3,826 research outputs found
Rapid data comparison technique development for N-ray/X-ray analysis
An operational N-ray/X-ray computer analysis system for nondestructive testing problems was realized by developing: (1) more efficient data transfer routines for use in existing image processing systems; (2) the capability to store and analyze multiple N-ray/X-ray images; (3) an efficient 2-D Fast Fourier Transform; and (4) transfer functions compensation capability to correct for distortions and nonlinearities of N-rays/X-rays. Applications of the technique are summarized for the following: thermal protection system tile with hydraulic fluid; thermal protection system tile with corrosion; thermal protection system tile debonding; stainless steel tubing corrosion; defective electrical devices; fast film restoration and deblur; corrosion tracking over time; reduction of source vignetting, and identification of materials (0 rings, Teflon parts, soft goods) via table look up
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Replication of mixing achieved in large co-rotating screw extruder using a novel laboratory 10-100g minimixer
YesWhen compounding polymers with additives to develop materials at specifications (colouring plastics is the simplest example), the difficulties is in getting the formulation right the first time. Also, when developing completely new materials such as in nanotechnology applications, there is a need to do the initial trials safely and with as small quantities as possible to enable a wide range of experimentation. Wiith traditional applications, often the initial compounding formulation is done using small single or twin screw extruders but with machines that have a fair output to instruct the large scale operation. This step is costly in material wastage and time but more importantly it often does not provide the right formulation which in turn results in bigger wastage cost at the industrial scale before the right formulation is eventually obtained. With the very new material formulations, any reduction in cost of development is always essential. With these aims in mind, we have developed a new minimixer capable of handling tiny quantities of order 10-100g but the minimixer is capable of reproducing the very high mixing conditions experienced in large machines. This invention provides a new opportunity to develop new products quickly, safely and cheaply. The application is not restricted to polymers and can be extended to other soft materials. It has also other spin-offs as a research tool for studying mixing and developing new, more efficient, mixing flows. In this paper we explain the principle of operation we have engineered to produce such intense mixing. Basically, the device is based on combining two opposing flows: a single screw extruder circulation flow with a twin screw extruder mixing flow. The mixing is carried out as a batch but on its completion, the single screw extruder flow is reversed and becomes co-current with the twin extruder flow to enable the discharging of the batch through a die. In the paper we present mixing data obtained with various polymer-additive combinations tested in the minimixer under various conditions of screw speeds, mixing times and temperatures and at the larger scale to underpin the operation of this novel mixer. The quality of mixing of the extrudate was measured using a variety of methods depending on applications: using image analysis of microtome sections of the extrudate or of blown film samples produced from the formulations or measuring electrical properties
Language-universal constraints on the segmentation of English
Two word-spotting experiments are reported that examine whether the Possible-Word Constraint (PWC) [1] is a language-specific or language-universal strategy for the segmentation of continuous speech. The PWC disfavours parses which leave an impossible residue between the end of a candidate word and a known boundary. The experiments examined cases where the residue was either a CV syllable with a lax vowel, or a CVC syllable with a schwa. Although neither syllable context is a possible word in English, word-spotting in both contexts was easier than with a context consisting of a single consonant. The PWC appears to be language-universal rather than language-specific
Redemption from Darkness: A Study of Form and Function, Sacred and Secular, within the Genre of Apocalypse
The genre of apocalypse has an irresistible draw. The concepts of beginning and end to humankind as well as the cosmos situate themselves in our daily stories, microcosmic narratives that repeat through time, placing the footprint of humankind a little more firmly into the earth, a place we have called our home from beginning and, naturally, to the end. In a world that constantly pushes forward to the next piece of technological equipment, reducing mass pandemics to mere over the counter solutions, and extending its hand into the abyss of the unknown universe, humanity craves the elusive next chapter in the novel of the world.
But what is to be attained when we reach the climax? When we are situated in the denouement? And finally, what happens when all is at an end? There is a universal truth of birth, and a universal truth of death (despite our advances to elude it). By that logic there must exist a macrocosmic version, a global scale birth, termed creation by many, and thus a large scale death.
But since death of the individual remains a complete mystery, many diverse factions exist. This extends to the global picture then, not only seeking inquiry into what happens after we (as in the individual) but when the entire world ceases to exist.
This thesis is an attempt to explore the genre of apocalypse for a deeper understanding of these questions and notions. With various systems in place, such as those put forth by John J. Collins and other apocalypse scholars, there exists a possibility to examine various iterations of apocalypses. By examining paradigm traits and tiers and the complications that arise with systemization, this thesis develops a methodology in which to include the functional take on various case studies of apocalypse. Generally reserved for examinations of sacred text, the expanded methodology presented here will seek to not only look at an example of said text, but also a secular text, two examples of ‘sacred function’, and one ideological example of a secular function. This study is not about changing the makeup of the paradigm, nor is it an effort to disprove criteria, nor tack on additional items. The goal is to use the paradigm to identify a more well-rounded view of the genre, and then see what can be gleaned from those categories and their prototypes. In doing so, the definition of the apocalypse genre will be more comprehensive, and thus beneficial for any avenue of study to which it is applied
Technology evaluation of man-rated acceleration test equipment for vestibular research
The considerations for eliminating acceleration noise cues in horizontal, linear, cyclic-motion sleds intended for both ground and shuttle-flight applications are addressed. the principal concerns are the acceleration transients associated with change in direction-of-motion for the carriage. The study presents a design limit for acceleration cues or transients based upon published measurements for thresholds of human perception to linear cyclic motion. The sources and levels for motion transients are presented based upon measurements obtained from existing sled systems. The approaches to a noise-free system recommends the use of air bearings for the carriage support and moving-coil linear induction motors operating at low frequency as the drive system. Metal belts running on air bearing pulleys provide an alternate approach to the driving system. The appendix presents a discussion of alternate testing techniques intended to provide preliminary type data by means of pendulums, linear motion devices and commercial air bearing tables
SWECS tower dynamics analysis methods and results
Several different tower dynamics analysis methods and computer codes were used to determine the natural frequencies and mode shapes of both guyed and freestanding wind turbine towers. These analysis methods are described and the results for two types of towers, a guyed tower and a freestanding tower, are shown. The advantages and disadvantages in the use of and the accuracy of each method are also described
A Topos Perspective on State-Vector Reduction
A preliminary investigation is made of possible applications in quantum
theory of the topos formed by the collection of all -sets, where is a
monoid. Earlier results on topos aspects of quantum theory can be rederived in
this way. However, the formalism also suggests a new way of constructing a
`neo-realist' interpretation of quantum theory in which the truth values of
propositions are determined by the actions of the monoid of strings of finite
projection operators. By these means, a novel topos perspective is gained on
the concept of state-vector reduction
Improving Forage Production on Claypan Soils
Mechanical range improvement practices such as contour ripping and furrowing have been used to increase forage production on a variety of range sites in the northern Great Plains. These improvement practices seem to have particular promise on Claypan and Thin Claypan range sites in western South Dakota. Soils on these range sites have a sodium dispersed layer (claypan) at or near the surface. This layer severely reduces the rate of water infiltration, thus causing a greater amount of the precipitation to run off or pool up and evaporate from the soil surface than would happen on soils of similar texture without the claypan layer. Because more precipitation water is lost to runoff and evaporation, less water is available for plant growth. The compact nature of the claypan layer also tends to restrict root growth, further reducing plant growth. Thus, claypan soils are inherently lower in forage production potential than similar soils without the claypan layer. The difference between productivity of the claypan soils and normal soils represents the potential increase in forage production if the effects of the claypan layer could somehow be removed
The Resurgence of Nativism in California? The Case of Proposition 187 and Illegal Immigration
Theory: We argue that support among California voters for Proposition 187 in 1994 was an example of cyclical nativism. This nativism was provoked primarily by California's economic downturn during the early 1990s.
Hypotheses: We develop four specific hypotheses to explain how poor economic conditions in California and the consequent nativistic sentiments would result in support for Proposition 187:
1. voters who believe that California's economic condition is poor will be more likely to support Proposition 187;
2. voters who perceive themselves as being economically threatened by illegal immigrants will be more likely to support Proposition 187;
3. voters with lower levels of education are more economically vulnerable and will be more likely to support Proposition 187;
4. voters in Southern California feel more directly affected by illegal immigration and will be more likely to support Proposition 187.
Methods: To test these hypotheses, we analyze voter exit poll data from the 1994 California election. We utilize a two-stage probit model to allow for the endogeneity which results from the politicization of illegal immigration during this election.
Results: We find support for our hypotheses in the data. These findings cause us to conclude that nativism, fueled by economic conditions, was a salient factor leading many Californians to support Proposition 187
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