Vibration characteristics of 1/8-scale dynamic models of the space-shuttle solid-rocket boosters

Vibration tests and analyses of six 1/8 scale models of the space shuttle solid rocket boosters are reported. Natural vibration frequencies and mode shapes were obtained for these aluminum shell models having internal solid fuel configurations corresponding to launch, midburn (maximum dynamic pressure), and near endburn (burnout) flight conditions. Test results for longitudinal, torsional, bending, and shell vibration frequencies are compared with analytical predictions derived from thin shell theory and from finite element plate and beam theory. The lowest analytical longitudinal, torsional, bending, and shell vibration frequencies were within + or - 10 percent of experimental values. The effects of damping and asymmetric end skirts on natural vibration frequency were also considered. The analytical frequencies of an idealized full scale space shuttle solid rocket boosted structure are computed with and without internal pressure and are compared with the 1/8 scale model results

Promoting Immigrant and Human Rights at the Local Level: A Case Study of the Welcome Dayton Initiative (abstract)

Hazelton, Pennsylvania and Dayton, Ohio represent contrasting examples of community reactions to increases in immigrants. Both cities have experienced de-manufacturing in recent decades. In reaction to an influx of Latinos, Hazelton enacted the 2006 Illegal Immigration Relief Act (IIRA) which placed severe restrictions on the rights of undocumenteds. In contrast, the Dayton City Commission passed the Welcome Dayton: Immigrant-Friendly City initiative in 2011 with the goal of facilitating the integration of immigrant residents. Hazelton’s developers used tax incentives to establish warehouses, distribution centers, and a meatpacking plant, resulting in a significant demographic change. However, in adopting a neoliberal approach, the developers failed to provide support for emerging Latina/o-owned small businesses. The results have implications for economic justice and the protection of the rights of immigrant laborers. Also, Hazelton illustrates the limitations of legal challenges to restrictive legislation. Although the law was challenged and subsequently ruled unconstitutional, a local White-Latina/o organization attempting to \u27build a bridge\u27 between recent immigrants and local residents/institutions has been constrained from raising issues like race and immigrant rights. Consequently, the dominant narrative goes unchallenged and core factors — racial and economic inequality — remain in place. In contrast, the Welcome Dayton initiative was resulted from ongoing efforts by numerous local organizations, including those of immigrants and refugees themselves, to assist recent immigrants and protect their rights. When the City’s Human Relations Council initiated community conversations on immigrant issues, there were many participants with experience to guide the writing of a comprehensive report with extensive recommendations for institutional change. Once begun, Welcome Dayton’s initiatives have partnered with local organizations. Whether intentional or not, Dayton and cities with similar initiatives are acting in accord with the U.N.’s 1990 International Convention on the Protection of the Rights of All Migrant Workers and Members of Their Families, especially the articles specifying equal access to educational, vocational and social services and equality of living and working conditions and employment contracts. These two cases reflect the contrast between citizen rights, which often stress individual rights and sometimes pit groups against each other, and human rights based on principles of social justice and the well-being of the human person

Fear and Resistance Far from the Border: Human Rights and Student Engagement in Immigrant and Refugee Communities in Dayton, Ohio

Similar to articles 23-27 of the UDHR, articles 25-31 of the 1990 International Convention on the Protection of the Rights of All Migrant Workers and Members of Their Families specify equal access by immigrants to educational, vocational & health/social services and equality of living and working conditions and employment contracts. Beginning in 2007, Professor Majka has involved students in his immigration classes in research on the challenges and obstacles immigrants and refugees in the Dayton area experience relevant for those areas specified by the Convention. Joined by students in Professor Linda Majka classes, students arranged and conducted interviews with representatives of Dayton-area immigrant and refugee communities and with staff of human service agencies who work with these communities. Students also helped organize and observed focus groups of specific populations. Students in Professor Hallett’s Anthropology of Human Rights class participated in the latest research beginning in 2017. In this presentation, we will describe two outcomes of student engagement. One is the impact on the students themselves. All described their participation as genuine learning experiences. Besides putting human faces on class materials, some described it as transformative. Interviewing prepared several for travel to the countries of origin of some interviewees, e.g. Mexico and El Salvador. Some found their experiences useful for post-graduate plans, e.g. volunteering, law school and MSW programs. Others made public presentations. The interviews have provided the basis of several senior research projects and honors theses. We will provides quotes from students’ reflections. The second is the impact on the larger community. The research findings have resulted in 4 conferences (2008, 2009, 2012 and 2019) that brought together Dayton-area residents, including many leaders and elected officials, with leaders of immigrant and refugee communities. The first two conferences helped provide the momentum that resulted in the 2011 Welcome Dayton initiative

Impacts of the Trump Administration’s Policies on Immigrants and Refugees in Dayton

The Trump administration’s executive orders and policy changes regarding refugee resettlement and stepped-up Immigration and Customs Enforcement (ICE) actions are likely to create serious human rights and humanitarian impacts. These include separation of children from their parents, denial of due process in immigration courts, lengthy incarceration in detention centers, denial or loss of employment, denial of visas to citizens of some predominantly Muslim countries, denial of entry to previously vetted refugees scheduled for resettlement, and return (refoulment) of persons with well-founded fears of persecution or torture. These actions will potentially impact key human rights areas and concerns, such as nondiscrimination, equality before the law, equal protection of the law, protection against arbitrary punishment, the right to asylum, and the special protections accorded to families. They involve the Universal Declaration of Human Rights, the Covenant on Civil and Political Rights, the Convention on the Elimination of All Forms of Racial Discrimination, and refugee and torture conventions protecting rights to asylum and protection from deportation when that is likely to result in persecution, torture, or death. In this presentation, we will share the results of a study examining impacts of the administration’s actions on immigrant and refugee populations in the Dayton, Ohio, area. Impacts may include increased fear and stress and changes in daily routines; detention or deportation; family separation; economic hardships; increased instances of discrimination and harassment; difficulty accessing institutional services; and restrictions on mobility or visits from family. The research involves interviews with leaders of local immigrant and refugee communities and focus groups conducted with members of these communities during spring, summer, and early fall 2017. Staff of human service agencies who work with these communities will also be interviewed to examine the role of local institutions as intermediaries. The research team includes faculty and undergraduate students from the University of Dayton

Saturation effect and determination of nuclear matter denisity distribution from optical potential

A refined double folding procedure with density dependence of the effective nucleon- -nucleon interaction included is used to calculate the real part of the alpha particle — $^{48,40}$Ca potentials. We show that the experimentally determined difference between rms radii of the (real) potentials implies a larger size of the nuclear matter distribution of the $^{48}$Ca nucleus as compared to the $^{40}$Ca nucleus

Carbonate alteration of ophiolitic rocks in the Arabian–Nubian Shield of Egypt: sources and compositions of the carbonating fluid and implications for the formation of Au deposits

Ultramafic portions of ophiolitic fragments in the Arabian–Nubian Shield (ANS) show pervasive carbonate alteration forming various degrees of carbonated serpentinites and listvenitic rocks. Notwithstanding the extent of the alteration, little is known about the processes that caused it, the source of the CO2 or the conditions of alteration. This study investigates the mineralogy, stable (O, C) and radiogenic (Sr) isotope composition, and geochemistry of suites of variably carbonate altered ultramafics from the Meatiq area of the Central Eastern Desert (CED) of Egypt. The samples investigated include least-altered lizardite (Lz) serpentinites, antigorite (Atg) serpentinites and listvenitic rocks with associated carbonate and quartz veins. The C, O and Sr isotopes of the vein samples cluster between −8.1‰ and −6.8‰ for δ13C, +6.4‰ and +10.5‰ for δ18O, and 87Sr/86Sr of 0.7028–0.70344, and plot within the depleted mantle compositional field. The serpentinites isotopic compositions plot on a mixing trend between the depleted-mantle and sedimentary carbonate fields. The carbonate veins contain abundant carbonic (CO2±CH4±N2) and aqueous-carbonic (H2O-NaCl-CO2±CH4±N2) low salinity fluid, with trapping conditions of 270–300°C and 0.7–1.1 kbar. The serpentinites are enriched in Au, As, S and other fluid-mobile elements relative to primitive and depleted mantle. The extensively carbonated Atg-serpentinites contain significantly lower concentrations of these elements than the Lz-serpentinites suggesting that they were depleted during carbonate alteration. Fluid inclusion and stable isotope compositions of Au deposits in the CED are similar to those from the carbonate veins investigated in the study and we suggest that carbonation of ANS ophiolitic rocks due to influx of mantle-derived CO2-bearing fluids caused break down of Au-bearing minerals such as pentlandite, releasing Au and S to the hydrothermal fluids that later formed the Au-deposits. This is the first time that gold has been observed to be remobilized from rocks during the lizardite–antigorite transition

Towards ultra-high resolution 3D reconstruction of a whole rat brain from 3D-PLI data

3D reconstruction of the fiber connectivity of the rat brain at microscopic scale enables gaining detailed insight about the complex structural organization of the brain. We introduce a new method for registration and 3D reconstruction of high- and ultra-high resolution (64 $\mu$m and 1.3 $\mu$m pixel size) histological images of a Wistar rat brain acquired by 3D polarized light imaging (3D-PLI). Our method exploits multi-scale and multi-modal 3D-PLI data up to cellular resolution. We propose a new feature transform-based similarity measure and a weighted regularization scheme for accurate and robust non-rigid registration. To transform the 1.3 $\mu$m ultra-high resolution data to the reference blockface images a feature-based registration method followed by a non-rigid registration is proposed. Our approach has been successfully applied to 278 histological sections of a rat brain and the performance has been quantitatively evaluated using manually placed landmarks by an expert.Comment: 9 pages, Accepted at 2nd International Workshop on Connectomics in NeuroImaging (CNI), MICCAI'201

Detrital zircon U-Pb geochronology of a metasomatic calc-silicate in the Tsäkkok Lens, Scandinavian Caledonides

The Tsäkkok Lens of the Seve Nappe Complex in the Scandinavian Caledonides comprises eclogite bodies hosted within metasedimentary rocks. These rocks are thought to be derived from the outermost margin of Baltica along the periphery of the Iapetus Ocean, but detrital records from the sedimentary rocks are lacking.Many metasedimentary outcrops within the lens expose both well-foliated metapelitic rocks and massive calc-silicates. The contacts between these two lithologies are irregular and are observed to trend at all angles to the high-pressure foliation in the metapelites. Where folding is present in the metapelites, the calc-silicate rocks are also locally folded. These relationships suggest metasomatism of the metapelites during the Caledonian orogenesis. Zircon U-Pb geochronology was conducted on sixty-one zircon grains from a calc-silicate sample to investigate if they recorded the metasomatic event and to assess the detrital zircon populations. Zircon grains predominantly show oscillatory zoning, sometimes with thin, homogeneous rims that have embayed contacts with the oscillatory-zoned cores. The zircon cores yielded prominent early Stenian, Calymmian, and Statherian populations with a subordinate number of Tonian grains. The zircon rims exhibit dissolution-reprecipitation of the cores or new growth and provide ages that span similar time frames, indicating overprinting of successive tectonic events. Altogether, the zircon record of the calc-silicate suggests that the Tsäkkok Lens may be correlated to Neoproterozoic basins that are preserved in allochthonous positions within the northern extents of the Caledonian Orogen

Multilevel Monte Carlo methods for the approximation of invariant measures of stochastic differential equations

We develop a framework that allows the use of the multi-level Monte Carlo (MLMC) methodology (Giles2015) to calculate expectations with respect to the invariant measure of an ergodic SDE. In that context, we study the (over-damped) Langevin equations with a strongly concave potential. We show that, when appropriate contracting couplings for the numerical integrators are available, one can obtain a uniform in time estimate of the MLMC variance in contrast to the majority of the results in the MLMC literature. As a consequence, a root mean square error of $\mathcal{O}(\varepsilon)$ is achieved with $\mathcal{O}(\varepsilon^{-2})$ complexity on par with Markov Chain Monte Carlo (MCMC) methods, which however can be computationally intensive when applied to large data sets. Finally, we present a multi-level version of the recently introduced Stochastic Gradient Langevin Dynamics (SGLD) method (Welling and Teh, 2011) built for large datasets applications. We show that this is the first stochastic gradient MCMC method with complexity $\mathcal{O}(\varepsilon^{-2}|\log {\varepsilon}|^{3})$, in contrast to the complexity $\mathcal{O}(\varepsilon^{-3})$ of currently available methods. Numerical experiments confirm our theoretical findings.Comment: 25 pages, 8 figure

An experimental survey of the production of alpha decaying heavy elements in the reactions of 238^{238}U +232^{232}Th at 7.5-6.1 MeV/nucleon

The production of alpha particle decaying heavy nuclei in reactions of 7.5-6.1 MeV/nucleon $^{238}$U +$^{232}$Th has been explored using an in-beam detection array composed of YAP scintillators and gas ionization chamber-Si telescopes. Comparisons of alpha energies and half-lives for the observed products with those of the previously known isotopes and with theoretically predicted values indicate the observation of a number of previously unreported alpha emitters. Alpha particle decay energies reaching as high as 12 MeV are observed. Many of these are expected to be from decay of previously unseen relatively neutron rich products. While the contributions of isomeric states require further exploration and specific isotope identifications need to be made, the production of heavy isotopes with quite high atomic numbers is suggested by the data.Comment: 12 pages, 12 figure