239 research outputs found
Effects of a nickel reactor liner and other reaction variables during supercritical water reformation of glycerin
The non-catalytic reformation of glycerin using supercritical water was conducted in a 400-mL tubular reactor constructed of Haynesʼ Alloy 230. The evaluated parameters for this thesis include water-to-glycerin molar ratios ranging from 3 to 24 and reactor temperatures ranging from 500⁰C to 700⁰C. In addition, experiments were performed using the Haynes\u27 Alloy 230 reactor both without a liner and with a Nickel 201 liner. Space time was maintained at approximately 100 seconds and the reactor pressure was kept constant at 24.1 MPa. The resultant effect on product gas composition and carbon gasification was determined. The product gases consisted of a mixture of hydrogen, carbon monoxide, carbon dioxide, methane and ethane. It was found that the greatest gas yields of hydrogen were produced at higher temperatures using more dilute glycerin solutions. Increasing the water-to-glycerin ratio and increasing temperature, up to approximately 13.5 and 600⁰C respectively, increased the extent of carbon gasification. Once these values were reached, 100% carbon gasification percentages were achieved. The reactor liner made of nickel was found to have a positive catalytic effect on both the reformation and water gas shift reaction. The experiments conducted with the liners produced higher carbon dioxide and hydrogen yields. The greatest hydrogen and carbon dioxide yields were obtained at 24 water-to-glycerin ratio and a temperature of700⁰C using a reactor liner. In this thesis, the effects of water-to-glycerin ratios, temperature, and a reactor liner upon supercritical water reformation of glycerin are revealed based on the experimental data --Abstract, page iii
Theorizing Development of Parasocial Engagement
The article proposes a theoretical model of the development of parasocial relationships (PSRs) building on Knapp’s model of relationship development. Through synthesis of research across disciplines, the model conceptualizes the relational goals and parasocial interactions (PSIs) specific to the PSR. The model identifies variables that predict engagement at that level, describes the stage’s outcomes/effects, and considers the utility of existing measures to assess these stages. The conceptualization of PSRs as a dynamic process rather than intensity of a monolithic experience offers new directions worthy of empirical examination
Death and Communal Mass-Mourning: Vin Diesel and the Remembrance of Paul Walker
This article examines Vin Diesel’s use of his public Facebook Page to mourn the loss of his friend and co-actor Paul Walker in the period from 2013-2015. It discusses how Vin Diesel performed his grief and how his mourning process was communally reflected and repeated by both Vin Diesel and Walker fans, who used Vin Diesel’s page to share and verbalise their own feelings of loss in a both public and safe space. An analysis of Vin Diesel’s own status updates and 1800 comments reacting to three popular status updates related to the death of Paul Walk posted over the course of more than a year show that commentary was used to make condolences to both Vin Diesel and Walker’s familes and to affectively express the users’ immediate feelings, both verbally and through the use of emojis. However, over time, both the form and intensity of expression of both Vin Diesel and his followers changed, pointing to the need to further study celebrity mourning processes on social media over extended periods of time
The geometry of the magnetic field in the central molecular zone measured by PILOT
We present the first far infrared (FIR) dust emission polarization map covering the full extent of Milky Way’s central molecular zone (CMZ). The data, obtained with the PILOT balloon-borne experiment, covers the Galactic center region − 2° < ℓ < 2°, − 4° < b < 3° at a wavelength of 240 μm and an angular resolution of 2.2′. From our measured dust polarization angles, we infer a magnetic field orientation projected onto the plane of the sky (POS) that is remarkably ordered over the full extent of the CMZ, with an average tilt angle of ≃22° clockwise with respect to the Galactic plane. Our results confirm previous claims that the field traced by dust polarized emission is oriented nearly orthogonally to the field traced by GHz radio synchrotron emission in the Galactic center region. The observed field structure is globally compatible with the latest Planck polarization data at 353 and 217 GHz. Upon subtraction of the extended emission in our data, the mean field orientation that we obtain shows good agreement with the mean field orientation measured at higher angular resolution by the JCMT within the 20 and 50 km s−1 molecular clouds. We find no evidence that the magnetic field orientation is related to the 100 pc twisted ring structure within the CMZ. The low polarization fraction in the Galactic center region measured with Planck at 353 GHz combined with a highly ordered projected field orientation is unusual. This feature actually extends to the whole inner Galactic plane. We propose that it could be caused by the increased number of turbulent cells for the long lines of sight towards the inner Galactic plane or to dust properties specific to the inner regions of the Galaxy. Assuming equipartition between magnetic pressure and ram pressure, we obtain magnetic field strength estimates of the order of 1 mG for several CMZ molecular clouds
LiteBIRD Science Goals and Forecasts. A Case Study of the Origin of Primordial Gravitational Waves using Large-Scale CMB Polarization
We study the possibility of using the satellite -mode survey to
constrain models of inflation producing specific features in CMB angular power
spectra. We explore a particular model example, i.e. spectator axion-SU(2)
gauge field inflation. This model can source parity-violating gravitational
waves from the amplification of gauge field fluctuations driven by a
pseudoscalar "axionlike" field, rolling for a few e-folds during inflation. The
sourced gravitational waves can exceed the vacuum contribution at reionization
bump scales by about an order of magnitude and can be comparable to the vacuum
contribution at recombination bump scales. We argue that a satellite mission
with full sky coverage and access to the reionization bump scales is necessary
to understand the origin of the primordial gravitational wave signal and
distinguish among two production mechanisms: quantum vacuum fluctuations of
spacetime and matter sources during inflation. We present the expected
constraints on model parameters from satellite simulations, which
complement and expand previous studies in the literature. We find that
will be able to exclude with high significance standard single-field
slow-roll models, such as the Starobinsky model, if the true model is the
axion-SU(2) model with a feature at CMB scales. We further investigate the
possibility of using the parity-violating signature of the model, such as the
and angular power spectra, to disentangle it from the standard
single-field slow-roll scenario. We find that most of the discriminating power
of will reside in angular power spectra rather than in and
correlations.Comment: 22 pages, 13 figures. Submitted to JCA
Belle II Vertex Detector Performance
The Belle II experiment at the SuperKEKB accelerator (KEK, Tsukuba, Japan) collected its first e+e− collision data in the spring 2019. The aim of accumulating a 50 times larger data sample than Belle at KEKB, a first generation B-Factory, presents substantial challenges to both the collider and the detector, requiring not only state-of-the-art hardware, but also modern software algorithms for tracking and alignment.
The broad physics program requires excellent performance of the vertex detector, which is composed of two layers of DEPFET pixels and four layers of double sided-strip sensors. In this contribution, an overview of the vertex detector of Belle II and our methods to ensure its optimal performance, are described, and the first results and experiences from the first physics run are presented
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