694 research outputs found
Perceptions Of Consensual Sexual Student-Faculty Relationships
Consensual, sexual relationships (CSRs) involving university faculty members and students are not uncommon (Richards et al., 2014). Given the increased attention of sexual harassment on college campuses, a number of universities have implemented CSR policies that generally fall into three categories: total ban, limited ban, and discouragement. Despite the intention of these policies,--the prevention of sexual assault and harassment--they have been criticized for being vague and too general (Bellas & Gosset, 2001; Jafar, 2003). Examining student perceptions can provide inside into university culture and inform policymaking. To this end, participants were randomly assigned to one of four conditions stemming from a 2 (romantic dyad: male professor/female student vs. female professor/male student) x 2 (student status: undergraduate vs. graduate) between-subjects factorial design, asked to read a vignette, and respond to a series of questions designed to measure perceptions of CSRs, those involved in them, and the policies that concern them. It was hypothesized that perceptions of CSRs involving a female student would be viewed significantly more negatively than the relationship involving the male student. This was anticipated to especially be the case when the female student is an undergraduate student as opposed to a graduate student. Results did not support the hypotheses. Reasons for null findings, limitations, and suggestions for future research are discussed
Development of Cardanol-based Epoxy Coating
The purpose of this project was to determine the suitability of cardanol glycidyl ether (CGE) as a substitute for trimethylolpropane triglycidyl ether (TMPGE) as the reactive diluent in epoxy coatings. CGE may be a naturally-derived alternative to TMPGE, which is a commonly-used petroleum-derived reactive diluent. Epoxy coatings were formulated with CGE replacing increasing amounts of TMPGE in the formulation. Corrosion protection provided by the coatings was evaluated with electrochemical impedance spectroscopy (EIS). Mechanical properties of the coatings (hardness, flexibility, adhesion, and impact resistance) were evaluated with applicable ASTM standards.
EIS results revealed the coating formulated with only CGE had superior corrosion protection when compared to the control formulated with only TMPGE. The control exhibited greater hardness when compared to the coating formulated with only CGE. No measurable differences could be determined within the scopes of the flexibility, adhesion, and impact resistance tests. The results suggest that CGE may be a suitable substitute for TMPGE in epoxy coatings, especially if very good corrosion protection is desired
State transitions and jet formation in black hole binaries
The daily monitoring observations of black hole transients with RXTE provided important clues on the conditions of the state transitions, both in terms of spectra and timing. The recent addition of monitoring in the optical-infrared and the radio band significantly extended our knowledge of the relation between the jets and the spectral states. However, there are still very important unanswered questions, most importantly, whether the formation of the jet triggers any change in the spectral and temporal properties of the source. The answer to this question is also intrinsically related to the origin of the hard X-ray emission. In this work, the relation between the jet and the state transitions is discussed, using the data from GX 339-4, 4U 1543-47, H 1743-322, and GRO J1655-40, concentrating on the evolution of spectral and temporal parameters before, during and after the formation of the jet
RX J0440.9+4431: a persistent Be/X-ray binary in outburst
The persistent Be/X-ray binary RX J0440.9+4431 flared in 2010 and 2011 and
has been followed by various X-ray facilities Swift, RXTE, XMM-Newton, and
INTEGRAL. We studied the source timing and spectral properties as a function of
its X-ray luminosity to investigate the transition from normal to flaring
activity and the dynamical properties of the system. We have determined the
orbital period from the long-term Swift/BAT light curve, but our determinations
of the spin period are not precise enough to constrain any orbital solution.
The source spectrum can always be described by a bulk-motion Comptonization
model of black body seed photons attenuated by a moderate photoelectric
absorption. At the highest luminosity, we measured a curvature of the spectrum,
which we attribute to a significant contribution of the radiation pressure in
the accretion process. This allows us to estimate that the transition from a
bulk-motion-dominated flow to a radiatively dominated one happens at a
luminosity of ~2e36 erg/s. The luminosity dependency of the size of the black
body emission region is found to be . This
suggests that either matter accreting onto the neutron star hosted in RX
J0440.9+4431 penetrates through closed magnetic field lines at the border of
the compact object magnetosphere or that the structure of the neutron star
magnetic field is more complicated than a simple dipole close to the surfaceComment: Accepted for publication by A&
Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state
Hard X-ray spectra of black hole binaries in the low/hard state are well
modeled by thermal Comptonization of soft seed photons by a corona-type region
with \thinspace{\thinspace}keV and optical depth around 1.
Previous spectral studies of 1E{\thinspace}1740.72942, including both the
soft and the hard X-ray bands, were always limited by gaps in the spectra or by
a combination of observations with imaging and non-imaging instruments. In this
study, we have used three rare nearly-simultaneous observations of
1E{\thinspace}1740.71942 by both XMM-Newton and INTEGRAL satellites to
combine spectra from four different imaging instruments with no data gaps, and
we successfully applied the Comptonization scenario to explain the broadband
X-ray spectra of this source in the low/hard state. For two of the three
observations, our analysis also shows that, models including Compton reflection
can adequately fit the data, in agreement with previous reports. We show that
the observations can also be modeled by a more detailed Comptonization scheme.
Furthermore, we find the presence of an iron K-edge absorption feature in one
occasion, which confirms what had been previously observed by Suzaku. Our
broadband analysis of this limited sample shows a rich spectral variability in
1E{\thinspace}1740.72942 at the low/hard state, and we address the possible
causes of these variations. More simultaneous soft/hard X-ray observations of
this system and other black-hole binaries would be very helpful in constraining
the Comptonization scenario and shedding more light on the physics of these
systems.Comment: 6 pages, two figures, accepted for publication in A&
Short term X-ray rms variability of Cyg X-1
A linear dependence of the amplitude of broadband noise variability on flux
for GBHC and AGN has been recently shown by Uttley & McHardy (2001). We present
the long term evolution of this rms-flux-relation for Cyg X-1 as monitored from
1998-2002 with RXTE. We confirm the linear relationship in the hard state and
analyze the evolution of the correlation for the period of 1996-2002. In the
intermediate and the soft state, we find considerable deviations from the
otherwise linear relationship. A possible explanation for the rms-flux-relation
is a superposition of local mass accretion rate variations.Comment: 3 pages, 3 figures, Proceedings of the 4th Microquasar Workshop, eds.
Ph Durouchoux, Y. Fuchs and J. Rodriguez, published by the Center for Space
Physics: Kolkat
Broadband Suzaku observations of IGR J16207-5129
An analysis of IGR J16207-5129 is presented based on observations taken with
Suzaku. The data set represents ~80 ks of effective exposure time in a broad
energy range between 0.5 and 60 keV, including unprecedented spectral
sensitivity above 15 keV. The average source spectrum is well described by an
absorbed power law in which we measured a large intrinsic absorption of nH =
16.2(-1.1/+0.9)x10^22 /cm2. This confirms that IGR J16207-5129 belongs to the
class of absorbed HMXBs. We were able to constrain the cutoff energy at
19(-4/+8) keV which argues in favor of a neutron star as the primary. Our
observation includes an epoch in which the source count rate is compatible with
no flux suggesting a possible eclipse. We discuss the nature of this source in
light of these and of other recent results.Comment: 12 pages, 6 figures, accepted for publication in Ap
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