Chemical Study
Mostrando 1-12 de 5214 artigos, teses e dissertações.
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1. Influence of Refinery Asphalt Residue Addition on Flow: A Study Using Waxy Model-System
One of the main phenomena causing problems in the oil industry is the precipitation of waxes, which can crystallize and form deposits, clogging lines and reducing flows. Many studies have been conducted seeking to overcome this problem, mainly through application of chemical to increase flow. Some studies have shown that the asphaltenes present in crude oil
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Study of Catalytic Pyrolysis of Biomass Sorghum (Sorghum bicolor L. Moench) Using Design of Experiments and Surface Response Methodology
This study proposes a screen of variables that have an influence on the modification of the bio-oil chemical composition as a unique critical quality attribute (CQA) throughout the pyrolytic process (zeolite, ZSM-5) by using a 24 full factorial design, followed by optimization through a response surface methodology (RSM) based on central composite design (CC
Journal of the Brazilian Chemical Society. Publicado em: 2023
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3. The influence of compositional variability of dimension stone residues on the properties of rustic porous ceramic tiles
Abstract This study analyzed how the compositional variability of dimension stone residues influences the characteristics of rustic porous ceramic tiles. The specimens were prepared by adding 20 wt% of dimension stone residue to the clay and sintered at 1000 °C for 1 h. The testing assays performed were physical properties and structural analysis through sc
Cerâmica. Publicado em: 2023
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4. Effects of chemical straighteners on the hair shaft and scalp
Abstract Background The effects of chemical straighteners on the scalp and hair shaft are not fully known, although such substances are widely used. Hair straightening became popular in Brazil with the use of formaldehyde and its derivatives, despite the prohibition by the current legislation. Objective To identify changes in hair shaft and scalp caused by
Anais Brasileiros de Dermatologia. Publicado em: 2022
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5. How Much do the Environmental Conditions Interfere with the Essential Oils of Eugenia spp. L. (Myrtaceae)?
Eugenia is the largest neotropical genus in the Myrtaceae family. The genus has a wide geographical distribution, occurring from Mexico to Argentina. Eugenia species are rich in essential oils. Essential oils have applications in perfumery, cosmetics, food, pesticides and medicines. Several factors can influence the chemical composition and yield of essentia
Journal of the Brazilian Chemical Society. Publicado em: 2022
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6. Development and Chemical Characterization of Pequi Pericarp Flour (Caryocar brasiliense Camb.) and Effect of in vitro Digestibility on the Bioaccessibility of Phenolic Compounds
The pequi pericarp corresponds to the largest portion of the fruit and has a high nutritional value, but it is discarded as an agro-industrial residue. The present study aimed to prepare and characterize flours from the pequi pericarp in terms of their proximate composition, its antioxidant potential before and after the in vitro digestibility process and ch
Journal of the Brazilian Chemical Society. Publicado em: 2022
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7. Carbon and Nitrogen Stocks Under Different Land-Use in the Paraopeba River Basin-MG Before the Corrégo do Feijão Dam Burst
ABSTRACT Soil attributes can provide indicators for the management and conservation of natural and agrarian ecosystems. This study was carried out before the rupture of the Córrego do Feijão dam and aimed to evaluate and quantify the stocks of carbon, nitrogen and the C/N ratio in soils around the Paraopeba-MG river basin in five regions corresponding to t
Revista Ceres. Publicado em: 2022
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8. Evaluation of the use of blast furnace slag as an additive in mortars
Abstract Clinker is the raw material used in the manufacture of cement. However, this material is very harmful to the environment, since it is estimated that for every ton of clinker produced, about 1.0 ton of CO2 is released into the atmosphere. For this reason, alternatives were sought for the use of other materials that are less harmful to the environment
REM - International Engineering Journal. Publicado em: 2022
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9. A New Synthetic Route and Comprehensive Topological Study of a Benzimidazole Derivative
Benzimidazole and its derivatives are molecules that have diverse biological properties, therefore we synthesized and studied a new benzimidazole to understand their physical/chemical properties. The compound was obtained through a new synthetic route, using graphite oxide, in the absence of solvent, with crystalline packaging supported by C-H…N and C-H…
Journal of the Brazilian Chemical Society. Publicado em: 2022
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10. Influence of the addition of niobium oxide on the properties of fused aluminum oxide used in abrasive tools
Abstract Fused alumina is a material used in the manufacturing of abrasive tools, due to its high fusion point, great hardness, and mechanical toughness. In this context, this study addressed the influence of niobium addition on the properties of fused alumina for abrasive applications. A comparison was also made between this oxide and the brown fused alumin
Cerâmica. Publicado em: 2022
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11. Ultrafine quartz flocculation: Part I. System characterization and variables selection
Abstract A characterization study was performed to verify the more relevant physicochemical properties for quartz flocculation with polyacrylamide, as well as to define which variables should be further investigated regarding this flocculation system. Polyacrylamide was evaluated through molecular weight, radius of gyration, and infrared spectrometry. A natu
REM - International Engineering Journal. Publicado em: 2022
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12. NMR Relaxometry Applied to Chemical Studies of Paramagnetic Metal Cation Complexes: Fundamentals and Applications
Low field time-domain nuclear magnetic resonance (TD-NMR) relaxometry of paramagnetic metal cations (PMC) has been widely used to study and improve contrast agents for magnetic resonance imaging (MRI). However, despite its remarkable potential, TD-NMR is rarely used to study PMC complexes, and coordination compounds in non-biomedical application. Therefore,
Journal of the Brazilian Chemical Society. Publicado em: 2022