A statistical evaluation of the effects of process variables during catalytic hydrogenation of passion fruit (passiflora edulis) seed oil

ABSTRACT: Hydrogenation of passion fruit (passiflora edulis) seed oil was carried out with a commercial nickel/silica catalyst under different experimental conditions. The influence of reaction parameters (reaction temperature, hydrogen pressure, amount of catalyst, agitation rate and reaction time) on the response variable (iodine value) was studied using a central composite rotatable design and six center points for replication. Under the experimental conditions used, the model response equations for the iodine value showed good agreement with the experimental results.

Optimization of annatto (Bixa orellana L.) drying in fixed bed

ABSTRACT: The drying of annatto seeds (Bixa orellana L.), red piave cultivate, was studied in a fixed bed dryer. The best conditions were estimated to minimize the loss of coloring and to obtain final moisture of the seeds in appropriate levels to its conservation and maintenance of quality. The quantification of the influence of entrance variables in the final contents of bixin and moisture seeds and the identification of the optimal point was performed through the techniques of factorial design, response surfaces methodology, canonical analysis and desirability function. It was verified that the final moisture of the seeds may be estimated by a second-order polynomial model and that the final content of bixin is only significantly influenced by the time of drying being described properly by a linear model, for the seeds used in this study.

On the prediction of pickup and saltation velocities in pneumatic conveying

This paper presents a comparative study of the critical pickup and saltation velocities of particles in horizontal pipelines for pneumatic conveying design. A comparative study is performed using different existing correlations in the literature for the determination of the minimum velocity of transport as a function of the particle and pipe diameter, particle density, solid mass flow rate and particle sphericity. Their limitations and difficulties in predicting those critical velocities are analyzed. For the pickup velocity, an experimental study was also carried out in order to support the analysis. Recommendations are presented on the use of such correlations.

Physical-chemical characterization of biomass samples for application iin pyrolysis process

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The "chemical oxygen demand/total volatile acids" ratio as an anaerobic treatability indicator for landfill leachates

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

Verification of applicability of the polyurethane adhesive based on castor oil in the manufacture of glued laminated bamboo

The current concern with the environment promotes the development of new technologies for production with use of alternative materials, from renewable resources, and changes in production processes, having as main objective the reduction of environmental impact. One of the alternatives for cleaner production is the use of castor oil derivatives instead of non-renewable sources, such as adhesives based on PVA (polyvinyl acetate), applied in the manufacturing process of glued laminated bamboo. Based on the versatility of the bamboo laminate and the castor oil, and from the perspective of sustainability, this study aims to contribute to the application of new materials and processes, used in the manufacturing industry, by proposing the use of the polyurethane adhesive based on castor oil for glued laminated bamboo manufacturing, which can later be used in the manufacture of several products. To verify the applicability of the polyurethane adhesive based on castor oil in the glued laminated bamboo manufacture, mechanical tests of traction and shearing of the glue sheet were performed in specimens of the said material, and the results were compared with the Cascorez 2590 and Waterbond adhesives. The results showed that the polyurethane adhesive based on castor oil, in the traction test, has superior performance than the Waterbond adhesive and slightly below than the Cascorez 2590 adhesive, but in the shear test, the polyurethane adhesive based on castor oil presented a slightly inferior performance than the other two adhesives used in the comparison.

The chemical oxygen demand / total volatile acids ratio as an anaerobic treatability indicator for landfill leachates

In some operational circumstances a fast evaluation of landfill leachate anaerobic treatability is necessary, and neither Biochemical Methane Potential nor BOD/COD ratio are fast enough. Looking for a fast indicator, this work evaluated the anaerobic treatability of landfill leachate from São Carlos-SP (Brazil) in a pilot scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR). The experiment was conducted at ambient temperature in the landfill area. After the acclimation, at a second stage of operation, the AnSBBR presented efficiency above 70%, in terms of COD removal, utilizing landfill leachate without water dilution, with an inlet COD of about 11,000 mg.L-1, a TVA/COD ratio of approximately 0.6 and reaction time equal to 7 days. To evaluate the landfill leachate biodegradability variation over time, temporal profiles of concentration were performed in the AnSBBR. The landfill leachate anaerobic biodegradability was verified to have a direct and strong relationship to the TVA/COD ratio. For a TVA/CODTotal ratio lower than 0.20, the biodegradability was considered low, for ratios between 0.20 and 0.40 it was considered medium, and above 0.40 it was considered high.

MOLECULAR DYNAMICS STUDIES OF SIMPLE MODEL FLUIDS AND WATER CONFINED IN CARBON NANOTUBE

Molecular Dynamics (MD) simulation is one of the most important computational techniques with broad applications in physics, chemistry, chemical engineering, materials design and biological science. Traditional computational chemistry refers to quantum calculations based on solving Schrodinger equations. Later developed Density Functional Theory (DFT) based on solving Kohn-Sham equations became the more popular ab initio calculation technique which could deal with ~1000 atoms by explicitly considering electron interactions. In contrast, MD simulation based on solving classical mechanics equations of motion is a totally different technique in the field of computational chemistry. Electron interactions were implicitly included in the empirical atom-based potential functions and the system size to be investigated can be extended to ~106 atoms. The thermodynamic properties of model fluids are mainly determined by macroscopic quantities, like temperature, pressure, density. The quantum effects on thermodynamic properties like melting point, surface tension are not dominant. In this work, we mainly investigated the melting point, surface tension (liquid-vapor and liquid-solid) of model fluids including Lennard-Jones model, Stockmayer model and a couple of water models (TIP4P/Ew, TIP5P/Ew) by means of MD simulation. In addition, some new structures of water confined in carbon nanotube were discovered and transport behaviors of water and ions through nano-channels were also revealed.

DESIGN AND ANALYSIS OF MULTIFUNCTIONAL ROBOT FOR NOTES

The elimination of all external incisions is an important step in reducing the invasiveness of surgical procedures. Natural Orifice Translumenal Endoscopic Surgery (NOTES) is an incision-less surgery and provides explicit benefits such as reducing patient trauma and shortening recovery time. However, technological difficulties impede the widespread utilization of the NOTES method. A novel robotic tool has been developed, which makes NOTES procedures feasible by using multiple interchangeable tool tips. The robotic tool has the capability of entering the body cavity through an orifice or a single incision using a flexible articulated positioning mechanism and once inserted is not constrained by incisions, allowing for visualization and manipulations throughout the cavity. Multiple interchangeable tool tips of the robotic device initially consist of three end effectors: a grasper, scissors, and an atraumatic Babcock clamp. The tool changer is capable of selecting and switching between the three tools depending on the surgical task using a miniature mechanism driven by micro-motors. The robotic tool is remotely controlled through a joystick and computer interface. In this thesis, the following aspects of this robotic tool will be detailed. The first-generation robot is designed as a conceptual model for implementing a novel mechanism of switching, advancing, and controlling the tool tips using two micro-motors. It is believed that this mechanism achieves a reduction in cumbersome instrument exchanges and can reduce overall procedure time and the risk of inadvertent tissue trauma during exchanges with a natural orifice approach. Also, placing actuators directly at the surgical site enables the robot to generate sufficient force to operate effectively. Mounting the multifunctional robot on the distal end of an articulating tube provides freedom from restriction on the robot kinematics and helps solve some of the difficulties otherwise faced during surgery using NOTES or related approaches. The second-generation multifunctional robot is then introduced in which the overall size is reduced and two arms provide 2 additional degrees of freedom, resulting in feasibility of insertion through the esophagus and increased dexterity. Improvements are necessary in future iterations of the multifunctional robot; however, the work presented is a proof of concept for NOTES robots capable of abdominal surgical interventions.

PHYSICO-CHEMICAL, SPECTROSCOPICAL AND THERMAL CHARACTERIZATION OF BIODIESEL OBTAINED BY ENZYMATIC ROUTE AS A TOOL TO SELECT THE MOST EFFICIENT IMMOBILIZED LIPASE

Two microbial lipases from Burkholderia cepacia and Pseudomonas fluorescens were evaluated as catalysts for the enzymatic transesterification of beef tallow with ethanol and the most efficient lipase source was selected by taking into account the properties of the product to be used as fuel. Both lipases were immobilized on an epoxy silica-polyvinyl alcohol composite by covalent immobilization and used to perform the reactions under the following operational conditions: beef tallow-to-ethanol molar ratio of 1:9, 45 degrees C and 400 units of enzymatic activity per gram of fat. Products, characterized using Fourier Transform Infrared spectroscopy (FTIR), viscosimetry, thermogravimetry and H-1 NMR spectroscopy, suggested that the biodiesel sample obtained in the reaction catalyzed by Burkholderia cepacia lipase has the best set of properties for fuel usage.

USE OF BARU OIL (Dipteryx alata Vog.) TO PRODUCE BIODIESEL AND STUDY OF THE PHYSICAL AND CHEMICAL CHARACTERISTICS OF BIODIESEL/PETROLEUM DIESEL FUEL BLENDS

We describe production of methyl and ethyl esters derived from baru oil (Dipteryx alata Vog.). Water and alcohols are removed from the biodiesel obtained by simple distillation. We study the acidity, density, iodine number, viscosity, water content, peroxide number, external appearance, and saponification number of the oil, its methyl and ethyl esters (biodiesels) and their blends (B5, B10, B15, B20, and B30) with commercial diesel fuel.

Microparticulated Hydrochlorothiazide Solid Dispersion: Enhancing Dissolution Properties via Spray Drying

The aim of the present study was to obtain microparticles of hydrochlorothiazide, a diuretic drug that practically insoluble in water, by spray drying and to investigate the influence of process parameters using a three-level, three-factor Box-Behnken design. Process yields, moisture content, particle size, flowability, and solubility were used to evaluate the spray-dried microparticles. The data were analyzed by response surface methodology using analysis of variance. The independent variables studied were outlet temperature, atomization pressure, and drug content. The formulations were prepared using polyvinylpyrrolidone and colloidal silicon dioxide as the hydrophilic carrier and drying aid, respectively. The microparticle yield ranged from 18.15 to 59.02% and resulted in adequate flow (17 to 32 degrees), moisture content between 2.52 to 6.18%, and mean particle size from 45 to 59 mu m. The analysis of variance showed that the factors studied influenced the yields, moisture content, angle of repose, and solubility. Thermal analysis and X-ray diffractometry evidenced no drug interactions or chemical modifications. Photomicrographs obtained by scanning electron microscopy showed spherical particles. The solubility and dissolution rates of hydrochlorothiazide were remarkably improved when compared with pure drug. Therefore, the results confirmed the high potential of the spray-drying technique to obtain microparticulate hydrochlorothiazide with enhanced pharmaceutical and dissolution properties.

Feasibility Study of a Solar Reactor for Phenol Treatment by the Photo-Fenton process in Aqueous Solution

Solar reactors can be attractive in photodegradation processes due to lower electrical energy demand. The performance of a solar reactor for two flow configurations, i.e., plug flow and mixed flow, is compared based on experimental results with a pilot-scale solar reactor. Aqueous solutions of phenol were used as a model for industrial wastewater containing organic contaminants. Batch experiments were carried out under clear sky, resulting in removal rates in the range of 96100?%. The dissolved organic carbon removal rate was simulated by an empirical model based on neural networks, which was adjusted to the experimental data, resulting in a correlation coefficient of 0.9856. This approach enabled to estimate effects of process variables which could not be evaluated from the experiments. Simulations with different reactor configurations indicated relevant aspects for the design of solar reactors.

Engineering Active Pharmaceutical Ingredients by Spray Drying: Effects on Physical Properties and In Vitro Dissolution

Active pharmaceutical ingredients have very strict quality requirements; minor changes in the physical and chemical properties of pharmaceuticals can adversely affect the dissolution rate and therefore the bioavailability of a given drug. Accordingly, the aim of the present study was to investigate the effect of spray drying on the physical and in vitro dissolution properties of four different active pharmaceutical ingredients, namely carbamazepine, indomethacin, piroxicam, and nifedipine. Each drug was dispersed in a solution of ethanol and water (70:30) and subjected to single-step spray drying using similar operational conditions. A complete characterization of the spray-dried drugs was performed via differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), particle size distribution analysis, solubility analysis, and an in vitro dissolution study. The results from the thermal analysis and X-ray diffraction showed that, except for carbamazepine, no chemical modifications occurred as a result of spray drying. Moreover, the particle size distribution of all the spray-dried drugs significantly decreased. In addition, SEM images showed that most of the particles had an irregular shape. There was no significant improvement in the solubility of the spray-dried drugs compared with the unprocessed compounds; however, in general, the dissolution rates of the spray-dried drugs showed a remarkable improvement over their non-spray-dried counterparts. Therefore, the results from this study demonstrate that a single spray-drying step may lead to changes in the physical properties and dissolution characteristics of drugs and thus improve their therapeutic action.

Physico-chemical, spectroscopical and thermal characterization of biodiesel obtained by enzymatic route as a tool to select the most efficient immobilized lipase

Two microbial lipases from Burkholderia cepacia and Pseudomonas fluorescens were evaluated as catalysts for the enzymatic transesterification of beef tallow with ethanol and the most efficient lipase source was selected by taking into account the properties of the product to be used as fuel. Both lipases were immobilized on an epoxy silica-polyvinyl alcohol composite by covalent immobilization and used to perform the reactions under the following operational conditions: beef tallow-to-ethanol molar ratio of 1:9, 45ºC and 400 units of enzymatic activity per gram of fat. Products, characterized using Fourier Transform Infrared spectroscopy (FTIR), viscosimetry, thermogravimetry and ¹H NMR spectroscopy, suggested that the biodiesel sample obtained in the reaction catalyzed by Burkholderia cepacia lipase has the best set of properties for fuel usage.