Comparison of Passive and Active Methods for Minimization of Sound Radiation by Vibrating Clamped Plate

The paper is an analytical and experimental study of a smart structure consisting of steel plate with bonded piezoelectric transducers and porous elastomer layer. Active control of sound radiation from a plate clamped at the edge square is examined. Simulations and numerical computation of the experiment are performed in Ansys environment. Calculations of plate vibration and sound radiation under stepped harmonic force are performed. The experimental setup consists of two rooms with the test opening in between. A variety of test cases were studied for three different configurations: steel plate + piezoelectric transducer, steel plate + elastomer layer, steel plate + piezoelectric transducer + elastomer layer. The aim of the paper is to illustrate the possibilities of using piezoelectric materials as an active control with elastomer layers as passive methods in one structure to improve the transmission loss

Active Vibration Control of Rectangular Plate with Distributed Piezoelements Excited Acoustically and Mechanically

The paper presents simulations and research results of testing of the aluminium plate with active vibration control. The aim of this paper is to analyze and compare two ways of excitation of the test plate, various influence on its vibrations and active damping control. Vibration control of the smart structure is realized through four piezoceramic PZT actuators and one PZT sensor bonded to the plate. Simulations and numerical computations of the structure are performed in ANSYS environment. Measurements are executed on specialized sound insulation suite for small elements in reverberation chamber. At the beginning white noise sound source is used in purpose to measure basic vibration modes. After numerical computations and measurements three particular frequencies has been chosen and for them active damping is applied. There are two ways of exciting the test plate; first method is sound wave, second is mechanical vibrations via one of piezoceramics. The test results indicate that PZTs can decrease vibrations by approximately 15 dB for a pure sound input with acoustic excitation method, for mechanical excitation method 18 dB for a sinus vibration signal is achieved

Porównanie aktywnych i biernych metod w redukcji promieniowania akustycznego utwierdzonej płyty

The paper is an analytical and experimental study of smart structure, which consist of steel plate with bonded PZTs and porous elastomer layer. Active control of sound radiation from a clamped at the edge square plate is examined. Simulations and numerical computation of the experiment are performed in ANSYS environment. Calculations of plate vibration and sound radiation under stepped harmonic force are performed. The experimental set-up is placed in coupled reverberation chambers and the test plate is placed in the hole. A variety o test cases were studied for three different plates: steel plate + PZT, steel plate + elastomer layer, steel plate + PZT + elastomer layer. The aim of the paper is to illustrate the possibilities of using piezoelectric materials as an active control and elastomer layers as passive methods in one structure to improve the transmission loss.Artykuł przedstawia badania analityczne i symulacje oraz pomiary eksperymentalne inteligentnej struktury składającej się z płyty stalowej z przyklejonymi elementami aktywnymi PZT i naniesioną na powierzchnię warstwą elastomerową. Zbadano aktywne sterowanie promieniowaniem akustycznym płyty utwierdzonej na brzegach. Obliczenia numeryczne symulacji wykonano w środowisku obliczeniowym ANSYS. Obliczone zostały drgania i promieniowanie akustyczne płyty pod wpływem wymuszenia harmonicznego przez jeden z elementów PZT. Stanowisko pomiarowe usytuowano w zespole komór sprzężonych. Na stanowisku przetestowano kilka rodzajów obiektów badań: płyta stalowa z elementami PZT, płyta stalowa z warstwą elastomerową, płyta stalowa z elementami PZT i warstwą elastomerową. Celem artykułu jest pokazanie możliwości wykorzystania w jednej strukturze materiałów piezoelektrycznych, jako metody aktywnej i warstwy elastomerowej, jako metody pasywnej do zwiększenia dzwiękoizolacyjności struktury

Metoda otrzymywania roślinnych baz olejowych o zróżnicowanej klasie lepkościowej

This publication aims at presenting a method for obtaining vegetable oil with different viscosity classes. The subject of the research focused the on oxidation of rapeseed oil and the determination of the proprieties of this reaction. The most advantageous results have been achieved when the process was held at a temperature of 150oC. Physical and chemical properties of the base oil and obtained oils with different viscosity classes have been determined.W artykule przedstawiono metodę otrzymania oleju roślinnego o różnych klasach lepkościowych. Przedmiotem badań była reakcja utleniania oleju rzepakowego oraz określenie warunków jej przebiegu. Najkorzystniejsze rezultaty uzyskano dla prowadzenia procesu utleniania w temperaturze 150oC. Oceniono właściwości fizykochemiczne oleju bazowego oraz uzyskanych olejów o różnych lepkościach

Variable Sound Insulation Structure with MFC Elements

Additional sound sources are used as actuators in the vast majority of active noise reduction systems. One of the possible opportunities to extend the field of applications of active noise reduction systems is using active structures of variable sound insulation. The paper presents an analysis of ways of reducing noise with a structure of variable sound insulation consisting of a metal plate, active elements (Macro Fiber Composite), and a control system. The paper presents results of acoustic radiation simulations and measurements of sound intensity generated by the structure under the influence of stimulation by an acoustic wave. Simulations of mechanical vibrations and acoustic radiation for the plate were performed with the finite element method and ANSYS software. Simulation results made it possible to select locations for gluing the active elements and sensors. Analyses of the sound pressure level in the space to which the plate is radiating made it possible to determine dominant frequencies in the characteristics and, as a result, indicate vibration modes that can be reduced. Sound intensity measurements were performed with a three-way probe of USP mini Microflown. Results of simulations and measurements show that it is possible to achieve an improvement of the insulating power of a metal plate by approx. 10 dB

Role of positron emission tomography and bone scintigraphy in the evaluation of bone involvement in metastatic pheochromocytoma and paraganglioma: specific implications for succinate dehydrogenase enzyme subunit B gene mutations.

Contains fulltext : 71093timmers.pdf (publisher's version ) (Closed access)We performed a retrospective analysis of 71 subjects with metastatic pheochromocytoma and paraganglioma (30 subjects with mutation of succinate dehydrogenase enzyme subunit B (SDHB) gene and 41 subjects without SDHB mutation). Sixty-nine percent presented with bone metastases (SDHB +/-: 77% vs 63%), 39% with liver metastases (SDHB +/-: 27% vs 47%), and 32% with lung metastases (SDHB +/-: 37% vs 29%). The most common sites of bone involvement were thoracic spine (80%; SDHB+/-: 83% vs 77%), lumbar spine (78%; SDHB +/-: 78% vs 75%), and pelvic and sacral bones (78%; SDHB +/-: 91% vs 65%, P=0.04). Subjects with SDHB mutation also showed significantly higher involvement of long bones (SDHB +/-: 78% vs 30%, P=0.007) than those without the mutation. The best overall sensitivity in detecting bone metastases demonstrated positron emission tomography (PET) with 6-[(18)F]-fluorodopamine ([(18)F]-FDA; 90%), followed by bone scintigraphy (82%), computed tomography or magnetic resonance imaging (CT/MRI; 78%), 2-[(18)F]-fluoro-2-deoxy-d-glucose ([(18)F]-FDG) PET (76%), and scintigraphy with [(123/131)I]-metaiodobenzylguanidine (71%). In subjects with SDHB mutation, imaging modalities with best sensitivities for detecting bone metastases were CT/MRI (96%), bone scintigraphy (95%), and [(18)F]-FDG PET (92%). In subjects without SDHB mutations, the modality with the best sensitivity for bone metastases was [(18)F]-FDA PET (100%). In conclusion, bone scintigraphy should be used in the staging of patients with malignant pheochromocytoma and paraganglioma, particularly in patients with SDHB mutations. As for PET imaging, [(18)F]-FDG PET is highly recommended in SDHB mutation patients, whereas [(18)F]-FDA PET is recommended in patients without the mutation