CSI Flight Computer System and experimental test results

This paper describes the CSI Computer System (CCS) and the experimental tests performed to validate its functionality. This system is comprised of two major components: the space flight qualified Excitation and Damping Subsystem (EDS) which performs controls calculations; and the Remote Interface Unit (RIU) which is used for data acquisition, transmission, and filtering. The flight-like RIU is the interface between the EDS and the sensors and actuators positioned on the particular structure under control. The EDS and RIU communicate over the MIL-STD-1553B, a space flight qualified bus. To test the CCS under realistic conditions, it was connected to the Phase-0 CSI Evolutionary Model (CEM) at NASA Langley Research Center. The following schematic shows how the CCS is connected to the CEM. Various tests were performed which validated the ability of the system to perform control/structures experiments

Elementary School Principal Inservice: Practices And Perceptions Related To Pupil Academic Achievement Among Selected California School Districts (Staff Development)

Purpose. The purpose of this investigation was to determine the relationships that exist between current practices employed by California school districts to provide inservice training for elementary principals and pupil academic achievement. Procedure. The extreme high and low school districts with respect to pupil academic achievement were identified using 1981 district scores and comparison score bands for the California Assessment Program, grade six test. The superintendents in all of the districts and all principals in a systematically selected sample of those districts were surveyed by mail to determine practices, policies and perceptions pertaining to inservice training for elementary principals. Content of the survey instruments was based on the recommendations from the Managers Report and research validated characteristics of effective inservice programs. Differences and relationships between the high and low achieving districts were determined using t-tests, point-biserial and Pearson product-moment correlations. Findings. In general, there was found to be no significant difference or relationship between district achievement level and the policies, practices and perceptions pertaining to principal inservice among either the district administrators or the principals. Based on five components on the principals\u27 survey, however, there was an indication that the principals in the high achieving districts perceive themselves to be more involved in planning, conducting and participating in inservice training activities than those in the low achieving districts. Implications for Further Study. (1) Replicate the study of principals\u27 perceptions using a larger sample or another method for selecting the sample. (2) Apply statistical methods to the data collected for this study to determine within group differences among the inservice components. (3) Explore the specifics of principal involvement in inservice planning and decision-making. (4) Replicate this study based on the identification of the high and low achieving schools throughout the state rather than districts. (5) Explore other variables which may differentiate the high from the low achieving districts (e.g., principals\u27 experience, training, administrative structure of the district, economic base of the area in which the district is located)

Initial test results on state estimation on the SCOLE mast

Modal state estimation tests are performed on the SCOLE mast for the fixed Shuttle platform case. Kalman filter state estimation results from a five mode computer model of the SCOLE mast, developed from a finite element analysis, are compared with those state estimates obtained from laboratory tests. Two comparison runs are presented, one an excitation of the first two bending modes, another, an excitation of the first torsional mode of the mast. Results from both runs show poor agreement in modal estimation between the computer model simulations and the laboratory test data. At present, the reason(s) for this poor performance is unknown. Both the laboratory hardware and software and the computer model are being checked for possible sources of errors. Further computer simulations as well as laboratory testing will be performed

A ROTTERDAM APPLICATION TO INTERNATIONAL TRADE IN FRESH APPLES: A DIFFERENTIAL APPROACH

A Rotterdam import allocation model is used to fit import data for fresh apples in four importing markets important to U.S. apple exporters. Nested tests rejected homotheticity but could not reject homogeneity, symmetry, or separability among import suppliers. A Monte Carlo test rejected first-order autocorrelation in each market. Expenditure and price elasticities are calculated and reported.International Relations/Trade,

CSI computer system/remote interface unit acceptance test results

The validation tests conducted on the Control/Structures Interaction (CSI) Computer System (CCS)/Remote Interface Unit (RIU) is discussed. The CCS/RIU consists of a commercially available, Langley Research Center (LaRC) programmed, space flight qualified computer and a flight data acquisition and filtering computer, developed at LaRC. The tests were performed in the Space Structures Research Laboratory (SSRL) and included open loop excitation, closed loop control, safing, RIU digital filtering, and RIU stand alone testing with the CSI Evolutionary Model (CEM) Phase-0 testbed. The test results indicated that the CCS/RIU system is comparable to ground based systems in performing real-time control-structure experiments

Piezoelectric devices for vibration suppression: Modeling and application to a truss structure

For a space structure assembled from truss members, an effective way to control the structure may be to replace the regular truss elements by active members. The active members play the role of load carrying elements as well as actuators. A piezo strut, made of a stack of piezoceramics, may be an ideal active member to be integrated into a truss space structure. An electrically driven piezo strut generates a pair of forces, and is considered as a two-point actuator in contrast to a one-point actuator such as a thruster or a shaker. To achieve good structural vibration control, sensing signals compatible to the control actuators are desirable. A strain gage or a piezo film with proper signal conditioning to measure member strain or strain rate, respectively, are ideal control sensors for use with a piezo actuator. The Phase 0 CSI Evolutionary Model (CEM) at NASA Langley Research Center used cold air thrusters as actuators to control both rigid body motions and flexible body vibrations. For the Phase 1 and 2 CEM, it is proposed to use piezo struts to control the flexible modes and thrusters to control the rigid body modes. A tenbay truss structure with active piezo struts is built to study the modeling, controller designs, and experimental issues. In this paper, the tenbay structure with piezo active members is modelled using an energy method approach. Decentralized and centralized control schemes are designed and implemented, and preliminary analytical and experimental results are presented

Crew Exploration Vehicle Launch Abort Controller Performance Analysis

This paper covers the simulation and evaluation of a controller design for the Crew Module (CM) Launch Abort System (LAS), to measure its ability to meet the abort performance requirements. The controller used in this study is a hybrid design, including features developed by the Government and the Contractor. Testing is done using two separate 6-degree-of-freedom (DOF) computer simulation implementations of the LAS/CM throughout the ascent trajectory: 1) executing a series of abort simulations along a nominal trajectory for the nominal LAS/CM system; and 2) using a series of Monte Carlo runs with perturbed initial flight conditions and perturbed system parameters. The performance of the controller is evaluated against a set of criteria, which is based upon the current functional requirements of the LAS. Preliminary analysis indicates that the performance of the present controller meets (with the exception of a few cases) the evaluation criteria mentioned above

Aphids on Cruciferous Crops: Identification and Management

8 pp., 24 color photos, 6 illustrationsAt least five species of aphids attack cruciferous crops (cabbage, collards, cauliflower, broccoli, kale and others). This publication explains the characteristics that can help producers identify aphids and the damage they cause. Suggestions for scouting, management and control are included, along with an illustrated key to aphid identification

Electronic structure of NiS1−x_{1-x}Sex_x across the phase transition

We report very highly resolved photoemission spectra of NiS(1-x)Se(x) across the so-called metal-insulator transition as a function of temperature as well as composition. The present results convincingly demonstrate that the low temperature, antiferromagnetic phase is metallic, with a reduced density of states at E$_F$. This decrease is possibly due to the opening of gaps along specific directions in the Brillouin zone caused by the antiferromagnetic ordering.Comment: Revtex, 4 pages, 3 postscript figure

Bats of the Loess Hills Ecoregion of Southeast Nebraska

We surveyed bats at 49 sites in the Loess Hills Ecoregion of southeastern Nebraska, along the western edge of the eastern forest biome in eastern Richardson, Nemaha, and Otoe counties. We completed this study shortly before the northern long-eared bat (Myotis septentrionalis) was listed by the United States Fish and Wildlife Service under the Endangered Species Act. The expectation of listing, along with potential presence of the endangered Indiana bat (Myotis sodalis), motivated the study. We captured 183 bats of five species: eastern red bat (Lasiurus borealis) (n = 103; 56 %), big brown bat (Eptesicus fuscus) (n = 47; 26 %), evening bat (Nycticeius humeralis) (n = 27; 15 %), hoary bat (Lasiurus cinereus) (n = 4; 2 %), and northern long-eared bat (n = 2; 1 %). The mean catch per net site was 3.7 bats (SD = 4.8). The Eastern red bat was captured most commonly and at the most sites. We established the first record of this species from Nemaha County, with reproduction documented in all three counties. More reproductive female red bats were captured than adult males. Big brown bat captures consisted of approximately equal proportions adult males, reproductive females, and volant young of year. We established the first records for big brown bat reproduction in Otoe and Nemaha counties. Only reproductive female and juvenile evening bats were captured, with geographic and reproductive records established for all three counties. Captures of the hoary bat, a lactating female at one site and two juveniles at another, represented a Nemaha County geographic and reproductive record. We radio-tagged a non-reproductive female and an adult male northern long-eared bat from Otoe County and tracked them to roosts along the Missouri River, 3.43 and 2.03 km from the net site, respectively. We completed four emergence counts at each roost, with each bat exiting its respective roost on only one evening and neither bat visiting the other roost. We never documented more than three individuals exiting each roost on a given night. Overall, this study documented relatively low abundance, species richness, and species diversity when compared to studies in the eastern United States