Wettability of Aqueous Rhamnolipids Solutions Produced by Pseudomonas aeruginosa LBI

The wetting behavior of rhamnolipids produced by Pseudomonas aeruginosa LBI strain grown on waste oil substrate and sodium dodecyl sulfate (SDS) on glass, polyethylene terephthalate (PET), poly(vinyl chloride) (PVC), poly(epsilon-caprolactone) (PCL) and polymer blend (PVC-PCL) was investigated by the measuring contact angle of sessile drops, to determine the wetting characteristics of rhamnolipids. The comparison of the wetting profiles showed that at low SDS and rhamnolipid concentrations, the contact angle increased and when the concentration of the surfactant increased further, the contact angle decreased. The blend surface (PVC-PCL) showed better wettability than the homopolymers themselves and the blend changed the surface hydrophobicity of the polymer, making it more hydrophilic. The rhamnolipids produced by the LBI strain exhibited superior wetting abilities than the chemical surfactant SDS one. This is the first work that evaluates the wetting properties of rhamnolipids on polymer blends.

Análise tribológica de um sistema de acionamento alternativo de pigs para a indústria do petróleo

It is analyzed through the concepts of tribology and mechanical contact and damage the suggestion of implementing a backup system for traction and passage of Pipeline Inspection Gauge (Pig) from the inside of pipelines. In order to verify the integrity of the pipelines, it is suggested the possibility of displacement of such equipment by pulling wires with steel wires. The physical and mechanical characteristics of this method were verified by accelerated tests in the laboratory in a tribological pair, wire versus a curve 90. It also considered the main mechanisms of wear of a sliding system with and without lubricant, in the absence and presence of contaminants. To try this, It was constructed a test bench able to reproduce a slip system, work on mode back-and-forth ("reciprocation"). It was used two kinds of wires, a galvanized steel and other stainless steel and the results achieved using the two kinds of steel cables were compared. For result comparative means, it was used steel cables with and without coating of Poly Vinyl Chloride (PVC). The wires and the curves of the products were characterized using metallographic analysis, microhardness Vickers tests, X-ray diffraction (XRD), X-Ray Refraction (XRF) and tensile tests. After the experiments were analyzed some parameters that have been measurable, it demonstrates to the impracticality of this proposed method, since the friction force and the concept of alternating request at the contact between the strands of wire and the inner curves that are part ducts caused severe wear. These types of wear are likely to cause possible failures in future products and cause fluid leaks

Matrizes poliméricas puras e modificadas para adsorção do gás sulfeto de hidrogênio

The underground natural gas found associated or not with oil is characterized by a mixture of hydrocarbons and residual components such as carbon dioxide (CO2), nitrogen gas (N2) and hydrogen sulfide (H2S), called contaminants. The H2S especially promotes itself as a contaminant of natural gas to be associated with corrosion of pipelines, to human toxicity and final applications of Natural Gas (NG). The sulfur present in the GN must be fully or partially removed in order to meet the market specifications, security, transport or further processing. There are distinct and varied methods of desulfurization of natural gas processing units used in Natural Gas (UPGN). In order to solve these problems have for example the caustic washing, absorption, the use of membranes and adsorption processes is costly and great expenditure of energy. Arises on such findings, the need for research to active processes of economic feasibility and efficiency. This work promoted the study of the adsorption of sulfide gas in polymer matrices hydrogen pure and modified. The substrates of Poly(vinyl chloride) (PVC), poly(methyl methacrylate) (PMMA) and sodium alginate (NaALG) were coated with vanadyl phosphate compounds (VOPO4.2H2O), vanadium pentoxide (V2O5), rhodamine B (C28H31N2O3Cl) and ions Co2+ and Cu2+, aiming to the adsorption of hydrogen sulfide gas (H2S). The adsorption tests were through a continuous flow of H2S in a column system (fixed bed reactor) adsorption on a laboratory scale. The techniques used to characterize the adsorbents were Infrared spectroscopy (FTIR), thermogravimetry analysis (TGA), X-ray fluorescence (XRF), the X-ray diffraction (XRD) electron microscopy (SEM). Such work indicates, the results obtained, the adsorbents modified PMMA, PVC and NaALG have a significant adsorptive capacity. The matrix that stood out and had the best adsorption capacity, was to ALG modified Co2+ with a score of 12.79 mg H2S / g matrix

Wettability of Aqueous Rhamnolipids Solutions Produced by Pseudomonas aeruginosa LBI

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

Biotreatment effects in films and blends of PVC/PCL previously treated with heat

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

Caracterização mecânica e térmica de compósitos de poli (cloreto de vinila) reforçados com fibras de sisal

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

Thermal degradation of geomembranes after exposure to heat

HDPE and PVC geomembranes are sensitive to changes in their properties when in contact with high temperatures. The effects of hot temperature on polymeric geomembranes are assessed by the ASTM D794 and ASTM D5721.This paper brings an analysis of degradation of the Poly Vinyl Chloride (PVC) and High Density Poly Ethylene (HDPE) geomembranes when exposed to conventional and air oven after specific periods.. Mechanical and physical properties were evaluated. OIT tests were also performanced to evaluate the level of oxidation degradation occurred on the HDPE geomembranes. Geomembranes of two thicknesses were tested: 1.0, 2.0 nun (PVC) and 0.8, 2.5 mm, (HDPE). The results obtained show, for example, that after the last period of exposure, the PVC geomembranes (1.0, 2.0 mm) were more rigid and stiffer than fresh samples. The HDPE geomembranes, on the other hand, when exposed to heat presented increases in deformation. OIT tests showed efficient to detect some level of degradation on the HDPE geomembranes.

Design of biogas pipeline - Energy and sanitation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Development and application of an electronic tongue for detection and monitoring of nitrate, nitrite and ammonium levels in waters

This work presents the first study and development of an electronic tongue analysis system for the monitoring of nitrogen stable species: nitrate, nitrite and ammonium in water. The electronic tongue was composed of an array of 15 potentiometric poly(vinyl chloride) membrane sensors sensitive to cations and anions plus an artificial neural network (ANN) response model. The building of the ANN model was performed in a medium containing sodium, potassium, and chloride as interfering ions, thus simulating real environmental samples. The correlation coefficient in the cross-validation of nitrate, nitrite and ammonium was satisfactory in the three cases with values higher than 0.92. Finally, the utility of the proposed system is shown in the monitoring of the photoelectrocatalytic treatment of nitrate. © 2013 Elsevier B.V.

Blendas de PVC/PCL foto/termo e biotratadas com fungos de solo (Phanerochaete chrysosporium e Aspergillus fumigatus)

Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC

Dispositivo microfluídico de borracha natural (LAB-ON-A-CHIP)

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

Biodegradation of films of low density polyethylene (LDPE), poly(hydroxibutyrate-co-valerate) (PHBV), and LDPE/PHBV (70/30) blend with Paecilomyces variotii

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of Particle Size, Applied Compression, and Substratum Material on Particle-Surface Adhesion Force Using the Centrifuge Technique

The centrifuge technique was used to investigate the influence of particle size, applied compression, and substrate material (stainless steel, glass, Teflon, and poly(vinyl chloride)) on particle-surface adhesion force. For this purpose, phosphatic rock (rho(p) = 3090 kg/m(3)) and manioc starch particles (rho(p) = 1480 kg/m(3)) were used as test particles. A microcentrifuge that reached a maximum rotation speed of 14 000 rpm and which contained specially designed centrifuge tubes was used in the adhesion force measurements. The curves showed that the adhesion force profile followed a normal log distribution. The adhesion force increased linearly with particle size and with the increase of each increment of compression force. The manioc starch particles presented greater adhesion forces than the phosphatic rock particles for all particle sizes studied. The glass substrate showed a higher adherence than the other materials, probably due to its smoother topographic surface roughness in relation to the other substrata.

Numerical simulation of anisotropic polymeric foams

This paper shows in detail the modelling of anisotropic polymeric foam under compression and tension loadings, including discussions on isotropic material models and the entire procedure to calibrate the parameters involved. First, specimens of poly(vinyl chloride) (PVC) foam were investigated through experimental analyses in order to understand the mechanical behavior of this anisotropic material. Then, isotropic material models available in the commercial software Abaqus (TM) were investigated in order to verify their ability to model anisotropic foams and how the parameters involved can influence the results. Due to anisotropy, it is possible to obtain different values for the same parameter in the calibration process. The obtained set of parameters are used to calibrate the model according to the application of the structure. The models investigated showed minor and major limitations to simulate the mechanical behavior of anisotropic PVC foams under compression, tension and multi-axial loadings. Results show that the calibration process and the choice of the material model applied to the polymeric foam can provide good quantitative results and save project time. Results also indicate what kind and order of error one will get if certain choices are made throughout the modelling process. Finally, even though the developed calibration procedure is applied to specific PVC foam, it still outlines a very broad drill to analyze other anisotropic cellular materials.

Study of an anisotropic polymeric cellular material under compression loading

This paper emphasizes the influence of micro mechanisms of failure of a cellular material on its phenomenological response. Most of the applications of cellular materials comprise a compression loading. Thus, the study focuses on the influence of the anisotropy in the mechanical behavior of cellular material under cyclic compression loadings. For this study, a Digital Image Correlation (DIC) technique (named Correli) was applied, as well as SEM (Scanning Electron Microscopy) images were analyzed. The experimental results are discussed in detail for a closed-cell rigid poly (vinyl chloride) (PVC) foam, showing stress-strain curves in different directions and why the material can be assumed as transversely isotropic. Besides, the present paper shows elastic and plastic Poisson's ratios measured in different planes, explaining why the plastic Poisson's ratios approach to zero. Yield fronts created by the compression loadings in different directions and the influence of spring-back phenomenon on hardening curves are commented, also.