Search

The decrease in the quality of raw materials coming for processing requires involvement of refractory ores in processing, the refractoriness of which is caused by the presence of organic carbonaceous matter sorption-active in relation to dissolved noble metals and impregnation of fine noble metals in mineral-carriers. In this connection, the actual research line is the development of new technological solutions with the use of energy methods of action in order to reduce the losses of valuable components in beneficiation tailings. Treatment with ultra-high frequency electromagnetic radiation has a number of advantages, including rapid and selective heating due to the differences in the ability of minerals to absorb this radiation. Carbon-containing materials represented by carbonaceous flotation concentrate and model samples of activated carbon with adsorbed silver were taken as the research subjects. Using the model samples as an example, the necessity of using magnetite to achieve coarsening fine silver particles during ultra-high frequency treatment was substantiated. The formation of active centers of local heating during the treatment in the points of magnetite addition was confirmed. The necessary content of magnetite of 10% for coarsening fine silver to spherical aggregates, the average size of which was 20–40 microns, was substantiated. Coarsening noble metal particles to sizes of 20–50 microns in treated carbonaceous concentrates containing silver and gold was achieved, when the substantiated amount of magnetite was added. Coarsened particles (aggregates) of noble metals can be recovered using traditional beneficiation methods.

The article deals with the use of natural color to reduce the level of introduction of sodium nitrite. Enzymatic rice is used as a dye. The value of meat products is determined not only by their ability to satisfy a person’s physiological need for nutrients and energy, but also by the attractiveness of organoleptic indicators. The modern consumer is accustomed to a certain color of meat products, associating with it their freshness and good quality. However, according to the totality of accumulated clinical observations, the use of nitrites, which fix the natural rose-red color of meat, is causing increasing medical concern. The article presents the functional and technological properties of model samples of boiled sausages with different content of dye and sodium nitrite. The obtained data on the study of the qualitative indicators of a new type of boiled sausages have shown that the product with the use of fermented rice in the recipe leads to the formation of a more intense color in the prototypes. The article shows the results of the study of the properties of raw minced meat and the quality indicators of the finished product. The results of the research have shown that the introduction of a dye into minced meat and a decrease in the proportion of the introduction of sodium nitrite leads to a decrease in residual sodium nitrite in boiled sausages. The use of a reduced amount of sodium nitrite together with fermented rice makes it possible to obtain a safer product with a low content of residual sodium nitrite – 0.34 mg%, in the control sample it is 3.5 mg%. Microbiological studies have shown that reducing the amount of sodium nitrite in the recipe and the presence of fermented rice does not affect the microbiological parameters of finished sausages. The expediency of using a natural dye in sausage production has been experimentally confirmed in order to reduce the level of sodium nitrite introduction.

• Binary mixtures of Cu-based greens pigments in variable percentage were prepared. • The effectiveness of ATR-FTIR and µRS to discriminate between binary mixtures was tested. • Spectral fingerprint was established for the pigments mixed and ageing. • Research was done on three masterpiece paintings from the Spanish Golden Age. • Mixture discrimination was achieved via ATR-FTIR even at low pigment proportions. Precise knowledge of the palette employed by historic painters is fundamental to preserving their works of art and can help pinpoint the period in which their paintings were created, their provenance and authorship. Raman and IR spectroscopy is successful in identifying pigments via their molecular spectrum, nevertheless, to distinguish the pigments in a binary mixture is challenging, particularly when the mixed pigments are the same colour and Cu-containing. This is precisely the aim of the current research: to evaluate the effectiveness of the molecular spectroscopy techniques µRS and µFTIR-ATR to discriminate binary mixtures of three green pigments, all containing copper, specifically copper resinate, malachite and verdigris. To that end, two sets of model samples were prepared with pure pigments and their binary mixtures in variable weight concentrations from 20% to 80% for each component. The 15 model samples obtained were mixed with linseed oil in the fixed proportion of 3:1 (w/w) of powdered pigment to binder and spread in a homogeneous layer on a support of commercial grade canvas. Five replicates of µFTIR-ATR and µRS spectra, respectively, were recorded after 0 h, 24 h, 48 h, 72 h and 144 h of exposure within the controlled conditions of a climatic chamber. The aim is to establish the minimum percentage of a Cu-containing pigment in a binary mixture that can be detected by µRS and/or µFTIR-ATR spectroscopy. The product of this ample study is a database of the spectroscopic signature of each pigment in the specific mixtures (in the given proportions and artificial ageing times) for reference purposes in the study of the green areas of selected masterpieces. The oil paintings used in the research (The Nativity, The Visitation , and The Assumption) are of Alonso Cano's work, a well-known artist of the Spanish Golden Age (the Siglo de Oro in Spanish). With this study, the knowledge of the mixture of green pigments employed in Cano's palette was expanded, making considerable progress in the ambitious National Projects in which our Research Group, ever since 2003, has been attempting to understand Cano's technique. [Display omitted] [ABSTRACT FROM AUTHOR]

The effect of thickening agents - methyl cellulose, hydroxyethyl cellulose, sodium carboxymethyl cellulose, and xanthan gum - solutions on the sensory viscosity was investigated in the concentration range of 0-0.8%. The perceived viscosity was proportional to the logarithm of kinematic viscosity in the presence of citric and malic acids. The viscosity was inversely proportional to the acidity at the viscosity levels higher than 10 mm2/s. A liquid of high viscosity thus possess lower acidity than aqueous or low-viscosity solutions. No significant differences were found between the effects of different thickening agents.

A functional immunohistochemical method for soya proteins detection was developed. The procedure is based on the avidin-biotin complex (ABC) method that attains sufficient sensitivity. The method was verified by the analysis of the model samples of different forms of soya additives containing various concentrations of soya isolate. The detection limit of soya present in the model samples was 0.5%. Different possibilities of the background staining were tested. The best results were obtained with the background staining according to Calleja. The results were confirmed by the accredited indirect ELISA method. The method allows the identification of various forms of soya proteins such as isolates, texturates, concentrates, and flour.

The effect of thickening agents - methyl cellulose, hydroxyethyl cellulose, sodium carboxymethyl cellulose, and xanthan gum - solutions on the sensory viscosity was investigated in the concentration range of 0-0.8%. The perceived viscosity was proportional to the logarithm of kinematic viscosity in the presence of citric and malic acids. The viscosity was inversely proportional to the acidity at the viscosity levels higher than 10 mm²/s. A liquid of high viscosity thus possess lower acidity than aqueous or low-viscosity solutions. No significant differences were found between the effects of different thickening agents. [ABSTRACT FROM AUTHOR]

Abstract: PdAg model films and real composite membranes were prepared by sequential electroless deposition on top of porous stainless steel supports. Their surface properties were investigated by X-ray photoelectron spectroscopy (XPS), Angle resolved XPS and sputtering depth profile. It was shown that the surface of the alloy was strongly enriched in silver after the annealing treatment up to 500 °C on hydrogen stream. A relationship between the Ag 3d5/2 core-level binding energy shift and the silver surface composition was observed from the XPS data obtained with the model samples. The surface composition of real membranes after both hydrogen permeation and reaction experiments showed silver enrichment, in agreement with the data obtained from the model sample. [Copyright &y& Elsevier]

Abstract: Gradient elution in CCC is a powerful tool, which needs further systematic development to become robust and easy to use. The first attempt to build a correlation between gradient elution profile and distribution ratio (K D) values for model mixtures containing typical representatives of pharmaceutical compounds is presented in this paper. The three step estimation of the solvent system composition of a heptane–ethyl acetate–methanol–water (HEMWat) series is described. The estimation is based on simple measurements of initial and final stationary phase retention for gradient elution run, calculating gradient distribution ratio and correlating it with static K D against HEMWat number. [Copyright &y& Elsevier]

• Waterlogged archaeological wood was modeled from fresh balsa wood. • One-week immersion in deionized water under vacuum is necessary to afterwards degrade the wood. • Iron sulfides were successfully formed through selected impregnation protocols. • Chemometrics approach allowed to validate spectroscopies analyses. Reduced iron and sulfur species accumulated within waterlogged archaeological wood artefacts during their burial time. Oxygen exposure of the artefacts during recovery leads to acidification and salts precipitation, which causes irreversible physical and chemical damages. Prior to accurately evaluating novel extraction methods, the procedures for creating analogous samples were evaluated for efficacy. Waterlogged wood analogues provide access to a whole set of homogeneous and sacrificial samples that replicate characteristics of waterlogged archaeological wood in terms of content degradation and the presence of reduced iron and sulfur species. In this study, we evaluated the preparation of model samples from fresh balsa wood artificially contaminated with reduced iron and sulfur species. Wood degradation and the formation of reduced iron and sulfur species were assessed by Fourier Transformed Infrared (FTIR) and Raman spectroscopies and validated through statistic methods, such as Principal Component Analysis (PCA). Among the three impregnation protocols investigated, one method appeared to be the most effective in term of iron sulfide formation, especially partially oxidized mackinawite Fe 1-x S. The selected protocol proved reproducible and efficient on both fresh balsa and Neolithic oak samples. From these observations confirmed by the PCA analyses on spectroscopic dataset, a suitable method to model waterlogged archaeological wood was established. [ABSTRACT FROM AUTHOR]