Uma avaliação comparativa de estratégias de arranjos físicos para estaleiros de construção de embarcações metálicas de pequeno porte

The present study aims to analyse, in different levels of demand, what is the best layout strategy to adopt for the small metallic shipbuilding. To achieve this purpose, three simulation models are developed for analyze these production strategies under the positional, cellular and linear layouts. By the use of a simulation tool for compare the scenarios, Chwif and Medina (2010) and Law (2009)´s methodologies were adapted that includes three phases: conception, implementation and analysis. In conception real systems were represented by process mapping according to time, material resources and human resources variables required for each step of the production process. All of this information has been transformed in the cost variable. Data were collected from three different production systems, two located in Natal RN with cellular and positional layouts and one located in Belém-PA with linear layout. In the implementation phase, the conceptual models were converted in computacional models through the tool Rockwell Software Arena ® 13.5 and then validated. In the analysis stage the production of 960 ships in a year vessels were simulated for each layout noting that, for a production of until 80 units positional layout is the most recommended, between 81 and 288 units the cellular layout and more than 289 units the linear layout

Avaliação de robustez, desempenho e aplicação do controlador adaptativo por posicionamento de pólos e estrutura variável

In this work, the variable structure adaptive pole placement controller (VS-APPC) robustness and performance are evaluated and this algorithm is applied in a motor control system. The controller robustness evaluation will be done through simulations, where will be introduced in the system the following adversities: time delay, actuator response boundeds, disturbances, parametric variation and unmodeled dynamics. The VS-APPC will be compared with PI control, pole placement control (PPC) and adaptive pole placement controller (APPC). The VS-APPC will be simulated to track a step and a sine reference. It will be applied in a three-phase induction motor control system to track a sine signal in the stator reference frame. Simulation and experimental results will prove the efficiency and robustness of this control strategy

Extração enzimática de óleo e produção in situ de biodiesel a partir da Moringa oleífera Lam

With the growth and development of modern society, arises the need to search for new raw materials and new technologies which present the "clean" characteristic, and do not harm the environment, but can join the energy needs of industry and transportation. The Moringa oleifera Lam, plant originating from India, and currently present in the Brazilian Northeast, presents itself as a multi-purpose plant, can be used as a coagulant in water treatment, as a natural remedy and as a feedstock for biodiesel production. In this work, Moringa has been used as a raw material for studies on the extraction and subsequently in the synthesis of biodiesel. Studies have been conducted on various techniques of Moringa oil extraction (solvents, mechanical pressing and enzymatic), being specially developed an experimental design for the aqueous extraction with the aid of the enzyme Neutrase© 0.8 L, with the aim of analyzing the influence variable pH (5.5-7.5), temperature (45-55°C), time (16-24 hours) and amount of catalyst (2-5%) on the extraction yield. In relation to study of the synthesis of biodiesel was initially carried out a conventional transesterification (50°C, KOH as a catalyst, methanol and 60 minutes reaction). Next, a study was conducted using the technique of in situ transesterification by using an experimental design variables as temperature (30-60°C), catalyst amount (2-5%), and molar ratio oil / ethanol (1:420-1:600). The extraction technique that achieved the highest extraction yield (35%) was the one that used hexane as a solvent. The extraction using 32% ethanol obtained by mechanical pressing and extraction reached 25% yield. For the enzymatic extraction, the experimental design indicated that the extraction yield was most affected by the effect of the combination of temperature and time. The maximum yield obtained in this extraction was 16%. After the step of obtaining the oil was accomplished the synthesis of biodiesel by the conventional method and the in situ technique. The method of conventional transesterification was obtained a content of 100% and esters by in situ technique was also obtained in 100% in the experimental point 7, with a molar ratio oil / alcohol 1:420, Temperature 60°C in 5% weight KOH with the reaction time of 1.5 h. By the experimental design, it was found that the variable that most influenced the ester content was late the percentage of catalyst. By physico-chemical analysis it was observed that the biodiesel produced by the in situ method fell within the rules of the ANP, therefore this technique feasible, because does not require the preliminary stage of oil extraction and achieves high levels of esters

Avaliação da flotação por ar dissolvido no polimento de efluentes de lagoa de estabilização

Experience in the use of stabilization ponds shows that this is a system with low cost, easy operation and maintenance and suitable for tropical countries. One of its disadvantages is due to high concentrations of suspended solids, mainly due to algal biomass in the effluents. Accordingly, the dissolved air flotation has been shown to be an efficient post-treatment technology. However, the efficiency of this process is related to coagulation and flocculation steps, as well as the adjustment of the involved variables in the process. The objective of this work was to evaluate the algae removal efficiency from wastewater stabilization ponds and the influence of the factors involved in the process using dissolved air flotation. For this, we used primary facultative and maturation effluents of ETE Ponta Negra in Natal. We did tests of coagulation, flocculation and flotation with the samples, using the equipment flotatest. In this process were tested coagulants aluminum sulfate and ferric chloride, and varied the factors pH, coagulant concentration, polymer concentration and rate of recirculation. At the end of the experiments were analyzed turbidity, suspended solids, color, COD and chlorophyll "a". These results were submitted to descriptive statistics to verify the efficiency of the process in general, and regression analysis to identify models that describe the process and demonstrate the factors that have greater influence on flotation. After step methodology, high values were found removal efficiency of suspended solids, reaching values greater than 90% in the best cases. It was concluded that flotation is more efficient in the facultative pond effluent using ferric chloride, and the variability of algae may negatively influence the process. Regression analyzes showed that pH is the most influential variable in the coagulation-flocculation-flotation, and its optimal value among the tested is 5.5 for both coagulants

Influência do biofeedback no treino de marcha de sujeitos hemiparéticos: ensaio clínico randomizado

BACKGROUND: Treadmill training with partial body weight support (BWS) has shown many benefits for patients after a stroke. But their findings are not well known when combined with biofeedback. OBJETIVE: The purpose of this study was to evaluate the immediate effects of biofeedback, visual and auditory, combined with treadmill training with BWS on on walking functions of hemiplegic subjects. METHODS: We conducted a clinical trial, randomized controlled trial with 30 subjects in the chronic stage of stroke, underwent treadmill training with BWS (control), combined with visual biofeedback, given by the monitor of the treadmill through the symbolic appearance of feet as the subject gave the step; or auditory biofeedback, using a metronome with a frequency of 115% of the cadence of the individual. The subjects were evaluated by kinematics, and the data obtained by the Motion Analysis System Qualisys. To assess differences between groups and within each group after training was applied to ANOVA 3 x 2 repeated measures. RESULTS: There were no statistical differences between groups in any variable spatio-temporal and angular motion, but within each group there was an increase in walking speed and stride length after the training. The group of visual biofeedback increased the stance period and reduced the swing period and reason of symmetry, and the group auditory biofeedback reduced the double stance period. The range of motion of the knee and ankle and the plantar flexion increased in the visual biofeedback group. CONCLUSION: There are no differences between the immediate effects of gait training on a treadmill with BWS performed with and without visual or auditory biofeedback. However, the visual biofeedback can promote changes in a larger number of variables spatiotemporal and angular gait

Implementação Hardware/Software da estimação de movimento segundo o padrão H.264

Motion estimation is the main responsible for data reduction in digital video encoding. It is also the most computational damanding step. H.264 is the newest standard for video compression and was planned to double the compression ratio achievied by previous standards. It was developed by the ITU-T Video Coding Experts Group (VCEG) together with the ISO/IEC Moving Picture Experts Group (MPEG) as the product of a partnership effort known as the Joint Video Team (JVT). H.264 presents novelties that improve the motion estimation efficiency, such as the adoption of variable block-size, quarter pixel precision and multiple reference frames. This work defines an architecture for motion estimation in hardware/software, using a full search algorithm, variable block-size and mode decision. This work consider the use of reconfigurable devices, soft-processors and development tools for embedded systems such as Quartus II, SOPC Builder, Nios II and ModelSim

Reavaliação de critérios estruturais na hidrogeologia de terrenos cristalinos, com ênfase na neotectônica e sensoriamento remoto

Hydrogeological prospecting in Northeast Brazil and in other crystalline terrains has been developed on the basis of structural and regional geology concepts that date back to the 50-60 decades and, as such, demand a natural re-evaluation and update. In this kind of terrain, the percolation and accumulation of ground water are controlled by fractures and other types of discontinuities, such as foliations and geological contacts that, through weathering, impart porosity and permeability to the rocks, allowing water flow and storage. Several factors should be considered in the process of locating water wells, as discussed in the literature. Among these, the kind of structures, fracture geometry (including aperture and connectivity) and their geological and chronological context. It is important to correlate fracture systems with the regional neotectonic framework. Fractures at low angle (sub parallel) with the principal stress axis (s1) are those which tend to open (actually they work as tension joints) and, in principle, would present major hydric potential; in the opposite side, fractures at high angle to s1 would behave as closed by a compressional component. Fractures diagonal to the compression and tension axes correspond to shear fractures and, due to their connectivity with second fractures, are also important in terms of hydric potential. Uplift followed by terrain denudation leads to decompression and a general tendency to open (aided by weathering processes) fractures and other rock discontinuities, at different orientations. Low angle fractures, formed in this context, are equally important to increase connectivity, collection of water and recharge of the aquifer systems. In a general way, an opening component (neotectonic or by terrain decompression) and several models to increase fracture connectivity correlate with a greater hydric potential of these structures. Together with parallel research, this thesis addresses models of ground water occurrence in crystalline terrains, either improving well established concepts like the (Riacho-Fenda model), but also stressing other possibilities, like the role of alluvium and paleo-regoliths (the Calha Elúvio-Aluvionar model) and of strongly altered, permo-porous zones placed at variable depths below the present surface, flanking several types of discontinuities, especially interconnected fracture arrays (the Bolsões de Intemperismo model). Different methodological approaches are also discussed in order to improve success rates in the location of water wells in crystalline terrains. In this methodological review, a number of case studies were selected in the eastern domain of the State of Rio Grande do Norte, involving the localities of Santa Cruz, Santo Antônio, Serrinha, Nova Cruz, Montanhas, Lagoa de Pedras and Lagoa Salgada. Besides the neotectonic analysis of brittle structures, this Thesis addresses the validation of remote sensing as a tool for ground water prospecting. Several techniques were tested in order to detect and select areas with higher potential for ground water accumulation, using Landsat 5-TM and RADARSAT images, besides conventional aerial photos. A number of filters were tested to emphasize lineaments in the images, improving their discrimination, to identify areas with higher overburden humidity, which could reflect subsurface water accumulation, as well as alluvium and other sedimentary covers that might act as recharge zones. The work started with a regional analysis with the orbital images, followed by analysis of aerial photos, up to a detailed structural study of rock exposures in the terrain. This last step involved the analysis of outcrops surrounding wells (in a ray of approximately 10 to 100 m) with distinct productivities, including dry examples. At the level required for detail, it was not possible to accomplish a statistical approach using the available well data catalogs, which lack the desired specific information. The methodology worked out in this Thesis must undergo a testing phase through location of new water wells. An increase in the success rates as desired will led to a further consolidation step with wider divulgation of the methodology to private companies and governmental agencies involved in ground water prospecting in crystalline terrains