Line-pack management for producing electric power on peak periods

The distribution of natural gas is carried out by means of long ducts and intermediate compression stations to compensate the pressure drops due to friction. The natural gas compressors are usually driven by an electric motor or a gas turbine system, offering possibilities for energy management, one of these consisting in generating energy for use in-plant or to commercialize as independent power producer. It can be done by matching the natural gas demand, at the minimum pressure allowed in the reception point, and the storage capacity of the feed duct with the maximum compressor capacity, for storing the natural gas at the maximum permitted pressure. This allows the gas turbine to drive an electric generator during the time in which the decreasing pressure in duct is above the minimum acceptable by the sink unit. In this paper, a line-pack management analysis is done for an existing compression station considering its actual demand curve for determining the economic feasibility of maintaining the gas turbine system driver generating electricity in a peak and off-peak tariff structure. The potential of cost reduction from the point of view of energy resources (natural gas and electric costs) is also analyzed. (C) 2010 Elsevier Ltd. All rights reserved.

WEDGE - ferramenta on-line de gerenciamento, análise e otimização de processos

This article summarizes the implementation of an online process management, analysis, and optimization tool at Lwarcel Celulose e Papel, within the PIMS and MES philosophy, for process indicator implementation, understanding of variables, and their cause-effect relationship in the process, as well as the achievement of operational benchmarking. The process analysis, by means of statistical tools, allied to mathematical modeling algorithms used in Wedge, makes it possible to identify the relevant information for process and quality improvement with regard to efficiency, equipment maintenance, productivity, and uniformity of the end product quality, reduction of unwanted shutdowns, and quicker resolution of process problems.

A novel single-phase hpf hybrid rectifier suitable for front-end trolleybus systems

This paper proposal presents the development and the experimental analysis of a new single-phase hybrid rectifier structure with high power factor (PF) and low harmonic distortion of current (THDI), suitable for application in traction systems of electrical vehicles pulled by electrical motors (trolleybus), which are powered by urban distribution network. This front-end rectifier structure is capable of providing significant improvements in trolleybuses systems and in the urban distribution network costs, and efficiency. The proposed structure is composed by an ordinary single-phase diode rectifier with parallel connection of a switched converter. It is outlined that the switched converter is capable of composing the input line current waveform assuring high power factor (HPF) and low THDI, as well as ordinary front-end converter. However, the power rating of the switched converter is about 34% of the total output power, assuring robustness and reliability. Therefore, the proposed structure was named single-phase HPF hybrid rectifier. A prototype rated at 15kW was developed and analyzed in laboratory. It was found that the input line current harmonic spectrum is in accordance with the harmonic limits imposed by IEC61000-3-4. The principle of operation, the mathematical analysis, the PWM control strategy, and experimental results of a 15kW prototype are also presented in this paper. © 2009 IEEE.

Proposal of a hybrid rectifier structure with HPF and low THD suitable for front-end trolleybuses systems supplied by AC distribution networks

This paper presents the development and the experimental analysis of a new single-phase hybrid rectifier structure with high power factor (PF) and low harmonic distortion of current (THDI), suitable for application in traction systems of electrical vehicles pulled by electrical motors (trolleybus), which are powered by urban distribution network. This front-end rectifier structure is capable of providing significant improvements in trolleybuses systems and in the urban distribution network costs, and efficiency. The proposed structure is composed by an ordinary single-phase diode rectifier with parallel connection of a switched converter. It is outlined that the switched converter is capable of composing the input line current waveform assuring high power factor (HPF) and low THDI, as well as ordinary front-end converter. However, the power rating of the switched converter is about 34% of the total output power, assuring robustness and reliability. Therefore, the proposed structure was named single-phase HPF hybrid rectifier. A prototype rated at 15kW was developed and analyzed in laboratory. It was found that the input line current harmonic spectrum is in accordance with the harmonic limits imposed by IEC61000-3-4. The principle of operation, the mathematical analysis, the PWM control strategy, and experimental results are also presented in this paper. © 2009 IEEE.

Irrigation management in pruned coffee tree crop

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Failure of miniplate osteosynthesis for the management of atrophic mandibular fracture

Fractures of the severely atrophic (<10 mm) edentulous mandible are not common, and these fractures with a vertical height of 10 mm or less have long been recognized as being particularly problematic. Although there are advances in the treatment of the atrophic mandibular fracture, the treatment remains controversial. There are some options for treatment planning because of using small miniplates to large reconstruction plates. However, when the fixation method fails, it causes malunion, nonunion, and/or infection, and sometimes it has been associated with large bone defects. The authors describe a clinical report of a failed miniplate fixation for atrophic mandibular fracture management. The authors used a load-bearing reconstruction plate combined with autogenous bone graft from iliac crest for this retreatment. The authors show a follow-up of 6 months, with union of the fracture line and no complication postoperatively. © 2013 by Mutaz B. Habal, MD.

Gestão da informação no jornalismo on-line: estudo do portal Campo Grande News

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Improving logistics services through the technology used in fleet management

Outsourcing logistics has established itself in the area of the LSP (Logistics Service Provider), which offers a range of services to its customers. In this line, transportation is characterized as one of the most important services, and therefore efficient fleet management is essential for establishing a high level of customer service. With advances in technology and vehicle tracking systems, this approach of management has gained new possibilities for the improvement of logistics services. By studying the specific case of an LSP, this paper investigates the use of these technologies in the management of their business and services. The results indicate that the LSP seeks to increase its services and to streamline information in order to respond to customer needs in real time. It is also evident in this case under study that the combination of the technology available together with the fleet management system has become a distinguishing feature for this LSP, one which increases their skills and important information for both customers and business.