Distributed Maximum Power Point Tracking: Challenges and Commercial Solutions

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Vibration energy harvester, optimized by electronically emulated mechanical tuning technique

The present invention refers to a resonant vibration energy harvester (1) for optimizing the conversion of vibrational kinetic energy generated by an external source into electrical energy, to a system comprising such resonant vibration energy harvester and to a method for optimizing the conversion of vibrational kinetic energy generated by an external source into electrical energy

Stochastic Thermodynamics of an Electromagnetic Energy Harvester

We study the power extracted by an electromagnetic energy harvester driven by broadband vibrations. We describe the system with a linear model, featuring an underdamped stochastic differential equation for an effective mass in a harmonic potential, coupled electromechanically with the current in the circuit. We compare the characteristic curve (power vs. load resistance) obtained in experiments for several values of the vibration amplitude with the analytical results computed from the model. Then, we focus on a more refined analysis, taking into account the temporal correlations of the current signal and the fluctuations of the extracted power over finite times. We find a very good agreement between the analytical predictions and the experimental data, showing that the linear model with effective parameters can describe the real system, even at the fine level of fluctuations. Our results could be useful in the framework of stochastic thermodynamics applied to energy harvesting systems

Recent advances in the surgical care of breast cancer patients

A tremendous improvement in every aspect of breast cancer management has occurred in the last two decades. Surgeons, once solely interested in the extipartion of the primary tumor, are now faced with the need to incorporate a great deal of information, and to manage increasingly complex tasks

Fast Hybrid MPPT Technique for Photovoltaic Applications: Numerical and Experimental Validation

In PV applications, under mismatching conditions, it is necessary to adopt a maximum power point tracking (MPPT) technique which is able to regulate not only the voltages of the PV modules of the array but also the DC input voltage of the inverter. Such a technique can be considered a hybrid MPPT (HMPPT) technique since it is neither only distributed on the PV modules of the PV array or only centralized at the input of the inverter. In this paper a new HMPPT technique is presented and discussed. Its main advantages are the high MPPT efficiency and the high speed of tracking which are obtained by means of a fast estimate of the optimal values of PV modules voltages and of the input inverter voltage. The new HMPPT technique is compared with simple HMPPT techniques based on the scan of the power versus voltage inverter input characteristic. The theoretical analysis and the results of numerical simulations are widely discussed. Moreover, a laboratory test system, equipped with PV emulators, has been realized and used in order to experimentally validate the proposed technique

Distributed maximum power point tracking with overvoltage protection for pv systems

This paper presents an integral solution of the overvoltage problem caused by mismatched conditions when DC-DC converter outputs of PV systems are connected in series, and a distributed maximum power point tracking architecture is implemented. The operating conditions that cause the overvoltage problem are discussed in detail and the consequences of the overvoltage problem are illustrated. The proposed solution is based on a structure that includes a non-linear controller, two linear controllers, and a maximum power point tracking algorithm. Such a solution makes it possible to regulate the PV voltage according to the MPPT controller commands and to limit the DC-DC converter output voltage to avoid damages. The non-linear control structure is experimentally validated with a boost converter and a BP585 PV panel. Simulation results show that the proposed integral solution allows the operation of PV panels in the feasible maximum power point and protects the integrity of the DC-DC converters, avoiding the overvoltage problem caused by mismatched conditions

Fast Hybrid MPPT Technique for Photovoltaic Applications: Numerical and Experimental Validation

In PV applications, under mismatching conditions, it is necessary to adopt a maximum power point tracking (MPPT) technique which is able to regulate not only the voltages of the PV modules of the array but also the DC input voltage of the inverter. Such a technique can be considered a hybrid MPPT (HMPPT) technique since it is neither only distributed on the PV modules of the PV array or only centralized at the input of the inverter. In this paper a new HMPPT technique is presented and discussed. Its main advantages are the high MPPT efficiency and the high speed of tracking which are obtained by means of a fast estimate of the optimal values of PV modules voltages and of the input inverter voltage. The new HMPPT technique is compared with simple HMPPT techniques based on the scan of the power versus voltage inverter input characteristic. The theoretical analysis and the results of numerical simulations are widely discussed. Moreover, a laboratory test system, equipped with PV emulators, has been realized and used in order to experimentally validate the proposed technique

COVID-19 and Oral Surgery: a narrative review of preoperative mouth rinses

Cilj: Obaviti narativni pregled predloženih preoperativnih protokola za ispiranje usne šupljine prije oralno-kirurških zahvata da bi se u aerosolu suzbila pojavnosti virusa SARS-CoV-2. Izvori: Pretražene su znanstvene baze podataka PubMed, MedLine, CINAHN i Scopus kako bi se pronašli relevantni radovi objavljeni do trećeg tjedna travnja 2020. godine. Ovo istraživanje dopunjeno je pretraživanjem putem internetske tražilice te ručnim pretraživanjem međunarodnih i nacionalnih smjernica. Odabir istraživanja: Uključena su istraživanja i protokoli u kojima se predlaže preoperativno ispiranje usta kao mjera tijekom pandemije virusa COVID-19. S obzirom na to da je dostupan mali broj istraživanja, obavljen je pregled narativne literature. Ukupno se 15 referencija (11 članaka i 4 smjernice) smatralo mjerodavnima i kritički je analizirano. Zaključak: Rezultati pokazuju visoku heterogenost u predloženim protokolima. Potrebna su daljnja istraživanja da bi se bolje razumjele značajke i epidemiološka obilježja novog virusa te da bi se ispitala učinkovitost uobičajenih antiseptika protiv virusa SARS-CoV-2 u budućim kliničkim ispitivanjima. No upotreba klorheksidina, vodikova peroksida, providon-jodida i cetilpiridinijeva klorida, sa svrhom prevencije širenja bolesti uzrokovane virusom COVID-19, u različitim je časopisima opisana kao poželjna.Objective: To provide a narrative review of the preprocedural mouth rinse protocols suggested for oral surgery in order to contrast the presence of SARS-CoV-2 in aerosol. Sources and Methods: Electronic searches were performed in medical databases PubMed, Medline, CINAHN and Scopus to identify relevant studies published up until the third week of April 2020. This research was supplemented by exploration through a web-based search engine as well as a manual search for international and national guidelines. Studies and protocols which suggested preoperative mouth rinsing as a recommended measure during the COVID-19 outbreak were included. Given the small number of studies, a narrative literature review was conducted. In total, 15 references (11 articles and 4 guidelines) were considered relevant and were critically analysed. Conclusion: The findings show a high heterogeneity in the protocols suggested. Further research is required to better understand the viral features and epidemiologic characteristics of this new virus and to test the efficacy of commonly used antiseptics against SARS-CoV-2 in future clinical trials. However, the use of chlorhexidine, hydrogen peroxide, PVP-I and cetylpyridinium chloride in contrasting the spread of Covid-19 is described as advisable and substantial in different publications

Relationship Between Risk Factors and Mortality in Type 1 Diabetic Patients in Europe: The EURODIAB Prospective Complications Study (PCS)

OBJECTIVE—The purpose of this study was to examine risk factors for mortality in patients with type 1 diabetes