Model-reference attitude control and reaction control jet engine placement for space shuttle

Analytical studies on the theoretical aspects of thrust vector control of large space vehicles were conducted. A system for attitude control of the space shuttle vehicle was developed. Major accomplishments of the project are: (1) investigation of a model-reference adaptive control scheme for controlling the space shuttle attitude and (2) determination of optimum placement of reaction control jet engines on space shuttles

Multivariable control theory applied to hierarchial attitude control for planetary spacecraft

Multivariable control theory is applied to the design of a hierarchial attitude control system for the CARD space vehicle. The system selected uses reaction control jets (RCJ) and control moment gyros (CMG). The RCJ system uses linear signal mixing and a no-fire region similar to that used on the Skylab program; the y-axis and z-axis systems which are coupled use a sum and difference feedback scheme. The CMG system uses the optimum steering law and the same feedback signals as the RCJ system. When both systems are active the design is such that the torques from each system are never in opposition. A state-space analysis was made of the CMG system to determine the general structure of the input matrices (steering law) and feedback matrices that will decouple the axes. It is shown that the optimum steering law and proportional-plus-rate feedback are special cases. A derivation of the disturbing torques on the space vehicle due to the motion of the on-board television camera is presented. A procedure for computing an upper bound on these torques (given the system parameters) is included

Oral History Interview: Mr. and Mrs. S. H. Boland

This interview is one of a series conducted concerning rural life in West Virginia. Mr. and Mrs. Boland have spent most of their lives in Summers County, West Virginia. Mrs. Boland\u27s parents died when she was young, and she and her two older sisters lived together on their farm until they married. Mr. and Mrs. Boland discuss their childhood experiences, education, courting practices, work experiences (Mr. Boland was Hinton fire chief for forty- seven years), the development of their rural district, and life in the country compared to city life.https://mds.marshall.edu/oral_history/1143/thumbnail.jp

Fulminant Clostridium difficile Enteritis after Proctocolectomy and Ileal Pouch-Anal Anastamosis

Clostridium difficile (C. difficile) infection of the small bowel is very rare. The disease course is more severe than that of C. difficile colitis, and the mortality is high. We present a case of C. difficile enteritis in a patient with ileal pouch-anal anastamosis (IPAA), and review previous case reports in order to better characterize this unusual condition

Predictors and trajectory of performance status in patients with advanced cancer: A secondary data analysis of the international European Palliative Care Cancer Symptom study.

Background: Performance status, a predictor of cancer survival, and ability to maintain independent living deteriorate in advanced disease. Understanding predictors of performance status trajectory could help identify those at risk of functional deterioration, target support for independent living and reduce service costs. The relationship between symptoms, analgesics and performance status is poorly delineated. Aim: The aim of this study is to determine whether demographics, analgesics, disease characteristics, quality-of-life domains and C-reactive protein predict the trajectory of Karnofsky Performance Status (KPS) in patients with advanced cancer. Design: The study design is the secondary data analysis of the international prospective, longitudinal European Palliative Care Cancer Symptom study (ClinicalTrials.gov: NCT01362816). A multivariable regression model was built for KPS area under the curve per day (AUC). Setting and participants: This included adults with advanced, incurable cancer receiving palliative care, without severe cognitive impairment and who were not imminently dying (n = 1739). Results: The mean daily KPS AUC (n = 1052) was 41.1 (standard deviation = 14.1). Opioids (p < 0.001), co-analgesics (p = 0.023), poorer physical functioning (p < 0.001) and appetite loss (p = 0.009) at baseline were explanatory factors for lower KPS AUC. A subgroup analysis of participants with C-reactive protein data (n = 240) showed that only C-reactive protein (p = 0.040) and physical function (p < 0.001) were associated with lower KPS AUC. Conclusion: This study is novel in determining explanatory factors for subsequent functional trajectories in an international dataset and identifying systemic inflammation as a candidate therapeutic target to improve functional performance. The effect of interventions targeting physical function, appetite and inflammation, such as those used for cachexia management, on maintaining functional status in patients with advanced cancer needs to be investigated

A General Simulator Using State Estimation for a Space Tug Navigation System

A general simulation program is presented (GSP) involving nonlinear state estimation for space vehicle flight navigation systems. A complete explanation of the iterative guidance mode guidance law, derivation of the dynamics, coordinate frames, and state estimation routines are given so as to fully clarify the assumptions and approximations involved so that simulation results can be placed in their proper perspective. A complete set of computer acronyms and their definitions as well as explanations of the subroutines used in the GSP simulator are included. To facilitate input/output, a complete set of compatable numbers, with units, are included to aid in data development. Format specifications, output data phrase meanings and purposes, and computer card data input are clearly spelled out. A large number of simulation and analytical studies were used to determine the validity of the simulator itself as well as various data runs

Some optimal considerations in attitude control systems

The conventional six-engine reaction control jet relay attitude control law with deadband is shown to be a good linear approximation to a weighted time-fuel optimal control law. Techniques for evaluating the value of the relative weighting between time and fuel for a particular relay control law is studied along with techniques to interrelate other parameters for the two control laws. Vehicle attitude control laws employing control moment gyros are then investigated. Steering laws obtained from the expression for the reaction torque of the gyro configuration are compared to a total optimal attitude control law that is derived from optimal linear regulator theory. This total optimal attitude control law has computational disadvantages in the solving of the matrix Riccati equation. Several computational algorithms for solving the matrix Riccati equation are investigated with respect to accuracy, computational storage requirements, and computational speed

Der Anbau von Linsen und Erbsen im Gemenge

In Germany, lentils (Lens culinaris) are traditionally grown in mixture with cereals to reduce lodging and weed pressure. To test semi-leafless pea (Pisum sativum) as an alternative companion crop instead of dwarf oat (Avena sativa), a field trial was conducted in 2015 at the organic research station of the University of Hohenheim, south-west Germany. The three crops were cultivated in pure stands and in ratios of 1:3, 1:1 and 3:1 (lentil : pea or oat). Focus was on comparing lodging resistance, weed suppression, and grain yield. Lodging was low in all mixtures but high in lentil pure stands. Yields were very high for lentils and peas but rather low for oats (3.2 t ha-1, 4.9 t ha-1, and 3.2 t ha-1, in pure stands). Similarly, high lentil yields were achieved in the mixtures lentil-pea 3:1 (3.0 t ha-1), lentil-oat 3:1 (2.9 t ha-1), and lentil-oat 1:1 (2.7 t ha-1). Compared with pure stands, land use efficiency was up to 20 % higher in lentil-pea mixtures and up to 33 % higher in lentil-oat mixtures. When compared with lentil pure stands, weed biomass was up to 26 % (lentil-pea 1:3) lower in mixtures with pea and up to 61 % (lentil-oat 1:1) lower in mixtures with oat. Overall, semi-leafless pea is a good alternative to dwarf oat as a companion crop for lentils