Reynolds and Mach number simulation of Apollo and Gemini re-entry and comparison with flight

Reynolds and Mach numbers simulation of Apollo and Gemini reentry compared with flight dat

Hydrodynamics of Suspensions of Passive and Active Rigid Particles: A Rigid Multiblob Approach

We develop a rigid multiblob method for numerically solving the mobility problem for suspensions of passive and active rigid particles of complex shape in Stokes flow in unconfined, partially confined, and fully confined geometries. As in a number of existing methods, we discretize rigid bodies using a collection of minimally-resolved spherical blobs constrained to move as a rigid body, to arrive at a potentially large linear system of equations for the unknown Lagrange multipliers and rigid-body motions. Here we develop a block-diagonal preconditioner for this linear system and show that a standard Krylov solver converges in a modest number of iterations that is essentially independent of the number of particles. For unbounded suspensions and suspensions sedimented against a single no-slip boundary, we rely on existing analytical expressions for the Rotne-Prager tensor combined with a fast multipole method or a direct summation on a Graphical Processing Unit to obtain an simple yet efficient and scalable implementation. For fully confined domains, such as periodic suspensions or suspensions confined in slit and square channels, we extend a recently-developed rigid-body immersed boundary method to suspensions of freely-moving passive or active rigid particles at zero Reynolds number. We demonstrate that the iterative solver for the coupled fluid and rigid body equations converges in a bounded number of iterations regardless of the system size. We optimize a number of parameters in the iterative solvers and apply our method to a variety of benchmark problems to carefully assess the accuracy of the rigid multiblob approach as a function of the resolution. We also model the dynamics of colloidal particles studied in recent experiments, such as passive boomerangs in a slit channel, as well as a pair of non-Brownian active nanorods sedimented against a wall.Comment: Under revision in CAMCOS, Nov 201

Building top management muscle in a slow growth environment: How different is better at Greyhound Financial Corporation

The turbulence experienced in the 1980s in the U.S. business environment has led to something of a motivational crisis among corporate managers. Increased competition, budget constraints, and changing demographics are forcing companies into adopting strategies geared toward downsizing and flatter organizational structures. While corporate America probably has begun to accept its leaner profile, it has not yet successfully addressed the issue of how to keep the best managerial talent tuned in and turned on in an era of dwindling resources. This article describes and assesses one corporation\u27s efforts to maintain top-managerial motivation through a unique form of job swapping called the Muscle Building program at Greyhound Financial Corporation in Phoenix, Arizona. Muscle building. a top-management job rotation program, helps prevent career gridlock, fosters management diversity, and provides for top-management succession. Hidden costs and benefits of the program and issues concerning its implementation are discussed

An Analysis of the Economic Factors and Changes in Land-Use Associated with the Transition to a Beef Feedlot System in Waterloo County

The first objective of this study is to examine the transition from the traditional system of agriculture to a relatively new type of operation, the beef feedlot enterprise. This will incldue not only an examination of the actual transition but also the factors which were conducive to such a change. In this respect, the current, as well as the past position of beef in the agricultural economy, will be discussed as a contributing factor to the movement toward specialization. The views and attitudes of the framers in the study group concerning their change in vocation will also be examined and evaluated as an important indicator concerning the relative success of the beef feedlot venture. The second objective is to analyze the economics of the operations of a selected group of feedlot operations who are located in Waterloo County and who, recently, initiated the modification of their existing farm facilities to feedlot requirements. The economic situation of a system in transition is of major concern in determining the viability of the operation. The analysis will basically include a discussion and comparison of various resources common to a feedlot operation and the relative efficiency with which these resources are used by the study group memebrs. Here also, an indication will be given concernign the possible effect that the size of operation has on the use made of the resources contributing to the overall success of the operation. The third objective of the study is to provide for the reader some factual information on the beef feedlot system and to better acquaint the reader with this type of operation. This will involve a consideration of various methods of livestock production within the feedlot as well as an overview of some of teh characteristics and functions of a beef feedlot operation

Borgs in the Org? Organizational Decision Making and Technology

Data warehousing and the development of the World Wide Web both augment information gathering (search) processes in individual decision making by increasing the availability of required information. Imagine, for example, that one wanted to buy new golf clubs. Thirty years ago, the cost of information gathering would likely have limited an individual\u27s search process to geographically proximal vendors and the golf clubs they stocked. Today, a prospective purchaser can log onto the World Wide Web to find out what types of golf clubs are available anywhere; consult databases, chat rooms, and bulletin boards (e.g., epinions.com) to gather product information and user opinions; and compare prices across vendors around the world

Lawyers and the Atonement

This BYU–Hawaii Presidential Lecture was given in Laie, Hawaii on March 23, 2000

Joint Tenancy and Community Property

The public demand in Washington which led to the adoption of the joint tenancy initiative is not surprising in view of the widespread use of this form of title in other states. However, Washington is still a community property state and the people\u27s desire for joint tenancy with its popular survivorship feature does not necessarily indicate their intention to change the community property system. Laymen will commonly use community funds to buy property and will now take title in joint tenancy, fully hoping to have some of the advantages of each. This practice has led to a deluge of litigation in California and some in other states, and will undoubtedly give rise to problems in Washington. Laymen usually select the joint tenancy form of title because of its survivorship feature, with no thought given to tax consequences or problems rising on severance or divorce or even to the matter of treating creditors and other beneficiaries fairly. Taking title to property in both names has a strong emotional or psychological appeal. People do not realize that except for very small no tax situations the work of the lawyer and the resulting expense is just as great if property is in joint tenancy as if it is in some other form. Before examining the problems surrounding the interrelation of community property and joint tenancy, it is first necessary to examine a few of the more important joint tenancy characteristics and contrast them with community property rules