Search results for "SCAD"
showing 10 items of 348 documents
ChemInform Abstract: A Light-Induced Vinylogous Nazarov-Type Cyclization.
2016
The title reaction is incorporated in a three-step cascade transformation providing novel tetracyclic ring structures containing a seven-membered ring.
Cascaded H-Bridges Multielvel Inverters: grid connected advanced applications
Power electronics is going to increase in the modern electrical systems. It is well known that the use of power electronics allows the management and the control of the energy flow, obtaining voltage and current waveforms suitable for electrical loads. In this scenario, multilevel power converters are finding increased attention in industry and academia as one of the promising choices of electronic conversion thanks to their features and many different application fields with high power and medium voltage. Moreover, they are fundamental in interfacing electric grid to high power renewable energy systems (i.e. PV, Wind farm, Biomass, Fuel Cell etc.). Nowadays, the research is focused on the …
A novel method for harmonic mitigation for single-phase five-level cascaded H-Bridge inverter
2018
The efficiency of a system is a very important parameter for high power electrical drives applications. Moreover, the efficiency of power converters plays a fundamental role. Aim of this work, is to propose a novel selective harmonic mitigation method without solving non-linear equations. Through a very simple approach, the polynomial equations which drive the control angles have been detected for a single-phase five-level cascaded H-Bridge inverter. The obtained polynomial equations can be easily implemented in a digital system to real-time operation. The paper also presents the simulation analysis and experimental validation.
Enhanced Modelling for Extended Performance Analysis of Interior Permanent Magnet Synchronous Machine Drive fed with Cascaded H-Bridges Multilevel In…
2021
This paper presents a comparative simulation analysis of an Interior Permanent Magnet Synchronous Machine (IPMSM) performance once fed by a traditional three-phase two-level inverter and then using a three-phase five-level Cascaded H-Bridges Multilevel Inverter (CHBMI). For this purpose, an enhanced mathematical model of the IPMSM, that take into account simultaneously saturation, cross-coupling, spatial harmonics and iron loss effects, has been employed. Furthermore, two different PWM modulation strategies have been considered. The study was conducted for several working conditions, evaluating the impact of CHBMI adoption on the IPMSM performance in terms of improved efficiency and torque …
Conversion of levulinic acid to γ-valerolactone over Zr-containing metal-organic frameworks: Evidencing the role of Lewis and Brønsted acid sites
2021
Zr-containing UiO-66 and MOF-808 are evaluated for converting levulinic acid (LA) into γ-valerolactone (GVL) through various routes: (i) Step-wise esterification of LA to n-butyl levulinate (nBuL) and Meerwein-Ponndorf-Verley (MPV) reduction to GVL; (ii) One-pot two-steps esterification with n-butanol followed by MPV reduction with sec-butanol; and (iii) direct conversion of LA into GVL through a tandem reaction. Selection of this multistep complex reaction evidences the participation of the different acid sites (Lewis or Brønsted) of the material in each individual step: Brønsted-induced acid sites catalyze esterification reaction efficiently, while Lewis acid sites are the preferred sites…
Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory.
2012
The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna s…
IMPLICACIONES DEL USO DE BUSCADORES EN EL COMPORTAMIENTO DE COMPRA ONLINE / IMPLICATIONS OF THE SEARCH ENGINES USE IN THE ONLINE SHOPPING BEHAVIOUR
2009
El objetivo del presente trabajo es analizar los factores que influyen en el uso de buscadores y su incidencia en el comportamiento de compra en Internet. El análisis de resultados obtenidos a partir de una muestra representativa de 485 compradores por Internet españoles, pone de manifiesto que los consumidores que consideran la comodidad, reducciones de precio y amplitud de surtido como motivaciones relevantes para realizar compras online presentan una mayor predisposición al uso de buscadores en la realización de sus compras virtuales. La experiencia como internauta y como comprador en Internet son factores que influyen negativamente en el uso de buscadores para la realización de compras …
Performance Evaluation of a Three- Phase Five-Level Quasi-Z-Source Cascaded H-Bridge for Grid-Connected Applications
2018
In the field of the PV generation, Quasi-Z-source cascaded H-bridge (qZS-CHB) inverters are promising due to their features of modularity and high voltage conversion ratio. Thus, new topology structures and innovative modulation techniques are continuously being developed to improve the performance in terms of voltage stress and harmonic content. This paper proposes an innovative modulation technique that allows reducing the voltage stress and a specially designed grid-connected control strategy is also introduced. Through simulations in MATLAB, it has been validated that the performance of a three-phase five-level qZS-CHB is improved with the proposed solution.
A Novel Symmetrical Boost Modulation Method for qZS-based CHB Inverters
2020
Quasi-Z-source cascaded H-bridge (qZS-CHB) inverters are arising as an innovation in the field of the electrical conversion for PV applications. This type of converters inherit the advantages of multilevel inverters and single-stage configuration. In this context, this paper proposes a novel symmetrical boost modulation strategy for qZS CHB multilevel inverters to increase the performance in terms of voltage stresses and power quality. The novelty lies in the adoption of a different concept to generate the shoot-through states compared to the traditional methods. Simulation analysis in a grid connected application to evaluate the benefits of this boost method is performed in the MATLAB/PLEC…
Concept and setup for intraoperative imaging of tumorous tissue via Attenuated Total Reflection spectrosocopy with Quantum Cascade Lasers
2015
A major challenge in tumor surgery is the differentiation between normal and malignant tissue. Since an incompletely resected tumor easily leads to recidivism, the gold standard is to remove malignant tissue with a sufficient safety margin and send it to pathology for examination with patho-histological techniques (rapid section diagnosis). This approach, however, exhibits several disadvantages: The removal of additional tissue (safety margin) means additional stress to the patient; the correct interpretation of proper tumor excision relies on the pathologist’s experience and the waiting time between resection and pathological result can be more than 45 minutes. This last aspect implies unn…