2,582 research outputs found
Variable response load limiting device
An energy absorbing device used as a load limiting member in a structure to control its response to applied loads is described. It functions by utilizing a spool assembly having flanged ends and an interior cavity of sufficiently large diameter to cause it to deform plastically at a prescribed load. In application, the spool is utilized as a pivot point for the legs of an airplane seat. When properly designed and integrated into the seat arrangement the spool will twist about its axis, deforming plastically when the impact load exceeds the spool yield value. Through this deformation, the spool absorbs the kinetic energy of the movement of the seat at a substantially constant rate, thereby controlling the level of loads transmitted to the seat occupant. By proper sizing and collection of materials, it is possible to control load response in a predictable manner
Ion beam surface modification
The essential details of a study on the practical applications and mechanisms of polymer sputtering via Argon ion impact are summarized. The potential to modify the properties of polymer surfaces to improve their adherence, durability, biocompatibility, or other desirable properties by ion beam sputtering was emphasized. Ion beam milling can be of benefit as an analytical tool to obtain composition versus depth information. Ion impact from a directed ion gun source specifically etches polymer structures according to their morphologies, therefore this technique may be useful to study unknown or new morphological features. Factors addressed were related to: (1) the texture that arises on a polymer target after ion impact; (2) the chemistry of the top surface after ion impact; (3) the chemistry of sputtered films of polymeric material deposited on substrates placed adjacent to targets during ion impact; and (4) practical properties of textured polymer targets, specifically the wettability and adhesive bonding properties
A Builder's Guide to Water and Energy
The work on which this report is based was supported in part by funds provided by the Office of Water
Research and Technology (Project A-Q65-ALAS), US. Department of the interior, Washington, D.C., as
authorized by the Water Research and Development Act of 1978
Effect of polymer properties and adherend surfaces on adhesion
High temperature polymer surface characteristics associated with joint strength were evaluated. Selected samples represented composite adherends, aluminum filler and fiber glass carrier cloth. Detailed analysis of fractured joint surfaces revealed unique characteristics typical of the specific adhesive formulations and test conditions. A fracture mechanism model was developed for correlating macroscopic shear strength and microstructure of fracture surfaces. Applications were made to unpublished data on polyimides and fluoropolymers
A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics
The effects of composites as adherends was studied. Several other variables were studied by fractography: aluminum powder adhesive filler, fiber glass cloth scrim or adhesive carrier, new adhesives PPQ-413 and LARC-13, and strength-test temperature. When the new results were juxtaposed with previous work, it appeared that complex interactions between adhesive, adherend, bonding, and testing conditions govern the observed strength and fracture-surface features. The design parameters likely to have a significant effect upon strength-test results are listed
HEDGING SPOT CORN: AN EXAMINATION OF THE MINNEAPOLIS GRAIN EXCHANGE'S CASH SETTLED CORN CONTRACT
This research examines the potential basis behavior and hedging effectiveness for the Minneapolis Grain Exchange's (MGE) cash settled corn contract. MGE futures cash settle to the National Corn Index (NCI) calculated by Data Transmission Network (DTN). Focusing on seven regions in Illinois, the data suggest that NCI Futures offer potential advantages over the existing Chicago Board of Trade (CBOT) corn futures. In particular, nearby basis variability could be reduced by nearly one-half from 8.8 cents per bushel to 4.5 cents per bushel, and hedging effectiveness may increase from an average of 80% for the CBOT to 93% for the NCI.Crop Production/Industries, Marketing,
What Are Kinship Terminologies, and Why Do We Care? A Computational Approach to Analyzing Symbolic Domains
Kinship is a fundamental feature and basis of human societies. We describe a set of computational tools and services, the Kinship Algebra Modeler, and the logic that underlies these. These were developed to improve how we understand both the fundamental facts of kinship, and how people use kinship as a resource in their lives. Mathematical formalism applied to cultural concepts is more than an exercise in model building, as it provides a way to represent and explore logical consistency and implications. The logic underlying kinship is explored here through the kin term computations made by users of a terminology when computing the kinship relation one person has to another by referring to a third person for whom each has a kin term relationship. Kinship Algebra Modeler provides a set of tools, services and an architecture to explore kinship terminologies and their properties in an accessible manner
Management Succession in a Two-Family-Owned Business: A Case Study
The purpose of this paper was to examine the impact in a two-family-owned business of the management succession process to the second generation. The research explored the use and makeup of a management team in transferring the leadership of the company. The study looked at the preparation and determination of which members of the family would assume positions formerly held by the two patriarchs and who would assume executive responsibilities as president. The research endeavored to answer the following question: How is succession planning for multiple senior executive positions in a two-family-owned business accomplished in a second-generation family-executive team? The research study used case study methodology to look at a business located in Southern California. The case study focused on the two patriarchs of the business and the nine members of the executive management team. The findings of this research contributes to the body of information on management succession in a family-owned business and the importance of using a management team to facilitate the process of transferring leadership to the next generation
Geology of the Scaly Mountain quadrangle, emphasizing the structures, timing and emplacement mechanisms for the Rabun Granodiorites, eastern Blue Ridge, southwestern North Carolina
This thesis examines the geology of the Scaly Mountain quadrangle in the eastern Blue Ridge of southwestern North Carolina. Particular emphasis was placed on determining the structure, timing, and emplacement mechanisms of the Rabun granodiorite pluton. The Scaly Mountain quadrangle was mapped in detail (1:12,000 scale). The mapping effort included collection of structural data from 1,333 data stations using a Brunton compass. Particular attention was paid to structural measurements that were taken within the Rabun pluton, including measurements of what are interpreted to be both magmatic flow foliations and tectonic foliations (two distinct foliations); folds, and the orientations of the folds and other linear structures; faults along the edge of the pluton in some areas; fractures; contacts with the surrounding country rock; and crosscutting dikes in the area. After the mapping was completed, the structural data were compiled at 1:24,000 scale and analyzed to determine deformation events, average orientations of folds and other linear structures, interrelationships of the tectonic units, an^ perhaps most importantly for this study, different fabric relationships that will provide clues about the emplacement history of the Rabun granodiorite. Conclusions drawn from this study are: (1) The Scaly Mountain quadrangle contains three tectonic units: the Chattahoochee thrust sheet, the Dahlonega gold belt, and the Shope Fork thrust sheet. (2) The rocks present in the Sealy Mountain quadrangle are: the Tallulah Falls Formation (graywacke-schist member), the Rabun granodiorite, the Otto Formation, the Coweeta Group (Coleman River Formation), calc-silicate rocks, amphibolites, and pegmatites. In addition there are surficial deposits of colluvium, alluvium, and ancient landslides. (3) There are six to seven deformation events represented in the rocks in the Scaly Mountain quadrangle. (4) Evidence for multiple deformation events can be seen along the trace of the Chattahoochee fault. The fault deforms the Rabun granodiorite, truncates structures in the surrounding country rock, and is itself folded. Evidence for multiple deformation events can also be seen in the surrounding country rock. There is an early foliation that is preserved in boudins. There are at least two generations of folding as well. (5) The Chattahoochee fault postdates the Rabun granodiorite. Evidence for this is the truncation of the Rabun pluton by the Chattahoochee fault. (6) The Rabun granodiorite consists of a medium-grained phase and a megacrystic phase. (7) The Rabun granodiorite contains a magmatic flow foliation and an overprinting tectonic foliation. (8) The Rabun granodiorite was emplaced by a combination of mechanisms either operating together or at different times during the pluton emplacement. These are: stoping, diapirism, outward displacement of the Earth\u27s surface, the principle of effective stress, and dike-feeding of the pluton
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