The object of study is implementation of normalizing converters based on neural network methods to increase the accuracy of temperature measurements with Chromel-Alumel thermocouples (Type K). Detailed analysis of physical and technical limitations of Type K thermocouples is conducted including nonlinearity of characteristic curve, irreversible parameters drift during high-temperature exploitation, reversible instability (hysteresis), as well as influence of cold junction temperature. Traditional linearization and error compensation methods are compared with innovative approaches based on artificial neural networks. Multilayer perceptrons (MLPs) for static error compensation and recurrent networks with long short-term memory (LSTM) for dynamic effects accounting are validated as the most effective architectures for solving the stated problems. The study demonstrates that neural network methods enable complex adaptive error compensation that can not be achieved by traditional methods, which paves the way for the development of a new generation of intelligent temperature sensors. It is concluded that type K thermocouples are highly competitive and promising in modern industrial systems in an Industry 4.0 environment, provided they are equipped with intelligent neural network converters.

Genetic analysis in microfluidic devices commonly relies on detection of fluorescence intensity from dyes bound to DNA fragments. Aim of this work was to develop an experimental setup and a method for obtaining fluorescence intensity of liquids placed in microfluidic chips by analyzing digital fluorescence images under light excitation. This article describes an experimental setup for detection of fluorescence signal from sample placed into reaction chamber of microfluidic chips with a 25 × 40 mm field of view. The system directs excitation radiation from an LED (λavg = 480 nm, P = 3 W, Umax = 6 V, Imax = 0.6 A) through a bandpass filter (467–498 nm) and a lens onto the surface of a microfluidic chip. The selected parameters of the system enable efficient excitation of fluorescent dyes without overlapping their emission spectrum. Experiments were performed using fluorescein isothiocyanate solutions of different concentrations. Comparison of the signal-to-noise ratio values of the presented experimental setup with that of a commercially available realtime polymerase chain reaction device (ANK-48) has been carried out. The key advantages of the proposed system are its ability to perform full-area fluorescence detection on the microfluidic chip and its flexibility in terms of chip topology, i. e., the ability to work using chips of various designs and geometries.

Nowadays development and production of microelectromechanical systems is one of the most promising directions in the world's economy. One of the innovative fields in the development of microsystems is integration of optical devices as measuring transducers. Goal of the paper is optimization of the optical measuring transducer geometry for microelectromechanical pressure sensor which provides a required value and linearity of the optical transmission coefficient. Microelectromechanical pressure sensor comprises the optical measuring transducer represented by a pair of waveguides that form an optical directional coupler. Linearity of the optical transmission coefficient of the transducer is provided by the selection of the initial gap between the waveguides at the linear section of the curve representing dependence of the optical transmission coefficient on the gap. Calculation of the required characteristics of such transducer requires a combination of the Finite-difference time-domain method and the mode overlapping method. This allows calculating the magnitude of the optical transmission coefficient for different geometric parameters of the transducer. Two models of the directional coupler with silicon and silicon nitride waveguides were used to determine dependencies of the transducer's optical transmission coefficient on the optical coupling length and the waveguide bending radius. The data obtained were used to plot the dependencies of the transmission coefficient on the gap between the waveguide for both models. The plots show the optimal initial gaps and the length of the linear section. The results allow designing a device with predetermined working section at which the optical measuring transducer can measure membrane displacements that are linearly proportional to an acting pressure. Such working section is characterized by the initial gap in the middle of the linear section that amounts to 500 nm for silicon waveguides and 600 nm for silicon nitride ones. The linear section of the transducer's transmission characteristic for the waveguides of both types is estimated as ±80 nm in relation to the initial gap. In this section, the optical transmission coefficient of the transducer with silicon waveguides alters from 0 to 0.86 which corresponds to a value of 5.375‧106 m-1. For the waveguide with silicon nitride waveguides the coefficient varies from 0.09 to 0.53 which corresponds to a value of 2.75‧106 m-1. The computer aided analysis methods allow for determining the optimal geometry of the evanescent coupling-based measuring transducer that is used in the microelectromechanical pressure sensor. The presented models of two transducers with two waveguides made of different materials demonstrate different characteristics. The optimal parameters for each of the models are achieved at different waveguide bending radii and optical coupling lengths.

Evaluation of electrical signals’ level with various shapes, such as sinusoidal or rectangular, pulse trains, random, etc., is most often carried out based on the root-mean-square value of voltage and the peak factor. Analysis performed showed absence of mass-produced domestic high-precision measuring converters of alternating voltage to direct current voltage based on the root-mean-square value, intended primarily for use in alternating current voltmeters and high-frequency voltage calibrators. Aim of this work was to develop, manufacture and experimentally study a prototype measuring converter of alternating voltage to direct current voltage for processing sinusoidal signals with a frequency from 1 kHz to 50 MHz and arbitrary signals with a peak factor equal to 5. Article describes design and circuitry features of the created prototype and of its characteristics measurements’ results. The developed prototype contains a measuring converter of alternating voltage to direct current voltage at the root-mean-square level with a thermoelectric converter microassembly, a broadband amplifier with an eight-fold gain, a set of electronically commutated scaling voltage amplifiers with a transmission coefficient equal to 1.36; 2.15; 4.7. The prototype makes it possible to convert a sinusoidal signal with a root-mean-square voltage in the range from 4.7 mV to 2 V and a frequency from 1 kHz to 50 MHz into direct current voltage with an error of less than ± 4 %, and error in converting a rectangular signal with a peak factor in the range from 1 to 5 does not exceed ± 0.2 %. The measured error of the prototype is comparable to the error of the measuring instruments used, therefore the actual error of the prototype is possibly smaller. In addition, by reducing the range of voltages and/or frequencies of the recorded signals the error of the measuring converter can be minimized by optimally selecting the connected scaling amplifiers.

Development of rifle electronic simulators (i.e. for hand weapons and not using ammunition) is an important task, since the production of any type of small arms, according to regulatory documents, also requires the production of a simulator to instill aiming and firing skills. The developing family of electronic shooting simulators "STrIzh" includes three publicly available levels for self-assembly: initial, basic and virtual. Structural diagrams of aiming point recorders and entry-level weapon simulators are given and a technique for self-assembly of the simulator from publicly available components is developed: laptop, webcam, weapon models, infrared LEDs. Several types of trigger sensors have been developed with a recommendation to use a touch button (especially for a machine gun). New approaches to estimation of mathematical models’ error for aiming point recorders are proposed and new modified mathematical models are also tested in order to minimize the number of calibration points which is important during manual adjustment. Invariance of mathematical models from the firing distance using the second infrared LED and correction of coordinates by using this LED was checked, its performance in a small range of distance changes was shown. Orientation to initial shooting training requires constant tracking and analysis of the aiming trajectory with the issuance of instructions for adjusting the grip-aiming-holding-descent, and therefore high-speed webcams. The studies of the error in determining the aiming point for four types of mock-ups of the simulator showed that the subjective component (the ocular method of aiming during calibration and verification) makes the most significant contribution to the error and it is recommended that the calibration of the mock-up be carried out only by experienced users necessarily from the stop and using the trigger sensor.

Tissue respiration is a multistage biochemical process during which cells obtain energy through the oxidation of organic substances. Studying this process is essential for understanding pathogenesis of many diseases. Aim of this study was to improve the method for studying tissue respiration of biological samples by developing and implementing a polarographic cell made from epoxy resin. The polarographic cell consists of a housing and an internal chamber for introducing biological samples and substances. The upper part of the housing contains two holes of different diameters for insertion biological samples into the internal chamber and allowing the free exit of the modified fluid volume from the chamber of the polarographic cell. A thermostatic tube made from medical-grade polyvinyl chloride is located in the lower part of the housing. The thermostatic tube ends are exposed and used for connection to the external circuit of a water thermostat. For operation, a liquid medium (buffer solution) and a biological sample are added to the internal chamber of a cell placed on a magnetic stirrer. An oxygen electrode connected to a multichannel system is also installed. The oxygen-dependent current is recorded using the Record 4-usb software. The optimal temperature in the chamber is maintained by a water thermostat. After the experiment is completed, the liquid containing tissues is removed, and the cell is washed and dried. The performance test results of the new polarographic cell, obtained in a study of the oxygen consumption rate of intact mouse small intestinal tissue fragments using the oxidative phosphorylation uncoupler 2,4-dinitrophenol, are comparable to typical polarographic oxygen uptake curves described in standard textbooks. The developed epoxy resin polarographic cell could become a cost-effective alternative to expensive equipment, ensuring reliable and reproducible results. The use of this device will expand the availability of this technique in medical and scientific institutions and will contribute to the improvement of diagnostic and pharmacological research. Its ease of use, low cost, and high data reproducibility make the proposed cell a promising tool for fundamental and applied biomedical research.

Modern radiation therapy requires reproducible dose delivery to superficial and near surface structures. An important source of uncertainty is the loss of contact between the bolus and the patient’s skin, leading to air gaps at the bolus–skin interface. The aim of this study was to assess the impact of bolus–phantom interface irregularities on dose distribution. A dedicated methodology was developed, combining Gafchromic EBT3 film dosimetry, ionization chamber measurements, and dose calculations in the Eclipse treatment planning system. Air gaps of 0–5 mm were found to increase the surface dose by up to + 15 %, whereas gaps larger than 5 mm reduced it by up to –23 %; a 10 mm bolus provided more stable dose coverage than a 5 mm bolus. These findings emphasize the need to control bolus–skin contact in treatment planning and quality assurance procedures in radiation therapy.

Study of medical and biological objects poses fundamentally new challenges for scanning probe microscopy methods, as the assessment of living systems requires a method to be not only high-resolution but also high-speed, enabling long-term dynamic observations in the most physiologically relevant environment with minimal mechanical impact on cells. Aim of this article was to demonstrate limitations of atomic force microscopy in study of medical and biological objects, to describe the operating principle of scanning ion-conductance microscopy and scanning modes for obtaining dynamic scans, and a method for assessing cell stiffness without direct contact between the probe (nanopipette) and the sample (cell). Main advantages of scanning ion-conductance microscopy for medical and biological research are outlined, along with the design features of the microscope that enable these advantages. An example of live cells (vascular endothelial cells and buccal epithelial cell) scanned using scanning ion conductance microscopy is provided including surface stiffness distribution maps of the cells.

Reliable determination of the tip-surface contact in atomic force microscopy measurements is necessary for structural and physico-mechanical analysis of the surface properties. Transition from non-contact interaction to contact one during experiments in air environment is accompanied by a rapid jump of the tip to the surface. High velocity of the tip movement in the area of non-contact interaction and the relatively low rate of the atomic force microscopy data capture do not allow determining of the onset of contact from the points of the force curve especially in the case of a deformable surface. The proposed solution is to use machine learning algorithms trained on model results. The interaction of the tip with the surface was modeled using a harmonic oscillator varying parameters of the probe, the material, and the experiment. As a result deflection of the probe in the moment of contact is predicted using input experimental parameters. Use of the developed algorithms is demonstrated by treating the results of the indentation of polyethylene. The obtained contact deflections are significantly differ from the available points of the experimental curves.