Testing the effects of temperature and humidity on printed passive UHF RFID tags on paper substrate

This article is an interesting substrate material for environmental-friendly printable electronics. In this study, screen-printed RFID tags on paper substrate are examined. Their reliability was tested with low temperature, high temperature, slow temperature cycling, high temperature and high humidity and water dipping test. Environmental stresses affect the tag antenna impedance, losses and radiation characteristics due to their impact on the ink film and paper substrate. Low temperature, temperature cycling and high humidity did not have a radical effect on the measured parameters: threshold power, backscattered signal power or read range of the tags. However, the frequency response and the losses of the tags were slightly affected. Exposure to high temperature was found to even improve the tag performance due to the positive effect of high temperature on the ink film. The combined high humidity and high temperature had the most severe effect on the tag performance. The threshold power increased, backscattered power decreased and the read range was shortened. On the whole, the results showed that field use of these tags in high, low and changing temperature conditions and high humidity conditions is possible. Use of these tags in combined high-humidity and high-temperature conditions should be carefully considered.     

Zein-based anti-browning cling wraps for fresh-cut apple slices

The usage of cling wraps is emerging as an easy and cost-effective approach to protect fresh-cut fruits and vegetables from dust, whilst improving visual appeal on retail counters. This study focused on developing an alternate, protein-based packaging material as a food grade cling wrap for food packaging applications. Zein-based cling wraps were produced, and their physical and mechanical characteristics were evaluated and compared with conventionally used chitosan biopolymer films and commercial synthetic polymer films. Antioxidant potential of the prepared films was studied, and the effectiveness of the developed films as anti-browning cling wraps was evaluated using studies conducted on fresh-cut apple slices at ambient conditions. Anti-browning effects were in par with polymeric counterparts; however, zein cling wraps could better prevent weight loss in apple slices. Zein-based films can be adopted as biodegradable food grade cling wraps as an alternative to chitosan and synthetic polymeric materials.     

Tracing enteric viruses in the European berry fruit supply chain

In recent years, numerous foodborne outbreaks due to consumption of berry fruit contaminated by human enteric viruses have been reported. This European multinational study investigated possible contamination routes by monitoring the entire food chain for a panel of human and animal enteric viruses.     

Comprehensive studies on polyethylenimine filled polypropylene and its potential application in carbon dioxide sequestration

Polypropylene (PP) was blended with branched polyethylenimine (PEI) with the aim to prepare blends having CO₂ adsorption property. The CO₂ adsorption properties will be conferred due to the presence of variety of amine functionality in PEI. PEI contains primary, secondary as well as tertiary amine groups. Before testing CO₂ adsorption, PP–PEI blends were characterized using variety of techniques, for example, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, scanning electron microscopy, and polarized light optical microscopy. In this work, we have studied in detail both compatibilized as well as noncompatibilized blends of PP and PEI. The compatibilization was achieved via addition of maleic anhydride grafted PP. Finally, all the compatibilized as well as noncompatibilized blends were studied for CO₂ adsorption. The compatibilized blends showed better thermal, mechanical as well as CO₂ adsorption properties as compared to the noncompatibilized blends. POLYM. ENG. SCI., 59:2092–2102, 2019. © 2019 Society of Plastics Engineers     

Synthesis and characterization of electrically conducting copolymer of aniline and o‐bromoaniline using methane sulfonic acid as dopant

Polyaniline (PAN), poly(o‐bromoaniline) (POBA), and poly(aniline‐co‐o‐bromoaniline) (PABA) were synthesized by oxidative coupling. These polymers are protonated by 10–20% methane sulfonic acid (MSA) and 1M HCl. The new polymer bases have greater solubility than that of PAN in common polar organic solvents; PAN–MSA was observed to be the most thermally stable of these polymers. POBA is associated with residual quinoid diimine units as illustrated in the IR and UV‐vis spectra, after reduction with hydrazine dihydrochloride. Both the doping agents cause a downward shift of the quinoid absorption in the IR spectra. MSA‐ and HCl‐doped PAN and PABA polymers exhibit a coil‐like conformation in DMSO, whereas only MSA‐doped PAN and PABA show an “expanded coil‐like” conformation in m‐cresol with a “free carrier tail” above 800 nm in their electronic spectra. XPS spectra indicated the presence of covalent bromine in the POBA and PABA polymers. Bromine retention was greater in the homopolymer as evidenced by the IR studies after aging at 350°C. Compared to HCl, MSA is found to be a more effective dopant, enhancing the conductivity of the copolymers by 10²–10³ times in magnitude. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2662–2669, 2002     

T–T–T behaviour of bioactive glasses 1–98 and 13–93

In this work crystallization kinetics of bioactive glasses 1–98 and 13–93 are discussed. Within a certain temperature–time window these glasses can be hot worked into various products without interfering with crystallization. The crystallization was studied isothermally by heating glass plates at different temperatures for different times. Phases in the samples were studied through XRD and SEM analyses. The nucleation-like curves and crystallization characteristics were measured with DTA. The temperature of maximum nucleation was measured for glass 1–98 at 725 °C and for 13–93 at 700 °C. The activation energy of crystallization of both glasses was 280 kJ/mol. The Johnson–Mehl–Avrami exponent and the SEM micrographs of the samples suggested surface crystallization. The primary crystalline phase was wollastonite. The growth rate of the crystallized surface layer was 1 order of magnitude higher in the plates of 1–98 than in 13–93. The results can be utilized to optimize the parameters in hot-working of the glasses.     

Room temperature efficacious synthesis of diphenylmethane over Fe/Al-MCM-41 catalysts

Fe/Al-MCM-41 (Si/Al = 25, 50, 75 and 100) were synthesized. Their catalytic activity was evaluated towards benzylation of benzene with benzyl chloride in liquid phase. The catalytic activity of Fe/Al-MCM-41(25) was higher than the other catalysts. Diphenylmethane(DPM) was obtained as the major product with 100% selectivity and with 100% conversion of benzyl chloride under optimum condition. The effect of temperature and the feed ratio, on the activity of Fe/Al-MCM-41(25) and selectivity towards DPM was studied and a possible reaction mechanism was proposed.     

The effect of seasonal variation on automated land cover mapping from multispectral airborne laser scanning data

Multispectral airborne laser scanning (MS-ALS) sensors are a new promising source of data for automated mapping methods. Finding an optimal time for data acquisition is important in all mapping applications based on remotely sensed datasets. In this study, three MS-ALS datasets acquired at different times of the growing season were compared for automated land cover mapping and road detection in a suburban area. In addition, changes in the intensity were studied. An object-based random forest classification was carried out using reference points. The overall accuracy of the land cover classification was 93.9% (May dataset), 96.4% (June) and 95.9% (August). The use of the May dataset acquired under leafless conditions resulted in more complete roads than the other datasets acquired when trees were in leaf. It was concluded that all datasets used in the study are applicable for suburban land cover mapping, however small differences in accuracies between land cover classes exist.