Partial Discharge in Electronic Equipments

Tato disertační práce se věnuje studiu částečných výbojů (PD) způsobených poklesem spolehlivosti a životnosti elektronických zařízení a systémů. Diagnostika PD je dnes známá metoda pro vysoké napětí u vysoko-výkonných zařízení. V případě elektronických zařízení PD testování není ale běžně používáná metoda, přestože je zde také potenciál pro vysoké elektrické zatížení vzhledem k velmi krátké vzdálenosti. Tato práce je zaměřena na vyšetřování PD činnosti u elektronických zařízení. Bylo navrženo a provedeno pracoviště pro diagnostiku PD v elektronických zařízeních. Pracovní frekvence se pohybuje od několika stovek Hz až 100 kHz. Maximální amplituda PD testovaného napětí je vyšší než 10 kV. Navzdory jednoduché konstrukci toto zařízení přináší vysokou spolehlivost měření. Více než 300 PD testů bylo provedeno na různých elektronických zařízeních a elektronických součástí,např. na planárních transformátorech a elektronických komponentách používaných při vysoko-napěťových měničíchThis dissertation thesis is devoted to study of partial discharge (PD) caused decrease of reliability and lifetime of electronic equipments and systems. PD diagnostic is nowadays well known method for high voltage high power equipments but in case of electronic devices PD testing it is not used routinely despite that there is also a potential for high electric load due to extremely short distances. The risk of PD caused failure is here extremely high because of high working frequency and consequently high repetition rate of PD events. Therefore, this work is focused on investigation of PD activity in electronic equipments. The workplace for PD diagnostic in electronic devices based on switched power supply was designed and made. Working frequency ranges from several hundreds of Hertz up to 100 kHz. The maximal amplitude of PD testing voltage is higher than 10 kV. Despite the simple design this equipment brings high repeatability and reliability of measurement. More than 300 PD tests were made on different electronic devices and electronic components, on planar transformers, and on components for voltage gate drivers for use in high voltage power converters. Possibilities of PD tools in investigation and engineering ofd insulation systems were demonstrated.

Alvin instrumentation

Also published as: 1967 NEREM record : Institute of Electrical and Electronics Engineers 9 (1967): 196-197THIS PAPER DESCRIBES the equipments used to establish the relative position of ALVIN from her mother ship, the R/V LULU. Operating procedures used at sea are also discussed. A recent review within the Deep Submergence Research Vehicle Program at WHOI established a set of conclusions and guidelines, for internal use, governing the ALVIN locating equipments and procedures.The Office of Naval Research under Contract Nonr- 3484(00)

JUMPSAT: Qualifying three equipments in one Cubesat mission

We work on a student 3U Cubesat mission, called JUMPSAT, expected for 2017. This is a collaborative project involving both institutions (CNES, ONERA) and schools (ISAE, TELECOM Bretagne). The different equipments to qualify are the Supaero Star Tracker, which measures stars’ luminosity to infer the satellite’s attitude, a detector for particles trapped in the Earth magnetic field designed by the ONERA, and the AOCS. Uplink and Downlink communications will be provided during the mission by the HETE Primary Ground Stations. JUMPSAT is the first Cubesat which needs a three axis attitude control, which involves an innovative mission analysis, to overcome all these constraints. The mission analysis deals with the orbit’s determination, the Cubesat’s structure, the power strategy, and the visibility balance. The particles detector is the only constraint for the altitude of the satellite: we can get meaningful data only at altitudes higher than 700 km. Moreover, the most interesting zones are South Atlantic and poles. But a circular orbit with this altitude does not respect the LOS (French space act).The structure of the Cubesat is also hard to define. To get information from the satellite, we need an antenna, and an attitude and orbital control system to point the antenna at the ground station and the Star Tracker at the stars. Solar Panels cannot be opened out because of the micro elements that could be settled on the particles detector. However, fixed solar panels are not very efficient to recharge batteries. The power balance shows critical problems: both attitude control system and the Star Tracker consume a lot, and cannot work at the same time during the whole orbit. However, all the components are linked: the Star Tracker is not efficient if the satellite attitude is not stabilized; the antenna functioning must be synchronized with visibilities by the ground station. Anyway, the visibility balance stresses the point that a ground station at Toulouse would be particularly welcome. We need also to take into account phenomena of eclipse and satellite drift. To conclude, our mission analysis is deeply constrained by the equipments we want to qualify. Our task is to find the optimal orbit, suggest a power strategy considering the orbital constraints and components’ physical parameters, and to study the visibility balance. It is a real challenge in terms of power consumption, architecture, orbital strategy for such a small satellite

JUMPSAT: Qualifying three equipments in the CubeSat mission

JUMPSAT is a 3-Unit CubeSat mission expected for launch in 2017. It is a collaborative project involving the French research institutes CNES and ONERA as well as two universities, the Institut Supérieur de l'Aéronautique et de l'Espace and TELECOM Bretagne. The main mission objectives are the technological verification of both the three-axis attitude control system as well as the verification of two embedded payloads: A low cost Star Tracker developed by ISAE-Supaero for future small satellite missions and a directional radiation sensor for precise mapping of the Earth radiation belt. This article focuses on the mission concept and the status of the mission design in fall 2013. Main mission parameters are introduced, with emphases on the characteristic properties of the Jumpsat mission, as for example the choice of a sun-synchronous elliptical low-Earth Orbit, which is necessary to be in compliance with the payload requirements and at the same time to ensure space debris prevention. Furthermore, due to the limited observation time of a polar satellite, it was decided to utilize a distributed ground station network on S-band frequency for ensuring the necessary communication bandwidth for up- and downlink. The space segment will be equipped with deployable solar panels for improving the thermal and power budget of the overall system. Finally, a brief overview of the specifications and design of the attitude control system and both payloads are also given in the article

Energy-Efficient Resource Allocation for Device-to-Device Underlay Communication

Device-to-device (D2D) communication underlaying cellular networks is expected to bring significant benefits for utilizing resources, improving user throughput and extending battery life of user equipments. However, the allocation of radio and power resources to D2D communication needs elaborate coordination, as D2D communication can cause interference to cellular communication. In this paper, we study joint channel and power allocation to improve the energy efficiency of user equipments. To solve the problem efficiently, we introduce an iterative combinatorial auction algorithm, where the D2D users are considered as bidders that compete for channel resources, and the cellular network is treated as the auctioneer. We also analyze important properties of D2D underlay communication, and present numerical simulations to verify the proposed algorithm.Comment: IEEE Transactions on Wireless Communication

Adsorption of MS2 bacteriophage on ultrafiltration membrane laboratory equipments

Virus adsorption has been quantified (i) on different materials including various containers made of glass, plastic or stainless steel and hollow fiber membranes made of polyethersulfone, polysulfone, PVDF or cellulose acetate (with two configurations: in/out and out/in and various molecular weight cut-offs); and (ii) on the filtration equipment. The selected virus is MS2 bacteriophage used as a model to estimate viral survival in water or to quantify virus elimination by membrane filtration. A series of experiments have been conducted with suspensions of MS2 at different concentrations prepared in a sterilized saline solution (8 g/L of KCl) or in sterilized distilled water. This study has shown that the most appropriate material to be used as a filtration test tank is Pyrex glass. We show that an addition of a virus solution 15 min after the beginning of the experiment allows keeping the virus concentration at a high level in the system (including tank, tubing,and pump). No adsorption was observed on membrane materials tested during soaking

Silicon carbide equipments for process intensification of silicon reactions.

Bluestar Silicones, one of the worldwide leaders in silicones chemistry, proposes a R&D project, aiming to design new equipment for the transposition of batch to continuous processes. The safety and environmental issues linked to this type of chemicals, and the productivity targets as well require innovative technologies characterized by a fair corrosion resistance and high heat and mass transfer performances. A preliminary prototype of heat exchanger reactor made of silicon carbide plates has been developed by the LGC in collaboration with a SME specialist of SiC, Boostec. It has allowed the pilot feasibility with some reactions of industrial interest for a Bluestar Silicones to be highlighted. Now, it is necessary to pursue this effort and beyond the feasibility step to go on up to the design of an industrial reactor. This project corresponds to a programme of innovative process development in order to design cleaner, safer and less consuming devices