Bio-óleo e biogás da degradação termoquímica de lodo de esgoto doméstico em cilindro rotativo

The objective of this study was to produce biofuels (bio-oil and gas) from the thermal treatment of sewage sludge in rotating cylinder, aiming industrial applications. The biomass was characterized by immediate and instrumental analysis (elemental analysis, scanning electron microscopy - SEM, X-ray diffraction, infrared spectroscopy and ICP-OES). A kinetic study on non-stationary regime was done to calculate the activation energy by Thermal Gravimetric Analysis evaluating thermochemical and thermocatalytic process of sludge, the latter being in the presence of USY zeolite. As expected, the activation energy evaluated by the mathematical model "Model-free kinetics" applying techniques isoconversionais was lowest for the catalytic tests (57.9 to 108.9 kJ/mol in the range of biomass conversion of 40 to 80%). The pyrolytic plant at a laboratory scale reactor consists of a rotating cylinder whose length is 100 cm with capable of processing up to 1 kg biomass/h. In the process of pyrolysis thermochemical were studied following parameters: temperature of reaction (500 to 600 ° C), flow rate of carrier gas (50 to 200 mL/min), frequency of rotation of centrifugation for condensation of bio-oil (20 to 30 Hz) and flow of biomass (4 and 22 g/min). Products obtained during the process (pyrolytic liquid, coal and gas) were characterized by classical and instrumental analytical techniques. The maximum yield of liquid pyrolytic was approximately 10.5% obtained in the conditions of temperature of 500 °C, centrifugation speed of 20 Hz, an inert gas flow of 200 mL/min and feeding of biomass 22 g/min. The highest yield obtained for the gas phase was 23.3% for the temperature of 600 °C, flow rate of 200 mL/min inert, frequency of rotation of the column of vapor condensation 30 Hz and flow of biomass of 22 g/min. The non-oxygenated aliphatic hydrocarbons were found in greater proportion in the bio-oil (55%) followed by aliphatic oxygenated (27%). The bio-oil had the following characteristics: pH 6.81, density between 1.05 and 1.09 g/mL, viscosity between 2.5 and 3.1 cSt and highest heating value between 16.91 and 17.85 MJ/ kg. The main components in the gas phase were: H2, CO, CO2 and CH4. Hydrogen was the main constituent of the gas mixture, with a yield of about 46.2% for a temperature of 600 ° C. Among the hydrocarbons formed, methane was found in higher yield (16.6%) for the temperature 520 oC. The solid phase obtained showed a high ash content (70%) due to the abundant presence of metals in coal, in particular iron, which was also present in bio-oil with a rate of 0.068% in the test performed at a temperature of 500 oC.

Incorporação de resíduo de perfuração em matriz cerâmica: estabilização por solidificação

One of the waste generated during the drilling of oil wells are gravel which are impregnated of drilling fluid. This residue consists of highly toxic chemicals, including toxic metals. This study suggests an alternative process to the treatment of this waste, by incorporating it the form of raw material in the ceramic matrix , and by solidification and stabilize the metals present, Aluminum (Al), Iron (Fe), Manganese (Mn) and Zinc (Zn). The raw materials were characterized by the techniques of X ray fluorescence (FRX), X ray diffraction (DRX), laser granulometry (GL), thermogravimetry (TG) and differential thermal analysis (ADT). To evaluate the percentage of gravel effect the environmental and technological properties were obtained from formulations containing 0, 10 and 20 % by weight of gravel in the ceramic matrix. After sintering at temperatures 1080, 1120 and 1160 °C, the samples were tested for water absorption, the linear shrinkage firing, voltage of rupture and solubility. The results obtained showed that the stabilization by solidification, is a viable alternative to safe disposal of waste drilling. Ceramics products can be used in the manufacture of solid bricks

Síntese e caracterização de tensoativos e estudo de equilíbrio de fase dos sistemas CnH2n+2/H2O/CnH2n+1COONa/But-OH

The growing utilization of surfactants in several different areas of industry has led to an increase on the studies involving solutions containing this type of molecules. Due to its amphiphilic nature, its molecule presents one polar part and one nonpolar end, which easily interacts with other molecules, being able to modify the media properties. When the concentration in which its monomers are saturated, the airliquid system interface is reached, causing a decrease in interfacial tension. The surfactants from pure fatty acids containing C8, C12 and C16 carbonic chains were synthesized in an alcoholic media using sodium hydroxide. They were characterized via thermal analysis (DTA and DTG) and via infrared spectroscopy, with the intention of observing their purity. Physical and chemical properties such as superficial tension, critical micelle concentration (c.m.c), surfactant excess on surface and Gibbs free energy of micellization were determined in order to understand the behaviour of these molecules with an aqueous media. Pseudo-ternary phase diagrams were obtained aiming to limit the Windsor equilibria conditions so it could be possible to understand how the surfactants carbonic chain size contributes to the microemulsion region. Solutions with known concentrations were prepared to study how the surfactants can influence the dynamic light scattering spectroscopy (DLS) and how the diffusion coefficient is influenced when the media concentration is altered. The results showed the variation on the chain size of the studied surfactant lipophilic part allows the conception of surfactants with similar interfacial properties, but dependent on the size of the lipophilic part of the surfactant. This variation causes the surfactant to have less tendency of microemulsionate oil in water. Another observed result is that the n-alcanes molecule size promoted a decrease on the microemulsion region on the obtained phase diagrams

Concepção de um secador rotatório para secagem do cefalotórax do camarão

The present work has as objective the knowledge of the process of drying of the cephalothorax of shrimp to give support the industry to make possible the use of this byproduct. In this sense, the process conditions in this tray dryer and spouted bed were analyzed. With these results, it was projected and constructs a dryer with specific characteristics for the drying of the cephalothorax. The desorption isotherms were obtained by the dynamic method in the temperatures of 20, 35 and 50º C and in the interval of 10-90% of relative humidity. It was observed that the product in form of powder can be conserved with larger stability for lower relative humidity to 40%. The curves of drying of the dryer of fixed bed were adjusted for the models: single exponential, biparametric exponential and Page. The model biparametric exponential more adequately described all the drying conditions studied. The tests carry out in spouted bed showed high drying rate for the material in the paste form in beds active dynamicly-fluid, provely the necessity of a feeding in shorter intervals of time to increase the thermal efficiency of the process. The projected dryer, be considered the obtained results, it was a rotary dryer with inert bed, feed co-current, discharge in cyclone to take place the separation gas-solid, and feed carry out in intervals of 2 minutes. The optimization of the equipment projected it was accomplished used the complete factorial experimental design 24, this had as independent variables temperature velocity of the air, feed flow rate and encapsulated concentration (albumin), as variables answers the thermal efficiency, the moisture content of obtained powder, total time of test and the efficiency of production of powder in several points of processing. The results showed that the rotary dryer with inert bed can present, also, good results if applied industrially

Eutrofização do Reservatório Cruzeta na bacia representativa do rio Seridó RN

Eutrophication has been listed as one of the main problems of water pollution on a global level. In the Brazilian semi-arid areas this problem takes even greater proportions due to characteristical water scarcity of the region. It is extremely important to the predictive eutrophication models development and to the reservoirs management in the semi-arid region, studies that promotes understanding of the mechanisms responsible for the expansion and control of algae blooms, essential for improving the water quality of these environments. The present study had as its main aims, evaluate the temporal pattern of trophic state, considering the influence of nutrients (N and P) and the light availability in the water column in the development of phytoplankton biomass, and perform the mathematical modelling of changes in phosphorus and chlorophyll a concentrations in the Cruzeta man-made lake located on Seridó, a typical semi-arid region of Rio Grande do Norte. To this, a fortnightly monitoring was performed in the reservoir in 05 stations over the months of March 2007 to May 2008. Were measured the concentrations of total phosphorus, total organic nitrogen, chlorophyll a, total, fixed and volatile suspended solids, as well as the measure of transparency (Secchi) and the profiles of photosynthetic active radiation (PAR), temperature, pH, dissolved oxygen and electrical conductivity in the water column. Measurements of vertical profiles have shown some periods of chemical and thermal stratification, especially in the rainy season, due to increased water column depth, however, the reservoir can be classified as warm polimitic. During the study period the reservoir was characterized as eutrophic considering the concentrations of phosphorus and most of the time as mesotrophic, based on the concentrations of chlorophyll a, according to the Thornton & Rast (1993) classification. The N:P relations suggest N limitation, conversely, significant linear relationship between the algae biomass and nutrients (N and P) were not observed in our study. However, a relevant event was the negative and significant correlation presented by Kt and chlorophyll a (r ² = 0.83) at the end of the drought of 2007 and the rainy season of 2008, and the algal biomass collapse observed at the end of the drought season (Dec/07). The equation used to simulate the change in the total phosphorus was not satisfactory, being necessary inclusion of parameters able to increase the power of the model prediction. The chlorophyll a simulation presented a good adjustment trend, however there is a need to check the calibrated model parameters and subsequent equation validation

Incorporação do lodo de tanque séptico como matéria-prima de uma mistura asfáltica

In Natal/RN, 68% of the population uses some kind of individual system for their domestic sewers treatment, being that the most used it is septic tank, followed by sumidouro. Every treatment system of sewers, usually used, generates a by-product denominated sludge. That residue presents some components, in its constitution, undesirable under the environmental and sanitary point of view. In such case, to assure that the system treatment has satisfactory results, it is necessary to do the adjusted disposition of the sludge sewage. Several countries are looking for technical alternatives for the use and disposition of residues. Under technical and environmental conditions appropriate, these materials can be used, decreasing the consumption of the natural resources and the treatment need, storage or elimination of the wastes, what decrease the risks created. Some of the alternatives of recycling of the sludge sewage are: the application in the agriculture, in the production of energy and as raw material in the civil construction. This study evaluated asphalt mixtures behavior that partially substituted conventional aggregates by septic tank sludge. The septic tank sludge gave origin to two raw materials called raw sludge and sludge ash. The raw sludge was put as a small aggregate and the sludge ash as filler. In the first experiment it was made a comparison between the mixture with conventional aggregates and the mixtures that replaced sand by raw sludge in the proportions from 5% to 40%. In the second experiment, it was made comparison between mixtures with 1%, 2% and 3% of sludge ash and cement. The stages developed along the study were: physical characterization of the conventional materials; physical, chemistry, thermal, mineralogical characterizations and analysis of environmental risk of the raw sludge; physical characterization and analysis of environmental risk of the sludge ash; analysis of the mixtures performance through its volumetric and mechanical characteristics; forecast of the mixtures susceptibility in the moisture presence. For the grain size composition used and with the percentage asphalt adopted, the mixtures with up to 7,5% of raw sludge in his composition attend to the National Department of Transports Infrastructure (DNIT) specifications. However, in agreement with the mixtures susceptibility in the moisture presence, the mixtures with addition of raw sludge don't present satisfactory acting. In such case, they could be used in arid and semi-arid areas. The raw sludge application in mixtures increased their voids volume and their stability. However, it damaged mixtures adhesiveness. Mixtures with sludge ash and with cement presented similar behavior. However, mixtures with sludge ash presented a better performance than mixtures with cement as for their stability and their tensile strength ratio. The mixture with 1% of sludge ash is better. The wastes studied don't represent environmental risk

Física no cotidiano: da cozinha para a sala de aula relato de uma experiência didática no município de Limoeiro do Norte (CE)

Brazilian high school teaching has passing through important changes. Based on current legislation and other official documents this research focus on the notion of contextualization, discussing the possibilities of a Physics teaching contextualized at a kitchen environment. Given the difficulties presented by students in establishing the relation between the contents discussed in classroom and their own daily lives, we propose the elaboration and application of a didactic unity. This started after the analyses of an initial questionnaire answered by the students. The didactic unity was elaborated based on an earlier proposal made by GREF (Physics Teaching Reelaboration Group) for a Thermal Physics course, and involved situations on students daily lives, in particular, those activities tried to relate formal contents discussed in classrooms to the kitchen environment. The didactic unity was applied to a public high school classroom at Limoeiro do Norte (CE). After evaluation of this experience it is possible to state that contextualization is a challenge that shall be faced, so that students may have a more critical look at physics, understanding that this subject is of relevance to all of us and is present in all world around us

Estudo da influência de tratamentos químicos da fibra de sisal nas propriedades de compósitos com borracha nitrílica

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

Avaliação de clones de borracha natural crua por ensaios padrão e análise dinâmico-mecânica

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

Conforto térmico em espaços públicos de passagem: estudos em ruas de pedestres no estado de São Paulo

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

Some Biochemical properties of polyphenoloxidase from spearmint (Mentha arvensis)

Polifenoloxidase (PPO, EC 1.14.18.1) extraída de folhas de Mentha arvensis foi isolada por precipitação com (NH4)2SO4 e diálise extensiva. Seu pH e temperatura ótimos variaram com o substrato. A PPO apresentou atividade com vários difenóis. Valores de Km foram 0,825; 0,928 e 7,41 mM para ácido caféico, 4-metilcatecol e catecol, respectivamente. Na inativação térmica, 50% da enzima foi inativada após 60 e 15 segundos a 70 e 75ºC, respectivamente. A medida de atividade residual mostrou um efeito estabilizante de sacarose a várias temperaturas e uma energia de ativação (Ea) para inativação aumentando com a concentração de sacarose de 0 a 40% (p/p). Valores de energias de ativação de 78,13; 80,37; 82,79 and 81,00 kJ/Mol foram encontradas para 0, 15, 30 e 40% de sacarose, respectivamente. A PPO foi inibida pelos ácidos ascórbico, benzóico, cinamico, ferulico, p-cumárico, protocatéquico, além de metabisulfito de sódio, resorcinol e pirogalol. Os valores de Ki mostram que o ácido ascórbico foi o mais efetivo inibidor. O tipo de inibição foi determinado para cada inibidor.

Propriedades Físicas do Semicondutor Bi2Te3

Thermoelectric Refrigerators (TEC Thermoelectric Cooling) are solid-state heat pumps used in applications where stabilization of temperature cycles or cooling below the room temperature are required. TEC are based on thermoelectric devices, and these in turn, are based on the Peltier effect, which is the production of a difference in temperature when an electric current is applied to a junction formed by two non-similar materials. This is one of the three thermoelectric effects and is a typical semiconductor junction phenomenon. The thermoelectric efficiency, known as Z thermoelectric or merit figure is a parameter that measures the quality of a thermoelectric device. It depends directly on electrical conductivity and inversely on the thermal conductivity. Therefore, good thermoelectric devices have typically high values of electrical conductivity and low values of thermal conductivity. One of the most common materials in the composition of thermoelectric devices is the semiconductor bismuth telluride (Bi2Te3) and its alloys. Peltier plates made up by crystals of semiconductor P-type and N-type are commercially available for various applications in thermoelectric systems. In this work, we characterize the electrical properties of bismuth telluride through conductivity/resistivity of the material, and X-rays power diffraction and magnetoresistance measurements. The results were compared with values taken from specific literature. Moreover, two techniques of material preparation, and applications in refrigerators, are discussed

Deposição de A/N por sputtering não reativo

In this work we deposit via non-reactive magnetron sputtering of radio-frequency nanofilmes of nitreto of aluminum(AlN). The nanofilms aluminum nitride are semiconductors materials with high thermal conductivity, high melting point, piezoelectricity and wide band gap (6, 2 eV) with hexagonal wurtzite crystal structure, belonging to the group of new materials called III-V nitrides in which together with the gallium nitride and indium nitride have attracted much interest because they have physical and chemical properties relevant to new technological applications, mainly in microelectronic and optoelectronic devices. Three groups were deposited with thicknesses nanofilms time dependent on two substrates (glass and silicon) at a temperature of 25 ° C. The nanofilms AlN were characterized using three techniques, X-ray diffraction, Raman spectroscopy and atomic force microscopy (AFM), examined the morphology of these. Through the analysis of X-rays get the thickness of each sample with its corresponding deposition rate. The analysis of X-rays also revealed that nanofilms are not crystalline, showing the amorphous character of the samples. The results obtained by the technique, atomic force microscopy (AFM) agree with those obtained using the technique of X-rays. Characterization by Raman spectroscopy revealed the existence of active modes characteristic of AlN in the samples

Fases magnéticas de sistemas nanoestruturados de terras-raras

There is presently a worldwide interest in artificial magnetic systems which guide research activities in universities and companies. Thin films and multilayers have a central role, revealing new magnetic phases which often lead to breakthroughs and new technology standards, never thought otherwise. Surface and confinement effects cause large impact in the magnetic phases of magnetic materials with bulk spatially periodic patterns. New magnetic phases are expected to form in thin film thicknesses comparable to the length of the intrinsic bulk magnetic unit cell. Helimagnetic materials are prototypes in this respect, since the bulk magnetic phases consist in periodic patterns with the length of the helical pitch. In this thesis we study the magnetic phases of thin rare-earth films, with surfaces oriented along the (002) direction. The thesis includes the investigation of the magnetic phases of thin Dy and Ho films, as well as the thermal hysteresis cycles of Dy thin films. The investigation of the thermal hysteresis cycles of thin Dy films has been done in collaboration with the Laboratory of Magnetic Materials of the University of Texas, at Arlington. The theoretical modeling is based on a self-consistent theory developed by the Group of Magnetism of UFRN. Contributions from the first and second neighbors exchange energy, from the anisotropy energy and the Zeeman energy are calculated in a set of nonequivalent magnetic ions, and the equilibrium magnetic phases, from the Curie temperature up to the Nèel temperature, are determined in a self-consistent manner, resulting in a vanishing torque in the magnetic ions at all planes across the thin film. Our results reproduce the known isothermal and iso-field curves of bulk Dy and Ho, and the known spin-slip phases of Ho, and indicate that: (i) the confinement in thin films leads to a new magnetic phase, with alternate helicity, which leads to the measured thermal hysteresis of Dy ultrathin films, with thicknesses ranging from 4 nm to 16 nm; (ii) thin Dy films have anisotropy dominated surface lock-in phases, with alignment of surface spins along the anisotropy easy axis directions, similar to the known spin-slip phases of Ho ( which form in the bulk and are commensurate to the crystal lattice); and (iii) the confinement in thin films change considerably the spin-slip patterns of Ho.

Aplicações da q-Álgebra em física da matéria condensada

We address the generalization of thermodynamic quantity q-deformed by q-algebra that describes a general algebra for bosons and fermions . The motivation for our study stems from an interest to strengthen our initial ideas, and a possible experimental application. On our journey, we met a generalization of the recently proposed formalism of the q-calculus, which is the application of a generalized sequence described by two parameters deformation positive real independent and q1 and q2, known for Fibonacci oscillators . We apply the wellknown problem of Landau diamagnetism immersed in a space D-dimensional, which still generates good discussions by its nature, and dependence with the number of dimensions D, enables us future extend its application to systems extra-dimensional, such as Modern Cosmology, Particle Physics and String Theory. We compare our results with some experimentally obtained performing major equity. We also use the formalism of the oscillators to Einstein and Debye solid, strengthening the interpretation of the q-deformation acting as a factor of disturbance or impurity in a given system, modifying the properties of the same. Our results show that the insertion of two parameters of disorder, allowed a wider range of adjustment , i.e., enabling change only the desired property, e.g., the thermal conductivity of a same element without the waste essence