Precificação do biogás produzido por autoprodutores, considerando seu transporte por meio de gasodutos existentes

The expansion of the energy matrix is a matter of great importance since the recent problems facing the country in this sector, such as rationing mobilized in 2001. Moreover, there is also concern with global sustainable development. Brazil is producing about 64 million cubic meters of biogas per day, but only a small percentage of this total is harnessed as an energy resource. Compounders are considered potential, for example, landfill energy (LE) and sewage treatment plants (STP), which can be adapted to produce biogas and market them. The work focuses its studies on biogas produced by these small and medium compounders. Are proposed and studied the following alternatives for the utilization of biogas energy: generation and sale of electricity through the installation of a small power station within the landfill, and purification and marketing of gas, whose price will be a consideration on the price of natural gas, taking into account the percentage of methane present in the biogas. Trade ensures that gas plus a destination ecologically appropriate to it, taking advantage of its energy

Preparação e caracterização de vidros contendo nanopartículas de Ag

This work consists of preparation and characterization of glasses containing transition noble metals and the study of optical properties of such materials. The glasses were prepared by quenching of the glass melt followed by heat treatment and polishing of the monoliths. The structural characterization of glasses was made using differential thermal analysis, X-ray, Raman and infrared spectroscopies, while the optical properties were studied by UV-Vis and M-Lines spectroscopies. Preliminary results have shown that the color of the glasses is dependent on both concentration of silver and the melting temperature of the melt. Controlled heat treatments have been used to induce the crystallization of Ag nanoparticles within the glass. The study of crystallization was accompanied by electron microscopy and UV-Vis spectroscopy. Data from electron diffraction, as well as chemical analysis, EDX, were obtained using a transmission electron microscope. EDX data have shown that the atomic percentage of Ag is higher on the nanoparticle. X-ray diffraction was used in order to characterize the composition of the crystals and cubic AgCl was identified as the main crystallized nanophase obtained after annealing

Avaliação das doses de cães submetidos a exames radiográficos de pulmão

This study aims to determine surface skin doses in dogs (with suspected pulmonary metastasis) submitted to chest X-rays using the technique of thermoluminescence dosimetry. Twenty seven exams from different dogs were performed at the Faculdade de Medicina Veterinária e Zootecnia da Universidade Estadual Paulista (FMVZ-UNESP/Botucatu). The doses were evaluated using thermoluminescent dosimeters of calcium sulphate doped with dysprosium (CaSO4:Dy) produced by the Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN). The pulmonary metastasis exams are carried out in three projections, one dorsal-ventral and two lateral-lateral. During the procedures the projection thicknesses and source-skin surface distances were registered. To simulate the dog phantom the dosimeters were positioned in a cubic simulator (30x30x30 cm) of polymethylmethacrylate (PMMA) filled with water and irradiated according to the parameters of projections with the X-ray energies ranging from 45 to 70 kV. To estimate the surface skin dose the dose-response curves were obtained for X-ray energies of 50 and 70 kV using the diagnostic X-ray beam machine of the Instruments Calibration Laboratory of IPEN for doses of 1.5, 2.0, 2.5, 3.5 and 4.0 mGy. The main difficulty of this work was the dog immobilization that is reflected in poor-quality diagnostic imaging and, consequently, demands the repetition of the exams, which contributes to the increase of the doses received by the animals being studied and the clinical staff. The doses evaluated in this type of procedure are between 0.43 and 4.22 mGy. This research has shown to be extremely important for the assessment of doses involved in veterinary diagnostic radiology procedures, and as a parameter in the individual monitoring of pet’s owners who assist the animal positioning and occupationally exposed workers of the Department of Veterinary Radiology

Efeitos da dosagem de monensina sódica sobre o desempenho produtivo, comportamento ingestivo, saúde ruminal e características de carcaça em bovinos Nelore confinados

Pós-graduação em Ciência e Tecnologia Animal - FEIS

On symmetries of singular implicit ODEs

We study implicit ODEs, cubic in derivative, with infinitesimal symmetry at singular points. Cartan showed that even at regular points the existence of nontrivial symmetry imposes restrictions on the ODE. Namely, this algebra has the maximal possible dimension 3 iff the web of solutions is flat. For cubic ODEs with flat 3-web of solutions we establish sufficient conditions for the existence of nontrivial symmetries at singular points and show that under natural assumptions such a symmetry is semi-simple, i.e. is a scaling is some coordinates. We use this symmetry to find first integrals of the ODE.

Local classification of singular hexagonal 3-webs with holomorphic Chern connection form and infinitesimal symmetries

Implicit ODE, cubic in derivative, generically has no infinitesimal symmetries even at regular points with distinct roots. Cartan showed that at regular points, ODEs with hexagonal 3-web of solutions have symmetry algebras of the maximal possible dimension 3. At singular points such a web can lose all its symmetries. In this paper we study hexagonal 3-webs having at least one infinitesimal symmetry at singular points. In particular, we establish sufficient conditions for the existence of non-trivial symmetries and show that under natural assumptions such a symmetry is semi-simple, i.e. is a scaling in some coordinates. Using the obtained results, we provide a complete classification of hexagonal singular 3-web germs in the complex plane, satisfying the following two conditions: 1) the Chern connection form is holomorphic at the singular point, 2) the web admits at least one infinitesimal symmetry at this point. As a by-product, a classification of hexagonal weighted homogeneous 3-webs is obtained.

Female paraurethral prostate gland in Bitches

Even though the presence of the female prostate has been reported in many species, including humans, bats and several rodents, it has many anatomical and histological variations. There is still plentiful discussion on the biological function of this organ. Many authors state that paraurethral ducts and glands are functional and homologous to the male prostate. The use of experimental models and a better knowledge of the female prostate gland in other species, can be useful to veterinary medicine as well as human medicine. Therefore the aim of this study is to check for the presence of this gland in female dogs of various breeds and age. For that purpose 25 urethras, from the bladder to the vulva, were collected, fixed in 10% neutral buffered formalin, routinely processed and sectioned into 4 slides of 4 µm, each with 40 µm gap between each set of 4 slides, using an automatic microtome and stained with Hematoxylin and Eosine (HE). The HE sections were evaluated for the presence of prostatic gland in the sample. Unstained tissue sections cut from paraffin blocks were marked with a polyclonal anti-PSA primary antibody. The prevalence of the gland was 32% (8/25). The structure of the paraurethral PSA-positive gland was acinar, organized in buds, with secretory epithelium varying from cubic to columnar; eccentric nuclei, with lose chromatin and a layer of basal cells, very similar to the male prostate were observed. In view of these characteristics, for the first time in the literature, was demonstrate that those glands. may be considered as female prostate in dogs, as they are in other vertebrates

Frequências de alimentação sobre o comportamento ingestivo, digestibilidade do amido e flutuação de consumo em bovinos Nelore confinados

Pós-graduação em Ciência e Tecnologia Animal - FEIS

Efeito das frequências de alimentação sobre o desempenho, características de carcaça e saúde ruminal de bovinos nelore confinados

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

Ce0.97Cu0.03O2 Nanocatalysts Synthesized via Microwave-assisted Hydrothermal Method: Characterization and CO-PROX Catalytic Efficiency

In the work presented here, Ce0.97Cu0.03O2 nanoparticles were synthesized by a microwave-assisted hydrothermal method under different synthesis temperatures. The obtained nanoparticles were tested as catalysts in preferential oxidation of CO to obtain CO-free H2 (PROX reaction). The samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), electron paramagnetic resonance spectroscopy (EPR) and temperature-programmed reduction (TPR). X-ray diffraction measurements detected the presence of pure cubic CeO2 for all synthesized samples. TEM images of the Ce0.97Cu0.03O2 nanoparticles revealed that samples synthesized at 80°C are composed mainly of nanospheres with an average size of 20 nm. The formation of some nanorods with an average diameter of 8 nm and 40 nm in length, and the size reduction of the nanoparticles from 20 to approximately 15 nm is observed with increasing synthesis temperature. EPR spectra indicated that copper is found well dispersed in sample synthesized at 160°C, located predominant in surface sites of ceria. For samples synthesized at 80 and 120°C, the species are less dispersed than in the other one, resulting in the formation of Cu2+−Cu2+ dimmers at the surface of ceria. TPR profiles presented two reduction peaks, one below 400°C attributed to the reduction of different copper species and a second peak around 800°C attributed to the reduction of Ce4+→ Ce3+ species located in the volume of the nanoparticles. The peak related to the reduction of copper species shifts to lower temperatures with increasing synthesis temperature, i.e., the sample synthesized at 160°C is more easily reduced than the ones synthesized at 120 and 80°C. The nanoparticles showed active as catalysts for the CO-PROX reaction. The microwave-assisted method revealed efficient for the synthesis of Ce0.97Cu0.03O2 nanoparticles with copper species selective for the CO-PROX reaction, which reaches CO conversions up to 92% for the sample synthesized at 160°C.

Microwave-assisted hydrothermal synthesis of NiO-Ce1-XEuxO2-δ powders for fuel cell catalytic anodes

CeO2-based materials doped with rare earth (TR +3) can be used as alternative to traditional NiO-YSZ anodes in solid oxide fuel cells as they have higher ionic conductivity and lower ohmic losses compared to YSZ. Moreover, they allow fuel cell operation at lower temperatures (500-800°C). In the anode composition, the concentration of NiO acting as catalyst in YSZ provides high electrical conductivity and high electrochemical activity of reactions, promoting internal reform in the cell. In this work, NiO - Ce1-xEuxO2-δ compounds (x = 0.1, 0.2 and 0.3) have been synthesized by microwave-assisted hydrothermal method. The materials were characterized by TG, XRD, TPR and SEM-FEG techniques. The refinement of data obtained by X-ray diffraction showed the presence of ceria doped with europium crystallized in a cubic phase with fluorite structure, in addition to the presence of NiO. The microwave-assisted hydrothermal method showed significant reduction in the average particle size and good mass control of phase compositions compared to other chemical synthesis techniques.

Influence of the preparation route on the structural, morphological and spectroscopic properties of SrTiO3 and SrTiO3:eu3+ powders

This research shows the influence of the synthesis route in the structural and morphological characteristics as well as in the luminescent properties of doped with europium and pure SrTiO3 (STO) powders prepared by microwave assisted hydrothermal synthesis, MWH, and by the polymeric precursor method, PPM. The XRD at room temperature of the STO powders nominally pure obtained by PPM at 700°C for 3 hours, as well as by the MWH at 190°C by 30 minutes present all the reflection peaks for the cubic perovskite structure (JCPDS-ICDD 35-734). The morphology varies according to the synthesis route. The particles of pure STO obtained by PPM presents morphology in the form of plates and the morphology of the particles synthesized by MWH is spherical with approximately 150 nm. The photoluminescent analysis shows for pure STO wide bands associated with the transition of charge transfer from the titanates group (TiO3)2- that are centered on 450 nm. In both preparation methods the emission bands obtained in the composites spectra were found to be asymmetric and low intense. However, in the case of the STO prepared by the PPM a bigger FWHM of the band can be observed. The excitation of the samples was done using a laser (Coherent Innova) with wavelength of 350 nm.

White Light and Multicolor Emission Tuning in Triply Doped Yb3+/Tm3+/Er3+ Novel Fluoro-phosphate Transparent Glass-ceramics

New Yb3+, Er3+ and Tm3+ doped fluoro-phosphate glasses belonging to the system NaPO3–YF3–BaF2–CaF2 and containing up to 10 wt% of rare-earth ion fluorides were prepared and characterized by differential scanning calorimetry, absorption spectroscopy and up-conversion emission spectroscopy under excitation with a 975 nm laser diode. Transparent and homogeneous glass-ceramics have been reproducibly obtained with a view to manage the red, green and blue emission bands and generate white light. X-ray diffraction as well as electron microscopy techniques have confirmed the formation of fluorite-type cubic nanocrystals at the beginning of the crystallization process while complex nanocrystalline phases are formed after a longer heat-treatment. The prepared glass-ceramics exhibit high optical transparency even after 170 h of thermal treatment. An improvement of up-conversion emission intensity – from 10 to 160 times larger – was measured in the glass-ceramics when compared to the parent glass, suggesting an important incorporation of the rare-earth ions into the crystalline phase(s). The involved mechanisms and lifetime were described in detail as a function of heat-treatment time. Finally, a large range of designable color rendering (from orange to turquoise through white) can be observed in these materials by controlling the laser excitation power and the crystallization rate.

Otimização do processamento de partículas lead-free para aplicação em compósitos polímero/cerâmica com propriedades piezoelétrica e fotoluminescente

Pós-graduação em Química - IQ

Um estudo teórico e experimental de nanoestruturas de 'ZnS': propriedades físicas e químicas

Pós-graduação em Química - IQ