5,550 research outputs found
Graphite/Larc-160 technology demonstration segment test results
A structural test program was conducted on a Celion/LARC-160 graphite/polyimide technology demonstration segment (TDS) to verify the technology. The 137 x 152 cm (54 x 60 in.) TDS simulates a full-scale section of the orbiter composite body flap design incorporating three ribs and extending from the forward cove back to the rear spar. The TDS was successfully subjected to mechanical loads and thermal environments (-170 to 316 C) simulating 100 shuttle orbiter missions. Successful completion of the test program verified the design, analysis, and fabrication methodology for bonded Gr/PI honeycomb sandwich structure and demonstration that Gr/PI composite technology readiness is established
Modeling acoustic waves with paraxial extrapolators
Modeling by paraxial extrapolators is applicable to wave-propagation problems in which most of the energy is traveling within a restricted angular cone about a principal axis of the problem. Using this technique, frequency-domain finite-difference solutions accurate for propagation angles out to 60° are readily generated for both two-dimensional (2-D) and three-dimensional (3-D) models. Solutions for 3-D problems are computed by applying the 2-D paraxial operators twice, once along the x-axis and once along the y-axis, at each extrapolation step. The azimuthal anisotropy inherent to this splitting technique is essentially eliminated by adding a phase-correction operator to the extrapolation system. For heterogeneous models, scattering effects are incorporated by determining transmission and reflection coefficients at structural boundaries within the media. The direct forward-scattered waves are modeled with a single pass of the extrapolation operator in the paraxial direction for each frequency. The first-order backscattered energy is then modeled by extrapolation (in the opposite direction) of the reflected field determined on the first pass. Higher order scattering can be included by sweeping through the model with more passes. The chief advantages of the paraxial approach are (1) active storage is reduced by one dimension compared to solutions which must track both forward-scattered and backscattered waves simultaneously; thus, realistic 3-D problems can fit on today's computers, (2) the decomposition in frequency allows the technique to be implemented on highly parallel machines, (3) attenuation can be modeled as an arbitrary function of frequency, and (4) only a small number of frequencies are needed to produce movie-like time slices
The provenance of tills overlying the eastern part of the South Mountain Batholith, Nova Scotia
Happing of quarternary deposits on the South Mountain Batholitb (SMB) has resulted in a four-fold subdivision of tills, divided primarily on the basis of clast lithology, texture, stratigraphic position and morphology.
Three tills have clast lithologies characterized by granites eroded from the South Mountain Batholih. The oldest granite till is a compact till of restricted distribution, mianly observed In drumlin cores. Two younger granite tills dominate the surficial deposits of portions of the SMB and have textural properties ascribed to melt-out tills. The fourth till represents a farther-travelled till with a variable clast provenance typified by pebbles derived from both the SMB and regions to the north. Clast dispersal evidence suggests that all tills were transported in a general southward direction.
Detailed clast examinations allow reliable conclusions concerning direction of Ice flow and lithologic relationship between till and bedrock of the SMB. The SMB is an area of multiple glaciatlon where till prospecting cannot be successful unless the direction of till transport and source areas are established.
RÉSUMÉ
Dn levé cartographique des dépôts quaternaires recouvrant le Batholite de South Mountain à permis de mettre en évidence quatre varlétés de tills en fonctlon de la lithologie des clastes, la texture, la position stratlgraphlque et la morphologic
Dana trola tills, les clastes nontrent des lithologles caractérisées par des granites arrachés au Batholite de South Mountain (BSM). Le plus vleux till de granite est un till tasse. de faible étendue, observe surtout dans les noyaux de drumlins. Dans certaines portions du BSM, les dépôts de surface sont dominés par deux tills de granite plus recents qui possedent des caractéristlques texturales rapportées aux tills d'ablation. Le quatriéme till a parcouru une plus grande distance; la source de ses clastes est variable et comprend typiquement des galets provenant tant du BSM que des régions plus au nord. La dispersion des blocaux suggère un direction générale de transport des tills vers le sud.
Un exanen approfondi des clastes permet de tirer de solides conclusions à propos de la direction de l’écouleroent glacialre et de la relation lithologique entre le till et le socle du BSM. Le BSM a subi de multiples glaciatlons et la prospection du till n'y est done guère profitable à molns de déterminer la direction de transport et la source du till.
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Millisecond accuracy video display using OpenGL under Linux
To measure people’s reaction times to the nearest millisecond, it is necessary to know exactly when
a stimulus is displayed. This article describes how to display stimuli with millisecond accuracy on a
normal CRT monitor, using a PC running Linux. A simple C program is presented to illustrate how this
may be done within X Windows using the OpenGL rendering system. A test of this system is reported
that demonstrates that stimuli may be consistently displayed with millisecond accuracy. An algorithm
is presented that allows the exact time of stimulus presentation to be deduced, even if there are relatively
large errors in measuring the display time
Strengthening Community Foundations - Redefining the Opportunities
Commissioned by the Council on Foundations and released in October 2003, this white paper details the findings and the implications of our study of costs and revenues at nine community foundations. Offering a new perspective for community foundation sustainability, the white paper proposes that community foundations examine their strategy and operations on a product-by-product basis, taking into account their mission-driven priorities, internal costs, customer preferences and the competing donor alternatives for each type of product or service they offer
Forensic Pavement Evaluation for US 31 W, Jefferson County, Kentucky Using Ground Penetrating Radar
The Kentucky Transportation Center (KTC) utilized ground penetrating radar technology to provide a forensic evaluation of the existing pavement structure for the US31W pavement rehabilitation Project in Jefferson County, KY. Processed ground penetrating radar data indicated that the integrity of the underlying concrete pavement beneath the asphalt pavement appears to be competent and structurally sound. The clay soil beneath the concrete pavement appears relatively dry and well compacted. The analyzed GPR data also indicated that the average asphalt layer varied by lane throughout the project from 4.89 to 7.59 inches +/- ½ inch and that the underlying concrete layer average varied by lane throughout the project from 6.59 to 8.12 inches +/- ½ inch. This information was shared with design engineers in efforts to select the most appropriate pavement rehabilitation repair
Economic Impact of Heavy Loads On the Highway Infrastructure
During the 1986 General Assembly the Extended-Weight Coal Haul Road System was created by the Kentucky State Legislature. This system was defined to include those highways where more than 50,000 tons of coal had been hauled during the previous year. Trucks hauling coal on the extended-weight system were authorized to exceed the normal weights limits through the payment of an annual decal fee.
In efforts to identify the benefactors of the extended coal haul system legislation, this study has been conducted to identify the overall economic impact of hauling heavier total gross weights by coal truck on the highway infrastructure in Kentucky in 1996. In order to identify the overall economic impact of hauling heavier weights by coal truck an economic analysis had to be preformed. This economic analysis compared the monetary benefits achieved by all users for hauling heavier weights by coal truck to the additional expenses incurred by allowing heavier weights to be hauled on the highway infrastructure
Pursuit of purity: Measurement of chelation binding affinities for NOTA, DOTA, and desferal with applications to effective specific activity
Introduction
The effective specific activity of a radioisotope is an indirect and highly useful way to describe a radioactive sample’s purity. A high effective specific activity combines the concept of an isotopically pure product with suitability via selectivity of a particular chelating body. The primary goals of this work are twofold: 1) To determine which metallic impurities have the largest impact on the effective specific activity for a given chelator, and 2) to form a model based on the binding affinities of each metal for to calculate a ‘theoretical effective specific activ-ity’ from broad band trace metal analysis. If successful, this information can be used to guide the production of high specific activity products through the systematic elimination of high-impact metallic impurities.
Material and Methods
Phosphor plate thin layer chromatography (TLC) was used to measure the effective specific activ-ity of 64Cu by NOTA and DOTA, and 89Zr by des-feral (DF). Typical measured effective specific activities are 2–5 Ci/μmol for 64Cu and 1–2 Ci/μmol for 89Zr.
Samples were created containing increasing cod competitive burdens (X) of CuCl2, ZnCl2, FeCl2, NiCl2, CrCl3, CoCl2, MnCl2, and YCl3. Standard concentrations were measured by microwave plasma atomic emission spectrometry. 50 pmol of NOTA, DOTA, or DF were added following the activity aliquots of 64Cu or 89Zr. Labeling efficien-cies (64Cu-NOTA, 64Cu-DOTA, 89Zr-DF) were measured using TLC’s, and were fit by linear regression to the form f(X) = b/(1 − AX), where A is the chelation affinity (inverse of dissociation constant) and X is the molar ratio of the metallic impurity to the amount of chelator.
Results and Conclusion
Affinity of Zr for DF was assumed to be unity, while the affinities of Cu for NOTA and DOTA were explicitly measured and were found to be 0.93 ± 0.13 and 5.2 ± 3.2 respectively.
It was found that Cu had the highest affinity for NOTA by a factor of 266, and that Zr had the highest affinity for DF by a factor of 40.
• In order of decreasing affinity to NOTA: Cu, Zn, Fe, Co, Cr, Y, and Ni
• In order of decreasing affinity to DOTA: Cu, Y, Zn, Co, Ni, Cr, and Fe
• In order of decreasing affinity to DF: Zr, Y, Cu, Zn, Ni, Fe, Co, Cr
These results suggest that aside from the carrier element it is most important to remove zinc from 64Cu products prior to chelation with NOTA and yttrium from 64Cu and 89Zr products prior to chelation with DOTA and DF, respectively. Therefore, it is logical to believe that 89Zr effective specific activities could be greatly improved by secondary separations with the goal of re-moving additional yttrium target material.
Chelation affinities of NOTA, DOTA, and DF for several common metals have successfully been investigated. These values will guide our future attempts to provide high effective specific activity 64¬Cu and 89Zr. Furthermore, a preliminary model has been formed to calculate effective specific activity from the quantitative broad band analysis of trace metals. Future work will include chelator affinity measurements for other likely contaminants, such as scandium, titanium, zirconium, molybdenum, niobium, gold, gallium, and germanium. Details will be presented
Glossolalia : mental health and locus of control
The present study focussed on three major areas of
interest: the relationship between glossolalia, or speaking
in tongues, and positive mental health; the relationship
between glossolalia and locus of control; and finally, the
use of Rotter's original locus of control scale with highly
religious populations.
Ninety subjects were assigned to four groups on the
basis of self-report data. The Old Tongues group was
comprised of actively practising Christians who had been
glossolalic for more than three years, while those in the
Young Tongues group had been glossolalic for three years or
less. Subjects in the No Tongues group were actively
practising Christians yet non-glossolalic. Finally, subjects
in the No Religion group were self-described atheists or
agnostics and non-glossolalic. All subjects completed three
paper and pencil instruments; Rotter's (1966) Social
Reaction Inventory (SRI), Shostrom's (1963, 1964, 1966)
Personal Orientation Inventory (POI), and finally, an
original survey questionnaire prepared by the author and
dealing with selected aspects of the respondents' family and
personal backgrounds, and religious experiences and beliefs
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