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Dyski do magazynowania wodoru

Foltynowicz Zenon

Energia i Recykling : gospodarka obiegu zamkniętego

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2023

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nr 10

PL

Europejski Urząd Patentowy (EPO) co roku honoruje inspirujących wynalazców za ich wybitny wkład w poprawę naszego codziennego życia nagrodą European Inventor Award w kilku kategoriach. W 2023 roku nagrodę w kategorii „badania” otrzymał francuski zespół naukowców z CNRS (Patricia de Rango, Daniel Fruchart, Albin Chaise, Michel Jehan i Natalia Skryabina) za opracowanie dysków do bezpiecznego i efektywnego sposobu magazynowania wodoru. Według wynalazców, dyski te zapewniają bezpieczne, zrównoważone i stabilne przechowywanie wodoru.

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Dynamics of thin disk settling in two layered fuid with density transition

Mrokowska Magdalena M.

Acta Geophysica

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2020

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Vol. 68, no. 4

1145--1160

EN

Settling of solid particles in a stratifed ambient fuid is a process widely encountered in geophysical fows. A set of experiments demonstrating the settling behaviour (the pattern of trajectory, variation of particle orientation, and settling velocity with depth) of thin disks descending through a nonlinear density transition was performed. The results showed complex hydrodynamic interactions between a particle and a liquid causing settling orientation instabilities and unsteady particle descent in low to moderate Reynolds number regime. Five phases of settling were observed: two phases with stable horizontal, one with stable vertical disk position, and two reorientation phases; moreover, two local minima of settling velocity were identifed. It was demonstrated that thresholds for local minima and the frst reorientation depend on the settling dynamics in an upper layer, stratifcation conditions, and disk geometry. The comparison of settling behaviour of thin disks varying in diameter revealed that settling dynamics is sensitive to particle geometry mainly in the upper part of density transition with a non-obvious result that the frst minimum velocity is smaller for a disk with a larger diameter than for a disk with a smaller diameter. The analysis of settling trajectory showed that two reorientations are accompanied with a horizontal drift, which may be important in the context of interactions between particles settling in a group.

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Assessment of postural stability in patients with lumbar spine chronic disc disease

Truszczyńska A., Dobrzyńska M., Trzaskoma Z., Drzał-Grabiec J., Tarnowski A.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 4

71--77

EN

Purpose: The pain, motor and sensory deficits are common symptoms of the lumbar disc disorder, and they can significantly affect human postural control. The aim of this study was to assess postural stability in patients with severe symptoms of lumbar spine disc disease qualifying them for surgical treatment and to compare them with a control group. Methods The study involved 103 subjects: 54 patients and 49 healthy subjects. Patient’s mean age was 46.4 ± 11.3 years, mean body height 172.2 ± 10.3 cm, mean body mass was 83.1 ± 18.9 kg and mean body mass index (BMI) was 27.9 ± 5.2 kg m-2. The mean time of their recent pain episode was 9.7 ± 8.5 month. Results: We found statistically significant differences between postural stability in patients with lumbar spine disc disease and the control group. The measurements taken with eyes closed, as compared with the clinical control group, revealed higher and statistically significant values of the mean amplitude of COP, mean amplitude of COP on sagittal plane, and maximal sway in sagittal plane parameters. The analysis of pressure value differences between the right and left lower limbs in both groups revealed statistical significance. In the study population the difference was significantly greater in comparison to the control group. The patients has significantly greater asymmetry of lower limb load. Conclusions: 1. Patients with lumbar spine discogenic pain had decreased postural control. 2. The patients had significant asymmetry in foot pressure, resultant from pain radiating to a lower limb.

4

Graph methods in kinematical analysis of multi-speed epicyclic gears

Drewniak J., Zawiślak S.

International Journal of Applied Mechanics and Engineering

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2012

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Vol. 17, no. 3

791-798

EN

Multi-speed epicyclic gears are used automatic gear boxes when they are equipped with a control system. The methods of analysis of these gears are discussed in the paper. Graph based methods can be used for modelling and kinematic analysis of gears. The methods are roughly described. They were applied for modelling and analysis of an exemplary gear box. Their advantages consist in simplicity, algorithmic approach and usefulness. A comparison of results obtained by means of the graph and Willis approaches is presented. The equivalence of results confirms, the correctness of theoretical modelling.

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Effect of stresses in a disc with variable thickness with Poisson's ratio subjected to pressure by concept of seths theory

Pankaj T.

International Journal of Applied Mechanics and Engineering

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2012

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Vol. 17, no. 4

1237-1252

EN

Elastic-plastic transitional stresses in an annular disc having variable thickness and variable Posson's ratio subjected to internal pressure is derived by using Seth's transition theory. It is seen that thickness and Posson's ratio variation influence significantly the stresses and pressure required for initial yielding. The thickness variation reduces the magnitude of the stresses and pressure needed for a fully plastic state. It seems that for a fully plastic state that circumferential stresses are maximum at the outer surface.

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Przegląd i analiza technik odzyskiwania danych

Krzysiak Z.

Biuletyn Wojskowej Akademii Technicznej

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2007

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Vol. 56, nr sp.1

423-432

PL

Praca przedstawia opis podstawowych programów do odzyskiwania danych oraz ich analizę porównawczą.

EN

The paper presents description of basic programs for data recovery and their comparative analysis.

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Study on the experiments of the relationship between the geometric dimensions of flexural vibration disk and its vibration characteristics

Yuan Y., Ma Y., Chen M., Wang D., Zhao B.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

255--258

EN

Purpose: The vibration characteristics of flexural vibration disk in ultrasonic honing system were studied systematically through experiments. Design/methodology/approach: The vibration of flexural vibration disk was tested using the acoustic system of ultrasonic honing. Findings: The results showed that the amplitude of vibration disk increases with the reducing of its thickness, when the disk was thin disk (the ratio between the thickness and radius was less than or equal to one fifths) the vibration of disk was flexural vibration, the good vibration effect could be obtained. The maximal amplitudę could reach 20.5μm,at the same time, the number of the wave crests and size could be obtained. There exist amplifying characteristics in the vibration of the disk. When the diameter of disk was not changed, the resonant frequency would decrease with the reducing of the thickness of disk. The resonance could be excited at different frequencies. The corresponding maximal amplitude value provides certain reference value for the dimensional design and application of flexural vibration disk. Research limitations/implications: From analysis, the ratio between diameter and thickness of flexural vibration disk has direct effect on amplitude. The rational diameter and thickness of flexural vibration disk should be selected according to specific machining conditions and the size requirements of the whole honing equipment during the course of design of ultrasonic honing acoustic system. Originality/value: The studied on relationship between geometric dimensions of flexural vibration disk and its vibration characteristics were made.

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The analysis of the natural frequencies of disc for the tyres in program COSMOS M

Vavro J., Kopecky M., Kostial P., Slabeycius J., Fandakova M., Hajska E., Skulec M.

Zeszyty Naukowe Politechniki Poznańskiej. Maszyny Robocze i Transport

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2002

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Nr 54

201-206

EN

The model of the tyre disk was created in software Autocad and COSMOS M. There are calculated the first ten eigen frequencies disk in this article with the help of the software COSMOSM.

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Flow of a second order/grade fluid due to non-coaxial rotation of a porous disc and the fluid at infinity

Ersoy H. V., Baris S.

International Journal of Applied Mechanics and Engineering

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2002

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Vol. 7, no 4

1189-1198

EN

The flow of an incompressible second order/grade fluid due to non-coaxial rotation of a porous disk and the fluid at infinity with the common angular velocity is studied. It is shown that there are physically acceptable solutions for both suction and blowing cases, depending on the sign of the material modulus 'alpha'1 . It is observed that the elasticity of the fluid causes the boundary layer thickness to increase in the case of suction, whereas it causes the boundary layer thickness to decrease in the case of blowing.