Розробка методу визначення динамічних параметрів оператора мобільної пожежної установки на базі сігвею

A method for determining the dynamic parameters of the operator of a mobile fire engine based on a segway, which fully characterize its dynamic properties – delay time and inertia was developed. The development of the method includes four stages. At the first stage, the problem of obtaining analytical relationships for determining the dynamic parameters of the operator is solved. These relationships include the frequency characteristics of the operator at a fixed frequency and its static parameter. At the second stage, the choice of a fixed frequency is substantiated using a criterion that minimizes errors in determining the dynamic parameters. It is shown that the fixed frequency for the characteristic parameters of the operator does not exceed 0.5 Hz. The third stage includes substantiation of the procedure for determining the frequency characteristics of the operator and its static parameter. The frequency characteristics of the operator at a fixed frequency and its static parameter are determined numerically. This procedure is based on using the data obtained by measuring the values of the operator’s transfer function at fixed time intervals. To obtain data, an interactive analog engine is used, which can also perform the functions of a simulator. The time intervals are chosen according to the Kotelnikov-Nyquist-Shannon theorem. At the last stage, the procedure for determining the dynamic parameters of the operator of a segway-based mobile fire engine is described. It is shown that the error in determining the dynamic parameters of the operator of a mobile fire engine does not exceed 9.0 %, if the error in determining its frequency characteristics at a frequency of 2.5 s–1 does not exceed 2.0 %Применительно к оператору мобильной пожарной установки на базе cигвея разработан метод определения его динамических параметров, которые полностью характеризуют его динамические свойства – время запаздывания и инерционность. Разработка метода включает четыре этапа. На первом этапе решается задача по получению аналитических зависимостей для определения динамических параметров оператора. Эти зависимости включают значение частотных характеристик оператора на фиксированной частоте и его статический параметр. На втором этапе обосновывается выбор фиксированной частоты, осуществляемый с использованием критерия, который минимизирует величины погрешностей определения динамических параметров. Показано, что величина фиксированной частоты для характерных параметров оператора не превышает 0,5 Гц. Третий этап включает обоснование процедуры получения значений частотных характеристик оператора и его статического параметра. Частотные характеристики оператора на фиксированной частоте и величина его статического параметра получены численным путем. Эта процедура основана на использовании массива данных, который получен путем измерения значений переходной функции оператора через фиксированные интервалы времени. Для получения массива данных используется интерактивная установка-аналог, которая может выполнять и функции тренажера. Интервалы времени выбираются согласно теореме Котельникова - Найквиста - Шеннона. На последнем этапе дается описание процедуры определения динамических параметров оператора мобильной пожарной установки на базе сигвея. Показано, что погрешность определения динамических параметров оператора мобильной пожарной установки не превышает 9,0 %, если погрешность определения его частотных характеристик на частоте 2,5 с-1 не превышает 2,0 %Стосовно до оператора мобільної пожежної установки на базі сігвею розроблено метод визначення його динамічних параметрів, які повністю характеризують його динамічні властивості – час запізнення та інерційність. Розробка методу включає чотири етапи. На першому етапі вирішується задача по одержанню аналітичних залежностей для визначення динамічних параметрів оператора. Ці залежності включають значення частотних характеристик оператора на фіксованій частоті та його статичний параметр. На другому етапі обґрунтовується вибір фіксованої частоти, що здійснюється із використанням критерію, який мінімізує величини похибок визначення динамічних параметрів. Показано, що величина фіксованої частоти для характерних параметрів оператора не перевищує 0,5 Гц. Третій етап включає обґрунтування процедури одержання значень частотних характеристик оператора та його статичного параметра. Частотні характеристики оператора на фіксованій частоті та величина його статичного параметра одержані чисельним шляхом. Ця процедура основана на використання масиву даних, який одержаний шляхом вимірювань значень перехідної функції оператора через фіксовані інтервали часу. Для одержання масиву даних використовується інтерактивна установка-аналог, яка може виконувати функції тренажера. Інтервали часу обираються згідно до теореми Котельнікова – Найквіста – Шеннона. На останньому етапі надається опис процедури визначення динамічних параметрів оператора мобільної пожежної установки на базі сігвею. Показано, що похибка визначення динамічних параметрів оператора мобільної пожежної установки не перевищує 9,0 %, якщо похибка визначення його частотних характеристик на частоті 2,5 с-1 не перевищує 2,0 

A fluorescent microspheres-based microfluidic test system for the detection of immunoglobulin G to SARS-CoV-2

Background: The pandemic of the new coronavirus infection, COVID-19, is currently ongoing in the world. Over the years, the pathogen, SARS-CoV-2, has undergone a series of mutational genome changes, which has led to the spread of various genetic variants of the virus. Meanwhile, the methods used to diagnose SARS-CoV-2, to establish the disease stage and to assess the immunity, are nonspecific to SARS-CoV-2 variants and time-consumable. Thus, the development of new methods for diagnosing COVID-19, as well as their implementation in practice, is currently an important direction. In particular, application of systems based on chemically modified fluorescent microspheres (with a multiplex assay for target protein molecules) opens great opportunities. Aim: development of a microfluidic diagnostic test system based on fluorescent microspheres for the specific detection of immunoglobulins G (IgG) to SARS-CoV-2. Methods: A collection of human serum samples was characterized using enzyme-linked immunosorbent assay (ELISA) and commercially available reagent kits. IgG to SARS-CoV-2 in the human serum were detected by the developed immunofluorescent method using microspheres containing the chemically immobilized RBD fragment of the SARS-CoV-2 (Kappa variant) viral S-protein. Results: The level of IgG in the blood serum of recovered volunteers was 9-300 times higher than that in apparently healthy volunteers, according to ELISA (p0.001). Conjugates of fluorescent microspheres with the RBD-fragment of the S-protein, capable of specifically binding IgG from the blood serum, have been obtained. The immune complexes formation was confirmed by the fluorescence microscopy data; the fluorescence intensity of secondary antibodies in the immune complexes formed on the surface of microspheres was proportional to the content of IgG (r 0.963). The test system had a good predictive value (AUC 70.3%). Conclusion: A test system has been developed, based on fluorescent microspheres containing the immobilized RBD fragment of the SARS-CoV-2 S-protein, for the immunofluorescent detection of IgG in the human blood serum. When testing the system on samples with different levels of IgG to SARS-CoV-2, its prognostic value was shown. The obtained results allow us to present the test system as a method to assess the level of immunoglobulins to SARS-CoV-2 in the human blood serum for the implementation in clinical practice. The test system can also be integrated into various microfluidic systems to create chips and devices for the point-of-care diagnostics

Thin layer fluorescence microscopy based on one-dimensional photonic crystal

A new method of specimen illumination for wide-field fluorescence microscopy has been presented. This method allows to excite the fluorescence in a thin near-surface layer of the studied object. As a result, the captured images have greater contrast and signal-to-background ratio in comparison with the epifluorescence ones. The long-range surface waves in one-dimensional photonic crystal have been used to localize the electromagnetic field exciting the fluorescence. An experimental setup has been created to excite the surface waves and obtain images of the objects from the near-surface layer. For an illustration of the possibilities of our method, we conducted several experiments with specimens that are typical for fluorescence microscopy, such as bacteria and eukaryotic cells

Au/Ag-containing DNA-based nanowires

Direct conductivity measurements of thin uniform gold-coated DNA nanowires are presented. Gold-coated DNA conductive wires deposited on a mica surface are visualized by SEM and conductivity of the wires are measured using nanomanipulators built inside the microscope. The measurements show that the conductivity is limited by defects, and the thicker the coating the higher the conductivity of the wires. These gold-coated DNA nanowires are promising candidates for molecular electronics. DNA-base nanomaterial to be used in new DNA-based molecular electronics

Au/Ag-containing DNA-based nanowires

Direct conductivity measurements of thin uniform gold-coated DNA nanowires are presented. Gold-coated DNA conductive wires deposited on a mica surface are visualized by SEM and conductivity of the wires are measured using nanomanipulators built inside the microscope. The measurements show that the conductivity is limited by defects, and the thicker the coating the higher the conductivity of the wires. These gold-coated DNA nanowires are promising candidates for molecular electronics. DNA-base nanomaterial to be used in new DNA-based molecular electronics

Registration of long-range surface plasmon resonance by angle-scanning feedback and its implementation for optical hydrogen sensing

An optical technique devised for the detection of the ultrasharp angular resonance of long-range surface plasmons (LRSPs) is described. The LRSPs propagate along an 8 nm-thick palladium (Pd) film deposited on a one- dimensional photonic crystal structure and bordering a gas environment at another Pd film interface. At such a small metal film thickness, the scattering attenuation losses prevail over dissipation losses inside the film and we use this scattering as an input signal to pick up the angle of the surface plasmon resonance by a closed feedback loop via an angle-scanning piezomirror. As an implementation of this technique, we detected a 0.5% hydrogen concentration in nitrogen at room temperature with a signal/noise ratio of approximately 100 and response and recovery times of about 5 and 15 s, respectively

Developing A Method for Determining the Dynamic Parameters of the Operator of A Mobile Fire Engine Based on A Segway

A method for determining the dynamic parameters of the operator of a mobile fire engine based on a segway, which fully characterize its dynamic properties – delay time and inertia was developed. The development of the method includes four stages. At the first stage, the problem of obtaining analytical relationships for determining the dynamic parameters of the operator is solved. These relationships include the frequency characteristics of the operator at a fixed frequency and its static parameter. At the second stage, the choice of a fixed frequency is substantiated using a criterion that minimizes errors in determining the dynamic parameters. It is shown that the fixed frequency for the characteristic parameters of the operator does not exceed 0.5 Hz. The third stage includes substantiation of the procedure for determining the frequency characteristics of the operator and its static parameter. The frequency characteristics of the operator at a fixed frequency and its static parameter are determined numerically. This procedure is based on using the data obtained by measuring the values of the operator's transfer function at fixed time intervals. To obtain data, an interactive analog engine is used, which can also perform the functions of a simulator. The time intervals are chosen according to the Kotelnikov-Nyquist-Shannon theorem. At the last stage, the procedure for determining the dynamic parameters of the operator of a segway-based mobile fire engine is described. It is shown that the error in determining the dynamic parameters of the operator of a mobile fire engine does not exceed 9.0 %, if the error in determining its frequency characteristics at a frequency of 2.5 s–1 does not exceed 2.0

Size-dependent hydrogen uptake behavior of Pd nanoparticles revealed by photonic crystal surface waves

We present an optical method of study of nanoparticle properties using photonic crystal surface waves. Palladium nanoparticles were deposited on a surface of a one-dimensional photonic crystal, which supports the propagation of p-polarized optical surface waves. The changes in the nanoparticle properties, such as its dimension and refractive index, were monitored through angle interrogation of the photonic crystal surface waves. The interaction of palladium nanoparticles with hydrogen was detected with this method. The size-different hydrogen uptake behavior by 2 and 6 nm diameter Pd nanoparticles results in qualitatively different response of the optical signal, viz., in the different signs of such a response. This not only confirms the absence of the alpha- to beta-phase transformation for the smallest palladium nanoparticles, but is a plausible indication that hydrogen donates its electrons to a collective electron band of the metal. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3690085

The Elaboration of Effective Coatings for Photonic Crystal Chips in Optical Biosensors

Here, we propose and study several types of quartz surface coatings designed for the high-performance sorption of biomolecules and their subsequent detection by a photonic crystal surface mode (PC SM) biosensor. The deposition and sorption of biomolecules are revealed by analyzing changes in the propagation parameters of optical modes on the surface of a photonic crystal (PC). The method makes it possible to measure molecular and cellular affinity interactions in real time by independently recording the values of the angle of total internal reflection and the angle of excitation of the surface wave on the surface of the PC. A series of dextrans with various anchor groups (aldehyde, carboxy, epoxy) suitable for binding with bioligands have been studied. We have carried out comparative experiments with dextrans with other molecular weights. The results confirmed that dextran with a Mw of 500 kDa and anchor epoxy groups have a promising potential as a matrix for the detection of proteins in optical biosensors. The proposed approach would make it possible to enhance the sensitivity of the PC SM biosensor and also permit studying the binding process of low molecular weight molecules in real time