Laser beamed power: Satellite demonstration applications

It is possible to use a ground-based laser to beam light to the solar arrays of orbiting satellites, to a level sufficient to provide all or some of the operating power required. Near-term applications of this technology for providing supplemental power to existing satellites are discussed. Two missions with significant commercial pay-off are supplementing solar power for radiation-degraded arrays and providing satellite power during eclipse for satellites with failed batteries

Development of ADOCS controllers and control laws. Volume 3: Simulation results and recommendations

The Advanced Cockpit Controls/Advanced Flight Control System (ACC/AFCS) study was conducted by the Boeing Vertol Company as part of the Army's Advanced Digital/Optical Control System (ADOCS) program. Specifically, the ACC/AFCS investigation was aimed at developing the flight control laws for the ADOCS demonstator aircraft which will provide satisfactory handling qualities for an attack helicopter mission. The three major elements of design considered are as follows: Pilot's integrated Side-Stick Controller (SSC) -- Number of axes controlled; force/displacement characteristics; ergonomic design. Stability and Control Augmentation System (SCAS)--Digital flight control laws for the various mission phases; SCAS mode switching logic. Pilot's Displays--For night/adverse weather conditions, the dynamics of the superimposed symbology presented to the pilot in a format similar to the Advanced Attack Helicopter (AAH) Pilot Night Vision System (PNVS) for each mission phase is a function of SCAS characteristics; display mode switching logic. Results of the five piloted simulations conducted at the Boeing Vertol and NASA-Ames simulation facilities are presented in Volume 3. Conclusions drawn from analysis of pilot rating data and commentary were used to formulate recommendations for the ADOCS demonstrator flight control system design. The ACC/AFCS simulation data also provide an extensive data base to aid the development of advanced flight control system design for future V/STOL aircraft

Environmental Audits and Incentive Compensation

This paper studies the link between environmental audits and employee compensation. The context is a one-period principal-agent relationship where the agent must allocate effort between financial and environmental tasks. The former are routinely monitored while the latter are audited (at some cost) only under specific circumstances. We find that the optimal wages have a lower mean and greater variance when there is an environmental audit than when there is not. This puts more risk on the agent, so the expected wage ex ante is higher and the agent's effort on the environmental task greater than in a situation with no environmental audits. Ce papier étudie le lien entre les audits environnementaux et la rémunération des employés. Dans un modèle d'agence à une période, l'agent doit partager son attention entre les aspects environnementaux et ceux strictement financiers de sa tâche. La performance de l'agent sur le plan financier est constamment surveillée; sur le plan environnemental, par contre, l'employeur n'effectue que des contrôles ponctuels au moyen d'audits environnementaux. On trouve que le salaire optimal a une moyenne inférieure et une variance supérieure quand l'employeur a recours à un audit environnemental. La menace d'un audit environnemental augmente donc le risque pesant sur l'agent, ce qui entraîne que le salaire attendu intialement par l'agent sera plus élevé et son attention aux aspects environnementaux plus forte que si cette menace n'existait pas.Environmental audits ; Employee compensation, Audits environnementaux ; Rémunération des employés

Development of ADOCS controllers and control laws. Volume 2: Literature review and preliminary analysis

The Advanced Cockpit Controls/Advanced Flight Control System (ACC/AFCS) study was conducted by the Boeing Vertol Company as part of the Army's Advanced Digital/Optical Control System (ADOCS) program. Specifically, the ACC/AFCS investigation was aimed at developing the flight control laws for the ADOCS demonstrator aircraft which will provide satisfactory handling qualities for an attack helicopter mission. The three major elements of design considered are as follows: Pilot's integrated Side-Stick Controller (SSC) -- Number of axes controlled; force/displacement characteristics; ergonomic design. Stability and Control Augmentation System (SCAS)--Digital flight control laws for the various mission phases; SCAS mode switching logic. Pilot's Displays--For night/adverse weather conditions, the dynamics of the superimposed symbology presented to the pilot in a format similar to the Advanced Attack Helicopter (AAH) Pilot Night Vision System (PNVS) for each mission phase as a function of ACAS characteristics; display mode switching logic. Findings from the literature review and the analysis and synthesis of desired control laws are reported in Volume 2. Conclusions drawn from pilot rating data and commentary were used to formulate recommendations for the ADOCS demonstrator flight control system design. The ACC/AFCS simulation data also provide an extensive data base to aid the development of advanced flight control system design for future V/STOL aircraft

An assessment of various side-stick controller/stability and control augmentation systems for night nap-of-Earth flight using piloted simulation

Several night nap-of-the-earth mission tasks were evaluated using a helmet-mounted display which provided a limited field-of-view image with superimposed flight control symbology. A wide range of stability and control augmentation designs was investigated. Variations in controller force-deflection characteristics and the number of axes controlled through an integrated side-stick controller were studied. In general, a small displacement controller is preferred over a stiffstick controller particularly for maneuvering flight. Higher levels of stability augmentation were required for IMC tasks to provide handling qualities comparable to those achieved for the same tasks conducted under simulated visual flight conditions

Environmental Auditing in Management Systems and Public Policy

New international standards for environmental auditing are now being actively promoted by public authorities and adopted by private firms. One important feature of these standards is their emphasis on managerial systems and incentives that support a wiser use of environmental resources. This paper studies such a system, in which incentive compensation may be based in part on the results of an environmental audit. It is found that optimal wages after an environmental audit is performed should have a greater range than wages paid when no audit has occured. It is also shown that the decision to conduct an environmental audit and the size of the expected wage in this case depend crucially on whether the agent's prudence (or precautionary motives) dominates or not his aversion to risk. It is finally found that the insertion of environmental audits within current management systems would certainly induce a manager to care more about the environment; moreover, although this may come at the expense of less concern for other activities, we find plausible circumstances in which properly designed environmental audits overcome such a tradeoff and increase the manager's attention to both environmental and traditional tasks. The public policy maker's role and interest in promoting environmental auditing standards is also discussed briefly. De nouvelles normes pour les audits environnementaux sont actuellement en train d'être élaborées et implantées par les gouvernements et les entreprises. Ces normes mettent principalement l'accent sur les systèmes de gestion et les incitations qui encouragent un meilleur usage des ressources environnementales. Cet article étudie un tel système, où la rémunération pourrait dépendre en partie des conclusions d'un audit environnemental. On trouve que le salaire versé après la tenue d'un audit devrait varier davantage que celui versé lorsqu'il n'y a pas eu d'audit. On montre aussi que la décision d'effectuer un audit environnemental et le niveau du salaire espéré dans ce cas dépendent essentiellement de la relation entre la prudence (ou la précaution) et l'aversion pour le risque du manager. On montre finalement que l'insertion d'audits environnementaux au sein des systèmes managériaux usuels poussera certainement un manager à se préoccuper davantage de l'environnement,0501s la redistribution de l'effort de ce dernier pourrait bien ne pas survenir au détriment de ses activités principales au sein de l'entreprise. On discute enfin brièvement du rôle et de l'intérêt du décideur public dans l'élaboration et la promotion de nouvelles normes pour les audits.Multi Task Principal Agent Analysis, Environmental Auditing, Risk Aversion, Prudence, Analyse principal-agent multi-tâches, Audits environnementaux, Aversion pour le risque, Prudence

Ecological Observations on Predatory Coccinellidae (Coleoptera) in Southwestern Michigan

Ecological observations on habitat utilization by thirteen species of predatory Coccinellidae were made at a southern Michigan site during 1989 and 1990. Most of species were common during both years and used both agricul- tural and uncultivated habitats. Coccinella septempunctata and Coleomegilla maculata, were the most abundant in agricultural crops (alfalfa, maize, soy- bean and triticale), whereas Adalia bipunctata and Cycloneda munda, were the most abundant in deciduous and bushy habitats

Modification of silicon carbide fibers for use in SiC/Ti composites

The degradation of silicon carbide fibers during exposure to conditions typical of composite fabrication was investigated. The tensile strength of pristine fibers and fibers sputtered with thin metal coatings were determined before and after treatment at 870 C for one hour in vacuum. Each fiber strength distribution was related by an analytical procedure to a projected composite ultimate tensile strength (PC UTS). The results indicate that a thin aluminum diffusion barrier can yield a 150 percent increase in PC UTS over the baseline SiC/Ti system

What proportion of adult allergy referrals to secondary care could be dealt with in primary care by a GP with special interest?

Background: The concept of a General Practitioner with Special Interest (GPwSI) was first proposed in the 2000 National Health Service Plan, as a way of providing specialised treatment closer to the patient’s home and reducing hospital waiting times. Given the patchy and inadequate provision of allergy services in the UK the introduction of GPwSIs might reduce the pressure on existing specialist services. Objectives: This study assessed what proportion of referrals to a specialist allergy clinic could be managed in a GPwSI allergy service with a predefined range of facilities and expertise (accurate diagnosis and management of allergy; skin prick testing; provision of advice on allergen avoidance; ability to assess suitability for desensitisation). Methods: 100 consecutive GP referrals to a hospital allergy clinic were reviewed to determine whether patients could be seen in a community-based clinic led by a general practitioner with special interest (GPwSI) allergy. The documentation relating to each referral was independently assessed by three allergy specialists. The referrals were judged initially on the referral letter alone and then re-assessed with the benefit of information summarised in the clinic letter, to determine whether appropriate triage decisions could be made prospectively. The proportion of referrals suitable for a GPwSI was calculated and their referral characteristics identified. Results: 29 % referrals were judged unanimously appropriate for management by a GPwSI and an additional 30 % by 2 of the 3 reviewers. 18 % referrals were unsuitable for a GPwSI service because of the complexity of the presenting problem, patient co-morbidity or the need for specialist knowledge or facilities. Conclusions and clinical relevance: At least a quarter, and possibly half, of allergy referrals to our hospital-based service could be dealt with in a GPwSI clinic, thereby diversifying the patient pathway, allowing specialist services to focus on more complex cases and reducing the waiting time for first appointments