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Search Results: 1 - 10 of 213344 matches for " Maria Helena;K?mpf "
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Densidade de substratos dependendo dos métodos de análise e níveis de umidade
Fermino, Maria Helena;Kmpf, Atelene N;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000100013
Abstract: the term "substrate for plants" refers to the growth medium used in cultivation in containers, often resulting from the mixture of materials. the final quality depends on the physical and chemical attributes of each component and the interaction among them, which need to be characterized. although the reference works are unanimous including volumetric density for substrate characterization, the interpretation of reports from different laboratories is difficult, because they use different methods or variations of the same method. in addition to the differences between methods, there might be other causes of variation in the achievement of results from a single sample. this work aims to demonstrate two of the causes of variation in the determination of density by volume: 1) the method of analysis [method of double ring (cen), the method used by the industry (ind) and method of auto compact (auto) of substrate dust] of coconut, washed sand of river, peat brown in natura and plantmax? for horticulture; 2) and the initial level of humidity (0.62, 0.69 and 0.72 g/g) in in natura samples of peat brown. the density values, determined by the auto, represented about 20% more than the values determined by ind; relations between the auto and cen methods as well as cen and ind were not uniform, depending on the material. initial moisture of the sample also represents the cause of variation in the results.
On the performance of capillary barriers as landfill cover
M. Kmpf,H. Montenegro
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 1997,
Abstract: Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m). In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.
The circulation of the Persian Gulf: a numerical study
J. Kmpf,M. Sadrinasab
Ocean Science (OS) & Discussions (OSD) , 2006,
Abstract: We employ a three-dimensional hydrodynamic model (COHERENS) in a fully prognostic mode to study the circulation and water mass properties of the Persian Gulf – a large inverse estuary. Our findings, which are in good agreement with observational evidence, suggest that the Persian Gulf experiences a distinct seasonal cycle in which a gulf-wide cyclonic overturning circulation establishes in spring and summer, but this disintegrates into mesoscale eddies in autumn and winter. Establishment of the gulf-wide circulation coincides with establishment of thermal stratification and strengthening of the baroclinic exchange circulation through the Strait of Hormuz. Winter cooling of extreme saline (>45) water in shallow regions along the coast of United Arab Emirates is a major driver of this baroclinic circulation.
The circulation of the Persian Gulf: a numerical study
J. Kmpf,M. Sadrinasab
Ocean Science Discussions (OSD) , 2005,
Abstract: We employ a three-dimensional hydrodynamic model (COHERENS) to study the circulation and water mass properties of the Persian Gulf, which is a large inverse estuary. Our findings suggest that the Persian Gulf experiences a distinct seasonal cycle in which a Gulf-wide cyclonic overturning circulation establishes in spring and summer, but this disintegrates into mesoscale eddies in autumn and winter. Establishment of the Gulf-wide circulation coincides with establishment of thermal stratification and strengthening of the baroclinic exchange circulation through the Strait of Hormuz. The latter is associated with winter cooling of extreme saline (>45 psu) water in shallow regions along the coast of United Arab Emirates. To validate the model results, we present a detailed comparison with observational evidence.
Variabilidade de goethita e hematita via dissolu??o redutiva em solos de regi?o tropical e subtropical
Inda Junior, Alberto Vasconcellos;Kmpf, Nestor;
Revista Brasileira de Ciência do Solo , 2005, DOI: 10.1590/S0100-06832005000600003
Abstract: iron oxides from 22 soil samples (19 from argillic b horizons; one from a plinthic b horizon; one from a cambic horizon and one from a c horizon) were subjected to selective dissolution with sodium dithionite-citrate-bicarbonate at 20 oc in time intervals of 5 to 3,840 minutes. mean coherence lengths (mcl), specific surface area (ssa) and iron by aluminum substitution (al3+-substitution) of goethite and hematite in untreated sub-samples and in selected sub-samples treated during selective dissolution were estimated by x ray diffraction analysis (xrd). the control of remaining goethite and hematite phases after each time interval of selective dissolution was carried out by differential x ray diffraction (dxrd). the crystal dissolution kinetics was described by segmentation of the iron dissolution curve as a time function at the intervals where dissolution occurred linearly. dissolution rates of each linear segment were obtained by the angular coefficient of the straight line of each linear segment. in the latossolic goethitic samples, this methodology discriminated different phases of goethite (heterogeons populations) regarding al3+-substitution, mcl and ssa, making possible to classify goethite stability degrees (low, medium, high, and very high stability). goethite samples from young pedogenic environments and latossolic hematitic samples were characterized by higher crystal homogeneity, which were classified as being of low and medium stability. in goethitic samples, crystal proportion with high stability (high al3+-substitution and crystallinity) in each population showed positive association with gibbisite proportion compared to caulinite in the samples. hematite presented lower stability to dissolution reduction than goethite, except in goethite samples with low al3+-substitution and low ase. the characterization of heterogeneous goethite populations can increase the use of this oxide as indicator of pedogenic processes and contribute to a better understanding
Avalia??o de procedimentos de extra??o dos óxidos de ferro pedogênicos com ditionito-citrato-bicarbonato de sódio
Inda Junior, A. V.;Kmpf, N.;
Revista Brasileira de Ciência do Solo , 2003, DOI: 10.1590/S0100-06832003000600018
Abstract: pedogenic iron oxides (fed) were quantified in 22 hematitic and goethitic soil samples (19 from oxic horizons; one from a plinthic horizon; one from a cambic horizon; one from saprolite) by use of two extraction procedures with sodium dithionite-citrate-bicarbonate (dcb). approximately ninety percent of the fed content was extracted at the first extraction by the dcb80 procedure. this procedure was more effective at extracting fed than the dcb20, whose efficiency decreased with increasing al3+-substitution in goethite. compared with the drx analysis, al3+-substitution in goethite determined by the dcb80 procedure was superestimated. maghemite masked al3+-substitution estimates in hematite from hematitic samples.
Avalia o de procedimentos de extra o dos óxidos de ferro pedogênicos com ditionito-citrato-bicarbonato de sódio
Inda Junior A. V.,Kmpf N.
Revista Brasileira de Ciência do Solo , 2003,
Abstract: Em 20 amostras hematíticas e goethíticas de horizontes B latossólicos, uma de B plíntico, uma de B incipiente e uma de saprolito, foram avaliados dois procedimentos de extra o de óxidos de ferro pedogênicos (Fe d) por ditionito-citrato-bicarbonato de sódio (DCB). O procedimento a 80 oC (DCB80) extraiu aproximadamente 90 % do Fe d na primeira extra o e praticamente a totalidade do mesmo na segunda extra o, sendo mais efetivo que o procedimento a temperatura ambiente (DCB20), o qual teve sua eficiência reduzida com o aumento da substitui o isomórfica de Fe3+ por Al3+ na goethita. A substitui o isomórfica de Fe3+ por Al3+ na goethita determinada por DCB80 superestimou os valores determinados por DRX conforme aumentaram as extra es. Em amostras hematíticas, esta estimativa foi prejudicada pela presen a de maghemita que dissolveu juntamente com a hematita.
Análise microbiológica de ossos de c?es conservados por longo período de tempo na glicerina a 98% à temperatura ambiente, objetivando a extertia óssea
Gioso, Marco Antonio;Benites, Nilson Roberti;Kmpf, Gabriela;
Acta Cirurgica Brasileira , 2002, DOI: 10.1590/S0102-86502002000400008
Abstract: objective: verify the microorganism growth in bone plus glycerin samples stocked for at least nine years. methods: microbiology analisys of epiphisis and bone marrow stocked at glycerin 98% was done. results: no statistically significant growth was verified. conclusion: this result means that glycerin is an excellent bone conservation substance for long periods of stockage.
Concentra??o de sacarose no enraizamento in vitro de morangueiro
Calvete, Eunice Oliveira;Kmpf, Atelene Normann;Suzin, Marilei;
Horticultura Brasileira , 2002, DOI: 10.1590/S0102-05362002000200014
Abstract: the vegetative propagation of strawberry plants allows dissemination of plant pathogens when infected plants are used. to avoid such pathogen transmission, especially viruses, plant merystem growing in vitro is usual. transfer of micropropagated seedlings to ex vitro conditions, however, is a delicate process. successful plant adaptation to ambient depends on optimum growing conditions including the rooting phase. this research was conducted at the universidade federal do rio grande do sul and universidade de passo fundo (brazil). the effect of sucrose concentration was quantified in the culture medium over rooting of strawberry plants. seedlings of cv. campinas were selected during multiplication and transferred to an "ms" (murashige & skoog) basic medium amended with bap (0.005 mg l-1) and different sucrose amounts (0; 15; 30; 45, and 60 g l-1). the experimental units were arranged according to a randomized block design with nine replicates, each replicate being a pot with five plants. the fresh and dry weight of leaves and roots were determined and used to calculate the content of water in plant tissues. while lack of sucrose resulted in no rooting, the concentration of 45 g l-1 provided the best root growth. therefore, campinas strawberry seedlings showed low photosynthetic capacity, behaving as mixotrophic or heterotrophic plants.
Propaga??o in vitro de Limonium latifolium Kuntze (Plumbaginaceae)
Fior, Claudimar Sidnei;Rodrigues, Lia Rosane;Kmpf, Atelene Normann;
Ciência Rural , 2000, DOI: 10.1590/S0103-84782000000400003
Abstract: limonium latifolium kuntze is a cut flower commercialy propagated in vitro. to develop and improve the micropropagation protocol, a sequence of assays was developed to evaluate performance of node explants; effect of cytokinins concentration (kinetin-kln and 6-benzyl-aminopurin-ba) on the regeneration rate; the presence of ba during the multiplication phase; concentration of naphthaleneacetic acid-naa and indole3-butyric acid-iba on the rooting phase and procederes for the acciimatiwtion in vitro. the micropropagation was done at commercial levei using inflorescence nades explants. by the regeneration phase the best results were obtained with ba at 0.7mg/l for 35 days in ms médium. the multiplication phase takes 35 days and shows satisfactory results with ba at 0.2mg/l , with the rate of 4 plantiets/explant. the rooting phase is takes 30 days in ms medium with iba at 1mg/l , with good survival scores after transfer to in vivo. the acciimatiwtion hás made under plastic covering, inside greenhouse with room temperature and intermitent mist, using flats with 242 cells of 10cm3 each, filled with sterilized carbonized rice hulis. every two weeks the plants were fertigated with commercial fertilizer (15:5:15 + micronutrients) at 0.5g/l . the in vitro process takes 100 - 120 days and one explant originates 15 - 30 plants.
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