Experimental analysis of lateral impact on planar brittle material: spatial properties of the cracks

The breakup of glass and alumina plates due to planar impacts on one of their lateral sides is studied. Particular attention is given to investigating the spatial location of the cracks within the plates. Analysis based on a phenomenological model suggests that bifurcations along the cracks' paths are more likely to take place closer to the impact region than far away from it, i. e., the bifurcation probability seems to lower as the perpendicular distance from the impacted lateral in- creases. It is also found that many observables are not sensitive to the plate material used in this work, as long as the fragment multiplicities corresponding to the fragmentation of the plates are similar. This gives support to the universal properties of the fragmentation process reported in for- mer experiments. However, even under the just mentioned circumstances, some spatial observables are capable of distinguishing the material of which the plates are made and, therefore, it suggests that this universality should be carefully investigated

Acyclic orientations with path constraints

Many well-known combinatorial optimization problems can be stated over the set of acyclic orientations of an undirected graph. For example, acyclic orientations with certain diameter constraints are closely related to the optimal solutions of the vertex coloring and frequency assignment problems. In this paper we introduce a linear programming formulation of acyclic orientations with path constraints, and discuss its use in the solution of the vertex coloring problem and some versions of the frequency assignment problem. A study of the polytope associated with the formulation is presented, including proofs of which constraints of the formulation are facet-defining and the introduction of new classes of valid inequalities

Experimental analysis of lateral impact on planar brittle material

The fragmentation of alumina and glass plates due to lateral impact is studied. A few hundred plates have been fragmented at different impact velocities and the produced fragments are analyzed. The method employed in this work allows one to investigate some geometrical properties of the fragments, besides the traditional size distribution usually studied in former experiments. We found that, although both materials exhibit qualitative similar fragment size distribution function, their geometrical properties appear to be quite different. A schematic model for two-dimensional fragmentation is also presented and its predictions are compared to our experimental results. The comparison suggests that the analysis of the fragments' geometrical properties constitutes a more stringent test of the theoretical models' assumptions than the size distribution

Desempenho produtivo e características de carcaça de cabritos alimentados com diferentes proporções de concentrado.

O objetivo do presente estudo foi avaliar o desempenho produtivo e as características da carcaça de cabritos alimentados com quatro relações de concentrado e volumoso nas rações, tendo como volumoso o capim Elefante in natura picado. As proporções avaliadas foram: 80:20%; 60:40%; 40:60% e 20:80% de con-centrado e volumoso na matéria seca das rações. Foram utilizados 28 caprinos, machos, não castrados, da raça Saanen com peso corporal inicial médio de 9,3 kg distribuídos em quatro lotes de sete animais mantidos em baias coletivas. O delineamento experimental adotado foi o inteiramente casualizado com sete repetições. O aumento nas proporções de concentrado das rações proporcionou maiores pesos corporais finais, os ganhos de peso totais. Além disso, também foram obtidos maiores pesos e rendimentos de carcaça com as maiores doses de concentrado. Assim, tecnicamente é viável o uso de rações com elevado teor de concentrado para caprinos visando a terminação dos mesmos, porém a dose a ser utilizada deverá ser condicionada também em função do desempenho bioeconômico promovido pela suplementação

Fitodisponibilidade de nitrogênio em solo adubado com fertilizante mineral ou lodo de esgoto.

Com a publicação da Política Nacional de Resíduos Sólidos, o lodo de esgoto não poderá ser mais disposto em aterros sanitários. Assim, o uso agrícola se torna ainda mais atrativo. Embora a aplicação deste resíduo ao solo seja normatizada, alguns pontos ainda são questionados, destacando-se a dose calculada a partir da mineralização de nitrogênio quando é realizada mais de uma aplicação ao solo. Portanto, este estudo foi realizado com o objetivo de avaliar a disponibilidade de nitrogênio para plantas de milho em solos previamente tratados com lodo de esgoto. As avaliações foram realizadas em experimento de longo prazo, iniciado em 2001, no qual vem sendo realizada adubação com NPK, dose recomendada de lodo de esgoto ou o dobro desta dose. Concluiu-se que: (i) o teor e a quantidade absorvida de nitrogênio por plantas de milho em solo tratado sucessivamente com a dose recomendada de lodo de esgoto são maiores do que quando é realizada a adubação com NPK; (ii) a quantidade de N absorvida por plantas de milho cultivadas em solo com o dobro da dose recomendada não difere da quantidade absorvida com a adição da dose recomendada, indicando excesso de nitrogênio no solo e maior potencial de contaminação e (iii) a adição do dobro da dose recomendada de lodo de esgoto não resulta em maior produção de massa seca e produtividade quando comparada com a dose recomendada

Electronic State Spectroscopy of Nitromethane and Nitroethane

Funding Information: L.V.S.D., A.S.B., and M.H.F.B. acknowledge support from the Brazilian agencies Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). L.V.S.D., A.S.B., and M.H.F.B. also acknowledge Prof. Carlos de Carvalho for computational support at LFTC-DFis-UFPR and at LCPAD-UFPR. The authors acknowledge the beam time at the ISA synchrotron, Aarhus University, Denmark. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) CALIPSO under grant agreement n° 312284. P.L.V. acknowledges the Portuguese National Funding Agency (FCT) through research grant CEFITEC (UIDB/00068/2020), as well as his visiting professor position at Federal University of Paraná, Curitiba, Brazil. This contribution is also based upon work from the COST Action CA18212-Molecular Dynamics in the GAS phase (MD-GAS), supported by COST (European Cooperation in Science and Technology). Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.High-resolution photoabsorption cross-sections in the 3.7-10.8 eV energy range are reinvestigated for nitromethane (CH3NO2), while for nitroethane (C2H5NO2), they are reported for the first time. New absorption features are observed for both molecules which have been assigned to vibronic excitations of valence, Rydberg, and mixed valence-Rydberg characters. In comparison with nitromethane, nitroethane shows mainly broad absorption bands with diffuse structures, which can be interpreted as a result of the side-chain effect contributing to an increased number of internal degrees of freedom. New theoretical quantum chemical calculations performed at the time-dependent density functional theory (TD-DFT) level were used to qualitatively help interpret the recorded photoabsorption spectra. From the photoabsorption cross-sections, photolysis lifetimes in the terrestrial atmosphere have been obtained for both compounds. Relevant internal conversion from Rydberg to valence character is noted for both molecules, while the nuclear dynamics of CH3NO2 and C2H5NO2 along the C-N reaction coordinate have been evaluated through potential energy curves at the TD-DFT level of theory, showing that the pre-dissociative character is more prevalent in nitromethane than in nitroethane.publishersversioninpres

NUMERICAL ANALYSES OF OPENFOAM'S OVERTOPPING DEVICE SOLUTION

Studies related to ocean energy are getting more important lately, once world claims for renewable energy usage. The Overtopping Device is a kind of Ocean Waves Energy Converter (OWEC), which main concept is storing water provided by incident waves above sea level to feed a set of low head turbines. In order to obtain the desired effect, this device contains a ramp which elevates the incident waves toward the reservoir. Present study aims to perform a numerical model of a 2D Overtopping Device by means of OpenFOAM simulations. OpenFOAM is a free open source code which has shown applicability in many areas of engineering. The adopted solver (InterFOAM) is Volume of Fluid based (VOF) according to Finite Volume Method (FVM), these methodologies has been largely used among researchers in propagating waves field. FLUENT (commercial code) is used to verify OpenFOAM's results. Once, the main point of this paper is to present OpenFOAM as a considerable tool for propagating waves studies, it firstly presents a numerical wave verification with analytical solutions (second order Stokes theory). The second section of results presents overtopping time series peaks in 100 s of simulation. Also, by mass flow rate integration, it presents total mas of water climbed to the reservoir. The integration of mass flow rate takes 94 s of simulation (not 100 s) because it is noticeable a pause between two peaks of overtopping at that time. Results show agreement between wave elevation and wave velocity profiles with straight convergence of periods between analytical and numerical waves. Most important differences are found near air/water interface, owed to faster air flow at that region. Generally OpenFOAM and FLUENT results are similar, with converged overtopping time series peaks and their magnitudes too. Similarly, the amount of water marked by both software are close with very similar trend lines

Meiotic chromosomes and nucleolar behavior in testicular cellas of the grassland spittlebugs Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana (Hemiptera, Auschenorrhyncha).

Spittlebugs annually infest pastures and cause severe damage, representing a serious problem for the tropical American beef cattle industry. Spittlebugs are an important biotic constraint to forage production and there is a lack of cytogenetic data for this group of insects. For these reasons, we conducted this work, in which the spermatogenesis and nucleolar behavior of Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana were studied. The males possessed testes in the shape of a “bunch of grapes”; a variable number of testicular lobes per individual and polyploid nuclei composed of several heteropycnotic bodies. A heteropycnotic area was located in the periphery of the nucleus (prophase I); the chiasmata were terminal or interstitial; metaphases I were circular or linear and anaphase showed late migration of the sex chromosome. The chromosome complement had 2n = 19, except for N. entreriana (2n = 15); the spermatids were round with heteropycnotic material in the center and elongated with conspicuos chromatin. The analysis of testes after silver nitrate staining showed polyploid nuclei with three large and three smaller nucleolar bodies. Early prophase cells had an intensely stained nucleolar body located close to the chromatin and another less evident body located away from the chromatin. The nucleolar bodies disintegrated during diplotene. Silver staining occurred in two autosomes, in terminal and subterminal locations, the latter probably corresponding to the nucleolus organizer regions (NORs). The spermatids were round with a round nucleolar body and silver staining was observed in the medial and posterior region of the elongated part of the spermatid head

Disponibilidade de nitrogênio para plantas de milho cultivadas em solo tratado com doses de lodo de esgoto.

O uso de lodo de esgoto como fertilizante orgânico é uma interessante opção de disposição deste resíduo sólido urbano. Uma das recomendações de cálculo de dose baseia-se na disponibilidade de nitrogênio presente no lodo de esgoto. Ainda existem dúvidas quanto a esta recomendação no que se referem a solos que foram tratados sucessivamente com este resíduo. Este trabalho teve como objetivo estudar a fitodisponibilidade de nitrogênio em solo tratado com lodo de esgoto desde 1999, por meio da avaliação do teor e quantidade absorvida de nitrogênio e produção de massa seca e produtividade de milho. Os tratamentos consistiram na adição de doses crescentes de lodo de esgoto: sem o resíduo, dose recomendada, duas e oito vezes a dose recomendada. A quantidade de nitrogênio (N) absorvida pelas plantas de milho superou a quantidade disponível estimada por meio de cálculo seguindo-se a Resolução 375. No entanto, incrementos na absorção de N e na produtividade da cultura foram observados até dose correspondente a cinco vezes a recomendada, o que significa que a mineralização do Nremanescente de aplicações anteriores não foi suficiente para garantir a produtividade máxima nas condições do estudo. Abstract: The use of sewage sludge as an organic fertilizer is an interesting option for disposal of this urban solid waste. One of the doses calculations is based on sewage sludge nitrogen availability. There are doubts about the suitability of this recommendation for soils treated consecutively with this residue. The objective of this study was to investigate nitrogen phytoavailability in soils treated consecutively with sewage sludge (since 1999) through the evaluation of nitrogen concentration and absorption by corn plants and dry matter and grain production. The treatments consisted on application of increasing doses of sewage sludge. Nitrogen quantity absorbed by maize plants overcame the available quantity estimated following Conama’s Resolution. However, increases on nitrogen absorption and maize productivity were observed until the addition of 5 times the recommended dose. Therefore, the mineralization of nitrogen reminiscent from previous applications was not sufficient to guarantee maximum productivity on the study conditions

Monitoramento do vetor da Huanglongbing (HLB) nos hortos e viveiros produtores de citros e murta na Bahia.

O psilídeo Diaphorina citri, inseto sugador de seiva do floema, é vetor transmissor da bactéria Candidatus Liberibacter que causa a ameaçadora doença dos citros: o Huanglongbing (HLB, ex-greening). A Bahia, o segundo produtor de laranja do país, apresenta o status de área livre desta doença. Além do citros, o D. citri também utilizam como hospedeiro a Murraya paniculata, uma planta ornamental também conhecida como murta.PDF. 154_11