Establishment of metrological parameters of the method for measuring the protein mass fraction in fish food products by the Kjeldahl method

In laboratory practice, there are many protein quantification methods, and all of them have their own advantages and disadvantages. The most common and widely used method for the protein analysis in food products, including fish, is the Kjeldahl method. However, the current standards for measurement methods for the determination of the protein content in fish food products do not provide for the use of devices that meet the modern level of technical development, and also do not contain metrological indicators that guarantee the reliability of the results obtained. The aim of the study was to substantiate the method for measuring the protein mass fraction in fish food products by the Kjeldahl method on an automatic analyzer and to establish metrological parameters. The assessment of the quality indicators of the Kjeldahl measuring method was carried out using a Kjeltec System 2300 Nitrogen Analyzer (Foss Analytical AB, Sweden) in the form of a characteristic of the measurement error and its components, which will provide results with the required accuracy.

Textronics spacer knitted material tests as a key element of the diagnostic system that monitors above the proper level of seat vibration

This research is focused on the construction and examination of a prototype of a spacer knitted material with integrated sensors. The combination of textiles with elements of electronics, computer science, and a knowledge of automation is called textronics. This type of material has been proposed as a component of diagnostic systems to monitor the extension level of vibration in employee seats at selected workstations or in children’s chairs. The purpose of the diagnostic system is to improve personal protective equipment (PPE) and increase employee safety. The spacer knitted material was tested with vibration frequencies in the range of 0–40 Hz to develop metrological properties under reproducible and repeatable conditions. The tested spacer knitted material meets the requirements of sensory properties such as vibration. The tested material is characterized by the following metrological parameters: total uncertainty U = 4.5%, sensitivity Sa = 0.64 [V/s2/m] and excitability threshold of 5 Pa with simultaneous high coefficient of low-frequency vibration damping of effective amplitude transmissibility (SEAT) = 2.3. Spacer knitted materials are modern constructs that enable the creation of new hybrid structures that have other properties, e.g., sensory suppression, in addition to spatial form.

Unsteady force measurements on propeller model in cavitation tunnels

Object and purpose of research. This paper discusses longitudinal unsteady force dynamometer for cavitation tunnel tests. The purpose of the study is to improve metrological performance of the dynamometer and extend the scope of its application. Materials and methods. The study is based on metrological parameters of dynamometers and model test data available with KSRC Large Cavitation Tunnel (LCT). Main results. Development, manufacturing, certification and commissioning of longitudinal unsteady force dynamometer based on piezoceramic load cell with improved metrological performance making it applicable for model testing of not only propellers but also other types of marine propulsors. Conclusion. Dynamometer with piezoceramic load cell offers more accurate measurement of unsteady forces, wider band of measurement frequencies, as well as wider spectrum of possible applications and lower susceptibility to interference.

APPLICATION OF MICROCOLUMN HPLC-UV FOR RAPID QUANTITATIVE ANALYSIS OF ARBUTIN, BERGEN-IN AND GALLIC ACID IN BERGENIA CRASSIFOLIA

This work is aimed at the development of a microcolumn HPLC-UV assay for the rapid quantitative analysis of arbutin, bergenin, and gallic acid in Bergenia crassifolia. The results obtained indicate appropriate metrological parameters of the developed assay. It was found that the known methods of quantitative analysis of phenolic glycosides using SPE-spectrophotometry cannot be characterized as selective and accurate, due to the fact that the presences of the impurity compounds that do not belong to the group of phenolic glycosides negatively influenced the results. The developed assay was used for quantitative analysis of wild and commercial samples of B. crassifolia raw material. It was found that the content of arbutin, bergenin, and gallic acid in samples of B. crassifolia rhizomes collected in the Republic of Buryatia was 38.58–45.97, 66.74–139.76 and 1.22–1.65 mg/g, respectively, and for commercial batches of raw materials 20.57–41.37, 35.04–83.94 and 0.22–1.28 mg/g, respectively. It was found that the process of gradual enzymatic changes in the color of B. crassifolia leaves (green, red, black) leads to significant changes in the chemical composition. The most pronounced phenomenon is the degradation of bergenin, the presence of which is noted only in green leaves. The concentration of gallic acid is reduced in black leaves. Arbutin is characterized by an increased content in red leaves (102.02 mg/g). Additionally, a quantitative analysis of the peduncles and flowers of B. crassifolia was realized, and it was shown that they are distinguished by a high content of arbutin 48.40 and 42.15 mg/g, respectively, as well as bergenin in flowers (16.89 mg/g). The study demonstrated that the developed technique can be applied for a quick, selective, and accurate quantitative analysis of three compounds in various organs of B. crassifolia.

Comparison of SEM-Assisted Nanoporometric and Microporometric Morphometric Techniques Applied for the Ultramicroporous Polymer Films

One of the most important applications of polymeric porous nanomaterials is the design of nanoporous structures for operation in patch-clamp systems allowing to establish a gigaohm contact, as well as for the measurements of biomolecules, informational macromolecules, including DNA, translocating through the nanopore arrays. Development of nanopore sequencing techniques leads to fundamentally new big data arrays, but their representativeness and validity, as well as the validity of counting of biomacromolecular particles based on ultramicropore arrays, strongly depends both on the pore size (in engineering lithography unimodal pore size distribution is optimal) and the accuracy of the size distribution measurements using instrumental methods. However, the former is unattainable when using soft matter or stretchable, plastic and elastic polymer materials and films, while the latter depends on the metrological parameters of the instrumental and algorithmic porosimetry techniques. Therefore in this paper the question about the applicability of polymer materials with pore arrays for the studies of biomacromolecules and bionanostructures is proposed to be answered using a comparative analysis of two different porosimetry approaches with the resolution not lower than electron microscopic one.

Two-Stage Clock-Free Time-to-Digital Converter Based on Vernier and Tapped Delay Lines in FPGA Device

This article presents an idea, design and test results of a new time-to-digital converter (TDC) implemented in an FPGA device. The high resolution of 13 ps and measurement range of 3.4 ns are achieved based on a two-stage time interpolation (TI). In the first and second stages of the TI we have used the Vernier delay line and a single tapped delay line, respectively. This solution provides respectable metrological parameters without the need to use a clock signal, and significantly saves the logical resources of an integrated circuit (IC). The proposed method, generally based on two different variants of the discrete delay line, is easy to design and implement in digital ICs. For experimental verification, the TDC was implemented in a single programmable device from family Virtex-7 (Xilinx).

The Relationship between Metrological Parameters and Total Airborne Pollen Concentration in Atmosphere of Khartoum City During 2018

This study is aimed to find out the effect and relationship between metrological parameters and total airborne pollen concentration in atmosphere in Khartoum city (Sudan). For that purpose, one-year data during 2018 of Total Airborne Pollen Concentration (TAPC) and meteorological parameters is utilized. Pollen concentration in the atmosphere was measured using Non-volumetric air sampler (Vertical cylinder spore trap). The descriptive statistic of TAPC and metrological parameters were presented. The result showed TAPC in 2018 reached to their maximum in August (37.5/m³), and the minimum in June (14/ m³). Analysis of the relationship between TAPC and meteorological parameters showed that variations in the pollen concentrations were mainly affected by maximum temperature. In addition, there were substantial differences in these relationships in different seasons. In Autumn, they were affected by the rain falls, maximum temperature and relative humidity; in summer, they were affected by maximum temperature; and in winter, they were affected by maximum temperature and relative humidity. Temperature, rain falls and relative humidity promote plant growth and blooming. As well as the results show wind direction was significant on seasonally TAPC especially in Autumn. The results found significant effects between the meteorological on TAPC, were it is showed 72 % are affecting on TAPC refer to meteorological parameters and 28 % refer to another factors.