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environmental parameters and tree physiology in two semiarid land use systems in Brazil

Journal of Forestry Research 2019年第2期30卷 397-407页

作者： Marlete Moreira Mendes Ivanov Claudivan Feitosa de Lacerda Francisco eden Fernandes Paiva Ana Clara Rodrigues Cavalcante Teogenes Senna de Oliveira departamento de Biologia Universidade Federal do Piaui departamento de engenharia Agricola Campus do PiciUniversidade Federal do Ceara embrapa Caprinos e Ovinos departamento de Solos Universidade Federal de Vicosa

To determine if reduced tree densities(number of trees per unit area) lead to changes in micro-meteorological and tree physiological characteristics, two areas with different tree densities were assessed. One was an agrosilvopastoral system(AGP) with low tree density, and the other, a secondary forest(SF) with greater tree numbers, both located in a semiarid region of Brazil. Data were collected simultaneously by two automated weather stations: rainfall, air(T_a) and soil temperatures(T_(s5 cm)), relative humidity(RHair), photosynthetically active radiation(PAR), soil moisture at two depths(M_(s30 cm)and M_(s50 cm)),and wind velocity(Vw). Net photosynthesis in Cordia oncocalyx Allema?o trees was measured with an infrared gas analyzer in February, March, May, July, August and September 2011, which encompasses a rainy period followed by a dry period. Average values of Ta, T_(s5 cm), Vwand PAR were greater and average values of RHairand M_(s50 cm) were lesser in the AGP. Photosynthetic rates were greater in plants growing under the AGP at the onset of the dry season when Vw, PAR and T_(s5 cm)were greater and M_(s50 cm) was lesser. Photosynthetic rates correlated strongly with physical parameters during the dry season, especially under SF. Differences in tree numbers between AGP and SF led to differences in physical environmental parameters;however, the latter had less influence on photosynthetic rates in C. oncocalyx during the rainy season. During the dry season, all physical parameters had an impact on net photosynthesis under SF but not under AGP. This indicates a certain independence of plants in AGP.

关键词： Agrosilvopastoral system Net photosynthesis Secondary forest Tree density

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TRANSIeNT ANALYSIS OF COMPOSITe PLATeS BY A LOCAL RADIAL BASIS FUNCTIONS-FINITe DIFFeReNCe TeCHIQUe

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Acta Mechanica Solida Sinica 2012年第1期25卷 22-36页

作者： C.M.C.Roque D.Cunha A.J.M.Ferreira INeGI Faculdade de Engenharia da Universidade do PortoRua Dr.Roberto Frias departamento de engenharia Mecnica Faculdade de Engenharia da Universidade do PortoRua Dr.Roberto Frias

The use of local numerical schemes,such as finite differences produces much better conditioned matrices than global collocation radial basis functions ***,finite differ-ence schemes are limited to special *** scattered points,a combination of finite differences and radial basis functions would be a possible *** this paper,we use a higher-order shear deformation plate theory and a radial basis function-finite difference technique for predicting the transient behavior of thin and thick composite *** numerical experiments on beams and composite plates,the accuracy and efficiency of this collocation technique is demonstrated.

关键词： meshless beam composite plate

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effect of operating conditions and potassium content on Fischer-Tropsch liquid products produced by potassium-promoted iron catalysts

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Journal of Natural Gas Chemistry 2008年第2期17卷 175-178页

作者： Francisco e.M.Farias Fernando G.Sales Fabiano A.N.Fernandes Universidade Federal do Ceará Departamento de Engenharia QuímicaCampus do PiciBloco 70960455-760 Fortaleza-CEBrazil

The dependencies of Fischer-Tropsch synthesis liquid hydrocarbon product distribution on operating pressure and temperature have been studied over three potassium-promoted iron catalysts with increasing potassium molar content. The study followed an experimental planning and the results were analyzed based on surface response methodology. The effects of different operating conditions and potassium contents on the liquid product distribution were compared based on number average carbon number and dispersion. Results showed that high pressures （25 to 30 arm） favored the production of waxes that could be converted into liquid fuels through hydrocracking, while greater direct selectivity towards diesel was favored by low pressure （20 arm） using catalysts with low potassium to iron molar ratios. The liquid product distribution produced using an iron catalyst with high potassium content presented higher number-average number of carbons when compared to the distribution obtained using an iron catalyst with low potassium content.

关键词： Fischer-Tropsch synthesis liquid fuels iron-based catalyst potassium

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DC Plasma Technology Applied to Powder Metallurgy: an Overview

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Plasma Science and Technology 2013年第1期15卷 70-81页

作者： A. N. KLeIN R. P. CARdoSO H. C. PAVANATI C. BINdeR A. M. MALISKA G. HAMMeS D. FUSAO A. SeeBeR S. F. BRUNATTO J. L. R. MUZART LabMat (Materials Laboratory) Departamento de Engenharia Mec~nica Universidade Federal de Santa Catarina (UFSC) 88040-900 FlorianSpolis - SC Brazil departamento de engenharia Mecanica Universidade Federal do Parana (UFPR) 81531-990 Curitiba- PR Brazil departamento Academico de Metal-Mecanica Instituto Federal de Santa Catarina (IFSC) 88020-300 Florianopolis - SC Brazil Universidade Tecnologica Federal do Parana (UTFPR) 84016-210 Ponta Grossa - PR Brazil Centro de Ciencia e Tecnologia Universidade de Caxias do Sul 95070-560 Caxias do Sul- RS Brazil

DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic characteristics of DC plasma technology, which make it suitable for powder metallurgy （PM） and powder injection molding （PIM） parts production, are low- pressure processing and plasma environment high reactivity. Moreover it can be considered as a highly competitive green technology. In this work, an overview of some of the important DC plasma techniques applied to PM and PIM parts processing is presented. emphasis is given to the descriptions of the main characteristics and the technique potentials of plasma-assisted nitriding, plasma-assisted thermal debinding, plasma-assisted sintering, and simultaneously plasma-assisted sintering and surface alloying. The aspects presented and discussed in this paper indicate that DC plasma processes are promising and competitive techniques for PM and PIM parts processing.

关键词： powder metallurgy DC glow discharge plasma nitriding plasma sintering,plasma-assisted thermal debinding surface alloying

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Growth of Variable Aspect Ratio ZnO Nanorods by Solochemical Processing

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Journal of Materials Science & Technology 2015年第1期31卷 10-15页

作者： Marivone Gusatti Daniel A.R.Souza Nivaldo C.Kuhnen Humberto G.Riella departamento de engenharia Química e engenharia de Alimentos Programa de Pós-Graduacao em Engenharia Química LABMAC Universidade Federal de Santa Catarina (UFSC) Campus UniversitárioCP 476 Florianópolis Santa Catarina 88040-900 Brazil

In this work,variable aspect ratio（length divided by diameter） zinc oxide nanorods were synthesized through a simple solochemical method by reacting a Zn2+precursor with sodium hydroxide at low reaction *** analysis of the X-ray diffraction data indicated that the samples had hexagonal wurtzite structure and nanometric size *** transmission electron microscopy（TeM） images of the products prepared at60 and 80 ℃ exhibited rod-like architecture,showing that the reaction temperature did not affect the ZnO *** average aspect ratio of the ZnO nanorods decreased from 3.4 to 2.4 when the reaction temperature was raised from 60 to 80 ℃.The samples presented a blue shift in the excitonic absorption compared to ZnO bulk that increased alongside with reaction *** addition,this research investigated the results obtained by varying the concentration of zinc chloride *** the same temperature,it could be verified that when the zinc concentration was increased,the diameter of the ZnO nanorods also slightly increased,and much shorter nanorods were achieved,especially in the reactions performed at 50 and 70 ℃.Finally,the growth mechanism of the ZnO nanostructures was proposed based on the results obtained by changing the zinc precursor concentration and reaction temperature.

关键词： Chemical synthesis ZnO nanorods Growth mechanism

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Bioactive extracts of red seaweeds Pterocladiella capillacea and Osmundaria obtusiloba(Floridophyceae:Rhodophyta) with antioxidant and bacterial agglutination potential

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Asian Pacific Journal of Tropical Medicine 2016年第4期9卷 363-370页

作者： Daniel Barroso de Alencar Fátima Cristiane Teles de Carvalho Rosa Helena Rebouas Daniel Rodrigues dos Santos Kelma Maria dos Santos Pires-Cavalcante Rebeca Larangeira de Lima Bárbara Mendes Baracho Rayssa Mendes Bezerra Francisco Arnaldo Viana Regine Helena Silva dos Fernandes Vieira Alexandre Holanda Sampaio Oscarina Viana de Sousa Silvana Saker-Sampaio Laboratrio de Produtos Naturais Marinhos.departamento de engenharia de Pesca Universidade Federal do Ceará.Campus do Pici.Ar.Mister Hull.s/nCaixa Postal 6043 Laboratrio de Microbiologia Ambiental e do Pescado.Instituto de Ciências do Mar.Universidade Federal do Ceará.Av.da Abolicao 3207 Laboratrio de Microbiologia Ambiental e do Pescado.Instituto de Ciências do Mar.Universidade Federal do Ceará Laboratrio de Produtos Naturais Marinhos.departamento de engenharia de Pesca Universidade Federal do Ceará Laboratrio de Cromatografia Departamento de QuimicaUniversidade do Estado do Rio Grande do NorteCampus Universitário Central

Objective:To evaluate the antioxidant,antibacterial and bacterial cell agglutination activities of the hexane(Hex) and 70%ethanol(70%etOH) extracts of two species of red seaweeds Pterocladiella capillacea(***) and Osmundaria ***:In vitro antioxidant activity was determined by DPPH radical scavenging assay,ferric-reducing antioxidant power assay,ferrous ion chelating assay,β-carotene bleaching assay and total phenolic content *** activity was tested using the method of disc diffusion on Mueller-Hinton *** ability of algal extracts to agglutinate bacterial cells was also ***:The 70%etOH extract of the two algae showed the highest values of total phenolic content compared to the Hex *** results of DPPH for both extracts(Hex,70%etOH) of Osmundaria obtusiloba(43.46%and 99.47%) were higher than those of ***(33.04%and 40.81%) at a concentration of 1 000 μg/*** for the ferrous ion chelating,there was an opposite behavior,extracts of *** had a higher *** extracts showed a low ferric-reducing antioxidant power,with optical density ranging from0.054 to *** activities of all extracts evaluated for β-carotene bleaching were above 40%.There was no antibacterial activity against bacterial strains ***,the extracts of both species were able to agglutinate bacterial Gram positive cells of Staphylococcus aureus and Gram negative cells of escherichia coli,multidrug-resistant Salmonella and Vibrio *** This is the first report of the interaction between these algal extracts,rich in natural compounds with antioxidant potential,and Gram positive and Gram negative bacterial cells.

关键词： Bioactive compounds Antioxidant Bacterial agglutination Rhodophyta

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Influence of Microstructures on Polarization Resistance and Hydrogen-Induced Cracking of a Micro-Alloyed Steel Submitted to Different Cooling Rates

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Journal of Iron and Steel Research International 2011年第S1期18卷 168-172页

作者： González M R Martins de Araújo D S Goldenstein H Alonso-Falleiros N departamento de engenharia Metalúrgica e de Materiais EscolaPolitécnicaUniversidade de Sao Paulo-SP-Brasil

The effect of different microstructures on the polarization resistance (Rp) and the hydrogen-induced cracking (HIC) of a micro-alloyed steel austenitized and submitted to different cooling rates was *** 19.1 x 6 x 2 mm,containing the whole thickness of the plate were extracted from a 20 mm plate and heat treated on a quenching dilatometer,were submitted to Rp and HIC corrosion *** Rp and HIC tests followed as close as possible ASTM G59 and NACe standard TM0284-2003,in this case,modified only with regard to the size of the *** samples transformed from austenite by a slow cooling (cooling rate of 0.5℃.s-1) showed higher susceptibility to hydrogen-induced cracking,with large cracks in the middle of the sample propagating along segregation bands,corresponding to the centerline of the plate *** cooling rates of 10℃.s-1,only small cracks were found in the matrix and micro cracks nucleated at non-metallic *** higher cooling rates (40℃.s-1) very few small cracks were detected,linked to non-metallic *** result suggests that structures formed by polygonal structures and segregation bands (were eutectoid microconstituents predominate) have higher susceptibility to *** predominantly formed by acicular ferrite make it difficult to propagate the cracks among non-oriented and interlaced acicular ferrite *** segregation bands containing eutectoid products also help inhibit cracking and crack propagation;segregation bands can function as pipelines for hydrogen diffusion and offer a path of stress concentration for the propagation of cracks,frequently associated to non-metallic *** resistance essays performed on the steel in theas received condition,prior to any heat treatment,showed larger differences between the regions of the plate,with a considerably lower Rp in the *** austenitization heat treatments followed by cooling rates of 0.5 e 10℃.s-1 made more uniform the

关键词： hydrogen induced cracking polarization resistance micro-alloyed steel control cooling

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Small river basin and estuarine sediment fluxes:The magnitude necessary for coastal dispersion and siltation effects on a coral reef

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International Journal of Sediment Research 2019年第6期34卷 591-599页

作者： Paula Sagili?o Isacksson eduardo Guilherme Gentil de Farias Francisco José Dias Roberto Nascimento de Farias Anandra Machado Francisco de Assis esteves Mauricio Mussi Molisani Instituto de Biodiversidade e Sustentabilidade (NUPeM/UFRJ) Universidade Federal do Rio de Janeiro Grupo de Gestao Ecologia e Tecnologia Marinha (GTMar)Departamento de Engenharia de Pesca a Ciencias Biologicas (DEPB)Universidade do Estado de Santa Catarina (UESC) Laboratorio de Hidrodinamica Costeira Estuarina e de Aguas Interiores (LHiCEAI)Departamento de Oceanografia e Limnologia (DEOLI)Universidade Federal do Maranhao (UFMA) Programa de Pos-Graduacao em Ciencias Ambientais e Conservacao-PPGCIAC Instituto de Biodiversidade e Sustentabilidade (NUPEM/UFRJ)

Increasing continental suspended sediment influx to coral reefs is an example of land-sea coupling that requires the identification of sources,magnitude of transport,and controlling *** Brazil,a small coastal basin(Macae River) was identified as a source of suspended sediment to a coral reef on the coast of Cape Armacao dos *** suspended sediment loads were measured at the basin as were fluxes within the estuary and towards the coast during eight tidal *** load and yield from this basin were typical of small coastal basins,showing high to moderate slopes and transitional land ***,the magnitude of the river loads was lower than the sediment transport within the estuary,indicating that the estuary amplifies river fluxes and sustains the transference of suspended sediment alongshore to the coral ***,the estuary displays both suspended particle retention and export capacity and,therefore,fluxes to the coast and the coral reef occur as episodic events.

关键词： Suspended matter Watershed Mass-balance budget Campos Basin

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Species-specific biomass allometric models and expansion factors for indigenous and planted forests of the Mozambique highlands

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Journal of Forestry Research 2021年第3期32卷 1047-1065页

作者： Tarquinio Mateus Magalhaes Victoria Norberto Cossa Benard Soares Guedes Amélia Saraiva Monguela Fanheiro departamento de engenharia Florestal Faculdade de Agronomia e Engenharia FlorestalUniversidade Eduardo MondlaneCampus UniversitárioEdifício no.1257MaputoRepública de Mocambique departamento de Sociologia Rural Escola Superior de Desenvolvimento RuralUniversidade Eduardo MondlaneVilankuloRepública de Mocambique

Secondary Miombo woodlands and forest plantations occupy increasing areas in Mozambique,the former due to anthropogenic ***,mainly species of eucalyptus and Pinus,are being established on sites previously covered by secondary Miombo *** affects the evolution,cycle and spatiotemporal patterns of carbon(C)storage and stocks in forest *** estimation of C storage,which is indispensable for formulating climate change policies on sequestrating CO_(2),requires tools such as biomass models and biomass conversion and expansion factors(BCeF).In Mozambique,these tools are needed for both indigenous forests and *** objective of this study is to fit species-specific allometric biomass models and BCeF for exotic and indigenous tree *** incorporate efficient inter-species variability,biomass equations were fitted using nonlinear mixed-effects *** tree component biomass models had good predictability;however,better predictive accuracy and ability was observed for the 2-predictors biomass model with tree height as a second *** majority of the variability in BCeF was explained by the variation in tree *** species had larger crown biomass per unit of stem diameter and stored larger amounts of biomass per stem ***,due to relatively rapid growth,larger stem diameters,heights,and stand density,the plantations stored more biomass per tree and per unit area.

关键词： Biomass allometry Biomass partitioning Miombo exotic forest plantations Brachystegia spiciformis Julbernardia globifl ora eucalyptus Pinus

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Population structure of Araucaria angustifolia under distinct forest protection status:implications for management and conservation

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Journal of Forestry Research 2023年第5期34卷 1437-1446页

作者： Vinicius Costa Cysneiros Allan Libanio Pelissari Sylvio Pellico Netto Sebastiao do Amaral Machado Afonso Figueiredo Filho departamento de Agricultura Biodiversidade e FlorestasUniversidade Federal de Santa Catarina-UFSCRodovia Ulysses GaboardiKm 03CuritibanosSC 89520-000Brazil departamento de Ciencias Florestais Universidade Federal do Paraná-UFPRAv.Prof.Lothario Meissner632CuritibaPR 80210-170Brazil departamento de engenharia Florestal Universidade Estadual do Centro-Oeste-UNICENTROPR-153Km 7IratiPR 84500-000Brazil

Araucaria angustifolia is the dominant coniferous species in Brazil,a long-lived pioneer species and a supplier of valuable timber and non-timber products,which gives it key-species *** study examines how *** population structure affects the stand structure,and whether these relationships differ between protected and unprotected *** study was carried out on two protection status forests(national forest and urban forest)in a region of Atlantic mixed forest in ParanáState,southern *** coefficient and the Weibull shape parameter described the population structure and its effects on species diversity and biomass *** diameter distribution differed significantly between forests,with unbalanced structure in both,although regeneration was more abundant in the protected *** positively affected aboveground biomass whereas shape negatively affected it and species *** relationships differed between protected and unprotected *** effect of *** populations on stand structure was conditioned on protection ***-growth populations may have lower diversity and biomass stock even supporting large ***,old-growth forests,can lead to wood loss through mortality,senescence,and declining populations,representing the waste of a valuable timber *** findings provide useful knowledge for forest management,species conservation,and the carbon market.

关键词： Key species Diameter distribution Weibull shape parameter Aboveground biomass

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