Estimation of performance characteristics of a controlled shock-absorber affected by the magnetic field and temperature on rheological properties of the magnetorheological fluid

The mathematical model of MR fluid flow in an annular channel of the MR shock-absorber taking into account forces of dry friction and gas friction in a pneumatic camera, dependence rheological properties of the MR fluid on shear rate, temperature and magnetic flux density is developed. Performance characteristics of the MR shock-absorber (dependences of force on value of control electric signal taking into account of shock-absorber geometry, rod displacement, rheological properties of MR fluid, temperature) are calculated. The analysis of influence of the magnetic field and temperature values on the MR shock-absorber performance characteristics depending on amplitudes and frequencies of piston movement is carried out. The resistance force with growth of magnetic flux density increases 40 times. But the resistance force with growth of temperature from 20°C to 80°C decreases 7 times, in an magnetic field (B= 500 mT), and 2 times, without a field (B= 0 mT)

Design and the main parameters of tube-shaped ultrasound wave guide wire

Cardiovascular diseases are the leading cause of death among people up to 65 years old. One of the most common cardiovascular disease is thrombosis. To remove the blood clot inside the artery, advanced invasive devices are needed. Nevertheless, medicine of today is not technically fully ready to cope with the challenges. Because of that, tube-shaped ultrasound waveguide wire was designed and the main parameters, such as resonant frequency for displacement towards z axis were examined

Air flow pressure drop research of vehicle air filter with different inner liner design

Air filters was designed for air cleaning. They extends automotive and industrial devices life, because it cleans absorbing air from environment. For example it cleans air for internal combustion engines, air compressors, air conditioners and so on [1]. For better air cleaning it is necessary to create air filter housing model and make air flow calculations. Calculation results helps to adapt additional elements for longer air filter element life and better air filtration. During calculations was found one of the best technical solutions for better air filtration. Designed part was produced using 3D printer. Later with assembled filter some measurements and experiments were made. This article presents air flow pressure drop in air filter with different inner liners

Piezoelectric actuation for microfluidic cell sorting

Since the field of microfluidics is vastly improving and developing, and piezoelectric actuators offer good control on a micrometer scale, this work was created as a combination of the two. A microfluidic chip with an embedded piezoelectric actuator was designed and constructed using polydimethylsiloxane as the main material. The chip was experimented on by varying both mechanical and electrical properties. Performance dependencies of volumetric flow rate and input waveform were described and analyzed. Moreover, beneficial phenomena were discovered and analyzed using high-speed microscopy and digital image analysis. A situation where control of microfluidic flow direction could potentially be available was achieved. Other promising results showed new potential applications for piezoelectric actuation in microfluidic systems

Cleaning of the surface contaminated by micro-particles by means of vibrations

This article is about vibration technologies adaptation for polluted surface cleaning. This cleaning method can be adapted in various areas [1-3]. For example, for used automotive air filters cleaning or during operation prolonging their life. Also this method can be used in buildings, because if in house is installed recuperator it is necessary to use air filters. During the exploitation this filters became polluted by contaminant particles. That to increase air filtering quality and prolonging filter life may be used vibration technologies

Mechanism of generation of the flexural vibrations in an ultrasonic waveguide

This article deals with the problem of transfer of ultrasonic vibrations on flexible hub-waveguide system and is a continuation of research in this field [1-3]. The main field of application of flexible hub-waveguides-minimally invasive surgery for treatment of vascular diseases, where they are used to restore patency of blood vessels by destroying blood clots and tromboèmbolov. Thanks to the possibility of elastic deformation of flexible hub-waveguides, they can be delivered through a catheter system to the most remote places of the blood vessels, producing ultrasonic processing of affected sites with minimal surgical intervention. It should be borne in mind that during the work of the PA system can change its own hub-frequency waveguides and frequency generator, and this can lead to beating frequencies, formation of flexural vibrations of a working part, etc. This article therefore tasked to define the conditions of formation of low-frequency oscillations of a bend when passing ultrasonic vibrations of flexible waveguide system

Theoretical and experimental investigation of the tube-shaped waveguide wire

Cardiovascular diseases are the leading cause of death among people up to 65 years old. One of the most common cardiovascular disease is thrombosis. To remove the blood clot inside the artery, usage of advanced invasive mechanical devices is needed. There is a need for the new alternative less risky and hazardous way of arterial thrombosis treatment. This paper presents a new design of a less risky ultrasonic blood vessels cleaning system

IVUS-VH relation to the extent and composition of atherosclerotic plaque and clinical outcome prognosis

Background and aim: Most frequent and generally unpredictable coronary plaque rupture impacts the burden of coronary artery disease but features or signs related to plaque remodeling into the high risk structure are not clearly detectable by using ordinary visualization methods. Till yet there are no evident criteria for additional using IVUS. The aim of the study was to determinate intravascular ultrasound virtual histology (IVUS-VH) importance in identifying high risk plaques, which can contribute to increased rupture hazard. Methods: We selected 30 patients with stabile angina pectoris. 50 plaques were analyzed with coronary angiography digital assessment tool and IVUS similarly. Differences of stenoses measured by both methods, then were calculated and compared to composition of plaques evaluated by IVUS-VH. Results: Plaques were mostly formed of fibrous tissue (FI) (2.6 mm2; 57.89 %). Necrosis was found to make in average one-fifth of analyzed plaques (0.75 mm2, 19.60 %). Calcification made up the smallest part of plaques (0.3 mm2, 8.58 %). Plaques with higher necrosis component appeared to be significantly greater in IVUS compared to coronary angiography. In group A necrosis made up 1.40±1.05 mm2; group B – 0.87±0.52 mm2, and group C – 0.62 ±0.45 mm2 (p= 0.020). The same tendency was observed with FI: group A – 3.38±3.20 mm2; group B – 2.90±2.6 mm2 and group C – 2.04±165 mm2 (p= 0.082). Correlation analysis revealed negative moderate relationship between groups and necrosis percentage (r= –0.40, p= 0.004), and FI (r= –0.29, p= 0.039) components of the plaques. Conclusion: IVUS-VH provides new insight into the evaluation of different composition of plaques. However, despite the advantages, IVUS-VH remains costly and not always technically adaptive procedure, so it is necessary to pursue for new methods or technologies to identify atherosclerotic plaques at risk

Smart sensors for estimation of power interaction of an athlete with water surface when paddling in the cycle of rowing locomotions

Theoretical justification for the choice of the strain-resistant element location on the loom of the canoe paddle in order to register the power parameters of interaction of an athlete with the paddle in natural conditions of rowing locomotions is presented in the article. Taking into account the introduced simplifications, a classical task of calculating the materials resistance from which the loom of the paddle is manufactured is submitted. The obtained result is reliable and allows with sufficient degree of accuracy to determine mechanical stresses arising in the process of rowing in location of measuring devices – tensometers, which provides registration of objective indices characterizing power of forces applied by an athlete in the support (water) part of a stroke. Besides, based on the MEMS-sensors readings, mathematical calculation of forces applied to the paddle in the process of rowing was made, which in specified conditions allows to estimate regularities of values ratio of the recorded dynamic parameters

Design and the main parameters of tube-shaped ultrasound wave guide wire

Cardiovascular diseases are the leading cause of death among people up to 65 years old. One of the most common cardiovascular diseases is arterothrombosis. For recanalization of arteries usage of advanced invasive mechanical devices is required. The tube-shaped ultrasound waveguide wire was designed, investigated and validated by computational finite element method and experimental techniques