Repetitive control for high-performance resonant pulsed power supply in radio frequency applications

This paper presents a novel three phase series resonant parallel loaded (SRPL) resonant converter topology for radio frequency (RF) applications. The proposed converter is capable to produce as output voltage a series of “long pulses”, each one lasting 1ms in time. Three individual single phase resonant stages are able to operate independently in conjunction with three separate single phase output rectification stages. Due to this important feature, the converter has a strong ability of rejecting the influence of unbalance in the resonant tanks. A PI + Repetitive Control (RC) strategy has been used for the output pulsed voltage regulation, resulting in a fast rise time, reduced overshoot, and constant amplitude. The soft-switching of semiconductor devices is ensured at full power by a combined frequency and phase shift modulation (CFPS), even in the presence of large tank unbalances

Resonant–Repetitive combined control for stand-alone power supply unit

This paper investigates a combined resonant–repetitive (RR) control structure for a three-phase four-leg DC/AC converter power supply. The RR control configuration is com-posed by a resonant controller tuned at the system fundamental frequency working in conjunction with a plug-in-type repetitive controller. The resonant part of the control scheme is used to as-sure prompt tracking of the inverter output voltage and to achieve as fast as possible system response to load variations; to this pur-pose, it is tuned at the fundamental frequency. At the same time,the resonant controller is able to stabilize the system without the necessity of any further additional controller; the repetitive part of the scheme is implemented for the fine regulation at the system harmonic frequencies. The proposed control configuration is used to regulate the power supply output voltage, providing very good tracking of the output voltage reference even in the presence of anon linear load. Experimental validation from a 40-kVA converter prototype is presented to validate the operation of the proposed converter and control

Load-adaptive zero-phase-shift direct repetitive control for stand-alone four-leg VSI

This paper deals with a dedicated load adaptive phase compensation algorithm to be used in Repetitive Control based stand-alone 4-leg VSI. The plant model is achieved, its inherent modifications according to the operating point are highlighted and used to properly adapt the Repetitive Control structure. Modification of the repetitive control parameters is described to obtain the desired phase compensation capabilities achieving a Zero-Phase-Shift condition at each harmonic. This allows to increase the gain of the Repetitive Controller at high order harmonics thus yielding a better VSI output voltages with strongly reduced THD and faster dynamic response. As a consequence, the VSI output voltages are almost independent from the loads to be fed and the 4-leg VSI with the proposed Zero-Phase-Shift Direct Repetitive Control is an ideal candidate to supply sensitive loads in microgrid, in particular for stand-alone applications

A Holocene tephra layer within coastal aeolian deposits north of Caleta Olivia (Santa Cruz Province, Argentina)

In this paper we illustrate the stratigraphy, geochronology, and geochemistry (major, minor, trace elements and Sr-isotopes) of a Holocene tephra layer found within coastal sedimentary deposits north of Caleta Olivia (Santa Cruz Province, Argentina). The stratigraphic succession comprises beach deposits with basal erosive surface resting on the local substrate (“Formación Patagonia”) followed by a poorly developed paleosoil. The paleosoil is covered by a lenticular fine grained (Mdφ: 5.2, 0.027 mm), well sorted (σφ: 1.2) volcanic ash layer and aeolian sands. The geochemical composition of shard fragments points to an origin from the Hudson volcano, located in the southern Andes, ca. 400 km to the west. The geochemistry, Sr-isotopes and the radiometric constraints (younger than the age of the underlying marine layer dated at ca. 4,100 a cal BP) further allow correlating this tephra with the so-called H2 eruption (ca. 3,900 a cal BP). This finding is of interest owing to the poor preservation potential of tephra within the Late Holocene sedimentary deposits of the Atlantic coast of Patagonia and represents the first finding of H2 eruption in this area, improving our knowledge of the dispersion of the fine-grained distal deposit of the Hudson volcanic explosive activity, thus allowing a better estimate of the eruptive dynamics and the risks associated with the Hudson volcano

Colloidal fibers as structurant for worm-like micellar solutions

We investigate the rheological properties of a simplified version of a liquid detergent composed of an aqueous solution of the linear alkylbenzene sulphonate (LAS) surfactant, in which a small amount of fibers made of hydrogenated castor oil (HCO) is dispersed. At the concentration typically used in detergents, LAS is in a worm-like micellar phase exhibiting a Maxwellian behavior. The presence of HCO fibers provides elastic properties, such that the system behaves as a simple Zener body, mechanically characterized by a parallel connection of a spring and a Maxwell element. Despite this apparent independence of the contributions of the fibers and the surfactant medium to the mechanical characteristics of the system, we find that the low frequency modulus increases with increasing LAS concentration. This indicates that LAS induces attractive interactions among the HCO fibers, resulting in the formation of a stress-bearing structure that withstands shear at HCO concentrations, where the HCO fibers in the absence of attractive interactions would not sufficiently overlap to provide stress-bearing properties to the system

Niveles altos del mar durante el Último Máximo Interglacial deducidos mediante muescas de abrasión y márgenes internos de terrazas marinas en Puerto Deseado, Provincia de Santa Cruz, Argentina

A detailed geomorphological survey was undertaken in the area of Puerto Deseado (Santa Cruz Province, Argentina) to reconstruct the Relative Sea-level (RSL) position during the Last Interglacial highstand. The presence of active and well-preserved abrasive notches and inner margins of terraces related to the MIS5e and to the Holocene, measured with DGPS, allowed to accurately estimate the RSL change from the present to the MIS5e highstand at ca. 21 m. The geomorphological and geochronological analyses support the notion of the presence of a significant regional tectonic uplift in the Atlantic Patagonia, which can be locally estimated at ca. 0.12 mm/yr.Se realizó un estudio geomorfológico detallado en la zona de Puerto Deseado (provincia de Santa Cruz, Argentina) para reconstruir la posición relativa del nivel (RNM) del mar durante el Último Máximo Interglacial. La presencia de muescas de abrasión activas y bien conservadas, y la posición de los márgenes internos de las terrazas relacionadas con el MIS5e y el Holoceno, medido con GPS diferencial, permitió estimar con precisión el cambio RNM desde el presente hasta la transgresión MIS5e en aproximadamente 21 m. Los análisis geomorfológicos y geocronológicos sustentan la noción de la presencia de un significativo levantamiento tectónico regional en la Patagonia Atlántica, que puede estimarse localmente en alrededor de 0,12 mm/año.Facultad de Ciencias Naturales y Muse

Mid-Holocene relative sea-level changes along Atlantic Patagonia: new data from Camarones, Chubut, Argentina

This paper concerns the relative sea-level changes associated with the Atlantic Patagonian coast derived from sea-level index points whose elevation was determined by a differential global position system (DGPS). Bio encrustations from outcrops located near Camarones, Chubut, Argentina, consist of autochthonous deposits characterized by Austromegabalanus psittacus (Molina, 1782), encrusting acer vulinid foraminifera, coralline red algae and bryozoans. The association of the different organisms is interpreted as being associated with an intertidal environment, and they have been used as index points to establish the relative sea-level position. The main conclusion is that the relative sea-level between c. 7000 and 5300 cal. yr BP was in the range ofc. 2?4 m a.s.l., with a mean value of c. 3.5 m a.s.l. Our data seem to support the existence of different rates of relative sea-level fall in different sectors of Atlantic Patagonia during the Holocene and highlight the importance of a more precise and accurate relative sea-level estimation by producing new data and revisiting the indicative meaning of most of the indicators so far used in the area.Facultad de Ciencias Naturales y Muse

A self-repair history: compensatory effect of a de novo variant on the FANCA c.2778+83C>G splicing mutation

Introduction: Fanconi anemia (FA) is a genome instability condition that drives somatic mosaicism in up to 25% of all patients, a phenomenon now acknowledged as a good prognostic factor. Herein, we describe the case of P1, a FA proband carrying a splicing variant, molecularly compensated by a de novo insertion. Methods and Results: Targeted next-generation sequencing on P1's peripheral blood DNA detected the known FANCA c.2778 + 83C > G intronic mutation and suggested the presence of a large deletion on the other allele, which was then assessed by MLPA and RT-PCR. To determine the c.2778 + 83C > G splicing effect, we performed a RT-PCR on P1's lymphoblastoid cell line (LCL) and on the LCL of another patient (P2) carrying the same variant. Although we confirmed the expected alternative spliced form with a partial intronic retention in P2, we detected no aberrant products in P1's sample. Sequencing of P1's LCL DNA allowed identification of the de novo c.2778 + 86insT variant, predicted to compensate 2778 + 83C > G impact. Albeit not found in P1's bone marrow (BM) DNA, c.2778 + 86insT was detected in a second P1's LCL established afterward, suggesting its occurrence at a low level in vivo. Minigene assay recapitulated the c.2778 + 83C > G effect on splicing and the compensatory role of c.2778 + 86insT in re-establishing the physiological mechanism. Accordingly, P1's LCL under mitomycin C selection preserved the FA pathway activity in terms of FANCD2 monoubiquitination and cell survival. Discussion: Our findings prove the role of c.2778 + 86insT as a second-site variant capable of rescuing c.2778 + 83C > G pathogenicity in vitro, which might contribute to a slow hematopoietic deterioration and a mild hematologic evolution

Fucino palaeo-lake: Towards the Palaeoenvironmental history of the last 430 Ka

© 2010 AIQUA - Associazione Italiana per lo Studio del Quaternario e EMMEVI - Servizio Congressi SPA. The sedimentary succession deposited in Fucino palaeo-lake potentially records the environmental history of the Central Mediterranean Region continuously since the early Pleistocene and up to recent historical times. Fucino palaeo-lake sediments are interbedded with numerous volcanic ash layers which allow the reconstruction a robust and independent chronological framework of past environment changes. This framework is a fundamental tool to synchronise different archives at a regional and extra-regional scale and to better understand the spatio-temporal climate variability in the Quaternary at the orbital and millennial-scales. Here we present new preliminary data for the last five glacial to interglacial cycles