X-Ray Measurement and Porosity in Graphite/Polyimide Composites

One of the persistent problems in the control of quality in materials used in structures is that of porosity. Whether the material is a casting, an epoxy composite, or a complex ceramic or metal matrix composite, the presence of porosity, depending upon the severity, causes a degradation of the parts performance characteristics and their longevity. The detection of porosity in many industries is important in two ways, namely, in material quality control and in monitoring process control (1). One class of materials where both of these problems arise is the graphite composites (2–4). To date, the inspection of these composites using an X-ray method has been unsatisfactory in that the film methods frequently tried did not have the sensitivity resolution to yield a quantitative measure of the porosity volume percent. Such a measure becomes even more critical in ceramic composites in that the difference between a good material and a poor one is a level of porosity rather than the presence of porosity, as is the case in graphite epoxy composites. We wish to report results of an X-ray method to measure porosity in materials using the graphite polyimide composites as an example. The method is certainly not restricted to this type of graphite composite or indeed to graphite composites

Heavy Metal Contamination Detection Using X-Rays

Within the DOE complex there are large quantities of radioactive and hazardous chemical waste that exist in a broad variety of forms, toxicity, and storage conditions. There are 3700 contaminated sites, with 500 facilities now surplus, and as many as 7000 expected to be declared surplus in the coming decades[1]. Most of these facilities will require cleanup of hazardous waste before decommissioning. Efficient, safe, cost-effective methods of characterization are needed to assist in the timely cleanup of these sites. Due to the hazardous nature of the contaminants, a nondestructive non-invasive technique is preferred for characterization and for monitoring the decontamination processes

A Novel Image Processing Algorithm for Enhancing the Probability of Detection of Flaws in X-Ray Images

Application of Digital Signal Processing (DSP) techniques in x-ray radiography is a field that is gaining a rapidly growing interest. Dealing with digital x-ray images and enhancing these images using DSP techniques allow the automation of x-ray inspection, which offers several advantages over the traditional film-based inspection. These advantages include reducing the inspection time and cost requirements, obtaing a consistent decision regarding the integrity of the object under test, and allowing the use of real-time inspection [1]. Typically processing of x-ray images to detect and size flaws involves edge detection. In this paper, we primarily focus on an image processing algorithm that is based on a new Gaussian weighted image moment vector edge operator. Application of this operator enhances image edges and suppresses the noise, which results in a significant improvement in the probability of detection of flaws in x-ray images

Probing the Space of Toric Quiver Theories

We demonstrate a practical and efficient method for generating toric Calabi-Yau quiver theories, applicable to both D3 and M2 brane world-volume physics. A new analytic method is presented at low order parametres and an algorithm for the general case is developed which has polynomial complexity in the number of edges in the quiver. Using this algorithm, carefully implemented, we classify the quiver diagram and assign possible superpotentials for various small values of the number of edges and nodes. We examine some preliminary statistics on this space of toric quiver theories

HIV infection in rural households, Rakai district, Uganda

The Rakai Project conducted a population-based cohort study in rural Rakai District, Uganda, a region with high rates of HIV prevalence. The cohort population described here was followed between 1990 and 1992 and consisted of all residents aged 15 years or more living in 1945 households in 31 community clusters. A detailed census was conducted at baseline in every study household. Census data were updated annually, and all inter-survey deaths, births, and migrations were recorded. Immediately following each annual census, all consenting adults were administered a socio-demographic, behavioural and health survey, and provided a blood sample for HIV testing. HIV prevalence in the study population was high, with 19.1 per cent of adults aged 15 or more years being HIV-positive. By household, the burden of infection was even more pronounced: 31.3 per cent of households had at least one HIV-infected resident adult. Twenty seven per cent of heads of households were also HIV-positive. Overall, 3.6 per cent of study households experienced the death of an HIV-positive adult per year, and another two per cent lost an HIV-negative adult. HIV-related adult mortality had substantially more effect on subsequent household dependency ratio and on material possessions than the death of an HIV-uninfected adult, in part because the former deaths were concentrated in adults aged 15-49, the most economically active age group in this rural population. Just under 15 per cent of children aged 14 years or less had lost one or both parents, and approximately half of these parental losses are estimated to be associated with HIV infection. Nineteen per cent of study households reported at least one resident child who had lost one or both parents. Although there is evidence that loss of a parent is associated with lower school attendance, orphans overall continue to be absorbed by community households which are headed by adults. HIV infection is very prevalent among adults in Rakai and the associated mortality imposes a substantial social and economic burden on households in the district

Hyperstrong Radio-Wave Scattering in the Galactic Center. II. A Likelihood Analysis of Free Electrons in the Galactic Center

The scattering diameters of Sgr A* and several nearby OH masers (~ 1" at 1 GHz) indicate that a region of enhanced scattering is along the line of sight to the Galactic center. We combine radio-wave scattering data and free-free emission and absorption measurements in a likelihood analysis that constrains the following parameters of the GC scattering region: The GC-scattering region separation, d; the angular extent of the region, \psi_l; the outer scale on which density fluctuations occur, l_0; and the gas temperature, T. The maximum likelihood estimates of these parameters are d = 133_{-80}^{+200} pc, 0.5 degrees <= \psi_l <~ 1 degrees, and (l_0/1 pc)^{2/3}T^{-1/2} = 10^{-7 +/- 0.8}. As host media for the scattering, we consider the photoionized surface layers of molecular clouds and the interfaces between molecular clouds and the 10^7 K ambient gas. We are unable to make an unambiguous determination, but we favor an interface model in which the scattering medium is hot (T ~ 10^6 K) and dense (n_e ~ 10 cm^{-3}). The GC scattering region produces a 1 GHz scattering diameter for an extragalactic source of 90", if the region is a single screen, or 180", if the region wraps around the GC, as appears probable. We modify the Taylor-Cordes model for the Galactic distribution of free electrons in order to include an explicit GC component. Pulsars seen through this region will have a dispersion measure of approximately 2000 pc cm^{-3}, of which 75% arises from the GC component. We stress the uniqueness of the GC scattering region, probably resulting from the high-pressure environment in the GC.Comment: 39 pages with 9 PostScript figures; LaTeX2e with AASTeX macro aaspp4, to be published in Ap

Conservation Targeting: Models and Policy for Climate Resilience of coastal habitat and heritage resources in Virginia’s Coastal Zone

In response to accelerating sea level rise and its anticipated impacts on coastal habitats and species, we developed spatial models and maps of shoreline habitat distributions in Coastal Virginia to the year 2100. This report is a culmination of a three-year effort to develop and serve geospatial data to inform land use decision making within the context of projected habitat and current elemental occurrences to promote habitat and species persistence and resilience. The project was a collaboration of the Center for Coastal Resources Management (CCRM) at the Virginia Institute of Marine Science (VIMS the Virginia Department of Conservation and Recreation, Virginia Natural Heritage Program (DCR VNHP) and the former Virginia Coastal Policy Center (VCPC). The report is organized around the tasks and products for each member of the project team. The first section is reporting efforts by CCRM, followed by content describing the work done by DCR VNHP. Policy analysis by VCPC follows next with summary and conclusion by CCRM last. The complete report from DCR VNHP is included in Appendix 3

KSU Chamber Singers, A Litany for Courage and the Seasons

Kennesaw State University Chamber Singers present David Maslanka\u27s A Litany for Courage and the Seasons, six songs for chorus, clarinet and vibraphone on poems of Richard Beale at the 2013 National Collegiate Choral Organization 5th National Conference in Charleston, South Carolina, October 31 - November 2.https://digitalcommons.kennesaw.edu/musicprograms/1268/thumbnail.jp

KSU Chamber Singers and Men\u27s Ensemble

KSU School of Music presents KSU Chamber Singers and Men\u27s Ensemble.https://digitalcommons.kennesaw.edu/musicprograms/1294/thumbnail.jp

Finding Radio Pulsars in and Beyond the Galactic Center

Radio-wave scattering is enhanced dramatically for Galactic center sources in a region with radius >~ 15 arc min. Using scattering from Sgr A* and other sources, we show that pulse broadening for pulsars in the Galactic center is {\em at least} 6.3 \nu^{-4} seconds (\nu = radio frequency in GHz) and is most likely 50--200 times larger because the relevant scattering screen appears to be within the Galactic center region itself. Pulsars beyond---but viewed through---the Galactic center suffer even greater pulse broadening and are angularly broadened by <~ 2 {\em arc min}. Periodicity searches at radio frequencies are likely to find only long period pulsars and, then, only if optimized by using frequencies >~ 7 GHz and by testing for small numbers of harmonics in the power spectrum. The optimal frequency is $\nu ~ 7.3 GHz (\Delta_{0.1}P\sqrt{\alpha})^{-1/4}$ where \Delta_{0.1} is the distance of the scattering region from Sgr A* in units of 0.1 kpc, P is the period (seconds), and \alpha is the spectral index. A search for compact sources using aperture synthesis may be far more successful than searches for periodicities because the angular broadening is not so large as to desensitize the survey. We estimate that the number of {\em detectable} pulsars in the Galactic center may range from <= 1 to 100, with the larger values resulting from recent, vigorous starbursts. Such pulsars provide unique opportunities for probing the ionized gas, gravitational potential, and stellar population near Sgr A*.Comment: 13 pages, 4 PS figures, LaTeX and requires AASTeX macro aas2pp4, accepted by ApJ, also available as http://astrosun.tn.cornell.edu/SPIGOT/papers/pulsar/gc_psr.web