783 research outputs found
On The Influence Of Indigenous Languages On Brazilian Portuguese
[No abstract available]30SpecialIssue44344
Tire Rubber-cement Composites: Effect Of Slag On Properties [compósites De Cimento - Borracha De Pneus: Efeito Da Escória Nas Propriedades]
Tire rubber-cement composites prepared with type I and three slag-modified cements were studied. Flexural strength, water sorption and resistance to acid attack of specimens were investigated. A decrease in modulus of rupture (MOR) is observed for all specimens containing rubber, when compared with specimens without rubber (controls). The MOR increases with the increase of the hydraulic activity of the slag upon undistinguishable from specimens prepared with type I cement. This behavior is observed for all slag-cements pastes and for mortars control specimens. For mortar specimens with rubber the MOR is independent of the cement type used. A reduction in water sorption is observed for control and with-rubber mortar specimens prepared with all slag-cements, when compared to type I cement. For mortar specimens with rubber, the lower the basicity of the slag, the lesser the water sorption of the composites. These results denote lower porosity and consequently better rubber-matrix adhesion for these specimens. Also, a smaller rate of water sorption is observed for specimens with rubber, particularly for specimens prepared with the less basic slag cements, when comparing with the controls. Results of acid attack to the slag modified mortars indicate that specimen susceptibility is governed not only by microstructural aspects, like porosity and permeability, but also by chemical aspects as the difference in alkali content or the amount of unreacted slag in the specimens.52324283292Lee, B.I., Burnett, L., Miller, T., Postage, P., Cuneo, J., (1993) J. Mater. Sci. Lett, 12, p. 967I. B. Topçu, Gem. Conor. Res. 25 (1995) 304Raghavan, D., Huynh, H., Ferraris, C.F., (1998) J. Mater. Sci, 33, p. 1745Bignozzi, M.C., Saccani, A., Sandrolini, F., (2000) Composites A, 31, p. 97Raghavan, D., (2000) J. Appl. Polym. Sci, 77, p. 934M. Nehdi, A. Khan, Cem. Concr. Aggregates 23 (2001) 3Hernandez-Olivares, F., Barluenga, G., Bollati, M., Witoszek, B., (2002) Cem. Concr. Res, 32, p. 1587N. Segre, I. Joekes, Gem. Concr. Res. 30 (2000) 1421(2001) Lea's Chemistry of Cement and Concrete, , P. C. Hewlett Ed, 4 th Ed, Butterworth Heinemann, OxfordMyers, D., (1999) Surfaces, Interfaces, and Colloids-Principles and Applications, , 2nd Ed, John Wiley & Sons, New YorkBikerman, J.J., (1961) The Science of Adhesive Joints, , Academic Press, New YorkMindess, S., Interfaces in concrete (1989) Materials Science of Concrete I, p. 163. , J.P. Skalny Ed, The Am. Ceram. Soc, Westerville, OHLuke, K., Glasser, F.P., (1987) Cem. Concr. Res, 17, p. 273M. A. Cincotto, A. F. Battagin, V. Agopyan, Bulletin 65, Ed.: Institute for Technological Research, IPT, S. Paulo, Brazil (1992)ASTM C150 - Standard specification for Portland cement, American Society for Testing and Materials (1995)- Standard specification for blended hydraulic cements (1994), ASTM C595, American Society for Testing and MaterialsMindess, S., Young, J.F., (1981) Concrete, , Prentice-Hall, Englewood Cliffs, New JerseyMehta, P.K., Monteiro, P.J.M., (1993) Concrete: Structure, Properties and Materials, , 2nd Ed, Prentice-Hall, Englewood Cliffs, New JerseyGriffith, A.A., (1920) Phil. Trans. R. Soc. Lond. A, 221, p. 163Birchall, J.D., Howard, A.J., Kendall, K., (1981) Nature, 289, p. 388Martins, M.A., Mattoso, L.H.C., (2004) J. Appl. Polym. Sci, 91, p. 670Lumley, J.S., Gollop, R.S., Moir, G.K., Taylor, H.F.W., (1996) Cem. Concr. Res, 26, p. 139Glasser, F.P., Chemical, mineralogical, and microstructural changes occurring in hydrates slag-cement blends (1991) Materials Science of Concrete II, p. 41. , J. P. Skalny, S. Mindess Eds, The Am. Ceram. Soc, Westerville, OHSegre, N., Monteiro, P.J.M., Sposito, G., (2002) J. Colloid Interface Sci, 248, p. 521Falcon, P., Adenot, F., Jacquinot, J.F., Petit, J.C., Cabrillac, R., Jordas, M., (1998) Cem. Conor. Res, 28, p. 847Israel, D., Macphee, D.E., Lachowski, E.E., (1997) J. Mater. Sci, 32, p. 4109Chandra, S., (1988) Cem. Conor. Res, 18, p. 193Zivica, V., Bajza, A., (2001) Constr. Build. Mater, 15, p. 331Pavlik, V., (1994) Cem. Conor. Res, 24, pp. 551-562Debelie, N., Verselder, H.J., Deblaere, B., Vannieuwenburg, D., Verschoore, R., (1996) Cem. Conor. Res, 26, p. 1717Shi, C., Stegemann, J.A., (2000) Cem. Conor. Res, 30, p. 803Zivica, V., Bajza, A., (2002) Constr. Build. Mater, 16, p. 215Deceukelaire, L., (1992) Cem. Conor. Res, 22, p. 903A. Macias, S. Goni, J. Madrid, Cem. Conor. Res. 29 (1999) 2005J. Hill, E. A. Byars, J. H. Sharp, C. J. Lynsdale, J. C. Cripps, Q. Zhou, Cem. Conor. Compos. 25 (2003) 997Hobbs, D.W., (2001) Int. Mater. Rev, 46, p. 11
Differential gene expression and immunolocalization of platelet-derived growth factors and their receptors in caprine ovaries
AbstractThis study evaluated the messenger RNA (mRNA) expression and immunolocalization of all members of the platelet-derived growth factor (PDGF) family in caprine ovaries by quantitative PCR and immunohistochemistry, respectively. Detectable levels of PDGF-A mRNA were not observed in primordial follicles. Higher levels of PDGF-B mRNA were observed in primary follicles than in primordial follicles (P < 0.05). PDGF-D mRNA levels were higher in secondary follicles than in the other preantral follicle categories (P < 0.05). PDGF-B mRNA expression was higher than PDGF-C mRNA expression in primary follicles (P < 0.05). In antral follicles, PDGF-A mRNA expression was higher in cumulus-oocyte complexes (COCs) from small antral follicles than in those from large antral follicles and their respective granulosa/theca (GT) cells (P < 0.05). Furthermore, in COCs from small and large antral follicles, PDGF-A mRNA expression was higher than that of the other PDGF isoforms (P < 0.05). The mRNA levels of PDGF-B and PDGF-D and PDGFR-α and PDGFR-β were higher in GT cells from large antral follicles than in GT cells from small antral follicles and in their respective COCs (P < 0.05). In COCs and GT cells from small antral follicles, the mRNA levels of PDGFR-α were higher than those of PDGFR-β (P < 0.05). All proteins were observed in the cytoplasm of oocytes from all follicular categories. In granulosa cells, all PDGFs and PDGFR-β were detected from starting at the secondary stage, and in theca cells, all proteins, except PDGF-C, were detected starting at the antral stage. In conclusion, PDGF and its receptors are differentially expressed in the oocytes and ovarian cells according to the stage of follicular development, suggesting their role in the regulation of folliculogenesis in goats
Effect of metformin therapy and dietary supplements on semen parameters in hyperinsulinaemic males
Previous reports indicated that hyperinsulinaemic men may exhibit a higher
percentage of poorly compacted DNA in their spermatozoa and less success in
an IVF programme (Andrologia, 45, 2003, 18; Andrologia, 2014, doi: 10.1111/
and.12227). The aim of this study was to investigate the effect of metformin
(Glucophage ) and antioxidant treatment (StaminoGro ) on the semen parameters
of hyperinsulinaemic men. Nineteen hyperinsulinaemic male patients were
treated for 3 months with metformin alone (Group A), and fifteen patients used
metformin in combination with the nutritional supplement (Group B). Combined
data of the two groups (pre- and post-treatment) differ significantly
regarding sperm morphology (P = 0.0003) and CMA3 (P < 0.0001) values. The
improvement in sperm morphology after treatment was similar for the two
respective groups (P < 0.05). The morphological normal sperm forms increased
from the mean percentage of 3.9 to 5.5% and from 4.2 to 5.5% for Group A
and B respectively. Where a combination of metformin and the supplement
were used (Group B), the combination treatment proved to be superior in
obtaining enhanced chromatin packaging quality although not statistically significant
(P = 0.5929) when compared with the metformin (Group A) group.
The chromatin packaging quality in Group B improved with 10% while the
improvement in Group A was approximately 8.3%. Therefore, infertile hyperinsulinaemic
men can benefit from metformin treatment and should be advised
on the use of nutritional supplements with antioxidant properties.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1439-02722016-11-30hb2016Clinical Epidemiolog
Simulation models for tankless gas water heaters
There is a growing concern about to the scarceness of natural resources and the emissions problematic. Water heating is a relevant part of a household’s energy use, and tankless gas water heaters (TGWH) are widely used. There are design and engineering challenges to develop more efficient devices, with lower emissions of pollutant gases and providing comfort improvements from the user point of view.
The main objective of the present work is to provide mathematical models to evaluate and support the development of different TGWH configurations. By simulation, different hardware configurations and advanced control strategies can be tested and optimized regarding energy saving, reducing of harmful environmental emissions and increase of comfort indices by reducing temperature undershoots and overshoots.
The TGWH individual components are modelled, laboratory tests are performed and the heat cell is parametrized with experimental data. Configurations with and without bypass function are performed for several water flow rates and setpoint temperature patterns in open loop and with feed-forward control.publishe
Historical separation and present-day structure of common dolphinfish (Coryphaena hippurus) populations in the Atlantic Ocean and Mediterranean Sea
The common dolphinfish (Coryphaena hippurus) is an epipelagic, mid-trophic level, highly migratory species distributed throughout the
world’s tropical and subtropical oceans in waters greater than 20C. Life-history variables, migratory behaviour, and genetic markers have
been used to define major stocks in the central Atlantic Ocean and Mediterranean Sea. Here, we used the mitochondrial DNA gene NADH
subunit 1 (688 bp) to test for differences between population groups. A total of 103 haplotypes were detected among 203 fish. Gene diversities in samples were large and similar among populations (mean h ¼ 0.932; range 0.894–0.987), but nucleotide diversities varied widely among
samples (range p ¼ 0.004–0.034) and appear to reflect population histories. Principal component analysis revealed two large populations
groups, and the analysis of molecular variation and pairwise values of UST resolved population structure within these groups. Populations in
the eastern Atlantic and Mediterranean showed the largest amounts of divergence from one another (UCT ¼ 0.331). Adult movement and
biophysical barriers to larval dispersal may explain contemporary differences between stocks, but the divergent populations in the Mediterranean Sea are likely due to isolations by cold temperature barriers during Pleistocene glaciations. The geographically large stock
groupings require international cooperation in the harvest management and conservation of local dolphinfish populations
The T2K ND280 Off-Axis Pi-Zero Detector
The Pi-Zero detector (P{\O}D) is one of the subdetectors that makes up the
off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino
experiment. The primary goal for the P{\O}D is to measure the relevant cross
sections for neutrino interactions that generate pi-zero's, especially the
cross section for neutral current pi-zero interactions, which are one of the
dominant sources of background to the electron neutrino appearance signal in
T2K. The P{\O}D is composed of layers of plastic scintillator alternating with
water bags and brass sheets or lead sheets and is one of the first detectors to
use Multi-Pixel Photon Counters (MPPCs) on a large scale.Comment: 17 pages, submitted to NIM
An Inflationary Scenario Taking into Account of Possible Dark Energy Effects in the Early Universe
We investigate the possible effect of cosmological-constant type dark energy
during the inflation period of the early universe. This is accommodated by a
new dispersion relation in de Sitter space. The modified inflation model of a
minimally-coupled scalar field is still able to yield an observation-compatible
scale-invariant primordial spectrum, simultaneously having potential to
generate a spectrum with lower power at large scales. A qualitative match to
the WMAP 7-year data is presented. We obtain an of the same
order of that in the -CDM model. Possible relations between the de
Sitter scenario and the Doubly Special Relativity(DSR) are also discussed.Comment: 17 pages, 3 figuire
Hubble expansion and structure formation in the "running FLRW model" of the cosmic evolution
A new class of FLRW cosmological models with time-evolving fundamental
parameters should emerge naturally from a description of the expansion of the
universe based on the first principles of quantum field theory and string
theory. Within this general paradigm, one expects that both the gravitational
Newton's coupling, G, and the cosmological term, Lambda, should not be strictly
constant but appear rather as smooth functions of the Hubble rate. This
scenario ("running FLRW model") predicts, in a natural way, the existence of
dynamical dark energy without invoking the participation of extraneous scalar
fields. In this paper, we perform a detailed study of these models in the light
of the latest cosmological data, which serves to illustrate the
phenomenological viability of the new dark energy paradigm as a serious
alternative to the traditional scalar field approaches. By performing a joint
likelihood analysis of the recent SNIa data, the CMB shift parameter, and the
BAOs traced by the Sloan Digital Sky Survey, we put tight constraints on the
main cosmological parameters. Furthermore, we derive the theoretically
predicted dark-matter halo mass function and the corresponding redshift
distribution of cluster-size halos for the "running" models studied. Despite
the fact that these models closely reproduce the standard LCDM Hubble
expansion, their normalization of the perturbation's power-spectrum varies,
imposing, in many cases, a significantly different cluster-size halo redshift
distribution. This fact indicates that it should be relatively easy to
distinguish between the "running" models and the LCDM cosmology using realistic
future X-ray and Sunyaev-Zeldovich cluster surveys.Comment: Version published in JCAP 08 (2011) 007: 1+41 pages, 6 Figures, 1
Table. Typos corrected. Extended discussion on the computation of the
linearly extrapolated density threshold above which structures collapse in
time-varying vacuum models. One appendix, a few references and one figure
adde
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