A QFD framework for quality, innovation and high-tech product development dynamics

The customer mostly chooses a product on the base of its quality, which therefore arises as the main cause of its commercial success. In a nearly axiomatic drawing, it follows that the effect of innovation is the improvement of quality, which itself becomes the aim of innovation. Even though the previous statement relates quality and innovation, it still does not explain their dynamics. To stress them, the ‘quality' concept must be analyzed in more detail. In fact, in addition to the ‘perceived quality', the quality ensured through `design, manufacturing and marketing' combined domains should be dealt with. This paper enhances this issue taking advantage of principles and models made available by control theory schemes coupled with quality function development (QFD) and best practice software modeling based on unified modeling language (UML

Single-Phase Grid Connected Converters for Photovoltaic Plants

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Analysis of Voltage Distribution and Connections within a High-Frequency Hairpin Winding Model

In the last years the adoption of hairpin windings is increasing, especially in the automotive sector, mainly due to their inherently high fill factor and electric loading capability. A critical aspect related to the reliability and lifetime of every winding typology is the voltage stress due to the uneven voltage distribution. This phenomenon has already been largely analyzed in conventional stranded conductors, while a few studies are available for hairpin windings. With the spreading of wide bandgap devices, the investigation on voltage distribution becomes an ever-timely topic due to their short rise times. This paper presents an analysis of the uneven voltage distribution triggered within hairpin windings by a low rise time waveform, using a complete high-frequency winding model. The different options to series-connect different paths are investigated, providing simple but essential guidelines to reduce the electrical stress within hairpin windings. © 20XX IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThis paper reflects only the author's view. JU is not responsible for any use that may be made of the information it contains

Epidemiology and Prevention of Early Infections by Multi-Drug-Resistant Organisms in Adults Undergoing Liver Transplant: A Narrative Review

Invasive bacterial infections are a leading cause of morbidity and mortality after liver transplant (LT), especially during the first months after LT, and infections due to multi-drug-resistant organisms (MDRO) are increasing in this setting. Most of the infections in patients in intensive care unit arise from the endogenous microflora and, for this reason, pre-LT MDRO rectal colonization is a risk factor for developing MDRO infections in the post-LT. Moreover, the transplanted liver may carry an increased risk of MDRO infections due to organ transportation and preservation, to donor intensive care unit stay and previous antibiotic exposure. To date, little evidence is available about how MDRO pre-LT colonization in donors and recipients should address LT preventive and antibiotic prophylactic strategies, in order to reduce MDRO infections in the post-LT period. The present review provided an extensive overview of the recent literature on these topics, with the aim to offer a comprehensive insight about the epidemiology of MDRO colonization and infections in adult LT recipients, donor-derived MDRO infections, possible surveillance, and prophylactic strategies to reduce post-LT MDRO infections

Epidemiology of enuresis: a large number of children at risk of low regard

Aim: To describe the epidemiological aspects of nocturnal enuresis (NE). In this study we identify the prevalence and the familial conditions in a large, representative sample of children with monosymptomatic NE (MNE) and nonmonosyptomatic NE (NMNE). Material and methods: In this descriptive-analytic study the Italian Society of Pediatrics (SIP) promoted a prevalence study of NE using a questionnaire involved 320 primary care Pediatricians from Northern, Central and Southern Italy, from January 2019 to July 2019, with a total of 130,000 children analyzed by questionnaire related to epidemiology and type of NE, familiarity, quality of sleep, eating and drinking habits, pharmacological and psychological/behavioural interventions and family involvement. Results: 270/320 (84.4%) Paediatrician replied to our questionnaire. We enrolled a total of 9307/130,000 (7.2%) children with NE, aged between 5 and 14 years: 2141 diagnosed with MNE and 7176 qualified as NMNE. Poor quality of sleep were reported in 7064 patients; 90% of children did not consider a dietary and drinking recommendation. Pediatrician reported a total of 54.1% of parents who declared to have a negative reaction to their children because of the bedwetting. A percentage of 71.4% of parents declared to use or to have used alternative therapies and not to prefer, at first, a pharmacological intervention. Conclusion: The choice of treatment should include psychological/behavioural interventions in all cases to improve the therapeutic outcome. All primary care Pediatricians should be aware of the all aspects of NE to choose the best way to treat every patient

Early-Type Galaxies in the Hubble Deep Field: The Star Formation History

We have investigated the properties of a complete K-band selected sample of 35 elliptical and S0 galaxies brighter than K=20.15 in the Hubble Deep Field, as representative of the field galaxy population. This sample has been derived from deep K-band image by the KPNO-IRIM camera, by applying a rigorous morphological classification scheme based on quantitative analyses of the surface brightness profiles. The broad-band spectra of the sample galaxies allow us to date their dominant stellar populations. The majority of bright early-types in this field are found at redshifts z<1.3 to display colors indicative of a fairly wide range of ages (typically 1.5 to 3 Gyrs). We find that the major episodes of star-formation building up typical M_star galaxies have taken place during a wide redshift interval 11.3, which should be detectable during the luminous star-formation phase expected to happen at these redshifts. Obvious solutions are a) that the merging events imply perturbed morphologies which prevent selecting them by our morphological classification filter, or b) that a dust-polluted ISM obscures the (either continuous or episodic) events of star-formation. We conclude that the likely solution is a combination thereof, i.e. a set of dust-enshrouded merging-driven starbursts occurring during the first few Gyrs of the galaxy's lifetime

A frailty index predicts post-liver transplant morbidity and mortality in HIV-positive patients

Background: We hypothesized that frailty acts as a measure of health outcomes in the context of LT. The aim of this study was to explore frailty index across LT, as a measure of morbidity and mortality. This was a retrospective observational study including all consecutive 47 HIV+patients who received LT in Modena, Italy from 2003 to June 2015. Methods: frailty index (FI) was constructed from 30 health variables. It was used both as a continuous score and as a categorical variable, defining 'most frail' a FI > 0.45. FI change across transplant (deltaFI, \uce\u94FI) was calculated as the difference between year 1 FI (FI-Y1) and pre-transplant FI (FI-t0). The outcomes measures were mortality and "otpimal LT" (defined as being alive without multi-morbidity). Results: Median value of FI-t0 was 0.48 (IQR 0.42-0.52), FI-Y1 was 0.31 (IQR 0.26-0.41). At year five mortality rate was 45%, "optimal transplant" rate at year 1 was 38%. All the patients who died in the post-LT were most frail in the pre-LT. \uce\u94FI was a predictor of mortality after correction for age and MELD (HR = 1.10, p = 0.006) and was inversely associated with optimal transplant after correction for age (HR = 1.04, p = 0.01). Conclusions: We validated FI as a valuable health measure in HIV transplant. In particular, we found a relevant correlation between FI strata at baseline and mortality and a statistically significant correlation between, \uce\u94FI and survival rate

Partial Discharges in Electrical Machines for the More Electric Aircraft—Part I: A Comprehensive Modeling Tool for the Characterization of Electric Drives Based on Fast Switching Semiconductors

This paper proposed a modelling approach for the comprehensive analysis of high-frequency challenges in electrical drives designed for aerospace applications, in particular the overvoltage at the machine terminals and the voltage distribution within windings. After a separate description of the models for the estimation of these insulation stress sources, the combined model was detailed. The main benefit of developing a combined, flexible and comprehensive tool is that both overvoltage at machine terminals and uneven voltage distribution can be calculated simultaneously, without neglecting the voltage overshoot when estimating the voltage distribution (and vice versa). In fact, an accurate calculation of the terminal overvoltage is necessary to provide a good estimation of the voltage within winding turns since its waveform shape can be quite different with respect to the converter output, even with cables of a few meters. A case study based on a real aerospace application was considered to investigate the model validity and accuracy. Experimental results were performed on a complete system comprising a SiC-based converter, a connecting cable and a machine stator, proving the simulation model accuracy in terms of peak voltages of both the line-to-line terminal voltage and the turn voltage distribution across the first turns, which are the most relevant quantities for the sake of this study as well as for the investigations of the subsequent companion papers. In the forthcoming papers, the effects of different rise times and cable lengths on the inception of partial discharges will be investigated through fast parametric simulation carried out using the proposed combined model. The feasibility of using conventional insulation systems for aircraft applications using SiC drives fed by a ±270 V DC bus voltage will be discussed, with the aim of signaling and finding solutions to improve the overall reliability

Deep HST imaging surveys and the formation of spheroidal galaxies

We have extended our previous analysis of morphologically selected elliptical and S0 galaxies in the Hubble Deep Field (HDF) North to include HST data in the HDF South and the HDFS-NICMOS areas. Our final sample amounts to 69 E/S0 galaxies with $K<20.15$ over an area of 11 square arcmins. Although a moderately small number over a modest sky area, this sample benefits of the best imaging and photometric data available on high-redshift galaxies. Multi-waveband photometry allows us to estimate with good accuracy the redshifts for the majority of these galaxies which lack a spectroscopic measure. We confirm our previous findings that massive E/S0s tend to disappear from flux-limited samples at $z>1.4$. This adds to the evidence that the rest-frame colours and SEDs of the numerous objects found at $0.8<z<1.2$ are inconsistent with a very high redshift of formation for the bulk of stars, while they are better consistent with protracted (either continuous or episodic) star-formation down to $z \le 1$. These results based on high-quality imaging on a small field can be complemented with data from colour-selected EROs on much larger sky areas: our claimed demise of E/S0s going from $z=1$ to $z=1.5$ is paralleled by a similarly fast decrease in the areal density of EROs when the colour limit is changed from $(R-K)=5$ to $(R-K)=6$ (corresponding to $z\simeq 1$ and $z\simeq 1.3$ respectively). Altogether, the redshift interval from 1 to 2 seems to correspond to a very active phase for the assembly of massive E/S0 galaxies in the field, and also probably one where a substantial fraction of their stars are formed.Comment: 9 pages, 7 figures -- Version accepted by MNRA

Frequency-based control of a micro-grid with multiple renewable energy sources

Stand-alone micro-grids need a proper management of the active power exchange. This work is focused on the parallel operation of multiple grid-connected converters in an island-grid system. The proposed solution features a master inverter which emulates the grid and multiple grid-connected converters operating in parallel. The current sharing and overload protection is achieved by small frequency variations of master inverter's output, that are detected by the grid-connected converters. This mechanism exploits the behavior of the derating characteristics embedded in grid-connected inverters, that must reduce the output power if the grid frequency increases. In this case, standard grid-connected equipment can be used to realize micro-grids without the need of digital communication between the power units. Two possible scenarios are analyzed: low-power microgrid with master/slave converters, and low voltage grid fed by a Smart Transformer (ST) which performs the frequency control