990 resultados para Aço ASTM A285 Gr C
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Resumen basado en el de la publicaci??n
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Sub-Saharan Africa in general and Ghana in particular, missed out on the Green revolution. Efforts are being made to re-introduce the revolution, and this calls for more socio-economic research into the factors influencing the adoption of new technologies, hence, this study. The study sought to find out how socio-economic factors contribute to adoption of Green revolution technology in Ghana. The method of analysis involved a maximum likelihood estimation of a probit model. The proportion of Green revolution inputs was found to be greater for the following: households whose heads had formal education, households with higher levels of non-farm income, credit and labor supply as well as those living in urban centers. It is recommended that levels of complementary inputs such as credit, extension services and infrastructure are increased. Also, households must be encouraged to form farmer-groups as an important source of farm labor. Furthermore, the fundamental problems of illiteracy must be addressed through increasing the levels of formal and non-formal education; and the gap between the rural and urban centers must be bridged through infrastructural and rural development. However, care must be taken to ensure that small-scale farmers are not marginalized, in terms of access to these complementary inputs that go with effective adoption of new technology. With these policies well implemented, Ghana can catch up with her Asian counterparts in this re-introduction of the revolution.
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Jag har jämfört hur unga människor lyssnade på inspelad musik på 1970-talet med hur unga lyssnar idag. Jag har gjort en enkätundersökning där två grupper, en som är ung idag och en som var ung på 1970-talet, fått svara på frågor om sitt musiklyssnande. Enkäten har jag kompletterat med fyra intervjuer. Den stora skillnaden när det gäller förutsättningarna för lyssnandet, är övergången från analog till digital teknik. Idag lyssnar vi mer vid datorn eller i portabla medier som mp3-spelare eller mobiltelefoner. På 1970-talet var man mer bunden till stationära anläggningar som stereoanläggningen eller radion. Teknikskiftet har också påverkat hur man lyssnar. Förr lyssnade man oftare tillsammans. Idag har det fysiska lyssnandet individualiserats. Den sociala interaktionen har i hög grad flyttat ut i cyberrymden: Man byter spotifylistor, man tipsar om klipp på youtube, man delar med sig av sin egenproducerade musik på myspace osv. Lars Lilliestam använder begreppet musikantropologi för att beskriva studiet av musik som en social aktivitet. Möjligheten att välja ur ett enormt utbud och sätta ihop sina egna spellistor har gett lyssnaren större kontroll över sitt lyssnande. De portabla medierna innebär också en möjlighet till effektivt tidsutnyttjande; man tar med sig musiken samtidigt som man gör något annat. Marie Strand Skånland har undersökt hur mp3-spelare används i vardagen och kommit fram till att musik används som en resurs. Lyssnande på personligt utvald musik, i form av spellistor, kan ge en känsla av kontroll över sig själv, omgivningen och över andra. Man stänger in sig i sin egen ljudbubbla.Lyssnarna anser att ljudkvaliteten har stor betydelse för musikupplevelsen. Men åsikterna går isär, både om vad som är bra ljudkvalitet och om vad som är en bra musikupplevelse.
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São apresentados os resultados dos estudos petrográfico e geoquímico dos carvões da jazida de Chico Lomã, localizada no município de Santo Antônio da Patrulha, no nordeste do Rio Grande da Sul, situada entre as jazidas de Morungava (limite oeste) e Santa Terezinha (limite leste). Na sondagem estudada - 02-TG-88-RS - foram identificadas 7 camadas e 5 leitos de carvão. Entre estes, apenas as camadas E e F apresentam suficiente extensão lateral para serem consideradas economicamente exploráveis. Os carvões são ricos em matéria mineral, constituída, principalmente, de argila. O grupo maceral mais freqüente é o da vitrinita. No que diz respeito aos microlitotipos, ocorre, em geral, o predomínio de carbominerita. Foram identificadas 3 associações de microlitotipos, determinando a existência das seguintes faciologias: ambiente telmático (predomínio de vitrita-clarita), limo-telmático (predomínio de carbargilita-vitrita) e límnico (predomínio de carbargilita-durita-trimacerita). Os carvões apresentam rank que varia de betuminoso alto volátil C/sub-betuminoso A a betuminoso alto volátil A (ASTM). A utilização tecnológica dos carvões das camadas E e F, na siderurgia, pode ser sugerida, mesmo considerando-se seu elevado teor em cinza, desde que sejam submetidos a processos de beneficiamento. Em relação aos argilo-minerais, constatou-se a presença de caolinita, aparentemente relacionada ao conteúdo da matéria orgânica, e do interestratificado ilita-montmorilonita, provavelmente de origem detrítica. Foram identificados 3 grupos de elementos traços : associados à fração orgânica (Co, Ge, Ni, V e Zr), elementos intermediários (Cr, Cu e Sr) e associados à fração inorgânica (B, Ba e Ga). Observou-se, também, que os elementos do primeiro grupo, de maneira geral, se enriquecem nos litotipos com maior conteúdo de vitrênio, ao contrário dos elementos do último grupo que tendem a se enriquecer no carvão fosco e nos folhelhos. Os estudos realizados indicam um paleoambiente de água doce, no qual, provavelmente, tenham ocorrido pequenas ingressões marinhas entre as fases de formação de turfa.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Characterization of the peptide content of venoms has a number of potential benefits for basic research, clinical diagnosis, development of new therapeutic agents, and production of antiserum. In order to analyze in detail the peptides and small proteins of crude samples, techniques such as chromatography and mass spectrometry have been employed. The present study describes the isolation, biochemical characterization, and sequence determination of a novel peptide, named Orpotrin from the venom of Potamotrygon gr. orbignyi. The natural peptide was shown to be effective in microcirculatory environment causing a strong vasoconstriction. The peptide was fully sequenced by de novo amino acid sequencing with mass spectrometry and identified as the novel peptide. Its amino acid sequence, HGGYKPTDK, aligns only with creatine kinase residues 97-105, but has no similarity to any bioactive peptide. Therefore, possible production of this peptide from creatine kinase by limited proteolysis is discussed. Taken together, the results indicate the usefulness of this single-step approach for low molecular mass compounds in complex samples such as venoms. (c) 2006 Elsevier B.V. All rights reserved.
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Stingrays of the family Potamotrygonidae are widespread throughout river systems of South America that drain into the Atlantic Ocean. Some species are endemic to the most extreme freshwater environment of the Brazil and cause frequent accidents to humans. The envenomation causes immediate, local, and intense pain, soft tissue edema, and a variable extent of bleeding. The present study was carried out in order to describe the principal biological and some biochemical properties of the Brazilian Potamotrygon fish venoms (Potamotrygon cf. scobina and P. gr. orbignyi). Both stingray venoms induced significant edematogenic and nociceptive responses in mice. Edematogenic and nociceptive responses were reduced when the venom was incubated at 37 or 56 degrees C. The results showed striking augments of leukocytes rolling and adherent cells to the endothelium of cremaster mice induced by both venoms. The data also presented that injection of both venoms induced necrosis, low level of proteolytic activity, without inducing haemorrhage. But when the venoms of both stingray species were injected together with their mucus secretion, the necrotizing activity was more vigorous. The present study provided in vivo evidence of toxic effects for P. cf. scobina and P. gr. orbignyi venoms. (c) 2006 Elsevier Ltd. All fights reserved.
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Pós-graduação em Engenharia Mecânica - FEIS
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Engenharia Mecânica - FEG
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The electromagnetic form factors of the proton are fundamental quantities sensitive to the distribution of charge and magnetization inside the proton. Precise knowledge of the form factors, in particular of the charge and magnetization radii provide strong tests for theory in the non-perturbative regime of QCD. However, the existing data at Q^2 below 1 (GeV/c)^2 are not precise enough for a hard test of theoretical predictions.rnrnFor a more precise determination of the form factors, within this work more than 1400 cross sections of the reaction H(e,e′)p were measured at the Mainz Microtron MAMI using the 3-spectrometer-facility of the A1-collaboration. The data were taken in three periods in the years 2006 and 2007 using beam energies of 180, 315, 450, 585, 720 and 855 MeV. They cover the Q^2 region from 0.004 to 1 (GeV/c)^2 with counting rate uncertainties below 0.2% for most of the data points. The relative luminosity of the measurements was determined using one of the spectrometers as a luminosity monitor. The overlapping acceptances of the measurements maximize the internal redundancy of the data and allow, together with several additions to the standard experimental setup, for tight control of systematic uncertainties.rnTo account for the radiative processes, an event generator was developed and implemented in the simulation package of the analysis software which works without peaking approximation by explicitly calculating the Bethe-Heitler and Born Feynman diagrams for each event.rnTo separate the form factors and to determine the radii, the data were analyzed by fitting a wide selection of form factor models directly to the measured cross sections. These fits also determined the absolute normalization of the different data subsets. The validity of this method was tested with extensive simulations. The results were compared to an extraction via the standard Rosenbluth technique.rnrnThe dip structure in G_E that was seen in the analysis of the previous world data shows up in a modified form. When compared to the standard-dipole form factor as a smooth curve, the extracted G_E exhibits a strong change of the slope around 0.1 (GeV/c)^2, and in the magnetic form factor a dip around 0.2 (GeV/c)^2 is found. This may be taken as indications for a pion cloud. For higher Q^2, the fits yield larger values for G_M than previous measurements, in agreement with form factor ratios from recent precise polarized measurements in the Q2 region up to 0.6 (GeV/c)^2.rnrnThe charge and magnetic rms radii are determined as rn⟨r_e⟩=0.879 ± 0.005(stat.) ± 0.004(syst.) ± 0.002(model) ± 0.004(group) fm,rn⟨r_m⟩=0.777 ± 0.013(stat.) ± 0.009(syst.) ± 0.005(model) ± 0.002(group) fm.rnThis charge radius is significantly larger than theoretical predictions and than the radius of the standard dipole. However, it is in agreement with earlier results measured at the Mainz linear accelerator and with determinations from Hydrogen Lamb shift measurements. The extracted magnetic radius is smaller than previous determinations and than the standard-dipole value.
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verf. von [Nathan] Epstein
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von Moritz Steckelmacher
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Current EU Directives force the Member States to assure by 2020 that 70% of the Construction and Demolition (C&D) waste is recovered instead of landfilled. While some countries have largely achieved this target, others still have a long way to go. For better understanding the differences arising from local disparities, six factors related to technical, economic, legislative and environmental aspects have been identified as crucial influences in the market share of C&D waste recycling solutions. These factors are able to identify the causes that limit the recycling rate of a certain region. Moreover, progress towards an efficient waste management can vary through the improvement of a single factor. This study provides the background for further fine-tuning the factors and their combination into a mathematical model for assessing the market share of C&D recycling solutions.