937 resultados para 091301 Acoustics and Noise Control (excl. Architectural Acoustics)
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This study aimed to evaluate the efficiency of natural biocides, brown and green propolis, for the control of bacterial contamination in the production of sugarcane spirit. The treatments consisted of brown and green propolis extracts, ampicillin, and a control and were assessed at the beginning and end of harvest season in ten fermentation cycles. In the microbiological analyses, the lactic acid bacteria were quantified in the inoculum before and after the treatment with biocides, and the viability of yeast cells during fermentation was evaluated. The levels of acids, glycerol, total residual reducing sugars, and ethanol were analyzed for the wine resulting from each fermentation cycle. A reduction in the number of bacterial contaminants in the inoculum in the treatments with the natural biocides was observed, but it did not affect the viability of yeast cells. The control of the contaminants led to the production of higher levels of ethanol and reduced acidity in the wine produced. The results of the use of brown and green propolis to control the growth microorganisms in the fermentation of sugarcane spirit can be of great importance for using alternative strategies to synthetic antibacterials in fermentation processes including other distilled beverage or spirits.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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the aims of this study were to determine imazapyr efficacy for floating macrophyte control and ecotoxicology for non-target organisms. For the floating macrophyte control efficacy tests were used the doses of 0,5; 1,0; 2,0; 2,5; 3,0; 3,5 and 4,0 L ha(-1) and a control with 10 replicates. The acute toxicology for non-target organisms was estimated by lethal concentration 50% (LC50 and EC50). The floating macrophyte control efficacy was over 90%. Imazapyr was classified as moderately toxic for the following biomarkers: L. minor, H. eques, B. rerio, P. caudimaculatus, P. canaliculata, and P. mesopotamicus and lightly toxic for A. caroliniana. Thus, imazapyr herbicide is a tool with great potential to be used on floating macrophyte control (E. crassipes, P. stratiotes e S. molesta) in Brazil and this practice can be evaluated by the use of application biomarkers.
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In this work a Nonzero-Sum NASH game related to the H2 and H∞ control problems is formulated in the context of convex optimization theory. The variables of the game are limiting bounds for the H2 and H∞ norms, and the final controller is obtained as an equilibrium solution, which minimizes the `sensitivity of each norm' with respect to the other. The state feedback problem is considered and illustrated by numerical examples.
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A robotic control design considering all the inherent nonlinearities of the robot engine configuration is developed. The interactions between the robot and joint motor drive mechanism are considered. The proposed control combines two strategies, one feedforward control in order to maintain the system in the desired coordinate, and feedback control system to take the system into a desired coordinate. The feedback control is obtained using State Dependent Riccati Equation (SDRE). For link positioning two cases are considered. Case 1: For control positioning, it is only used motor voltage; Case 2: For control positioning, it is used both motor voltage and torque between the links. Simulation results, including parametric uncertainties in control shows the feasibility of the proposed control for the considered system.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Many rural communities are experiencing population decline. However, rural residents have continued to show a strong attachment to their communities. How do rural Nebraskans feel about their community? Are they satisfied with the services provided? Do they own their home? What is the condition of their home? This report details 2,851 responses to the 2005 Nebraska Rural Poll, the tenth annual effort to understand rural Nebraskans’ perceptions. Respondents were asked a series of questions about their community and housing. Trends for some of these questions are examined by comparing data from the nine previous polls to this year’s results. For all questions, comparisons are made among different respondent subgroups, that is, comparisons by age, occupation, region, etc. Based on these analyses, some key findings emerged: Rural Nebraskans’ views of the change in their community are similar to those expressed last year. This year, 28 percent believe their community has changed for the better, compared to 26 percent last year. And, in 2005, only 20 percent think their community has changed for the worse, compared to 22 percent last year. The proportion of expected movers who plan to leave the state decreased this year. Last year, 56 percent of the persons planning to move from their community expected to leave the state. That proportion decreased to 47 percent this year. Rural Nebraskans living in or near the largest communities are more likely than persons living in or near the smaller communities to say their community has changed for the better. Thirty-nine percent of persons living in or near communities with populations of 10,000 or more believe their community has changed for the better during the past year, but only 15 percent of persons living in or near communities with less than 500 people share this opinion. The community services and amenities that rural Nebraskans are most dissatisfied with include: entertainment, retail shopping and restaurants. At least one-third of rural Nebraskans express dissatisfaction with these three services. They are most satisfied with parks and recreation, library services, basic medical care services, highways and bridges, and education (K - 12). At least one-half of rural Nebraskans are satisfied with the following items in their community: appearance of residential areas (66%), crime control (61%), maintenance of sidewalks and public areas (57%) and noise (54%). Rural Nebraskans generally have positive views about their community. Sixty percent agree that their community is an ideal place to live and 52 percent say their community has good business leaders. Rural Nebraskans have mixed opinions about the future of their community. Fortyfour percent agree that their community’s future looks bright, but 42 percent disagree with this statement. Fourteen percent have no opinion. Rural Nebraskans living in or near the larger communities are more likely than residents of the smaller communities to think their community’s future looks bright. Fifty-nine percent of persons living in or near communities with populations of 10,000 or more agree with this statement, compared to only 25 percent of residents living in or near communities with less than 500 people. Further, 61 percent of the residents of the smallest communities disagree with this statement, compared to only 28 percent of the residents of the largest communities. Over three-quarters of rural Nebraskans disagree that younger residents of their community tend to stay there after completing high school. Seventy-six percent disagree with this statement, 16 percent have no opinion and eight percent agree that younger residents stay after completing high school. When comparing responses by age, younger persons are more likely than older persons to agree that younger residents stay in their community after high school. Sixteen percent of persons age 19 to 29 agree with this statement, compared to only six percent of persons age 50 to 64. Younger persons are more likely than older persons to be planning to move from their community next year. Fifteen percent of persons between the ages of 19 and 29 are planning to move next year, compared to only two percent of persons age 65 and older. An additional 17 percent of the younger respondents indicate they are uncertain if they plan to move. Most rural Nebraskans own their home. Eighty-four percent of rural Nebraskans own their home. Older persons are more likely than younger persons to own their home. Eighty-eight percent of persons over the age of 50 own their home, compared to only 52 percent of persons age 19 to 29. Housing in rural Nebraska has an average age of 50 years. Twenty-four percent of residences were built before 1930. Another 24 percent were built between 1930 and 1959. Twenty-nine percent were built between 1960 and 1979 and the remaining 24 percent were built in 1980 or later. The housing stock in smaller communities is older than the housing located in larger communities. Over one-third (35%) of the residences in communities with less than 1,000 people were built before 1930. Only 12 percent of the homes in communities with populations of 10,000 or more were built in this time period. Most rural Nebraskans appear satisfied with their home. Only 24 percent say the current size of their home does not meet their needs. The same proportion (24%) say their home is in need of major repairs. Thirty-eight percent agree that their home needs a lot of routine maintenance, but 87 percent like the location (neighborhood) of their home. One-third of rural Nebraskans living in or near the smallest communities say their home is in need of major repairs. Only 19 percent of persons living in or near communities with populations of 5,000 or more are facing this problem. Home ownership is very important to most rural Nebraskans. Eighty-two percent believe it is very important to own their home. An additional 12 percent say it is somewhat important and six percent say it is not at all important. However, persons who do not currently own their home do not feel it is important for them to do so. Only 32 percent of renters say it is very important to own their home, compared to 91 percent of home owners. And, 35 percent of renters say it is not at all important to own their home.
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Background: Over the last century the incidence of cutaneous melanoma has increased worldwide, a trend that has also been observed in Brazil. The identified risk factors for melanoma include the pattern of sun exposure, family history, and certain phenotypic features. In addition, the incidence of melanoma might be influenced by ethnicity. Like many countries, Brazil has high immigration rates and consequently a heterogenous population. However, Brazil is unique among such countries in that the ethnic heterogeneity of its population is primarily attributable to admixture. This study aimed to evaluate the contribution of European ethnicity to the risk of cutaneous melanoma in Brazil. Methodology/Principal Findings: We carried out a hospital-based case-control study in the metropolitan area of Sao Paulo, Brazil. We evaluated 424 hospitalized patients (202 melanoma patients and 222 control patients) regarding phenotypic features, sun exposure, and number of grandparents born in Europe. Through multivariate logistic regression analysis, we found the following variables to be independently associated with melanoma: grandparents born in Europe-Spain (OR = 3.01, 95% CI: 1.03-8.77), Italy (OR = 3.47, 95% CI: 1.41-8.57), a Germanic/Slavic country (OR = 3.06, 95% CI: 1.05-8.93), or >= 2 European countries (OR = 2.82, 95% CI: 1.06-7.47); eye color-light brown (OR = 1.99, 95% CI: 1.14-3.84) and green/blue (OR = 4.62; 95% CI 2.22-9.58); pigmented lesion removal (OR = 3.78; 95% CI: 2.21-6.49); no lifetime sunscreen use (OR = 3.08; 95% CI: 1.03-9.22); and lifetime severe sunburn (OR = 1.81; 95% CI: 1.03-3.19). Conclusions: Our results indicate that European ancestry is a risk factor for cutaneous melanoma. Such risk appears to be related not only to skin type, eye color, and tanning capacity but also to others specific characteristics of European populations introduced in the New World by European immigrants.
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The objective of this study is to investigate cardiac bioeffects resulting from ultrasonic stimulation using a specific set of acoustical parameters. Ten Sprague-Dawley rats were anesthetized and exposed to 1-MHz ultrasound pulses of 3-MPa peak rarefactional pressure and approximately 1% duty factor. The pulse repetition frequency started slightly above the heart rate and was decreased by 1 Hz every 10 s, for a total exposure duration of 30 s. The control group was composed of five rats. Two-way analysis of variance for repeated measures and Bonferroni post hoc tests were used to compare heart rate and ejection fraction, which was used as an index of myocardial contractility. It was demonstrated for the first time that transthoracic ultrasound has the potential to decrease the heart rate by similar to 20%. The negative chronotropic effect lasted for at least 15 min after ultrasound exposure and there was no apparent gross damage to the cardiac tissue.
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In this work, we present a numerical study of the use of reconfigurable arrays (RCA) for vibro-acoustography (VA) beam formation. A parametric study of the aperture selection, number of channels, number of elements, focal distance, and steering parameters is presented to show the feasibility and evaluate the performance of VA imaging based on RCA. The transducer aperture was based on two concentric arrays driven by two continuous-wave or toneburst signals at slightly different frequencies. The mathematical model considers a homogeneous, isotropic, inviscid medium. The point-spread function of the system is calculated based on angular spectrum methods using the Fresnel approximation for rectangular sources. Simulations considering arrays with 50 x 50 to 200 x 200 elements with number of channels varying in the range of 32 to 128 are evaluated to identify the best configuration for VA. Advantages of two-dimensional and RCA arrays and aspects related to clinical importance of the RCA implementation in VA, such as spatial resolution, image frame rate, and commercial machine implementation, are discussed. It is concluded that RCA transducers can produce spatial resolution similar to confocal transducers and steering is possible in the elevational and azimuthal planes. Optimal settings for number of elements, number of channels, maximum steering, and focal distance are suggested for VA clinical applications. Furthermore, an optimization for beam steering based on the channel assignment is proposed for balancing the contribution of the two waves in the steered focus.
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There are currently many types of protective materials for reinforced concrete structures and the influence of these materials in the chloride diffusion coefficient and water penetration still needs more research. The aim of this work is to analyze the contributions regarding the typical three surface concrete protection systems (coatings, linings and pore blockers) and discusses the results of three pore blockers (sodium silicate) tested in this work. To this end, certain tests were used: one involving permeability mechanism (low pressure-immersion absorption), one involving capillary water absorption, and the last, a migration test used to estimate the effective chloride diffusion coefficient in saturated condition. Results indicated reduction in chloride diffusion coefficients and capillary water absorption, therefore, restrictions to water penetration from external environmental. As a consequence, a reduction of the corrosion kinetics and a control of the chloride ingress are expected.
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Objective: To compare the efficacy of balance training associated with muscle strengthening or stretching, relative to no intervention, in the postural control of elderly women with osteoporosis. Design: A randomized, controlled trial. Subjects and interventions: Sample consisted of 50 women aged 65 years or older, with osteoporosis, randomized into one of three groups: strengthening group (n = 17) performed balance training with muscle strengthening; stretching group (n = 17) performed balance training with stretching; and control group (n = 16), no activities. Interventions lasted eight weeks, twice a week, 60 minutes a day. Main measures: Postural control was evaluated by the modified Clinical Test of Sensory Interaction for Balance (CTSIBm) and Limits of Stability Test. Strength was assessed by dynamometry and the shortening of the hamstrings by goniometry. Results: Relative to controls, participants in the strengthening group displayed significantly increased dorsiflexion strength and knee flexion strength, as well as centre of pressure velocity, directional control, and oscillation velocity (CTSIBm test). The stretching group had significantly improvements in hamstring length, knee flexion strength, centre of pressure velocity, and amplitude of movements. Relative to the stretching group, the strengthening group yielded better knee extension strength and directional control. Conclusion: The results suggest that both interventions are effective in improving postural control when compared to the control group, and the strengthening group was superior to the stretching group in knee extension strength and in directional control.
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This work studies the optimization and control of a styrene polymerization reactor. The proposed strategy deals with the case where, because of market conditions and equipment deterioration, the optimal operating point of the continuous reactor is modified significantly along the operation time and the control system has to search for this optimum point, besides keeping the reactor system stable at any possible point. The approach considered here consists of three layers: the Real Time Optimization (RTO), the Model Predictive Control (MPC) and a Target Calculation (TC) that coordinates the communication between the two other layers and guarantees the stability of the whole structure. The proposed algorithm is simulated with the phenomenological model of a styrene polymerization reactor, which has been widely used as a benchmark for process control. The complete optimization structure for the styrene process including disturbances rejection is developed. The simulation results show the robustness of the proposed strategy and the capability to deal with disturbances while the economic objective is optimized.
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This work studies the optimization and control of a styrene polymerization reactor. The proposed strategy deals with the case where, because of market conditions and equipment deterioration, the optimal operating point of the continuous reactor is modified significantly along the operation time and the control system has to search for this optimum point, besides keeping the reactor system stable at any possible point. The approach considered here consists of three layers: the Real Time Optimization (RTO), the Model Predictive Control (MPC) and a Target Calculation (TC) that coordinates the communication between the two other layers and guarantees the stability of the whole structure. The proposed algorithm is simulated with the phenomenological model of a styrene polymerization reactor, which has been widely used as a benchmark for process control. The complete optimization structure for the styrene process including disturbances rejection is developed. The simulation results show the robustness of the proposed strategy and the capability to deal with disturbances while the economic objective is optimized.
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This paper presents the new active absorption wave basin, named Hydrodynamic Calibrator (HC), constructed at the University of São Paulo (USP), in the Laboratory facilities of the Numerical Offshore Tank (TPN). The square (14 m 14 m) tank is able to generate and absorb waves from 0.5 Hz to 2.0 Hz, by means of 148 active hinged flap wave makers. An independent mechanical system drives each flap by means of a 1HP servo-motor and a ball-screw based transmission system. A customized ultrasonic wave probe is installed in each flap, and is responsible for measuring wave elevation in the flap. A complex automation architecture was implemented, with three Programmable Logic Computers (PLCs), and a low-level software is responsible for all the interlocks and maintenance functions of the tank. Furthermore, all the control algorithms for the generation and absorption are implemented using higher level software (MATLAB /Simulink block diagrams). These algorithms calculate the motions of the wave makers both to generate and absorb the required wave field by taking into account the layout of the flaps and the limits of wave generation. The experimental transfer function that relates the flap amplitude to the wave elevation amplitude is used for the calculation of the motion of each flap. This paper describes the main features of the tank, followed by a detailed presentation of the whole automation system. It includes the measuring devices, signal conditioning, PLC and network architecture, real-time and synchronizing software and motor control loop. Finally, a validation of the whole automation system is presented, by means of the experimental analysis of the transfer function of the waves generated and the calculation of all the delays introduced by the automation system.