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Number of results: 82
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Abstract

Studies conducted between December 20. 1978 and February 20. 1979 on Arctowski Station show that daily sums of total radiation ranged from 165.5 to 834.5 mWhr x cm2. Maximal mean hourly radiations were recorded from 12 to 14 hours (39.7—72.4 mWhr x cm2).

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Authors and Affiliations

Adam Krężel
Kazimierz Pęcherzewski
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Abstract

This paper deals with the problem of the effect of discretization level and certain other parameters characterizing the measurement setup on accuracy of the process of determination of the sound radiation efficiency by means of the Discrete Calculation Method (DCM) described by Hashimoto (2001). The idea behind DCM consists in virtual division of an examined sound radiating structure into rectangular elements each of which is further assumed to contribute to the total radiation effect in the same way as a rigid circular piston having the surface area equal to this of the corresponding virtual element and vibrating in an infinite rigid baffle. The advantage of the method over conventional sound radiation efficiency measurement techniques consists in the fact that instead of acoustic pressure values, source (plate) vibration velocity amplitude values are measured in a selected number of regularly distributed points. In many cases, this allows to determine the sound radiation efficiency with sufficient accuracy, especially for the low frequency regime. The key part of the paper is an analysis of the effect of discretization level (i.e. the choice of the number of points at which vibration amplitude measurements are to be taken with the use of accelerometers) on results obtained with the use of the method and their accuracy. The problem of determining an optimum level of discretization for given excitation frequency range is a very important issue as the labor intensity (time-consuming aspect) of the method is one of its main flaws. As far as the technical aspect of the method is concerned, two different geometrical configurations of the measurement setup were tested.
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Authors and Affiliations

Karolina Kolber
Anna Snakowska
Michał Kozupa
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Abstract

Ionizing radiation applied on food eliminates harmful microorganisms, prevents sprouting and delays ripening. All methods for detection of irradiated food are based on physical, chemical, biological or microbiological changes caused by the treatment with ionizing radiation. When minerals are exposed to ionizing radiation, they accumulate radiation energy and store it in the crystal lattice, by which some electrons remain trapped in the lattice. When these minerals are exposed to optical stimulation, trapped electrons are released. The phenomenon, called optically stimulated luminescence or photostimulated luminescence, occurs when released electrons recombine with holes from luminescence centers in the lattice, resulting in emission of light with certain wavelengths.

In this paper, the results of measurements performed on seven different samples of herbs and spices are presented. In order to make a comparison between luminescence signals from samples treated with different doses, unirradiated samples are treated with Co-60 with doses of 1 kGy, 5 kGy and 10 kGy. In all cases it was shown that the higher the applied dose, the higher the luminescence signal.

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Authors and Affiliations

Ivana Sandeva
Hristina Spasevska
Margarita Ginovska
Lihnida Stojanovska-Georgievska
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Abstract

The global solar radiation is the origin for all environmental processes on the earth and the majority of energy sources are derived from it. The data of solar radiation are required for the design and the study of solar application systems. The more important is the quality of the solar radiation which is defined by the maximum work can be provided by the solar radiation. This quality is measured by the exergy content of a solar radiation. In the present work, a universal pattern has been built to provide a prediction of solar exergy dependently to the geographic location. Fitting models have been developed for exergy account depending on geographic location, based on the linear, quadratic, cubic, logarithmic, exponential, power regression. The Petela model is adopted from literature for exergetic efficiency accounting of solar radiation. The global solar radiation according to ASHRAE model is expressed dependently of the cosine of zenith angle. The developed model is applied on Tunisia regions to predict exergy solar potential. The studied regions are classified regarding the exergy account, high, medium and low solar exergy locations. Results show that generally the solar radiation shows a low degree of exergy content, about 7% of difference.
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Bibliography

[1] Li L., Lin J., Wu N., Xie S., Meng C., Zheng Y., Wang X., Zhao Y.: Review and outlook on the international renewable energy development. Energ. Built Environ. 3(2020), 2, 2666–1233.
[2] Papadis E., Tsatsaronis G.: Challenges in the decarbonization of the energy sector. Energy 205(2020), 118025.
[3] Hosseini S.E., Wahid M.A.: Renewable and sustainable energy reviews hydrogen production from renewable and sustainable energy resources: Promising green energy carrier for clean development. Renew. Sust. Energ. Rev. 57(2016), 850–866.
[4] Multon B., Gaël R., Ruellan M., Ahmed H.B.: Situation énergétique mondiale à l’aube du 3ème millénaire. Perspectives offertes par les ressources renouvelables. La Revue 3EI SEE (2004), 20–33.
[5] Notton G.: Solar radiation for energy applications. In: Encyclopedia of Sustainable Technologies (A.M. Abraham, Ed.). Elsevier, 2017, 339–356.
[6] Sanan T. Mohammad, Hussain H. Al-Kayiem, Mohammed A. Aurybi, Ayad K. Khlief: Measurement of global and direct normal solar energy radiation in Seri Iskandar and comparison with other cities of Malaysia. Case Stud.Therm. Eng. 18, (2020), 100591.
[7] Cavaco A., Canhoto P., Pereira M.C.: Corrigendum to “Procedures for solar radiation data gathering and processing and their application to DNI assessment in southern Portugal” [Renew. Energ. 163(2021) 2208–2219]. Renew. Energ. 168(2021), 1405.
[8] Yorukoglu M., Celik A.N.: A critical review on the estimation of daily global solar radiation from sunshine duration. Energ. Convers. Manage. 47(2006), 15–16, 2441–2450.
[9] Bakirci K.: Correlations for estimation of daily global solar radiation with hours of bright sunshine in Turkey. Energy 34(2009), 4, 485–501.
[10] Çengelet Y.A. Boles M.A.: Thermodynamics. An Engineering Approach (5th Edn.). McGraw-Hill, 2005.
[11] Dincer I., Rose M.A. (Eds.): Exergy, Energy, Environment, and Sustainable Development (3rd Edn.). Elsevier, 2021, 61–89.
[12] Ziebik A.: Thermodynamical motivation of the Polish energy policy. Arch. Thermodyn. 33(2012), 4, 3–21.
[13] Chu S.X., Liu L.H.: Analysis of terrestrial solar radiation exergy. Sol. Energy 83(2009), 8, 1390–1404.
[14] Candau Y.: On the exergy of radiation. Sol. Energy 75(2003), 3, 241–247.
[15] Gueymard Ch.A.: The sun’s total and spectral irradiance for solar energy applications and solar radiation models. Sol. Energy 76(2004), 4, 423–453.
[16] Kabelac S.: Exergy of solar radiation. Int. J. Energy Technol. Policy 3(2005), 1–2, 115–122.
[17] Joshi A.S., Dincer I., Reddy B.V: Development of new solar exergy maps. Int. J. Energ. Res. 33(2009), 8, 709–718.
[18] Alta D., Ertekin C., Evrendilek F.: Quantifying spatio-temporal dynamics of solar radiation exergy over Turkey. Renew. Energ. 35(2010), 12, 2821–2828.
[19] Jiménez-Muñoz J.C., Sobrino J.A., Mattar C.: Recent trends in solar exergy and net radiation at global scale. Ecol. Model. 228(2012), C, 59–65.
[20] Hepbasli A., Alsuhaibani Z.: Estimating and comparing the exergetic solar radiation values of various climate regions for solar energy utilization. Energ. Source. Part A 36(2014) 7, 764–773.
[21] Uçkan I.: Exergy analysis of solar radiation based on long term for Van city. J. Polytech. 20(2017), 3, 579–584.
[22] Petela R.: Energy of heat radiation. J. Heat Transfer 86(1964), 187–192.
[23] Spanner D.C.: Introduction to Thermodynamics. Academic Press, London, 1964.
[24] Jeter S.M.: Maximum conversion efficiency for the utilization of direct solar radiation. Sol. Energ. 26(1981), 231–236.
[25] Arslanoglu N.: Empirical modeling of solar radiation exergy for Turkey. Appl. Therm. Eng. 108(2016), 1033–1040.
[26] Jamil B., Bellos E.: Development of empirical models for estimation of global solar radiation exergy in India. J. Clean. Prod. 207(2019), 1–16.
[27] Khorasanizadeh H., Sepehrnia M.: Solar exergy evaluation and empirical model establishment; case study: Iran. Heliyon 6(2020), 12, 2405–8440, e05638.
[28] Lounissi D., Bouaziz N.: Exergetic analysis of an absorption/compression refrigeration unit based on R124/DMAC mixture for solar cooling. Int. J. Hydrog. Energ. 42(2017), 13, 8940–8947.
[29] Simpson A.P.: Decision making in energy: Advancing technical, environmental, and economic perspectives. PhD thesis, Stanford Univ. 2010, 28168075. https://www.proquest.com/openview/6ee7749bfe128753d88ba805856d03b8/1?pqorigsite= gscholar&cbl=18750&diss=y (accessed 10 May 2010).
[30] Brand Correa L.I.: Exergy and useful work analysis as a tool for improved energy policy making: The case of the Colombian energy sector. MSc. thesis, Univ. of Edinburgh, 2014, https://www.doi.org/10.13140/RG.2.1.4523.6089.
[31] Sciubba E.: Beyond thermoeconomics? The concept of extended exergy accounting and its application to the analysis and design of thermal systems. Exerg. Int. J. 1(2001), 2, 68–84.
[32] Abd Elbar A.R., Yousef M.S., Hassan H.: Energy, exergy, exergoeconomic and enviroeconomic (4E) evaluation of a new integration of solar still with photovoltaic panel. Clean. Prod. 233(2019), 665–680.
[33] Luminosu I., Fara L.: Determination of the optimal operation mode of a flat solar collector by exergetic analysis and numerical simulation. Energy 30(2005), 5, 731– 747.
[34] Sala Lizarraga J.M.P., Picallo-Perez A.: Exergy Analysis and Thermoeconomics of Buildings. Butterworth-Heinemann, 2020.
[35] Ghritlahre H.K., Sahu P.K.: A comprehensive review on energy and exergy analysis of solar air heaters. Arch. Thermodyn. 41(2020), 3, 183–222.
[36] Ghritlahre H.K.: An experimental study of solar air heater using arc shaped wire rib roughness based on energy and exergy analysis. Arch. Thermodyn. 42(2021), 3, 115–139.
[37] Sobhnamayan F., SarhaddF. i, Alavi M.A., Farahat S., Yazdanpanahi J.: Optimization of a solar photovoltaic thermal (PV/T) water collector based on exergy concept. Renew. Energ. 68(2014), 356–365.
[38] Hossain S., Chowdhur H., Chowdhury T., Ahamed J.U., Saidur R., Sait S.M., Rosen M.A.: Energy, exergy and sustainability analyses of Bangladesh’s power generation sector. Energ. Rep. 6(2020), 868–878.
[39] Chowdhury H., Chowdhury T., Chowdhury P., Islam M., Saidur R., Sait S.M.: Integrating sustainability analysis with sectoral exergy analysis: A case study of rural residential sector of Bangladesh, Energ. Buildings 202(2019), 109397.
[40] Cornelissen R.L.: Thermodynamics and sustainable development. PhD thesis, Univ. of Twente, 1997.
[41] Maruf M.H., Rabbani M., Ashique R.H., Islam M.T., Nipun M.K., Haq M.A.U., Al Mansur, Shihavuddin A.S.M.: Exergy based evaluation of power plants for sustainability and economic performance identification. Case Stud. Therm. Eng. 28(2021), 101393.
[42] Rosen M.A., Dincer I., Kanoglu M.: Role of exergy in increasing efficiency and sustainability and reducing environmental impact. Energy Policy 36(2008), 128–137.
[43] Zisopoulos F.K., Rossier-Miranda F.J., van der Goot A.J., Boom R.M.: The use of exergetic indicators in the food industry – A review. Crit. Rev. Food Sci. Nutrit. 57(2017), 197–211.
[44] Hepbasli A.: A key review on exergetic analysis and assessment of renewable energy resources for a sustainable future. Renew. Sust. Energ. Rev. 12(2008), 593–661.
[45] Sudhakar K., Tulika Srivastava: Energy and exergy analysis of 36 W solar photovoltaic module. Int. J. Amb. Energ. 35(2014), 1, 51–57.
[46] Press W.H.: Theoretical maximum for energy from direct and diffuse sunlight. Nature 264(1976), 734–735.
[47] Landsberg P.T., Tonge G.: Thermodynamics of the conversion of diluted radiation. J. Phys. A-Math. Gen. 12(1979), 4, 551–562.
[48] Parrott J.E.: Theoretical upper limit to the conversion efficiency of solar energy. Sol. Energy 21(1978), 3, 227–229.
[49] Parrott J.E.: A letter. Sol. Energy 22(1979), 6, 572–573.
[50] Kabelac S.: A new look at the maximum conversion efficiency of blackbody radiation. Sol. Energy 46(1991), 4, 231–236.
[51] Millan M.I., Hernandez F., Martin E.: Available solar exergy in an absorption cooling process. Sol. Energy 56(1996), 6, 505–511.
[52] Würfel P.: Thermodynamic limitations to solar energy conversion. Physica E 14(2002), 1–2, 18–26.
[53] Bejan A.: Advanced Engineering Thermodynamics. Wiley, New York, 2006.
[54] Petela R.: Exergy of undiluted thermal radiation. Sol. Energy 74(2003), 6, 469–488.
[55] ASHRAE. Handbook of Fundamentals. American Society of Heating, Refrigeration, and Air Conditioning Engineers, New York, 1979.
[56] Solar Position Calculator. https://gml.noaa.gov/grad/solcalc/azel.html (accessed 10 May 2021).
[57] Khorasanizadeh H., Mohammadi K., Mostafaeipour A.: Establishing a diffuse solar radiation model for determining the optimum tilt angle of solar surfaces in Tabass, Iran. Energ. Convers. Manage. 78(2014), 805–814.
[58] Despotovic M., Nedic V., Despotovic D., Cvetanovic S.: Review and statistical analysis of different global solar radiation sunshine models. Renew. Sust. Energ. Rev.52(2015), 1869–1880.
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Authors and Affiliations

Khaoula Daghsen
1 2
Dorra Lounissi
2
Nahla Bouaziz
2

  1. University of Monastir, National Engineering School of Monastir, Rue Ibn El Jazzar, Monastir 5000, Rue Ibn Jazzar, Monastir 5035, Tunisia
  2. University of Tunis El Manar, National Engineering School of Tunis, Energy and Environment Laboratory LR21ES09, ENIT. BP 37, Le Belvedere 1002
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Abstract

The evaluation of complex radiation impedance for a square piston source on an infinite circularcylindrical baffle is associated to the Greenspon-Sherman formulation for which novel evaluation methods are proposed. Unlike existing methods results are produced in a very wide range of frequencies and source semi-angles with controllable precision. For this reason closed-form expressions are used to describe the truncation errors of all integrals and infinite sums involved. Impedance values of increased accuracy are also provided in tabulated form for engineering use and a new radiation mass-load model is derived for low-frequencies.

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Authors and Affiliations

John L. Valacas
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Abstract

We talk to Prof. Piotr Homola from the Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences in Kraków, about his search for cosmic ray ensembles.

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Authors and Affiliations

Piotr Homola
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Abstract

The subject of the article is aspects of PV modules and cells measurement, with the use of natural sunlight. A light source is an important element during calibration and measurements of solar cells and modules. All designers of artificial light sources try to recreate natural light using so called measurement tables. The correctly performed measurement, i.e. meeting all the appropriate atmospheric conditions, guarantees obtaining the result with the use of a reference spectrum. The article has two main aims. The first aim of the article is to answer the question asked earlier - if the sunlight spectrum registered in appropriate conditions is so good that it serves as the reference spectrum - then, in practice, during measurements carried out with its use, certain problems occur regarding the correct measurement results or their interpretation. The second aim regards presenting detailed numeric procedures in order to enable readers to associate air mass with geographical coordinates and Local Solar Time of their study/laboratory location. Moreover, having the data from their local meteorological station, they will be able to estimate the occurrence of the measurement spectral error of the tested cell/module not only from the group referred to in the article but also for others, for which they have a dedicated characteristics of spectral response.

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Authors and Affiliations

T. Rodziewicz
M. Rajfur
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Abstract

This paper presents the results of measurements of the operation of a photovoltaic system, connected to the power grid. The intensity of solar radiation and the ambient temperature in the location of the installation were simultaneously recorded in different weather conditions on selected days throughout the year. For the combined results the analysis of correlation in terms of efficiency of individual exemplary photovoltaic installation was conducted.
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Authors and Affiliations

Mariusz Sarniak
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Abstract

Solar radiation (Rs) is an essential input for estimating reference crop evapotranspiration, ETo. An accurate estimate of ETo is the first step involved in determining water demand of field crops. The objective of this study was to assess the ac-curacy of fifteen empirical solar radiations (Rs) models and determine its effects on ETo estimates for three sites in humid tropical environment (Abakaliki, Nsukka, and Awka). Meteorological data from the archives of NASA (from 1983 to 2005) was used to derive empirical constants (calibration) for the different models at each location while data from 2006 to 2015 was used for validation. The results showed an overall improvement when comparing measured Rs with Rs determined us-ing original constants and Rs using the new constants. After calibration, the Swartman–Ogunlade (R2 = 0.97) and Chen 2 models (RMSE = 0.665 MJ∙m–2∙day–1) performed best while Chen 1 (R2 = 0.66) and Bristow–Campbell models (RMSE = 1.58 MJ∙m–2∙day–1) performed least in estimating Rs in Abakaliki. At the Nsukka station, Swartman–Ogunlade (R2 = 0.96) and Adeala models (RMSE = 0.785 MJ∙m–2∙day–1) performed best while Hargreaves–Samani (R2 = 0.64) and Chen 1 mod-els (RMSE = 1.96 MJ∙m–2∙day–1) performed least in estimating Rs. Chen 2 (R2 = 0.98) and Swartman–Ogunlade models (RMSE = 0.43 MJ∙m–2∙day–1) performed best while Hargreaves–Samani (R2 = 0.68) and Chen 1 models (RMSE = 1.64 MJ∙m–2∙day–1) performed least in estimating Rs in Awka. For estimating ETo, Adeala (R2 =0.98) and Swartman–Ogunlade models (RMSE = 0.064 MJ∙m–2∙day–1) performed best at the Awka station and Swartman–Ogunlade (R2 = 0.98) and Chen 2 models (RMSE = 0.43 MJ∙m–2∙day–1) performed best at Abakaliki while Angstrom–Prescott–Page (R2 = 0.96) and El-Sebaii models (RMSE = 0.0908 mm∙day–1) performed best at the Nsukka station.

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Authors and Affiliations

Emeka Ndulue
Ikenna Onyekwelu
Kingsley Nnaemeka Ogbu
Vintus Ogwo
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Abstract

Progress in UV treatment applications requires new compact and sensor constructions. In the paper a hybrid (organic-inorganic) rare-earth-based polymeric UV sensor construction is proposed. The efficient luminescence of poly(methyl) methacrylate (PMMA) matrix doped by europium was used for testing the optical sensor (optrode) construction. The europium complex assures effective luminescence in the visible range with well determined multi-peak spectrum emission enabling construction of the optrode. The fabricated UV optical fibre sensor was used for determination of Nd:YAG laser intensity measurements at the third harmonic (355 nm) in the radiation power range 5.0-34.0 mW. The multi-peak luminescence spectrum was used for optimization of the measurement formula. The composition of luminescent peak intensity enables to increase the slope of sensitivity up to −2.8 mW-1. The obtained results and advantages of the optical fibre construction enable to apply it in numerous UV detection systems.

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Authors and Affiliations

Piotr Miluski
Marcin Kochanowicz
Jacek Żmojda
Dominik Dorosz
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Abstract

The operating principles of RFID antennas should be considered differently than it is applied in the classical theory of radio communication systems. The procedure of measuring the radiation pattern of antennas that could be applied to RFID transponders operating in the UHF band is seldom discussed correctly in the scientific literature. The problem consists in the variability of the RFID chip impedance that strongly influences measurement results. The authors propose the proper methodology for determining the radiation pattern with respect to an individual transponder as well as an electronically tagged object. The advantage of the solution consists in the possibility of using components of different measuring systems that are available in typical antenna laboratories. The proposed procedure is particularly important in terms of parameter validation - the identification efficiency and costs of an RFID system implementation can be evaluated properly only on the basis of real values of considered parameters.

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Authors and Affiliations

Piotr Jankowski-Mihułowicz
Mariusz Węglarski
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Abstract

The proper designing of PV systems requires the use of advanced building energy simulation techniques. It allows to design the best position of the PV array, as well as the right quantity of produced energy in different cases. On the other hand the PV efficiency is not only a constant value but changes according to temperature and solar radiation. This paper is devoted to estimate the simultaneous effect of both weather factors on PV efficiency. The task was achieved by numerical simulation and ESP-r software. Computer simulations have been carried out with the use of the Typical Meteorological Year data for Warsaw (52°N 21°E). The greatest influence of temperature on the efficiency of solar energy conversion was observed for crystalline silicon cells. The influence of the boundary conditions assumed in the study is ignored for amorphous silicon cells in the summer period and regardless of the material type in the winter period.

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Authors and Affiliations

D. Heim
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Abstract

The paper considers method of determination of solar radiation amount falling on arbitrarily oriented surface of a structure. Provided method allows calculation of influence of structure’s geographical coordinates, spatial orientation of structure’s surface, day of year and time of day on received amount of solar radiation. The method is intended for determination of thermal stresses and deformations of sheet steel structures caused by action of direct solar radiation. Examples show usage of provided method.

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O.I. Kordun
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Abstract

This article presents the results of observations of selected fluxes of the radiation balance in north-western Spitsbergen in the years from 2010 to 2014. Measurements were taken in Ny-Ålesund and in the area of Kaffiøyra, on different surface types occurring in the Polar zone: moraine, tundra, snow and ice. Substantial differences in the radiation balance among the various types of surface were observed. The observations carried out in the summer seasons of 2010-2014 in the area of Kaffiøyra demonstrated that the considerable reflection of solar radiation on the Waldemar Glacier (albedo 55%) resulted in a smaller solar energy net income. During the polar day, a diurnal course of the components of the radiation balance was apparently related to the solar elevation angle. When the sun was low over the horizon, the radiation balance became negative, especially on the glacier. Diurnal, annual and multi-annual variations in the radiation balance have a significant influence on the functioning of the environment in polar conditions.
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Authors and Affiliations

Marek Kejna
Marion Maturilli
Andrzej Araźny
Ireneusz Sobota
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Abstract

This paper presents the first results of measurements of global solar radiation, albedo, ground surface and 2−m air temperature, relative humidity, and wind speed and direction carried out in the central part of Spitsbergen Island in the period 2008–2010. The study site was located on the coastal ice−free zone of Petuniabukta (north−western branch of Billefjorden), which was strongly affected by local topography, character of the ground surface, and sea ice extent. Temporal analysis of the selected meteorological parameters shows both strong seasonal and inter−diurnal variation affected by synoptic−scale weather systems, channelling and drainage effects of the fjords and surrounding glaciers. The prevailing pattern of atmospheric circulation primarily determined the variation in global solar radiation, wind speed, ground surface and 2−m air temperatures. Furthermore, it was found that thermal differences between Petuniabukta and the nearest meteorological station (Svalbard Lufthavn) differ significantly due to differences in sea ice concentrations and ice types in the fjords during the winter and spring months.
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Authors and Affiliations

Kamil Láska
Denisa Witoszová
Pavel Prošek
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Abstract

In the Canary Islands, groundwater is the main source of drinking water. Groundwater mines have been the system used by the engineers of the archipelago to collect water from the ground. The Canary Islands are volcanic with soils characterized by being rich in uranium, the disintegration of which gives rise to radon gas. In this study, radon gas levels in the mines on two islands of the archipelago have been measured to study exposure to this gas in the galleries. Results show values much higher than the European regulatory limit concentrations.

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Authors and Affiliations

Juan C. Santamarta
Luis Enrique Hernández Gutiérrez
Jesica Rodríguez Martín
Lina Pérez
Rafael J. Lario Bascones
Ángel Morales González Moro
Noelia Cruz Pérez
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Abstract

A novel method of active noise control using adaptive radiation sound sources is investigated. A finite element model of a modal enclosed sound field is excited harmonically, representing a noise field in the low-frequency range. The control sources are comprised of elementary dipole sources for which the driving signals are adjusted by an optimization method. Two set-up cases of the proposed compound sources are investigated. The coupling of the control sources with the modal sound field is discussed. The simulated performance of the proposed method is compared with that of a system with distributed simple sources and the results show the effectiveness of the sources with adaptive radiation for active noise control in small enclosures.

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Authors and Affiliations

Marios Giouvanakis
Christos Sevastiadis
George Papanikolaou
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Abstract

The polycyclic musk fragrances AHTN (Tonalide) and HHCB (Galaxolide) are the most common components of cosmetics and detergents. Use of AHTN and HHCB per year (in the USA and in EU) was estimated at 1500 Mg and 3800 Mg, respectively. Because of their persistent character, musk compounds are introduced into environment mostly via urban sewage treatment plant effluents. The aim of the presented research was to assess the receptivity of AHTN and HHCB to the oxidation by means of UV-radiation and in the UV /H2O2 process. The investigations were performed in the treated wastewater and the drinking water. After 8 minutes, in all experiments performed on drinking water, the degradations of AHTN and HHCB in the range of 99% were observed. The removal of HHCB from wastewater by means of UV radiation exceeded up 93% (after 8 minutes of the process), whereas the disappearance degree of this compound in wastewater, after only 3 minutes ofUV/H2O2 process, exceeded 99%. The degradation constant rate for AHTN in drinking water using UV radiation was equal to 0.764 rnin' when the degradation rate ofHHCB was estimated at 0.634 min'. In the wastewater, the coefficient rate ofHHCB degradation by means ofUV/H2O2 was nearly 4.5 times higher (1.580 min') in comparison to the value obtained by direct photolysis of HHCB (0.354 min').
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Authors and Affiliations

Ewa Felis
Alfredo C. Alder
Joanna Surmacz-Górska
Korneliusz Miksch
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Abstract

On the basis of a year-long series of actinometric measurements performed in the vicinity of Polish Polar Station at Hornsund, this paper presents the characteristic of the value of solar radiation incoming at the active surface, of absorbed and net radiation. The maximum intensity of the direct solar radiation was 822 Wm-2, the annual sum total of total radiation was 2611 MJm-2, whereas the mean yearly albedo was 59%. The zero-crossing of the 24-hour sums of the net radiation towards negative values occurred at the turn of September and October.

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Authors and Affiliations

Bronisław Głowicki
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Abstract

Cylindrical shells made of composite material form one of the major structural parts in aerospace structures. Many of them are acoustically thick, in which the ring frequencies are much higher than their critical frequencies. In this work, sound radiation behaviour of acoustically thick composite cylinders is presented. Based on the structural and acoustic wave number diagrams, the modal average radiation resistances in the frequency band of interest are theoretically determined. The structural wavenumbers are determined considering transverse shear deformation. The results show lesser sound radiation between the critical and ring frequencies, and significant sound radiation near the ring frequency and beyond. In the absence of the present results the radiation efficiency is considered to be unity at all frequencies beyond the critical frequency, including near the ring frequency. The radiation resistances of the same cylinder are determined experimentally and they are in very good agreement with the theoretical estimates. As part of this investigation, an expression for determining the ring frequency of composite cylinder is also presented.
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Bibliography

1. Bordoni P.G., Gross W. (1948), Sound radiation from a finite cylinder, Journal of Mathematics and Physics, 27(1–4): 242–252, doi: 10.1002/sapm1948271241.
2. Burroughs C.B. (1984), Acoustic radiation from fluid-loaded infinite circular cylinders with doubly periodic ring supports, The Journal of the Acoustical Society of the America, 75(3): 715–722, doi: 10.1121/1.390582.
3. Cao X., Hua H., Ma C. (2012), Acoustic radiation from shear deformable stiffened laminated cylindrical shells, Journal of Sound and Vibration, 331(3): 651–670, doi: 10.1016/j.jsv.2011.10.006.
4. Cox T.J., D’Antonio P. (2004), Acoustic Absorbers and Diffusers: Theory, Design and Application, New York: CRC Press.
5. Fahy F.J. (1969), Vibration of containing structure by sound in the contained fluid, Journal of Sound and Vibration, 10(3): 490–512, doi: 10.1016/0022-460x(69)90228-4.
6. Fahy F.J. (1970), Response of a cylinder to random sound in the contained fluid, Journal of Sound and Vibration, 13(2): 171–194, doi: 10.1016/s0022-460x(70)81172-5.
7. Fyfe K.R., Ismail F. (1989), An investigation of the acoustic properties of vibrating finite cylinders, Journal of Sound and Vibration, 128(3): 361–375, doi: 10.1016/0022-460x(89)90780-3.
8. Ghinet S., Atalla N., Osman H. (2006), Diffuse field transmission into infinite sandwich composite and laminate composite cylinders, Journal of Sound and Vibration, 289(4–5): 745–778, doi: 10.1016/j.jsv.2005.02.028.
9. Josephine Kelvina Florence S., Renji K., Subramanian K. (2018), Modal density of honeycomb sandwich composite cylindrical shells considering transverse shear deformation, International Journal of Acoustics and Vibration, 23(3): 83–92, doi: 10.20855/ijav.2018.23.11241 .
10. Laulagnet B., Guyader J.L. (1989), Modal analysis of a shell’s acoustic radiation in light and heavy fluids, Journal of Sound and Vibration, 131(3): 397–415, doi: 10.1016/0022-460x(89)91001-8.
11. Le Bot A., Cotoni V. (2010), Validity diagrams of statistical energy analysis, Journal of Sound and Vibration, 329(2): 221–235, doi: 10.1016/j.jsv.2009.09.008.
12. Lin T.R., Mechefske C., O’Shea P. (2011), Characteristics of modal sound radiation of finite cylindrical shells, Journal of Vibration and Acoustics, 133(5): 051011–051016, doi: 10.1115/1.4003944.
13. Lyon R.H. (1975), Statistical Energy Analysis of Dynamical Systems: Theory and Applications, Cambridge, MA: MIT Press.
14. Manning J.E., Maidanik G. (1964), Radiation properties of cylindrical shells, The Journal of the Acoustical Society of the America, 36(9): 1691–1698, doi: 10.1121/1.1919266.
15. Miller V.J., Faulkner L.L. (1983), Prediction of aircraft interior noise using the statistical energy analysis method, Journal of Vibration,Acoustics,Stress and Reliability in Design, 105(4): 512–518, doi: 10.1115/1.3269136.
16. Norton M.P. (1989), Fundamentals of Noise and Vibration Analysis for Engineers, England: Cambridge University Press.
17. Qiao Y., Chen H.B., Luo J.L. (2013), Estimation of shell radiation efficiency using a FEM-SmEdA algorithm, Journal of Vibroengineering, 15(3): 1130–1146.
18. Ramachandran P., Narayanan S. (2007), Evaluation of modal density, radiation efficiency and acoustic response of longitudinally stiffened cylindrical shell, Journal of Sound and Vibration, 304(1–2): 154–174, doi: 10.1016/j.jsv.2007.02.020.
19. Renji K., Josephine Kelvina Florence S. (2020), Critical frequencies of composite cylindrical Shells, International Journal of Acoustics and Vibration, 25(1): 79–87, doi: 10.20855/ijav.2020.25.11572.
20. Renji K., Josephine Kelvina Florence S., Sameer Deshpande (2019), Characteristics of in-plane waves in composite plates, International Journal of Acoustics and Vibration, 24(3): 458–466, doi: 10.20855/ijav.2019.24.31290.
21. Renji K., Josephine Kelvina Florence S., Sameer Deshpande (2020), An Experimental investigation of modal densities of composite honeycomb sandwich cylindrical shells, International Journal of Acoustics and Vibration, 25(1): 112–120, doi: 10.20855/ijav.2020.25.11626.
22. Renji K., Nair P.S., Narayanan S. (1998), On acoustic radiation resistance of plates, Journal of Sound and Vibration, 212(4): 583–598, doi: 10.1006/jsvi.1997.1438.
23. Reynolds D.D. (1981), Engineering Principles of Acoustics Noise and Vibration, Boston, MA: Allyn and Bacon.
24. Runkle C.J., Hart F.D. (1969), The Radiation Resistance of Cylindrical Shells, NASA CR-1437.
25. Squicciarini G., Putra A., Thompson D.J., Zhang X., Salim M.A. (2015), Use of a reciprocity technique to measure the radiation efficiency of a vibrating structure, Applied Acoustics, 89: 107–121, doi: 10.1016/j.apacoust.2014.09.013.
26. Stephanishen P.R. (1978), Radiated power and radiation loading of cylindrical surfaces with non-uniform velocity distribution, The Journal of the Acoustical Society of the America, 63(2): 328–338, doi: 10.1121/1.381743.
27. Sun Y., Yang T., Chen Y. (2018), Sound radiation modes of cylindrical surfaces and their application to vibro-acoustics analysis of cylindrical shells, Journal of Sound and Vibration, 424: 64–77, doi: 10.1016/ j.jsv.2018.03.004.
28. Szechenyi E. (1971), Modal densities and radiation efficiencies of unstiffened cylinders using statistical methods, Journal of Sound and Vibration, 19(1): 65– 81, doi: 10.1016/0022-460x(71)90423-8.
29. Wang C., Lai J.C.S. (2000), The sound radiation efficiency of finite length acoustically thick circular cylindrical shells under mechanical excitation. I: Theoretical analysis, Journal of Sound and Vibration, 232(2): 431–447, doi: 10.1006/jsvi.1999.2749.
30. Wang C., Lai J.C.S. (2001), The sound radiation efficiency of finite length circular cylindrical shells under mechanical excitation II: Limitations of the infinite length model, Journal of Sound and Vibration, 241(5): 825–838, doi: 10.1006/jsvi.2000.3338.
31. Yin X.W., Liu L.J., Hua H.X., Shen R.Y. (2009), Acoustic radiation from an infinite laminate composite cylindrical shells with doubly periodic rings, Journal of Vibration and Acoustics, 131(1): 011005–011009, doi: 10.1115/1.2980376.
32. Zhao X., Zhang B., Li Y. (2015), Vibration and acoustic radiation of an orthotropic composite cylindrical shell in a hygroscopic environment, Journal of Vibration and Control, 23(4): 673–692, doi: 10.1177/1077546315581943.
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Authors and Affiliations

S. Josephine Kelvina Florence
1
K. Renji
2

  1. Structures Group, U. R. Rao Satellite Centre, Bangalore, India-560017
  2. Advanced Technology Development Group, U. R. Rao Satellite Centre Bangalore, India-560017
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Abstract

In this study, the effects of replacing fine aggregate by granulated lead/zinc slag waste (GLZSW) on the thickness of concrete shields against X-ray radiation and on the compressive strength of concrete have been investigated. The fine aggregate was substituted by GLZSW in four percentages: 25%, 50%, 75%, and 100% (by weight). The first aim of the present study was to compare the thicknesses of concretes with GLZSW and control concrete using Lead Equivalent (LE). The second aim was to assess the effects of replacing fine aggregate by GLZSW on the compressive strength of concrete. Results of this study indicated that the compressive strength of mixed concretes increased significantly compared to the control upon replacing fine aggregate by GLZSW; the mixture containing 100% GLZSW had the greatest compressive strength. Further, the inclusion of GLZSW as a substitute for fine aggregate increased the radiation attenuation properties and consequently decreased the thickness of concrete shields in direct proportion to the mixing ratio of GLZSW. The results revealed that concrete mixes containing 100% GLZSW offered the greatest reduction in shield thickness. The study shows that there is a promising future for the use of GLZSW as substitute for fine aggregate in concrete used to shield against X-ray radiation.
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Authors and Affiliations

Mohamed Alwaeli
1

  1. Assoc. Prof., DSc., PhD., Eng., Mohamed Alwaeli, Silesian University of Technology, Faculty of Energy and Environmental Engineering, Konarskiego 18A, 44-100 Gliwice
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Abstract

The paper deals with a solution of radiation heat transfer problems in enclosures filled with nonparticipating medium using ray tracing on hierarchical ortho-Cartesian meshes. The idea behind the approach is that radiative heat transfer problems can be solved on much coarser grids than their counterparts from computational fluid dynamics (CFD). The resulting code is designed as an add-on to OpenFOAM, an open-source CFD program. Ortho-Cartesian mesh involving boundary elements is created based upon CFD mesh. Parametric non-uniform rational basis spline (NURBS) surfaces are used to define boundaries of the enclosure, allowing for dealing with domains of complex shapes. Algorithm for determining random, uniformly distributed locations of rays leaving NURBS surfaces is described. The paper presents results of test cases assuming gray diffusive walls. In the current version of the model the radiation is not absorbed within gases. However, the ultimate aim of the work is to upgrade the functionality of the model, to problems in absorbing, emitting and scattering medium projecting iteratively the results of radiative analysis on CFD mesh and CFD solution on radiative mesh.

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Authors and Affiliations

Paweł Kuczyński
Ryszard Białecki
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Abstract

Acoustic radiation sources are successfully applied to cleaning rooms from dust of fairly large particle sizes (ten micrometers and larger). The sedimentation of fine aerosols (particle diameter of 1-10 microns) is a more complicated challenge. The paper is devoted to the substantiation of the acoustic sedimentation method for such aerosols. On the basis of the mathematical model analysis for aerosol sedimentation by the acoustic field the mechanisms of this process have been determined and include the particle coagulation acceleration and radiation pressure effect. The experimental results of the acoustic sedimentation of a model aerosol (NaCl) are shown. The calculation results according to the mathematical model for coagulation and sedimentation, on the basis of the Smolukhovsky’s equation taking into account various mechanisms of aerosol sedimentation by sound depending on the particle sizes and sound intensity, are given. The necessity to use intensive sources of high-frequency sound has been confirmed, suggesting that these sources must be located above dust clouds.
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Authors and Affiliations

Olga Kudryashova
Alexandra Antonnikova
Natalya Korovina
Igor Akhmadeev
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Abstract

Most of sound sources are complex vibroacoustic objects consist of numerous elements. Some coupled vibrating plates of different shapes and sizes can be easily found in urban environments. The main aim of this study is to determine the sound radiation of coupled plates system of practical importance. The investigated vibroacoustic system consist of a thin circular plate coupled with a thick flat baffle with a circular hole. The circular plate has been mounted to the baffle’s hole using screws and two steel rings. The measurement setup was located inside a semi-anechoic chamber to assure the free field conditions. It was necessary to take into account the whole system surface to obtain the radiation efficiency based on the Hashimoto’s method. Such an approach can be troublesome and time-consuming. Therefore, the criterion has been proposed which allows the vibration velocity measurements and calculations to be performed only for the thin plate’s area. An alternative approach has been proposed based on the classical Rayleigh integral formula. Its advantage is a simpler implementation in a computer code. The obtained results have been compared with the theoretical results obtained for the elastically supported circular plate. A good agreement has been obtained at low frequencies.

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Authors and Affiliations

Wojciech P. Rdzanek
Krzysztof Szmela
Wojciech Żyłka

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