26 research outputs found

    Enabling technologies for innovative energy management systems in domestic applications

    Get PDF
    Storage systems became one of the most appreciated solution of some problems related with energy distribution and a fundamental part in the new energy system well known as Virtual Power Systems (VPS). A VPS is a new way to manage the energy, starting from production by standard power plants and renewable sources, to consumption in industries and villages. Actually, distributed generation from renewable sources starts creating electric stability problems in the distribution system/network due to the impulsive injection of energy and also for the non-predictable generation profile. For these reasons is absolutely necessary to guarantee a good integration of the new energy sources in the actual power system and storage can become the perfect joining link for the realization of a Smart Grid

    Trade-off analysis and design of a Hydraulic Energy Scavenger

    Get PDF
    In the last years there has been a growing interest in intelligent, autonomous devices for household applications. In the near future this technology will be part of our society; sensing and actuating will be integrated in the environment of our houses by means of energy scavengers and wireless microsystems. These systems will be capable of monitoring the environment, communicating with people and among each other, actuating and supplying themselves independently. This concept is now possible thanks to the low power consumption of electronic devices and accurate design of energy scavengers to harvest energy from the surrounding environment. In principle, an autonomous device comprises three main subsystems: an energy scavenger, an energy storage unit and an operational stage. The energy scavenger is capable of harvesting very small amounts of energy from the surroundings and converting it into electrical energy. This energy can be stored in a small storage unit like a small battery or capacitor, thus being available as a power supply. The operational stage can perform a variety of tasks depending on the application. Inside its application range, this kind of system presents several advantages with respect to regular devices using external energy supplies. They can be simpler to apply as no external connections are needed; they are environmentally friendly and might be economically advantageous in the long term. Furthermore, their autonomous nature permits the application in locations where the local energy grid is not present and allows them to be ‘hidden' in the environment, being independent from interaction with humans. In the present paper an energy-harvesting system used to supply a hydraulic control valve of a heating system for a typical residential application is studied. The system converts the kinetic energy from the water flow inside the pipes of the heating system to power the energy scavenger. The harvesting unit is composed of a hydraulic turbine that converts the kinetic energy of the water flow into rotational motion to drive a small electric generator. The design phases comprise a trade-off analysis to define the most suitable hydraulic turbine and electric generator for the energy scavenger, and an optimization of the components to satisfy the systems specification

    Design and characterization of small thermoelectric generators for environmental monitoring devices

    Get PDF
    A small thermoelectric generator to power autonomous sensors in remote environmental sites is studied, designed, realized, characterized, and tested. The thermoelectric phenomena, applied to our device, are theoretically introduced and experimentally verified by directly measuring the physical quantities when the thermoelectric generator operates in working conditions. The device is then tested under different external conditions, showing that it is able to supply, for sufficient long time, an output voltage higher than 200 mV and an output power on the order of 10 mW when a temperature difference higher than 10 K and a load resistance close to the internal resistance are considered. Furthermore we developed a devoted power conditioning circuit in order to usefully manage the output voltage. Finally, we tested the device in real operative conditions

    A possible common explanation for several cosmic microwave background (CMB) anomalies: A strong impact of nearby galaxies on observed large-scale CMB fluctuations

    Full text link
    In Luparello et al. 2023, a new and hitherto unknown CMB foreground was detected. A systematic decrease in Cosmic Microwave Background (CMB) temperatures around nearby large spiral galaxies points to an unknown interaction with CMB photons in a sphere up to several projected Mpc around these galaxies. We investigate to which extent this foreground may impact the CMB fluctuations map and create the so-called CMB anomalies. Using the observed temperature decrements around the galaxies, and making some general assumptions about the unknown interaction, we propose a common radial temperature profile. By assigning this profile to nearby galaxies in the redshift range z=[0.004,0.02]z=[0.004,0.02] we create a foreground map model. We find a remarkable resemblance between this temperature model map based on nearby galaxies and the Planck CMB map. Out of 1000 simulated maps, none of them show such a strong correlation with the foreground map over both large and small angular scales. In particular, the quadrupole, octopole, as well as =4\ell=4 and =5\ell=5 modes correlate with the foreground map to high significance. Furthermore, one of the most prominent temperature decrements in the foreground map coincides with the position of the CMB cold spot. The largest scales of the CMB and thereby the cosmological parameters, may have important changes after proper corrections of this foreground component. However, a reliable corrected CMB map can only be derived when suitable physical mechanisms are proposed and tested.Comment: 5 pages, 4 figures, revised version which is accepted for publication in A&A Letter

    A novel hybrid MPPT technique for solar PV applications using perturb & observe and fractional open circuit voltage techniques

    Get PDF
    Solar photovoltaic (PV) systems have been an area of active research for the last few decades to improve the efficiency of solar PV module. The non-linear nature of IV curve of solar PV module demands some technique to track the maximum voltage and maximum current point on IV curve corresponding to Maximum Power Point(MPP). Thus, Maximum Power Point Tracking (MPPT) techniques are widely deployed for this purpose. Lot of MPPT techniques have been developed in recent past but still most commercial systems utilizes the perturb & observe (P&O) MPPT technique because of its simple algorithm, low cost and ease of implementation. However, this technique is slow in tracking MPP under rapidly changing irradiance conditions and it also oscillates around the MPP. This paper addresses this problematic behavior of P&O technique and hence presents a novel MPPT hybrid technique that is combination of two basic techniques i.e. P&O and Fractional Open Circuit Voltage (FOCV) technique in order to overcome the inherited deficiencies found in P&O technique. The proposed MPPT technique is much more robust in tracking the MPP even under the frequent changing irradiance conditions and is less oscillatory around the MPP as compared to P&O. The technique is verified using MATLAB/SIMULNK and simulation results show a clear improvement in achieving the MPP when subjected to change in irradianc

    The cosmic shallows I: interaction of CMB photons in extended galaxy halos

    Full text link
    We report and analyse the presence of foregrounds in the cosmic microwave background (CMB) radiation associated to extended galactic halos. Using the cross correlation of Planck and WMAP maps and the 2MRS galaxy catalogue, we find that the mean temperature radial profiles around nearby galaxies at cz4500 km s1cz\le 4500~\rm{km~s^{-1}} show a statistically significant systematic decrease of 15 μK\sim 15~\mu \rm{K} extending up to several galaxy radii. This effect strongly depends on the galaxy morphological type at scales within several tens of times the galaxy size, becoming nearly independent of galaxy morphology at larger scales. The effect is significantly stronger for the more extended galaxies, with galaxy clustering having a large impact on the results. Our findings indicate the presence of statistically relevant foregrounds in the CMB maps that should be considered in detailed cosmological studies. Besides, we argue that these can be used to explore the intergalactic medium surrounding bright late-type galaxies and allow for diverse astrophysical analyses.Comment: 10 pages, 9 figures, submitted to MNRA

    Enhancement of the medial olivocochlear system prevents hidden hearing loss

    Get PDF
    Cochlear synaptopathy produced by exposure to noise levels that cause only transient auditory threshold elevations is a condition that affects many people and is believed to contribute to poor speech discrimination in noisy environments. These functional deficits in hearing, without changes in sensitivity, have been called hidden hearing loss (HHL). It has been proposed that activity of the medial olivocochlear (MOC) system can ameliorate acoustic trauma effects. Here we explore the role of the MOC system in HHL by comparing the performance of two different mouse models: an α9 nicotinic receptor subunit knock-out (KO; Chrna9 KO), which lacks cholinergic transmission between efferent neurons and hair cells; and a gain-of-function knock-in (KI; Chrna9L9′T KI) carrying an α9 point mutation that leads to enhanced cholinergic activity. Animals of either sex were exposed to sound pressure levels that in wild-type produced transient cochlear threshold shifts and a decrease in neural response amplitudes, together with the loss of ribbon synapses, which is indicative of cochlear synaptopathy. Moreover, a reduction in the number of efferent contacts to outer hair cells was observed. In Chrna9 KO ears, noise exposure produced permanent auditory threshold elevations together with cochlear synaptopathy. In contrast, the Chrna9L9′T KI was completely resistant to the same acoustic exposure protocol. These results show a positive correlation between the degree of HHL prevention and the level of cholinergic activity. Notably, enhancement of the MOC feedback promoted new afferent synapse formation, suggesting that it can trigger cellular and molecular mechanisms to protect and/or repair the inner ear sensory epithelium.Fil: Boero, Luis Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Castagna, Valeria Carolina. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Di Guilmi, Mariano Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Goutman, Juan Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Elgoyhen, Ana Belen. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Gomez Casati, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentin

    Functional Status in Older Adults following Hospitalization for COVID-19: A Cohort Study

    Get PDF
    Background Coronavirus disease 2019 (COVID-19) can cause multiple acute complications. This study evaluated the long-term functional status of older patients hospitalized for acute COVID-19. Methods We analyzed data from a multicenter ambispective cohort study on patients aged >60 years who were hospitalized for COVID-19 at two tertiary care hospitals in Argentina. The participants were contacted by telephone between November 2021 and September 2022 to collect data on their functional status. Ordinal logistic regression was used to identify factors associated with functional limitations after discharge. Results Among the 374 included patients, 205 (55%) showed functional limitations, including 58 (28%) who died during follow-up. The factors independently associated with functional limitations were low baseline functional status (odds ratio [OR]=9.19; 95% confidence interval [CI], 3.35–25.17) and admission to the intensive care unit (OR=4.41; 95% CI, 2.28–8.53). Men had lower odds of functional impairment (OR=0.55; 95% CI, 0.35–0.86). Conclusion Older patients had high mortality rates and poor functional status at 2 years post-discharge for COVID-19. Several factors at the time of discharge were associated with a higher risk of functional limitations and can be used to identify patients’ long-term needs for support and rehabilitation services

    Diagnóstico serológico de brucelosis en perros del conurbano sur bonaerense

    Get PDF
    El objetivo del presente trabajo fue determinar la seroprevalencia de brucelosis canina por aglutinación rápida (RSAT) en caninos provenientes de la zona sur del gran Buenos Aires y evaluar la presencia de anticuerpos contra cepas lisas de Brucella en la misma población.Facultad de Ciencias Veterinaria

    Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology

    Get PDF
    A cross-ancestry genome-wide association meta-analysis of amyotrophic lateral sclerosis (ALS) including 29,612 patients with ALS and 122,656 controls identifies 15 risk loci with distinct genetic architectures and neuron-specific biology. Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a lifetime risk of one in 350 people and an unmet need for disease-modifying therapies. We conducted a cross-ancestry genome-wide association study (GWAS) including 29,612 patients with ALS and 122,656 controls, which identified 15 risk loci. When combined with 8,953 individuals with whole-genome sequencing (6,538 patients, 2,415 controls) and a large cortex-derived expression quantitative trait locus (eQTL) dataset (MetaBrain), analyses revealed locus-specific genetic architectures in which we prioritized genes either through rare variants, short tandem repeats or regulatory effects. ALS-associated risk loci were shared with multiple traits within the neurodegenerative spectrum but with distinct enrichment patterns across brain regions and cell types. Of the environmental and lifestyle risk factors obtained from the literature, Mendelian randomization analyses indicated a causal role for high cholesterol levels. The combination of all ALS-associated signals reveals a role for perturbations in vesicle-mediated transport and autophagy and provides evidence for cell-autonomous disease initiation in glutamatergic neurons
    corecore