Integrated technology rotor/flight research rotor concept definition study

As part of the Integrated Technology Rotor/Flight Research Rotor (ITR/FRR) Program a number of advanced rotor system designs were conceived and investigated. From these, several were chosen that best meet the started ITR goals with emphasis on stability, reduced weight and hub drag, simplicity, low head moment stiffness, and adequate strength and fatigue life. It was concluded that obtaining low hub moment stiffness was difficult when only the blade flexibility of bearingless rotor blades is considered, unacceptably low fatigue life being the primary problem. Achieving a moderate hub moment stiffness somewhat higher than state of the art articulated rotors in production today is possible within the fatigue life constraint. Alternatively, low stiffness is possible when additional rotor elements, besides the blades themselves, provide part of the rotor flexibility. Two primary designs evolved as best meeting the general ITR requirements that presently exist. An I shaped flexbeam with an external torque tube can satisfy the general goals but would have either higher stiffness or reduced fatigue life. The elastic gimbal rotor can achieve a better combination of low stiffness and high fatigue life but would be a somewhat heavier design and possibly exhibit a higher risk of aeromechanical instability

The Hydrogendifluoride Anion in an Asymmetric Crystalline Environment: The Crystal and Molecular Structure of Trithioureatellurium(II) Di(Hydrogendifluoride)

The crystal structure of Te[CS(NH2l2h(FHF)2, I , was determined at 133K using single crystal x-ray diffraction techniques. A total of 6042 independent reflections were observed for the monoclinic crystals (space group P21/c, No. 14, a = 0.5846(3), b = 2.046(1), c = 1.1433(7) nm, (J = 94.69(5) 0 , Ve= 1.363(1) nm3, (Z = 4), in the range 4.0° s 219 s 70.0° of which 5243 had F0 2 > 3a (F0 2). The trithiourea- tellurium (II) molecules crystallize as dimeric distorted square planar cations [Te(tu)3]24+ (tu = thiourea) located about an inversion center. The cations are linked by N-H ... F hydrogen bonds. The environment about the two independent (FHFt anions is decidedly asymmetric and therefore the hydrogen atoms are not centered between the fluorine atoms

Unsur Intrinsik dalam Legenda Ulai Bujang Karem Sastra Lisan Dayak Ketungau Sesaek Kabupaten Sekadau

This research aim to analyzing theme, mandate, plot, character, and background in the legend Ulai Bujang Karem Oral Literature Dayak Ketungau Sesaek Sekadau, and describing implementation plan this study into learning Indonesian in the schools. The method used in this study is descriptive method. Based on the analysis of data can be concluded that the legend Ulai Bujang Karem there are theme, mandate, plot, character, and background. This result is expected being Indonesian study materials in the school especially to teach students to analyzing intrinsic element in a story. The learning is guided by the lesson plan that is suitable with the condition and situation with the school learning environment. Keywors: intrinsic element, legend, oral literatur

Dynamic Simulations of a Large High-Frequency Power System

Dynamic simulations to assess performance aspects of a large high-frequency power system have been conducted. The analysis uses a model of an 80-MW power system for an all-electric ship. The model, developed in the Matlab/Simulink environment, includes several power generation units, two propulsion power trains, an energy storage system, a high-power pulse load, and several service loads. Three case studies were addressed. The first considers the response of the power system to a high-power step load, representing a sudden request for acceleration of the ship. The second deals with the effects of a partial loss of generation during operation. The third addresses the effects of load drop on the power system.Center for Electromechanic

Development of a Monochromator System for the APS X-Ray BESSRC Beamlines

The authors have designed a double crystal, fixed exit monochromator which allows windowless operation of the APS beamlines. The crystals are mounted on a turntable with the first crystal at the center of rotation. A mechanical linkage is used to correctly position the second crystal and maintain a constant offset. The monochromator is designed with two adjacent vacuum chambers, one containing the drive mechanism, a vacuum compatible Huber goniometer, and another chamber containing a turntable on which the monochromator linkage and crystals are mounted. The small annular opening around a hollow stainless steel shaft which connects the Huber goniometer to the turntable is the only passage between the two adjacent chambers. The design of the monochromator is such that it can accommodate water, liquid nitrogen or galium cooling for the crystal optics. The basic design for the monochromator linkage mechanism is presented along with details of the monochromator chamber. The results of initial optical tests of the monochromator system using tilt sensors and a precision autocollimator will also be given

Why cryogenically cooled, thin crystals handle extremely high power densities

Recently, a new type of cryogenically cooled high heat load monochromator was proposed and, developed at Argonne National Laboratory and tested at European Synchrotron Radiation Facility (ESRF.) These tests showed that powers of 153 W and power densities of 450 W/mm{sup 2} cause only negligible strain. These powers and power densities are larger than will be absorbed by the first crystal on an undulator beamline at the Advanced Photon Source (APS). In our earlier work we suggested that the crystal might show strain at much lower values of the powers and power densities. We now can explain the ESRF results in terms of the unique role the negative thermal expansion coefficient of Si plays in minimizing strain

High heat load crystal cooling strategies for an APS wiggler beamline

High energy wigglers produce extremely high total powers. For example, the insertion device for one beamline of the Basic Energy Sciences Synchrotron Research Center (BESSRC) is an elliptical multipole wiggler (EMPW) which can generate circularly polarized X-rays on axis and produces a total power of {approximately}8 kW. This insertion device will be used to simultaneously provide x-rays to three branch lines, a branch equipped with a normal double crystal monochromator feeding a scattering and spectroscopy station, and two branches with single-bounce horizontally deflecting monochromators for Compton scattering and High Energy Diffraction. The crystal optics for this type of device require substantially different heat load solutions than those used for undulator beamlines. We will discuss how the beam is split and shared among the beamline branch lines and present the crystal cooling strategies employed for both the double-crystal monochromator and horizontally deflecting single-bounce monochromators

Factorial Economic Planning Applied to Agricultural Experimentation

Innovation may be limited by the scarceness of resources, such as financial, homogeneous area, skilled labor or other research needs, for example the difficulty in experimental control of large areas in the field. In research areas such as chemistry and physics, designs are used in such a way that when compared to the agronomic designs, they result in a reduced number of experimental units, which in this work are called economic designs. Thus, the objective of this study was to identify significant factors and effects (p-valu

Bearing Loads in a Vehicular Flywheel Battery

Radial and axial rotor support bearings are critical elements in flywheel batteries for vehicle applications. This paper discusses the quantification of bearing loads required for the development of optimal bearing designs, particularly magnetic bearings. The primary contributors to bearing loads are shown to be vehicle shock, vibration, maneuvering, and gyrodynamics. Emphasis is placed on transit bus applications. Available data for each is presented, including actual measurements made on buses, and a detailed analysis of gyrodynamics.Center for Electromechanic