Optimising the feedback loop of a millimetre-wave absolute photoacoustic power meter using H-infinity control synthesis

An H-infinity control strategy has been developed for the design of controllers used in feedback controlled electrical substitution measurements (FCESM). The methodology has the potential to provide substantial improvements in both response time and resolution of a millimetre-wave absolute photoacoustic power meter.

Evaluation of Ohmic Instrument Company model UPM-30 ultrasound power meter /

Mode of access: Internet.

Operator's, organizational, direct support, general support, and depot maintenance manual (including repair parts) : power meter (Hewlett-Packard model 432A) (4931-436-4883), thermistor mount (Hewlett-Packard model 478A) (6625-866-1955).

Includes indexes.

Operator's, organizational, direct support, general support, and depot maintenance manual : standing-wave-ratio power meter ME-165/G (NSN 6625-00-682-4464).

Includes index.

A redistricting problem applied to meter reading in power distribution networks

The capacitated redistricting problem (CRP) has the objective to redefine, under a given criterion, an initial set of districts of an urban area represented by a geographic network. Each node in the network has different types of demands and each district has a limited capacity. Real-world applications consider more than one criteria in the design of the districts, leading to a multicriteria CRP (MCRP). Examples are found in political districting, sales design, street sweeping, garbage collection and mail delivery. This work addresses the MCRP applied to power meter reading and two criteria are considered: compactness and homogeneity of districts. The proposed solution framework is based on a greedy randomized adaptive search procedure and multicriteria scalarization techniques to approximate the Pareto frontier. The computational experiments show the effectiveness of the method for a set of randomly generated networks and for a real-world network extracted from the city of São Paulo. © 2013 Elsevier Ltd.

Analyzing track sprint cyclists' performances using position-specific maximal-torque and power-cadence relationships

Previous studies have demonstrated the importance of maximal Torque-Cadence (T-C) and Power-Cadence (P-C) relationships, for the performances of world class track sprint cyclists. If these relationships are affected by the function of the lower limb muscles, the ability of cyclists to generate torque and power at a given cadence may vary depending on their riding position. During sprint events (individual and team sprints and Keirin), cyclists alternate between standing and seated positions. The T-C and P-C relationships may change with the position adopted by the cyclists. PURPOSE: The aim of this study was to evaluate the necessity to define position specific maximal T-C and P-C relationships. METHODS: Eight junior elite track cyclists from the National Talent Identification squad undertook two inertial-load tests that consisted of four all-out sprints each. One test was undertaken at the velodrome in a standing position on a carbon fibre track bike, and the other test was completed in a seated position on an air-braked stationary ergometer. A calibrated SRM power meter interfaced to a custom instrumentation package was used for all mechanical measurements. Maximal T-C and P-C relationships were analysed to calculate maximal Torque (T0), maximal Power (Pmax) and optimal pedalling cadence (PCopt). RESULTS: All individual T-C and P-C relationships obtained for both body positions were fitted by linear regressions (r2=0.95 ± 0.02) and second order polynomials (r2=0.96 ± 0.01), respectively. T0 was higher (209 ± 2.2N.m vs. 177.0 ± 3.9N.m, p<0.05), PCopt was lower (112.5 ± 11.4rpm vs. 120.1 ± 6.7rpm, p<0.05), and Pmax was higher (1261 ± 235W vs. 1076 ± 183W, p<0.05) in standing position compared to seated position. CONCLUSION: Analysis of track sprint cyclists’ performances can be improved by the determination of position-specific maximal T-C and P-C relationships .

Power quality, smart meters and additional information from different power terms

This paper shows how the detailed examination of active and nonactive power components may produce new information for modern smart meters. For this purpose, a prototype of electronic power meter has been implemented and applied to the evaluation of the Conservative Power Theory (CPT). Considering five sorts of loads, under four different operating conditions, the experimental results indicate that the CPT is able to provide a good methodology for load characterization, which could possibly benefits consumers and power utilities in several different ways. The results also show that depending on the situation, the analysis of nonactive power terms may be more important than the observation of traditional power quality indices, such as total harmonic distortion, unbalance factors or the fundamental positive sequence power factor.

Load analyser using conservative power theory

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural and photoelectrical characterization of hot wall deposited CuInSe2 thin films and the fabrication of CuInSe2 based solar cells

Films of CuInSe2 were deposited onto glass substrates by a hot wall deposition method using bulk CuInSe2 as a source material. All the deposited CuInSe2 films were found to be polycrystalline in nature exhibiting the chalcopyrite structure with the crystallite orientation along (101),(112),(103),(211),(220),(312) and (400) directions. The photocurrent was found to increase with increase in film thickness and also with increase of light intensity. Photocurrent spectra show a peak related to the band-to-band transition. The spectral response of CuInSe2 thin films was studied by allowing the radiation to pass through a series of interference filters in the wavelength range 700-1200 rim. Films of higher thickness exhibited higher photosensitivity while low thickness films exhibited moderate photosensitivity. CuInSe2-based Solar cells with different types of buffer layers such as US, Cdse, CuInSe2 and CdSe0.7Te0.3 were fabricated. The current and voltage were measured using an optical power meter and an electrometer respectively. The fabricated solar cells were illuminated using 100 mW/cm(2) white light under AM1 conditions. (C) 2006 Elsevier Inc. All rights reserved.

Narrow-channel-spacing 32-channel arrayed-waveguide-grating multiplexer with an innovative alignment method

A 32-channel 50-GHz spaced arrayed-waveguide grating with our innovative configuration has been designed and fabricated. The performance of the device has been fully tested by using a tunable laser light source, optical power meter, and polarization controller. The insertion loss (IS) of the device is 4.2 similar to 7.4 dB. The crosstalk is about -28 clB. The IS uniformity is less than 3.2 dB. With our configuration, the performance of the device has been enhanced effectively and the difficulty in alignment process has been decreased obviously. (c) 2005 Society of Photo-Optical Instrumentation Engineers.

Low-cost Process monitoring for polymer extrusion

Polymer extrusion is regarded as an energy-intensive production process, and the real-time monitoring of both energy consumption and melt quality has become necessary to meet new carbon regulations and survive in the highly competitive plastics market. The use of a power meter is a simple and easy way to monitor energy, but the cost can sometimes be high. On the other hand, viscosity is regarded as one of the key indicators of melt quality in the polymer extrusion process. Unfortunately, viscosity cannot be measured directly using current sensory technology. The employment of on-line, in-line or off-line rheometers is sometimes useful, but these instruments either involve signal delay or cause flow restrictions to the extrusion process, which is obviously not suitable for real-time monitoring and control in practice. In this paper, simple and accurate real-time energy monitoring methods are developed. This is achieved by looking inside the controller, and using control variables to calculate the power consumption. For viscosity monitoring, a ‘soft-sensor’ approach based on an RBF neural network model is developed. The model is obtained through a two-stage selection and differential evolution, enabling compact and accurate solutions for viscosity monitoring. The proposed monitoring methods were tested and validated on a Killion KTS-100 extruder, and the experimental results show high accuracy compared with traditional monitoring approaches.

Produção Sustentável em BT- Análise de Características de Contadores Inteligentes

A crescente necessidade de reduzir a dependência energética e a emissão de gases de efeito de estufa levou à adoção de uma série de políticas a nível europeu com vista a aumentar a eficiência energética e nível de controlo de equipamentos, reduzir o consumo e aumentar a percentagem de energia produzida a partir de fontes renováveis. Estas medidas levaram ao desenvolvimento de duas situações críticas para o setor elétrico: a substituição das cargas lineares tradicionais, pouco eficientes, por cargas não-lineares mais eficientes e o aparecimento da produção distribuída de energia a partir de fontes renováveis. Embora apresentem vantagens bem documentadas, ambas as situações podem afetar negativamente a qualidade de energia elétrica na rede de distribuição, principalmente na rede de baixa tensão onde é feita a ligação com a maior parte dos clientes e onde se encontram as cargas não-lineares e a ligação às fontes de energia descentralizadas. Isto significa que a monitorização da qualidade de energia tem, atualmente, uma importância acrescida devido aos custos relacionados com perdas inerentes à falta de qualidade de energia elétrica na rede e à necessidade de verificar que determinados parâmetros relacionados com a qualidade de energia elétrica se encontram dentro dos limites previstos nas normas e nos contratos com clientes de forma a evitar disputas ou reclamações. Neste sentido, a rede de distribuição tem vindo a sofrer alterações a nível das subestações e dos postos de transformação que visam aumentar a visibilidade da qualidade de energia na rede em tempo real. No entanto, estas medidas só permitem monitorizar a qualidade de energia até aos postos de transformação de média para baixa tensão, não revelando o estado real da qualidade de energia nos pontos de entrega ao cliente. A monitorização nestes pontos é feita periodicamente e não em tempo real, ficando aquém do necessário para assegurar a deteção correta de problemas de qualidade de energia no lado do consumidor. De facto, a metodologia de monitorização utilizada atualmente envolve o envio de técnicos ao local onde surgiu uma reclamação ou a um ponto de medição previsto para instalar um analisador de energia que permanece na instalação durante um determinado período de tempo. Este tipo de monitorização à posteriori impossibilita desde logo a deteção do problema de qualidade de energia que levou à reclamação, caso não se trate de um problema contínuo. Na melhor situação, o aparelho poderá detetar uma réplica do evento, mas a larga percentagem anomalias ficam fora deste processo por serem extemporâneas. De facto, para detetar o evento que deu origem ao problema é necessário monitorizar permanentemente a qualidade de energia. No entanto este método de monitorização implica a instalação permanente de equipamentos e não é viável do ponto de vista das empresas de distribuição de energia já que os equipamentos têm custos demasiado elevados e implicam a necessidade de espaços maiores nos pontos de entrega para conter os equipamentos e o contador elétrico. Uma alternativa possível que pode tornar viável a monitorização permanente da qualidade de energia consiste na introdução de uma funcionalidade de monitorização nos contadores de energia de determinados pontos da rede de distribuição. Os contadores são obrigatórios em todas as instalações ligadas à rede, para efeitos de faturação. Tradicionalmente estes contadores são eletromecânicos e recentemente começaram a ser substituídos por contadores inteligentes (smart meters), de natureza eletrónica, que para além de fazer a contagem de energia permitem a recolha de informação sobre outros parâmetros e aplicação de uma serie de funcionalidades pelo operador de rede de distribuição devido às suas capacidades de comunicação. A reutilização deste equipamento com finalidade de analisar a qualidade da energia junto dos pontos de entrega surge assim como uma forma privilegiada dado que se trata essencialmente de explorar algumas das suas características adicionais. Este trabalho tem como objetivo analisar a possibilidade descrita de monitorizar a qualidade de energia elétrica de forma permanente no ponto de entrega ao cliente através da utilização do contador elétrico do mesmo e elaborar um conjunto de requisitos para o contador tendo em conta a normalização aplicável, as características dos equipamentos utilizados atualmente pelo operador de rede e as necessidades do sistema elétrico relativamente à monitorização de qualidade de energia.

Photoacoustic effect: Some applications in laser technology

The discovery of the Photoacoustic (PA) effect was a remarkable achievement and was relegated to the scientific footnotes of the nineteenth century. However, after the advent of lasers and sophisticated electronics this effect was rediscovered and it has established itself as an important research and analytical tool in numerous areas, including physics, chemistry, biology and medicine. Quite recently, this phenomenon has made its impact in the field of laser technology for applications such as the developments of highly efficient active media for lasers, high quality optics and sensitive laser power monitoring devices. This thesis presents the work carried out by the author in this field during the past few years at the Department of Physics in Cochin University of Science and Technology. The studies discussed here are mostly based on the development of a sensitive PA laser power meter and its various applications using different laser systems available in the laboratory. This includes the development of a current regulated CW C0 laser and its application in material processing. The thesis contains seven chapters which by and large are self contained with separate abstracts and references. The first chapter which is divided into two parts presents an introduction to the PA effect and its present status. Part A reviews the basic theory of laser and gives a sum mary of various lasers and their applications. Part B presents a brief description of PA effect and its suitability as a spectroscopic tool followed by its applications to various branches of science and technology.

NodePM: A Remote Monitoring Alert System for Energy Consumption Using Probabilistic Techniques

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Skin Penetration Time-Profiles for Continuous 810nm and Superpulsed 904nm Lasers in a Rat Model

Objective: The purpose of this study was to investigate the rat skin penetration abilities of two commercially available low-level laser therapy (LLLT) devices during 150 sec of irradiation. Background data: Effective LLLT irradiation typically lasts from 20 sec up to a few minutes, but the LLLT time-profiles for skin penetration of light energy have not yet been investigated. Materials and methods: Sixty-two skin flaps overlaying rat's gastrocnemius muscles were harvested and immediately irradiated with LLLT devices. Irradiation was performed either with a 810 nm, 200mW continuous wave laser, or with a 904 nm, 60mW superpulsed laser, and the amount of penetrating light energy was measured by an optical power meter and registered at seven time points (range, 1-150 sec). Results: With the continuous wave 810nm laser probe in skin contact, the amount of penetrating light energy was stable at similar to 20% (SEM +/- 0.6) of the initial optical output during 150 sec irradiation. However, irradiation with the superpulsed 904 nm, 60mW laser showed a linear increase in penetrating energy from 38% (SEM +/- 1.4) to 58% (SEM +/- 3.5) during 150 sec of exposure. The skin penetration abilities were significantly different (p < 0.01) between the two lasers at all measured time points. Conclusions: LLLT irradiation through rat skin leaves sufficient subdermal light energy to influence pathological processes and tissue repair. The finding that superpulsed 904nm LLLT light energy penetrates 2-3 easier through the rat skin barrier than 810nm continuous wave LLLT, corresponds well with results of LLLT dose analyses in systematic reviews of LLLT in musculoskeletal disorders. This may explain why the differentiation between these laser types has been needed in the clinical dosage recommendations of World Association for Laser Therapy.