Assessment Techniques to Ensure Reliable Electrical Insulation for More Electric Transportation

Partial discharge testing of complete, low-voltage induction machines and dry-type convertor transformers for the More Electric Transportation is discussed. The current standard (i.e. IEC 60034-18-41, 60317-0-1 and 61378\u20131) offers very few answers to the new challenges posed to the insulating systems reliability of these increasingly electrified electrical machines. Based on tests performed on different kind of specimens and the literature, the most promising assessment technique to ensure a reliable insulation is based on optical sensors. In addition, this work seeks to give some precise, but simple, indications on how to take into account the effect of altitude and high frequency in the qualification of an insulation system for More Electric Transportation and the limits of the different standards involved are highlighted

(3R,5S)-5(3)-Carb­oxy-3,4,5,6-tetra­hydro-2H-1,4-thia­zin-4-ium-3(5)-carboxyl­ate

The molecule of the zwitterionic title compound, C6H9NO4S, which lies on a mirror plane, shows a puckered chair conformation of the six-membered ring with the S and N atoms out of the mean plane of the other four C atoms by 0.929 (2) and 0.647 (2) Å, respectively. The ionized carboxyl group is equatorially oriented. The hydrogen-bonding network includes very short O—H⋯O [2.470 (2) Å] and N—H⋯S [3.471 (2) and 3.416 (2) Å] inter­molecular contacts

Partial Discharge Phenomena in Electrical Machines for the More Electrical Aircraft. Part II: Impact of Reduced Pressures and Wide Bandgap Devices

This paper focuses on the inception of partial discharges within the insulation system of electrical actuators used for the More Electrical Aircraft (MEA). Since these machines should operate in the absence of Partial Discharges (PDs), the dependence of the PD Inception Voltage (PDIV) on voltage impulses typical of wide bandgap (SiC) devices is investigated at both 1 bar, reduced pressures close to those typical of aircraft cruising altitudes (150 mbar – 200 mbar) or lower (down to 5 mbar). Propagation issues are not dealt with here as results were obtained working on insulation models consisting of couples of wires twisted together (twisted pairs), thus knowing exactly the potential differences between all points of the insulation model. The results show that the rise times and the switching frequencies associated with wide bandgap devices have little impact on the PDIV. A model able to predict the PDIV of the turn/turn insulation of random wound motors (the most vulnerable part of the insulation) at different pressures is proposed. The model is also able to deal with temperature changes, with limitations that depend on the type on insulation systems

Diabetic Foot Infections:The Diagnostic Challenges

Diabetic foot infections (DFIs) are severe complications of long-standing diabetes, and they represent a diagnostic challenge, since the differentiation between osteomyelitis (OM), soft tissue infection (STI), and Charcot's osteoarthropathy is very difficult to achieve. Nevertheless, such differential diagnosis is mandatory in order to plan the most appropriate treatment for the patient. The isolation of the pathogen from bone or soft tissues is still the gold standard for diagnosis; however, it would be desirable to have a non-invasive test that is able to detect, localize, and evaluate the extent of the infection with high accuracy. A multidisciplinary approach is the key for the correct management of diabetic patients dealing with infective complications, but at the moment, no definite diagnostic flow charts still exist. This review aims at providing an overview on multimodality imaging for the diagnosis of DFI and to address evidence-based answers to the clinicians when they appeal to radiologists or nuclear medicine (NM) physicians for studying their patients

Transcriptome Adaptation of the Ovine Mammary Gland to Dietary Supplementation of Extruded Linseed

Several dietary strategies were adopted to reduce saturated fatty acids and increase beneficial fatty acids (FA) for human health. Few studies are available about the pathways/genes involved in these processes. Illumina RNA-sequencing was used to investigate changes in the ovine mammary gland transcriptome following supplemental feeding with 20% extruded linseed. Comisana ewes in mid-lactation were fed a control diet for 28 days (control period) followed by supplementation with 20% DM of linseed panel for 28 days (treatment period). Milk production was decreased by 30.46% with linseed supplementation. Moreover, a significant reduction in fat, protein and lactose secretion was also observed. Several unsaturated FAs were increased while short and medium chain saturated FAs were decreased by linseed treatment. Around four thousand (1795 up- and 2133 down-regulated) genes were significantly differentially regulated by linseed supplementation. The main pathways affected by linseed supplementation were those involved in the energy balance of the mammary gland. Principally, the mammary gland of fed linseed sheep showed a reduced abundance of transcripts related to the synthesis of lipids and carbohydrates and oxidative phosphorylation. Our study suggests that the observed decrease in milk saturated FA was correlated to down-regulation of genes in the lipid synthesis and lipid metabolism pathways

Work-related eye injuries: A relevant health problem. main epidemiological data from a highly-industrialized area of northern Italy

The province of Modena is one of the most industrialized areas of Northern Italy. The medical records of the Ophthalmological Emergency Department (OED) of Modena University Hospital were studied: there were 13, 470 OED accesses in 2014 and in 754 cases that an occupational eye injury occurred. The frequency of work-related eye injuries (3â°) was lower compared to other published studies, but the absolute number is still relevant, showing the need for more adequate prevention, especially in metal work, construction work, and agriculture, where the worst prognoses were observed. Intervention programs must be implemented as early as possible in the working life, considering that the frequency in younger workers is about double that of the oldest age class (3.5â°vs. 1.8â°), and special attention should also be given to foreigners, who have a 50% higher injury risk. Furthermore, the planning of specific interventions for eye-injured workers may be useful, considering that a previous injury does not appear to encourage the adoption of preventive interventions, and a subgroup of eye-injured workers have a potential risk for new injuries. Finally, the data presented here indicates how OED records, integrated with specific occupational information, can be applied for studies on work-related eye injuries

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

KEYNOTE PAPER UPDATE ON CONDENSATION HEAT TRANSFER AND PRESSURE DROP INSIDE MINICHANNELS

ABSTRACT The present paper reviews published experimental work focusing on condensation flow regimes, heat transfer and pressure drop in minichannels. New experimental data are available with high pressure (R410A), medium (R134a) and low pressure (R236ea) refrigerants in minichannels of different cross section geometry and with hydraulic diameters ranging from 0.4 to 3 mm. Because of the influence of flow regimes on heat transfer and pressure drop, a literature review is presented to discuss flow regimes transitions. The available experimental frictional pressure gradients and heat transfer coefficients are compared with semi empirical and theoretical models developed for conventional channels and with models specifically created for minichannels. Starting from the results of the comparison between experimental data and models, the paper will discuss and evaluate the opportunity for a new heat transfer model for condensation in minichannels; the new model attempts to take into account the effect of the entrainment rate of droplets from the liquid film

Effects of 00-rapeseed meal inclusion in Parmigiano Reggiano hay-based ration on dairy cows’ production, reticular pH and fibre digestibility

Hay-based diets are typically used in Parmigiano Reggiano cheese production. Parmigiano Reggiano feeding regulation prohibits 00-rapeseed dietary inclusion. The objectives of this study were to investigate the effects of substituting soybean-meal with different levels of 00-rapeseed-meal in dairy cows’ diets, to evaluate the possibility to include it in Parmigiano Reggiano regulation. The study had a Latin square design with 8 tie stall dairy cows. The isoenergetic and isoproteic dietary treatments differed in protein source (% of DM): S (0.0% 00-rapeseed-meal, 9.3% of soybean-meal), LR (3.8% 00-rapeseed-meal, 6.8% of soybean-meal), MR (8.5% 00-rapeseed-meal, 3.4% of soybean-meal), and HR (13.2% 00-rapeseed-meal, 0.0% of soybean-meal). DMI, milk production and composition, rumination and reticular-pH were recorded daily. Dietary fibre digestibility was evaluated by in vitro fermentation and milk gointrin content was quantified by liquid chromatography–tandem mass spectrometry. Statistical analysis was performed by mixed model. Milk yield, protein and casein content increased for incremental 00-rapeseed-meal dietary levels. MR treatment compared to the others resulted in higher daily reticular-pH (5.92), and fewer minutes with pH below 5.8 (467) and 5.5 (72). Goitrin was detectable in milk when 00-rapeseed-meal was included in the diet. Overall, the inclusion of 00-rapeseed-meal in the Parmigiano Reggiano type ratio did not compromise the performances of cows pointing to it as a reliable substitute for soybean-meal. Our results suggest that 00-rapeseed-meal should be tested in feeding studies to determine its effects on milk organoleptic characteristics and cheese production and quality to see if it can be included in the Italian PDO cheese regulation