Solar cell angular position transducer

An angular position transducer utilizing photocells and a light source is disclosed. The device uses a fully rotatable baffle which is connected via an actuator shaft to the body whose rotational displacement is to be measured. The baffle blocks the light path between the light source and the photocells so that a constant semicircular beam of light reaches the photocells. The current produced by the photocells is fed through a resistor, a differential amplifier measures the voltage drop across the resistor which indicates the angular position of the actuator shaft and hence of the object

Intermediate Biblical Greek Reader: Galatians and Related Texts

After completing basic biblical Greek, students are often eager to continue to learn and strengthen their skills of translation and interpretation. This intermediate graded reader is designed to meet those needs. The reader is “intermediate” in the sense that it presumes the user will have already learned the basics of Greek grammar and syntax and has memorized Greek vocabulary words that appear frequently in the New Testament. The reader is “graded” in the sense that it moves from simpler translation work (Galatians) towards more advanced readings from the book of James, the Septuagint, and from one of the Church Fathers. In each reading lesson, the Greek text is given, followed by supplemental notes that offer help with vocabulary, challenging word forms, and syntax. Discussion questions are also included to foster group conversation and engagement. There are many good Greek readers in existence, but this reader differs from most others in a few important ways. Most readers offer text selections from different parts of the Bible, but in this reader the user works through one entire book (Galatians). All subsequent lessons, then, build off of this interaction with Galatians through short readings that are in some way related to Galatians. The Septuagint passages in the reader offer some broader context for texts that Paul quotes explicitly from the Septuagint. The Patristic reading from John Chrysystom comes from one of his homilies on Galatians. This approach to a Greek reader allows for both variety and coherence in the learning process. Other unique features within this intermediate Greek reader include a set of word studies for important Greek words in Galatians, a discussion of the basics of textual criticism, and a brief glossary of syntax and key concepts in biblical Greek. This reader is a collaborative project that developed out of an advanced Greek course at Portland Seminary (2017-2018). The following students contributed equally to the content of the textbook. Alexander Finkelson (MATS, Portland Seminary, 2018) Bryn Pliska Girard (MATS, Portland Seminary, 2018) Charles E. R. Jesch (MDIV, Portland Seminary, current student) Paul C. Moldovan (MDIV, Portland Seminary, current student) Jenny E. Siefken (MATS, Portland Seminary, current student) Julianna Kaye Smith (MATS, Portland Seminary, 2018) Jana Whitworth (MDIV, Portland Seminary, current student) Kyle J. Williams (MATS, Portland Seminary, 2018)https://digitalcommons.georgefox.edu/pennington_epress/1001/thumbnail.jp

Status of two studies on active control of aeroelastic response

The application of active control technology to the suppression of flutter has been successfully demonstrated during two recent studies in the Langley transonic dynamics tunnel. The first study involved the implementation of an aerodynamic-energy criterion, using both leading- and trailing-edge controls, to suppress flutter of a simplified delta-wing model. Use of this technique has resulted in an increase in the flutter dynamic pressure of approximately 12 percent for this model at a Mach number of 0.9 Analytical methods used to predict the open- and closed-loop behavior of the model are also discussed. The second study, was conducted to establish the effect of active flutter suppression on a model of the Boeing B-52 Control Configured Vehicle (CCV). Some preliminary results of this study indicate significant improvements in the damping associated with the critical flutter mode

Experimental parametric studies of transonic T-tail flutter

Wind-tunnel tests of the T-tail of a wide-body jet airplane were made at Mach numbers up to 1.02. The model consisted of a 1/13-size scaled version of the T-tail, fuselage, and inboard wing of the airplane. Two interchangeable T-tails were tested, one with design stiffness for flutter-clearance studies and one with reduced stiffness for flutter-trend studies. Transonic antisymmetric-flutter boundaries were determined for the models with variations in: (1) fin-spar stiffness, (2) stabilizer dihedral angle (-5 deg and 0 deg), (3) wing and forward-fuselage shape, and (4) nose shape of the fin-stabilizer juncture. A transonic symmetric-flutter boundary and flutter trends were established for variations in stabilizer pitch stiffness. Photographs of the test configurations are shown

Transonic calculations for a flexible supercritical wing and comparison with experiment

Pressure data measured on the flexible DAST ARW-2 wing are compared with results calculated using the transonic small perturbation code XTRAN3S. A brief description of the analysis is given and a recently-developed grid coordinate transformation is described. Calculations are presented for the rigid and flexible wing for Mach numbers from 0.60 to 0.90 and dynamic pressures from 0 to 1000 psf. Calculated and measured static pressures and wing deflections are compared, and calculated static aeroelastic trends are given. Attempts to calculate the transonic instability boundary of the wing are described

Transonic flutter study of a 50.5 deg cropped-delta wing with two rearward-mounted nacelles

Transonic flutter characteristics of three geometrically similar delta-wing models were experimentally determined in the Langley transonic dynamics tunnel at Mach numbers from about 0.6 to 1.2. The models were designed to be simplified versions of an early supersonic transport wing design. The model was an aspect-ratio-1.28 cropped-delta wing with a leadingedge sweep of 50.5 deg. The flutter characteristics obtained for this wing configuration indicated a minimum flutter-speed index near a Mach number of 0.92 and a transonic compressibility dip amounting to about a 27-percent decrease in the flutter-speed index relative to the value at a Mach number of 0.6. Analytical studies were performed for one wing model at Mach numbers of 0.6, 0.7, 0.8, and 0.9 by using both doublet-lattice and lifting-surface (kernel-function) unsteady aerodynamic theory. A comparison of the analytical and experimental flutter results showed good agreement at all Mach numbers investigated

Integration of children with severe and multiple disabilities into regular pre-school and school settings

Thesis (M.A.) -- University of Adelaide, Dept. of Psychology, 199

Development and demonstration of a flutter-suppression system using active controls

The application of active control technology to suppress flutter was demonstrated successfully in the transonic dynamics tunnel with a delta-wing model. The model was a simplified version of a proposed supersonic transport wing design. An active flutter suppression method based on an aerodynamic energy criterion was verified by using three different control laws. The first two control laws utilized both leading-edge and trailing-edge active control surfaces, whereas the third control law required only a single trailing-edge active control surface. At a Mach number of 0.9 the experimental results demonstrated increases in the flutter dynamic pressure from 12.5 percent to 30 percent with active controls. Analytical methods were developed to predict both open-loop and closed-loop stability, and the results agreed reasonably well with the experimental results

Measured unsteady transonic aerodynamic characteristics of an elastic supercritical wing with an oscillating control surface

Transonic steady and unsteady aerodynamic data were measured on a large elastic wing in the NASA Langley Transonic Dynamics Tunnel. The wing had a supercritical airfoil shape and a leading-edge sweepback of 28.8 deg. The wing was heavily instrumented to measure both static and dynamic pressures and deflections. A hydraulically driven outboard control surface was oscillated to generate unsteady airloads on the wing. Representative results from the wind tunnel tests are presented and discussed, and the unexpected occurrence of an unusual dynamic wing instability, which was sensitive to angle of attack, is reported