15 resultados para rotary atomizer disk
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
ARAUJO, Afranio Cesar de et al. Síndromes de polinização ocorrentes em uma área de Mata Atlântica, Paraíba, Brasil. Biotemas, Florianopolis, v. 4, n. 22, p.83-94, dez. 2009. Disponível em:
Resumo:
Composite resins have been subjected to structural modifications aiming at improved optical and mechanical properties. The present study consisted in an in vitro evaluation of the staining behavior of two nanohybrid resins (NH1 and NH2), a nanoparticulated resin (NP) and a microhybrid resin (MH). Samples of these materials were prepared and immersed in commonly ingested drinks, i.e., coffee, red wine and acai berry for periods of time varying from 1 to 60 days. Cylindrical samples of each resin were shaped using a metallic die and polymerized during 30 s both on the bottom and top of its disk. All samples were polished and immersed in the staining solutions. After 24 hours, three samples of each resin immersed in each solution were removed and placed in a spectrofotome ter for analysis. To that end, the samples were previously diluted in HCl at 50%. Tukey tests were carried out in the statistical analysis of the results. The results revealed that there was a clear difference in the staining behavior of each material. The nanoparticulated resin did not show better color stability compared to the microhybrid resin. Moreover, all resins stained with time. The degree of staining decreased in the sequence nanoparticulated, microhybrid, nanohybrid MH2 and MH1. Wine was the most aggressive drink followed by coffee and acai berry. SEM and image analysis revealed significant porosity on the surface of MH resin and relatively large pores on a NP sample. The NH2 resin was characterized by homogeneous dispersion of particles and limited porosity. Finally, the NH1 resin depicted the lowest porosity level. The results revealed that staining is likely related to the concentration of inorganic pa rticles and surface porosity
Resumo:
Continuous Synthesis by Solution Combustion was employed in this work aiming to obtain tin dioxide nanostructured. Basically, a precursor solution is prepared and then be atomized and sprayed into the flame, where its combustion occurs, leading to the formation of particles. This is a recent technique that shows an enormous potential in oxides deposition, mainly by the low cost of equipment and precursors employed. The tin dioxide (SnO2) nanostructured has been widely used in various applications, especially as gas sensors and varistors. In the case of sensors based on semiconducting ceramics, where surface reactions are responsible for the detection of gases, the importance of surface area and particle size is even greater. The preference for a nanostructured material is based on its significant increase in surface area compared to conventional microcrystalline powders and small particle size, which may benefit certain properties such as high electrical conductivity, high thermal stability, mechanical and chemical. In this work, were employed as precursor solution tin chloride dehydrate diluted in anhydrous ethyl alcohol. Were utilized molar ratio chloride/solvent of 0,75 with the purpose of investigate its influence in the microstructure of produced powder. The solution precursor flux was 3 mL/min. Analysis with X-ray diffraction appointed that a solution precursor with molar ratio chloride/solvent of 0,75 leads to crystalline powder with single phase and all peaks are attributed to phase SnO2. Parameters as distance from the flame with atomizer distance from the capture system with the pilot, molar ratio and solution flux doesn t affect the presence of tin dioxide in the produced powder. In the characterization of the obtained powder techniques were used as thermogravimetric (TGA) and thermodiferential analysis (DTA), particle size by laser diffraction (GDL), crystallographic analysis by X-ray diffraction (XRD), morphology by scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) and electrical conductivity analysis. The techniques used revealed that the SnO2 exhibits behavior of a semiconductor material, and a potentially promising material for application as varistor and sensor systems for gas
Resumo:
The oil activity in the Rio Grande do Norte State (RN) is a permanent threat to coastal ecosystems, particularly mangroves, with the possibility of oil spills. In this context, the objective of this study was to evaluate the potential resistance of the mangrove environment of a possible spill. Were selected and isolated microorganisms degrading oil by the technique of enrichment cultures and formation of a bacterial consortium. The kinetic study of the consortium was held in rotary incubator shaken at 150 rpm and 30° C. Samples were taken at intervals of 4 hours for analysis of cell concentration and surface tension. The biodegradation was monitored using two methods of respirometry: manometric (OxiTop-C ®) and conductivimetry, where the biodegradation of oil was estimated indirectly by oxygen consumption and CO2 production, respectively. Furthermore, it was used a full 2² factorial design with triplicate at central point to the runs that used the conductivimetric methodology.. The technique of enrichment cultures allowed to obtain thirteen bacterial strains. Kinetic study of the consortium, we can showed the absence of the lag phase, reaching a maximum cell concentration of 2.55 g / L at 16 h of cultivation and a reduction on surface tension. When we adopted the methodology of OxiTop-C was detected a band indicating biodegradability (1% oil v/v), however when we used the conductivimetry methodology did not observe any band that would indicate effective biodegradation. By monitoring a process of biodegradation is necessary to observe the methodology will be adopted to evaluate the biodegradation process, since for the same conditions adopted different methodologies can produce different results. The oil-degrading isolates from soils of the mangrove estuary Potengi / RN are largely to be used in bioremediation strategies of these places, in the case of a possible oil spill, or it can be used in the treatment of waste oil generated in saline environments, since they are optimized the conditions of the tests so that the efficiency of biodegradation reach the minimum level suggested by the standarts
Resumo:
Biomass is considered the largest renewable energy source that can be used in an environmentally sustainable. From the pyrolysis of biomass is possible to obtain products with higher energy density and better use properties. The liquid resultant of this process is traditionally called bio-oil. The use of infrared burners in industrial applications has many advantages in terms of technical-operational, for example, uniformity in the heat supply in the form of radiation and convection, with a greater control of emissions due to the passage of exhaust gases through a macroporous ceramic bed. This paper presents a commercial infrared burner adapted with an ejector proposed able to burn a hybrid configuration of liquefied petroleum gas (LPG) and bio-oil diluted. The dilution of bio-oil with absolute ethanol aimed to decrease the viscosity of the fluid, and improving the stability and atomization. It was introduced a temperature controller with thermocouple modulating two stages (low heat / high heat), and solenoid valves for fuels supply. The infrared burner has been tested, being the diluted bio-oil atomized, and evaluated its performance by conducting energy balance. The method of thermodynamic analysis to estimate the load was used an aluminum plate located at the exit of combustion gases and the distribution of temperatures measured by thermocouples. The dilution reduced the viscosity of the bio-oil in 75.4% and increased by 11% the lower heating value (LHV) of the same, providing a stable combustion to the burner through the atomizing with compressed air and burns combined with LPG. Injecting the hybrid fuel there was increase in the heat transfer from the plate to the environment in 21.6% and gain useful benefit of 26.7%, due to the improved in the efficiency of the 1st Law of Thermodynamics of infrared burner
Resumo:
In a hospital environment, these bacteria can be spread by insects such as ants, which are characterized by high adaptability to the urban environment. Staphylococcus is a leading cause of hospital infection. In Europe, Latin America, USA and Canada, the group of coagulase negative staphylococci (CoNS) is the second leading cause of these infections, according to SENTRY (antimicrobial surveillance program- EUA). In this study, we investigated the potential of ants (Hymenoptera: Formicidae) as vehicle mechanics of Staphylococcus bacteria in a public hospital, in Natal-RN. The ants were collected, day and night, from June 2007 to may 2008, in the following sectors: hospitals, laundry, kitchen, blood bank. The ants were identified according to the identification key of Bolton, 1997. For the analysis of staphylococci, the ants were incubated in broth Tryptic Soy Broth (TSB) for 24 hours at 35 º C and then incubated on Mannitol Salt Agar. The typical colonies of staphylococci incubated for 24 hours at 35 ° C in Tryptic Soy Agar for the characterization tests (Gram stain, catalase, susceptibility to bacitracin and free coagulase). The identification of CoNS was performed through biochemical tests: susceptibility to novobiocin, growth under anaerobic conditions, presence of urease, the ornithine decarboxylation and acid production from the sugars mannose, maltose, trehalose, mannitol and xylose. The antimicrobial susceptibility examined by disk-diffusion technique. The technique of Polymerase Chain Reaction was used to confirm the presence of mecA gene and the ability to produce biofilm was verified by testing in vitro using polystyrene inert surface, in samples of resistant staphylococci. Among 440 ants, 85 (19.1%) were carrying coagulase-negative staphylococci (CoNS) of the species Staphylococcus saprophyticus (17), Staphylococcus epidermidis (15), Staphylococcus xylosus (13), Staphylococcus hominis hominis (10), Staphylococcus lugdunensis (10), Staphylococcus warneri (6), Staphylococcus cohnii urealyticum (5), Staphylococcus haemolyticus (3), Staphylococcus simulans (3), Staphylococcus cohnii cohnii (2), and Staphylococcus capitis (1). No Staphylococcus aureus was found. Among the isolates, 30.58% showed resistance to erythromycin. Two samples of CoNS (2.35%), obtained from the ant Tapinoma melanocephalum collected in the post-surgical female ward, S. Hominis hominis and S. lugdunensis harbored the mecA gene and were resistant to multiple antibiotics, and the specie S. hominis hominis even showed to be a biofilm producer. This study proves that ants act as carriers of multidrug-resistant coagulase-negative Staphylococci and biofilm producers and points to the risk of the spreading of pathogenic microorganisms by this insect in the hospital environment
Resumo:
All medicine, whether allopathic or homeopathic, must go through strict quality control, which must ratify their characteristics throughout the period of validity. During the time of preparation and storage, solutions of the drugs are in permanent contact with packaging materials that can release undesirable substances to the solution. Several factors may influence the release of packing materials, and factorial design (FD) is a useful tool for analyzing the phenomenon. The aim of this study was the determination of quality parameters for Homeopathic solid (globules) and liquid (drops) dosage forms. It was carried out analysis in homeopathic globules for weight variation, mechanical strength, and moisture content uniformity. For liquid preparations, standard solutions were prepared from natural rubber bulbs, which were subjected to exhaustive extraction with two ethanol solutions (30 and 70%) in the ultrasonic bath for 20 minutes at 25°C and 50°C in three successive cycles. Studies of transfer have been made within five days, by spectrophotometric analysis in the UV region at 312 nm with λmáx and 323 nm for samples in 70% ethanol and 30% respectively. PH values were analyzed. We also conducted two FD studies, where the first, the three-level variables were solvent (chloroform, ethanol and nhexane), sample mass (30, 60 and 90mg), particle size (large disk, small disk and powder sample). In the second study, the solvent level variables were different ethanolic degrees (EtOH 30%, 70% and pure). The percentage of lending in the solutions was 5.5%, 12.4%, 24.2% and 41% of the total estimated in the reference solution. The values of rate constants of transfer were determined in the order of 0.0134 days-1 and 0.0232 days-1 in absorbance values, the solutions in ethanol at 30% and 70% respectively. These results suggest that the speed of transfer of materials from rubber is affected both by the nature of the vehicle as by the temperature
Resumo:
The present work shows the development and construction of a robot manipulator with two rotary joints and two degrees of freedom, driven by three-phase induction motors. The positions of the arm and base are made, for comparison, by a fuzzy controller and a PID controller implemented in LabVIEW® programming environment. The robot manipulator moves in an area equivalent to a quarter of a sphere. Experimental results have shown that the fuzzy controller has superior performance to PID controller when tracking single and multiple step trajectories, for the cases of load and no load
Resumo:
Due to advances in the manufacturing process of orthopedic prostheses, the need for better quality shape reading techniques (i.e. with less uncertainty) of the residual limb of amputees became a challenge. To overcome these problems means to be able in obtaining accurate geometry information of the limb and, consequently, better manufacturing processes of both transfemural and transtibial prosthetic sockets. The key point for this task is to customize these readings trying to be as faithful as possible to the real profile of each patient. Within this context, firstly two prototype versions (α and β) of a 3D mechanical scanner for reading residual limbs shape based on reverse engineering techniques were designed. Prototype β is an improved version of prototype α, despite remaining working in analogical mode. Both prototypes are capable of producing a CAD representation of the limb via appropriated graphical sheets and were conceived to work purely by mechanical means. The first results were encouraging as they were able to achieve a great decrease concerning the degree of uncertainty of measurements when compared to traditional methods that are very inaccurate and outdated. For instance, it's not unusual to see these archaic methods in action by making use of ordinary home kind measure-tapes for exploring the limb's shape. Although prototype β improved the readings, it still required someone to input the plotted points (i.e. those marked in disk shape graphical sheets) to an academic CAD software called OrtoCAD. This task is performed by manual typing which is time consuming and carries very limited reliability. Furthermore, the number of coordinates obtained from the purely mechanical system is limited to sub-divisions of the graphical sheet (it records a point every 10 degrees with a resolution of one millimeter). These drawbacks were overcome by designing the second release of prototype β in which it was developed an electronic variation of the reading table components now capable of performing an automatic reading (i.e. no human intervention in digital mode). An interface software (i.e. drive) was built to facilitate data transfer. Much better results were obtained meaning less degree of uncertainty (it records a point every 2 degrees with a resolution of 1/10 mm). Additionally, it was proposed an algorithm to convert the CAD geometry, used by OrtoCAD, to an appropriate format and enabling the use of rapid prototyping equipment aiming future automation of the manufacturing process of prosthetic sockets.
Resumo:
The rotary dryer is one of the most used equipments in processing industries. Its automatic control mode of operation is important specially to keep the moisture content of the final product in the desired value. The classical control strategies, like PID (proportional integral derivative) control, are largely used in the industrial sector because of its robustness and because they are easy to be implemented. In this work, a data acquisition system was implemented for monitoring the most relevant process variables, like: both inlet and outlet drying air temperature, dryer rotation, outlet air speed and humidity, and mass of the final product. Openloop tests were realized to identify a mathematical model able to represent the drying process for the rotary system. From this model, a PID controller was tuned using a direct synthesis method, assuming a first order trajectory. The PID controller was implemented in the system in order to control the inlet drying air temperature. By the end, closedloop tests (operating in automatic mode) were realized to observe the controller performance, and, after setting the best tune, experiments were realized using passion fruit seeds as raw material. The experiments realized in closedloop showed a satisfactory performance by the implemented control strategy for the drying air temperature of the rotary system
Resumo:
Visceral leishmaniosis caused by Leishmania chagasi, also known as calazar, presented, in the period from 1990 to 2005, tax of incidence in Brazil varying between 1 and 3 cases for 100 000 inhabitants. The Northeast region that up to the year of 2000 contributed with almost 90% of the registered cases is reducing his participation in the current decade, reaching 56% in 2005. Conventional leishmaniasis treatment is costly and it shows high toxicity, demanding more research for alternative treatments, with special interest in development of vaccines and diagnosis kits which include production of recombinant antigens by host cells. Escherichia coli has been the microorganism most studied and used as a host for recombinant protein production. Therefore, the aim of this work was to study the influence of induction on cellular growth and to verify the type of Leishmania chagasi antigens expression (intra or extracellular) during two recombinant E. coli clones (kmp11 and P36) cultivation in rotary incubator (shaker) using three different media (2xTY, TB, FASS+EL). For that, tests were carried out using conditions established in the literature for E. coli (37°C and 200 rpm) and media supplemented with antibiotics to guarantee that only competent cells grows. First, tests were carried out without induction in order to verify the two microorganisms kinetic behavior (growth and substrate consumption) in different media. Next, the induction was carried out through the addition of IPTG (1mM as final concentration), at the first hour of cultivation. It was observed that protein expression were intracellular for all clones and media tested, however the highest level of expression was clearly observed by the electrophoresis band density (intensity) for 2xTY medium and kmp11 protein. Although it contains the lowest substrate concentration, consequently, a reduced cellular concentration when compared to other media, it appeared that this medium and clone combination is the most indicated for recombinant protein production. Therefore, the objective of this work was achieved, since the interested proteins were produced. Consequently, this result motivates new studies for production optimization using different cultivation strategies
Resumo:
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
Resumo:
Some studies reported in the literature that emotional factors and quality of life may be involved both in aetiology, as in the progression of Temporomandibular disorders (TMD). Proposition: The purpose of this study is to observe a possible association between different forms of anxiety, quality of life and general health of patients diagnosed as carriers of various types and levels of Temporomandibular Dysfunction. Methodology: The sample consisted of 60 patients diagnosed as carriers of TMJD origin of muscle, joint, or both, with different levels of severity (mild TMD, moderate and severe). The patients were diagnosed with TMD-RDC (Research Diagnostic Criteria) to assess the type of dysfunction (muscle or joint) and by the Protocol of Fonseca to verify the degree of dysfunction (mild, moderate or severe). To evaluate the psychosocial aspects were used three self-applied, with the purpose of obtaining information about the general health (General Health Questionnaire - GHQ), the type of anxiety (Trait Anxiety Inventory-State - STAI) and quality of life (World Health Organization Quality Of Life Short WHOQOL-brief). Results: There was a correlation between all indicators studied in several forms of TMD with varying degrees of commitment. Quality of life appeared linked to the type and the level of TMD: Muscular and Articular TMD (p = 0,037), Disk Displacement With Reduction (p = 0.01) and Mild TMD (p = 0.042). The General Health showed association with the level of TMD, with the exception of the stress factor (p = 0.78). For the analysis of the types and levels to Severe Muscular TMD had a statistically significant indicator of the quality of life (p = 0049). The anxiety only showed association with the level of TMD (p = 0,047 for anxiety-trait). Conclusion: Besides the limitations of the study, it was concluded that anxiety, quality of life and general health are important psychosocial indicators, which are linked to several forms of TMD in different levels of severity
Resumo:
Many pollutants dumped in waterways, such as dyes and pesticides, have become so ubiquitous that they represent a serious threat to human health. The electrochemical oxidation is presented as an alternative clean, efficient and economic degradation of wastewater containing organic compounds and a number of advantages of this technique is to just not make use of chemical reagents, since only electrical energy is consumed during the removal of pollutants organic. However, despite being a promising alternative, still needs some tweaking in order to obtain better efficiency in the elimination of persistent pollutants. Thus, this study sought a relationship between a recently discovered phenomenon that reflects the participation of dissolved oxygen in solution in the electrochemical oxidation process, as an anomaly, present a kinetic model that shows instantaneous current efficiency (ICE) above 100% limited by theory, manifested for some experiments with phenolic compounds with H2SO4 or HClO4 as supporting electrolyte with electrodes under anodic oxidation on boron doped diamond (BDD). Therefore it was necessary to reproduce the data ICE exposes the fault model, and thus the 2-naphthol was used as phenolic compound to be oxidised at concentrations of 9, 12 and 15 mmol L-1, and H2SO4 and HClO4 to 1 mol L-1 as a supporting electrolyte under a current density of 30 mA cm-2 in an electrochemical reactor for continuous flow disk configuration, and equipped with anodes DDB at room temperature (25 oC). Experiments were performed using N2 like as purge gas for eliminate oxygen dissolved in solution so that its influence in the system was studied. After exposure of the anomaly of the ICE model and investigation of its relationship with dissolved O2, the data could be treated, making it possible for confirmation. But not only that, the data obtained from eletranálise and spectroscopic analysis suggest the involvement of other strongly oxidizing species (O3 (ozone) and O radicals and O2 -), since the dissolved O2 can be consumed during the formation of new strong oxidizing species, not considered until now, something that needs to be investigated by more accurate methods that we may know a little more of this system. Currently the performance of the electrocatalytic process is established by a complex interaction between different parameters that can be optimized, so it is necessary to the implementation of theoretical models, which are the conceptual lens with which researchers see
Resumo:
Nowadays several electronics devices support digital videos. Some examples of these devices are cellphones, digital cameras, video cameras and digital televisions. However, raw videos present a huge amount of data, millions of bits, for their representation as the way they were captured. To store them in its primary form it would be necessary a huge amount of disk space and a huge bandwidth to allow the transmission of these data. The video compression becomes essential to make possible information storage and transmission. Motion Estimation is a technique used in the video coder that explores the temporal redundancy present in video sequences to reduce the amount of data necessary to represent the information. This work presents a hardware architecture of a motion estimation module for high resolution videos according to H.264/AVC standard. The H.264/AVC is the most advanced video coder standard, with several new features which allow it to achieve high compression rates. The architecture presented in this work was developed to provide a high data reuse. The data reuse schema adopted reduces the bandwidth required to execute motion estimation. The motion estimation is the task responsible for the largest share of the gains obtained with the H.264/AVC standard so this module is essential for final video coder performance. This work is included in Rede H.264 project which aims to develop Brazilian technology for Brazilian System of Digital Television