Desenvolvimento de vasos digestores de amostra para microondas doméstico

The application of microwave radiation on the sample preparation has been expanding increasingly in areas involving decomposition by wet and dry roads, fusion, extraction, acceleration of chemical reactions, for example. Currently, the use of microwave ovens for analytical purposes are recognized for having excellent performance for organic and inorganic samples. In the international market there are several kinds of microwaves oven which adapt the varied purposes, however yet with elevated prices which incapacitate your use as routine equipment in laboratory. Thus, many researchers have been choosing for developing own projects of microwaves oven production or to use domestic oven for the laboratory, with or without adaptations. For the evaluation of the proposed method was used in the Kjeldahl methodology for determining total nitrogen in samples of crude protein, using a domestic microwave oven and a digester pot made up in TeflonTM and distillation by steam. Were made to adapt and characterization of a domestic microwave oven, the confeccion vessel digester and the metal support for the vessel. The accuracy of the proposed method was confirmed by comparison of two methods, the standard method for conventional heating and by the proposed method, with heating by microwave radiation through the calculated values of relative standard deviation analysis

Deslocamento de abomaso em vacas leiteiras

The genetic selection and the nutritional management to improve milk production make the dairy cattle more susceptible to the development of diseases, such as the abomasal displacement. It is the most frequently detected abomasal problem and it is the main cause of abdominal surgeries in dairy cattle. It is a multifactorial disease that occurs mainly in dairy cattle of high production during the puerperium. The abomasal displacement can occur to the right (DAD) or to the left (DAE), being the former more frequent than the latter. It is related to feeding management and occurs in animals that also have other diseases such as hypocalcaemia, ketosis and retained placenta. The disease causes economical losses in dairy cattle because of the costs with treatment, reduction of production, increase of the interval between the parturition, loss of body weight, early discard of the matrix and mortality. The most usual clinical signs are apathy, dehydration, low to serious ruminal timpanismo (gas accumulation in the abomasum) with reduction or lack of motility, liquid splash sound during the ballottement of the right flank, metallic sound to percussion, presence of a structure similar to distended viscera in the thorax or in the paralombar cavity on the side corresponding to the displacement, and liquefied, dark, scarce and fetid feces. The treatment is surgical, and the most used technique is the omentopexy on the left flank. The hidroelectrolytic correction must be performed and the concomitant diseases must be treated. The prophylaxis consists of adequate nutrition and pre-parturition management, besides reduction of stress and other diseases of the puerperium

Estudo de cerâmicas avançadas para fins de blindagem balística

The research involving new materials has always been considered as a differential in the development of a technology company. This occurred naturally since ancient times, often motivated by reasons of a certain age, where the most common material used was also the name of your time and may be cited as an example the Bronze Age, and later was the Iron. Currently, the use of firearms are they used in resolving conflicts between countries, or a more equivocal, as an instrument of social banditry make innovations in the area of shielding welcome, whether for personal use, in the form of vests or vehicle such as cars, tanks and even aircraft. In this context, is a Silicon Carbide Ceramic, with low density and high hardness. Thus, the aim of this study is the evaluation and comparison of these materials, seeking to improve their properties by means of additives such as boron and silicon metal and amorphous YAG. For this work, the specimens were pre-shaped by means of uniaxial later to be referred for isostatic pressing and sintering. The maximum percentage for each additive was 5%, except for the YAG whose percentage was 8.2% (mass percentage). All compositions were subjected to the same tests (x-ray diffraction, apparent density, optical microscopy, Vickers hardness, scanning electron Microscopita), so that one could draw a comparison between the materials under study, samples that showed better mechanical properties and micro structural, related here by hardness testing and microscopy (optical and SEM) were the silicon carbide doped with YAG and alumina samples, demonstrating the potential of these materials for ballistic protection. Other compositions have high porosity, which is highly undesirable, since in order to harmful influences on the mechanical properties discussed below

Caracterização estrutural da Liga Al-1% Si

The aim of this study is to characterize the macrostructure and microstructure of Al - 1%Si alloy obtained in sand and metallic molds. Aluminium has good mechanical properties, but adding silicon, even in small quantities, can change the microstructure and improves mechanical behavior. Workpieces were castings in metallic and sand molds and one can see a difference in their cooling curve, macroscopic and microscopic structures. The sand mold casting has lower cooling rate and so its grains are larger. Due to the lower concentration of grain boundary, the hardness is lower compared to that found in metallic molds, which has smaller grains and a higher hardness. Therefore, it can be concluded that the cooling rate and alloying elements affect the final microstructure of the workpiece

Análise da curva de resfriamento da liga de alumínio AA 356

It is very important to study the macrostructure of a material in the crude state of solidification due to influence the mechanical properties, as well as the study of their cooling curve. In the present work was to study the alloy AA 356, its macrostructure and its cooling curve. The material was cast in two different molds, a sand and other metallic. In this paper we study the differences in its macrostructure and its cooling curves. In macrostructure can observe the absence of the three zones of solidification and the presence of large pores because of moisture in the sand. In the sample taken from the metal mold can observe the three zones of solidification: a coquilhada, columnar and equiaxed

Estudo eletroquímico do sistema microestruturado montmorilonita-8- hidroxiquinolina na presença de íons metálicos

Pós-graduação em Química - IBILCE

Avaliação da Taxa de Exposição em Exames Radiológicos Realizados em Procedimentos Cirúrgicos - Minimização dos Riscos em Indivíduos Ocupacionalmente Expostos

This paper consists in the evaluation of the exposure rate to ionizing radiation to which professionals working in surgical procedures which require radiological examinations are subjected. Were initially performed real-time readings of exposure rate within four distinct operating rooms during the execution of four surgical procedures that made use of fluoroscopy equipment (including three orthopedic surgeries, one in the shoulder, one in the arm, another for deployment of metal pin in the leg region, and a fourth for vascular procedure); in these surgeries were used ionization chamber detector and an electrometer. In order to check the values achieved, was made a re-evaluation of the distribution of the rate of exposure to radiation, from the surgical procedures, now with thermoluminescent dosimeters (TLDs). For this, thirty TLDs were distributed in the operating rooms, arranged in points of interest as occupation by professionals. The TLDs were prepared for thirty consecutive days, after which they were removed and replaced with new dosimeters not exposed yet. The dosimeters were subjected to reading of the rate of exposure; this procedure was repeated for four months without interruption. The quantification of the results sought primarily to convert the rate of exposure for equivalent dose rate, both in measurements with ionization chamber as in measurements with TLDs, in order to highlight the presence of the biological effect of ionizing radiation for comparisons within scientific context. Then, the results were plotted to establish the relationship between the values of equivalent dose and the distance to the central axis of the x -ray source, confirming the inverse square law for distance. Finally, the values were associated with the maximum limit recommended by the legislation for occupationally exposed individuals. The methodology for the analysis and quantification of the data in this work aims at implementing a work plan that meets ...

Otimizando vibrações sísmicas em estruturas através de controles híbridos

Pós-graduação em Engenharia Mecânica - FEIS

Zero-valent iron mediated degradation of ciprofloxacin - Assessment of adsorption, operational parameters and degradation products

The zero-valent iron (ZVI) mediated degradation of the antibiotic ciprofloxacin (CIP) was studied under oxic condition. Operational parameters such as ZVI concentration and initial pH value were evaluated. Increase of the ZVI concentration from 1 to 5 g L−1 resulted in a sharp increase of the observed pseudo-first order rate constant of CIP degradation, reaching a plateau at around 10 g L−1. The contribution of adsorption to the overall removal of CIP and dissolved organic carbon (DOC) was evaluated after a procedure of acidification to pH 2.5 with sulfuric acid and sonication for 2 min. Adsorption increased as pH increased, while degradation decreased, showing that adsorption is not important for degradation. Contribution of adsorption was much more important for DOC removal than for CIP. Degradation of CIP resulted in partial defluorination since the fluoride measured corresponded to 34% of the theoretical value after 120 min of reaction. Analysis by liquid chromatography coupled to mass spectrometry showed the presence of products of hydroxylation on both piperazine and quinolonic rings generating fluorinated and defluorinated compounds as well as a product of the piperazine ring cleavage.

Diodo planar orgânico Schottky: construção e caracterização

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Filmes de 'CO' obtidos por deslocamento galvânico e suas propriedades magnéticas

Pós-graduação em Química - IQ

Preparação e caracterização de nanocompósitos de Fe@SiO2, Fe@Fe3O4 e Fe3O4@PNIPAM

Pós-graduação em Química - IQ

Avaliação da alteração dimensional de modelos obtidos a partir de moldagens com alginato tradicional e outro com desinfetante

The present study aims at evaluating dimensional alteration of stone casts made from impressions with a standard irreversible hydrocolloid and an antimicrobial one. For this, an alginate without disinfectant (Type II Jeltrate) and other containing chlorhexidine (Type II Avagel) were used, which rose by the same regime of treatment: without disinfection; immersion; and spraying. A 1% sodium hypochlorite solution was used for 10 minutes. To obtain the impressions, a perforated impression tray was made from a standard metal model. After molding, the molds were washed in running water for 30 seconds to simulate removal of saliva. Then, with the exception of the control group, these molds were subjected to disinfection treatment. After 10 minutes they were washed again. 60 samples poured with type V special gypsum (Durone) were obtained, that were measured 3 times in a stereomicroscope (SZX12, Olympus) to record the average of dimensional alterations. The disinfection treatment did not bring significant changes in the models obtained from both alginate tested (standard p = 0.7102; with chlorhexidine p = 0.5832). The results showed a statistically significant and additional advantage of the traditional alginate on alginate with chlorhexidine, with respect to dimensional alteration (p < 0.05).

Degradação dos fármacos ciprofloxacino e sertalina pelos processos ferro zero e foto-Fenton - aplicação em amostras de efluentes de estação de tratamento de esgoto

Pós-graduação em Química - IQ

Disposição construtiva aplicada em contenção ortodôntica

Disposição construtiva aplicada em contenção ortodôntica. Patente de modelo de utilidade para uma disposição construtiva aplicada em contenção ortodôntica, compreendida por ser do tipo 3x3, com encaixe do tipo "macho-fêmea", sendo que na base da "fêmea" (1) são procedidas retenções (2) mecânicas para fixação por meio de colagem na face lingual dos caninos (3) inferiores, com resina composta, de modo que no interior da "fêmea" (1) é provido um orifício (4) para o encaixe do "macho" (5) e, no centro da cavidade é provido um anel (6) elástico que se encaixa precisamente numa canaleta feita no pino (7) de encaixe do "macho" (5), sendo que, na extremidade dos "machos" (5) podem existir prolongamentos (8) metálicos para retenção de acrílico (9) ou então meios de encaixe para soldagem de um fio metálico (10) espesso, que contorna a face lingual dos dentes (11); inferiores anteriores, de modo que, quando se optar pela retenção em acrilico (9), um fio metálico (10) mais delgado é soldado no terminal de encaixe do "macho" (5) e logo após, o fio (10) e o terminal são recobertos por acrilico (9), sendo que os "machos" (5) poderão ter angulações nos braços (12) de encaixes.