The tractability of petroleum is intimately related to the type of emulsion that is formed during its production. The characteristics of water/oil and oil/water emulsions depend on some factors such as the density and the composition of the oil. In this work, the properties of oils coming from the Campos Basin, Brazil, were evaluated by means of water-in-oil emulsion physico-chemical, interfacial, and characterization tests. Such properties have been correlated with the tractability of the petroleum in order to establish a behavior prediction method based on the properties of such petroleum. The main tool used in this work was the chemiometry technique. Through this method, it was possible to conclude that density, viscosity, surface tension, and nickel content were the properties that influenced the separation of the oils. Density, pour point, initial temperature of crystal formation (TIAC), characterization factor, and nitrogen content were the properties that influenced the diameter of the emulsion drops. 相似文献
Multimedia Tools and Applications - Glaucoma is the second major cause of vision loss worldwide. It is usually caused by the increase in the intraocular pressure, which damages the optic nerve... 相似文献
During the multi-objective optimization process, numerous efficient solutions may be generated to form the Pareto frontier. Due to the complexity of formulating and solving mathematical problems, choosing the best point to be implemented becomes a non-trivial task. Thus, this paper introduces a weighting strategy named robust optimal point selection, based on ratio diversification/error, to choose the most preferred Pareto optimal point in multi-objective optimization problems using response surface methodology. Furthermore, this paper proposes to explore a theoretical gap—the prediction variance behavior related to the weighting. The ratios Shannon’s entropy/error and diversity/error and the unscaled prediction variance are experimentally modeled using mixture design and the optimal weights for the multi-objective optimization process are defined by the maximization of the proposed measures. The study could demonstrate that the weights used in the multi-objective optimization process influence the prediction variance. Furthermore, the use of diversification measures, such as entropy and diversity, associated with measures of error, such as mean absolute percent error, was determined to be useful in mapping regions of minimum variance within the Pareto optimal responses obtained in the optimization process.
Titanium is used due its excellent properties in medical and dentistry areas. With the objective of exploiting better mechanical
properties, not altering its biocompatibility, it was intended to add niobium and zirconium to the titanium, being formulated
two alloys Ti–35%Nb–5%Zr (alloy 1) and Ti–35%Nb–10%Zr (alloy 2) wt% produced by an arc melting method. The chemical analysis
of the samples was accomplished by X-ray fluorescence, and the microstrutural evaluation by scanning electron microscopy and
X-ray diffraction. The mechanical tests were: Vickers hardness, tensile strength, mechanical cycling, and fracture analysis.
The results allowed characterizing the alloy 1 as α + β type and the alloy 2 as β type. It is found that the alloy 1 presented
larger hardness and smaller tensile strength than the alloy 2. The fractures, after the tensile test, were of the ductile
type and, after the mechanical cycling, they were of the mixed type for both alloys. 相似文献
Clean Technologies and Environmental Policy - This study aims to identify explanatory factors to increase the agricultural performance of Brazilian and Australian sugarcane mills. The relevance of... 相似文献
Effective heat transfer coefficients were measured using an aluminum test body and compared with the results obtained from a Gnielinski correlation for air-blast freezing of a fruit pulp model in multilayer boxes, with the internal airflow through rectangular ducts and the hydraulic diameter as characteristic dimensions. The quantities of products inside the boxes were varied, and the inlet air velocities and temperature profiles during freezing were measured. The inlet air velocities were applied in dimensionless Gnielinski correlations to estimate the local heat transfer coefficient values. The experimental and predicted heat transfer coefficient values were used to determine an average convective heat transfer coefficient weighted by the heat transfer area. The results from this methodology were used in an analytically derived procedure for freezing-time estimates and then compared with experimental results. The average effective heat transfer coefficient underestimated freezing times and demonstrated a higher level of accuracy than the Gnielinski correlation when applied to boxes containing smaller product amounts. For experiments with greater quantity of products, the use of average heat transfer coefficients from the Gnielinski correlation yielded errors lower than 20%. Based on boundary layer theory, the Gnielinski correlation can be used to explain the isotherm behaviors observed during freezing. Many of the results satisfy the standards of accuracy used in engineering, and the procedure does not require extra computational effort. 相似文献
High heat input welding is one of the alternatives adopted by the world’s major shipyards for increasing productivity in operations for joining materials in shipbuilding. However, the thermal cycles generated during welding may cause microstructural transformations that are detrimental to the mechanical properties, mainly toughness in the heat-affected zone (HAZ). The main aim of this study was characterization of the microstructure and assessment of the mechanical properties of the HAZ of EH36 shipbuilding steel produced by controlled rolling followed by accelerated cooling (Thermo Mechanical Control Process (TMCP) – thermo-mechanically controlled process) compared to a steel of the same grade produced by conventional rolling, both welded by the submerged arc process with two levels of heat input: 76 and 130 kJ/cm. It was observed that the presence of a more refined microstructure in the different regions of the HAZ, associated with the smaller grain size of the base metal and the lower carbon equivalent, were the main factors contributing to the excellent toughness of the HAZ of TMCP steel compared to conventional steel. The results achieved show that it is possible to obtain welded joints with excellent mechanical properties and toughness when using TMCP steel for high heat input welding, and its use is a possible strategy for optimizing fabrication times and costs in the shipbuilding industry. 相似文献
This work fully demonstrated the formation of amino acids complexes with β-cyclodextrin (β-CD) by the method of nuclear magnetic resonance with the rotating frame Overhauser effect spectroscopy (ROESY) and diffusion ordered spectroscopy (DOSY) techniques. The tested amino acids display the following decreasing order of affinity for β-CD: tryptophane > tyrosine > phenylalanine > proline > histidine > isoleucine. The influence of complexation on taste perception was determined with a trained panel to qualify taste alterations of single amino acids and quantify the debittering of soy protein hydrolysate by β-CD complexation. The results showed that β-CD complexation is effective for modifying single amino acids taste perception and debittering soy protein hydrolysate. Bitterness sensation of the latter is reduced by 90% when 5% β-CD was added, thus β-CD is recommended as a prospective additive for masking bitter taste of new functional food products. 相似文献