Search results for "Aka"

A PC-based instrument for harmonics and interharmonics measurement in power supply systems

2004

Abstract Growing interest on power quality has led international working groups to define new standards for testing and measurement techniques to apply to power systems. Special attention has been paid to harmonic and interharmonic measurements. Here, the authors introduce a PC-based instrument capable of synchronising sampling frequency with fundamental frequency in order to perform on-line voltage or current distortion analysis. The instrument has been developed in accordance with currently available standards and international documents, IEC 61000-4-7 Ed. 2002, IEC 61000-4-30 Ed. 2003, Draft Guide IEEE P1159.1 Ed. 2003 and limits given by IEC 61000 Part. 3. A detailed description of the …

A robust fault detection design for uncertain Takagi-Sugeno models with unknown inputs and time-varying delays

2013

Abstract This paper investigates the problem of robust fault detection system design for a class of uncertain Takagi–Sugeno (T–S) models. The system under consideration is subject to unknown input and time-varying delay. The fault detection system is designed such that the unknown input is thoroughly decoupled from residual signals generated by the fault detection system. Furthermore, the residual signals show the maximum possible sensitivity to the faults and the minimum possible sensitivity to the external disturbances. The model matching approach is utilized to tackle the effects of parametric uncertainties in the model of the system. The design procedure is presented in terms of Linear …

Closed-loop bandwidth impact on MVSA for rotor broken bar diagnosis in IRFOC double squirrel cage induction motor drives

2013

This paper investigates the detectability of rotor broken bars in indirect rotor flux oriented control (IRFOC) for variable speed double cage induction motor drives, using vibration signature analysis techniques. The Impact of the closed loop control system cannot be neglected when the detection of rotor asymmetries in the machine is based on the signature analysis of electrical or mechanical variables. Therefore, the investigation of rotor fault components for different bandwidths of closed-loop regulators is necessary to evaluate its relevance in the above listed variables. This paper investigates the impact of the control system on relevance of the fault components computed from axial an…

Estimating the environmental and resource costs of leakage in water distribution systems: A shadow price approach.

2016

Water scarcity is one of the main problems faced by many regions in the XXIst century. In this context, the need to reduce leakages from water distribution systems has gained almost universal acceptance. The concept of sustainable economic level of leakage (SELL) has been proposed to internalize the environmental and resource costs within economic level of leakage calculations. However, because these costs are not set by the market, they have not often been calculated. In this paper, the directional-distance function was used to estimate the shadow price of leakages as a proxy of their environmental and resource costs. This is a pioneering approach to the economic valuation of leakage exter…

Co-digestion of energy crops and industrial confectionery by-products with cow manure: batch-scale and farm-scale evaluation.

2002

The possible co-digestion of energy crops and industrial confectionery by-products with cow manure was evaluated firstly, through long-term batch experiments and secondly, in a farm-scale digester. In batch assays, digestion with mesophilically digested cow manure as inoculum resulted in specific methane yields (m3 kg−1 VSadded waste) of 0.35 for grass hay (particle size <1.0 cm); 0.26 for oats (0.5 cm) and 0.21 for clover (2.0 cm) harvested at vegetative stage and 0.14 (2.0 cm) for clover harvested at flowering stage. Specific methane yields (m3 kg−1 VSadded waste) for confectionery by-products were 0.37 for chocolate, 0.39 for black candy and 0.32 for confectionery raw material. Ou…

Delayed chronic intracranial subdural hematoma complicating resection of a tanycytic thoracic ependymoma

2015

Background To demonstrate that the diagnosis of an intracranial subdural hematoma should be considered for patients presenting with acute or delayed symptoms of intracranial pathology following resection of a spinal tumor. Case description We present a case of a 57-year-old woman found to have a chronic subdural hematoma 1 month following resection of a thoracic extramedullary ependymoma. Evacuation of the hematoma through a burr hole relieved the presenting symptoms and signs. Resolution of the hematoma was confirmed with a computed tomography (CT) scan. Conclusion Headache and other symptoms not referable to spinal pathology should be regarded as a warning sign of an intracranial subdural…

Book review: Isohookana-Asunmaa, Tytti: Pieni tarina csángóista [O scurtă poveste despre ceangăi]. Ranua: Mäntykustannus

2012

SETUP OF VIRTUAL EXPERIMENTS AND CRITICAL ANALYSIS OF CONVENTIONAL THERMOECONOMIC DIAGNOSIS OF MULTIPLE FAULTS IN AIR-CONDENSED ROOFTOP SYSTEMS

2012

The diagnosis of soft faults in vapor compression cooling systems is a crucial activity, since malfunctions may provoke heavy degradation in plant performance and increase the power consumption for space cooling. Among the various Faults Detection and Diagnosis techniques developed over the last two decades, thermoeconomic diagnosis has been playing only a marginal role due to the difficulties encountered when applying the conventional thermoeconomic approaches to vapor compression refrigeration plants. In this paper a critical analysis on capabilities and limits of thermoeconomic diagnosis of refrigeration systems is proposed. The reference plant assumed for this study is a 116 kWc air-con…

ORIENTE E OCCIDENTE ALL'EXPO OSAKA 1970

2013

The writer remarks the technological innovation and contamination developed at the first World’s Fair held in Asia. He analyzes issues and methods of the master plan for the Osaka EXPO ’70, through a critical reading of Pavillon Plaza and Festival Plaza designed by Kenzo Tange and Arata Isozaki the emblematic covered area, facing the central EXPO square, reminds the utopia of the 60th architecture.

Oriente en la Exposición Universal de Osaka 1970

2016

La Exposicion Universal de Osaka en 1970 se propone como posible modelo de una nueva ciudad, en la cual los elementos efimeros tienden a estarmucho más presentes que la arquitectura misma, la cual se limita a definir el esqueleto del sistema constrùctivo. El tema propuesto pretende evidenciar un nuevo acercamiento a las consecuencias de la ideologia del progreso de la civilisación y la tecnologia con referencia a la Segunda Guerra Mundial como ejemplo destructivo del knowhow cientifico.