Results Of Experimental Research Research Articles

The Effect of Pulsed Electromagnetic Field (PEMF) on Microvascular Autonomic Movement

This article aims to deeply explore the effects of Pulsed Electromagnetic Field (PEMF) acupoint stimulation on the autonomic movement of microvessels. Through a comprehensive analysis of related studies, the characteristics and mechanisms of action of PEMF are elaborated, and the physiological basis and importance of microvascular autonomic movement are introduced in detail. Combining a large number of experimental research results, the effects of PEMF on microvascular autonomic movement in various aspects are discussed, including the effects on vascular endothelial cells, smooth muscle cells, as well as the impact on hemorheology and microcirculation. At the same time, the potential and prospects of PEMF in clinical applications are analyzed, and prospects for future research directions are proposed.

Traceology suggests an unexpected use of antler cheekpieces from the Early Iron Age site at Gzin, Poland

Archaeological data confirm the widespread use of horse tack throughout the North European Bronze Age and the succeeding Hallstatt period in an inventory that included metal cheekpieces, phalerae, rein-knobs and other horse-related accessories. Similar usage has been assumed in the region of northern Poland, which has also furnished evidence for the use of horse gear accessories made of antler. This paper reports the results of traceological, isotopic and experimental research on three antler cheekpieces found at the Early Iron Age stronghold of Gzin in northern Poland and relates them further with archaeological and ethnographic patterns of horse exploitation. The results indicate that the artefacts from Gzin have rare comparanda and are isotopically consistent with the δ18Ow range of the site location, which can both be taken as evidence of their local origin. Moreover, traceological and experimental evidence from this study places the function and use of the analysed objects into a new light, undermining their use for horseback riding and suggesting that they were employed as cheekpiece coverings. Combined with the ethnographic record, ceramic iconography and archaeolinguistics, our findings fuel a discussion of deer valorisation during the Lusatian period in Poland, showing that the cheekpieces from Gzin may have served as elements of deer headgear.

Dynamic processes in current sheets and experimental laboratory astrophysics

The results of experimental research of the dynamics of current sheets, which are formed in laboratory experiments at the IOF RAS, are presented as a brief review. It is shown that the most significant features of phenomena like solar flares can be reproduced in laboratory conditions. These features include the relatively slow accumulation of the magnetic energy in the course of the current sheet formation, the rapid release of the energy during the disruption of the current sheet, acceleration of plasma flows, ultrafast plasma heating, and effective particle’s acceleration. A qualitative similarity has been established between the basic characteristics of current sheets in the tail region of the Earth’s magnetosphere and in laboratory conditions. A comparison of a number of fundamental dimensionless parameters indicates the possibility of quantitative laboratory modeling of processes occurring in the magnetosphere. It is concluded that experimental research of the dynamics of current sheets and magnetic reconnection processes represent one of the promising areas of the laboratory astrophysics.

Load-bearing capacity of single and multi-anchor connections – theory vs results of experimental research (part 1)

Load-bearing capacity of single and multi-anchor connections – theory vs results of experimental research (part 1)

Analysing the Bioactive Compound of Earthworm Pheretima Javanica Extract by Using Gas Chromatography Mass Spectrum

Research Based Learning (RBL) is a learning method that uses contextual learning, authentic learning, problem solving, cooperative learning, hands on and minds on learning and inquiry learning. The STEM approach in learning is expected to provide meaning to students through the systematic integration of research-based knowledge, concepts and skills. STEM design begin with the identification of social problems. The social issue of typhoid fever cases caused by Salmonella enterica Typhi bacteria with a high mortality rate in the world is a public health problem. The existence of Pheretima javanica which is abundant in the environment can be utilized by conducting antibacterial activity testing and analysis of bioactive compounds by students on the form of the extract. This research is a development research carried out with the aim of developing a product and also a qualitative descriptive research which serves to provide an overview of the object. The steps in carrying out these tests were identified as part of learning that hone creative thinking skills. The results of the class experimental research showed that the N-Gain score was 0.8, which is in the high category. These results show that the application of developing problem-based learning tools with a STEM approach is effective. Learning outcomes contribute to the effort to find alternative drugs that are effective and do not cause resistance. In addition, students also produce scientific articles as learning products. This paper has implications for STEM integrated research-based learning.

The Influence of the Parameters of the Skew Rolling Process for Bimetallic Elements on the Mechanical Properties and Structure of Materials.

This paper presents selected results of theoretical and experimental research into the manufacture of axisymmetric bimetallic components using three-tool skew rolling technology. In the tests, it was assumed that the outer layer would be a material intended for heat treatment. However, low-carbon steel was used for the core. Experimental investigations were carried out in an innovative CNC skew rolling mill. Tests were carried out at different technological parameters of the process. In addition, the geometric parameters of the billet and the way it was heated were analyzed in relation to the quality of the resulting weld between the two materials. The quality of the weld was assessed based on metallographic observation and on strength tests (shear method). On the other hand, theoretical studies were based on numerical modeling (FEM). The numerical analysis made it possible to determine the distribution of temperature, deformation and stress in the rolling bimetallic component. The results obtained indicated that it is possible to produce bimetallic materials from the proposed steel grades. In addition, a significant effect of the method of heating the billet in the chamber furnace on the microstructure in the joining zone and the shear strength was found. There was an increase in Rc strength of about 35% when using oxidation protection. The results indicated better strength when the billet is rolling with a smaller outer layer thickness (about 50 MPa). This was confirmed by the results obtained from the FEM analysis, which indicated higher values of plastic strain and the occurrence of higher compressive stresses in the near-surface zones of the rolled bimetallic forging, both of which facilitate the welding process. From the temperature distribution (in the range of (600-1200) °C) obtained during the rolling of the bimetal forging, it can be seen that contact with cold tools does not affect the temperature in the welding zone.

Numerical simulation study on the impact of convective heat transfer on lithium battery air cooling thermal model

To enhance the accuracy of lithium battery thermal models, this study investigates the impact of temperature-dependent convective heat transfer coefficients on the battery’s air cooling and heat dissipation model, based on the sweeping in-line robs bundle method proposed by Zukauskas. By calculating and fitting the relationship between the convective heat transfer coefficient and temperature at flow rates of 0.05 m/s, 0.15 m/s, 0.25 m/s, and 0.35 m/s, it was found that the relationship is complex. An electrochemical-thermal coupling model was established using the operational characteristics of lithium batteries, and a thermal runaway reaction kinetics model was created using isothermal thermal runaway experiments and least squares optimization. The temperature-dependent convective heat transfer coefficient was then integrated into both models. Numerical simulations revealed that during normal discharge, the maximum temperature difference in the battery when the convective heat transfer coefficient is a function of temperature is less than 1 % compared to when it is constant. However, in the high-temperature thermal runaway model, the impact of temperature-dependent convective heat transfer coefficients on the thermal runaway critical parameters is minimal at flow rates of 0.05 m/s and 0.15 m/s. When the flow rate increases to 0.25 m/s and 0.35 m/s, the impact on the trigger time of thermal runaway is 17.34 % and 18.07 %, respectively. Experimental validation and research results indicate that the temperature effect on the convective heat transfer coefficient should be considered in high-temperature thermal runaway and thermal management models to calculate the convective heat transfer more accurately within the battery pack, improving model accuracy and reducing the risks of thermal runaway.

Establishing patterns of change in the coefficients of reflection, transmission, and dissipation of wave energy depending on parameters of a permeable vertical wall

The object of research is permeable vertical walls (breakwaters) with different degrees of permeability. This paper reports the results of experimental research into the interaction of gravity waves with models of permeable vertical walls (breakwaters), which were formed from cylindrical piles of circular cross-section. With the help of visual and instrumental studies, the features of interaction of surface gravity waves with permeable vertical walls of different permeability have been identified. The degree of wave transformation by these walls was also determined in the form of reflection, transmission, and dissipation coefficients of wave energy. It was established that with a decrease in the permeability of the vertical wall and an increase in the steepness of the initial wave and a decrease in its period, the height of the reflected wave increased. The pattern of the transmitted wave height had the opposite trend. It was determined that the wave reflection coefficient increased with a decrease in the permeability of the vertical wall and the steepness of the initial wave. The wave transmission coefficient had the opposite trend, namely, it increased with increasing wall permeability and with decreasing steepness of the initial wave. The gravity wave energy dissipation coefficient decreased with increasing vertical wall permeability, but for waves with a significant steepness hi/λ>0.038, a decrease in the wave energy dissipation coefficient was observed for walls with low permeability and the appearance of extreme values of this coefficient. Thus, features in the interaction of surface gravity waves with permeable vertical walls (breakwaters) of different permeability have been researched and the degree of wave transformation by these walls has been determined, which could make it possible to effectively design and operate permeable vertical walls as coastal protection structures

Inlet injection as an alternative, simplified method of hydrogen application in a miniature gas turbine

Hydrogen-powered gas turbines have great potential, because, among other things, they allow the elimination of the use of fuels containing carbon in their composition, which involves the elimination of CO2 emissions, which are a product of the combustion of hydrocarbon fuels. The paper presents the results of experimental research conducted on a miniature gas turbine co-powered by hydrogen gas. The aim of the research was to demonstrate the impact of the addition of hydrogen on the operation of the unit and exhaust gas emissions during hydrogen application in a way that does not require engine modification. This was accomplished by applying hydrogen gas through the turbine inlet. Hydrogen gas accounted for up to 0.91% of the total volume of gas flowing through the compressor, which resulted in hydrogen contributing almost 10% of the energy supplied to the engine in the form of fuel. The research focused on measuring fuel consumption, thrust, and temperature, as well as the composition of exhaust gases. The emission of carbon monoxide, nitrogen oxides and the concentration of oxygen and carbon dioxide were measured. The addition of hydrogen resulted in a reduction of the total mass of fuel consumed by over 18%. It led to a significant decrease in the temperature behind the combustion chamber with an increase in the amount of hydrogen applied. The addition of hydrogen also resulted in a reduction in CO2 concentration in exhaust gases by more than 30%, but at the same time, an increase in NOx emissions was recorded. The obtained results were compared with the results of tests presented in the literature, in which hydrogen was supplied to units of analogous structure in a classical way, i.e. directly to the combustion chamber.

About the rational choice of the damper shape for an ultrasonic piezoelectric transducer

The results of the study on the influence of the geometric shape of the damper on its effectiveness and the overall efficiency of the radiation-reception system are presented. One of the possible forms of the damper is considered, where it is shaped like a truncated cone, and its generatrix has an inclination angle relative to the plane of the piezoplate. A criterion for evaluating the efficiency of the damper’s operation is proposed. The study includes the results of computational-theoretical (using the finite element method) and experimental research on the influence of the incline angle of the damper’s generatrix on the signal reflected from its rear part. The inclination angle of the generatrix, at which the minimum of parasitic signals is achieved, is determined. The radiation-reception system is investigated under water loading, and a satisfactory agreement between the theoretical and experimental results is noted.

Modelling of phase transformations occurring in the process of austempered ductile iron manufacturing

The paper presents mathematical models and their implementation in C # language describing the phase transformations occurring in the process of austempered ductile iron (ADI) manufacture. The research includes two main stages: austenitization and isothermal holding at the bainitic range. The influence of free energy of austenite and ferrite on transformations was taken into account. Parameters of models were identified based on inverse analysis and experimental research. As part of the research, verification and validation of the developed models was carried out based on the results of experimental research. The tool developed and implemented enables the analysis of phase transformations occurring during heat treatment with isothermal holding of ductile iron with Ni addition.

HE EFFECT OF LOADS SUPERPOSITION ON TECHNICAL STRUCTURES, ENVIRONMENT AND LIVING ORGANISMS

The current state of calculation the result of the superposition of loads, or their effects, on a material body is analyzed. The limits of the current calculation methods, based on strength theories, in the case of technical structures are shown. The results of experimental research that refer, in general, to the superposition of two loads of the same nature and without addressing problems of loads of a different nature (mechanical, chemical, electrical, magnetic, radioactive etc.), in the case of technical structures and the environment is analyzed. Starting from the principle of critical energy, which is based on the concepts of the total specific energies’ participation of the loads and of the critical participation, general relations are deduced for these concepts, in the case of the nonlinear behavior of matter, as a function of power. These results are applied to the calculation of the superposition of loads of different nature on a technical structure, the environment and living organisms, taking into account the deterioration of matter. The influence of the loading speed (static, shock ...) is taken into account based on the value of the exponent in the behavior law, which was not possible in the previous calculation methods. From the analysis of the results obtained in the paper, it is found the utility and the high degree of generality of the principle of critical energy and of the concept of the specific energy participation.

Determining infrared radiation intensity characteristics for the exhaust manifold of gas turbine engine ТВ3-117 in МІ-8МSB-B helicopter

The object of this study is the screen-exhaust device in the TV3-117 engine of the Mi-8MSB-B helicopter. To reduce visibility in the thermal range, a system of mixing hot engine exhaust gases with ambient air is used; this technique makes it possible to reduce the infrared radiation of engines. For this purpose, a new sample of screen-exhaust device was designed for testing. A thermal imaging survey of the helicopter was conducted. Three variants of thermal images were acquired: a helicopter without installation of a thermal visibility reduction system, a helicopter with standard exhaust shields installed, and a helicopter with newly developed shield exhaust devices installed. Based on the obtained experimental results, the characteristics of the intensity of infrared radiation were determined for three variants of research in the range of thermal waves of 3–5 μm. The study uses a comprehensive approach to solving the tasks, which includes a statistical analysis of known and promising ways to protect a helicopter from guided missiles with infrared homing heads based on reduced radiation forces and a theoretical method for calculating flow and temperature fields. The advantages of placing the section of the exhaust channel of the designed screen-exhaust device in the horizontal plane for complete shielding of infrared radiation in the lower hemisphere have been experimentally proven. The benefits of directing the flow of exhaust gases from the screen-exhaust device into the space above the helicopter propeller and dividing this flow into four separate flows were shown. The results of experimental research could be used to design new or improve existing screen-exhaust devices by the developers of military aviation

Odors Adsorption in Zeolites Including Natural Clinoptilolite: Theoretical and Experimental Studies.

This publication presents the results of combined theoretical and experimental research for the potential use of natural clinoptilolite zeolite (CLI) as an odor-adsorbing material. In this study of adsorption capacity, CLI of various granulation was used and its modifications were made by ion exchange using Sn and Fe metals to check whether the presence of metals as potential active centers does not lead to catalytic processes and may lead to enhanced absorption of odorous substances through their adsorption on the created metallic forms. Additionally, in order to increase the specific surface area, modifications were made in the form of hierarchization in an acidic environment using hydrochloric acid to also create the hydrogen form of zeolite and thus also check how the material behaves as an adsorbent. To compare the effect of CLI as a sorption material, synthetic zeolite MFI was also used-as a sodium form and after the introduction of metals (Sn, Fe). The above materials were subjected to adsorption measurements using odorous substances (including acetaldehyde, dimethylamine, pentanoic acid and octanoic acid). Based on the measurements performed, the most advantageous material that traps odorants is a natural material-clinoptilolite. Depending on the faction, its ability varies for different compounds. In the case of acetaldehyde, an effective material is clinoptilolite with a grain size of up to 2 mm. In the case of carboxylic acids, it is material after hierarchization with a fraction of 3-4 mm. In the case of theoretical calculations, information was obtained to show that metallic centers are more stable above oxygen, which is associated with the skeletal aluminum in clinoptilolite.

Ignition energy, explosion flame propagation, and particle movement process of coal dust cloud in vertical Hartmann tube

To discuss the ignition energy, explosion flame propagation, and particle movement process of coal dust in vertical glass tube, experimental analysis and numerical simulation methods are used to carry out research. The experimental research results show that the optimal ignition delay time is 1 s, under this condition, the dust cloud near the ignition electrode has the highest turbulence, making it easier to ignite. When the dust cloud mass concentration is 2500 g/m3, the ignition energy is the smallest, resulting in the highest risk of explosion. The simulation results show that the propagation speed of flame is 4 m/s, due to the small amount of suspended dust used, the intensity of the explosion is not significant. The further away from the explosion source, the more energy is lost, the lower the temperature of the flame. Within 30∼50 ms after the ignition, the temperature near the explosion source rapidly increases, from 900 K to 1300 K. During the period of 0.2–0.5 s after dust injection, most particles move upwards along the tube. At 1 s after the dust injection, most particles move downwards and gather near the ignition electrode, forming a suspended dust cloud that is easily ignited, which is consistent with the optimal ignition delay time of 1 s obtained from the experiment.

Clinical Efficacy and Experimental Research Progress on Traditional Chinese Medicine Moxibustion Therapy in Ovarian Injury

AbstractThis review summarizes the clinical efficacy and experimental research of traditional Chinese medicine (TCM) moxibustion in the intervention of ovarian injury. Clinical and experimental research results have shown that as a nonpharmacological treatment method, Chinese medical moxibustion therapy is of great significance in the treatment of ovarian injuries such as diminished ovarian reserve, polycystic ovarian syndrome, premature ovarian failure, and premature ovarian insufficiency. Moxibustion, heat-sensitive moxibustion, and electroacupuncture have significant effects in improving ovarian function, overall treatment efficacy, pregnancy rate, ovulation rate, and sex hormone levels and have higher safety. Their therapeutic mechanisms have also been demonstrated. In conclusion, TCM moxibustion therapy has a significant effect in the treatment of ovarian injury, providing a new option for the treatment of the ovarian injury.

Behavior of Fatigue Damaged Reinforced Concrete One-Way Slabs Repaired With CFRP Sheets

Abstract The results of experimental research involving nine one-way slabs are detailed in this report. The objective was to investigate the impact of different parameters on the structural performance of these slabs in their absence and with strengthening. Externally bonded CFRP sheets strengthened six of the nine slabs; the three remaining slabs served as control specimens. Before subjecting the specimens to monotonic loading, pre-fatigue damage of 50% and 70% repeated loading was induced. An exhaustive assessment was conducted on each slab, in which it was compared to its control slab. Several crucial elements were incorporated into the evaluation, including the ultimate load capacity, the reason for failure, crack patterns, and load-deflection curves. Examining these metrics was intended to provide insight into the efficacy and structural performance of the employed fortification technology. Compared to unenhanced reinforced concrete slabs (control slab), the highest stresses on slabs supported with bonded CFRP sheets are between 20 and 44% better. Compared to the control slab, an almost 70% reduction in deflection was observed. The flexural performance of compromised reinforced concrete slabs repaired with this technology can be brought up to date and enhanced.

Preliminary microstructural research of clay solid bricks taken from historic buildings located in Poland

The article presents the results of the preliminary experimental research and analysis of the structure of samples of clay solid bricks from six historical buildings erected in Poland in the years 1300 to 1910. Images obtained with a scanning electron microscope; parameters characterizing the pore space of the ceramic material, which were obtained using mercury porosimetry; and chemical composition identified using an energy dispersive X-ray spectroscopy, were analyzed. The test results showed that as the age of the brick increases, the homogeneity of its structure decreases, the chemical composition of all samples is quite similar, and in the tested samples, large disproportions in the percentage of pore width in individual ranges can be observed. An indicator P-index useful in comparing the studied structures was proposed, based on the knowledge of the share of the pores’ width within the adopted ranges.

Modeling of Yb:YAG Laser Beam Caustics and Thermal Phenomena in Laser-Arc Hybrid Welding Process with Phase Transformations in the Solid State.

This paper focuses on the mathematical and numerical modeling of the electric arc + laser beam welding (HLAW) process using an innovative model of the Yb:YAG laser heat source. Laser energy distribution is measured experimentally using a UFF100 analyzer. The results of experimental research, including the beam profile and energetic characteristics of an electric arc, are used in the model. The laser beam description is based on geostatistical kriging interpolation, whereas the electric arc is modeled using Goldak's distribution. Hybrid heat source models are used in numerical algorithms to analyze physical phenomena occurring in the laser-arc hybrid welding process. Thermal phenomena with fluid flow in the fusion zone (FZ) are described by continuum conservation equations. The kinetics of phase transformations in the solid state are determined using Johnson-Mehl-Avrami (JMA) and Koistinen-Marburger (KM) equations. A continuous cooling transformation (CCT) diagram is determined using interpolation functions and experimental research. An experimental dilatometric analysis for the chosen cooling rates is performed to define the start and final temperatures as well as the start and final times of phase transformations. Computer simulations of butt-welding of S355 steel are executed to describe temperature and melted material velocity profiles. The predicted FZ and heat-affected zone (HAZ) are compared to cross-sections of hybrid welded joints, performed using different laser beam focusing. The obtained results confirm the significant influence of the power distribution of the heat source and the laser beam focusing point on the temperature distribution and the characteristic zones of the joint.

Experimental Study of Direct Shear Properties of Anisotropic Reservoir Shale

Understanding the shear mechanical properties of shale reservoirs is of great significance in the study of the formation stability around horizontal shale wells and the propagation and evolution of fractures for shale fracturing. However, the existing direct shear test results are limited due to small sample sizes and low shear rates. Based on previous experimental research results, the mechanical properties of anisotropic reservoir shale in direct shear tests with different experimental conditions were explored in this study. It was found that the shear mode, shear strain rate, and normal stress have a significant impact on the deformation and failure characteristics of shale. The peak shear displacement, peak shear strength, and shear stiffness of shale present an increasing trend of fluctuation, with an increase in the bedding angle. The peak shear strength of shale decreases with an increase in the shear strain rate, and this decrease trend descends with an increase in the shear strain rate. The shape of the shear fracture zone and the shear fracture mode of shale exhibit bedding effect characteristics. The fractal dimension of the shale shear fracture surface morphology shows a trend of fluctuation with the variation in the bedding angle. Further, the shear strain rate was found to play a dominant role in the fractal dimension of the shear fracture surface. The larger shear strain rate strengthens the bedding effect of the roughness for the shear fracture surface morphology. The results of this study provide a theoretical reference for determining the engineering geomechanics characteristics of shale reservoirs.