mean flow is proposed, which is termed 'nonlinear baroclinic adjustment'. The new concept appears applicable to cases that currently require different explanations, varying from case to case, to account for the equilibration of the mean temperature gradient in the presence of external driving.
Attachment for plasma spray gun provides four degrees of freedom for adjustment of position and orientation at which powder injected externally into plasma flame. Manipulator provides for adjustment of pitch angle of injection tube: set to inject powder at any angle ranging from perpendicular to parallel to cylindrical axis. Scribed lines on extension bar and manipulator indicate pitch angle of extension tube. Collar changed to adapt injector to different gun.
The efficient performance of an airplane requires that certain adjustments be made as the density of the air through which the airplane passes changes. The safety of the over-dimensioned aircraft engine depends upon careful manipulation of spark advance and throttle opening and a proper control of a variable pitch propeller, if the maximum performance of the supercharged engine is to be obtained. It is evident that there is a real need for satisfactory devices to make such adjustments automatically. Discussed here is a method of automatic compensation which deserves consideration in the design of such devices. Existing schemes for automatic compensation all depend upon some contrivance which functions primarily because of changes in atmospheric pressure. In these devices a leak in the supposedly tight chamber means utter failure. The elimination of this source of danger is one of the aims of the method of altitude compensation described here. The change suggested is to make the source of operation the difference between atmospheric pressure and some multiple of atmospheric pressure instead of the difference between the atmospheric pressure and that of the gas confined in a tight chamber. The design of a device based on this method of altitude compensation is given.
The performance of a turbojet engine with a two-stage turbine, an adjustable first-stage turbine stator, and a variable-area exhaust nozzle was investigated at selected constant engine speeds and two simulated flight conditions. For the particular component characteristics of the engine investigated, little improvement in thrust levels of interest by use of an adjustable rather than an optimum fixed first-stage turbine stator.
For turbojet engines designed for flight Mach numbers of 2.5 and 3.0, use of turbine stator adjustment to maintain compressor design-point operation was evaluated analytically to determine the effect on the aerodynamics of the turbine. Since the effect of turbine stator adjustment is to make the turbine design sensitive to the particular engine design conditions selected, in some cases the turbine must be conservatively designed for the high-speed flight condition to assure satisfactory turbine performance at take-off. A new concept, the break-even point, is introduced to provide quick evaluation of the proximity of turbines to the blade-loading limit at any off-design operation.
Microwave transversal filters implemented as adjustable tapped fiber optic delay lines developed. Main advantages of these filters (in comparison with conventional microwave transversal filters) are small size, light weight, no need for matching of radio-frequency impedances, no need for shielding against electromagnetic radiation at suboptical frequencies, no need for mechanical tuning, high stability of amplitude and phase, and active control of transfer functions. Weights of taps in fiber optic delay lines adjusted.
Improved mount for lens or mirror in laser offers rigidity similar to that of nonadjustable optical mount. In comparison with older adjustable optical mounts, this one less susceptible to movements and distortions caused by vibrations and by thermal expansions and contractions. Mount contains neither adjustment rods (which grow or shrink as temperature varies) nor springs (which transmit vibrations to mounted optic).
Periodic gain adjustment in plants of irreducible order, n, or for equalization of communications channels is effected in such a way that the plant (system) appears to be minimum phase by choosing a horizon time N is greater than n of liftings in periodic input and output windows rho sub u and rho sub y, respectively, where N is an integer chosen to define the extent (length) of each of the windows rho sub u and rho sub y, and n is the order of an irreducible input/output plant. The plant may be an electrical, mechanical, or chemical system, in which case output tracking (OT) is carried out for feedback control or a communication channel, in which case input tracking (IT) is performed. Conditions for OT are distinct from IT in terms of zero annihilation, namely H(sub s)H(sub s)(sup +) = I for OT and H(sub s)H(sub s)(sup +) = I of IT, where the OT conditions are intended for gain adjustments in the control system, and IT conditions are intended for equalization for communication channels.
An adjustable mechanical end joint system for connecting structural column elements and eliminating the possibility of free movement between joint halves during loading or vibration has a node joint body having a cylindrical engaging end and a column end body having a cylindrical engaging end. The column end joint body has a compressible preload mechanism and plunger means housed therein. The compressible preload mechanism may be adjusted from the exterior of the column end joint body through a port.