6,418 research outputs found
Coupling Nuclear Induced Phonon Propagation with Conversion Electron Mössbauer Spectroscopy
Mössbauer spectroscopy is a very sensitive measurement technique (10-8 eV) which prompted motivation for the experiment described in this thesis. Namely, can a sensitive detection system be developed to detect nuclear recoils on the order of 10 to 100 of eVs? The hypothesis that this thesis tests is: Nuclear induced phonon bursts caused by Rutherford scattered alphas, decayed from 241Am, in a type-310 stainless steel material can couple with 7.3 keV conversion electron Mössbauer events at the other end of the material which will have a statistically significant effect on a Mössbauer spectrum. The phonon bursts produced by the alpha collisions are expected to be very low energy at the other end of length of material. Since Mössbauer spectroscopy is sensitive and can detect the very low energy phonons, the spectrum is expected to change in at least one of the five areas after coupling occurs: broadening in the spectrum peaks, increased/decreased background counting rate, Mossbauer peak asymmetry, increased/decreased counting rate under the peak, and/or a peak centroid shift. This research aims to determine the significance of changes between spectra with phonon bursts and with no phonon bursts through hypothesis testing, where the null hypothesis is where phonons do not affect Mössbauer spectra in one of the five areas mentioned previously. After the spectra and results were analyze using an f-test and t-test comparisons, this experiment failed to reject the null result. Leading to the conclusion that additional research must be conducted
School Chaplaincy is Effective But Could it Be Better?
Analysis of the data collected in the Valuegenesis II study of 3263 students in Seventh-day Adventist schools, indicates that 63% consider the school chaplain has influenced their development of faith. Further, school chaplaincy is associated with statistically significant positive differences in the levels of Faith Maturity, Christian Commitment, Intrinsic Orientation to Religion, Positive Views of God, Denominational Loyalty and Social Responsibility, being a medium to large effect impacting students lives. The potential of reflective practice to improve the outcomes of chaplaincy in the current context of low levels of job satisfaction and chaplaincy retention is considered
The Ultra-Fast Outflow of WKK 4438: Suzaku and NuSTAR X-ray Spectral Analysis
Previous X-ray spectral analysis has revealed an increasing number of AGNs
with high accretion rates where an outflow with a mildly relativistic velocity
originates from the inner accretion disk. Here we report the detection of a new
ultra-fast outflow (UFO) with a velocity of in addition to a relativistic disk reflection
component in a poorly studied NLS1 WKK~4438, based on archival \nustar and
\suzaku observations. The spectra of both \suzaku and \nustar observations show
an Fe~\textsc{xxvi} absorption feature and the \suzaku data also show evidence
for an Ar~\textsc{xviii} with the same blueshift. A super-solar argon abundance
() and a slight iron over-abundance
() are found in our spectral
modelling. Based on Monte-Carlo simulations, the detection of the UFO is
estimated to be around at 3 significance. The fast wind most likely
arises from a radius of away from the central black hole. The disk
is accreting at a high Eddington ratio (). The
mass outflow rate of the UFO is comparable with the disk mass inflow rate
(), assuming a maximum covering factor.
The kinetic power of the wind might not be high enough to have influence in AGN
feedback () due to a relatively
small column density (~cm). However note that
both the inferred velocity and the column density could be lower limits owing
to the low viewing angle ().Comment: 7 pages, 3 figures, accepted by MNRA
Supernova enrichment and dynamical histories of solar-type stars in clusters
We use N-body simulations of star cluster evolution to explore the hypothesis
that short-lived radioactive isotopes found in meteorites, such as 26-Al, were
delivered to the Sun's protoplanetary disc from a supernova at the epoch of
Solar System formation. We cover a range of star cluster formation parameter
space and model both clusters with primordial substructure, and those with
smooth profiles. We also adopt different initial virial ratios - from cool,
collapsing clusters to warm, expanding associations. In each cluster we place
the same stellar population; the clusters each have 2100 stars, and contain one
massive 25M_Sun star which is expected to explode as a supernova at about
6.6Myr. We determine the number of Solar (G)-type stars that are within 0.1 -
0.3pc of the 25M_Sun star at the time of the supernova, which is the distance
required to enrich the protoplanetary disc with the 26-Al abundances found in
meteorites. We then determine how many of these G-dwarfs are unperturbed
`singletons'; stars which are never in close binaries, nor suffer sub-100au
encounters, and which also do not suffer strong dynamical perturbations.
The evolution of a suite of twenty initially identical clusters is highly
stochastic, with the supernova enriching over 10 G-dwarfs in some clusters, and
none at all in others. Typically only ~25 per cent of clusters contain
enriched, unperturbed singletons, and usually only 1 - 2 per cluster (from a
total of 96 G-dwarfs in each cluster). The initial conditions for star
formation do not strongly affect the results, although a higher fraction of
supervirial (expanding) clusters would contain enriched G-dwarfs if the
supernova occurred earlier than 6.6Myr. If we sum together simulations with
identical initial conditions, then ~1 per cent of all G-dwarfs in our
simulations are enriched, unperturbed singletons.Comment: 14 pages, 5 figures, accepted for publication in MNRA
Transformational Education through Intercultural Service Learning Immersions
Theological educators are searching for capstone events and units that will maximise formation and enable ministerial students to find their ministerial identity and style. The contemporary context requires that cultural awareness and intercultural capacities be included in course outcomes. Avondale Seminary has found that intercultural service learning, where reflection is added as an integral facet of learning, provides the desired positive learning outcomes. We have trialled the use of intercultural service learning with selected ministerial students over the last three years to maximise the spiritual and professional formation of our ministerial students deepening their sense of calling and readiness for full-time ministry. Service learning in an overseas context stretched our ministerial students’ communication and relational skills, requiring them to solve multiple problems by adjusting their attitudes, approaches, and ministry skills. The curriculum design has been informed by Meizirow’s and Deardorff’s models and the writings of Tortorici and Gale, Zimmerman and Neyer, Moon, and Bamber and Hankin. Students’ responses, included in the article, reveal deep personal, relational, professional and spiritual growth. The creation of new instruments and processes to enrich the student experience overseas is also explored
Valuation, Adverse Selection, and Market Collapses
We study a market for funding real investment where valuation—meaning investors devoting resources to acquiring information about future payoffs—creates an adverse selection problem. Unlike previous models, more valuation is associated with lower market prices and so greater returns to valuation. This strategic complementarity in the capacity to do valuation generates multiple equilibria. With multiple equilibria, the equilibrium without valuation is most efficient despite funding some unprofitable investments. Switches to valuation equilibria, valuation runs, look like credit crunches. A large investor can ensure the efficient equilibrium only if it can precommit to a price and potentially, only if subsidized
Functional requirements document for the Earth Observing System Data and Information System (EOSDIS) Scientific Computing Facilities (SCF) of the NASA/MSFC Earth Science and Applications Division, 1992
Five scientists at MSFC/ESAD have EOS SCF investigator status. Each SCF has unique tasks which require the establishment of a computing facility dedicated to accomplishing those tasks. A SCF Working Group was established at ESAD with the charter of defining the computing requirements of the individual SCFs and recommending options for meeting these requirements. The primary goal of the working group was to determine which computing needs can be satisfied using either shared resources or separate but compatible resources, and which needs require unique individual resources. The requirements investigated included CPU-intensive vector and scalar processing, visualization, data storage, connectivity, and I/O peripherals. A review of computer industry directions and a market survey of computing hardware provided information regarding important industry standards and candidate computing platforms. It was determined that the total SCF computing requirements might be most effectively met using a hierarchy consisting of shared and individual resources. This hierarchy is composed of five major system types: (1) a supercomputer class vector processor; (2) a high-end scalar multiprocessor workstation; (3) a file server; (4) a few medium- to high-end visualization workstations; and (5) several low- to medium-range personal graphics workstations. Specific recommendations for meeting the needs of each of these types are presented
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