Investigations of simulated aircraft flight through thunderstorm outflows

The effects of wind shear on aircraft flying through thunderstorm gust fronts were investigated. A computer program was developed to solve the two dimensional, nonlinear equations of aircraft motion, including wind shear. The procedure described and documented accounts for spatial and temporal variations of the aircraft within the flow regime. Analysis of flight paths and control inputs necessary to maintain specified trajectories for aircraft having characteristics of DC-8, B-747, augmentor wing STOL, and DHC-6 aircraft was recorded. From the analysis an attempt was made to find criteria for reduction of the hazards associated with landing through thunderstorm gust fronts

Pilot-aircraft system reponse to wind shear

The nonlinear aircraft motion and automatic control model is expanded to incorporate the human pilot into simulations of aircraft response to wind to wind shear. The human pilot is described by a constant gains lag filter. Two runs are carried out using pilot transfer functions. Fixed-stick, autopilot, and manned computer simulations are made with an aircraft having characteristics of a small commuter type aircraft flown through longitudinal winds measured by a Doppler radar beamed along the glide slope. Simulations are also made flying an aircraft through sinusoidal head wind and tail wind shears at the phugoid frequency to evaluate the response of manned aircraft in thunderstorm wind environments

Current research on aviation weather (bibliography), 1979

The titles, managers, supporting organizations, performing organizations, investigators and objectives of 127 current research projects in advanced meteorological instruments, forecasting, icing, lightning, visibility, low level wind shear, storm hazards/severe storms, and turbulence are tabulated and cross-referenced. A list of pertinent reference material produced through the above tabulated research activities is given. The acquired information is assembled in bibliography form to provide a readily available source of information in the area of aviation meteorology

Engineering handbook on the atmospheric environmental guidelines for use in wind turbine generator development

The guidelines are given in the form of design criteria relative to wind speed, wind shear, turbulence, wind direction, ice and snow loading, and other climatological parameters which include rain, hail, thermal effects, abrasive and corrosive effects, and humidity. This report is a presentation of design criteria in an engineering format which can be directly input to wind turbine generator design computations. Guidelines are also provided for developing specialized wind turbine generators or for designing wind turbine generators which are to be used in a special region of the United States

Feasibility study of a procedure to detect and warn of low level wind shear

A Doppler radar system which provides an aircraft with advanced warning of longitudinal wind shear is described. This system uses a Doppler radar beamed along the glide slope linked with an on line microprocessor containing a two dimensional, three degree of freedom model of the motion of an aircraft including pilot/autopilot control. The Doppler measured longitudinal glide slope winds are entered into the aircraft motion model, and a simulated controlled aircraft trajectory is calculated. Several flight path deterioration parameters are calculated from the computed aircraft trajectory information. The aircraft trajectory program, pilot control models, and the flight path deterioration parameters are discussed. The performance of the computer model and a test pilot in a flight simulator through longitudinal and vertical wind fields characteristic of a thunderstorm wind field are compared

Managers\u27 Fiduciary Duties in Financially Distressed Corporations: Chaos in Delaware (and Elsewhere)

In this article, the authors consider the nature of corporate managers’ fiduciary duties in periods when the company is in financial distress. This matter is important not only to corporate managers, who need clear rules regarding their duties, but also to equity and debt investors, who must understand the nature of corporate fiduciary duties in order to price the capital that they contribute to the enterprise and allocate the financial risks of loss to the most efficient risk bearer from among the investors. Unfortunately, courts – especially the important Delaware courts – have made a mess of all of this. In the positive portion of the article, the authors describe and offer some clarification of corporate managers’ shifting fiduciary duties, as the corporation’s financial distress deepens. They conclude that corporate managers are obligated in periods when the corporation is solvent to act in the best interests of shareholders. When, however, the corporation moves into the “vicinity of insolvency”, corporate managers are obliged to act in the best interests of some undefined conglomerate of corporate stakeholders. In actual insolvency managers’ duties shift to a duty to act in the best interests of creditors. Finally, in bankruptcy, corporate managers must act in the best interests of shareholders and creditors as a whole. The authors find these poorly articulated and constantly shifting standards to be pernicious, both with regard to the ability of corporate managers to make legally proper decisions and with regard to investors’ ability to price their investments and predictably and efficiently allocate their risks of loss. In the normative portion of the article, the authors argue for an abandonment of this confusing and inefficient regime of corporate fiduciary duties. Their view is that in all periods prior to bankruptcy, the fiduciary duties of corporate managers should be consistently defined by reference to the best interests of shareholders. Once a company is in bankruptcy, they believe that the obligation of managers should shift to an obligation to act in the best interests of shareholders and creditors as a whole. This approach will, in their view, lead in most (but not necessarily all) cases to pleasing and efficient outcomes. It will provide intelligible criteria to guide the actions of managers and will enable investors to price their capital and allocate risks of loss in efficient manners

Managers’ Fiduciary Duties in Financially Distressed Corporations: Chaos in Delaware (and Elsewhere)

The inherent conflict between creditors and shareholders has long occupied courts and commentators interested in corporate governance. Creditors holding fixed claims to the corporation\u27s assets generally prefer corporate decision making that minimizes the risk of firm failure. Shareholders, in contrast, have a greater appetite for risk, because, as residual owners, they reap the rewards of firm success while sharing the risk of loss with creditors. Traditionally, this conflict is mediated by a governance structure that imposes a fiduciary duty on the corporation\u27s managers-its officers and directors-to maximize the value of the shareholders\u27 interests in the firm. In this traditional view, officers, and directors serve as agents of the shareholders and thus are charged with a fiduciary duty to maximize the value of the principals\u27 ownership interests. Under this model of corporate governance, managers are not agents for the company\u27s creditors and thus owe no fiduciary duty to act in the best interests of creditors. For the most part, this traditional model of corporate governance has dominated corporate law. Over recent years, however, a number of courts have suggested or held that these normal fiduciary duties of corporate managers may change when firms move into and through periods of deepening financial distress. The purpose of this Article is twofold. First, we offer a positive analysis of the fiduciary duties of managers, as corporations move along the time spectrum from solvency to Chapter 11 reorganization. While, certainly, we are unable to clarify entirely the mess that courts have created, we believe that we are able to offer guidance regarding the present state of the law and how the law is likely to evolve on these important matters. In the second part of the Article, we offer our prescription for corporate managers’ fiduciary duties, as corporations move along the time spectrum from solvency to bankruptcy. Our view is that the fiduciary obligation of corporate managers should be uniform across the pre-bankruptcy period, changing only at the point the company enters into Chapter 11. Our prescription is informed by simple economic concepts. Our view is that clear and efficient default rules are of the utmost importance, since such rules will protect the expectations of the parties, respect their pricing, and thus facilitate an efficient allocation of the risk of loss in financial transactions

A Quarter Century, Not a Raised Voice

A tribute to Professor Willburt “Burt” D. Ham

Explicitly correlated trial wave functions in Quantum Monte Carlo calculations of excited states of Be and Be-

We present a new form of explicitly correlated wave function whose parameters are mainly linear, to circumvent the problem of the optimization of a large number of non-linear parameters usually encountered with basis sets of explicitly correlated wave functions. With this trial wave function we succeeded in minimizing the energy instead of the variance of the local energy, as is more common in quantum Monte Carlo methods. We applied this wave function to the calculation of the energies of Be 3P (1s22p2) and Be- 4So (1s22p3) by variational and diffusion Monte Carlo methods. The results compare favorably with those obtained by different types of explicitly correlated trial wave functions already described in the literature. The energies obtained are improved with respect to the best variational ones found in literature, and within one standard deviation from the estimated non-relativistic limitsComment: 19 pages, no figures, submitted to J. Phys.