Microfluidic devices have traditionally focused on liquid fluids because of their superior flow control, but gas integration has been limited due to complexities in compression and diffusion. However, the emergence of thin, permeable membranes (PMs) has transformed this landscape, allowing precise gas control. This perspective explores the integration of gases in microfluidics, focusing on various applications and benefits. The study investigates the development of cellulose acetate flat sheet membranes produced by the phase inversion technique. The optimum concentration of the polymer in dope solution was determined to produce a dense morphology, which was confirmed by SEM analysis. Gas permeation studies reveal CO 2 ‘s superior permeability due to its polarity and molecular size, influencing ideal selectivity across gas pairs.
a Bayesian model is proposed for determining the optimal variant of the MEMS component manufacturing technological process A software tool has been developed to automate this process Calculations are performed using the proposed models and software.
Biosensors are usually prepared from ceramics and polymer composites. The materials PVDF, HA and silver nitrate, have properties that are very suitable for biosensors. Due to its well-known superior ferroelectric characteristics and biocompatibility, polyvinylidene fluoride (PVDF) polymer has been widely used in several applications. Its applicability is restricted by hydroxyapatite’s brittleness and weak bending strength. Numerous formulations for HA and polymer composites have been devised to composite for the mechanical weakness of HA. Because there is so much HA in the final product, HA/polymer composites are very biocompatible. The maximum piezoelectric activity is produced when an appropriate amount of silver is deposited, and silver nitrate has antimicrobial qualities. The non-toxic solvent DMSO (dimethyl sulfoxide) and the solvent casting method for preparing the thin film were chosen for the preparation of the film. The purpose was to study the photostability of the UV absorbtion. SEM was used to examine the samples morphologically. Was presented structure of the biosensor and application area was chosen.
This article provides an analysis overview of metamaterials mechanical properties and characteristics created from+ specialized lattice structures. Specified metamaterials utilize existing topological optimization algorithms and artificial intelligence methods as a core algorithm for matrix structure generation. In review, we use two types of materials with different physical and mechanical parameters that are widely utilized in additive manufacturing industry. The results of the study made it possible to determine the degree of compatibility of the optimization algorithm and the possibility of its use not only in highly specialized areas, but also for solving a wider range of problems and tasks. We obtained analysis results that allowed us to upgrade the algorithm and expand the directions of its application. We received a new way for further automatization, and the algorithm has been adjusted and restructured depending on the set tasks, chosen materials, and external physical parameters. The most optimal results formed the main dataset for further training of the neural network, which forms the future foundation for our future research.
using finite element approximation of electromagnetic wave propagation problem, we have developed and implemented a finite element model of dichroic terahertz filters with complex structure by unit cell approach. Unit cells are considered as waveguides with specific boundary conditions. The model is implemented by COMSOL software system as ready-to-use tool for dichroic terahertz filters design or refinement. Simulation results show excellent agreement with known experimental data.
Currently, the areas of use of robots in general and zoomorphic ones in particular are very diverse. They are used in various fields: from research to social support for elderly and sick people. When creating such robots, scientists face a number of problems. This paper considers the problem of maintaining balance in a four-legged, Spot type robot. A block diagram for balancing a zoomorphic mobile robot of the Spot type has been developed. We have created a balancing system and carried out studies, which show promising results and a quick response to disturbances. As a result, the robot restores balance after all applied disturbances.
This paper explores the task of automatic intracranial hemorrhage (ICH) segmentation based on computer tomography (CT) data, with potential applications in biomedical engineering. The main focus is, on improving segmentation accuracy by incorporating texture enhancement techniques based on fractional order derivatives. The study looks at the segmentation of ICH using U-Net, a deep learning model that is widely used in the field of the segmentation of medical images. The training process employs a parallel algorithm using CUDA technology. Afterwards, an investigation is conducted into a texture enhancement technique that relies on Riesz fractional order derivatives. The goal is to capture intricate details and subtle textures with the potential to enhance segmentation accuracy. To assess the impact of this preprocessing method on the automatic ICH segmentation problem, the U-Net model undergoes retraining and validation. The texture-enhanced images are analyzed to interpret the obtained results. The findings indicate a subtle yet discernible enhancement in accuracy, as gauged by the Jaccard and Dice coefficients. This emphasizes the auspicious potential of the explored texture enhancement method in improving intracranial hemorrhage segmentation within the realm of biomedical engineering.
The article is devoted to the optimization of the radiation characteristics of a linear focusing array, presenting a set of semitransparent inclined elements (mirrors), an excitation source and a final opaque mirror. The geometry of array meets the quasi-optical conditions, and the inclination of the mirrors is given in such a way that the array allows focusing the scattered field in the Frenzel zone and in the far zone. The formation of a directivity pattern (DP) close to the given one, or ensuring the maximum radiation in the given area of angular coordinates, is realized by the selection of reflection and transmission coefficients of the semitransparent array elements. To ensure these requirements, a variational formulation of the optimization problem is given. The maximization of the corresponding functionals is carried out numerically by the methods of successive approximations. Numerical experiments demonstrate a high accuracy of satisfying the requirements for radiation characteristics, this is confirmed by the experimental data as well.
One of the most common types of the military wounds is below-the-knee amputation. A person with such problem needs a dynamic foot to be able to move and perform simple tasks.The bionic foot might be helpful in the nearest future.
Two approaches to constructing a mathematical model of the distribution of nitrogen dioxide concentration in a given area of the city are considered. In the first approach, based on solving the problem of identification with the analysis of interval data, an interval difference equation is obtained. With the second approach, this equation is approximated by a differential equation. The need for such an approach is caused by the fact that, in most cases, the coefficients of the difference equation have no physical content. In contrast, Differential equations are more suitable for describing the physics of a process. Among them, partial differential equations are distinguished, where the coefficients in the equation are the coefficients of diffusion of a harmful substance in atmospheric air at different spatial coordinates.
This study comprehensively analyzes a composite wind turbine blade, designed to fulfill the increasing demand for renewable energy sources. Taking advantage from a mix of glass reinforced vinyl ester, PVC foam, and carbon-epoxy the blade is produced with a sandwich structure that optimizes both lightness and strength. The primary objective is to estimate the dynamic response and structural integrity of the blades within operational conditions. A detailed stress analysis is conducted to evaluate the blade's performance when subjected to gravitational and centrifugal loads, focusing on tip displacement, maximum stress values, and stress distribution through the blade's thickness under various load scenarios. Subsequently, a prestressed eigenfrequency analysis is performed across a spectrum of operating speeds to identify potential vibrational issues. The results are illustrated in a Campbell diagram, which plots the blade's eigenfrequencies against its rotation speed, providing important insight into the structural dynamics and stability of the wind turbine blades. This analysis is crucial for optimizing the design and ensuring the durability and efficiency of wind turbines in harnessing renewable energy.
Medical pipette with electronic control is an important and indispensable modern device. The paper analyzes the importance of the use of regulated electronic medical pipettes in medical and associated fields. Modern approaches to the development of their micro-electromechanical actuator are outlined. Developing an appropriate mathematical model is necessary for improving the design and control system of the electronic medical pipette, which requires the parameters of the micromotor, most of which are missing from the manufacturer's descriptions. At the first stage, a model for a 610 series coreless motor (6 mm diameter, 10 mm - length) for supply voltage (3.0 - 3.7V) was developed and researched using a specialized package for designing and simulating electromechanical systems JMAG Designer. With the help of the model in JMAG Designer, some of the necessary parameters of the coreless motor are determined. At the second stage, an algorithm was developed and practical experimental studies of the 610 series coreless motor were carried out in order to obtain all the necessary parameters for the further development of a high-precision model. Based on the experimental results, the transfer function was obtained, a high-precision model of the coreless motor was developed in MATLAB, and the corresponding current and speed transition processes were obtained, which confirmed the accuracy of the obtained model. The transition process of the current on the model in case supplied with a voltage of 3.7V coincided at the operating point with an error of 8.1%, the speed of rotation of the motor coincided with an error of 5.7%. A model of an electric microdrive based on a coreless motor for an regulated electronic medical pipette was developed and its operation was investigated.
High permeable material is very important for the design of Micro Electro Mechanical Sensors (MEMS), where magnetic flux is used for the measurement. The present article deals with the investigation of the magnetic properties of the electrolyte iron-silicon powder as well as the sintered specimen developed from the same. A customized arrangement is used for the cryogenic cooling of the iron-silicon powder after annealing in the hydrogen environment. A powder with particle size 120 microns is initially heated at 550 degrees C in a tubular furnace in hydrogen environment for one hour. Then it is cooled cryogenically in a vessel jacketed with liquid nitrogen. Magnetic characterization is performed for Fe-Si powder and compacted specimens mad from the powder. To observe initial magnetization curve and B-H loop characteristics, a test set up is developed which uses an electromagnet placed around the specimen. This set up is capable of supplying variable DC current in the electromagnetic coil and measure magnetic flux density at one end of the specimen. The maximum magnetic permeability, remanence, and coercivity of the iron-silicon powder as well as the sintered specimen is determined experimentally. It is observed that cryogenic cooling results in improvement of 30% in maximum permeability without affecting the remanent magnetic flux.
This study uses a straightforward and cost-effective method to present the synthesis, morphological, and structural characterization of hierarchical ZnO/ZnS nanostructures formed on porous silicon substrates. We achieved flower-like crystallites by employing a two-stage synthesis process, showcasing a unique morphology with an increased surface area. Detailed analysis through Raman spectroscopy and X-ray diffraction (XRD) elucidated the heterostructure’s high crystallinity and structural integrity despite inherent lattice mismatches. The study reveals that the flower-like hierarchical morphology, combined with the material’s compositional properties, significantly enhances its physicochemical properties. These findings suggest potential ZnO/ZnS heterostructure applications in various microelectromechanical system (MEMS) technologies, including sensors, photodetectors, and photocatalysts.
This work is devoted to the determination of influence of the internal forces on the propagation of the waves in electromechanical systems. The task is simplified to an inverse problem for the third order hyperbolic equation with the integral overdetermination condition and with the unknown function in the right-hand side of the equation. Some numerical results are presented for viscoelastic medium and for liquid like water with solid parameters. The presented method gives us opportunity to find the precise analytical solutions to the mathematical problems that simulate the wave propagation.
The control system of a robotic mobile platform for movement on orthogonal routes is considered in this paper. To track marking lines on rectilinear segments of the orthogonal routes, a method of changing the direction of the platform movement by changing the speed of rotation of the right and left pairs of the drive wheels without their deviation is proposed. A model to describe the movement of the platform when correcting its trajectory was developed. An electrical scheme of pulse generation for stepper motors is proposed.
A physico-mathematical model is proposed for determining and analyzing the Joule heat behavior in a two-layered tube under the action of a nonstable electromagnetic field. The basic boundary value relations for determination of the electromagnetic field for the considered tube are formulated. The axial constituent of the magnetic field intensity vector is the determining function. It is used a quadratic approximation of this constituent along the radial coordinate in each component layers of the tube and the Laplace transform in time are used for the solution construction. It is found the expressions for this constituent and Joule heat in the component layers of the two-layered tube under the action of a nonstable electromagnetic field. It is studied the time behavior depending on the carrier frequency and the duration of a nonstable electromagnetic action across the thickness of each component layer of the considered constituent of the magnetic field intensity vector and Joule heat.
Micromixer is a crucial component of microfluidics for mixing of various biofluids and biochemicals. In this research work, a numerical investigation of a micromixer using a hybrid actuation approach was conducted for three different micromixer designs. In hybrid actuation approach, acoustic streaming is used as an active approach while hexagonal shape micropillars and triangular wedges are used as passive actuation approach. Three different numerical schemes such as thermoviscous acoustic, laminar flow and transport diluted species are used to solve governing equations. For this purpose, COMSOL Multiphysics is used. The results reveal that the micromixer design with four triangular wedges has a higher mixing performance than other designs. The achieved mixing index of 0.995 for the design with four triangular wedges integrated at sidewall of the channel which is higher value compared to other designs. The improved mixing performance is attributed through increasing acoustic streaming generation. The acquired results can be considered useful for engineers and researchers in the design and modification of micromixers.
The properties of electrical parameters of the MEMS run parts are studied in the paper. The analytical approach is performed for description of the impact of the components of electrical field (EF) on the effects that result in coupling the components of electromagnetic (EM) field and the parts of the MEMS run parts. The self-inductance of two types of microsolenoids is calculated analytically that easy way to modeling and parameter’s optimization of the MEMS run parts, which are the actuators, sensors and so on.
Oil extraction screw presses are widely used in agriculture and food industry. In most cases, they are not equipped with complicated control systems due to the necessity of reducing their price and providing sufficient reliability. Therefore, such presses cannot reach the best efficiency (productivity, performance), while processing different seeds and kernels. The present paper is focused on development of the enhanced control allowing for monitoring the operational parameters of the screw press and adjusting them in accordance with user-defined technologically prescribed ones. The research methodology contains a thorough analysis of the press design and operational peculiarities, and the development of functional (block), circuit, and breadboard diagrams of the control system. In order to verify the initially stated ideas of control strategies, the simulation models of the control systems are implemented in the TinkerCAD and SolidWorks software, and the experimental prototype of the screw press is correspondingly improved. The presented control system and press regulation strategies can be effectively implemented by engineers and technologists while developing new and enhancing existing designs of screw presses.
