Low‐cost dye‐sensitized solar cells with ball‐milled tellurium‐doped graphene as counter electrodes and a natural sensitizer dye

This paper presents a facile and economic development of dye‐sensitized solar cells using a nonprecious counter electrode made from ball‐milled tellurium‐doped graphene (Te‐Gr) and a natural sensitizer extracted from Calotropis gigantea leaves. The prepared materials were characterized using various techniques, such as Raman spectroscopy, X‐ray diffraction (XRD), atomic force microscopy (AFM), impedance spectroscopy, and scanning electron microscopy with built‐in energy‐dispersive X‐ray spectroscopy (SEM with EDS). The electrochemical activity of the produced counter electrodes and the impedance of the fabricated cells were examined and discussed to devise plans for future enhancement of cell performance. A clear pattern of improvement was found when using cost‐effective Te‐Gr relative to the costly platinum counter electrodes, especially when compared with cells employing another natural sensitizer. The results show approximately 51% enhancement over chlorophyll‐based cells made from spinach, where the added advantage in our approach is the utilization of an abundant plant extract with little nutritional appeal.     

Correction to: Security analysis of an audio data encryption scheme based on key chaining and DNA encoding

Multimedia Tools and Applications - A Correction to this paper has been published: https://doi.org/10.1007/s11042-021-10592-x     

The propagation of pressure in a gelled waxy oil pipeline as studied by particle imaging velocimetry

Paraffinic crude oils in pipelines may form waxy gels during flow shutdowns. These gels can be dislodged by applying pressure if the wall shear stress, proportional to the local pressure gradient, exceeds the gel yield stress. The simplest models assume that the axial pressure profile becomes linear immediately after a jump in upstream pressure, but this fails to account for gel time‐dependent rheology or the effect of gel voids on pressure wave propagation. To investigate the former factor, pressure profile and particle imaging velocimetry (PIV) measurements were performed on a model oil gelled under pressure to reduce void formation. After a jump in upstream pressure to a value insufficient to restart flow, the axial pressure profile becomes linear in a two‐step process, with an immediate small rise in downstream pressure followed by a time‐delayed jump. The local downstream gel deformation measured by PIV exhibits similar two‐step time dependence. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Formation of carbide phases upon the mechanosynthesis of the (Fe<Subscript>0.93</Subscript>Cr<Subscript>0.07</Subscript>)<Subscript>75</Subscript>C<Subscript>25</Subscript> alloy compared with other carbide-forming processes

Methods of X-ray diffraction, differential thermal analysis, and measurements of the dynamic magnetic susceptibility have been used to investigate the sequence of phase transformations upon the mechanical alloying of a mixture of powders of the initial components of the composition (Fe_0.93Cr_.07)₇₅C₂₅. It has been shown that, at later stages of mechanical alloying, the phase composition is determined by the conditions of the dynamic equilibrium between the crystalline and amorphous phases. A change in the conditions of mechanical alloying leads to a shift in this equilibrium and to a change in the phase composition of the alloy. A comparison of carbide formation in the Fe–C system upon the mechanosynthesis, tempering of martensite, the saturation of iron with carbon from the gaseous medium, the quenching of the melt, and the sputtering deposition of films has been performed. Some general regularities have been established, from which it follows that an important role in phase formation upon the mechanosynthesis, just as in other abovementioned processes, is played by the thermally activated phenomena.     

Changes in glycoalkaloid and nitrate content in potatoes during dehydrated dice processing

The aim of this experiment was the determination of glycoalkaloid and nitrate content in potatoes during stages of processing into dry potato dice.Samples obtained from the tubers of three potato varieties were used: a very early Denar variety of Polish origin; Innovator, an early Dutch variety; and a Polish medium early Pasat variety. There were sampled three times from the factory store in 2009 and 2010. The potatoes were diced in laboratory conditions, by first peeling with a carborundum peeler, dicing into 10 × 10 × 10 mm pieces and rinsing with water at a temperature of 20 °C. In the next stages, the diced potatoes were blanched in water at a temperature of 75 °C for 5 min then dried in a laboratory drier for 1 h at 120 °C. After 1 h of drying, the temperature was lowered to 55-60 °C in order to obtain a defined final moisture content of 8-11%.In the raw material, intermediates and finished products, the concentrations of glycoalkaloids (α-chaconine and α-solanine) were determined using an HPLC method, and nitrates were determined colorimetrically using an RQflex analyser.It was found that the processes used in dried potato dice production significantly decreased concentrations of glycoalkaloids (α-chaconine and α-solanine) in intermediate and finished products when compared to raw material. The highest decrease in the quantity of glycoalkaloids occurred during peeling (33%) and after blanching (17%) of peeled potato. Nitrate content fell the most after cutting and rinsing with water (13%), and after blanching (23%). On average, dry potato dice contained 44% of the initial quantity of glycoalkaloids and 40% nitrate content in the final dried product.     

The effect of probiotics (Lactobacillus rhamnosus HN001, Lactobacillus paracasei LPC-37, and Lactobacillus acidophilus NCFM) on the availability of minerals from Dutch-type cheese

The use of probiotic cultures in the production of Dutch-type cheeses did not lead to significant changes in their chemical composition but it lowered their acidity. The availability of calcium and magnesium analyzed by in vitro enzymatic hydrolysis was 19 and 35%, respectively; the availability of phosphorus was significantly higher, at >90%. The use of probiotic cultures significantly increased the availability of calcium (~2.5%), phosphorus (~6%), and magnesium (~18%). The in vitro method supports accurate determination of the effect of the Lactobacillus spp. cultures on the availability of mineral compounds ingested with Dutch-type cheese.