Two decades of condition monitoring methods for power devices

Condition monitoring (CM) of power semiconductor devices enhances converter reliability and customer service. Many studies have investigated the semiconductor devices failure modes, the sensor technologies, and the signal processing techniques to optimize the CM. Furthermore, the improvement of power devices’ CM thanks to the use of the Internet of Things and artificial intelligence technologies is rising in smart grids, transportation electrification, and so on. These technologies will be widespread in the future, where more and more smart techniques and smart sensors will enable a better estimation of the state of the health (SOH) of the devices. Considering the increasing use of power converters, CM is essential as the analysis of the data obtained from multiple sensors enables the prediction of the SOH, which, in turn, enables to properly schedule the maintenance, i.e., accounting for the trade-off between the maintenance cost and the cost and issues due to the device failure. From this perspective, this review paper summarizes past developments and recent advances of the various methods with the aim of describing the current state-of-the-art in CM research

Degradation studies on different pigments and binders: new approaches to diagnostics in cultural heritage

Studying the state of degradation, alteration and conservation of an artwork is the starting point of a restoration process. This first step is commonly known in the field of cultural heritage as "diagnostics". A careful diagnosis allows choosing the best restoration approach for a sample under examination. The diagnostics of an artwork permits not only a complete characterization of materials realized by an artist, but also the identification of the degradation products generated over time. The main intent of this work is to expand the diagnostic research both from a descriptive point of view for the degradation process of the painted surface, and from the point of view of new approaches and methodologies for diagnostics. For what concerns the first one, we worked with two main purposes: kinetics studies in the case of San Giovanni white with the help of a non-invasive technique (Raman spectroscopy), and the characterization of the degradation path and individuation of the respective alteration products in the case of Red vermilion and Cd-pigments, always favouring the choice of a non-destructive techniques, conventional or not, such as non-linear optics. Regarding the development of new approaches and methodologies, we studied the photo-acoustic method coupled with SORS (Spatially Off-set Raman Spectroscopy) as a new tool for stratigraphy analyses of frescoes. This work is carried out in collaboration with the research centre FORTH (Crete) and it has been tested on artificial frescoes mock-ups and on real frescoes fragments, in order to obtain compositional information and stratigraphic imaging on the samples

Challenges and New Trends in Power Electronic Devices Reliability

The rapid increase in new power electronic devices and converters for electric transportation and smart grid technologies requires a deepanalysis of their component performances, considering all of the different environmental scenarios, overload conditions, and high stressoperations. Therefore, evaluation of the reliability and availability of these devices becomes fundamental both from technical and economicalpoints of view. The rapid evolution of technologies and the high reliability level offered by these components have shown that estimating reliability through the traditional approaches is difficult, as historical failure data and/or past observed scenarios demonstrate. With the aim topropose new approaches for the evaluation of reliability, in this book, eleven innovative contributions are collected, all focusedon the reliability assessment of power electronic devices and related components

Non-Destructive Evaluation of Aerospace Composites

Five methods of non-destructive material evaluation (NDE) were used to inspect various forms of damage commonly found in aerospace fiberglass composites: voids, edge and sub-surface delaminations, surface burning, and cracking. The images produced by X-ray, X-ray Computed Tomography, terahertz (THz) imaging, ultrasound, and flash IR thermography were analyzed for the detection of defects. Test results and analysis of each NDE method\u27s capabilities provide a comparison study of conventional techniques versus the emerging technology of THz imaging for the non-destructive evaluation of aerospace composite materials. A comparison guide to the five methods\u27 damage detection effectiveness for fiberglass composites is provided by defect type

Resident research associateships. Postdoctoral and senior research awards: Opportunities for research at the Jet Propulsion Laboratory

Opportunities for research as part of NASA-sponsored programs at the JPL cover: Earth and space sciences; systems; telecommunications science and engineering; control and energy conversion; applied mechanics; information systems; and observational systems. General information on applying for an award for tenure as a guest investigator, conditions, of the award, and details of the application procedure are provided

Infrastructure of Synchrotronic Biosensor Based on Semiconductor Device Fabrication for Tracking, Monitoring, Imaging, Measuring, Diagnosing and Detecting Cancer Cells

Copper Zinc Antimony Sulfide (CZAS) is derived from Copper AntimonySulfide (CAS), a famatinite class of compound. In the current paper, thefirst step for using Copper, Zinc, Antimony and Sulfide as materials inmanufacturing synchrotronic biosensor-namely increasing the sensitivity of biosensor through creating Copper Zinc Antimony Sulfide, CZAS(Cu1.18Zn0.40Sb1.90S7.2) semiconductor and using it instead of CopperTin Sulfide, CTS (Cu2SnS3) for tracking, monitoring, imaging, measuring,diagnosing and detecting cancer cells, is evaluated. Further, optimization oftris(2,2'-bipyridyl)ruthenium(II)(Ru(bpy)32+) concentrations and CopperZinc Antimony Sulfide, CZAS (Cu1.18Zn0.40Sb1.90S7.2) semiconductor as two main and effective materials in the intensity of synchrotron fortracking, monitoring, imaging, measuring, diagnosing and detecting cancercells are considered so that the highest sensitivity obtains. In this regard,various concentrations of two materials were prepared and photon emissionwas investigated in the absence of cancer cells. On the other hand, ccancerdiagnosis requires the analysis of images and attributes as well as collectingmany clinical and mammography variables. In diagnosis of cancer, it isimportant to determine whether a tumor is benign or malignant. The information about cancer risk prediction along with the type of tumor are crucialfor patients and effective medical decision making. An ideal diagnosticsystem could effectively distinguish between benign and malignant cells;however, such a system has not been created yet. In this study, a model isdeveloped to improve the prediction probability of cancer. It is necessary tohave such a prediction model as the survival probability of cancer is highwhen patients are diagnosed at early stages

Laser spectroscopy for breath analysis : towards clinical implementation

Detection and analysis of volatile compounds in exhaled breath represents an attractive tool for monitoring the metabolic status of a patient and disease diagnosis, since it is non-invasive and fast. Numerous studies have already demonstrated the benefit of breath analysis in clinical settings/applications and encouraged multidisciplinary research to reveal new insights regarding the origins, pathways, and pathophysiological roles of breath components. Many breath analysis methods are currently available to help explore these directions, ranging from mass spectrometry to laser-based spectroscopy and sensor arrays. This review presents an update of the current status of optical methods, using near and mid-infrared sources, for clinical breath gas analysis over the last decade and describes recent technological developments and their applications. The review includes: tunable diode laser absorption spectroscopy, cavity ring-down spectroscopy, integrated cavity output spectroscopy, cavity-enhanced absorption spectroscopy, photoacoustic spectroscopy, quartz-enhanced photoacoustic spectroscopy, and optical frequency comb spectroscopy. A SWOT analysis (strengths, weaknesses, opportunities, and threats) is presented that describes the laser-based techniques within the clinical framework of breath research and their appealing features for clinical use.Peer reviewe

The Boston University Photonics Center annual report 2007-2008

This repository item contains an annual report that summarizes activities of the Boston University Photonics Center in the 2007-2008 academic year. The report provides quantitative and descriptive information regarding photonics programs in education, interdisciplinary research, business innovation, and technology development. The Boston University Photonics Center (BUPC) is an interdisciplinary hub for education, research, scholarship, innovation, and technology development associated with practical uses of light.The following report summarizes activities of the Boston University Photonics Center (BUPC) during the period July 2007 through June 2008. These activities span the Center’s complementary missions in education, research, technology development, and commercialization. Faculty research activity reached an all time high when evaluated by the accepted metrics of external funding, scholarly publications, honors and awards. The Center’s educational programs were bolstered by two summer programs hosting more than 40 undergraduate interns, and by the renewal of a competitive graduate fellowship program sponsoring ten BUPC graduate fellowships. In technology development, the prototype RedOwl sniper detection system pioneered by Center faculty, staff, and industry partners was field-tested by the US Department of Defense. RedOwl has been officially transitioned to industry partners for further commercial development along with the soldier wearable Enhanced Acoustic Gear for Locating Enemies (EAGLE) system. Three defense/security prototypes were developed by BUPC to address critical national defense needs in the past year. Four faculty development projects were supported in collaboration with the Army Research Laboratory’s Sensors and Electron Devices Directorate (ARL-SEDD) to fill the technology pipeline for our future defense-related prototyping efforts. The Center’s business incubator is at capacity with various technology companies ranging from photonics to life sciences. The incubator provides a stimulating intellectual environment, outstanding facilities, and professional business expertise to participating companies