158 research outputs found
O percurso histórico da cultura drag: uma análise da cena queer carioca
Investiga aspectos globais da construção da cultura drag, partindo de contextos em que o ato de se montar representava apenas uma necessidade cênica; até o atual contexto; para, num momento posterior, tecer uma análise da atual cena drag carioca, mapeando as diferenças e semelhanças entre duas gerações de drag queens, representadas pelos coletivos Turma OK e Drags-se. São observados também aspectos históricos da cena drag local, bem como as influências, concepções artísticas e posições políticas das artistas abordadas para, dessa maneira, determinar as razões do “corte geracional” observado entre as neo drags, grupo de artistas surgido recentemente, e a geração anterior a elas
Pluralism in economics : from epistemology to hermeneutics
The objective of this paper is to bring elements from the philosophical movement ofhermeneutics and pragmatism to the discussion on methodology in economics, with aspecific concern on the theory of truth. Our aim is to present the concept of thehermeneutic space, developed by the philosopher Richard Rorty, as a rational justificationfor pluralism in economics. We consider the hermeneutic space an interesting conceptwhich should allow us to overcome the void left by the incapacity of epistemologicaltheories to explain the evolution of sciences. It defends the idea that our culture, values andways of interpreting things are what build the sciences, not any closed epistemologicalmethod. In this sense, pluralism is nothing more than letting the hermeneutic space work,without epistemological barriers, and understanding that this is desirable for the futuredevelopment of economics as a science. This approach differs from all othermethodological justifications for pluralism because it does not rely on any epistemologicalmethod, but assumes that the hermeneutic space can entirely fulfill the gap created by them
AVALIAÇÃO DE RISCO FÍSICO: EXPOSIÇÃO OCUPACIONAL AOS NÍVEIS DE PRESSÃO SONORA EM UMA INDÚSTRIA DE TRANSFORMAÇÃO
Dentre as formas de energia caracterizada como riscos físicos, exemplo o ruído, pode ser considerado como um dos principais agentes causadores de doenças ocupacionais. Objetivou-se avaliar a exposição dos operadores de máquinas de uma indústria de transformação, aos níveis de pressão sonora para comparação dos níveis estabelecidos pela legislação brasileira e determinação da dose diária que os operadores estão expostos. O estudo foi desenvolvido em uma serraria que realiza o desdobro de madeira, localizada no Estado de São Paulo. Os níveis de ruído foram coletados durante toda a jornada diária de trabalho por meio de um dosímetro de uso pessoal. Os resultados evidenciaram que dentre os postos de trabalho ponderados no estudo, somente um posto não possui nível de ruído acima do estabelecido pela legislação vigente. Logo, torna-se imperativo a utilização de equipamentos de proteção individual e de equipamentos de proteção coletiva, ademais, recomenda-se o enclausuramento acústico das máquinas geradoras de ruído acima de 115 dBA
Technical-Economic Analysis of Grapple Saw: A Stochastic Approach
The processing of Eucalyptus logs is a stage that follows the full tree system in mechanized forest harvesting, commonly performed by grapple saw. Therefore, this activity presents some associated uncertainties, especially regarding technical and silvicultural factors that can affect productivity and production costs. To get around this problem, Monte Carlo simulation can be applied, or rather a technique that allows to measure the probabilities of values from factors that are under conditions of uncertainties, to which probability distributions are attributed. The objective of this study was to apply the Monte Carlo method for determining the probabilistic technical-economical coefficients of log processing using two different grapple saw models. Field data were obtained from an area of forest planted with Eucalyptus, located in the State of São Paulo, Brazil. For the technical analysis, the time study protocol was applied by the method of continuous reading of the operational cycle elements, which resulted in production. As for the estimated cost of programmed hour, the applied methods were recommended by the Food and Agriculture Organization of the United Nations. The incorporation of the uncertainties was carried out by applying the Monte Carlo simulation method, by which 100,000 random values were generated. The results showed that the crane empty movement is the operational element that most impacts the total time for processing the logs; the variables that most influence the productivity are specific to each grapple saw model; the difference of USD 0.04 m3 in production costs was observed between processors with gripping area of 0.58 m2 and 0.85 m2. The Monte Carlo method proved to be an applicable tool for mechanized wood harvesting for presenting a range of probability of occurrences for the operational elements and for the production cost
The Impact of Felling Method, Bunch Size, Slope Degree and Skidding Area on Productivity and Costs of Skidding in a Eucalyptus Plantation
Grapple skidder is a machine designed for the extraction of tree bunches after felling. Several factors influence its technical performance and costs such as terrain slope, operator experience time, machine type, and the size of tree bunches for each operating cycle, among others. Thus, it becomes necessary to weigh the variables that most influence the productivity and costs of the grapple skidder. So, the main objective was evaluated according to the influence of bunch size using two feller bunchers with distinct technical characteristics, two slope classes and two skidding areas on the productivity and machine production cost in a Eucalyptus plantation. For the analysis of the productivity, the study of time and method was applied and the scheduled machine cost per hour was based on the Food and Agriculture Organization of the United Nations methods. When analyzing the results, it was found that the operational elements moving without load (MWoL) and moving with load (MWL) were the ones that spend the most time in the operational cycle of the grapple skidder. Among the cost components, monetary expenditure on fuel and operator labor were the most influential in the scheduled machine cost per hour. In conclusion, the tree bunches and slope class influenced the productivity and, consequently, the cost of the skidding operation
Exposure to Occupational Noise: Machine Operators of Full Tree System in Brazil
Physical agent noise can be considered one of the main disturbances that compromise the
occupational health of self-propelled forest machine operators. We evaluated whether
occupational noise levels emitted by self-propelled forest machines employed in the full tree
system are in accordance with both the National Institute for Occupational Safety and Health
and ISO 1999:2013 standards, while also proposing mitigating measures aimed at protecting
the operators hearing. Seventeen operators, who performed wood harvesting operations in
Eucalyptus forests in Brazil, were analyzed. Noise levels were collected in a daily shift of eight
hours as recommended by the Acoustics – Determination of occupational noise exposure -
Engineering method for full-day measurements (ISO 9612:2009). The standards adopted for
the evaluation were the exposure action value of 80 dBA and the exposure limit of 85 dBA
based on the National Institute for Occupational Safety and Health – NIOSH and on Acoustics
– Estimation of noise-induced hearing loss (ISO 1999:2013) Directive 2003/10/EC. The
operators were arranged in homogeneous groups according to the Acoustics recommendation
– Determination of occupational noise exposure – Engineering method for full-day
measurements (ISO 9612:2009), classified by the operations of felling, skidding of tree bundles
and bucking. The results showed that 17 self-propelled forest machines exceeded the exposure
action value of 80 dBA, of which 10 machines exceeded the exposure limit of 85 dBA. It was
concluded that the levels of occupational noise emitted by self-propelled forest machines used
in the full tree system are higher than those recommended by both standards, National Institute
for Occupational Safety and Health and ISO 1999:2013. Therefore, the allocation of selfpropelled
forest machines to homogeneous groups allows inferring mitigation actions that
protect operators’ hearing. The correct use of hearing protectors during the daily workday
provides hearing protection for operators in mechanized wood harvesting. Adoption of actions
such as maintenance of cabin seals and mechanical components, breaks for fatigue relief,
reduction of daily working hours and rotation of operators in different self-propelled forest
machines can mitigate the damage to the occupational health of operators
ECONOMIC VALUATION OF THE Eucalyptus urograndis PRODUCTION IN TWO TYPES OF CONTAINERS
The systematic treatment of uncertainties associated with forest production processes allows the establishment of technical and managerial strategies to mitigate the risk inherent in the application of capital demanded in the production of cuttings. Therefore, the aim of this research was to ascertain the unit risk to produce Eucalyptus cuttings using the Monte Carlo simulation method. Based on the estimate of the production cost of Eucalyptus cuttings and in the expected revenues of six productive systems, characterized as forestry investment projects, it was possible to construct cash flows followed by the metrics used for the decision of mutually exclusive investment projects. The incorporation of risk analysis had as propositions the uncertainties associated with the productive factors, in which probability distributions were attributed. Then, pseudorandom numbers were generated by the Monte Carlo simulation method, with the purpose of measuring the stochastic economic values and the probabilities of occurrences for the project metrics. The stochastic results showed that the probability of economic viability for the analyzed conditions is null. The most critical stochastic variables of forestry projects are investments and the cycle production of cuttings.
Design and Performance Evaluation of SMC-Based DC–DC Converters for Microgrid Applications
In recent times, DC microgrids (MGs) have received significant attention due to environmental concerns and the demand for clean energies. Energy storage systems (ESSs) and photovoltaic (PV) systems are parts of DC MGs. This paper expands on the modeling and control of non-isolated, non-inverting four-switch buck-boost (FSBB) synchronous converters, which interface with a wide range of low-power electronic appliances. The proposed power converter can work efficiently both independently and in DC MGs. The charging and discharging of the battery are analyzed using the FSBB converter at a steady state in continuous conduction mode (CCM). A boost converter is connected to a PV system, which is then connected in parallel to the battery to provide voltages at the DC bus. Finally, another FSBB converter is connected to a resistive load that successfully performs the boost-and-buck operation with smooth transitions. Since these power converters possess uncertainties and non-linearities, it is not suitable to design linear controllers for these systems. Therefore, the controlling mechanism for these converters’ operation is based on the sliding mode control (SMC). In this study, various macro-level interests were achieved using SMC. The MATLAB Simulink results successfully prove the precise reference tracking and robust stability in different operating modes of DC–DC converters in a MG structure.© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed
GRAPPLE SAW’S OPERATING CONDITIONS INFLUENCE ON THE PRODUCTIVITY AND COST OF PROCESSING FELLED TREES
In the full-tree system, one of the self-propelled forest machines used is the grapple saw, which uses mechanical force to delimbing and crosscutting stems, commonly in processing yards or on the sides of forest roads. Thus, several factors can influence the machine's effective productivity, and consequently, the production costs. Hence, the objective was to analyze the influence of the slope of the land on the productivity and production costs of the grapple saw under different operational conditions. The study was carried out in a forested area, in which there were clonal forests of Eucalyptus urograndis. The processing felled trees operation was performed with a grapple saw capable of accumulating and cutting the 0.85 m² tree bundles in two operating conditions. For the production forecast, the time study was applied, associating it to the volume of drawn wood and the effective work time, accordingly, it was possible to estimate the production cost of the grapple saw. The results allowed to conclude that the effective hourly productivity and the production cost of the log tracing are associated with the slope of the land
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