1,466 research outputs found
Studies on the production of calcium carbide in a 400 kVA soderberg electrode furnace
No full textA prototype 400 kVA arc furnace using graphite electrodes has been retrofitted with soderberg self-baking electrodes, and the present paper describes the features of the retrofitted arc furnace facility and the results of the experiments which establish the advantages of self-baking electrode
Relativistic supernovae have shorter-lived central engines or more extended progenitors: the case of SN 2012ap
No full textDeep, late-time X-ray observations of the relativistic, engine-driven, type Ic SN 2012ap allow us to probe the nearby environment of the explosion and reveal the unique properties of relativistic supernova explosions (SNe). We find that on a local scale of ~0.01 pc the environment was shaped directly by the evolution of the progenitor
star with a pre-explosion mass-loss rate of ̇ M <5 × 10−6Msun/yr, in line with gamma-ray bursts (GRBs) and the other relativistic SN 2009bb. Like sub-energetic GRBs, SN 2012ap is characterized by a bright radio emission and evidence for mildly relativistic ejecta. However, its late-time (δt ≈ 20 days) X-ray emission is ~100 times fainter than the faintest sub-energetic GRB at the same epoch, with no evidence for late-time central engine activity. These results support theoretical proposals that link relativistic SNe like 2009bb and 2012ap with the weakest observed engine-driven explosions, where the jet barely fails to break out. Furthermore, our observations demonstrate that the difference between relativistic SNe and sub-energetic GRBs is intrinsic and not due to line-of-sight effects. This phenomenology can either be due to an intrinsically shorter-lived engine or to a more extended progenitor in relativistic SNe
Aerodynamics Of Turbines
No full textPaperPg. 90-104.The transformation between work and other forms of energy is accomplished in turbomachinery. The ability of a turbine to produce work when handling a compressible fluid and when taking either its axial or radial configuration is presented for the user of the equipment rather than the designer or research worker. The basic conservation principles of mass, linear momentum, energy, and angular momentum in their steady, one-dimensional form are summarized; the figures of merit of turbine stage performance including efficiency, reaction and reheat are defined and interrelated. Correlation of losses with performance parameters is presented first for the over-all stage. Then the Soderberg correlation is provided for handling the axial stage, component by component, and the Benson correlation is introduced for use with a radial stage. An example lists all of the parameters and flow conditions which can be predicted for a prospective design or evaluated for an existing unit of hardware
BLUEAGE, Blue Energy for a Green Europe, Strategic Study for the development of small hydro power in Europe
No full textFinal Report of an Altener project, evaluating the potential of Hydropower in Europ
Developments in the production of soderberg paste for electrodes in ferro alloy furnaces
No full textUsing raw petroleum coke as raw-material, NML has devel-oped a dense carbon aggregate as a substitute for gas calcined anthracite. This dense carbon aggregate has been used for making soderberg paste, the properties of which have been studied and compared with a Norwegian and two indigenous pastes. The suitability of this material has been tested on a commercial scale in ferro alloy and pig iron furnaces.
Attempts also have been made to produce dense carbon aggregate by partial replacement of petroleum coke with low ash coal and the study of its properties have been described in this paper
Detection of human cytomegalovirus in synovial neutrophils obtained from patients with rheumatoid arthritis
No full textObjectives: To examine whether signs of an active human cytomegalovirus (HCMV) infection are present in affected joints of patients with rheumatoid arthritis (RA). Method: Polymorphonuclear leucocytes (PMNLs) were obtained from synovial fluid (SF) of 17 RA patients and were analysed for HCMV-pp65 and HCMV-immediate early (IE) proteins using the antigenemia assay. Peripheral blood (PB) and SF obtained from these 17 patients and from 17 additional RA patients (n = 34) were tested for HCMV-IE and pp150 DNA with Taqman polymerase chain reaction. Plasma samples from the patients were analysed for HCMV-immunoglobulin M (IgM) and immunoglobulin G (IgG) by enzyme-linked immunosorbent assay and compared to 71 healthy gender-matched blood donors. Results: HCMV-pp65 protein was detected in 65% of synovial PMNL samples, but in only 18% of PMNLs from PB. In contrast, HCMV IE protein was not found in any of the analysed PMNL samples. On the DNA level, HCMV-IE and pp150 DNA was detected in SF of 13/32 (41%) and 14/23 (61%) of RA patients, respectively. HCMV-IE and pp150 DNA was also found in 24/33 (73%) and in 16/24 (67%) of PB samples obtained from RA patients, respectively. HCMV IgG seroprevalence was 76% in RA patients as well as in healthy controls, while only one RA patient was positive for specific IgM. Conclusions: HCMV pp65 antigen was found in PMNLs from SF of RA patients, indicating an active infection in the affected joint. Future studies are needed to determine whether HCMV infection can aggravate the inflammatory process in these patients
Ground-State Structural Disorder and Excited-State Symmetry Breaking in a Quadrupolar Molecule
No full textThe
influence of torsional disorder around the ethynyl π-bridges
of a linear D−π–A−π–D molecule
on the nature of its S1 excited state was investigated
using ultrafast time-resolved infrared spectroscopy. By tuning the
pump wavelength throughout the S1 ← S0 absorption band, subpopulations with different extents of asymmetry
could be excited. In nonpolar solvents, the equilibrated S1 state is symmetric and quadrupolar independently of the initial
degree of distortion. Photoexcitation of distorted molecules is followed
by planarization and symmetrization of the S1 state. Excited-state
symmetry breaking is only observed in polar environments, where the
equilibrated S1 state has a strong dipolar character. However,
neither the extent nor the rate of symmetry breaking are enhanced
in an initially distorted molecule. They are only determined by the
polarity and the dynamic properties of the solvent
The autonomous adaptation of US homes to changing temperatures
No full textLittle is known about how households adapt to climate change. Previous research has focused on geographical differences in fuel choice and air conditioning. Using a twenty-eight-year panel of homes, we conducted the first longitudinal analysis of eight categories of adaptations and their impact on electricity, gas, and water expenditures. Exposure to cold or warm days correlates with increased spending on doors, windows, equipment, insulation, energy, and water. Our findings suggest cooling costs will rise, offset by lower heating costs. We predict a significant increase in electricity and water use during summer, leading to seasonal utility adjustments.Full Tex
Core-collapse Supernova Progenitors in the Era of Untargeted Transient Searches
No full textCore-collapse supernovae (SNe) are the highly energetic explosions of massive stars (> 8 solar masses) that are pervasive in their influence throughout astrophysics. They are the phenomenon with primary responsibility for enriching the universe with many of the heavy elements (like carbon and oxygen) that are needed for life, provide a critical feedback pressure which helps to shape the galaxies that host them, and are the likely formation mechanism for stellar mass black holes. In the past decade, the study of these explosions has been revolutionized by the advent of wide field, untargeted transient searches like Pan-STARRS1 (PS1). These new searches permit the discovery of SNe at unprecedented rates, and absent of many of the selection effects that have enforced biases on past, targeted transient searches. This thesis presents a broad survey of core-collapse SN phenomenology exhibited in the discoveries of untargeted searches, and statistically quantifies population properties of these explosions that link them to distinct classes of progenitor stars. Through studies of the host galaxy and explosion properties of extreme PS1-discovered events, and controlled samples of specific classes of core-collapse objects, we constrain the effect of progenitor star chemical composition (metallicity) on their eventual death states. We provide a new observational, photometric tool which lowers the cost of precisely and accurately measuring the metallicities of distant galaxies and supernova host environments. Moreover, we develop and apply a novel, multi-level Bayesian model for optical transient light curves which we apply to simultaneously interpret more than 20,000 PS1 images. This study illustrates how population-level modeling of data from large photometric surveys can yield improved physical inference on their progenitor stars through comparison to physical models. In the coming era, as next-generation facilities like the Large Synoptic Survey Telescope come online, the supernova discovery rate will accelerate, far outpacing the community's capacity for detailed individual observational follow-up. New observational and statistical tools like those presented here will be critical to enable the next generation of studies in supernova astrophysics.Astronom
sj-docx-1-psr-10.1177_10888683241228328 – Supplemental material for Power to Detect What? Considerations for Planning and Evaluating Sample Size
No full textSupplemental material, sj-docx-1-psr-10.1177_10888683241228328 for Power to Detect What? Considerations for Planning and Evaluating Sample Size by Roger Giner-Sorolla, Amanda K. Montoya, Alan Reifman, Tom Carpenter, Neil A. Lewis, Christopher L. Aberson, Dries H. Bostyn, Beverly G. Conrique, Brandon W. Ng, Alexander M. Schoemann and Courtney Soderberg in Personality and Social Psychology Review</p
- …
