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This paper describes the need for technologies that improve analytical sensitivity to proteins to better define and monitor the progression from heath to disease over the course of an individual's life. These technologies have the potential to allow the early diagnosis of disease, and trigger treatments at the time when they have the greatest opportunity to be effective. We will describe a technology that we have developed for high sensitivity protein detection, namely, single molecule arrays (Simoa). Simoa is based on the capture of protein molecules on magnetic beads, labeling each protein with an enzyme, and counting of single enzyme labels on beads that are isolated in arrays of femtoliter wells. Simoa has enabled the detection of proteins at subfemtomolar concentrations in a variety of biological fluids. We describe the impact of higher sensitivity of proteins using Simoa on: less invasive testing; earlier detection of disease; providing biomarker baseline profiles for healthy individuals; testing of small sample volumes; monitoring of therapeutic efficacy; faster tests; and detection of proteins in complex samples. We also provide a perspective of how new technologies that allow the low-cost manufacture and miniaturization of Simoa could drive the next wave of analytical devices, including wearables. [ABSTRACT FROM AUTHOR]

The ITER plasma position reflectometry system will be used to estimate the distance between the position of the magnetic separatrix and the first wall at four predefined locations, complementing the magnetic diagnostics system. The antennas of the system studied in this paper are to be installed between the blanket shield modules of rows 3 and 4, on the high-field side of the tokamak. As the antennas and part of the corresponding waveguides will be directly exposed to the plasma, they will be subjected to high radiation doses from neutrons and gammas, which may cause irradiation-induced changes in the material properties and compromise the integrity of the components. In this paper, the Monte Carlo simulation code MCNP6 and the most up-to-date ITER reference neutronics model were used to estimate the thermal loads in the system. The results, complemented with a finite-element analysis performed with ANSYS Mechanical, show that the nuclear heat loads, combined with the thermal radiation coming from the plasma, translate into operation temperatures that reach 480 °C at the tips of the antennas, slightly above the maximum recommended temperature of operation of stainless steel for ITER in-vessel components under irradiation (450 °C). Further, thermal analyses and design iterations are therefore required to improve the thermal and mechanical behavior of the system. [ABSTRACT FROM AUTHOR]

The diagnostic machinery monitoring system presented in this paper coordinates the acquisition of vibration and speed estimates for an electric machine. It functions even when the machine is “off” or spinning down. This effectively turns the machine into its own mechanical network analyzer. Data from this system can be used to correlate electrical and mechanical data in order to distinguish a variety of pathologies in the machine and its mechanical mounts. The entire sensor system powers itself from surrounding magnetic fields, requiring no ohmic contact or special power wiring. The system presented in this paper presents a unique approach for fusing data from multiple sensors to create a coordinated picture of machine operation on a self-powered platform. [ABSTRACT FROM AUTHOR]

The reflectometry diagnostic for demonstration fusion reactor (DEMO) is envisaged to provide the electron density profile and to be used as a control diagnostic for the real-time vertical position controller. An initial conceptual study has been performed defining the position of the antennas and the routing of the waveguides. In the present design, the integration has been driven by the remote handling and blanket interfaces. To progress with the system integration, neutronics simulations were performed to assess the cooling requirements. This paper presents a nuclear and thermal analysis for the initial design of the reflectometry diagnostic for DEMO. The neutronics simulations were performed using the Monte Carlo simulation program MCNP6 and FENDL 2.1 cross sections, while ANSYS mechanical v18 was used to perform the thermal analysis. Simulation results show that the nuclear heat loads reach 8 W/cm3 at the surface of the diagnostics section. Without an active cooling system, the operating temperatures of the components under such heat loads would be well above the acceptable from the thermomechanical point of view. The thermal analysis here presented provides the temperature distribution in the components when subjected to neutron/gamma irradiation and thermal radiation from the plasma, after the implementation of a preliminary design of the active cooling system. The operation temperatures of the plasma-facing antennas, as well as the performance of the diagnostics system from the neutron shielding point of view, are analyzed and discussed in this paper. [ABSTRACT FROM AUTHOR]

It is common practice in the industry for electrical workers to be exposed to shock and arc blast and arc flash hazards as they perform routine maintenance and diagnostic testing on equipment enclosed in motor control centers (MCCs). This paper will illustrate the influence that various IEEE conferences, including the Electrical Safety Workshop, has had on changing the electrical safety culture related to equipment diagnostics. End users are now requesting manufacturers of low- and medium-voltage MCCs to develop or add features and functionality into their products that enhance the ability of electrical maintenance and operating personnel to conduct routine diagnostic and troubleshooting tasks without being directly exposed to energized electrical equipment. This paper will explore some of these features and provide some examples of routine maintenance and diagnostic tasks that can be performed while doing troubleshooting and diagnostic tasks on operating equipment without opening enclosure doors and exposing workers to the hazards associated with exposed energized equipment. [ABSTRACT FROM PUBLISHER]

ITER has many ports to install various diagnostics which view and measure various plasma parameters. One of the ports, the upper port #18 (UP18) is designed to integrate three tenant diagnostic systems: vacuum ultraviolet spectrometer, neutron activation system, and upper vertical neutron camera. The key design drivers for the port integration are requirements on neutron shielding and maintenance. In this paper, we discuss the neutron shielding design made following the as low as reasonable achievable principle in order to reduce the shut-down dose rate in the interspace and port cell which are human-accessible areas. The design choice for radiation shielding of electronics in the port cell is also discussed. The port maintenance in ITER consists of remote handling operation for the port plug and manual (or assisted-manual) operation for the interspace and port cell areas. The compatibility with the ITER maintenance strategy is investigated for UP18 and the associated issues are addressed. [ABSTRACT FROM AUTHOR]

This paper will demonstrate, through industrial case histories, the application of current signature analysis (CSA) technology to reliably diagnose rotor winding problems in squirrel-cage motors. Many traditional CSA methods result in false alarms and/or misdiagnosis of healthy machines due to the presence of current components in the broken cage winding frequency domain, which are not the result of such defects. Such components can result from operating conditions, motor design, and drive components such as mechanical load fluctuations, speed-reducing gearboxes, etc. Due to theoretical advancements, it is now possible to predict many of these current components, thus making CSA testing less error prone and therefore a much more reliable technology. Reliable detection of the inception of broken cage winding problems, or broken rotor bars, prior to failure allows for remedial actions to be taken to avoid significant costs associated with consequential motor component damage and unplanned downtime associated with such in-service failures. [ABSTRACT FROM AUTHOR]

This paper presents a comparative evaluation of the aging characteristics between a high oleic natural ester dielectric liquid (HONE) and mineral oil based on an accelerated single-temperature thermal aging experiment at 150°C for a period of 3000 hours. The important physical (e.g., viscosity, moisture content, acidity) and dielectric (e.g., power factor, alternating current (AC) dielectric breakdown) properties of both the oils were measured and analyzed at different aging intervals. As expected, results show differences in aging behaviors between mineral oil and the natural ester liquid. The relative moisture content in HONE had stable and lower values during the aging duration as compared to the case of mineral oil, where the relative moisture content increased with the aging duration. Further, unlike the observations in mineral oil, the power factor (PF) and acidity of HONE increased drastically with increasing aging times. The most relevant observation made from this study was that in spite of this significant increase in the PF and acidity of HONE with aging, its AC dielectric breakdown voltage was quite stable, which is not observed in the case of mineral oil. This indicates that for natural ester liquids, higher values of PF (or dielectric dissipation factor) and/or acidity due to aging may not necessarily give a true picture on the dielectric performance of the ester. It is therefore important to note here that the threshold limits of some of the diagnostic parameters which are already established for mineral oil do not apply for ester liquids. [ABSTRACT FROM AUTHOR]

With the increase in electrified traction applications, high-performance electric motor drives are now frequently coupled to gear transmissions in vehicles. It is appropriate to note that these drives have the capability to be used as a built-in sensor to estimate important characteristics of the mechanical system. The techniques to do this proposed in this paper do not require any change in the motor drive sensors and can be performed in real time during continuously changing conditions. By estimating the states of each element as a function of its position, spatial synchronous averaging can be used on each element to identify its unique characteristics, including deterioration. This paper presents the development and evaluation of these technologies and an exploration of the limitations of the proposed technologies. [ABSTRACT FROM PUBLISHER]

This paper discusses the methods for the assessment of ultrasound image quality based on our experiences with evaluating new methods for anatomic imaging. It presents a methodology to ensure a fair assessment between competing imaging methods using clinically relevant evaluations. The methodology is valuable in the continuing process of method optimization and guided development of new imaging methods. It includes a three phased study plan covering from initial prototype development to clinical assessment. Recommendations to the clinical assessment protocol, software, and statistical analysis are presented. Earlier uses of the methodology has shown that it ensures validity of the assessment, as it separates the influences between developer, investigator, and assessor once a research protocol has been established. This separation reduces confounding influences on the result from the developer to properly reveal the clinical value. This paper exemplifies the methodology using recent studies of synthetic aperture sequential beamforming tissue harmonic imaging. [ABSTRACT FROM PUBLISHER]

Forschungszentrum Jülich and partners are developing the ITER core charge exchange spectroscopy (cCXRS) hosted by upper port plug#3 (UPP). The system should withstand loading due to the plasma transients resulting in electromagnetic (EM) forces acting on the UPP and its onboard components. On the other hand, the eddy currents and shock dynamic EM loads occur in the vacuum vessel (VV) and make it vibrate. As a result, it excites the UPP and, consequently, its onboard components. The computational problem is a superposition of these solutions: 1) the deterministically calculated time-history UPP response to the applied EM forces and 2) the UPP response to the VV excitations that are specified as floor response spectra (FRS) at the port stub (attachment to the VV). On the top of this, the EM loads should be combined with the seismic ones which are also specified as an FRS. This paper considers a potential methodology for combining plasma transients with seismic events. A numerical modeling of the UPP hosting a specific cCXRS component is presented. This methodology gives a direct and transparent engineering way to estimate the mechanical strength of the UPP onboard components. The analysis uses port stub FRS input and does not depend on a spectra-to-spectra recalculation procedure (from VV to component attachment) that is well established for the seismic-type response spectra but is not validated for the FRS due to the plasma transients. [ABSTRACT FROM AUTHOR]

Accurate on-board capacity estimation is of critical importance in lithium-ion battery applications. Battery charging/discharging often occurs under a constant current load, and hence voltage versus time measurements under this condition may be accessible in practice. This paper presents a data-driven diagnostic technique, Gaussian process regression for in situ capacity estimation (GP-ICE), which estimates battery capacity using voltage measurements over short periods of galvanostatic operation. Unlike previous works, GP-ICE does not rely on interpreting the voltage–time data as incremental capacity (IC) or differential voltage (DV) curves. This overcomes the need to differentiate the voltage–time data (a process that amplifies measurement noise), and the requirement that the range of voltage measurements encompasses the peaks in the IC/DV curves. GP-ICE is applied to two datasets, consisting of 8 and 20 cells, respectively. In each case, within certain voltage ranges, as little as 10 s of galvanostatic operation enables capacity estimates with approximately 2%–3% root-mean-squared error (RMSE). [ABSTRACT FROM AUTHOR]

This paper presents an application of the rough sets algorithms to the analog systems diagnostics. Multiple methods of discretization and reduction of the data sets obtained from measurements are tested to find effective combinations for diagnostic purposes. Useful features of rough sets are identified. Versatility and scalability of the proposed method are verified, by application to multiple analog systems belonging to various technical domains with different complexities. Practical remarks about fault detection and location in the presented systems are included. This paper is supplemented by conclusions about the effectiveness of the method and its future prospects. [ABSTRACT FROM AUTHOR]

Failure mechanisms of electromechanical systems usually involve several degraded health-states. Tracking and forecasting the evolution of health-states and impending failures, in the form of remaining-useful-life (RUL), is a critical challenge and regarded as the Achilles' heel of condition-based-maintenance (CBM). This paper demonstrates how this difficult problem can be addressed through Hidden Markov models (HMMs) that are able to estimate unobservable health-states using observable sensor signals. In particular, implementation of HMM based models as dynamic Bayesian networks (DBNs) facilitates compact representation as well as additional flexibility with regard to model structure. Both regular HMM pools and hierarchical HMMs are employed here to estimate online the health-state of drill-bits as they deteriorate with use on a CNC drilling machine. Hierarchical HMM is composed of sub-HMMs in a pyramid structure, providing functionality beyond an HMM for modeling complex systems. In the case of regular HMMs, each HMM within the pool competes to represent a distinct health-state and adapts through competitive learning. In the case of hierarchical HMMs, health-states are represented as distinct nodes at the top of the hierarchy. Monte Carlo simulation, with state transition probabilities derived from a hierarchical HMM, is employed for RUL estimation. Detailed results on health-state and RUL estimation are very promising and are reported in this paper. Hierarchical HMMs seem to be particularly effective and efficient and outperform other HMM methods from literature. [ABSTRACT FROM AUTHOR]

This paper proposes a solution to monitor the degradation of a multifunctional microelectromechanical systems (MEMS) sensor (MFS) and to recalibrate the sensor output accordingly. The solution is able to predict the remaining useful life based on the recalibration history. The MFS used is a dual pressure–humidity hybrid sensor where model data have been used to demonstrate the applicability and performance of the proposed method for diagnosis, self-correction, and prognosis. [2015-0316] [ABSTRACT FROM PUBLISHER]

This paper deals with a low-cost diagnostic technique for polymer electrolyte membrane (PEM) fuel cells (FCs), which exploits the ripple produced by power converters to monitor the equivalent ohmic resistance. While the available literature on this topic is focused on constant-frequency control of the power converter (such as pulsewidth modulation), this paper discusses the measurement issues that arise when hysteresis current control is employed for a dc/dc boost converter, which represents the simplest solution from the implementation point of view, and therefore particularly suitable for low-cost applications. The classic frequency-domain analysis for ohmic resistance identification, based on the Fourier transform, is compared with a time-domain analysis based on a simple identification algorithm, and a real-time implementation of the latter is presented. The experimental results are obtained on a single PEM FC, but the extension to FC stacks for commercial applications is also discussed. [ABSTRACT FROM PUBLISHER]

In this paper, a low-cost approach for polymer electrolyte membrane fuel cell (FC) drying and flooding diagnosis based on power converter ripple is presented, suitable to be implemented in commercial applications. If proper signal processing algorithms are employed, the high-frequency ripple inherently produced by switch-mode converters allows one to monitor the FC ohmic resistance, which is a good indicator for membrane drying, while an ad hoc switching control of the converter allows one to monitor also the low-frequency impedance, which is an indicator for cell flooding. This technique is tested with a dc/dc boost converter directly connected to a single cell, discussing how different FC operation modes (such as constant current or constant voltage) may affect the sensitivity required to the diagnostic algorithm to correctly recognize drying and flooding occurrences. [ABSTRACT FROM PUBLISHER]

This paper presents a hybrid algorithm for separation of two simultaneous partial discharge (PD) sources of oil-paper insulation based on S transform (ST) and affinity propagation clustering (APC). Similarities between PD pulses are acquired by comparisons of the corresponding ST-amplitude (STA) matrices, which are input of APC to realize the PD pulses separation and obtain two sub-groups of PD pulses having similar time-frequency characteristics. A classification-based model for separation results validation are developed using a support vector machine with particle swarm optimization (PSO-SVM) classifier and 27 phase-resolved partial discharge (PRPD) statistical features. Artificial defect models are made to simulate two PD sources simultaneously active. Several PD data of different two simultaneous PD sources are acquired in laboratory and adopted for algorithm testing. It is shown that ST computes very fast and is suitable for online PD applications. The separation results of PD data produced in laboratory are verified by the developed validation model, which demonstrate that ST combined with APC can effectively eliminate pulse-shaped noises (PSN) and separate pulses of two simultaneous PD sources. Comparisons with typical separation methods from the state of the art provide better separation performance of the proposed ST combined with APC algorithm for two simultaneous PD sources. The obtained results in this work provide a solid basis for the data mining technique that can be used to facilitate PD diagnosis of transformers. [ABSTRACT FROM AUTHOR]

The Hybrid Illinois Device for Research and Applications (HIDRA) is a toroidal fusion device at the University of Illinois at Urbana–Champaign, Urbana, IL, USA. HIDRA is the former WEGA stellarator that was operated at the Max Planck Institut für Plasmaphysik, Greifswald, Germany. The machine is a five-period, $l=2, m=5$ stellarator, with major radius $R_{0}=0.72$ m, and minor radius $a=0.19$ m. Initial heating is achieved with 2.45-GHz electron cyclotron resonance heating and an on-axis magnetic field of $B_{0}=0.087$ T that can go as high as $B_{0}=0.5$ T. HIDRA has the ability to operate as both a stellarator and a tokamak, initially operating in the stellarator mode. The focus of research on HIDRA will be doing dedicated studies on plasma-material interactions (PMIs) using the wealth of knowledge and experience at the Center for Plasma Material Interactions, Urbana, IL, USA. In early 2016, the first experiments were performed on HIDRA. This paper presents some of the first results obtained from the machine such as initial magnetic fields’ measurements and plasma discharges. It also shows the development of the control system being currently implemented and introduces HIDRA-materials analysis tool, the in situ PMI facility that will be mounted on HIDRA in the near future to further enhance the diagnostics and material testing experiments meant to be conducted on the machine. [ABSTRACT FROM AUTHOR]

The occurrence of corona effect is an important indication that an insulator probably has malfunction. Thus, the corona detection can help to diagnose problems in insulators, which might cause serious damage to the power distribution system, such as the sudden interruption of service. Artificial neural networks (ANN) are machine learning techniques for classifying patterns into categories. This paper evaluated the application of neural networks for corona detection in high voltage polymeric insulators using ultrasonic emissions. To perform the capture of these data, a specific electronic circuit was developed to capture the ultrasonic signals tuned in the 40 kHz. The results permit to infer that neural networks showed high generalizability and looks to be a promising technique for this type of problem, using ultrasonic frequencies as the data source. [ABSTRACT FROM AUTHOR]

Estimating nutrient content in plants is a crucial task in the application of precision farming. This work will be more challenging if it is conducted nondestructively based on plant images captured in the field due to the variation of lighting conditions. This paper proposes a computational intelligence image processing to analyze nitrogen status in wheat plants. We developed an ensemble of deep learning multilayer perceptron-using committee machines for color normalization and image segmentation. This paper also focuses on building a genetic-algorithm-based global optimization to fine tune the color normalization and nitrogen estimation results. We discovered that the proposed method can successfully normalize plant images by reducing color variabilities compared to other color normalization techniques. Furthermore, this algorithm is able to enhance the nitrogen estimation results compared to other non-global optimization methods as well as the most renowned SPAD meter based nitrogen measurement. [ABSTRACT FROM AUTHOR]

It is well known in the market that the copper rotor motor can give good efficiency at par with the new era motors, and can handle higher temperatures to qualify for electric vehicle application. Being a heavy metal, die-cast copper rotor manufacturing needs absolute care for faithful rotor production. In this paper, the common faults in copper die-cast processing are identified and sufficient monitoring methods are suggested in a three-stage inspection. The final stage consists of a rotor quality test system, which detects most of the problems found in copper die-cast rotors. This rotor quality test system analysis helps to optimize the rotor manufacturing process and avoid the circumstances of fitting an inferior rotor in the motor assembly. [ABSTRACT FROM PUBLISHER]

This paper proposes a scalable and unsupervised feature engineering method that uses vibration imaging and deep learning. For scalability, a vibration imaging approach is devised that incorporates data from systems with various scales, such as small testbeds and real field-deployed systems. Moreover, a deep learning approach is proposed for unsupervised feature engineering. The overall procedure includes three key steps: 1) vibration image generation; 2) unsupervised feature extraction; and 3) fault classifier design. To demonstrate the validity of the proposed approach, three case studies are conducted using an RK4 rotor kit and a power plant journal bearing system. By incorporating smaller-system data as well as real-system data, the proposed approach can substantially increase the applicability of the fault diagnosis method while maintaining good accuracy. Moreover, the time and effort needed to develop a diagnostic approach for other rotor systems can be reduced considerably. [ABSTRACT FROM AUTHOR]

In this paper, we propose and use an experimental method permitting the measurement of optical depth of a self-absorbed spectral line emitted from laser-induced plasma on the surface of an aqueous solution. Using well-known equations describing the radiatif transfer and the evolution with the optical depth of the relative uncertainty on the measurement of line intensity and on the half width at half maximum, we have also deduced the uncertainty on the measurement of electron temperature and the electron density. An application to the diagnostics of this plasma has been realized, and we show the reliability of the spectroscopic measurements. [ABSTRACT FROM PUBLISHER]

Radome diagnostics are acquired in the design process, the delivery control, and in performance verification of repaired and newly developed radomes. A measured near or far field may indicate deviations, e.g., increased side-lobe levels, but the origins of the flaws are not revealed. In this paper, radome diagnostics is performed by visualizing the equivalent surface currents on the 3-D radome body, illuminated from the inside. Three different far-field measurement series at 10 GHz are employed. The measured far field is related to the equivalent surface currents on the radome surface by using a surface integral representation. In addition, a surface integral equation is employed to ensure that the sources are located inside the radome. Phase shifts, insertion phase delays (IPD), caused by patches of dielectric tape attached to the radome surface, are localized. Specifically, patches of various edge sizes (0.5–2.0 free-space wavelengths), and with the smallest thickness corresponding to a phase shift of a couple of degrees are imaged. [ABSTRACT FROM PUBLISHER]

Typically, in laboratory and diagnostics tests focused on measuring partial discharges, a pure sinusoidal voltage waveform is assumed. However, in practice the spectral content of the applied voltage is rarely so ideal and additional spectral components have a significant impact on the discharge behavior in electrical insulation systems. In this paper the influence of voltage harmonics on partial discharge behavior and pattern evolution is analyzed. The presented experiments were conducted on a transformer installed in a municipal network and on specimens representing defects in a transformer insulation system, in the form of a micro blade protrusion on a winding conductor and an embedded gas inclusion. The experimental results showed that various harmonic compositions superimposed on the fundamental sinusoidal waveform have a significant impact on PD intensity and maximum charge. In consequence, PD pattern phase and amplitude distributions are distorted and calculated statistical parameters are changed. The rough parameters reflecting the waveform spectral quality, such as THD, are rather superficial and do not provide a unique and reliable signature of the applied voltage in terms of phase angle variations. In certain environments, neglecting harmonic content in the voltage may lead to a misleading interpretation and assessment of partial discharge severity. A complete knowledge of harmonic content is essential and critical in conducting a proper assessment of the impact of PD, including acceptability criteria and compatibility with the standards. [ABSTRACT FROM PUBLISHER]

Optimization of combustion processes holds the promise of maximizing energy efficiency, at the same time lowering fuel consumption and residual gases emissions. In this context, the current common operation setting in combustion processes could be improved by the introduction of passive optical sensors, which can be located close the flame, thus eliminating the inherent transport delay in current setups that only infer the combustion quality by measuring residual gases emissions. However, there is a tradeoff for flame detection between spatial-spectral resolutions, depending on the optical sensor scheme. In this paper, we present the fundamentals to avoid this constraint, obtaining a combined high spectral and spatial resolution measurement suitable for combustion diagnostics and control. The core of this proposal is to use the flame images from a low-spectral resolution charge-coupled device camera, combined with a spectral recovery method. This method is based on the off-line samples measured on the continuous component of flame spectra, providing a set of vector basis to estimate a calibrated flame spectra at each pixel. The results of the spectral recovery process verify the suitability of the method in terms of goodness-of-fit coefficient and root mean square error metrics, enabling hyper-spectral measurements based on the combination of different optical sensors. Then, continuous estimated spectra along the flame are used to calculate the energy transfer released by radiation, useful for combustion diagnostics. [ABSTRACT FROM PUBLISHER]

Electromagnetic induction coils are widely used in a variety of applications, many of them safety-critical. The insulation around the wire in an electromagnetic coil accounts for a significant portion of the failures in solenoid-operated valves and in electric motors. This paper presents a method of detecting the degradation of insulation used in low-voltage applications by assessing changes in impedance responses. The results indicate that coil impedance, resolved into resistance and reactance, evolves differently when the coil is subjected to different loading conditions, which reflects insulation degradation signatures due to different failure mechanisms. This method can be used to assess the insulation life of an electromagnetic coil, allowing replacement prior to the formation of harmful shorts or critical coil opens. [ABSTRACT FROM PUBLISHER]

Conventional direct current arc plasma spray torches generate highly unstable plasma jets. This leads to some difficulties with control of coating properties especially when injecting liquid feedstock for the elaboration of finely structured coatings. At constant applied current, a properly designed arc plasma torch can work in self-sustained pulsed mode that produces large amplitude oscillations of the arc, which are interrupted by very repeatable restrikes. This paper investigates the influence of the modulation of the applied current on the arc stability. Electrical and acoustic diagnostics permit to show that amplification of arc oscillation and a stabilizing mechanism occur when the arc current frequency approaches the torch resonance frequency. Time-resolved optical emission spectroscopy is used to determine temperature and enthalpy profiles close to the resonance and the enthalpy modulation. [ABSTRACT FROM PUBLISHER]

It is difficult to apply conventional online motor current signature analysis techniques for diagnosis of rotor faults for closed-loop induction motor drives for many applications due to the masking effect of the feedback current controller and/or variable frequency or load operation. Relying solely on traditional offline inspection techniques during regular maintenance does not allow frequent monitoring of rotor problems and is inconvenient since it requires rotor disassembly and/or manual rotor rotation. In this paper, a new automated technique for testing voltage source inverter-fed squirrel-cage induction machines at a standstill for rotor faults is proposed. The main concept is to use the inverter to excite the machine with a pulsating field at a number of angular positions to observe the variation in the impedance pattern due to broken rotor bars, whenever the motor is stopped. An experimental study on a 7.5-hp induction motor verifies that broken bars can be detected with high sensitivity and reliability. It will be shown that the proposed method can provide automated and reliable assessment of rotor condition frequently without motor disassembly, manual rotation, or additional instrumentation. The proposed test can also provide rotor quality assessment independent of variations in motor or load operating conditions since it is a standstill test. [ABSTRACT FROM AUTHOR]

This paper presents an application of induction motor mechanical speed and load torque observers in high-speed train drives. The observers are applied for a 1.2-MW electric drive with an induction motor. The goal of using such observers is to utilize computed variables for diagnostic purposes of speed sensors and torque transmission system. The concept of diagnostic system is presented in this paper, and proper criteria are proposed. The suggested system is designed to work without a speed sensor in the case of existing sensor faults. Monitored motor load torque is used to limit the maximum motor torque in the case of existing problems in the gearbox. The results of simulation and experimental investigations for a 1.2-MW induction motor drive are presented. [ABSTRACT FROM AUTHOR]

Localized heating caused by damage in the laminations or interlaminar insulation of the stator core increases the core losses and can lead to machine failure. Therefore, it is important to monitor the quality of the stator core for reliable and efficient operation of the machine. The methods currently available for core quality assessment are inconvenient since they require an outage and the machine to be disassembled or operated under no-load conditions. In this paper, a new method for monitoring the quality of the stator core for inverter-fed machines without motor disassembly or operation is proposed. The main concept is to use the inverter to apply a set of test signals to assess the quality of the core whenever the motor is at standstill. A set of high-frequency pulsating magnetic fields is produced using the inverter, and the power loss is observed as a function of field circumferential position to detect core problems. An experimental study on a 10-hp induction motor verifies that local interlaminar core faults can be detected with high sensitivity. The proposed technique is expected to provide a simple solution for frequent stator-core quality assessment without motor disassembly, motor operation, or additional hardware for reliable and efficient operation of inverter-fed induction machines. [ABSTRACT FROM AUTHOR]

The advent of complementary metal-oxide-semiconductor (CMOS) based lab-on-chip (LoC) technology, which combines on-chip sample handling with integrated sensing, heralds the production of revolutionary biomedical devices capable of detecting pathogenic DNA at the point-of-care (PoC) and diagnosing infectious diseases. The ion-sensitive field effect transistor’s (ISFET) inherent sensitivity to hydrogen ions makes them ideal for pairing with DNA amplification reactions to form adept LoC diagnostic devices. This paper reviews the state-of-the-art of CMOS-based LoC devices for DNA detection and discusses electric field actuation as an opportunity for enhanced sensing capabilities. Following our previous review centred on instrumentation, we provide an overview of reported architectures in recent years which have led to portable ISFET-based devices for PoC diagnostics. We then discuss the use of dielectrophoresis (DEP) for electric field manipulation of DNA using low-power, CMOS-compatible microelectrodes. The technique enables positioning of DNA close to ISFET sensing regions to localise hydrogen ion production. This provides a signal boost to the ISFETs that lowers the limit-of-detection and time-to-result of the device, as well as providing a means of on-chip sample preparation. Major challenges include electrode spoiling reactions, hindering electrokinetic effects, and the strong dependence of trapping efficiency on applied voltage. The combination of an ISFET LoC platform with a DEP actuation system is expected to represent a landmark step for the next generation of PoC diagnostics devices. [ABSTRACT FROM AUTHOR]

Automation in power generation, distribution and transmission has advanced from a semi-automated to fully autonomous approach. This work presents some of the implementations of a transmission and distribution transformer monitoring model for the creation of a management system of these assets, whose topology was elaborated based on IEC 61850. The implementation incorporates the creation of two new LN ' s,: (B) - Diagnosis of the Degradation of the Isolation System of Transformers; (E) - Life Expectancy of the Isolation System of Transformers, post asset recovery action. In order to subsidize the structure of the new LN's Groups, a pilot asset management system was implemented for two transformers from Copel Transmissão e Distribuição (Pilarzinho Substation in Curitiba, Paraná). In this work two new LN's were proposed for groups (B) and (E) respectively: "Degradation of the Transformer Isolation System (paper-oil) - BIOP", and "Remaining Utility Life of the Transformer Insulation System - ELTR ". These LNs were used in the experimental electronic area (IEDs) of the pilot project area, using the Hadrom Xtorm Remote Terminal Unit (ALTUS, IEC 61850 compatible) and evaluated and validated in the field. [ABSTRACT FROM AUTHOR]

Vibration signals generated during circuit breaker (CB) closing or opening operations contain rich information of operating mechanism (OM), transmission mechanism, and interrupter(s). Effective feature extraction method can mine the information as a criterion for diagnosis and maintenance. However, due to the very complicated mechanical system and extremely short operation time of CB, the vibration signal is highly nonlinear and non-stationary, which makes it very difficult to precisely extract effective features for machinery fault diagnosis. Chaotic nonlinear dynamic technique provides a new way to study the complex vibration signals. In this paper, phase space reconstruction is utilized to study the effect of faults on the chaotic attractor (the trajectories in multidimensional phase space) behavior. The power spectrum and Lyapunov exponent proof the existence of chaos in the CB's vibration signals. The invariant measures and ergodic quantities such as the largest Lyapunov exponent (LLE), correlation dimension (CD) and Kolmogorov entropy (KE) which can be estimated on the reconstructed attractor are presented as a set of new features for fault diagnosis. The estimation of these features was tested on the experimental data sets recorded from a 12-kV, 1250-A vacuum CB and a 252-kV, 4000-A SF6 CB, respectively. [ABSTRACT FROM AUTHOR]

Gears form a critical part of many electromechanical systems. Since gear faults cause vibrations, and vibration-based diagnostics are very reliable, this has traditionally been the most commonly used approach to detecting gear faults. However, it is expensive due to the use of high-priced accelerometers and sensor wiring. This paper proposes an alternative way of detecting faults in gears coupled to brushless dc motors by monitoring either the motor current or voltage. It will be shown that gear faults create unique spectral components in the voltage and current spectrums. The faults investigated include damage to gear teeth and loss of lubrication. Experimental and simulation results demonstrate that motor current/voltage signature analysis is a viable tool to detect these gear faults and is a cheaper alternative than vibration-based fault-detection scheme. [ABSTRACT FROM AUTHOR]

Water flooding is one of the main causes of performance degradation for polymer electrolyte membrane fuel cells (FCs), and its prompt detection is therefore important to guarantee optimal FC operation. This paper aims at comparing the most common methods for flooding diagnosis, which are based on electrical or gas pressure measurements. Their differences in terms of sensitivity to flooding are investigated, primarily focusing on their suitability for its early detection. In particular, the differences between anodic and cathodic pressure drop measurements are highlighted, as well as their relationship with the FC electrical output. The experimental results show that cathodic pressure measurements are the most convenient choice for early flooding detection. Measurements have been performed on a single cell, since it allows an easier interpretation of the results, although the applicability of the considered methods to FC stacks for commercial applications is also discussed. [ABSTRACT FROM AUTHOR]

Partial discharges (PD) are a significant contributor to insulation failure within power transformers, and as such, the localizing of a PD source can be of critical importance when it comes to a transformer's assessment and repair. One PD localization technique which is acquiring increased attention is the application of an ultra high frequency (UHF) sensor to trigger an acoustic array. This hybrid approach helps to overcome the poor signal to noise sensitivity issues commonly associated with externally mounted acoustic sensors by leveraging the benefits offered by an internally mounted UHF sensor to trigger PD events. The internally mounted UHF sensor is insensitive to external corona discharges which typically are the largest disturbance source associated with conventional measurements. A problem with this hybrid methodology is when there are multiple PD. The research presented in this paper demonstrates that UHF PD signals are primarily independent of the type of PD source. The research also demonstrates that UHF PD signals inherit signal characteristics which are particular to their location within a transformer structure, and inherit distortion characteristics which are particular to their journey from source to destination. As a result it is proposed that the correlation of UHF PD signatures can be used for discrimination purposes in order to identify individual PD sources within a transformer using a single UHF sensor. This could then be used in conjunction with acoustic measurement techniques to sequentially localize multiple PD within a power transformer which formerly has proven to be a technical challenge. [ABSTRACT FROM AUTHOR]

Power transformers are designed to withstand system abnormalities such as over voltages and external short-circuits. Transformer monitoring and diagnostics are the effective techniques in preventing the eventual failures and contribute to ensure the plant's reliability. Transformer life mainly depends on the integrity of its solid insulation (cellulose). The solid insulation in transformers degrades with time at rates which depend on the temperature and the amount of moisture, oxygen and acids in the insulation system. Moisture and oxygen cause the paper insulation to decay much faster than normal. Moisture in a transformer accelerates the aging process and causes severe deterioration in the mechanical and electrical properties of insulation system. The aging of paper insulation is irreversible. The degree of polymerization value is a main relation between insulation deterioration and formation of aging products. To predict a failure or an unusual behavior, an accurate interpretation of monitoring, diagnostics and maintenance data is required. The monitoring of insulation system and verification of core and winding mechanical integrity allow optimization of the lifecycle management of an asset. This paper presents an investigation and condition assessment of 152 MVA, 512 kV, 1-phase, 2-winding generator step-up transformer having a history of combustible gases. [ABSTRACT FROM AUTHOR]

Most of ITER’s diagnostics will be provided with viewing lines (optical, microwave, and spectroscopic) for the monitoring of key characteristics of the plasma or for the achievement of physical measurements inside the vacuum vessel. The nature of the physical signal transmitted through the viewing lines requires the implementation of window assemblies incorporating nonmetallic window. Placed at the vacuum boundary, the window assembly shall also ensure the vacuum integrity required for the plasma. Moreover, the diagnostic window assemblies form part of the ITER primary confinement boundary, and thus, directly related to the nuclear safety. This paper gives an overview of their design and related on-going engineering assessments by analysis or tests in the final design phase. [ABSTRACT FROM AUTHOR]

Determining the state of health of fuel cell systems is essential to improving its performance and life expectancy. This paper presents the development of a new rapid online condition monitoring system using optimized broadband impedance spectroscopy (OBIS). The hardware was specifically designed to be low cost and scalable to meet the needs of single cell and stack level testing. It is shown how classic electrochemical impedance spectroscopy (EIS) is limited when testing under extreme nonlinear conditions. The design process of the broadband signal is tailored for polymer electrolyte membrane fuel cell diagnostics in order to minimize measurement time and system disturbance while maximizing accuracy. The long measurement time of standard EIS makes it impractical to use for rapid fault diagnosis, and it is shown how the OBIS system is able to deliver impedance measurements under conditions where EIS cannot be applied. The proposed system is tested for an array of possible operational phenomena and faults and the results compared with that obtained from a commercial frequency response analyzer to demonstrate performance. [ABSTRACT FROM PUBLISHER]

Today, fast and accurate diagnosis through portable and cheap devices is in high demand for the general healthcare. Lab-on-chips (LoCs) have undergone a great growth in this direction, supported by optical imaging techniques more and more refined. Here we present recent progresses in developing imaging tools based on coherent imaging microscopy that can be very useful when applied into biomicrofluidics. In some cases, the optical tweezers (OT) technique is combined with digital holography (DH), thus offering the possibility to manipulate, analyze, and measure fundamental parameters of different kinds of cells. This approach can open the route for rapid and high-throughput analysis in label-free microfluidic devices and for prognostic based on cell examination, thus allowing advancements in biomedical science. [ABSTRACT FROM PUBLISHER]