BazTech - Yadda

1

Mineralna izolacja natryskowa jako materiał poprawiający akustykę wnętrz

Marchacz Michał, Nowoświat Artur

Materiały Budowlane

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2022

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nr 8

14--16

PL

W artykule przedstawiono parametry akustyczne pianki natryskowej. Wyniki badań współczynnika pochłaniania dźwięku w komorze pogłosowej wskazują, że ma ona dobre właściwości dźwiękochłonne. Wyniki zweryfikowano przez zastosowanie materiału w pomieszczeniu o przeznaczeniu sakralnym w kształcie kopuły i o kubaturze 14 850 m3. Po zastosowaniu materiału czas pogłosu uległ znacznemu obniżeniu, co poprawiło warunki pogłosowe w pomieszczeniu.

EN

The article presents the acoustic parameters of the foam spray. The results of sound absorption coefficient obtained in the reverberation chamber show that the material has good soundproofing properties. Results were verified by applying the material in a dome-shaped sacral room with a cubature of 14 850 m3. Thanks to the use of the material, the reverberation time was significantly reduced. It has improved the reverberation conditions in the room.

2

The use of Vacuum Packed Particles with adaptable properties in acoustic applications

Zalewski R., Rutkowski M.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 2

403--416

EN

The aim of this paper is to present possibilities of using a new type of granular media in acoustics as innovative sound absorbers. Most materials of this type have a porous or fibrous structure. It is constant, and once manufactured, does not easily change its configuration. The examined material – Vacuum Packed Particles (VPP) is of a changeable structure. It can be assumed that the acoustical absorption of such structures can be modified and partially adjusted by an external factor. First steps in an experimental approach have been made – the acquired results are optimistic. Additional tests are being planned to confirm the observed phenomenon and to apply VPP as novel materials in acoustics. Basing on the preliminary experimental tests, it can be concluded that the considered structures could become a significant part of a multilayered structure which would have controllable sound absorption properties.

3

Light absorption properties of ‘Petrobaltic’ oil-in-water emulsion present in seawater

Baszanowska E., Otremba Z.

Journal of KONES

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2018

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Vol. 25, No. 3

59--64

EN

In the article, the characteristic of crude oil ‘Petrobaltic’ potentially present in the Baltic Sea water masses is considered in relation to the protection of marine environment. The main spectroscopic method to characterize various oils (crudes and refinery products like fuels and lubricating oils) is fluorescence. However, the absorbance measurements of oils are necessary due to the partial overlapping the spectra of natural seawater components and oil substances. Therefore, properties of crude oil are considered to expand the basis of spectroscopic properties of oils – typical marine organic pollutants – based on absorption measurements. Oils potentially found in the marine environment are, in addition to surface forms, also in-depth ones as oil-in-water emulsion. Therefore, in the article crude oil as oil-in-water emulsion form is considered. As a solvent demineralised water with salinity, corresponding to Baltic Sea salinity was used. Several concentrations of dispersed crude oil were prepared. The absorbance spectra in the UV and visual range of the light in the range from 240 to 600 nm, for each prepared samples are discussed. Based on the Lambert-Beer law for each wavelength of excitation, in the range 240-600 nm, the specific parameter absorption coefficient was determined. Obtained results indicate the rapid decreasing of the absorbance for this kind of oil in the wavelength range from 240 nm to 420 nm. However, in the shape of absorbance spectra is observed the characteristic wide and flat peak located at 260 nm for excitation wavelength, which could be a specific point for this kind of oil.

4

A Rough Estimation of Acoustics of the Cuboidal Room with Impedance Walls

Kocan-Krawczyk A., Brański A.

Archives of Acoustics

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2018

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Vol. 43, No. 2

227--233

EN

The cuboidal room acoustics field is modelled with the Fourier method. A combination of uniform, impedance boundary conditions imposed on walls is assumed, and they are expressed by absorption coefficient values. The absorption coefficient, in the full range of its values in the discrete form, is considered. With above assumptions, the formula for a rough estimation of the cuboidal room acoustics is derived. This approximate formula expresses the mean sound pressure level as a function of the absorption coefficient, frequency, and volume of the room separately. It is derived based on the least-squares approximation theory and it is a novelty in the cuboidal room acoustics. Theoretical considerations are illustrated via numerical calculations performed for the 3D acoustic problem. Quantitative results received with the help of the approximate formula may be a point of reference to the numerical calculations.

5

Determination of different optical properties for cubic titanium dioxide: an AB-INITIO approach

Dash Debashish, Pandey Chandan K., Chaudhury Saurabh, Tripathy Susanta K.

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 3

223--232

EN

This paper presents an analysis of optical properties of cubic titanium dioxide (TiO2) using Orthogonalized Linear Combinations of Atomic Orbitals (OLCAO) basis set under the framework of Density Functional Theory (DFT). Many optical properties such as refractive index, extinction coefficient, reflectivity, absorption coefficient, photoconductivity, and loss coefficient have been studied and analyzed thoroughly. From the analysis of optical properties, it is seen that, cubic TiO2 supports interband transition between states. Reflectivity of pyrite structure TiO2 lies within IRvisible – UV region due to which it qualifies for coating industry. Furthermore, the results are compared with previous theoretical as well as with experimental results. It is found that DFT based simulation produces results which are close approximation to experimental results.

6

Calculation of the ultimate efficiency of p-n-junction solar cells taking into account the semiconductor absorption coefficient

Tivanov M., Moskalev A., Kaputskaya I., Żukowski P.

Przegląd Elektrotechniczny

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2016

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R. 92, nr 8

85--87

EN

A model based on the famous model of Shockley–Queisser for calculation the ultimate efficiency of solar cells has been proposed, taking into account the dependence of the semiconductor absorption coefficient on the band-gap and on the energy of the incident photons. The dependence of the ultimate efficiency of solar cells on thickness of the absorption layer was found out for homogeneous solar cells.

PL

Opierając się na znanym modelu Shockley`a–Queisser`a do obliczeń maksymalnej sprawności ogniw słonecznych, zaproponowano model biorąc pod uwagę zależność współczynnika absorpcji półprzewodników od pasma wzbronionego oraz energii padających fotonów. Określono zależność maksymalnej sprawności ogniw słonecznych od grubości warstwy absorpcyjnej dla jednorodnych ogniw słonecznych.

7

Light absorption spectra for lubricate oil quality tracking in the combustion engine

Baszanowska E., Otremba Z.

Journal of KONES

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2016

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Vol. 23, No. 1

55--60

EN

The important role in the proper functioning of combustion engines plays the quality of lubricates oil. However, the quality of oil changes with the time of exploitation. Therefore, several parameters for examination of oil quality were determined; however, the indicator for quick and efficient tracking of evolution of oil with exploitation time is still searched. Taking into account the complex composition of oils, the ability of oils components to absorb light in various wavelengths is considered. In the article absorption properties of oils is discussed in relation to the time of circulation of oil in the engine lubricate system. For this study, two lubricate oils designated to lubricate the cylinder of vessel engines with different brightness and transparency were used. Oil samples were dissolved in organic solvent –n-hexane and several oil concentration were prepared based on dilution method. Absorbance spectra for eachsamples of oil were registered in the range of wavelength 240-600 nm. Obtained results indicate the changes of value of absorbance in relation to the kind of oil; however, the shape of absorbance spectra is independent from the kind of oil. For studied kinds of oil, characteristic peak independent from the kind of oil located at 260 nm was determined. Based on Lambert-Beer law absorption coefficient was identified as a potential indicator to oil quality evaluation with the time of exploitation in the engine system. Preliminary test for two fresh lubricate oils allow to conclude that absorption coefficient for selected wavelength located at 260 nm could be a sensitive parameter for quick estimating the degree of deterioration of the oil in engine system.

8

Absorption coefficient along a propagated ultra-short laser pulse in the air based on Kramers–Kronig relations

Malekshahi M, Naghavi K

Optica Applicata

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2015

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Vol. 45, nr 4

501--512

EN

In this manuscript, some effects such as nonlinear Kerr, stimulated Raman, and plasma generation effects lead to obtaining the nonlinear refraction index of the air along an intense ultra-short laser pulse based on one-dimensional propagation analysis. The variations in the pulse frequency by the self-phase modulation effect are investigated for achieving the functionality of the refractive index to the frequency. The mentioned functionality allows implementing Kramers–Kronig relations to measure the absorption coefficient. Results indicate that the front of the laser pulse faces a high rate of the energy loss whereas the back of the pulse experiences a gain. The implementation of Kramers–Kronig relations for a theoretical calculation of absorption coefficient variation along a laser pulse propagating in the air in which we have simultaneously taken into account the three above-mentioned effects distinguishes our work from other studies.

9

Utilizing Hollow-Structured Bamboo as Natural Sound Absorber

Putra A., Khair F. A., Nor M. J. M.

Archives of Acoustics

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2015

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Vol. 40, No. 4

601--608

EN

Studies to find alternative low environmental-impact materials for acoustic absorbers are still progressing, particularly those originated from natural materials. However, most of the established works are mainly focused on the fibrous-type absorbers. Discussion on the non-fibrous-type absorbers is still lacking and this therefore becomes the objective of this paper. Use of bamboo by utilizing its hollow structure to absorb sound energy is discussed here. The normal incidence absorption coefficient was measured based on the length and diameter of the bamboo, as well as different arrangement of the bamboo structure subjected to the incidence sound, namely, axial, transverse, and crossed-transverse arrangements. The trend of absorption coefficient appears in peaks and dips at equally spacing frequencies. For all arrangements the peak of absorption can reach above 0.8. Introducing an air gap behind the bamboo shifts the peak absorption to lower frequency. Covering the front surface of the absorber improves the sound absorption coefficient for axial arrangement by widening the frequency range of absorption also towards lower frequency range. The transverse arrangement is found to have average absorption coefficient peaks of 0.7 above 1.5 kHz. By arranging the bamboo structure with crossed-transverse arrangement, the suppressed absorption peaks in normal transverse arrangement can be recovered.

10

Próby odbiorowe systemów oddymiania z wykorzystaniem pomiaru zasięgu widzialności

Wróbel P., Ostapiuk Ł., Sałek P.

Materiały Budowlane

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2014

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nr 10

147--148

PL

W artykule zaprezentowano możliwości wykorzystania urządzeń do pomiaru zasięgu widzialności na potrzeby prób odbiorowych systemów oddymiania w budynkach, w celu umożliwienia oceny skuteczności ich działania. Dzięki zastosowaniu detektora homodynowego uzyskano dobrą dokładność pomiarową, którą zweryfikowano na stanowisku testowym. Przedstawiono również metodę weryfikacji dokładności pomiarów oraz przykładowe wyniki uzyskane w warunkach rzeczywistych.

EN

The article presents possibilities of using dedicated devices designed to measure a visibility range for acceptance tests of smoke ventilation systems in buildings in order to enable the evaluation of their operation efficiency. Good measurement accuracy was obtained thanks to employing a homodyne detector, which was then verified at an acceptance station. Furthermore, a method of validation of measurement accuracy has been described here along with exemplary results received in actual conditions.

11

Wpływ podciśnienia na właściwości akustyczne semiinteligentnych struktur granulowanych

Rutkowski M., Zalewski R.

Modelowanie Inżynierskie

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2013

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T. 17, nr 48

124--130

PL

Praca ta jest kolejnym etapem rozpoczętych kilka lat temu badań właściwości specjalnych struktur granulowanych. Poznane do tej pory cechy wspomnianych materiałów, m.in. wiedza o zmieniającej się wraz z podciśnieniem strukturze szczelnie zamkniętego granulatu, skłoniły autorów do sprawdzenia właściwości akustycznych tych materiałów, jak i możliwości ich sterowania. Przeprowadzone badania wpływu podciśnienia wytworzonego w próbce na współczynnik pochłaniania dźwięku przez próbki granulatów pokazują kolejne możliwości ich aplikacji w zastosowaniach inżynierskich.

EN

This research is the next step of study started few years ago, regarding the properties of Special Granular Structures. Some properties of granular structures, e.g. the changing of structure of the material, once it is submitted to internal under pressure in a sealed container, led the authors to believe that the acoustic properties may also change with pressure. Performed research regarding material sound absorption of investigated granular structures shows new potential possibilities of their application and confirms, that one can control acoustic properties of such structures.

12

Absorpcyjno-rozpraszające właściwości pigmentów stosowanych do powłok o dużym współczynniku odbicia promieniowania słonecznego

Zubielewicz M., Kamińska-Tarnawska E.

Przemysł Chemiczny

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2012

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T. 91, nr 8

1630-1634

PL

Oznaczone spektrofotometrycznie współczynniki odbicia pigmentów w zakresie promieniowania o długości fali 250–2500 nm wykorzystano do obliczenia współczynników absorpcji K i rozpraszania S, stosując własną procedurę opracowaną na podstawie teorii Kubelki i Munka (K-M). Stwierdzono, że na podstawie obliczonych współczynników K i S można dobierać pigmenty do otrzymywania powłok o dużym współczynniku odbicia promieniowania słonecznego, tzw. zimnych powłok.

EN

Twelve com. pigments were studied at wavelengths 250– 2500 nm for absorption and scattering coeffs. The calcn. was carried out by using authors’ own procedure developed on the basis of Kubelka-Munk theory. The calcd. coeffs. allowed for selecting pigments for coatings with high solar reflectivity. Spectrometric characteristics of the pigmented coating were presented graphically.

13

Simulation Model for the Absorption Coefficients of Double Layered Nonwovens

Liu X., Liu J., Su X.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 4 (93)

102--107

EN

In this paper, a more general sound absorption model for double layered nonwovens is proposed firstly by using the theory of C. Zwikker and C. W. Kosten for sound propagation through porous flexible media and sound propagation boundary conditions, and then a model simulation is detailed by changing the effective structure parameters of nonwovens. Double layered nonwovens composed of polyester fiber in the outer layer and nylon fiber in the inner layer is investigated in detail and the effects of acoustic parameters including the thickness and porosity of each layer on the absorption coefficient are analysed by numerical calculation, respectively. It shows that a double layered sound absorbing structure made of nonwovens has excellent sound absorption and can afford a sufficiently satisfying sound absorption level in a cared frequency range. In theory, this model can be used to calculate the absorption coefficients of double layered nonwovens composed of two different nonwoven materials . In practice, the sound absorption model for double layered nonwovens provides theoretical support for high performance sound absorber design and manufacture.

PL

Zaproponowano zastosowanie ogólnego modelu absorpcji dźwięku dla dwuwarstwowych dzianin opartego na teorii C. Zwikkera i C. W. Kostena. Model uwzględnia propagacje fal przez porowate odkształcalne media przyjmując odpowiednie warunki brzegowe charakterystyczne dla danego układu. Symulacja modelu została podzielona w zależności od zmiennych struktur obiektu. Dwuwarstwowe włókniny składały się z wewnętrznej warstwy włókien poliestrowych oraz zewnętrznej włókien nylonowych. Analizowano współczynniki absorpcji fal dźwiękowych badając wpływ grubości warstw oraz ich porowatości. Stwierdzono, że można uzyskać dobre właściwości tłumiące dla odpowiedniej konfiguracji warstw w określonym, ograniczonym zakresie częstotliwości. Za pomocą przedstawionego modelu można teoretycznie obliczyć współczynniki absorpcji dwuwarstwowych układów włóknin.

14

Zjawisko przezroczystości kompozytu w nieniszczących badaniach termicznych

Świderski W., Vavilov V., Hłosta P.

Pomiary Automatyka Kontrola

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2011

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R. 57, nr 10

1253-1255

PL

W nieniszczących badaniach termicznych typowym założeniem jest, że materiały kompozytowe są optycznie nieprzezroczyste zarówno dla promieniowania nagrzewania optycznego jak i promieniowania podczerwonego emitowanego przez badane obiekty. W artykule przedstawiono wyniki badań, w których wykazano, że niektóre kompozyty, takie jak tworzywa wzmocnione włóknami węglowymi (CFRP) i szklanymi (GFRP) oraz i inne są częściowo przezroczyste dla promieniowania nagrzewającego w trakcie badań termicznych. Dlatego to zjawisko powinno być uwzględnione kiedy określane są ograniczenia w wykrywaniu defektów metodami stosowanymi w tych badaniach. Wyniki badań eksperymentalnych pokazały, że wpływ przezroczystości kompozytów na wyniki nieniszczących badań termicznych może być znaczący co wskazuje, że ten problem powinien być dokładnej przebadany.

EN

Most available mathematical models in thermal nondestructive testing (NDT) assume that solid materials under test are not transparent for both optical radiation of a heater and infrared radiation emitted by the very material. The authors' preliminary study on composites showed that the statement above was not absolutely true even in the case of some presumably opaque composites, such as Carbon Fiber Reinforced Plastic (CFRP). There was assumed that the propagation of optical radiation through composites is governed by the Bouguer's law (Eq. 1). Values of were experimentally determined by Eq. (2) for CFRP, Glass Fiber Reinforced Plastic (GFRP) and ceramic samples. Values of were evaluated by using the experimental setup shown in Fig. 1. The rear-surface response of a thin aluminum (Al) plate is fairly precisely described by the following well-known expression (heating an adiabatic plate with a Dirac pulse) (Eq. 3). The time evolution of the rear-surface response of a 1 mm-thick Al plate according to Eq. (3) is shown in Fig. 1. The corresponding experimental curve was slower than the theoretical one due to relatively low acquisition frequency of the IR imager used (25 Hz). However, only a 'stationary' (at about 1 s after the flash) excess temperature T value wasmeasured in the experiment to calculate . The experiment result is presented in Table 1. It was found that a single circular flash tube used in the experiment produced 8950 W/m2 at the plane where the Al plate was placed. This value matches well other data obtained with this flash tube. To evaluate the absorption coefficient , the plates made of the above-mentioned composite were placed between the flash tube and the Al plate, and the rear-surface excess temperature of the Al plate was measured in about 1 s (see the test sketch in Fig. 2 and the experimental results in Table 1). It is worth mentioning that, in the considerations above, the spectral composition of the heating radiation is not taken into account. It is obvious that the major energy of flash tubes is concentrated in the visible range of optical radiation. Intuitively, it seems that the measured transparency of composites is much higher than expected. Therefore, the influence of the composite transparency on the results of thermal NDT may be significant, thus this topic deserves further investigations.

15

Modyfikacja zasad koordynacji izolacji w sieciach wysokiego napięcia w aspekcie ekonomicznym

Skomudek W.

Przegląd Elektrotechniczny

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2010

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R. 86, nr 11b

1-4

PL

Szybkozmienne zakłócenia elektromagnetyczne w sieci wysokiego napięcia przemieszczające się w postaci fal elektromagnetycznych stanowią poważne zagrożenie dla izolacji bądź układów izolacyjnych urządzeń służących do wytwarzania, przesyłu, rozdziału i użytkowania energii elektrycznej. Rozważania w artykule koncentrują się na wnioskach wynikających z badań i przeprowadzonych przez autora analiz stanowiących podstawę do dalszego racjonalnego działania w celu modyfikacji zasad koordynacji izolacji, prowadzącej między innymi do uzyskania rezultatów ekonomicznych.

EN

Fast-variable electromagnetic interference in the form of electromagnetic wave in power networks poses serious hazard to insulation of devices used for generation, transmission, distribution and consumption of electrical energy. Considerations in the article focus on the conclusions from researches and analyses by the author supported, which are the basis for modification of insulation coordination, conduct to get economic effects.

16

GEANT4 simulation of implantation profiles for positrons injected in solids from radioactive sources 22Na and 68Ge/68Ga

Horodek P., Dryzek J.

Nukleonika

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2010

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Vol. 55, No. 1

17-19

EN

We calculated theoretically the mass absorption coefficients for positrons emitted from the commonly used sources 22Na and 68Ge/68Ga in numerous materials. For this purpose, we used the tool kit GEANT4 which allows to generate the implantation profile. An excellent agreement between the experimental profile and the calculated one was achieved. The calculated values of the mass absorption coefficients coincide well with the experimental values determined by the DSIP method.

17

Distribution of electronic states in amorphous Zn-P thin films on the basis of optical measurements

Jarzabek B., Weszka J., Cisowski J.

Optica Applicata

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2008

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Vol. 38, nr 3

575-583

EN

Transmission and fundamental reflectivity studies, completed on amorphous Zn-P thin films, allowed us to obtain parameters describing the fundamental absorption edge, i.e., the optical pseudogap EG, Urbach energy EU and exponential edge parameter ET. All these data, together with the results of earlier transport measurements, have been utilized in developing simple models of electronic structure (distribution of electronic states) for amorphous Zn-P thin films of two compositions, i.e., Zn57P43 (near stoichiometry of Zn3P2) and Zn32P68 (near stoichiometry of ZnP2).

18

New materials and ideas to be used in adiabatic engines

Jaskólski J., Krzyżak R.

Journal of KONES

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2004

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Vol. 11, No. 1-2

288-294

EN

This note concerns several topics. Firstly, a review of some less-known topics regarding the contemporary knowledge on TBC and piston caps is given. Then, it turns out that almost unknown New Periodic System of Elements can be of assistance to predict several properties of new TBC materials. Theoretically, there exist a possibility to join Si-AL-piston alloy with yttria-stabilised zirconia (and the like) by means of feId spars (plagioclase). The latter do not attain to melting temperature and can be arrested within the alloy. A shortened integral optical equation in the manner of inverse problem was used to compute the temperature drop accros the piston cap's layers. The YSZ layer operating in this hypothetical engine gave 517.5 graduate K drop, whereas the feldspar gave about 100-50graduate K temperature drop per mm. This arrangement would give minimised radiation and more or less 'cold' engine(piston). Perhaps, oxides of the thalium-sesquioxide-type structure would be better to stick to metal than the commonly used ones.

19

Spectral light absorption by yellow substance in the Kattegat-Skagerrak area

Hojerslev N. K., Aas E.

Oceanologia

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2001

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No. 43 (1)

39-60

EN

More than 1500 water samples were taken from the Kattegat, the Skagerrak and adjacent waters. The value of the absorption coefficient of yellow substance at 310 nm was found to vary from 0.06 to 7.4 m-1 in the open coastal waters, with a mean value of 1.3 m-1. The corresponding wavelength-averaged value (250-450 nm) of the semilogarithmic spectral slope of the coefficient ranges from 0.008 to 0.042 nm-1, and the mean value is 0.023 nm-1. Closer to river discharges, as in the fjords, the values of the slope seem to be more constant at around 0.0175 š 0.0015 nm-1. In this area the slope must then be known in order to compare absorption at different wavelengths or to model the yellow substance absorption.

20

Układ dwóch sfer integrujących do badania rozpraszania i absorpcji światła

Liebert A., Łukasiewicz P., Maniewski R.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2000

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Vol. 6, nr 3-4

73-80

PL

W pracy przedstawiono technikę pomiaru właściwości optycznych z wykorzystaniem układu dwóch sfer integrujących. Pomiar polega na oświetleniu badanej próbki skolimowanym światłem laserowym i oszacowaniu promieniowania reemitowanego przez badaną próbkę, promieniowania transmitowanego oraz transmisji skolimowanej. Pomiary te umożliwiają obliczenie współczynników absorpcji, rozpraszania oraz anizotropii badanego preparatu. Opisano budowę systemu pomiarowego z dwiema sferami integrującymi, uruchomionego w Instytucie Biocybernetyki i Inżynierii Biomedycznej PAN. Omówiono zasady prowadzenia pomiarów, wskazano na źródła błędów. Zaprezentowano wyniki pomiarów mleka jako płynu o właściwościach optycznych zbliżonych do tkanek żywych. Stwierdzono, że jest możliwe stosowanie roztworów mleka z dodatkiem absorbera do budowy fantomów tkanek.

EN

The measurements of optical properties of the tissue is important for development of optical diagnostic methods. In this paper we present the technique of optical properties measurement with the use of double-integrating spheres system. The measurement of total reflectance, total transmittance and collimated transmittance allows to calculate scattering, absorption and anisotropy coefficients. General principles of the measurement were presented. Also the sources of errors were pointed out. The double-integrating spheres system constructed in the Institute of Biocybernetics and Biomedical Engineering was described. The measurements of optical properties of the milk as a medium optically similar to human tissue were carried out. It was observed that the milk solutions with absorber allow to build optical phantoms of the human tissues.