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Soft switching characterization of a 6.5kV IGBT for high power LLC resonant DC-DC converter
No full textMedium voltage (MV) high power applications are usually realized using high voltage semiconductors (3.3kV and above) operated in hard switching mode with low switching frequencies (several hundreds of Hz). However, for high power DC-DC converters employing a transformer for galvanic isolation, it is attractive to increase the switching frequency so that the transformer size can be reduced. In this paper, switching properties of 6.5kV IGBT within a DC-DC LLC resonant converter are presented, highlighting interactions between semiconductor and circuit properties, which both must be simultaneously considered in order to achieve the best utilization of a high voltage power semiconductor operating at higher switching frequencies. Experimental results are presented to illustrate characteristic operating conditions.PE
Towards learning-based image compression for storage on DNA support
No full textThe demand for data storage has grown exponentially over the past decades. Current archival solutions have significant shortcomings, such as high resource requirements and a lack of sufficient longevity. In contrast, research on DNA-based storage has been advancing notably due to its low environmental impact, larger capacity, and longer lifespan. This has led to the development of compression methods that adapted the binary representation of legacy JPEG images into a quaternary base of nucleotides while taking into account the biochemical constraints of current synthesis and sequencing mechanisms. In this work, we show that DNA can also be leveraged to efficiently store images compressed with neural networks even without a need for retraining, by combining a convolutional autoencoder with a Goldman encoder. The proposed method is compared to the state of the art, resulting in higher compression efficiency on two different datasets when evaluated by a number of objective quality metrics.GR-E
Solar Detoxification of Water
No full textLBEAbstracts: 4th International Conference Solar Energy Storage and Applied Photochemistry, Cairo, Egypt, January 1-6, 199
Novel Concepts and Recent Progress in Distributed Optical Fiber Sensing
No full textRecent techniques open new perspectives for distributed fiber sensing. Pulse coding and multi-dimensional denoising methods result in a >10 dB noise reduction with minor modifications of the experimental layout.SCI-STI-LTInvited pape
Omnidirectional pulse dispersion of planar circular monopoles
No full textThree antenna systems, composed of circular monopoles with different ground plane sizes, are studied. The transmission of an UWB pulse between two identical monopoles is analyzed. The omnidirectional properties of the UWB antennas are measured and simulated in frequency and time. The System Fidelity Factor of each system is obtained, quantifying the distortion of the received pulses in the azimuth plane. Results show that. the size of the ground plane affects the efficiency of a monopole system when transmitting an UWB pulse.LEMASCI-STI-A
An exergy based approach to determine production cost and CO2 allocation for petroleum derived fuels
No full textThe renewable and non-renewable exergy and CO2 costs of petroleum derived fuels produced in Brazil are evaluated using exergoeconomy to rationally distribute the exergy costs and the CO2 emitted in processes with more than one product. An iterative procedure is used to take into account the cyclic interactions of the processed fuels. The renewable and non-renewable exergy costs together with the CO2 cost provide a reasonable way to compare different fuels and can be used to assess an enormous quantity of processes that make use of petroleum derived products. The system considers Brazilian typical processes and distances: offshore oil and gas production, transportation by shuttle tankers and pipelines, and refining. It was observed that the renewable exergy cost contribution in the total exergy cost of petroleum derived fuels is negligible. On average, the refining process is responsible, for 85% of the total unit exergy cost. Total unit exergy costs of gasoline, liquefied petroleum gas, natural gas and fuel oil were found to be: 1.081 MJ/MJ, 1.074 MJ/MJ, 1.064 MJ/MJ, 1.05 MJ/MJ, respectively. The hydrotreatment process increases diesel cost from 1.038 MJ/MJ to 1.11 MJ/MJ in order to decrease its sulphur content. The CO2 cost reflects the extent of processing as well as the C/H ratio of the used fuel. Hence, coke followed by hydrotreated diesel have the largest CO2 cost among the fuels, 91 gCO2/MJ and 79 gCO2/MJ, respectively.SCI-STI-F
Les bidonvilles en Inde. Un modèle d'habitat alternatif. Cas de Chennai (Madras), Tamil Nadu
No full textAvec près de cent millions d'habitants, les bidonvilles indiens occupent une place importante dans la ville. Ils sont un milieu hybride, entre le monde urbain dans lequel ils se trouvent et le monde rural, origine des habitants. Mais leur statut informel les rend fragiles et sujets à la destruction. Généralement séparés du reste de la ville, l'accès aux infrastructures et à la vie urbaine leur est nié, et les projets de réhabilitation du gouvernement prônent généralement une relocalisation aux limites de la ville dans des complexes sans identité. A travers le cas du Dr. Ambedkar Slum à Chennai (Madras), le projet cherche à proposer une alternative – socialement, économiquement et culturellement – aux destructions actuelles en travaillant sur un développement in situ. Le projet compte permettre le développement du bidonville et son intégration progressive à la ville grâce à sa planification urbaine, l'installation d'infrastructures et la conception d'habitat plus pérenne. Moins radical, il propose une transformation lente et naturelle s'appuyant sur des éléments existants et permettant au bidonville de devenir un quartier urbain avec le temps. Flexible, il cherche à s'adapter à une ville en mutation constante, ainsi qu'aux communautés et modes de vie variés. Le projet est vu comme un processus plus qu'un produit, où l'architecture devient le support d'un message sur la tradition, l'artisanat local et l'économie des moyens, réutilisant des traditions pour construire le présent.SAR-DLACLASURCote: 2014.040Archive: MEM.1/2 A4 horizontal, MEM.2/2 A5 horizontal, CD.1/1Groupe de suivi: Ruzicka-Rossier Monique (dir. pédagogique); Pedrazzini Yves (prof.); Baitsch Tobias (maître EPFL); Mestelan Patrick (expert)Professeur responsable de l'Enoncé: Pedrazzini Yves (ENAC INTER LASUR)Enoncé théorique de master: Les bidonvilles en Inde. Un modèle d'habitat urbain alternatif. Cas de Chennai, Tamil Nadu
System of nano-silver inkjet printed memory cards and PC card reader and programmer
No full textThis work describes the development of inkjet printed, low-cost memory cards, and complementary pair of memory card reader and card reader/programmer for PCs. This constitutes a complete system that can be used for various applications. The memory cards are manufactured by inkjet printing nano-silver ink on photo paper substrate. The printed memory structures have an initial high resistance that can later be programmed to specific values representing data on the cards, the so called Write Once Read Many (WORM) memories. The memory card reader measures the resistance values of the memory cells and reads it back to the computer by USB connection. Using multiple resistance levels that represent different states it is possible to have a larger number of selectable combinations with fewer physical bits compared to binary coding. This somewhat counters one of the limitations of resistive memory technology that basically each cell needs one physical contact. The number of possible states is related to the resolution of the reader and the stability of the WORM memory. (C) 2010 Elsevier Ltd. All rights reserved.NANOLA
Catalytic Oxidation of BTX (Benzene, Toluene, and Xylene) Using Metal Oxide Perovskites
No full textThe high toxicity, volatility, and dispersion of the light aromatics, benzene, toluene, and xylene (BTX) pose a serious threat to the environment and human health. Compared to incineration, catalytic oxidation technologies for BTX removal offer benefits such as low energy consumption, high efficiency, and low pollution. ABO3-type perovskite catalysts (ABO3-PCs) are particularly promising materials for the catalytic oxidation of BTX due to their high activity and thermal stability, as well as their adjustable elemental composition and flexible structure allowing their properties to be improved. Nonetheless, the full potential of ABO3-PCs for the oxidation of BTX has yet to be reached. This review systematically and critically analyses progress in the catalytic oxidation of BTX by ABO3-PCs. Catalytic performance is assessed for each category of perovskite, including non-doped, doped (A-, B-, or A/B-site doped), and loading type (noble metal, metal oxide, and matrix composite), with structure-activity relationships are established. A kinetic model and proposed mechanism for the catalytic oxidation of BTX are also presented. Finally, the challenges and opportunities of ABO3-PCs applied to BTX oxidation and other reactions are highlighted.|The emission of benzene, toluene, and xylene (BTX) compounds poses urgent and substantial threats to both the environment and human health. This review systematically analyses the progress in catalytic oxidation of BTX pollutants using metal oxide perovskites, providing valuable insights into their catalytic performance, mechanisms, and potential applications in real-world scenarios. imageGMFLCO