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Unpaved rural roads as source areas of sediment in a watershed of the Brazilian semi-arid region

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International Journal of Sediment Research 2019年第5期34卷 475-485页

作者： Teresa Raquel Lima Farias Pedro Henrique Augusto Medeiros Joaquín Navarro-Hevia José Carlos de Araújo federal institute of Education Science and Technology of Ceará University of Valladolid Campus La Yutera federal University of Ceará Department of Agricultural Engineering Campus do Pici

Approximately 80% of the road network in Brazil is unpaved and shows evidences of a high erosion potential. In the semi-arid Caatinga Biome in the northeast of the country, a monitoring programme has been done for two years in order to analyze runoff and sediment production from unpaved rural roadways and from embankments. Sediment production ranged from 0.30 to 0.92 Mg/ha yr, higher than in undisturbed areas, but generally lower than that reported for unpaved roads in other regions. However,this is a semi-arid area with low rainfall and runoff and, hence, with a limited hydrological connectivity and sediment production. Sediment production on an embankment with no vegetation was around ten times higher than on an embankment with vegetation. On the road surface, annual sediment production(normalized for gradient) in a section with traffic was three times higher than for a road surface without traffic. In addition, events that occurred after roadway maintenance activities generated peaks of sediment concentration of over 5000 mg/L. These results suggest that sediment production from roads and embankments with bare surfaces is at least one order of magnitude higher than in undisturbed catchment areas. Maintenance activity and vehicle traffic contribute to an increase in sediment availability and impact on the sediment concentration, but less intensely on sediment loads, which depend on the runoff magnitude of the events occurring after roadway maintenance. It was also found that the natural vegetation of the semi-arid region potentially captures sediment on roadway embankments; thereby playing an important role in breaking connectivity between the sediment flow from unpaved roads and the natural drainage system of the catchment.

关键词： Sediment production Caatinga vegetation Road maintenance Embankment

Cataracting-centrifuging transition investigation using nonspherical and spherical particles in a rotary drum through CFD simulations

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Particuology 2022年第1期20卷 48-60页

作者： Wanessa M.Benedito Claudio R.Duarte Marcos A.S.Barrozo Dyrney A.Santos institute of Chemistry Federal University of Goias-UFGCampus SamambaiaGoianiaGO74690-900Brazil School of Chemical Engineering Federal University of Uberlandia-UFUCampus Santa MonicaUberlandiaMG38408-144Brazil

This paper aims to systematically investigate the cataracting-centrifuging transition in a rotary drum involving spherical and nonspherical particles by using the Multiphase Granular Eulerian Model(MGEM).The effects of drum length and particle shape on the cataracting-centrifuging transition behavior were *** results showed that drum length plays an important role in the cataracting-centrifuging transition,although most related works in the literature do not consider *** particle shape also significantly affects the cataracting-centrifuging transition *** particles required lower rotation speeds than spherical particles to reach the centrifuging *** particle shape was shown to be related to the critical solid fraction(asc)from Schaeffer’s model,although further investigations are required to completely correlate particle spherecity with critical solid volume fractions.

关键词： Frictional viscosity MGEM model Particle shape Drum length Drum flow regimes

Iron toxicity resistance strategies in tropical grasses:The role of apoplastic radicular barriers

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Journal of Environmental Sciences 2019年第4期31卷 257-266页

作者： Advanio Inacio Siqueira-Silva Camilla Oliveira Rios Eduardo Gusmao Pereira institute of Biological and Health Sciences Federal University of Vicosa (UFV)Campus Florestal Minas Gerais Brazil federal University of Western Para (UFOPA) University Campus of JurutiPara Brazil Postgradute Program in Management and Conservation of Natural and Agrarian Ecosystems UFV Campus Florestal Florestal Minas Gerais Brazil

The revegetation of mined areas poses a great challenge to the iron ore mining *** initial recovery process in degraded areas might rely on the use of Fe-resistant *** grasses, such as Paspalum densum and Echinochloa crus-galli, show different resistance strategies to iron toxicity; however, these mechanisms are poorly *** Fe-resistance mechanisms and direct iron toxicity as a function of root apex removal were investigated. To achieve this purpose, both grass species were grown for up to 480 hr in a nutrient solution containing 0.019 or 7 mmol/L Fe-EDTA after the root apices had been removed or maintained. Cultivation in the presence of excess iron-induced leaf bronzing and the formation of iron plaque on the root surfaces of both grass species, but was more significant on those plants whose root apex had been removed. Iron accumulation was higher in the roots, but reached phytotoxic levels in the aerial parts as well. It did not hinder the biosynthesis of chloroplastidic pigments. No significant changes in gas exchange and chlorophyll a fluorescence occurred in either grass when their roots were kept intact; the contrary was true for plants with excised root apices. In both studied grasses, the root apoplastic barriers had an important function in the restriction of iron translocation from the root to the aerial plant parts, especially in E. crus-galli. Root apex removal negatively influenced the iron toxicity resistance mechanisms(tolerance in P. densum and avoidance in E. crus-galli).

关键词： Paspalum densum Echinochloa crus-galli Apoplastic barrier Iron toxicity

Carbon Dots-Doped Electrospun Fibers for Simultaneous Metal Ion Detection and Adsorption of Dyes

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Advanced Fiber Materials 2020年第6期2卷 302-313页

作者： Mário César A.de Oliveira Elisângela G.de L.Oliveira Indira C.B.Pires Iuri C.M.Candido Nikifor Rakov Helinando P.de Oliveira Yutao Xing Glauco S.Maciel institute of Materials Science Universidade Federal do Vale do São FranciscoJuazeiroBA 48920-310Brazil Instituto de Física Universidade Federal FluminenseNiteróiRJ 24210-346Brazil

The required treatment and monitoring of contaminants in wastewater reinforces the development of low-cost adsorbents/chemosensors,introducing advantages relative to the detection/removal of toxic metals and ***,it is reported a two-step process of fabrication of fluorescent carbon dots via the hydrothermal treatment of amino acids for the following encapsulation in electrospun *** prominent anionic behavior of electrospun fibers of Eudragit L100 was explored for adsorption of cationic dyes(methylene blue and crystal violet)-with the prevailing electrostatic interaction of parts being favored by the formation of monolayers on the surface of *** the other hand,the controlled release of carbon dots(CDs)from fibers to the reactor can be explored for a second application:the nitrogen ligands from released glycine-based carbon dots can be explored to indicate the presence of metal ions in aqueous *** experiment resulted in a quenching in the fluorescence of the CDs in order of 90%in the emission of particles in the response of the presence of Fe^(3+) ions,characterizing a promising perspective for this experimental system.

关键词： Fluorescence Ferric ion detection Electrospinning Carbon nanostructure

Use of ultrasound to modify the pyrolyzed biomass of Pinus *** the implications for biological models

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Information Processing in Agriculture 2018年第2期5卷 199-204页

作者： Aislan R.Guimaraes Marcelo E.Cordeiro Jaqueline Nicolini Keller P.Nicolini Chemistry Department Federal Institute of ParanaCampus PalmasPR CEP 85555-000Brazil

Pine(Pinus ssp.)needle biomass(PNB)was pyrolyzed at 400℃ for 3 h and then subjected to hydrothermal treatment at the same temperature for 10 min,with and without the addition of potassium chloride(KCl).The suspensions of the materials treated hydrothermally were submitted to ultrasound for 5,10,20,30 and 60 *** reflectance UV-Vis(DRUV)spectroscopy results for the materials with variations in sonication times were obtained and the band gap energy(E)was calculated.A culture medium containing Saccharomyces cerevisiae was monitored during 30 min of exposure to different materials for the calculation of the 10%(IC10),30%(IC30)and 50%(IC50)inhibitory *** the samples that underwent ultrasonic treatment,the material pyrolyzed at 400℃ without the addition of potassium ions(PNB4003H60)presented the greatest inhibition of 10% of the Saccharomyces cerevisiae *** the materials without the addition of potassium,the material pyrolyzed and sonicated for 10 min(PNB4003H10)showed the best characteristics for use as a support for Saccharomyces cerevisiae organisms.

关键词： Potassium Saccharomyces cerevisiae Spectroscopy

Fractionation of rare earth and other trace elements in crabs,Ucides cordatus,from a subtropical mangrove affected by fertilizer industry

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Journal of Environmental Sciences 2017年第4期29卷 69-76页

作者： Alice Bosco-Santos Wanilson Luiz-Silva Emmanoel Vieira da Silva-Filho Monique Dias Corrêa de Souza Elton Luiz Dantas Margareth Sugano Navarro State University of Campinas (UNICAMP) Institute of Geosciences Department of Geology and Natural Resources Campinas Sao Paulo 13083870 Brazil . fluminense federal University (UFF) Institute of Chemistry Department of Geochemistry Niteroi Rio de Janeiro 24900970 Brazil University of Brasília(UnB) Institute of Geosciences Department of Geology Brasflia Distrito Federal 70910900 Brazil

Fractionation of rare earth elements（REE） and other trace metal concentrations（Th, U, Cd,Cr, Cu, Ni, Pb, and Zn） between mangrove sediments and claw muscles and shells of male crabs（Ucides cordatus） from a subtropical estuary highly impacted by fertilizer industry activities was investigated. This is the first record of REE distribution in these organisms,and the results showed higher accumulations of these metals, U and Th in shells, probably related to the replacement of Ca during molting. Contents of Cd, Cr and Ni were similar in both tissues, but Cu, Zn and Pb were mostly accumulated in the claw muscle with concentrations above those considered safe for human consumption according to the Brazilian legislation. REE fractionation was different in the analyzed tissues being softer in the shells. The results provided evidences that the water absorbed during molting controls the chemistry of REE in shells. In contrast, the chemistry of REE in the claw muscle, in which was observed preferential absorption of light REE, is controlled by diet. REE fractionation obtained for the claw muscles was closely correlated to the observed in the contaminated substrate and in materials related to the production of phosphate fertilizers（contamination source）, which supports their transference to this Ucides cordatus tissue without fractionation by the ingestion of sediments. Our results showed the potential use of crab tissues for monitoring REE and trace element sources in mangrove areas, with claw muscle exhibiting the contaminant source fingerprint.

关键词： Rare earth elements Trace metals Fertilizer contamination Crabs

Discovery of the marine Eocene in the northern South China Sea

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National Science Review 2019年第5期6卷 881-886页

作者： Zhimin Jian Haiyan Jin Michael A Kaminski Fabricio Ferreira Baohua Li Pai-Sen Yu State Key Laboratory of Marine Geology Tongji University Geosciences Department King Fahd University of Petroleum and Minerals institute for Geosciences Universidade Federal Fluminense Nanjing institute of Geology and Paleontology Chinese Academy of Sciences Applied Research Laboratories(NARLabs) Taiwan Ocean Research Institute(TORI)

The nature of the Eocene stratigraphy of the South China Sea (SCS) has been a mystery for *** the southern SCS, the Eocene system with marine deposits is often considered as representing part of the ‘Proto-South Chin... 详细信息

关键词： SCS Sr Discovery of the marine Eocene in the northern South China Sea China

Graphene's photonic and optoelectronic properties——A review

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Chinese Physics B 2020年第3期29卷 13-35页

作者： A J Wirth-Lima P P Alves-Sousa W Bezerra-Fraga Department of Physics Federal Institute of EducationScience and Technology of Ceara Campus SobralCearaBrazil Postgraduate Program in Electrical Engineering and Computing federal University of Ceara(U.F.C.)Sobral CearaBrazil

Due to its remarkable electrical and optical properties,graphene continues to receive more and more attention from researchers around the *** excellent advantage of graphene is the possibility of controlling its charge density,and consequently,the management of its conductivity and dielectric constant,among other *** is noteworthy that the control of these properties enables the obtaining of new optical/electronic devices,which would not exist based on conventional ***,to work in this area of science,it is necessary to have a thorough knowledge regarding the electrical/optical properties of *** this review paper,we show these graphene properties very well detailed.

关键词： absorbance conductivity dielecric constant dispersion relation

Cerium alleviates drought-induced stress in Phaseolus vulgaris

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Journal of Rare Earths 2020年第3期38卷 324-331页

作者： Olívia Graziela Gelioli Salgado Jéssica Cristina Teodoro Joyce Pereira Alvarenga Cynthia de Oliveira Teotonio Soares de Carvalho Débora Domiciano Paulo Eduardo Ribeiro Marchiori Luiz Roberto Guimaraes Guilherme Department of Soil Science Federal University of LavrasCP 3037Campus UFLALavras37200-000Brazil Department of Biology Federal University of LavrasCP 3037Campus UFLALavras37200-000Brazil

Extreme drought events are expected to be one of the main challenges for tropical agriculture and,consequently,for global food *** this reason,it is urgent to develop strategies to increase water use efficiency,as well as to increase crops’ ability to cope with *** rare earth elements(REEs) are known to alleviate damages in plants under abiotic stresses,we hypothesized that addition of Ce^3+to nutrient solution would promote the growth of common bean,especially under simulated drought *** test this hypothesis,we conducted an experiment evaluating the effect of six Ce^3+concentrations on the development and physiological traits of common bean grown in nutrient solution under normal condition and under induced drought stress,caused by the addition of polyethylene glycol6000 to the nutrient *** results show that Ce^3+alleviates water stress in common bean plants,increasing their survival rate and *** addition,Ce^3+application increases photosynthesis rate,chlorophyll content and water use efficiency under water ***,we observe no significant effect of Ce^3+on plants growing under normal ***,Ce3+seems to be a promising attenuator of drought stress for common bean.

关键词： Water stress Polyethylene glycol Rare earth elements Cerium nitrate Mitigation Common bean