Hexagonal spiral growth in the absence of a substrate

Experiments on the formation of spiraling hexagons (350 - 1000 nm in width) from a solution of nanoparticles are presented. Transmission electron microscopy images of the reaction products of chemically synthesized cadmium nanocrystals indicate that the birth of the hexagons proceeds without assistance from static screw or edge dislocatons, that is, they spiral without constraints provided by an underlying substrate. Instead, the apparent growth mechanism relies on what we believe is a dynamical dislocation identified as a dense aggregate of small nanocrystals that straddles the spiraling hexagon at the crystal surface. This nanocrystal bundle, which we term the "feeder", also appears to release nanocrystals into the spiral during the growth process.Comment: 4 pages, 5 figure

Recruiting Older Workers: Realities and Needs of the Future Workforce

This chapter examines literature pertaining to the recruitment of older workers. It begins by addressing the question of relevance and why older worker recruitment matters. It then examines what is known about older workers, including their attitudes, motivations, and behaviors. Next the chapter addresses what employers are looking for in older workers and, more specifically, discusses the continuum of employers’ practices from those that aggressively try to attract and retain older workers and apply a conservation model of older worker management to those that apply a depreciation model and focus primarily on retrenchment and downsizing older employees. Finally, it addresses how employers can recruit older workers through changes in organizational policies and practices

Aging, Retirement and Human Resources Management: A Strategic Approach

This chapter introduces the organizational view of retirement by exploring the relationship between organizational strategy and human resource management decisions regarding retirement. The authors begin with an overview of organizational strategy and discuss two methods used to plan for an aging and retiring workforce. Several key human resource decisions related to retirement are then addressed. In the pre-retirement phase, the role of HR In helping employees to prepare for retirement Is discussed, focusing primarily on financial planning and other retirement-related benefits. Next, human resource decisions pertaining to managing a retirement-ready workforce are discussed, addressing specifically the issues of knowledge transfer and motivating performance. Finally, interactions with individuals after retirement are discussed by looking at recruitment and bridge employment

Putting off Tomorrow to Do What You Want Today: Planning for Retirement

In this article we note that in the coming years, a larger number of people will be experiencing retirement for a longer period of time than ever before and that despite this fact, many will find themselves unprepared for this stage of their lives. We review the literature on retirement preparation, structuring our review around the key questions that need to be addressed when planning for retirement: (a) What will I do? (b) How will I afford it? (c) Where will I live? and (d) Who will I share it with? We make a number of suggestions for research and practice. We conclude that although psychology has begun to play a role in understanding and addressing retirement preparation, there are considerable opportunities for psychologists to engage with this issue in their research and applied work

STACBEAM 2

An investigation being conducted by Astro Aerospace Corporation (Astro) for Jet Propulsion Laboratory in which efficient structures for geosynchronous spacecraft solar arrays are being developed is discussed. Recent developments in solar blanket technology, including the introduction of ultrathin (50 micrometer) silicon solar cells with conversion efficiencies approaching 15 percent, have resulted in a significant increase in blanket specific power. System specific power depends not only on blanket mass but also on the masses of the support structure and deployment mechanism. These masses must clearly be reduced, not only to minimize launch weight, but also to increase array natural frequency. The solar array system natural frequency should be kept high in order to reduce the demands on the attitude control system. This goal is approached by decreasing system mass, by increasing structural stiffness, and by partitioning the blanket. As a result of this work, a highly efficient structure for deploying a solar array was developed

Polydimethylsiloxane based microfluidic diode

In this paper, we present a novel elastomer-based microfluidic device for rectifying flow. The device is analogous to an electronic diode in function since it allows flow in one direction and stops flow in the opposing direction. The device is planar, in-line and can be replica molded via standard soft lithography techniques. The fabrication process is outlined in detail and follows a simple procedure that requires only photolithography and one replica molding step. Several geometries of devices are presented along with their flow versus pressure characteristics. A brief discussion of the device behavior is presented along with possible uses for the device

Stencils and problem partitionings: Their influence on the performance of multiple processor systems

Given a discretization stencil, partitioning the problem domain is an important first step for the efficient solution of partial differential equations on multiple processor systems. Partitions are derived that minimize interprocessor communication when the number of processors is known a priori and each domain partition is assigned to a different processor. This partitioning technique uses the stencil structure to select appropriate partition shapes. For square problem domains, it is shown that non-standard partitions (e.g., hexagons) are frequently preferable to the standard square partitions for a variety of commonly used stencils. This investigation is concluded with a formalization of the relationship between partition shape, stencil structure, and architecture, allowing selection of optimal partitions for a variety of parallel systems