89 research outputs found
Characterization of materials used in the manufacture of ceramic tile with incorporation of ornamental rock waste
The production of ceramic tiles, such as tiles, has a great environmental impact, either in
the extraction of natural raw materials or gas emissions in the burning stages. The use of industrial
solid waste in ceramic materials can contribute to the reduction of these impacts, according to the
characteristics of solid waste and its interaction with ceramic materials in the processing steps. Thus,
this study aimed to characterize the materials needed to make a ceramic tile with incorporation of
ornamental rock waste (ORW), thus evaluating its main characteristics regarding the feasibility of this
incorporation. The physical characterization of the clays used in the production of ceramic artifacts
was performed, and for the waste the mineralogical analyzes were performed, through x-ray diffraction
(XRD), microstructure analysis from confocal optical microscopy, after sintering the prototypes and
chemical analysis by X-ray spectroscopy (EDX). Soon after the raw materials went through the step
of conformation and preparation of the prismatic specimens by the process of extrusion of the ceramic
mass, with an incorporation of the ORW in 0% and 15% of the ceramic mass, for its subsequent The
prototypes were sintered at three different temperatures (850 °C, 950 °C and 1,050 °C). The specimens
were submitted to technological tests of mechanical resistance, water absorption, firing shrinkage and
porosity to evaluate the incorporation viability. The results indicated the presence of quartz particles
in all raw materials, and also that the clays of the study region are predominantly kaolinitic. The
presence of these materials in the ceramic masses directly influences the micrographs, because they
result in the formation of liquid phase, inert particles that can turn the site into a stress concentration
point and when incorporated in the ORW the specimens met the technical specifications of the
Brazilian standard for application on ceramic tiles. The results found in the technological tests carried
out, that the incorporation of 15% of ornamental rock waste in both clays did not affect the tile
properties, indicating the feasibility of incorporating this waste in civil construction, minimizing the
impacts generated
Spiranthes vernalis Engelm. & A. Gray
https://thekeep.eiu.edu/herbarium_specimens_byname/21408/thumbnail.jp
Neutrino-driven wind simulations and nucleosynthesis of heavy elements
Neutrino-driven winds, which follow core-collapse supernova explosions,
present a fascinating nuclear astrophysics problem that requires understanding
advanced astrophysics simulations, the properties of matter and neutrino
interactions under extreme conditions, the structure and reactions of exotic
nuclei, and comparisons against forefront astronomical observations. The
neutrino-driven wind has attracted vast attention over the last 20 years as it
was suggested to be a candidate for the astrophysics site where half of the
heavy elements are produced via the r-process. In this review, we summarize our
present understanding of neutrino-driven winds from the dynamical and
nucleosynthesis perspectives. Rapid progress has been made during recent years
in understanding the wind with improved simulations and better micro physics.
The current status of the fields is that hydrodynamical simulations do not
reach the extreme conditions necessary for the r-process and the proton or
neutron richness of the wind remains to be investigated in more detail.
However, nucleosynthesis studies and observations point already to
neutrino-driven winds to explain the origin of lighter heavy elements, such as
Sr, Y, Zr.Comment: Submitted to: J. Phys. G: Nucl. Phy
AWAKE, the advanced proton driven plasma wakefield acceleration experiment at CERN
The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world׳s first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms ~12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy (~15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented
Faculty accountability and faculty workload: A preliminary cost analysis of their relationship as revealed by PhD productivity
General concerns for faculty accountability are examined in the context of faculty workload and costs. Graduating a PhD student is used as the unit for analysis. The unit is compared to instructional productivity. The data came from a 10-year interval at a major graduate university. Six liberal arts departments with a 225-member faculty provide the PhD output and workload information. Work equivalents are determined from institutional and faculty self-reports. Graduating a PhD is found to be equivalent to one-third of a full workload. Implications are given for comparisons between programs within a university and between types of institutions in the larger system of higher education. Concerns also emerge for improved personnel practices with respect to faculty work assignments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43583/1/11162_2004_Article_BF00991561.pd
Inhibition of Enterovirus 71 (EV-71) Infections by a Novel Antiviral Peptide Derived from EV-71 Capsid Protein VP1
Enterovirus 71 (EV-71) is the main causative agent of hand, foot and mouth disease (HFMD). In recent years, EV-71 infections were reported to cause high fatalities and severe neurological complications in Asia. Currently, no effective antiviral or vaccine is available to treat or prevent EV-71 infection. In this study, we have discovered a synthetic peptide which could be developed as a potential antiviral for inhibition of EV-71. Ninety five synthetic peptides (15-mers) overlapping the entire EV-71 capsid protein, VP1, were chemically synthesized and tested for antiviral properties against EV-71 in human Rhabdomyosarcoma (RD) cells. One peptide, SP40, was found to significantly reduce cytopathic effects of all representative EV-71 strains from genotypes A, B and C tested, with IC50 values ranging from 6–9.3 µM in RD cells. The in vitro inhibitory effect of SP40 exhibited a dose dependent concentration corresponding to a decrease in infectious viral particles, total viral RNA and the levels of VP1 protein. The antiviral activity of SP40 peptide was not restricted to a specific cell line as inhibition of EV-71 was observed in RD, HeLa, HT-29 and Vero cells. Besides inhibition of EV-71, it also had antiviral activities against CV-A16 and poliovirus type 1 in cell culture. Mechanism of action studies suggested that the SP40 peptide was not virucidal but was able to block viral attachment to the RD cells. Substitutions of arginine and lysine residues with alanine in the SP40 peptide at positions R3A, R4A, K5A and R13A were found to significantly decrease antiviral activities, implying the importance of positively charged amino acids for the antiviral activities. The data demonstrated the potential and feasibility of SP40 as a broad spectrum antiviral agent against EV-71
Women and power: a theoretical approach using the example of copreneurial businesses
Despite the gradual recognition of strategic issues related to the integration of women into the economy, female entrepreneurship continues to receive little attention. Family business research attributes this situation to a lack of recognition given to the (decisive) role of women in these organizations. However, there is one type of family governance that formally acknowledges the man/woman combination: the copreneurial company. Copreneurs are couples who run a business together. This theoretical article highlights the role of women in the copreneurial context by distinguishing between formal and informal power- the latter being primarily held by women, but which is no less influential. The distribution of power reduces opposition costs between partners and the social costs of non-compliance, and improves the clarity of the entrepreneurial structure. Moreover, it increases satisfaction and a feeling of equality between the partners. These results can be generalized and shed light on the role of women in other entrepreneurial and social contexts. This article is published as part as part of a collection on the role of women in management and business
- …