Wyniki wyszukiwania - BazTech

1

Field Experiment as a Tool to Verify The Effectiveness of Prototype Track Structure Components Aimed at Reducing Railway Noise Nuisance

Kraśkiewicz Cezary, Klekot Grzegorz, Książka Piotr, Zbiciak Artur, Mossakowski Przemysław, Chacińska Patrycja, Al Sabouni-Zawadzka Anna

Archives of Acoustics

|

2024

|

Vol. 49, nr 1

61--71

EN

The almost unlimited possibilities of modern computational tools create the temptation to study phenomena related to the operation of engineering objects exclusively using complex numerical simulations. However, the fascination with multi-parametric complex computational models, whose solutions are obtained using iterative techniques, may result in qualitative discrepancies between reality and virtual simulations. The need to verify on real objects the conclusions obtained from numerical calculations is therefore indisputable. The enormous cost and uniqueness of large-scale test stands significantly limit the possibility of conducting tests under real conditions. The solution may be an experiment focused on testing features relevant to the given task, while minimising the dimensions of the objects under consideration. Such conditions led to the concept of conducting a series of field experiments to verify the effectiveness of prototype track components, which were developed using numerical simulations to reduce the noise caused by passing trains. The main aim of this study is to examine the acoustic efficiency of prototype porous concrete sound absorbing panels, in relation to the ballasted and ballastless track structures. Presented results of the proposed unconventional experiments carried out on an improvised test stand using the recorded acoustic signals confirm the effectiveness of the developed vibroacoustic isolators.

2

Application of quantum entanglement induced polarization for dual-positron and prompt gamma imaging

Romanchek Gregory, Shoop Greyson, Abbaszadeh Shiva

Bio-Algorithms and Med-Systems

|

2023

|

Vol. 19, no. 1

9--16

EN

The intrinsic resolution of Positron Emission Tomography (PET) imaging is bound by positron range effects, wherein the radioactive decay of the imaging tracer occurs at a disjoint location from positron annihilation. Compounding this issue are the variable ranges positrons achieve, depending on tracer species (the energy they are emitted with) and the medium they travel in (bone vs soft tissue, for example) - causing the range to span more than an order of magnitude across various study scenarios (~0.19 mm to ~6.4 mm). Radioisotopes, such as Zr-89, exhibit dual emissions of positron and prompt gammas, offering an opportunity for accurate tracer positioning as prompt gammas originate from the tracer location. These multi-emission radiotracers have historically suffered from increased noise corresponding to the third gamma interfering in annihilation gamma coincidence pairing. Recent advancements, however, have brought to light the unique property of annihilation gammas having scattering kinematics distinct from random gamma pairs. These properties are born from the singular quantum entanglement state available to the gamma pair following para-positronium decay which prescribes linearly orthogonal polarization. Such coherent polarization is not shared by prompt gamma emissions, offering an opportunity for their discrimination. We present an investigation into this technique, comparing the distribution of relevant scattering kinematics of entangled annihilation gammas and corresponding prompt gammas via a Monte Carlo simulation.

3

Sprawdzenie przydatności metamateriału akustycznego do redukowania hałasu średnio- i wysokoczęstotliwościowego - symulacje numeryczne

Szczepański Grzegorz, Podleśna Marlena, Łada Krzysztof, Włudarczyk Anna

Bezpieczeństwo Pracy : nauka i praktyka

|

2023

|

nr 4

22-27

PL

Hałas na stanowiskach pracy wciąż jest głównym zagrożeniem dla pracowników zakładów przemysłowych. Zastosowanie obudów i barier dźwiękoizolacyjnych w celu ograniczania tego zagrożenia nie zawsze jest możliwe lub wystarczające. Stosunkowo nowym i obiecującym sposobem redukcji hałasu jest wykorzystanie metamateriałów akustycznych, które przekierowują bądź pochłaniają falę dźwiękową, a najwyższą skuteczność wykazują przy częstotliwości bliskiej częstotliwości rezonansowej. Metamateriały akustyczne służą przede wszystkim do redukcji hałasu wąskopasmowego. W artykule przedstawiono ich modele numeryczne, które posłużyły do wyznaczenia częstotliwości rezonansowych. Symulacje przeprowadzono w dwóch różnych programach przeznaczonych do analizy metodą elementów skończonych (MES). Otrzymane wyniki wskazują, że metamateriał o strukturze tunelowej z umieszczonymi wewnątrz rezonatorami Helmholtza może redukować hałas w kilku pasmach częstotliwości (w zakresie średnio- i wysokoczęstotliwościowym) oraz w większym stopniu niż metamateriał o strukturze tunelowej bez rezonatorów.

EN

Noise in workplace environments is still the main risk factor for workers in industrial plants. The use of sound insulation enclosures and soundproof barriers to reduce this risk is not always possible or sufficient. A relatively new solution used to reduce noise are acoustic metamaterials that redirect or absorb the sound wave, and show the highest efficiency at frequencies close to the resonant frequency. They are primarily used for narrowband noise. The article presents the developed numerical models which were used to determine the resonant frequencies. Simulations were performed in two different programs based on finite element method (FEM). The obtained results indicate that the tunnel structure with Helmholtz resonators placed within can suppress the noise in several frequency bands (mid-frequency and high-frequency range) and to a greater extent than tunnel structures without resonators.

4

Modernization of the ZEUS TECHNO RT-20C ring nail mill

Podsiadło Halina, Bąbik Andrzej

Mechanik

|

2022

|

R. 95, nr 8-9

56--61

EN

The article presents the modernization of the ZEUS TECHNO RT-20C ring nail mill, thanks to which harmful noise has been reduced.

PL

W artykule przedstawiono sposób modernizacji walcarki do gwoździ pierścieniowych ZEUS TECHNO RT-20C, dzięki któremu został obniżony szkodliwy hałas.

5

Experimental and numerical investigation on the noise development in fluid power units: an overview

Fiebig Wiesław, Wróbel Jakub

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 4

art. no. e166, 2022

EN

Low noise fluid power units become a rapidly increasing demand in modern industry. This paper describes the generation of vibrations and noise in fluid power units, which in many industrial applications have a decisive influence on the increased noise emission. The causes of vibrations and noise in displacement pumps were first described which are loaded with very high dynamic forces originating from variable pressures. For this reason, positive displacement pumps are often considered the main sources of noise in fluid power units. The location of noise sources shows that often other fluid power unit elements having a larger surface area, such as the electric motor and the tank, can be decisive in the generation of noise. A system-based approach is considered, whereby the entire structure of the fluid power unit, including the fluid. In particular, the FE model of the fluid power unit was developed to calculate the system's natural frequencies, which has been validated using experimental modal analyses. Based on the FEA results, the sensitivity analysis enables the determination of changes leading to the reduction of vibrations and noise. The presented approach can be extended to other configurations of system components and contributes to the development of quieter fluid power units.

6

EKO-budynki wymagają EKO-elewacji

Kram Dorota

Materiały Budowlane

|

2021

|

nr 9

28--31

PL

Zwiększająca się świadomość inżynierów budownictwa i użytkowników obiektów budowlanych, dotycząca nieodwracalnych skutków globalnego ocieplenia, skłania nas do myślenia, jakie kierunki działania należy podejmować, kształtując zewnętrzną skorupę budynku, a wraz z nią elewację będącą jego wizytówką. Artykuł pokazuje newralgiczne punkty, jakie powinniśmy brać pod uwagę, kształtując elewację budynku ekologicznego.

EN

The constantly growing awareness of civil engineers and users of building facilities as to the irreversible effects of global warming, prompts us to think what directions we should take when shaping the outer shell of a building and with it the façade, which is this showcase. The article shows the critical points that should be taken into account when shaping the facade of an ecological building.

7

Krótki przegląd technologii testowania układów scalonych na płytkach krzemowych

Dąbrowiecki Krzysztof

Elektronika : konstrukcje, technologie, zastosowania

|

2021

|

Vol. 62, nr 1

15--18

PL

W artykule przedstawiono testy weryfikujące w fazie budowy i montażu modułów elektronicznych. Omówiono urządzenia i główne technologie przeznaczone do testowania płytek krzemowych z układami scalonymi. Na przykładzie rezystancji styku zilustrowano złożoność powiązań parametrów mających wpływ na dobry kontakt pomiędzy końcówkami mikrokontaktorów i punktami testowymi układów scalonych

EN

The article presents the verification tests during the construction and assembly phase of electronic components. The devices and main technologies for testing of silicon wafers are discussed. The example of the contact resistance illustrates the complexity of the parameters relationship influencing a good contact between the probe tips and the test points of the integrated circuits

8

Rotorcraft thickness noise control

Szulc O.

Archives of Mechanics

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2021

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Vol. 73, nr 4

391--417

EN

The paper describes an innovative idea of Thickness Noise Control (TNC) based on adoption of a flow control strategy (i.e. surface ventilation) for acoustic attenuation of helicopter rotor periodic noise. The TNC method is relying on incorporation of multiple cavities (closed by perforated panels and linked to low- and high-pressure reservoirs) located in a symmetrical manner at front and rear portions of the blade tip. The efficiency of the new approach is verified using a two-bladed model rotor of Purcell (untwisted variant of the blade of Bell UH-1H Iroquois helicopter) in low-thrust hover conditions. The results of numerical simulations, obtained with CFD solver (Spalart–Allmaras turbulence and Bohning–Doerffer transpiration models), indicate that in the near-field of the blade tip, both the amplitude and spectral contents of pressure impulses of emitted thickness noise are significantly improved. The TNC method, in the proposed unsteady mode of operation, turns out to be a suitable means of thickness noise reduction in forward flight. Moreover, it is demonstrated that by proper azimuthal activation the efficiency is almost unaltered, while the rotor torque penalty and required transpiration mass-flux are decreased by a factor of 3–5 compared to a steady arrangement.

9

Active system for reduction of noise parameters of car muffler with the use of pressure sensors based on silicon microcrystals

Zinko R.V., Kutrakov A.P., Shybanov S.V., Zashchepkina N.M., Markina O.M.

Archives of Materials Science and Engineering

|

2021

|

Vol. 109, nr 1

35--41

EN

Purpose: The article contains the results of research and development of a system for active noise damping of an automobile engine. The proposed system of active noise suppression can significantly reduce the sound pressure level in the frequency band up to 500 Hz. The robotic principle of the developed system is based on the addition of an additional buffer tank with a variable volume in the silencer system. The use of high-temperature sensors with strain gauges based on silicon microcrystals to obtain information on the parameters of sound vibrations arising during the exhaust gas outflow made it possible to create a control system for changing the volume of the buffer tank. The results of testing the proposed system of active noise suppression of an internal combustion engine are presented. Design/methodology/approach: The active noise suppression system based on the Helmholtz resonator used tools to control general noise levels, experimental tests, complex mathematical modelling of acoustic processes in Solidworks, taking into account the conditions of propagation and attenuation of sound energy by intermediate closed volumes. Findings: The use of an additional resonator chamber with variable volume in the exhaust muffler of the internal combustion engine allowed to reduce the resonant phenomena in the zone of low-frequency pulsations of exhaust gas pressure from 57 Hz to 43 Hz at frequency drift in the range of 310… 350 Hz, which significantly improved its noise characteristics. Research limitations/implications: For further research, to improve the characteristics of the active noise suppression system, it is advisable to consider the use of several in in transient modes of engine operation. Practical implications: The developed design of active noise reduction is simpler in comparison with analogs and allows reducing the noise of exhaust gases in a low-frequency range. Originality/value: To reduce the noise, a variable-volume Helmholtz resonator was used, the efficiency of which is provided by high-temperature sensors of the original design.

10

Sound Field Modelling and Noise Reduction for a Forklift Power Compartment Based on Perfectly Matched Layer and Acoustic Packaging Design

Zhang Enlai, Liu Zhiqi, Zhang Jingjing, Lin Jiahe

Archives of Acoustics

|

2021

|

Vol. 46, No. 3

491--498

EN

The core goal of this paper is to put forward a feasible scheme of noise reduction for a target forklift on the basis of solving the problem of vibration and acoustic radiation from complex structures in infinite domain. Based on the previous report and vibration acceleration tests, the acoustic virtual wind tunnel model of forklift power compartment was established using finite element method and boundary element method, in which the perfectly matched layer was first applied to simulate the attenuation propagation of sound waves in air. In addition, according to the distribution characteristics of sound pressure field with different frequencies, the acoustic energy mainly radiated through the bottom and right side, and concentrated in the low frequency. Consequently, the acoustic packaging design for the whole forklift power compartment was presented, and a satisfying noise reduction effect was achieved.

11

Nonlinear Nonlocal Algorithm for Video Filtering

El Ouafdi Ahmed Fouad, El Houari Hassan

Advances in Science and Technology. Research Journal

|

2021

|

Vol. 15, no 4

243--252

EN

Video sequences are frequently contaminated by noise throughout the acquisition process, resulting in considerable degradation of video display quality. In this paper, we present a novel method of video filtering. The proposed filter is developed from an optimization problem in which a Bayesian term and a noisy video sequence prior distribution are combined. The method begins by segmenting the video sequence into space-time blocks and then substituting each noisy block by a weighted average of non-local neighbor blocks. Gradient-based weights are used to dynamically adjust the edge preservation and smoothness of the reference block. The obtained formulation enables nonlinear filtering and, hence, preserving key features such as edges and corners while using the intrinsic Bayesian filtering framework. Experiments on different video sequences with varying degrees of noise show that the proposed method performs better than state-of-the-art video filtering approaches.

12

Sposoby redukcji hałasu bezpilotowych statków powietrznych

Tatko Sebastian, Chruściel Eryk, Konatowski Stanisław

Elektronika : konstrukcje, technologie, zastosowania

|

2020

|

Vol. 61, nr 11

13--20

PL

W artykule scharakteryzowane zostały metody pozwalające na redukcję hałasu wytwarzanego przez bezpilotowe statki powietrzne (BSP). Dokonano oceny ich skuteczności w oparciu o dostępne wyniki symulacji oraz własne pomiary.

EN

This article describes methods that can be used to reduce unwanted noise created by UAV’s. Effectiveness of these methods has been assessed based on available simulation results as well as own measurements.

13

Use of Acoustic Camera for Noise Sources Localization and Noise Reduction in the Industrial Plant

Fiebig Wiesław, Dąbrowski Damian

Archives of Acoustics

|

2020

|

Vol. 45, No. 1

111--117

EN

The paper presents results of the localization of main noise sources in the industrial plant. Identification of main noise sources was made with an acoustic camera using Beamforming Method. Parallel to the measurements by means of the acoustic camera, sound level measurements on the main noise sources have been performed. Based on the calculations, prediction regarding the noise emission at residential buildings located near to the plant has been determined. Acoustic noise maps have been performed with LEQ Professional software, which includes the 3D geometry of the buildings inside the plant. It has been established that, after introduction of noise reduction measures in the plant, the noise levels at the observation points in the residential area meets the limit values.

14

Attenuation Characteristics of Vibration in a Locally Resonant Phononic Crystal Frame Structure

Wang Yukun, Qian Denghui, Wu Jinghong, He Feiyang

Archives of Acoustics

|

2020

|

Vol. 45, No. 3

557--562

EN

In this paper, a frame structure based on the locally resonant (LR) mechanism of phononic crystals (PCs) is designed on account of the wide application of frame structures in high-rise buildings, and the band structures, displacement fields of eigenmodes, and transmission power spectrums of corresponding finite structure are calculated by finite element (FE) method. Numerical results and further analysis demonstrate that a full band gap with low starting frequency can be opened by the frame structure formed by periodically combining soft and hard materials, and the starting frequency can be further lowered with the adjustment of corresponding geometric parameters, which provides a theoretical basis for the studies on vibration insulation and noise reduction of high-rise buildings.

15

Zmiana charakterystyki dynamicznej toru w celu ograniczenia emisji hałasu – badania numeryczne

Brzeziński Karol, Michalczyk Rafał

Przegląd Komunikacyjny

|

2019

|

R. 74, nr 5

2--9

PL

Artykuł przedstawia koncepcję i wstępne wyniki badań numerycznych zmiany charakterystyki dynamicznej toru w celu ograniczenia emisji hałasu. Objaśniono związek teoretyczny między badaną charakterystyką dynamiczną toru (TDR – Track Decay Rate) a hałasem, a następnie opisano metodykę budowy modelu MES, w którym prowadzono symulację badania normowego. Przeanalizowano symulację zastosowania czterech wariantów dociążenia, na torach z szynami o profi lu 49E1 oraz 60E1. Symulacje pozwoliły przeanalizować w jaki sposób zwiększenie masy toku szynowego wpływają na charakterystykę dynamiczną toru, a tym samym na emisję hałasu. Okazuje się, że uzyskany efekt może powodować zmniejszenie emisji hałasu w niektórych częstotliwościach, a zwiększenie w innych.

EN

The paper presents the concept and preliminary results of numerical study of changes in the rail track dynamic characteristics. Change of the characteristics is introduced in order to reduce noise emissions. The theoretical relationship between the studied track dynamic characteristics (TDR - Track Decay Rate) and noise was briefly explained, and then the methodology of FEM modelling for the standard test simulation was described. Four mass modifi cation variants and two rail types (49E1 and 60E1 profiles) were analyzed. Numerical study show correlation between the railroad track mass increase and its dynamic characteristics and thus the noise emission. It turns out that the obtained effect may cause reduction of noise emission in some frequencies, and increase in others.

16

Emisja akustyczna z hutniczych urządzeń cieplnych – wpływ parametrów eksploatacyjnych

Rozpondek Maciej

Hutnik, Wiadomości Hutnicze

|

2019

|

Vol. 86, nr 9

291--297

PL

Scharakteryzowano emisję hałasu z hutniczych urządzeń cieplnych. Przeanalizowano wyniki badań hałasu wentylatora powietrza bez i z zainstalowaną obudową dźwiękochłonną. Porównano wyniki badań widm hałasu palnika spalającego paliwo ciekłe – olej lekki z danymi literaturowymi palnika spalającego butan. Przedstawiono możliwości wykorzystania charakterystyk akustycznych wentylatorów i widm hałasu z procesów spalania do szybkiej, bezinwazyjnej diagnostyki eksploatacyjnej hutniczych urządzeń cieplnych.

EN

Noise emission from metallurgical thermal devices has been characterized. The results of the noise analysis of the air fan were analyzed without and with sound absorbing housing installed. The results of the noise spectra of the liquid fuel burner - light oil were compared with the literature data of the butane burner. The possibilities of using acoustic characteristics of ventilators and octave spectras of noise from combustion processes for fast, noninvasive operational diagnostics of metallurgical thermal equipment’s were presented.

17

Development of non-contact fatigue crack propagation monitoring method using air-coupled acoustic emission system

Matsuo Takuma, Hatanaka Daisuke

Engineering Transactions

|

2019

|

Vol. 67, iss. 2

185--198

EN

A monitoring system for fatigue crack propagation was developed using a non-contact acoustic emission (AE) monitoring system. The AE signals generated during the plane bending fatigue test were first monitored. The AE generation rate increased after approximately 0.5 of the fatigue life ratio. The maximum amplitude of the AE signals increased with a tendency similar to that of the crack propagation. The sensor sensitivities for the flat and arced surfaces were then compared. The sensitivity improved when the specimen surface was flat. The bar specimen with plane surfaces was used for the AE monitoring of the rotary bending fatigue test. From 0.715 of the fatigue life ratio, the AE generation rate increased after crack generation. The AE signals were detected at an earlier stage of the fatigue life in the flat surface specimen compared with the arc surface specimen during the rotary bending fatigue test. The detection of fatigue cracks in the rotary component at an early stage was possible using a non-contact AE monitoring system.

18

Improved robust weighted averaging for event-related potentials in EEG

Kotowski Krzysztof, Stapor Katarzyna, Leski Jacek

Biocybernetics and Biomedical Engineering

|

2019

|

Vol. 39, no. 4

1036--1046

EN

The aim of this study was to improve the robust weighted averaging based on criterion function minimization and assess its effectiveness for extracting event-related brain potentials (ERP) from electroencephalographic (EEG) recordings. The areas of improvement include significantly lower averaging error (45% lower RMSE and 37% lower maximum difference than for original implementation) and increased robustness to local minima, strong outliers and corrupted epochs common to real-life EEG signals, especially from low-cost devices. Our proposed procedure was tested on two datasets, one artificially generated for purposes of this study (including different noise sources) and one real-life dataset collected with Emotiv EPOCþ. The lower error results mainly from more effective rejection (lowering the weights) of corrupted epochs by integrating the correlation-based weighting. The advantages of our method over pure correlation-based weighting are lower RMSE (up to two times) and robustness to the algorithm initialization and strong outliers. The performance of the methods was measured using bootstrap testing to avoid dependency of results on data. It shows that our improvements lead to significantly lower error, especially when the EEG signal is not filtered. The values of the parameters were adjusted for EEG signals but they can easily be incorporated in other repetitive electrophysiological measurement techniques.

19

Tłumiki torowe i przyszynowe jako innowacyjne rozwiązania dla ochrony ludzi i środowiska przed hałasem od ruchu kolejowego

Brzeziński K., Kraśkiewicz C., Oleksiewicz W., Płudowska-Zagrajek M., Wasilewski K.

Zeszyty Naukowo-Techniczne Stowarzyszenia Inżynierów i Techników Komunikacji w Krakowie. Seria: Materiały Konferencyjne

|

2018

|

Nr 1(115)

33--46

PL

Wzrost prędkości pojazdów szynowych, poza skróceniem czasów przejazdu, powoduje również m.in.: zwiększoną emisję hałasu, który negatywnie oddziałuje na ludzi i środowisko. Aby zminimalizować ten negatywny efekt, stosuje się różnorodne metody ograniczające poziom emisji hałasu do otoczenia, jednak nie zawsze tradycyjne metody przynoszą zadowalające efekty lub są możliwe do zastosowania. Zwiększenie skuteczności tych metod można osiągnąć przez dodatkowe, innowacyjne rozwiązania określane mianem tłumików przyszynowych i tłumików torowych, będące przedmiotem grantu badawczego „Innowacyjne rozwiązania w zakresie ochrony ludzi i środowiska przed hałasem od ruchu kolejowego – InRaNoS”.

EN

The increase in the speed of rail vehicles causes an increased noise emission, what may have a negative effect on people and environment. To minimize this negative impact, various methods are used to reduce noise emission to the environment. However, not always traditional methods bring satisfactory results or are possible to apply. The alternative to them are innovative solutions, such as dampers of the rails and track suppressors, being the subject of the research grant “Innovative solutions of people and the environment protection against rail traffic noise - InRaNoS”

20

Konstrukcja elektrometru wibracyjnego z identyfikacją znaku ładunku

Pomianowski J., Szoka W.

Przegląd Elektrotechniczny

|

2018

|

R. 94, nr 7

150--153

PL

Artykuł przedstawia nietypowe rozwiązanie elektrometru wibracyjnego z detekcją synchroniczną służącego do pomiaru napięć statycznych w zakresie od 2,5 V do 10 kV lub pól elektrycznych o natężeniu od 120V/m. Rezystancja wejściowa przyrządu jest ograniczona jedynie upływnością izolacji elektrody wejściowej. Skonstruowany elektrometr umożliwia identyfikację znaku ładunku elektrycznego bez skomplikowanych układów fotoelektrycznych śledzących fazę ruchu elektrody drgającej. Funkcji określania znaku często nie posiadają nawet elektrometry laboratoryjne, np. elektrometr z młynkiem polowym typu MFM 200A. Przyrząd jest odporny na zakłócenia o częstotliwości 50 Hz oraz wyższej, więc może być stosowany w warunkach przemysłowych. Miernik ma autonomiczne zasilanie z baterii 6 lub 9V.

EN

This paper presents an unusual solution of a vibrating electrometer with synchronous detection for measuring static voltages in the range from 2.5 V to 10 kV or electric fields having intensity from 120 V/m. The input resistance of the instrument is limited only by the leakage of the input electrode. The electrometer constructed by the author also allows identification of the electrical charge sign (a synchronous detector to reduce noise and recover the field sign (positive or negative) without complicated photovoltaic systems that track the phase of the vibrating electrode, e.g. electrometer with field mill type MFM 200A. The instrument is resistant to interference of 50 Hz or higher, so it can be used in industrial conditions. The meter has autonomous power from 6 or 9 V batteries.