Columns
Mostrando 1-12 de 1628 artigos, teses e dissertações.
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1. Optimum design of steel columns filled with concrete via genetic algorithm: environmental impact and cost analysis
Abstract The use of concrete-filled tubular columns as part of structural systems has steadily increased throughout the years. The growing demand for structural elements of this nature is a direct result of the possibility to use various cross-section shapes that have increased strength, along with resistance to fire and other corrosive agents. The main obje
REM - International Engineering Journal. Publicado em: 2022
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2. Development and application of a test mixture for untargeted liquid chromatography-mass spectrometry analysis of urine samples
Metabolic profiling of complex biological matrices based on liquid chromatography-mass spectrometry (LC-MS) allows detecting a wide range of metabolites with distinct concentrations and physicochemical properties. Given the complexity of samples and the necessity of a comprehensive approach in untargeted metabolomics, quality control strategies are mandatory
Química Nova. Publicado em: 2022
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3. Numerical analysis of soft soil improved with stone column technique
Abstract The present research aims to do a numerical study on the behavior of a test embankment reinforced with stone column spacing of 1.85 m in a square grid with an average diameter of 1.0 m and 11.35 m length. The case study investigated the work in a steel company (ThyssenKrupp), located in Santa Cruz, western region of Rio de Janeiro - Brazil, where a
REM, Int. Eng. J.. Publicado em: 2021-09
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4. A Systematic Pipeline to Enhance the Fecal Metabolome Coverage by LC-HRMS
The comprehended knowledge of the metabolic profile of the fecal matter has been recognized as an important point for understanding metabolic changes in the human systemic metabolism and it can provide precious information about host-gut microbiota interactions. However, few analytical strategies have been addressed for a broad analysis of metabolites with d
J. Braz. Chem. Soc.. Publicado em: 2021-07
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5. Clarifying the theoretical basis of the global geometric imperfection analysis (out-of-plumb columns)
Abstract The concrete structures present several geometric deviations, some of them considered indirectly in the safety factors of the design. However, the imperfections of the element axes, especially columns, should be explicitly considered in the structural analysis because they have great influence over the building stability. The NBR 6118:2014, Brazilia
REM, Int. Eng. J.. Publicado em: 2021-06
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6. An Online Solid Phase Extraction-Liquid Chromatography Tandem Mass Spectrometry Method for the Analysis of Parabens in Urban Waters
In this work, we report a method to quantify methylparaben, ethylparaben, propylparaben and butylparaben in urban waters of São Carlos (São Paulo State, Brazil) by online solid phase extraction-liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) system. The method achieved ng L-1 limits with good accuracy and precision (internal standards for eac
J. Braz. Chem. Soc.. Publicado em: 2021-05
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7. Blue Glow Sticks: Cinnamic Acids and Arylacrylonitriles with Liquid-Crystalline Properties and Highly Fluorescent
Five new π-conjugated chromophores derived from acrylic acid and acrylonitrile were synthesized and their thermal and photophysical behaviors were analyzed. They were designed and synthesized through Knoevenagel condensations between arylacetylenebenzaldehydes and a methylene group activated from cyanoacetic and malonic acids. The characterization of the ta
J. Braz. Chem. Soc.. Publicado em: 2021-01
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8. Microstructural and mechanical characterisation of the Simon Bolivar's iron bridge structure, 19th century, Arequipa, Peru
Abstract The microstructure of the main structural elements (Phoenix columns, transversal beams and tie-rods) of the Simón Bolivar iron bridge, located in Arequipa (Peru), was investigated. The bridge was supposedly designed by Gustave Eiffel and opened to the public in 1882. The characterisation revealed that the columns, beams and tie-rods are made of pud
REM, Int. Eng. J.. Publicado em: 2020-12
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9. Potential Slow Release Fertilizers Based on K2MgSiO4 Obtained from Serpentinite
In this work, a potassium magnesium silicate mineral based on phase K2MgSiO4 was prepared from serpentinite rock and studied as a potential K and Mg slow-release fertilizer. The material was prepared by impregnation of serpentinite/KOH and calcination at 700 °C to produce K2MgSiO4 phase, olivine and forsterite. The release patterns of K and Mg in the stirre
J. Braz. Chem. Soc.. Publicado em: 2020-04
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10. PHYSICAL AND THERMAL PROPERTIES OF EUCALYPTUS WOOD CHARCOAL.
ABSTRACT The knowledge of the physical and thermal properties of eucalyptus charcoal is of fundamental importance in the design of equipment and development of cooling technologies. However, literature about physical properties for eucalyptus wood charcoal is largely unavailable, especially the thermal and aerodynamic properties, for the same material. The a
CERNE. Publicado em: 2020-03
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11. Avaliação de matéria orgânica, densidade e porosidade do latossolo vermelho em contato com lixiviado de resíduos sólidos urbanos
RESUMO O objetivo do trabalho é avaliar a densidade, a porosidade e a matéria orgânica do solo decorrentes da interação solo-lixiviado em um latossolo vermelho, em duas profundidades: 0,2 e 1,5 m. As amostras de solo foram coletadas indeformadas, e o lixiviado em aterro foi controlado. Utilizaram-se colunas de difusão, sem fluxo, onde o solo ficou subm
Eng. Sanit. Ambient.. Publicado em: 20/12/2019
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12. ENERGY AND EXERGETIC EVALUATION OF THE MULTICOMPONENT SEPARATION OF PETROCHEMICAL NAPHTHA IN FALLING FILM DISTILLATION COLUMNS
Abstract Multicomponent separation of synthetic petrochemical naphtha (hexane, cyclohexane, toluene and xylene) was carried out in a falling film distillation sequence with heat supply using a vapor chamber (thermosyphon). Tests were carried out by varying feed flow rate and temperatures of the feed and the vapor chamber in two ways of heat supply: isotherma
Braz. J. Chem. Eng.. Publicado em: 09/12/2019