793 research outputs found
Controle Alternativo De Pinta-preta Em Genótipos De Mamoeiro
To find control forms alternative to fungicides, this study aimed to evaluate the effect of products with potential to control black spot (Asperisporium caricae) in different papaya genotypes. Installed in a greenhouse, the experiment was conducted in randomized blocks (RB) with factorial arrangement 5x6, three replicates, and spraying of four products (Bion®, Bordeaux mixture, Ecolife®, and Bordasul®) in six papaya genotypes (‘Sunrise Solo PT’, ‘STZ 03’, ‘Golden’, ‘Tailândia’, ‘Maradol’ and ‘UENF-CALIMAN 01’), while control was sprayed only with water. The severity (BSS) and the incidence (BSI) of black spot on the leaves were quantified, as well as the area under the disease progress curve (AUDPC). There was variability among the evaluated genotypes, highlighting ‘STZ 03’, ‘Maradol’ and ‘UENF/ CALIMAN 01’ as the most resistant genotypes. ‘Tailândia’ (susceptible) showed greater response to the products. Plants sprayed with Bion®, Bordeaux mixture and Bordasul® had reduced black spot means. © 2017, Universidade Estadual Paulista (UNESP). All rights reserved.431606
Nanoindentation study of the interfacial zone between cellulose fiber and cement matrix in extruded composites
[EN] The present study shows the application of the nanoindentation technique to evaluate the properties of
the cellulose fiber-cement matrix interfacial zone in composites prepared with an auger extruder. The
degree of strength of the bond between fiber and matrix is recognized as important variable that influences
macro-mechanical properties, such as modulus of rupture and toughness of cement based
composites. The nanoindentation measurements showed the highest hardness and elastic modulus in
the part inner of the cellulosic fiber after hydration process due to precipitation and re-precipitation of
cement hydration products. These results indicate that mineralization of the cellulosic fibers can affect
the stress distribution and interfacial bond strength in the cement based composite.The authors acknowledge by financial support provided by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP, process no 2013/03823-8), Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, process no 3886/2014) and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq, process no 152069/2016), in Brazil. Special thanks for Fibria and Infibra for providing raw materials the development of this work.Teixeira, R.; Tonoli, G.; Santos, S.; Rayón, E.; Amigó, V.; Savastano, HJ.; Rocco Lahr, F. (2018). Nanoindentation study of the interfacial zone between cellulose fiber
and cement matrix in extruded composites. Cement and Concrete Composites. 85:1-8. https://doi.org/10.1016/j.cemconcomp.2017.09.018S188
Impact of content and length of curauá fibers on mechanical behavior of extruded cementitious composites: Analysis of variance
[EN] The use of composite materials in construction has grown considerably in recent years, such as cementitious matrices and concrete reinforced with fibers. The vegetable fibers have become an alternative due to its abundance, low cost and low energy consumption for its production, and appropriate properties mechanical. Curauá fiber is a plant native from Amazonas harvested manually in commercial farming and it is used in the manufacture of ropes and baskets or as reinforcement in composite with organic matrix of components for cars, buses and trucks. On the other hand, the extrusion process can produce composites with high-density matrix with fibers, low permeability and good interface between fiber and matrix. This process is also compatible with the use of vegetable fibers as raw materials in the production of cost-effective construction elements such as ceiling panels and drywalls. The objective of this research was use the analysis of variance (ANOVA) for evaluating with rigor mathematical the influence of content and length of curauá fibers on the mechanical behavior
of the extruded cementitious composites. Composites without fibers and reinforced with 1% and 2% by mass of fibers as well as 6 mm and 10 mm of length these curauá fibers were evaluated. The composites with fibers of 10 mm have showed better mechanical results. Besides, the composites with fibers curauá after 200 accelerated aging cycles were better than one non-aging.The authors acknowledge the financial support provided by Brazilian Agencies: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Grant nº 2013/03823-8 and 2012/51467-3); Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES, Grant nº 3886/2014); and Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq, Grant nº 406429/2015 and 312151/2016-0). The authors thank the Brazilian companies Fibria S.A., Infibra S.A. and Imbralit Ltda. for technical support to the development of this work.Teixeria, R.; Santos, S.; Christoforo, A.; Paya Bernabeu, JJ.; Savastano Jr., H.; Rocco Lhar, F. (2019). Impact of content and length of curauá fibers on mechanical behavior of extruded cementitious composites: Analysis of variance. Cement and Concrete Composites. 102:134-144. https://doi.org/10.1016/j.cemconcomp.2019.04.022S13414410
Nonequilibrium wetting transitions with short range forces
We analyze within mean-field theory as well as numerically a KPZ equation
that describes nonequilibrium wetting. Both complete and critical wettitng
transitions were found and characterized in detail. For one-dimensional
substrates the critical wetting temperature is depressed by fluctuations. In
addition, we have investigated a region in the space of parameters (temperature
and chemical potential) where the wet and nonwet phases coexist. Finite-size
scaling analysis of the interfacial detaching times indicates that the finite
coexistence region survives in the thermodynamic limit. Within this region we
have observed (stable or very long-lived) structures related to spatio-temporal
intermittency in other systems. In the interfacial representation these
structures exhibit perfect triangular (pyramidal) patterns in one (two
dimensions), that are characterized by their slope and size distribution.Comment: 11 pages, 5 figures. To appear in Physical Review
Low temperature behavior of poultry fat biodiesel:diesel blends
AbstractAs the worldwide consumption of poultry meat rises the use of poultry fat as a feedstock for biodiesel production becomes attractive considering economical and environmental reasons. However, poultry fat biodiesel still faces some restrictions due to its poor flow properties at low temperatures. In this study ethylic and methylic poultry fat biodiesels and their blends with diesel were evaluated in terms of flow properties. Modulated Temperature Differential Scanning Calorimetry (MT-DSC) was used to understand the physical meaning of properties as Cold Filter Plugging Point (CFPP), Pour Point (PP) and Cloud Point (CP), widely used in biodiesel characterization. Based on the MT-DSC studies, it was observed that the first crystallization peak temperature had values similar to CFPP and CP. This way CP was found to be associated with the first solidified material and not with the early formation of the first nuclei, as normally reported. On the other hand, these crystals already lead to the flow decrease, as indicate by the CFPP results. PP values were close to the second crystallization peak temperature, not being related to the complete solidification of the fuel
Mining for peaks in lc-hrms datasets using finnee - a case study with exhaled breath condensates from healthy, asthmatic, and copd patients
This work was financially supported by the projects: (i) UID/ EQU/00511/2019 - Laboratory for Process Engineering, Environment, Biotechnology and Energy − LEPABE funded by national funds through FCT/MCTES (PIDDAC); (ii) POCI-01-0145-FEDER-029702 and POCI-01-0145-FEDER031297 funded by FEDER funds through COMPETE2020 − Programa Operacional Competitividade e Internacionalizaca̧ õ (POCI) and by national funds (PIDDAC) through FCT/ MCTES; (iii) AstraZeneca − Projecto OLDER (CEDOC/ 2015/59); (iv) iNOVA4Health - UID/Multi/04462/2013, financially supported by FCT/Ministerio da Educação e Ciência, and co-funded by FEDER under the PT2020 Partnership Agreement.Separation techniques hyphenated to high-resolution mass spectrometry are essential in untargeted metabolomic analyses. Due to the complexity and size of the resulting data, analysts rely on computer-assisted tools to mine for features that may represent a chromatographic signal. However, this step remains problematic, and a high number of false positives are often obtained. This work reports a novel approach where each step is carefully controlled to decrease the likelihood of errors. Datasets are first corrected for baseline drift and background noise before the MS scans are converted from profile to centroid. A new alignment strategy that includes purity control is introduced, and features are quantified using the original data with scans recorded as profile, not the extracted features. All the algorithms used in this work are part of the Finnee Matlab toolbox that is freely available. The approach was validated using metabolites in exhaled breath condensates to differentiate individuals diagnosed with asthma from patients with chronic obstructive pulmonary disease. With this new pipeline, twice as many markers were found with Finnee in comparison to XCMS-online, and nearly 50% more than with MS-Dial, two of the most popular freeware for untargeted metabolomics analysis.publishersversionpublishe
Thermodynamics of charged and rotating black strings
We study thermodynamics of cylindrically symmetric black holes. Uncharged as
well as charged and rotating objects have been discussed. We derive surface
gravity and hence the Hawking temperature and entropy for all these cases. We
correct some results in the literature and present new ones. It is seen that
thermodynamically these black configurations behave differently from
spherically symmetric objects
Domain wall roughening in dipolar films in the presence of disorder
We derive a low-energy Hamiltonian for the elastic energy of a N\'eel domain
wall in a thin film with in-plane magnetization, where we consider the
contribution of the long-range dipolar interaction beyond the quadratic
approximation. We show that such a Hamiltonian is analogous to the Hamiltonian
of a one-dimensional polaron in an external random potential. We use a replica
variational method to compute the roughening exponent of the domain wall for
the case of two-dimensional dipolar interactions.Comment: REVTEX, 35 pages, 2 figures. The text suffered minor changes and
references 1,2 and 12 were added to conform with the referee's repor
Bulk dynamics for interfacial growth models
We study the influence of the bulk dynamics of a growing cluster of particles
on the properties of its interface. First, we define a {\it general bulk growth
model} by means of a continuum Master equation for the evolution of the bulk
density field. This general model just considers arbitrary addition of
particles (though it can be easily generalized to consider substraction) with
no other physical restriction. The corresponding Langevin equation for this
bulk density field is derived where the influence of the bulk dynamics is
explicitly shown. Finally, when it is assumed a well-defined interface for the
growing cluster, the Langevin equation for the height field of this interface
for some particular bulk dynamics is written. In particular, we obtain the
celebrated Kardar-Parisi-Zhang (KPZ) equation. A Monte Carlo simulation
illustrates the theoretical results.Comment: 6 pages, 2 figure
Nonequilibrium wetting
When a nonequilibrium growing interface in the presence of a wall is
considered a nonequilibrium wetting transition may take place. This transition
can be studied trough Langevin equations or discrete growth models. In the
first case, the Kardar-Parisi-Zhang equation, which defines a very robust
universality class for nonequilibrium moving interfaces, with a soft-wall
potential is considered. While in the second, microscopic models, in the
corresponding universality class, with evaporation and deposition of particles
in the presence of hard-wall are studied. Equilibrium wetting is related to a
particular case of the problem, it corresponds to the Edwards-Wilkinson
equation with a potential in the continuum approach or to the fulfillment of
detailed balance in the microscopic models. In this review we present the
analytical and numerical methods used to investigate the problem and the very
rich behavior that is observed with them.Comment: Review, 36 pages, 16 figure
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