Heavy Fraction
Mostrando 1-12 de 200 artigos, teses e dissertações.
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1. A review of common parameters and descriptors used in studies of the impacts of heavy metal pollution on marine macroalgae: identification of knowledge gaps and future needs
ABSTRACT This study presents a systematic review to assess the main similarities and gaps in efforts to evaluate the impacts of heavy metals on benthic marine seaweeds. A total of 91 studies were compiled, the main parameters (abiotic, biological, ecotoxicological, and heavy metals) and descriptors of which were evaluated by quantitative and qualitative ana
Acta Bot. Bras.. Publicado em: 2020-09
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2. Recent Developments on the Elucidation of Colloidal Aspects of Asphaltenes and Their Relevance to Oilfield Problems
Asphaltenes constitute the heavy petroleum fraction responsible for deposition events that may lead to reduced oil production, therefore of great interest for flow assurance. These molecules self-assemble in solutions leading to formation of aggregates that eventually grow towards precipitation and blockages in reservoirs and pipelines. Based on the Yen-Mull
J. Braz. Chem. Soc.. Publicado em: 2020-02
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3. Pre-concentration potential evaluation for a silicate zinc ore by density and sensor-based sorting methods
Abstract Pre-concentration consists of the preliminary discarding of a fraction of the mineral processing plant feed which contains little or none of the mineral of interest, reducing the mass to be processed in downstream operations (e.g. milling, concentration and dewatering), as well as the capital and operational costs. In this context, this study invest
REM, Int. Eng. J.. Publicado em: 2019-06
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4. Black Carbon Associated to PM1.0 and PM2.5: Mass Variation due to Combustion of Biodiesel/Diesel Blends (B5, B6, B7 and B8)
The present study aims to quantify black carbon (BC), particulate matter (PM1.0 and PM2.5, particles with diameter ≤ 1.0 and 2.5 µm, respectively) levels and their variability during the combustion of biodiesel/diesel blends used in heavy-duty vehicles. The samplings were conducted in the years 2014, 2016 and 2017 inside a semi closed bus station, a direc
J. Braz. Chem. Soc.. Publicado em: 2019-04
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5. Radiotherapy and immune response: the systemic effects of a local treatment
Technological developments have allowed improvements in radiotherapy delivery, with higher precision and better sparing of normal tissue. For many years, it has been well known that ionizing radiation has not only local action but also systemic effects by triggering many molecular signaling pathways. There is still a lack of knowledge of this issue. This rev
Clinics. Publicado em: 10/12/2018
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6. Alterations in the expression and activity of extracellular matrix components in HPV-associated infections and diseases
Infection with human papillomaviruses is associated with a series of benign and malignant hyperproliferative diseases that impose a heavy burden on human populations. A subgroup of mucosal human papillomavirus types are associated with the majority of cervical cancers and a relevant fraction of vulvar, vaginal, anal, penile and head and neck carcinomas. Huma
Clinics. Publicado em: 06/09/2018
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7. In vitro Evaluation of Oxidative Stress Caused by Fine Particles (PM2.5) Exhausted from Heavy-Duty Vehicles Using Diesel/Biodiesel Blends under Real World Conditions
In this work, the redox activity of fine diesel/biodiesel particulate matter (PM2.5) was studied in order to approach its toxicity from reactive oxygen species, due to adverse effects it may cause to human health. The oxidative potential was measured by the dithiothreitol (DTT) assay in order to study the relative contribution of water-soluble transition met
J. Braz. Chem. Soc.. Publicado em: 2018-06
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8. Metal-Resistant Rhizobacteria Change Soluble-Exchangeable Fraction in Multi-Metal-Contaminated Soil Samples
ABSTRACT There is a complex interaction between various components of the soil ecosystem, including microbial biomass and soil chemical contaminants such as heavy metals and radionuclides, which may greatly affect the efficiency of bioremediation techniques. The aim of this study was to investigate microbial capacity to change pH, changes in the metal solubl
Rev. Bras. Ciênc. Solo. Publicado em: 29/03/2018
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9. AVALIAÇÃO DE ASFALTENOS PRECIPITADOS EM DIFERENTES CONDIÇÕES DE COMPOSIÇÃO, TEMPERATURA E PRESSÃO
Asphaltenes are a heavy fraction of petroleum with the ability for self-association, a phenomenon that can occur spontaneously in the reservoirs or in any of the various stages of production and processing, depending on variations in pressure, temperature, composition and shearing, among others. In this work, it was evaluated the precipitation of asphaltenes
Quím. Nova. Publicado em: 2018-02
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10. Effect of Mineral Nitrogen on Transfer of 13C-Carbon from Eucalyptus Harvest Residue Components to Soil Organic Matter Fractions
ABSTRACT The amount of harvest residues retained in Eucalyptus plantations strongly influences soil organic matter (SOM), but the efficiency of conversion to SOM may vary according to the type of residue. This study evaluated the recovery of C from Eucalyptus residue components - leaves, bark, branches, roots, and a mix of all residues - in different SOM fra
Rev. Bras. Ciênc. Solo. Publicado em: 31/07/2017
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11. Modelling of Lead Migration from Electronic Waste to Mixtures of Kaolinite, Iron Oxides and Organic Matter
Improper disposal of electronic waste in the environment facilitates migration of heavy metals, especially lead, into the soil and can contribute to the bioavailability of this species. Based on a simplex-centroid mixture experimental design, small-scale tests were performed for incubation of printed circuit boards (PCBs) in mixtures containing organic matte
J. Braz. Chem. Soc.. Publicado em: 2016-05
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12. INTERFACIAL ENERGY DURING THE EMULSIFICATION OF WATER-IN-HEAVY CRUDE OIL EMULSIONS
Abstract The aim of this study was to investigate the interfacial energy involved in the production of water-in-oil (W/O) emulsions composed of water and a Brazilian heavy crude oil. For such purpose an experimental set-up was developed to measure the different energy terms involved in the emulsification process. W/O emulsions containing different water volu
Braz. J. Chem. Eng.. Publicado em: 2015-03