1,009 research outputs found
In-Plane and Out-of-Plane MEMS Motion Sensors Based on Fringe Capacitances
Abstract New MEMS motion sensors have been developed. These prototypes are based on a sensing technique that exploits the fringe capacitance between two co-planar electrodes designed over a thin oxide layer covering a grounded wafer substrate. A relevant fraction of the electric-field streamlines, generated by the readout voltage applied between the electrodes, develops in the air (or vacuum) volume over the electrodes. A grounded suspended mass moving within this volume modifies the streamlines configuration, causing relative changes in the capacitance between the electrodes as large as the ∼80% of the initial value. Two types of devices based on the described concept have been designed and built in an industrial surface micromachining process, to sense acceleration in the direction both parallel and orthogonal to the substrate surface. The realized devices have been tested and a sensitivity of ∼0.9 fF/g and ∼0.2 fF/g has been obtained for the in plane and for the out-of-plane structures respectively
impact of coccidiosis control program and feeding plan on white striping prevalence and severity degree on broiler breast fillets evaluated at three growing ages
Abstract This study investigated the impact of 2 coccidiosis control systems (vaccine vs anticoccidial) and 2 feeding plans (standard energy vs low energy content, the latter supplemented with threonine and enzymes in the second half of the production cycle) on white striping (WS) prevalence and severity in chicken broiler breasts at commercial slaughter age (51 d). The age of lesion onset was also investigated with the sacrifice of 80 chicks at 12, and 80 chicks at 25 d of age. Seven hundred and twenty ROSS 708 strain male chicks were divided into 4 groups: a non-vaccinated group fed with standard diet (CONTROL); two groups vaccinated against coccidiosis but fed either a standard diet (VACC) or a low-energy diet supplemented with threonine and enzymes (VACC–LE plus); and a fourth group fed a standard diet containing anticoccidial additive except during the finishing period (COX). After live performance, yields, and fillet pH were measured, the breasts were weighed and scored as level 0 (no WS), level 1 (moderate WS), and level 2 (severe WS) at each of the 3 ages; data were covariate for slaughter weight. The results suggest an ameliorative effect of coccidiosis control systems when compared to the control group in terms of live weight, breast yield, and whole breast weight, with heavier fillets characterized by higher pH values. WS appeared at 25 d of age with an average prevalence of 11.5% and with lesions of moderate severity. There were no statistically significant differences due to the experimental treatment at this age. At commercial slaughter age, total average prevalence was 96%, with COX birds showing higher level 2 prevalence (77.6%). This could be related to the higher slaughter weight reached by the COX group (
Long-term hydrogeophysical monitoring of the internal conditions of river levees
To evaluate the vulnerability of the earthen levee of an irrigation canal in San Giacomo delle Segnate, Italy, a customized electrical resistivity tomography (ERT) monitoring system was installed in September 2015 and has been continuously operating since then. Thanks to a meteorological station deployed at the study site, we could investigate the relationship between the inverted resistivity values and different parameters, namely air temperature, rainfall and water level in the canal. Air temperature seems to have a minor but not negligible influence on resistivity variations, especially at shallow depth. A model of soil temperature versus depth was used to correct resistivity sections for air temperature variations through the different seasons. Changes of the water level in the canal and rainfall significantly affect measured resistivity values. At the study site, the most important variations of resistivity are related to saturation and dewatering processes in the irrigation periods. Although we explored the effect of drawdown procedures on resistivity data, this process, causing rapid variations of resistivity values, is still not completely understood because the canal is rapidly emptied during rainfall events. Therefore, the effect of variations of the water level in the canal on levee resistivity cannot be distinguished from the effect of rainfalls. To study the effect of water level variations alone, we considered the beginning of the irrigation period when the dry canal is gradually filled and we observed a smooth trend of resistivity changes. The effect of rainfall on the data was studied during different periods of the year and at different depths of the levee so that the resistivity variations could be evaluated under different conditions. To convert the inverted resistivity sections into water content maps, an empirical and site-dependent relationship between resistivity and water content was obtained using core samples. Water content data can then be used for the implementation of stability analysis using custom modeling. This study introduces an efficient technique to monitor earthen levees and to control the evolution of seepage and water saturation in pseudo-real time. Such a technique can be exploited by Public Administrations to reduce hydrogeological risks significantly
Tuning the Interlayer Distance of Graphene Oxide as a Function of the Oxidation Degree for o-Toluidine Removal
Graphene oxide (GO) with different oxidation degrees is prepared by a modified Hummers' method varying KMnO4 amount from 0.5 to 6.0 g. X-ray powder diffraction (XRPD), micro-Raman, thermogravimetric analysis, X-ray photoeelectron spectroscopy, Boehm titrations, high-resolution transmission electron microscopy, and, finally, positron annihilation lifetime spectroscopy (PALS) are exploited to assess the properties of GO. Results show that increasing oxidant species can tune the interlayer gap between GO sheets up to a maximum value in the case of 4.0 g KMnO4 content. Moreover, these results validate the two-component-based model of GO in which, at low oxidation degree, there are unsplit/isolated graphene planes, instead at higher oxidant amounts, a five-layer sandwiched configuration occurs comprising graphene planes having functional groups decorating the edges (bwGO), hydrated oxidative debris (OD) and "empty" spaces (revealed by PALS as the distance between (bwGO + OD) two-component layers). In addition, by XRPD analysis, the total gap between two sheets is easily computed. In order to correlate these findings to pollutant removal capability, planar o-toluidine adsorption is studied. Since this molecule diffuses in an aqueous environment, the obtained adsorption percentages are compared to the thickness of the hydrated OD grafted onto bwGO. A strict connection between the pollutant removal efficacy and the variation of the hydrated interlayer distance is found
Antimicrobial resistance among Escherichia coli that cause childhood community-acquired urinary tract infections in Northern Italy
<p>Abstracts</p> <p>Background</p> <p>Resistance rate of <it>Escherichia coli </it>against antimicrobials that are commonly prescribed in pediatric urinary tract infections is currently a matter of concern.</p> <p>Methods</p> <p>The antimicrobial susceptibility patterns of uropathogenic <it>Escherichia coli </it>strains to the common antibimcrobials ampicillin, cotrimoxazole, coamoxyclav, ceftazidime, ceftriaxone, nitrofurantoin, and gentamycin were determined in 177 children aged from 2 to 36 months. They presented with their first symptomatic community acquired urinary tract infection at the Department of Pediatrics, San Leopoldo Mandic Hospital, Merate-Lecco.</p> <p>Results</p> <p>High rates of ampicillin (inpatients: 50%; outpatients: 52%) resistance were identified. The resistance for cotrimoxazole (inpatients: 22%; outpatients: 15%) and especially coamoxyclav (inpatients: 6%; outpatients: 10%) was less pronounced than that to ampicillin. No resistance or less than 1% of resistance was identified for ceftazidime, ceftriaxone, nitrofurantoin, and gentamycin both in inpatients and in outpatients.</p> <p>Conclusions</p> <p>Italian children affected with a community acquired urinary tract infection are initially managed orally with coamoxyclav or parenterally with ceftriaxone. The results of the present retrospective analysis support this attitude. Parenteral ceftriaxone or an aminoglycoside should be considered for patients on antimicrobial prophylaxis or recently prescribed antimicrobials.</p
Noise spectra of SIU-GaAs pad detectors with guard rings
This paper presents current noise characterization of circular pad Schottky barrier diodes with guard rings. The diodes were fabricated from undopped semi-insulating GaAs, SIU-GaAs, at the University of Glasgow. Current noise spectra were obtained for the detectors for two pad sizes, with reverse bias applied. Three measurements were also made on one of the detectors under forward bias. The noise spectra show an excess noise component, with a low frequency corner at less than 1kHz, and a flat region at higher frequencies. The magnitude of the white noise is approximately half that expected from shot noise theory for the given leakage currents. A fall in the magnitude of the noise was observed at 20kHz which is attributed to the dielectric relaxation time of the material
Triphasic scaffolds for the regeneration of the bone-ligament interface
A triphasic scaffold (TPS) for the regeneration of the bone-ligament interface was fabricated combining a 3D fiber deposited polycaprolactone structure and a polylactic co-glycolic acid electrospun. The scaffold presented a gradient of physical and mechanical properties which elicited different biological responses from human mesenchymal stem cells. Biological test were performed on the whole TPS and on scaffolds comprised of each single part of the TPS, considered as the controls. The TPS showed an increase of the metabolic activity with culturing time that seemed to be an average of the controls at each time point. The importance of differentiation media for bone and ligament regeneration was further investigated. Metabolic activity analysis on the different areas of the TPS showed a similar trend after 7 days in both differentiation media. Total alkaline phosphatase (ALP) activity analysis showed a statistically higher activity of the TPS in mineralization medium compared to the controls. A different glycosaminoglycans amount between the TPS and its controls was detected, displaying a similar trend with respect to ALP activity. Results clearly indicated that the integration of electrospinning and additive manufacturing represents a promising approach for the fabrication of scaffolds for the regeneration of tissue interfaces, such as the bone-to-ligament one, because it allows mimicking the structural environment combining different biomaterials at different scales
Indoor Radon Surveying and Mitigation in the Case-Study of Celleno Town (Central Italy) Located in a Medium Geogenic Radon Potential Area
Indoor radon surveying and remediation were implemented in a single-family home affected by high levels of indoor radon in the Celleno municipality (central Italy) with the aim of identifying the contribution of radon sources, evaluating the factors affecting radon entry into the building, and reducing radon risk. Average radon levels were relatively low at the ground floor (286 ± 202 Bq m−3) and first floor (167 ± 84 Bq m−3) in autumn when the temperature was still warm and the windows were open, but increased up to 2776 ± 1768 Bq m−3 and 970 ± 202 Bq m−3 in the first half of December, when the heating system was on and the windows were closed. The inner walls of the pilot room at the ground floor, semi buried on one side, were then treated with a waterproof product (a silane terminated polymer) and the average radon was halved (1475 ± 1092 Bq m−3) in the following month, which was still characterised by winter conditions. Radon entry in the room was identified and sealed with the same product, and a radon accumulation space behind a NE-SW oriented wall was naturally ventilated, reducing radon below the reference level in April with northerly winds conditions
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