Search results for "Chemical engineering"
showing 10 items of 5892 documents
Divided Wall Column Modeling and Simulation in an Open-Source Environment
2020
The divided wall column (DWC) can achieve sharp separations of three or more components in a single shell, substituting conventional sequences of two or more binary distillation columns, with lower expenses. Despite these advantages, DWC models are not available in commercial chemical process simulators. To simulate DWC, users must employ instances of conventional column model and couple them in different configurations. In this paper, a DWC model was developed in EMSO (Environment for Modeling, Simulation and Optimization). DWC model was then used for simulating the separation of an equimolar mixture of three hydrocarbons. Results show that, depending on the number of trays, DWC presented …
Innovación educativa para integrar la seguridad en asignaturas experimentales
2014
La formación es uno de los pilares esenciales para consolidar una auténtica cultura de la prevención que luego repercuta en el ámbito laboral. En Ingeniería Química, la formación en Higiene y Seguridad es absolutamente necesaria, por el tipo de equipos y productos manejados. Sin embargo, la integración de la prevención de riesgos en los nuevos planes de estudio de Ingeniería Química es muy variable, y todavía insuficiente para que los egresados estén capacitados para desarrollar su actividad profesional aplicando los principios de la prevención de riesgos. Aprovechando la puesta en marcha de los nuevos grados, se pensó desarrollar alguna estrategia para mejorar la formación en Seguridad de …
Metall-π-Komplexe von Benzolderivaten, XII Hyperfeinstruktur und Linienbreiten in den ESR-Spektren methylierter und deuterierter Bis(η-benzol)chrom(I…
1979
Die vollstandige Reihe der Methyl-Substitutionsprodukte des Bis(η-benzol)chrom(I)+·-Radikalkations sowie ausgewahlte deuterierte Derivate desselben wurden in Losung und in glasartig erstarrtem Medium ESR-spektroskopisch untersucht. 1H-, 2D- und 53Cr-Hyperfeinparameter werden mitgeteilt und das Proton/Deuteron-Kopplungskonstantenverhaltnis wird diskutiert. Die Betrage von a(1HAren) und a(1HMethyl) variieren innerhalb enger Grenzen (3,454,15 bzw. 0,50,7 G), wobei a(1HAren) mit zunehmendem Methylierungsgrad zunimmt. Um die Konformationsabhangigkeit von a(1HMethyl) zu studieren, werden die ESR-Spektren von (η12-[2.2]Paracyclophan)-chrom(I)+·, 21+·, und Bis(1,4-dimethyl-η6-benzol)chrom(I)+·, 5+·…
Valores personales y autoestima en población general y clínica
2008
The aim of this study is to investigate the association between personal values and self-esteem in general population and clinical population. The sample was composed of a group of patients with a diagnosis of anxiety disorders and/or depression (n = 60) and a comparison group, paired by sex and age, of general population (n = 60). The Portrait Values Questionnaire of Schwartz (PVQ) and the Autoe Self-esteem Scale were used. T-tests were performed to compare the scores of both instruments between the two groups. The clinical sample scored significantly lower in Self-esteem, Self- direction, Hedonism, and Openness to Change. For this reason, Pearson correlations were calculated in differenti…
La inteligencia de los niños
2005
Partial results of an investigation are presented whose primary objective is to adapt and to standardize the neurocognitive assessment battery C.A.S. of Das and Naglieri (1997) in a child sample. The test is an operationalization of a non traditional intelligence model (PASS) that considers the intelligent behaviors as a group of four cognitive basic processes (planning, attention, simultaneous and successive processing). The objectives of this work are to obtain the psychometric properties of the instrument and also, to analyze if differences exist according to sex and age. The study type is crosswise - transactional. It was administered the CAS to 150 children residents in Buenos Aires am…
Phosphotungstic acid (PTA) in the synthesis of 3D CdS superstructures by diffusion assisted hydrothermal method
2015
Abstract In this study, the synthesis of cadmium sulfide (CdS) microstructures by gas diffusion assisted hydrothermal method using phosphotungstic acid (PTA) is reported. The as-synthesized products were characterized by Fourier transform infrared (FTIR), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of PTA dose, thioacetamide amount, time and temperature on the morphology of obtained particles have been studied. In this process, PTA ion host stabilizes the CdS particles against aggregation and thioacetamide plays two roles, being at the same time a sulfur source and a capping ligand. Based on the performed analyses it seems that the thioacetamide is mor…
Application of Electronic Nose for Evaluation of Wastewater Treatment Process Effects at Full-Scale WWTP
2019
This paper presents the results of studies aiming at the assessment and classification of wastewater using an electronic nose. During the experiment, an attempt was made to classify the medium based on an analysis of signals from a gas sensor array, the intensity of which depended on the levels of volatile compounds in the headspace gas mixture above the wastewater table. The research involved samples collected from the mechanical and biological treatment devices of a full-scale wastewater treatment plant (WWTP), as well as wastewater analysis. The measurements were carried out with a metal-oxide-semiconductor (MOS) gas sensor array, when coupled with a computing unit (e.g., a computer with…
Influence of Polymer Electrospun Nanofibers on Thermal Properties of Epoxy Resins
2019
Electrospinning of polymers has gained surging interest in the last decades due to its wide range of applications in different fields, such as sensors, electronic devices, separation systems, biomedical materials. Still there are only few reports on the use of these nanofibers as reinforcement in polymer composites. In this paper, solution electrospinning was employed to produce nanofibrous mats impregnating two epoxy resins to form “monolayer“ systems, with the aim to study the influence of the nanofibers on both the curing behaviour and the morphology of the resin systems. Three polymers were chosen for producing electrospun mats, a polysulfone (PSF), a polyamide Nylon 6,6 (Ny66) and a po…
Biochar from Waste Derived Fuels as Low-Cost Adsorbent for Waste Hydrocarbons
2020
Abstract The aim of this study is to prove technical feasibility of combined refuse derived fuel (RDF) torrefaction and oily wastewater treatment approach by using RDF derived biochar as a sorption media. Biochars prepared from refuse derived fuels in torrefaction, carbonization and pyrolysis modes were analysed as fuels and as hydrocarbon sorbents. Changes of elemental composition and properties of material during thermal treatment and subsequent washing process have been analysed. Experimental evaluation of sorption behaviour of toluene and diesel fuel on obtained biochar performed. Our results show that torrefaction/carbonization of RDF coupled with the subsequent washing of biochar is a…
Caffeine analysis and extraction from a topical cream intended for UV-skin protection
2020
Made available in DSpace on 2021-06-25T10:16:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 This study aimed to develop and validate a method for the analysis of caffeine in complex cosmetic samples, such as sunscreens. Besides, an extraction method of caffeine from coffee oil and from creams, which contains both lipophilic and hydrophilic components, has been developed. The method to analyze caffeine was developed using an isocratic pump, Waters 1515 and an automatic injector Perkin-Elmer Series 200 and an UV detector Perkin-Elmer. As stationary phase, Kromasil C-18 (150 × 4.6 mm ID with particle size of 5 µm) column was used and a mixture of water (pH 4.00)/acetonitrile (…