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101.
Paulo Augusto Cunha Libanio 《国际水》2013,38(3):513-533
This article examines the use of output-based aid and payment for environmental services to reduce water pollution in Brazil. Two nationwide initiatives are reviewed. First, the output-based aid concept of the River Basin Clean-up Programme (PRODES) to tackle the problem of sanitation deficit in urban areas is presented. Second, the payment for environmental services scheme supported by Brazil’s National Water Agency (ANA) through the Water Producer Programme to promote water conservation on rural properties is discussed. Both programmes are evaluated not only as financing mechanisms for water conservation but also as strategies for implementing Brazil’s water policy. 相似文献
102.
Decision support system to divide a large network into suitable District Metered Areas 总被引:2,自引:0,他引:2
This paper presents a new approach to divide large Water Distribution Networks (WDN) into suitable District Metered Areas (DMAs). It uses a hydraulic simulator and two operational models to identify the optimal number of DMAs, their entry points and boundary valves, and the network reinforcement/replacement needs throughout the project plan. The first model divides the WDN into suitable DMAs based on graph theory concepts and some user-defined criteria. The second model uses a simulated annealing algorithm to identify the optimal number and location of entry points and boundary valves, and the pipes reinforcement/replacement, necessary to meet the velocity and pressure requirements. The objective function is the difference between the economic benefits in terms of water loss reduction (arising from the average pressure reduction) and the cost of implementing the DMAs. To illustrate the proposed methodology, the results from a hypothetical case study are presented and discussed. 相似文献
103.
Jun Okamoto Jr. Valdir Grassi Jr. Paulo Faria Santos Amaral Benedito Geraldo Miglio Pinto Daniel Pipa Gustavo Pinto Pires Marcus Vinicius Maciel Martins 《Journal of Intelligent and Robotic Systems》2012,66(1-2):23-35
Inspection for corrosion of gas storage spheres at the welding seam lines must be done periodically. Until now this inspection is being done manually and has a high cost associated to it and a high risk of inspection personel injuries. The Brazilian Petroleum Company, Petrobras, is seeking cost reduction and personel safety by the use of autonomous robot technology. This paper presents the development of a robot capable of autonomously follow a welding line and transporting corrosion measurement sensors. The robot uses a pair of sensors each composed of a laser source and a video camera that allows the estimation of the center of the welding line. The mechanical robot uses four magnetic wheels to adhere to the sphere’s surface and was constructed in a way that always three wheels are in contact with the sphere’s metallic surface which guarantees enough magnetic atraction to hold the robot in the sphere’s surface all the time. Additionally, an independently actuated table for attaching the corrosion inspection sensors was included for small position corrections. Tests were conducted at the laboratory and in a real sphere showing the validity of the proposed approach and implementation. 相似文献
104.
Paulo Leit?o J. Marco Mendes Axel Bepperling Daniel Cachapa Armando W. Colombo Francisco Restivo 《Journal of Intelligent Manufacturing》2012,23(6):2551-2563
Engineering frameworks are currently required to support the easy, low-cost, modular and integrated development of manufacturing systems addressing the emergent requirements of re-configurability, responsiveness and robustness. This paper discusses the integration of 2D/3D digital software tools with Petri net based service-oriented frameworks to allow the design, configuration, analysis, validation, simulation, monitoring and control of manufacturing systems in a virtual environment and its posterior smooth migration into the real ??physical?? environment. An experimental case study was implemented to validate the proposed concepts, using the Continuum platform to design, compose, analyze, validate and simulate the Petri nets based service-oriented manufacturing control system, and the Delmia AutomationTM software suite to support the rapid prototyping and the easy simulation of the designed control solution. The experimental results prove several aspects of the proposed approach, notably the smooth migration between the design and the operation phases, one of the main objectives of the work. 相似文献
105.
Arranging office space into a single open room offers advantages in terms of easy exchange of information and interaction among coworkers, but reduces privacy and acoustic comfort. Thus, the purpose of this work was to evaluate the acoustic quality of a real open-plan office and to propose changes in the room to improve the acoustic conditioning of this office. The computational model of the office under study was calibrated based on RT and STI measurements. Predictions were made of the RT and STI, which generated the radius of distraction r(D), and the rate of spatial decay of sound pressure levels per distance doubling DL(2) in the real conditions of the office and after modifications of the room. The insertion of dividers between work stations and an increase in the ceiling's sound absorption improved the acoustic conditions in the office under study. 相似文献
106.
A New Distribution System Reconfiguration Approach Using Optimum Power Flow and Sensitivity Analysis for Loss Reduction 总被引:2,自引:0,他引:2
Gomes F.V. Carneiro S. Jr. Pereira J.L.R. Vinagre M.P. Garcia P.A.N. De Araujo L.R. 《Power Systems, IEEE Transactions on》2006,21(4):1616-1623
This paper presents a new approach for distribution system reconfiguration (DSR) based on optimum power flow (OPF) in which the branch statuses (open/close) are represented by continuous functions. In the proposed approach, all branches are initially considered closed, and from the OPF results, a heuristic technique is used to determine the next loop to be broken by opening one switch. Then the list of switches that are candidates to be opened is updated, and the above process is repeated until all loops are broken, making the distribution system radial. This paper includes results and comparisons on test systems utilized in three classical papers published in the technical literature, as well as in a previous paper by the authors. Results obtained on a real large-scale distribution system are also presented 相似文献
107.
Italo Odone Mazali Luiz Carlos Barbosa Oswaldo Luiz Alves 《Journal of Materials Science》2004,39(6):1987-1995
In the present work we describe the synthesis, spectroscopy, thermal and chemical durability properties of the vitreous system Li2O-Nb2O5-CaO-P2O5 (LNCP). Investigations of the short-range order by Fourier transform infrared, Raman, UV-VIS and 31P MAS-NMR spectroscopies suggest that the network former glass consists of Nb octahedra linked to pyro/orthophosphate units through Nb—O—P bonds. The presence of modifier cations (Li+ and Ca2+) promotes depolymerization of the P—O—P chains, yielding pyro/orthophosphate units. The presence of this kind of structure accounts for the improvement of the chemical durability at low pH when the Nb content in the LNCP glass composition is high. The density and linear refractive indices of LNCP glasses increased linearly as the Nb2O5/P2O5 molar ratio increased, as a consequence of P2O5 substitution by Nb2O5 as the glassformer. The dependence of the glass transition temperature, the softening temperature and the crystallization temperature on the Nb2O5/P2O5 ratio exhibits the same behavior. On the other hand, the thermal expansion coefficient decreases with the increased Nb2O5/P2O5 ratio. 相似文献
108.
Celso M. F. Lapa Paulo A. B. de Sampaio Cludio M. N. A. Pereira 《Nuclear Engineering and Design》2004,229(2-3):205-212
Reduced scale experiments are often employed in engineering because they are much cheaper than real scale testing. Unfortunately, though, it is difficult to design a thermal-hydraulic circuit or equipment in reduced scale capable of reproducing, both accurately and simultaneously, all the physical phenomena that occur in real scale and operating conditions. This paper presents a methodology to designing thermal-hydraulic experiments in reduced scale based on setting up a constrained optimization problem that is solved using genetic algorithms (GAs). In order to demonstrate the application of the methodology proposed, we performed some investigations in the design of a heater aimed to simulate the transport of heat and momentum in the core of a pressurized water reactor (PWR) at 100% of nominal power and non-accident operating conditions. The results obtained show that the proposed methodology is a promising approach for designing reduced scale experiments. 相似文献
109.
The development and computational implementation, on a multibody dynamics environment, of a constitutive relation to model
bushing elements associated with mechanical joints used in the models of road and rail vehicles is presented here. These elements
are used to eliminate vibrations in vehicles, due to road irregularities, to allow small misalignment of axes, to reduce noise
from the transmission, or to decrease wear of the mechanical joints. Bushings are made of a special rubber, used generally
in energy dissipation, which presents a nonlinear viscoelastic relationship between the forces and moments and their corresponding
displacements and rotations. In the methodology proposed here a finite element model of the bushing is developed in the framework
of the finite element code ABAQUS to obtain the constitutive relations of displacement/rotation versus force/moment for different
loading cases. The bushing is modeled in a multibody code as a nonlinear restrain that relates the relative displacements
between the bodies connected with the joint reaction forces, and it is represented by a matrix constitutive relation. The
basic ingredients of the multibody model are the same vectors and points relations used to define kinematic constraints in
any multibody formulation. One particular, and relevant, characteristic of the formulation now presented is its ability to
represent standard kinematic joints, clearance, and bushing joints just by defining appropriate constitutive relations. Spherical,
revolution, cylindrical, and translational bushing joints are modeled, implemented, and demonstrated through the simulation
of two multibody models of a road vehicle, one with perfect kinematic joints for the suspension sub-systems, and other with
bushing joints. The tests conducted include an obstacle avoidance maneuver and a vehicle riding over bumps. It is shown that
the bushing models for vehicle multibody models proposed here are accurate and computationally efficient so that they can
be included in the vehicle models leading reliable simulations. 相似文献
110.