A simple dead-reckoning navigational system

Simple navigation system is designed for vehicles operating in remote locations where it is not feasible to transport extensive equipment. System consists of four main components: directional gyrocompass to establish inertial direction; odometer to measure distance; signal processor to combine measured distance and direction; and sun compass to determine initial direction

A variable-gain output feedback control design methodology

A digital control system design technique is developed in which the control system gain matrix varies with the plant operating point parameters. The design technique is obtained by formulating the problem as an optimal stochastic output feedback control law with variable gains. This approach provides a control theory framework within which the operating range of a control law can be significantly extended. Furthermore, the approach avoids the major shortcomings of the conventional gain-scheduling techniques. The optimal variable gain output feedback control problem is solved by embedding the Multi-Configuration Control (MCC) problem, previously solved at ICS. An algorithm to compute the optimal variable gain output feedback control gain matrices is developed. The algorithm is a modified version of the MCC algorithm improved so as to handle the large dimensionality which arises particularly in variable-gain control problems. The design methodology developed is applied to a reconfigurable aircraft control problem. A variable-gain output feedback control problem was formulated to design a flight control law for an AFTI F-16 aircraft which can automatically reconfigure its control strategy to accommodate failures in the horizontal tail control surface. Simulations of the closed-loop reconfigurable system show that the approach produces a control design which can accommodate such failures with relative ease. The technique can be applied to many other problems including sensor failure accommodation, mode switching control laws and super agility

Characterization of transport and magnetic properties in thin film La(0.67)(Ca(x)Sr(1-x))(0.33)MnO(3) mixtures

We have grown thin films of (100) oriented La_{0.67}(Ca_{x}Sr_{1-x})_{0.33}MnO_{3} on (100) NdGaO_{3} substrates by off-axis sputtering. We have looked at the changes in the resistivity and magnetoresistance of the samples as the Ca/Sr ratio was varied. We find that as the calcium fraction is decreased, the lattice match to the substrate decreases, and the films become more disordered, as observed in transport measurements and the variation in Curie and peak resistance temperatures. We find a correlation between the temperature independent and T^2 terms to the low temperature resistivity. The room temperature magnetoresistance exhibits a maximum as the peak temperature is increased by the substitution of Sr for Ca, and a change in the field dependence to the resistivity at room temperature is observed.Comment: 5 pages, 6 eps figures, to be published in Journal of Applied Physic

Film calibration for the Skylab/ATM S-056 X-ray telescope

The sensitometry and film calibration effort for the Skylab/ATM S-056 X-ray telescope is summarized. The apparatus and procedures used are described together with the two types of flight film used, Kodak SO-212 and SO-242. The sensitometry and processing of the flight film are discussed, and the results are presented in the form of the characteristic curves and related data. The use of copy films is also discussed

Proximity effect in Nb-Mo layered films: Transition temperature and critical current dependence on period

The behavior of the transition temperature and critical current density for a Mo/Nb repeated bilayer system as a function of the number of periods was explored. The measured values of the transition temperature are compared to the theoretical predictions for the proximity effect in the dirty limit. We find that the transition temperature does not decrease as the number of periods increase. In addition, inductive critical current density measurements also show a scaling that indicates the superconductivity properties are not dependent on the number of bilayers.Comment: 13 pages, 6 figures, to be published Journal of Applied Physic

Structural Analysis of Substrate, Reaction Intermediate, and Product Binding in Haemophilus influenzae Biotin Carboxylase

© 2015 American Chemical Society. Acetyl-CoA carboxylase catalyzes the first and regulated step in fatty acid synthesis. In most Gram-negative and Gram-positive bacteria, the enzyme is composed of three proteins: biotin carboxylase, a biotin carboxyl carrier protein (BCCP), and carboxyltransferase. The reaction mechanism involves two half-reactions with biotin carboxylase catalyzing the ATP-dependent carboxylation of biotin-BCCP in the first reaction. In the second reaction, carboxyltransferase catalyzes the transfer of the carboxyl group from biotin-BCCP to acetyl-CoA to form malonyl-CoA. In this report, high-resolution crystal structures of biotin carboxylase from Haemophilus influenzae were determined with bicarbonate, the ATP analogue AMPPCP; the carboxyphosphate intermediate analogues, phosphonoacetamide and phosphonoformate; the products ADP and phosphate; and the carboxybiotin analogue N1′-methoxycarbonyl biotin methyl ester. The structures have a common theme in that bicarbonate, phosphate, and the methyl ester of the carboxyl group of N1′-methoxycarbonyl biotin methyl ester all bound in the same pocket in the active site of biotin carboxylase and as such utilize the same set of amino acids for binding. This finding suggests a catalytic mechanism for biotin carboxylase in which the binding pocket that binds tetrahedral phosphate also accommodates and stabilizes a tetrahedral dianionic transition state resulting from direct transfer of CO2 from the carboxyphosphate intermediate to biotin

Kinematic Comparison of Dolphin Kicking Performed in a Prone and Supine Body Position

Underwater dolphin kicking has become an essential element in competitive swimming but little research has been performed to provide an understanding of this movement. PURPOSE: To examine hip and knee kinematics of prone and supine dolphin kicking as they relate to speed. METHODS: Six collegiate swimmers (1.77±0.07 m, 72.4±7.6 kg, 19.8±1.0 yrs) experienced with dolphin kicking completed six 10 m maximal effort underwater kicking trials; three trials in a prone position and three trials in a supine position. An underwater camera was calibrated using a projective scaling technique and subsequently used to record each trial at 60 Hz. Twelve body landmarks were digitized from the video recordings to determine whole body center of mass location and hip and knee joint angles. Data were filtered using a fourth order Butterworth low-pass digital filter with cutoff frequencies individually determined for each coordinate or each landmark. Linear velocity of the center of mass was computed using the first central difference method. Hip and knee joint ranges of motion (ROM) were compared between body positions using a 2x2 (joint x body position) repeated measures ANOVA. Kick rate (KR) and horizontal velocity of the center of mass were compared between body positions using a two-tailed dependent t-test. RESULTS: Neither horizontal velocity (t(4)=0.308, p=0.774) nor kicking rate (t(4)=0.371, p=0.730) were different between body positions (Table 1). ROM was significantly greater in the knee than the hip (F(1,4)=110.967, p 2=0.965). ROM was not affected by body position (F(1,4)=1.068, p=0.36, 2=0.211). ROM did not interact between joint and body position (F(1,4)=1.461, p=0.818, 2=0.015). CONCLUSION: Despite some recent suggestions that a supine dolphin kick may be more effective than a prone dolphin kick, no kinematic difference were observed in this sample of swimmers. Table 1. Dolphin Kicking Kinematics. PRONE SUPINE KNEE ROM (degrees) 69.7±4.5 73.6.7±6.7 HIP ROM (degrees) 37.7±8.3 40.5±9.0 HORIZONTAL VELOCITY (m/s) 1.82±1.13 1.80±1.04 KICK RATE (kicks/min) 135.0±71.9 136.4±67.