Experimental Validation of a Novel Magnetorheological Damper with Internal Pressure Control

In the present article, we have investigated the behaviour of magnetorheological fluids under a hydrostatic pressure of up to 40 bar.We have designed, manufactured and tested a magnetorheological damper with a novel architecture, which provides the control of the internal pressure. The pressurewas regulated by means of an additional apparatus connected to the damper that acts on the fluid volume. The magnetorheological damper was tested under sinusoidal inputs and with several values for the magnetic field and internal pressure. The results show that the new architecture is able to work without a volume compensator and bear high pressures. On the one hand, the influence of the hydrostatic pressure on the yield stress of the magnetorheological fluids is not strong, probably because the ferromagnetic particles cannot arrange themselves into thicker columns. On the other hand, the benefits of the pressure on the behaviour of the magnetorheological damper are useful in terms of preventing cavitation

Characterization Of Commercial Magnetorheological Fluids At High Shear Rate: Influence Of The Gap

This paper reports the experimental tests on the behaviour of a commercial MR fluid at high shear rates and the effect of the gap. Three gaps were considered at multiple magnetic fields and shear rates. From an extended set of almost two hundred experimental flow curves, a set of parameters for the apparent viscosity are retrieved by using the Ostwald de Waele model for non-Newtonian fluids. It is possible to simplify the parameter correlation by making the following considerations: the consistency of the model depends only on the magnetic field, the flow index depends on the fluid type and the gap shows an important effect only at null or very low magnetic fields. This lead to a simple and useful model, especially in the design phase of a MR based product. During the off state, with no applied field, it is possible to use a standard viscous model. During the active state, with high magnetic field, a strong non-Newtonian nature becomes prevalent over the viscous one even at very high shear rate; the magnetic field dominates the apparent viscosity change, while the gap does not play any relevant role on the system behaviour. This simple assumption allows the designer to dimension the gap only considering the non-active state, as in standard viscous systems, and taking into account only the magnetic effect in the active state, where the gap does not change the proposed fluid model

Progettazione di uno smorzatore a fluido magnetoreologico con controllo della pressione

Il presente lavoro riguarda la progettazione di uno smorzatore a fluido magnetoreologico (MR) che prevede la possibilità di controllarne la pressione interna. Precedenti studi degli autori, hanno evidenziato che la tensione di primo distacco τB di un fluido MR aumenta in funzione non solo dell'intensità del campo magnetico, ma anche della pressione alla quale si trova. Poiché l'aumento del campo magnetico è limitato da considerazioni quali la potenza dissipata e la saturazione magnetica, regolare in maniera attiva la pressione, consente di potenziare le prestazioni di tali sistemi in modo semplice ed efficiente. Il lavoro descrive la progettazione di dettaglio delle principali funzionalità del sistema: dimensionamento del circuito magnetico, progettazione del sistema idraulico e sviluppo del sistema di controllo della pressione. L’approccio è prevalentemente analitico, al fine di fornire le equazioni necessarie per un dimensionamento di massima del sistema. La metodologia sviluppata fornisce una traccia per un corretto approccio alla progettazione di un sistema smorzante a fluido MR sulla base delle caratteristiche di forza e corsa desiderate e degli ingombri disponibili

Design of a novel magnetorheological damper with internal pressure control

In this work we designed and manufactured a novel magnetorheological (MR) fluid damper with internal pressure control. Previous authors’ works showed that the yield stress ?B of MR fluids depends both on the magnetic field intensity and on the working pressure. Since the increase of the magnetic field intensity is limited by considerations like power consumption and magnetic saturation, an active pressure control leads to a simple and efficient enhancement of the performances of these systems. There are three main design topics covered in this paper about the MR damper design. First, the design of the magnetic circuit; second the design of the hydraulic system and third the development of an innovative pressure control apparatus. The design approach adopted is mainly analytical and provides the equations needed for system design, taking into account the desired force and stroke as well as the maximum external dimensions

Design of a novel magnetorheological damper with internal pressure control

In this work we designed and manufactured a novel magnetorheological (MR) fluid damper with internal pressure control. Previous authors’ works showed that the yield stress ?B of MR fluids depends both on the magnetic field intensity and on the working pressure. Since the increase of the magnetic field intensity is limited by considerations like power consumption and magnetic saturation, an active pressure control leads to a simple and efficient enhancement of the performances of these systems. There are three main design topics covered in this paper about the MR damper design. First, the design of the magnetic circuit; second the design of the hydraulic system and third the development of an innovative pressure control apparatus. The design approach adopted is mainly analytical and provides the equations needed for system design, taking into account the desired force and stroke as well as the maximum external dimensions

Regional and sex inequalities of avoidable mortality in Italy: A time trend analysis

Objectives: This study provides a comprehensive analysis of avoidable mortality (AM), treatable mortality (TM), and preventable mortality (PM) across Italy, focusing on region- and gender-specific inequalities over a 14-year period. Study design: Time-trend analysis (2006–2019). Methods: The study was conducted using mortality data from the Italian Institute of Statistics to evaluate the extent and patterns of AM, TM, and PM in Italy. Biennial age-standardized mortality rates were calculated by gender and region using the joint OECD/Eurostat list. Results: The overall AM rates showed a large reduction from 2006/7 (221.0 per 100,000) to 2018/9 (166.4 per 100,000). Notably, females consistently displayed lower AM rates than males. Furthermore, both gender differences and the North–South gap of AM decreased during the period studied. The regions with the highest AM rates fluctuated throughout the study period. The highest percentage decrease in AM from 2006/7 to 2018/9, for both males (−41.3 %) and females (−34.2 %), was registered in the autonomous province of Trento, while the lowest reduction was observed in Molise for males (−17.4 %) and in Marche for females (−10.0 %). Conclusions: Remarkable gender and regional differences in AM between 2006 and 2019 have been recorded in Italy, although they have decreased over years. Continuous monitoring of AM and the implementation of region- and gender-specific interventions is essential to provide valuable insights for both policy and public health practice. This study contributes to the efforts to improve health equity between Italian regions

Characterization Of Commercial Magnetorheological Fluids At High Shear Rate: Influence Of The Gap

This paper reports the experimental tests on the behaviour of a commercial MR fluid at high shear rates and the effect of the gap. Three gaps were considered at multiple magnetic fields and shear rates. From an extended set of almost two hundred experimental flow curves, a set of parameters for the apparent viscosity are retrieved by using the Ostwald de Waele model for non-Newtonian fluids. It is possible to simplify the parameter correlation by making the following considerations: the consistency of the model depends only on the magnetic field, the flow index depends on the fluid type and the gap shows an important effect only at null or very low magnetic fields. This lead to a simple and useful model, especially in the design phase of a MR based product. During the off state, with no applied field, it is possible to use a standard viscous model. During the active state, with high magnetic field, a strong non-Newtonian nature becomes prevalent over the viscous one even at very high shear rate; the magnetic field dominates the apparent viscosity change, while the gap does not play any relevant role on the system behaviour. This simple assumption allows the designer to dimension the gap only considering the non-active state, as in standard viscous systems, and taking into account only the magnetic effect in the active state, where the gap does not change the proposed fluid model

automatic vending machines contamination a pilot study

Hot-drinks vending machines are disseminated worldwide and millions of drinks are served every day. Because of a small number of studies on hot-drinks related illnesses, the aim of this pilot study was to identify the presence and load of bacterial species, potentially harmful for consumers, within hot-drinks vending machines external critical surfaces. This preliminary cross sectional study was carried out in April 2015 at the University of Siena, Italy. Samples were taken from the critical surfaces of 4 hot-drinks vending machines (VM); the analyzed VM's critical surfaces were: Dispense Areas, Nozzles and Glass-Holders. The samples were sown on selective culture media: Plate Count Agar (PCA) at 22°C and 36°C, Slanetz and Bartely Agar (SBA) and Mannitol Salt Agar (MSA). Total Viable Count (TVC) at 36°C and 22°C was assessed for mesophilic and psychrophilic contamination. Results were expressed in terms of average CFU/cm2. Descriptive and statistical analyses were performed in order to assess which surface was the most contaminated. The nozzles resulted to be the most contaminated critical surface, showing average values over the limits in all the culture media (PCA 36°C, PCA 22°C, MSA and SBA). The statistical analysis showed that the nozzles were significantly more contaminated (p &lt;0.05) than Dispense Areas and Glass-holders both in PCA 36°C and in PCA 22°C. Given the high number of CFU/cm2, VM may constitute a potential threat for consumer's health, reason for which further studies are recommendable.</p

The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019

Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe

Time-Trends in Air Pollution Impact on Health in Italy, 1990–2019: An Analysis From the Global Burden of Disease Study 2019

Objectives: We explored temporal variations in disease burden of ambient particulate matter 2.5 μm or less in diameter (PM2.5) and ozone in Italy using estimates from the Global Burden of Disease Study 2019.Methods: We compared temporal changes and percent variations (95% Uncertainty Intervals [95% UI]) in rates of disability adjusted life years (DALYs), years of life lost, years lived with disability and mortality from 1990 to 2019, and variations in pollutant-attributable burden with those in the overall burden of each PM2.5- and ozone-related disease.Results: In 2019, 467,000 DALYs (95% UI: 371,000, 570,000) were attributable to PM2.5 and 39,600 (95% UI: 18,300, 61,500) to ozone. The crude DALY rate attributable to PM2.5 decreased by 47.9% (95% UI: 10.3, 65.4) from 1990 to 2019. For ozone, it declined by 37.0% (95% UI: 28.9, 44.5) during 1990–2010, but it increased by 44.8% (95% UI: 35.5, 56.3) during 2010–2019. Age-standardized rates declined more than crude ones.Conclusion: In Italy, the burden of ambient PM2.5 (but not of ozone) significantly decreased, even in concurrence with population ageing. Results suggest a positive impact of air quality regulations, fostering further regulatory efforts