Characteristics of a Graphene Nanoplatelet Anode in Advanced Lithium‐Ion Batteries Using Ionic Liquid Added by a Carbonate Electrolyte

A Cu‐supported, graphene nanoplatelet (GNP) electrodes are reported a as high performance anode in lithium ion battery. The electrode precursor is an easy‐to‐handle aqueous ink cast on cupper foil and following dried in air. The scanning electron microscopy evidences homogeneous, micrometric flakes‐like morphology. Electrochemical tests in conventional electrolyte reveal a capacity of about 450 mAh g⁻¹ over 300 cycles, delivered at a current rate as high as 740 mA g⁻¹. The graphene‐based electrode is characterized using a N‐butyl‐N‐methyl‐pyrrolidiniumbis (trifluoromethanesulfonyl) imide, lithium‐bis(trifluoromethanesulfonyl)imide (Py_1,4TFSI–LiTFSI) ionic liquid‐based solution added by ethylene carbonate (EC): dimethyl carbonate (DMC). The Li‐electrolyte interface is investigated by galvanostatic and potentiostatic techniques as well as by electrochemical impedance spectroscopy, in order to allow the use of the graphene‐nanoplatelets as anode in advanced lithium‐ion battery. Indeed, the electrode is coupled with a LiFePO₄ cathode in a battery having a relevant safety content, due to the ionic liquid‐based electrolyte that is characterized by an ionic conductivity of the order of 10⁻² S cm⁻¹, a transference number of 0.38 and a high electrochemical stability. The lithium ion battery delivers a capacity of the order of 150 mAh g⁻¹ with an efficiency approaching 100%, thus suggesting the suitability of GNPs anode for application in advanced configuration energy storage systems.     

Suspended InAs Nanowire-Based Devices for Thermal Conductivity Measurement Using the 3<Emphasis Type="Italic">ω</Emphasis> Method

We demonstrated device architectures implementing suspended InAs nanowires for thermal conductivity measurements. To this aim, we exploited a fabrication protocol involving the use of a sacrificial layer. The relatively large aspect ratio of our nanostructures combined with their low electrical resistance allows to exploit the four-probe 3ω technique to measure the thermal conductivity, inducing electrical self-heating in the nanowire at frequency ω and measuring the voltage drop across the nanostructure at frequency 3ω. In our systems, field effect modulation of the transport properties can be achieved exploiting fabricated side-gate electrodes in combination with the SiO₂/Si?++?substrate acting as a back gate. Our device architectures can open new routes to the all-electrical investigation of thermal parameters in III-V semiconductor nanowires, with a potential impact on thermoelectric applications.     

Improvement of Mass Transfer by Freezing Pre-treatment and Ultrasound Application on the Convective Drying of Beetroot (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.)

The effects of freezing pre-treatment and ultrasound application during drying on microstructure, drying curves, and bioactive compounds of beetroot have been evaluated. Raw and previously frozen (at ? 20 °C) beetroots were convectively dried (40 °C and 1 m/s) with and without ultrasound application using two acoustic densities (16.4 and 26.7 kW/m³), and a diffusional model was proposed to simulate the drying curves. Freezing pre-treatment and ultrasound application caused significant disruptions in the beetroot microstructure and reduced the drying time, enhancing the mass transfer. The external mass transfer coefficient significantly (p < 0.05) increased by 28–49% when ultrasound was applied; moreover, the effective diffusion coefficient significantly (p < 0.05) increased by 60–73% and 204–211%, respectively, due to the ultrasound application on the drying of raw and pre-frozen samples. Freezing caused significant (p < 0.05) increases in betalain and total polyphenol contents and antioxidant activity compared with the raw sample (16–57%), probably due to the release of free forms from the food matrix; meanwhile, drying had the opposite effect (8–54% decrease). Significantly (p < 0.05) higher decreases (32–81%) in bioactive compounds and antioxidant activity were observed when drying was assisted by ultrasound compared with dying without ultrasound. Therefore, freezing pre-treatment and ultrasound application enhanced mass transfer during drying. However, significant changes in quality parameters of the final product were observed.     

Raw milk from vending machines: Effects of boiling,microwave treatment,and refrigeration on microbiological quality

In Italy, the sale of raw milk from vending machines has been allowed since 2004. Boiling treatment before its use is mandatory for the consumer, because the raw milk could be an important source of foodborne pathogens. This study fits into this context with the aim to evaluate the microbiological quality of 30 raw milk samples periodically collected (March 2013 to July 2013) from 3 vending machines located in Molise, a region of southern Italy. Milk samples were stored for 72 h at 4°C and then subjected to different treatments, such as boiling and microwaving, to simulate domestic handling. The results show that all the raw milk samples examined immediately after their collection were affected by high microbial loads, with values very close to or even greater than those acceptable by Italian law. The microbial populations increased during refrigeration, reaching after 72 h values of about 8.0 log cfu/mL for Pseudomonas spp., 6.5 log cfu/mL for yeasts, and up to 4.0 log cfu/mL for Enterobacteriaceae. Boiling treatment, applied after 72 h to refrigerated milk samples, caused complete decontamination, but negatively affected the nutritional quality of the milk, as demonstrated by a drastic reduction of whey proteins. The microwave treatment at 900 W for 75 s produced microbiological decontamination similar to that of boiling, preserving the content in whey proteins of milk. The microbiological characteristics of raw milk observed in this study fully justify the obligation to boil the raw milk from vending machines before consumption. However, this study also showed that domestic boiling causes a drastic reduction in the nutritional value of milk. Microwave treatment could represent a good alternative to boiling, on the condition that the process variables are standardized for safe domestic application.     

Influence of barley variety, timing of nitrogen fertilisation and sunn pest infestation on malting and brewing

BACKGROUND: This paper presents a multivariate approach to investigate the influence of barley variety, timing of nitrogen fertilisation and sunn pest infestation on malting and brewing. Four spring and two winter barley varieties were grown in one location in southern Europe. Moreover, one of the spring varieties was infested with sunn pest, in order to study the effects of this pest on malting quality, and subjected to different nitrogen fertilisation timing regimes. The samples were micromalted, mashed, brewed and analysed. RESULTS: The data showed that even though the two winter barleys seemed to be the best regarding their physical appearance (sieving fraction I + II > 82%), this superiority was not confirmed in the malt samples, which showed low values of Hartong extract (27.1%) and high values of pH (6.07–6.11) and β‐glucan content (12.5–13.2 g kg^?1), resulting in low‐quality beers. The barley sample subjected to postponed fertilisation had a total nitrogen content (19.5 g kg^?1 dry matter) exceeding the specification for malting barley and gave a beer with a low content of free amino nitrogen (47 mg L^?1) and high values of viscosity (1.99 cP) and β‐glucan content (533 mg L^?1). The beer obtained from the barley sample subjected to pest attack had good quality parameters. CONCLUSION: All spring barleys gave well‐modified malts and consequently beers of higher quality than the winter barleys. Moreover, postponed fertilisation was negatively related to the quality of the final beer, and sunn pest infestation did not induce important economic losses in the beer production chain. Copyright © 2010 Society of Chemical Industry     

Pulsed field, PCR ribotyping and multiplex PCR analysis of Yersinia enterocolitica strains isolated from meat food in San Luis Argentina

The characterization of phenotypic and genotypic virulence markers of Yersinia enterocolitica strains belonging to biotypes (B) 1A, 2 and 3, mostly isolated from food in San Luis, Argentina, and the assessment of their genotypic diversity using PFGE and PCR ribotyping, were performed in our laboratory for the first time. Thirty five Y. enterocolitica strains, two reference strains and 33 strains isolated in our laboratory were studied. The presence of virF, ail, ystA, and myfA genes was investigated by multiplex PCR. The pathogenic potential of B1A strains, the most predominant biotype of Y. enterocolitica strains isolated from meat in our region, was investigated by simple PCR. Four B1A strains were positive for ystB gene. Four Y. enterocolitica 2/O:9 (bio/serotype) and two 3/O:5 strains isolated in our laboratory showed virulence-related results in the phenotypic tests and multiplex PCR. A good correlation between the expression of virulence markers and their corresponding genotypes was observed for most strains. Sixteen genomic types (GT) and 9 different intergenic spacer region (SR) groups were generated by PFGE and PCR ribotyping, respectively. In both cases the Y. enterocolitica 2/O:9 strains were separately clustered from 1A and 3/O:5 strains. Meat foods might be vehicles of transmission of pathogenic Y. enterocolitica strains in our region.