Modern concepts of non-invasive methods for measuring intracranial pressure

The article presents the review of Russian and foreign literature, with the aim to summarize the results of the researches for the purpose of identification of the most perspective modern techniques of non‑invasive measurement of intracranial pressure. The methods of assessment of intracranial pressure based on morphological and functional features of intracranial organs are described: transcranial Doppler imaging, evaluation of tympanic membrane displacement, evaluation of blood pressure in retinal veins, evaluation of optic nerve diameter, CT imaging and magnetic resonance tomography. The attention is paid to merits and demerits of the presented methods, a possibility of their use in clinical practice.

Static characteristics of a hydrostatic thrust bearing with a membrane displacement compensator

The article discusses the design and also presents a mathematical model and method for calculation of static characteristics of a hydrostatic thrust bearing with a membrane-type displacement compensator. Formulae for calculation of compliance and load characteristics of the bearing are also presented, as well as deformation and compliance of the membrane at which zero compliance of the bearing is guaranteed.

Microfluidic Viscometer Using a Suspending Micromembrane for Measurement of Biosamples

The viscosity of biofluids such as blood and saliva can reflect an individual’s health conditions, and viscosity measurements are therefore considered in health monitoring and disease diagnosis. However, conventional viscometers can only handle a larger liquid volume beyond the quantity that can be extracted from a person. Though very effective, micro-sensors based on electrokinetic, ultrasonic, or other principles often have strict requirements for the supporting equipment and complicated procedures and signal processing. Sample contamination is always an important issue. In this paper, we report a microfluidic viscometer requiring a small volume of biosamples (<50 µL) and straightforward operation procedures. It is fabricated with low-cost and biocompatible polymeric materials as one-time-use devices, such that contamination is no longer the concern. It contains a suspending micromembrane located along a microchannel. Under a steady driving pressure, the membrane displacement is a function of viscosity of the liquid sample being tested. We derived a simple analytical relation and perform a simulation for converting the membrane displacement to the sample viscosity. We conducted experiments with liquids (water and mineral oil) with defined properties to verify such a relation. We further applied the micro-viscometer to measure bovine blood samples with different hematocrit levels. It can be concluded that the microfluidic viscometer has a high compatibility with a broad range of biomedical applications.

Construction and tests of the research stand with built-in correctors for the detection of gas outflow from long pipelines

The localization and identification of small gas leaks from a damaged gas pipeline is a very important but at the same time problematic and difficult process to carry out. Quick identification, estimation and precise localization of the leak leads to minimizing the financial and equipment losses resulting from damage. The most commonly used continuous internal methods of leak identification are based on pressure and mass intensity measurements flow at various places in the pipeline. The article presents a description of the construction of a test stand characterized by the correctors built in it and the examples of the signals obtained from its tests for different values of simulated leaks. The results obtained will be used to develop a new method for identifying and locating leakages from long pipelines. This method is based on the cross power spectral density of measured pipeline standard signals (pressure and mass flow) and the membrane displacement signals delivered from the test equipment (correctors) connected to the system.

Optical distortion compensation in the visual measurement with the new Depth From Defocus method

The paper presents new approach to compensation the inaccuracy of shape mapping of the flaccid membrane used in the extracorporeal pneumatic heart assist pump. The original shape of the membrane was determined using specially developed DFD type method. The major problems affecting the inaccuracy of mapping the membrane result from the phenomenon of optical distortion. The invented approach to compensate for optical distortion in the process of visual measurement as well as the results obtained were presented. Full Text: PDF ReferencesK. Murawski, Method of measuring the distance using one camera, Patent Application No P.408076 (2014) - in Polish. DirectLink K. Murawski, M. Murawska, T. Pustelny, The system and method of determining the shape of the membrane pneumatic pump of extracorporeal heart assist device, Patent Application No P.414104 (2015) - in Polish. DirectLink M. Gawlikowski, T. Pustelny, R. Kustosz, "The physical parameters estimation of physiologically worked heart prosthesis", Journal de Physique IV France 137, 73 (2006). CrossRef K. Murawski, "Measurement of Membrane Displacement Using a Motionless Camera", Acta Phys. Pol. A 128(1), 10 (2015). CrossRef K. Murawski, "Measurement of Membrane Displacement with a Motionless Camera Equipped with a Fixed Focus Lens", Metrology and Measurement Systems 22(1), 69 (2015). CrossRef K. Murawski, A. Arciuch, T. Pustelny, "Study of distance range visual measurement in the new Depth From Defocus method", Phot. Lett. Poland 8, 2 (2016). CrossRef L. Grad, K. Murawski, W. Sulej, "Research to improve the accuracy of determining the stroke volume of an artificial ventricle using the wavelet transform", Proc. SPIE 10455, 1045509 (2017). CrossRef W. Sulej, K. Murawski, "The membrane shape mapping of the artificial ventricle in the actual dimensions", Proc. FedCSIS ACSIS 11, 675 (2017). CrossRef W. Sulej, L. Grad, K. Murawski, "The technique of accuracy measurement of membrane shape mapping of an artificial ventricle", Proc. SPIE 10455, 104550B (2017). CrossRef