Equilíbrio líquido-líquido para o sistema biodiesel de óleo de semente de melão (Cucumis melo l.) + metanol + glicerina

Rio Grande do Norte, northeast state from Brazil, it is the greatest producer and exporter of yellow melon, well known as Spanish melon. Despite the consumption of this fruit to be mainly its pulp, melon seeds are an important source of lipids considered an industrial residue it has been discharge product. The use of oilseeds in order to produce biodiesel establishes an important raw material and the increase of its production promotes the national development of the agriculture. In this background, the aim of this work has been to use oil from seeds of yellow melon to produce biodiesel and to accomplish a study of the phase equilibrium of the system evolving biodiesel, methanol and glycerin. The biodiesel was obtained by oil transesterification through methylic route with molar ratio 1:9.7 (oil:alcohol) and with a mass of NaOH of 0.5% from the oil mass; the reaction time was 73 minutes at 55 °C. A yield of 84.94% in biodiesel was achieved. The equilibria data present a well-characterized behavior with a great region of two phases. The tie lines indicate that methanol has a best solubility in the phase that is rich in glycerin. Consistency of the experimental data was made based on Othmer-Tobias and Hand correlations which values above 0.99 were found to correlation coefficients, this fact confers a good thermodynamic consistency to the experimental data. NRTL and UNIQUAC models were employed to predict liquid-liquid equilibrium of this system. It was observed a better concordance of the results when NRTL was applied (standard deviation 1.25%) although the UNIQUAC model has presented a quite satisfactory result either (standard deviation 2.70%). The NRTL and UNIQUAC models were also used to evaluate the effect of temperature in the range of 328 K to 358 K, in which a little change in solubility with respect to the data obtained at 298 K was observed, thus being considered negligible the effect of temperature

Obtenção de Propriedades Físico-Químicas de Misturas de Hidrocarbonetos em Baixa e Alta Pressão Visando a Caracterização e a Modelagem

The composition of petroleum may change from well to well and its resulting characteristics influence significantly the refine products. Therefore, it is important to characterize the oil in order to know its properties and send it adequately for processing. Since petroleum is a multicomponent mixture, the use of synthetic mixtures that are representative of oil fractions provides a better understand of the real mixture behavior. One way for characterization is usually obtained through correlation of physico-chemical properties of easy measurement, such as density, specific gravity, viscosity, and refractive index. In this work new measurements were obtained for density, specific gravity, viscosity, and refractive index of the following binary mixtures: n-heptane + hexadecane, cyclohexane + hexadecane, and benzene + hexadecane. These measurements were accomplished at low pressure and temperatures in the range 288.15 K to 310.95 K. These data were applied in the development of a new method of oil characterization. Furthermore, a series of measurements of density at high pressure and temperature of the binary mixture cyclohexane + n-hexadecane were performed. The ranges of pressure and temperature were 6.895 to 62.053 MPa and 318.15 to 413.15 K, respectively. Based on these experimental data of compressed liquid mixtures, a thermodynamic modeling was proposed using the Peng-Robinson equation of state (EOS). The EOS was modified with scaling of volume and a relatively reduced number of parameters were employed. The results were satisfactory demonstrating accuracy not only for density data, but also for isobaric thermal expansion and isothermal compressibility coefficients. This thesis aims to contribute in a scientific manner to the technological problem of refining heavy fractions of oil. This problem was treated in two steps, i.e., characterization and search of the processes that can produce streams with economical interest, such as solvent extraction at high pressure and temperature. In order to determine phase equilibrium data in these conditions, conceptual projects of two new experimental apparatus were developed. These devices consist of cells of variable volume together with a analytical static device. Therefore, this thesis contributed with the subject of characterization of hydrocarbons mixtures and with development of equilibrium cells operating at high pressure and temperature. These contributions are focused on the technological problem of refining heavy oil fractions

Pyrolysis and combustion of pulp mill lime sludge

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

High-performance liquid chromatographic determination of amfepramone hydrochloride, mazindol, and diazepam in tablets

Simple and rapid procedures were developed for the quantification of amfepramone hydrochloride and diazepam and mazindol and diazepam in tablets using high performance liquid chromatography (HPLC) with UV detection. These techniques provided conditions for the separation of each active ingredient from the complex matrices of the dosage forms by dilution or extraction in methanol. Isocratic reversed phase chromatography was performed using acetonitrile, methanol, and aqueous 0,1% ammonium carbonate (70:10:20, v/v/v) as a mobile phase, Radial-Pak C-18 column (100 x 8 mm id, 4 mu m), a column temperature of 25+/-1 degrees C and detection at 255 nm. The calibration curves were linear over a wide concentration range (100-1000 mu g.mL(-1) to amfepramone hydrochloride and mazindol and 10-100 mu g.mL(-1) to diazepam) with good correlation factors of 0.9978, 0.9956 and 0.9997 for amfepramone hydrochloride, mazindol, and diazepam, respectively.Mean recoveries obtained from the two kinds of samples ranged from 83.2 to 102.5%, with coefficients of variation ranging from 1.0 to 6.1.These results demonstrated the efficiency of the proposed methods, as well as advantages such as simplicity and short duration of analysis.

Anelastic spectroscopy in a Ti alloy used as biomaterial

Ti and its alloys have been used thoroughly in the production of prostheses and dental implants due to their properties, such as high corrosion resistance, low elasticity modulus and high mechanical strength/density relation. Among the Ti-based alloys, the Ti-35Nb-7Zr-5Ta (TNZT) is one that presents the smallest elasticity modulus, making it an excellent alternative to be used as a biomaterial. In this paper, mechanical spectroscopy measurements were made in TNZT alloys containing several quantities of oxygen and nitrogen in solid solution. Mechanical spectroscopy measurements were made by using a torsion pendulum, operating at an oscillation frequency in the interval 4-30 Hz, temperature in the range 100-700 K, heating rate of about 1 K/min and vacuum lower than 10(-5) Torr. Complex relaxation structures and a reduction in the elasticity modulus were observed for the heat-treated and doped samples. The observed peaks were associated with the interactions of interstitial atoms and the alloy elements. (C) 2009 Elsevier B.V. All rights reserved.

Nitrogen diffusion in the Nb-1.0wt%Zr measured by mechanical spectroscopy

The scientific and technological development in the area of new materials contributed to several applications of niobium and its alloys in nuclear power plants as well as in aerospace, aeronautics, automobile and naval industries. This paper presents the interstitial diffusion coefficients of nitrogen in solid solution in the Nb-1.0wt%Zr alloy using internal friction measurements obtained by mechanical spectroscopy, which uses a torsion pendulum operating at an oscillation frequency between 1.0 Hz and 10.0 Hz. The temperature range varies from 300K to 700K, at a heating rate of 1 K/min and vacuum better than 2 x 10(-6) Torr. The results showed an increase of the interstitial diffusion coefficient of nitrogen that was correlated with configurational considerations for the octahedral interstitials.

Oxygen diffusion in Ti-10Mo alloys measured by mechanical spectroscopy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anelastic Relaxation Measurements in Nb-46wt%Ti Alloys with Interstitial Solutes in Solid Solution

Anelastic relaxation measurements were performed in a Nb-46wt%Ti alloy, in the temperature range of 300 to 700 K, using a torsion pendulum operating at an oscillating frequency near 2.0 Hz. The samples were measured in different conditions: cold worked, annealed in ultra-high vacuum and doped with several quantities of nitrogen. The relaxation spectra obtained were resolved into their component peaks, corresponding to the different kinds of interaction of the interstitial solutes with the metallic matrix. The relaxation parameters of each process were calculated using Debye's elementary peaks.

Assessment of cumulative damage by using ultrasonic C-scan on carbon fiber/epoxy composites under thermal cycling

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure and microstructure of PbTiO3 thin films obtained from hybrid chemical method

PbTiO3 thin films were deposited on Si(100) via hybrid chemical method and crystallized between 400 and 700 degreesC to study the effect of the crystallization kinetics on structure and microstructure of these materials. X-ray diffraction (XRD) technique was used to study the structure of the crystallized films. In the temperature range investigated, the lattice strain (c/a) presented a maximum value (c/a = 1.056) for film crystallized at 600 degreesC for I h. Atomic force microscopy (AFM) was used in investigation of the microstructure of the films. The rms roughness of the films linearly increases with temperature and ranged from 1.25 to 9.04 nm while the grain sizes ranged from 130.6 to 213.6 nm. Greater grain size was observed for film crystallized at 600 degreesC for 1 h. (C) 2002 Elsevier B.V. S.A. All rights reserved.

Effect of polyol excess on the electrical property of vegetable-polyurethane film

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo cinético da degradação térmica e catalítica de petróleo pesado usando Al-MCM-41

The mesoporous nanostructured materials have been studied for application in the oil industry, in particular Al-MCM-41, due to the surface area around 800 to 1.000 m2 g-1 and, pore diameters ranging from 2 to 10 nm, suitable for catalysis to large molecules such as heavy oil. The MCM-41 has been synthesized by hydrothermal method, on which aluminum was added, in the ratio Si/Al equal to 50, to increase the generation of active acid sites in the nanotubes. The catalyst was characterized by X-ray diffraction (XRD), surface area by the BET method and, the average pore volume BJH method using the N2 adsorption, absorption spectroscopy in the infrared Fourier Transform (FT-IR) and determination of surface acidity with application of a probe molecule - n-butylamine. The catalyst showed well-defined structural properties and consistent with the literature. The overall objective was to test the Al-MCM-41 as catalyst and thermogravimetric perform tests, using two samples of heavy oil with API º equal to 14.0 and 18.5. Assays were performed using a temperature range of 30-900 ° C and heating ratios (β) ranging from 5, 10 and 20 °C min-1.The aim was to verify the thermogravimetric profiles of these oils when subjected to the action of the catalyst Al- MCM-41. Therefore, the percentage ranged catalyst applied 1, 3, 5, 10 and 20 wt%, and from the TG data were applied two different kinetic models: Ozawa-Flynn-Wall (OFW) and Kissinger-Akahrira-Sunose (KAS).The apparent activation energies found for both models had similar values and were lower for the second event of mass loss known as cracking zone, indicating a more effective performance of Al-MCM-41 in that area. Furthermore, there was a more pronounced reduction in the value of activation energy for between 10 and 20% by weight of the oil-catalyst mixture. It was concluded that the Al-MCM-41 catalyst has applicability in heavy oils to reduce the apparent activation energy of a catalyst-oil system, and the best result with 20% by weight of Al-MCM-41

V2O5/TiO2 catalyst xerogels: Method of preparation and characterization

This work describes a modified sol-gel method for the preparation of V2O5/TiO2 catalysts. The samples have been characterized by N-2 adsorption at 77 K, X-ray Diffractometry (XRD), Scanning Electronic Microscopy (SEM/EDX) and Fourier Transform Infrared Spectroscopy (FT-IR). The surface area increases with the vanadia loading from 24 m(2) g(-1) for pure TiO2 to 87 m(2) g(-1) for 9 wt% of V2O5. The rutile form is predominant for pure TiO2 but becomes enriched with anatase phase when vanadia loading is increased. No crystalline V2O5 phase was observed in the diffractograms of the catalysts. Analysis by SEM showed heterogeneous granulation of particles with high vanadium dispersion. Two species of surface vanadium were observed by FT-IR spectroscopy: a monomeric vanadyl and polymeric vanadates. The vanadyl/vanadate ratio remains practically constant. Ethanol oxidation was used as a catalytic test in a temperature range from 350 to 560 K. The catalytic activity starts around 380 K. For the sample with 9 wt% of vanadia, the conversion of ethanol into acetaldehyde as the main product was approximately 90% at 473 K.

Aspirin increases tolerance to high temperature in seeds of Raphanus sativus L. cvar Early Scarlet Globe

The incubation of seeds of Raphanus sativus L. cvar Early Scarlet Globe with 10 mu M aspirin resulted in increase in the temperature range for germination. The analysis of percentage germination and germination rates indicated the increase in the optimum temperature from 21.4 to 26 degrees C although at 32.6 degrees C 80.8% of seeds germinated with aspirin and no germination in the control. The analysis of the kinetics of seed germination indicated that aspirin treatment resulted in germination by decreasing the enthalpy of activation of the process. The aspirin treatment also resulted in the synchronization of seed germination. on the base of our results we propose aspirin application in practice to increase the tolerance to high temperature and to synchronize seed germination at least in Raphanus sativus L. cvar early scarlet globe.

Effects of temperature on lung and blood gases in the South American rattlesnake Crotalus durissus terrificus

The effects of temperature on lung and blood gases were measured in the South American rattlesnake (Crotalus durissus terrificus). Arterial blood and lung gas samples were obtained from chronically cannulated animals at 15, 25, and 35 degrees C. As expected for reptiles, arterial pH fell with increased temperature (0.018 U degrees C-1 between 15 and 25 degrees C and 0.011 U degrees C-1 between 25 and 35 degrees C) while lung gas PCO2 rose from 5.8 mmHg at 15 degrees C to 13.2 mmHg at 35 degrees C. Concurrently, lung gas PO2 declined from 132 mmHg at 15 degrees C to 120 mmHg at 35 degrees C, and arterial PO2 increased from 33 to 76 mmHg in that temperature range. Arterial haemoglobin O-2 saturation rose from 0.53 at 15 degrees C to 0.83 at 25 degrees C but became slightly reduced (0.77) with a further elevation of temperature to 35 degrees C. Arterial haemoglobin concentration increased from 1.96 to 2.53 mM between 15 and 35 degrees C, consistent with higher demands on oxygen delivery to tissues at elevated temperatures. Moreover, the substantial increase of haemoglobin O-2 saturation between 15 and 25 degrees C conforms to the idea that reduction of the central vascular right-to-left shunt (pulmonary bypass of systemic venous return) is associated with high metabolic demands. (C) 1998 Elsevier B.V. All rights reserved.