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Number of results: 53
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Abstract

Single Frequency Networks (SFN) of transmitters are currently used in television and digital broadcasting to effectively cover large areas using minimal spectral resources and using transmitters with much lower power than if the same area were covered using one transmitter. It is therefore a very ecological solution. In this way, much better reception conditions are obtained in large city areas, as the signal reaches the receiving antenna from different directions, reducing the risk of shading. However, in this type of network one should take into account the loss of signal caused by signal interference. Using the appropriate propagation model, it is possible, with appropriate assumptions, to check how the operation of the third transmitter affects the distribution and size of the deepest fades in relation to the network in which there are two transmitters.

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Authors and Affiliations

Ryszard J. Z Ziielinski
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Abstract

The research problem of the article refers to the question of the sense of using concrete prefabrication to create a new quality of architecture for single-family houses. Known and referenced projects from the past — from the period of early architectural Rationalism (Modernism and Functionalism) — seem appropriate to show, recall and update the idea of concrete prefabrication of single-family houses in the present day. This point of reference, having its source in the vision of the housing revolution from the beginning of the 20th century, can today be the subject of direct references and the search for further variants of rational patterns of modern prefabrication of single-family houses. The article is based on the most important items from the beginnings of concrete prefabrication technology, including Vers une architecture (1923) by Le Corbusier and articles and manuscripts by Walter Gropius following new concepts in German construction. Newer items include the Gilbert Herbert’s text that summarizes the heritage of Gropius’ prefabrication entitled The Dream of the Factory Made House by Walter Gropius and Konrad Wachsmann (1984).
The research method was the analysis of selected historical and contemporary houses built either in whole or in part in the precast concrete technology (a multiple-case study). The presentation of new examples shows the possibility of adapting the rational ideas and aesthetics of architecture from the early 20th century with the use of the latest concrete technologies. According to the author, the sense of concrete prefabrication in the construction of single-family houses is to return to the idea of ‘developed’ technology rationalization and Modernist architectural aesthetics. Although prefabrication is associated with the domain of economization, modularity, standardization and typification, thanks to advanced technologies, a prefabricated house in the 21st century can be a proof of the multitude of possible configurations.
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Authors and Affiliations

Marcin Charciarek
1
ORCID: ORCID
Jan Dziadek
2
ORCID: ORCID
Aleksandra Kubacka
2
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Architecture
  2. Doctoral School at Cracow University of Technology, Faculty of Architecture
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Abstract

Villa architecture after 1914 comprises a diverse and extensive group of buildings. The lack of a system of valuating them leads to their analyses being a time-consuming and complex process. Their justification can refer primarily to architectural and urban planning tendencies, including: the impact on the space of previously built estates, the assessment of the quality of their architecture in the landscape context and the continuity of design traditions, contemporary interventions associated with renovation work. The protection of villas from the interwar period, appears to be particularly important. Their cultural value and the quality of the landscape, that they co-create with their accompanying gardens is highly significant to the identity of the city.

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Authors and Affiliations

Katarzyna Łakomy
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Abstract

This paper presents the main dilemma of development of the Polish energy sector on the 20th anniversary of the first liberalization directive of the European Union, which created the energy market. The situation in the Polish energy sector based on fossil fuels, its transformation into lower emission one is closely connected to the process of restructuring and further development of the mining sector. On the other hand, we are witnessing the development of RES, household installations producing electricity with storage and the electrification of public transport. The investments in new, large scale fossil fuel fired power plants are very expensive and not economically proven when electricity prices are low. Until the new direction of investment in energy sector will be decided, the option of the lasting of the operating existing power units seems to be a good proposal. Is the thesis: “The energy security of Poland should be fully based on indigenous sources, generation and distribution assets, delivering electricity to end users. Ensuring competitive energy prices to the economy and households, the market should be fully open to producers and consumers, including chip electricity arising from the European single market” the right assumption for the Polish energy policy?

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Authors and Affiliations

Stanisław Tokarski
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Abstract

The article presents reviews of the European Union regulation on reporting formalities for ships entering the EU ports. It also analyses IMO regulation concerning that matter. Finally, the author exposes the differences between both legal systems and weaknesses of the solutions adopted. In the second part of the article the author discusses the Polish way of the reporting formalities system’s implementation. On the basis of a legal analysis as well as practice of the maritime authorities in Poland, the author finds that the Polish regulations seem to be exemplary.

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Authors and Affiliations

Justyna Nawrot
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Abstract

The corporate cost of capital is used by valuators to discount future flows of income from an entity in order to derive a present-day, forward-looking value of that entity. The cost of capital is therefore determined as the weighted cost of the various sources of funding, being typically equity, debt and preference instruments. The tricky and important part is estimating the cost of equity, which usually needs the application of finance models. The study on the texts on mineral valuation or mineral project evaluation demonstrates that the capital asset pricing model (CAPM) is a general model for estimating the cost of equity. However, according to shortfalls and problems relating to it a relatively similar and simpler model i.e. the single-index market model is proposed. The single index market model is an important tool in contemporary research in finance. Much of the importance of the model follows from its 'beta' parameter which, ideally, measures the sensitivity of returns on a security to changes in a market model. To estimate the cost of equity of the mining and cement companies listed in Tehran Stock Exchange (TSE) The single-index market model is selected because of the shortfalls and problems of the CAPM as well as the lack of commercial services for determining the market premium. The regression analysis as well as the statistical analysis is carried out using Excel spreadsheet. The statistic significance of the model is tested using t and F test statistics. The results showed that the independent variable (the rate of return on the market index) has a genuine effect on the dependent variable (the rate of return for the stock) and there is a statistically significant linear relationship between the two variables at significance level of 5%. Finally, the cost of equity formining and cement companies is estimated 25.0% and 31.0% respectively. Knowing the cost of equity, calculating the discount rate will not be very difficult.

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Authors and Affiliations

Mohsen Taheri
Mehdi Irannajad
Majid Ataee-Pour
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Abstract

A new double stator permanent magnet machine having two sets of alternating current (AC) windings in separate stators is proposed in this study. The proposed machine is appropriate for low-speed direct-drive applications. 2D- and 3D-finite element analysis (FEA) is adopted in the result predictions. The considered machine elements are: coil and phase flux linkage, coil and phase induced-electromotive force (EMF), copper loss, current density and torque characteristics. The analysis shows that the studied permanent magnet (PM) machine has better electromagnetic performance than its single-stator equivalent. Moreover, the proposed machine has potential for higher reliability if the separate stators are used independently. The effect of design parameters on open-circuit flux linkage and induced-electromotive force, as well as on the average electromagnetic torque of the proposed double stator machine is also presented. It is observed that for each of the investigated design variables, there is a need to select the optimal value in order to achieve the best average torque. The investigated design parameters are: the split ratio, magnet thickness, rotor radial thickness, inner stator tooth-width, rotor inner and outer iron-width/pitch ratio, and stator yoke size.
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Authors and Affiliations

Chukwuemeka Chijioke Awah
1
ORCID: ORCID

  1. Michael Okpara University of Agriculture Umudike, Nigeria
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Abstract

In order to realize constant current and constant voltage charging for batteries by inductively coupled power transfer (ICPT) technology, a single-switch CL/LCL circuit is designed. The single-switch CL/LCL circuit is composed of a CL/LCL compensation network and single-switch inverter. The proposed circuit is compared with the traditional constant current and constant voltage circuit in the structure. The operating process of the single-switch CL/LCL circuit and the principle to realize a zero-voltage switch (ZVS) are analysed in detail in this paper. The voltage gain and current gain of the circuit are cal- culated, which demonstrates that the circuit is able to suppress higher harmonics strongly. By using Fourier decomposition, the voltage on the primary-side compensation capaci- tor can be obtained. After constructing the equivalent mutual inductance model of the circuit, the formulas and parameters are deduced and calculated. Finally, an experiment platform is built to verify the proposed circuit can realize constant current and constant voltage.

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Authors and Affiliations

Guangzong Zhang
Chunfang Wang
Jianfen Zheng
Houji Li
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Abstract

River training structures; such as submerged groynes are low profile linear structures that are generally located on the outside bank to form groynes fields and prevent the erosion of stream banks by keeping a flow away from it. In the present research, the maximum scour depth was measured based on laboratory experiments where different shapes of submerged groynes (I-shape, L-shape, T-shape) were used as sort of countermeasures to investigate about most shapes that reduce the scour around them. The result of submerged groynes showed a clear decrease in scour depth ratio due to increasing sub-merged ratio and increase the scour hole geometry with increasing of flow intensity, and also Froude number. The maxi-mum scour hole in this research was observed at T-shape groyne and then followed by I-shape groyne and L-shape groyne. The maximum scour depth that cased by I-shape was more than L-shape by a percentage about 8.2%, and it was less than T-shape by a percentage about 16.4%.

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Authors and Affiliations

Budoor M. Rashak
Saleh I. Khassaf
ORCID: ORCID
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Abstract

The article presents the methodology for measuring verification of the phenomenon of fades in the DAB+ SFN. The verification is related to comparing the characteristics of the fades determined theoretically with the occurring fades in the real environment of a large city. The conditions favorable for the occurrence of fading are presented and by selecting the appropriate propagation analysis tool, the places where the occurrence of fading is most likely were selected. In these places an analysis of the characteristics of fades was carried out and the conditions for their verification were determined.
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Bibliography

[1] WorldDAB, „WorldDAB infographic (Q2 2019)”, https://www.worlddab.org/resources/infographic. (29 03 2020).
[2] S. Kubal, M. Kowal, P. Piotrowski, K. Staniec, “Optimal Transmission Technique for DAB+ Operating in the SFN Network”, in Springer Nature Switzerland, Theory and Applications of Dependable Computer Systems, Proceedings of the Fifteenth International Conference on Dependability of Computer Systems DepCoS-RELCOMEX, June 29 – July 3, 2020, Brunów, Poland.
[3] European Telecommunications Standards Institute, EN 300 401 V2.1.1 Draft ETSI EN 300 401 V2.1.1 Radio Broadcasting Systems; Digital Audio Broadcasting (DAB) to mobile, portable and fixed receivers, 2016.
[4] European Broadcasting Union, „TR 24 SFN Frequency planning and network implementation with regard to T-DAB and DVB-T,” Genewa, 2013.
[5] R. Zieliński, “Fade analysis in DAB+ SFN network in Wroclaw”, Proc. of the 2019 International Symposium on Electromagnetic Compatibility (EMC Europe 2019), Barcelona, Spain, September 2– 6, 2019, (978-1-7281-0594-9/19/$31.00 © 2019 IEEE).
[6] D. Plebs, J. Wout., P. Angueira, J.A. Arenas, L. Verloock, L. Martens,: “On the Methodology for Calculating SFN Gain in Digital Broadcast Systems”, IEEE Transactions on Broadcasting, Vol. 56, No. 3, September 2010, pp.331-339
[7] K. Staniec, S. Kubal, M. Kowal, P. Piotrowski,: “On the Influence of the Coding Rate and SFN Gain on DAB+ Coverage”, Advances in Intelligent Systems and Computing, 2020.
[8] P. Gilski, J. Stefanski, “Subjective and Objective Comparative Study of DAB+ Broadcast System”, Archives of Acoustics, Vol. 42, No. 1, pp. 3–11 (2017), by PAN – IPPT)
[9] S. Brachmański, M. Kin, “Assessment of speech quality in Digital Audio Broadcasting (DAB+) system”, AES 134th Convention, Rome, Italy, 2013.
[10] M. Kin, “Subjective evaluation of sound quality of musical recordings transmitted via DAB+ system", in Proc. 134th Audio Engineering Society Convention, Rome, Italy, 2013, pp. 1231{2366.
[11] P. Gilski., J. Stefanski, “Digital Audio Broadcasting or Webcasting: A Network Quality Perspective”, Journal of Telecommunications and Information Technology, 1, 9–15, 2016.
[12] P. Pocta, J.G. Beerends, “Subjective and Objective Assessment of Perceived Audio Quality of Current Digital Audio Broadcasting Systems and WebCasting Applications”, IEEE Transactions on Broadcasting, 61, 407–415, 2015.
[13] International Telecommunication Union, ITU-R BS.2214-3, “Planning parameters for terrestrial digital sound broadcasting systems in VHF bands”, 2019.
[14] European Broadcasting Union, TECH 3391, “Guidelines for DAB network planning”, Genewa, 2018.
[15] National Institut of Telecommunications, „LokalDAB,”. https://www.il-pib.pl/pl/projekty-krajowe/projekty-krajowe-ze-srodkow-na-nauke/projekt-localdab, (25 05 2020).
[16] Radio Polska, „MUX LokalDAB,”. http://radiopolska.pl/wykaz/mux/145. (2020 05 25).
[17] European Broadcasting Union, TR 016, “Benefits and Limitations of Single Frequency Networks (SFN) for DTT”, 2012.
[18] A. Tissen, A. Waal, F. Maier, “Evaluations and Measurements of a Single Frequency Network with DRM+”, European Wireless Conference, Poznan, 2012.
[19] R. Zieliński, “Conditions for obtaining correct DAB+ signal reception on a single frequency network” (in polish), Przegląd Telekomunikacyjny i Wiadomości Telekomunikacyjne, nr. 6, 2017, str. 509-512.
[20] R. Zieliński, “Analysis of depth of fades in a single frequency DAB+ network on the example of the network in Wroclaw” (in polish), Przegląd Telekomunikacyjny i Wiadomości Telekomunikacyjne, nr. 6, 2018, str. 320-325
[21] R. Zieliński, “Distribution of fade area in a SFN network on the example of the DAB+ network” (in polish), Przegląd Telekomunikacyjny i Wiadomości Telekomunikacyjne, nr. 8-9, 2018, str. 581-584.
[22] R. Zieliński, “Analysis of the phenomenon of fades in the SFN DAB+ network with three transmitters on the example of the network in Wroclaw” (in polish),. Przegląd Telekomunikacyjny i Wiadomości Telekomunikacyjne, nr. 6, 2019, str. 386-391.
[23] R. Zieliński, “Analysis and Comparision of the Fade Phenomenon in the SFN DAB+ Network With Two and Three Transmitters”, Intl Journal of Electronics and Telecommunications, 2020, Vol. 66, No. 1, str.. 85-92.
[24] International Telecommunication Union, Recommendation ITU-R P.1546-5 : “Method for point-to-area predictions for terrestrial services in the frequency range 30 MHz to 3 000 MHz”, 2013.
[25] I. Michalski, thesis, "Analysis of the distribution of e-m field strength and fades from the SFN DAB+ network in Wroclaw”, Wroclaw University of Science and Technology, 2020.
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Authors and Affiliations

Igor Michalski
1
ORCID: ORCID
Ryszard J. Zielinski
2
ORCID: ORCID

  1. National Institute of Telecommunications, Poland
  2. Wroclaw University ofScience and Technology, Poland
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Abstract

Blood samples from forty-six roe deer ( Capreolus capreolus) acquired during officially approved hunting in six hunting divisions throughout Poland were used to isolate the genomic DNA. All individuals were genotyped by MD_Bovine BeadChip (Illumina) for 46.750 Single Nucleotide Polymorphism (SNP) markers. SNPs of inappropriate clusters, with a marker call rate lower than 90% and with a minor allele frequency (MAF) lower than 0.01, located on sex chromosomes and mitochondrial DNA, were removed. Altogether, 21.033 SNP markers were included for further analysis. Observed and expected heterozygosity amounted to 0.098 and 0.119, respectively. Among 21.033 markers, a panel of 148 SNPs were selected for relationship analysis. They were unlinked and had a MAF higher than 0.2. This set of SNPs showed a probability of parentage exclusion of 1.29x10 -6 and 2.37x10 -19 for one, and two known parents, respectively. The probability of identity was estimated at 1.8x10 -40. The probabilities obtained in this study are sufficient for the monitoring and effective management of the genetic diversity of roe deer in Poland and is a cost-effective complementary tool for forensic applications.
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Bibliography

References:

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Haynes GD, Latch EK (2012) Identification of Novel Single Nucleotide Polymorphisms (SNPs) in Deer (Odocoileus spp.) Using the Bo-vineSNP50 BeadChip. PLoS One 7: e36536.
Heaton MP, Harhay GP, Bennett GL, Stone RT, Grosse WM, Casas E, Keele JW, Smith TP, Chitko-McKown CG, Laegreid WW (2002) Selection and use of SNP markers for animal identification and paternity analysis in U.S. beef cattle. Mamm Genome 13: 272-281.
Jamieson A, Taylor SC (1997) Comparison of three proba- bility formulae for parentage exclusion. Anim Genet 28: 397-400.
Kaltenbrunner M, Hochegger R, Cichna-Markl M (2018) Sika deer (Cervus nippon)-specific real-time PCR method to detect fraudulent label-ling of meat and meat products. Sci Rep 8: 7236.
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McClure MC, McCarthy J, Flynn P, McClure JC, Dair E, O’Connell DK, Kearney JF (2018) SNP Data Quality Control in a National Beef and Dairy Cattle System and Highly Accurate SNP Based parentage verification and Identification. Front Genet. 15: 84.
Miller JM, Poissant J, Kijas JW, Coltman DW (2011) International Sheep Genomics Consortium. A genome-wide set of SNPs detects popu-lation substructure and long range linkage disequilibrium in wild sheep. Mol Ecol Resour 11: 314-322
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Morf NV, Kopps AM, Nater A, Lendvay B, Vasilievic N, Webster LMI, Fautley RG, Ogden R, Kratzer A (2021) STRoe deer: A validated forensic STR profiling system for the European roe deer (Capreolus capreolus). Forensic Sci Int Anim Environ 1: 100023
Pertoldi C, Wójcik JM, Tokarska M, Kawałko A, Kristensen TN, Loeschcke V, Gregersen VR, Coltman D, Wilson GA, Randi E, Henryon M, Bendixen C (2010) Genome variability in European and American bison detected using BovineSNP50 BeadChip. Conserv Genet 11: 627-634.
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Werner FA, Durstewitz G, Habermann FA, Thaller G, Krämer W, Kollers S, Buitkamp J, Georges M, Brem G, Mosner J, Fries R (2004) Detection and characterization of SNPs useful for identity control and parentage testing in major European dairy breeds. Anim Genet 35: 44-9.
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Authors and Affiliations

K. Oleński
1
D. Zalewski
2
S. Kamiński
1

  1. University of Warmia and Mazury, Department of Animal Genetics, M. Oczapowskiego 5, 10-718 Olsztyn, Poland
  2. University of Warmia and Mazury, Department of Fur-bearing Animal Breeding and Game Management, M. Oczapowskiego 5, 10-718 Olsztyn, Poland
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Abstract

Single Image Super-Resolution (SISR) through sparse representation has received much attention in the past decade due to significant development in sparse coding algorithms. However, recovering high-frequency textures is a major bottleneck of existing SISR algorithms. Considering this, dictionary learning approaches are to be utilized to extract high-frequency textures which improve SISR performance significantly. In this paper, we have proposed the SISR algorithm through sparse representation which involves learning of Low Resolution (LR) and High Resolution (HR) dictionaries simultaneously from the training set. The idea of training coupled dictionaries preserves correlation between HR and LR patches to enhance the Super-resolved image. To demonstrate the effectiveness of the proposed algorithm, a visual comparison is made with popular SISR algorithms and also quantified through quality metrics. The proposed algorithm outperforms compared to existing SISR algorithms qualitatively and quantitatively as shown in experimental results. Furthermore, the performance of our algorithm is remarkable for a smaller training set which involves lesser computational complexity. Therefore, the proposed approach is proven to be superior based upon visual comparisons and quality metrics and have noticeable results at reduced computational complexity.

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Authors and Affiliations

Rutul Patel
Vishvjit Thakar
Rutvij Joshi
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Abstract

Following paper is focused on experimental and numerical studies of the behavior and energy absorption for both: quasi-static and dynamic axial crushing of thin-walled cylindrical tubes filled with foam. The experiments were conducted on single walled and double walled tubes. Unfilled profiles were compared with tubes filled with various density polyurethane foam. All experiments were done in order to possibility of the safety of the elements absorbing collision energy which can applied in car body. The dynamic nonlinear simulations were carried out by means of PAM-CRASH™ explicit code, which is dedicated calculation package to modelling of crush. Computational crushing force, plastic hinges locations and specimens post-crushed geometry found to be convergent with the real experiments results. Conducted experiments allowed to draw conclusion, that crashworthiness ability is directly proportional to foam density. The investigation of the experimental data revealed, that double walled tubes have greater energy absorbing ability. A proposed investigation enable to analyze and chosen of optimal parameters of these elements, which can use in automotive industry as an absorption energy components.

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Authors and Affiliations

P. Kaczyński
J. Karliński
M. Hawryluk
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Abstract

In this contribution, an overview over a numerical scheme for the crack modelling of spruce wood under tensile loading is given. A material model for biaxially stressed spruce wood with consideration of the effect of knots on the strength properties has been developed. A necessary feature of this material model is its ability to treat cracks by means of the so-called smeared crack concept. For this reason the consideration of a so-called characteristic length in the corresponding evolution laws of the strength values is required. The successful implementation in the material model is shown by means of various numerical examples.
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Authors and Affiliations

Herbert W. Mulllner
Christoph Kohlhauser
Martin Fleischmann
Josef Eberhardsteiner
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Abstract

The aim of this article is to present the ephemera related to Sandomierz — either by content or place of the publication — whose distinctive trait was the use of the word 'jednodniówka', or single issue, in the title, the subtitle or the contents. Chronologically, this survey ranges from 1918, the date of the first print of this kind to be published, to the last one (known to the au-thors) dated 2002 and does not cover publications in languages other than Polish. The source material gathered in accordance with these criteria comprises a total of 34 single issues, of which ten appeared in the pre-war period and twenty-four after World War II. Themati-cally, ten of them can be classified as political or concerned with social issues; eight are products of trade unions or other professional associations; twelve are aimed at the younger generation; and each of the remaining four has a focus of its own (i.e. military, historical, religious, literary-artistic). In this article all of the single issues are discussed both with regard to their in format (layout) and their content.
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Authors and Affiliations

Izabela Krasiński
1
ORCID: ORCID
Piotr Sławiński
2
ORCID: ORCID

  1. Katedra Dziennikarstwa i Komunikacji Społecznej, Uniwersytet Jana Kochanowskiego, ul. Uniwersytecka 17, PL 25-406 Kielce
  2. Archiwum Państwowe w Kielcach, Oddział w Sandomierzu, ul. Żydowska 4, PL 27-600 Sandomierz
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Abstract

Indonesia is widely known as a country with rich biodiversity. Medicinal plants that thrive in Indonesia are utilized as traditional medicine locally known as “jamu”. One of the islands famous for jamu production is Madura Island. As a well-known jamu producer, Madura Island are facing problems related to jamu production. Procurement of medicinal plants is not well controlled. There are no reports of spices procurement and production. When there is an increase in demand or sale of certain jamu, the stock of jamu is commonly inadequate/insufficient This may result in order cancellation. The solution to this problem is to create a production forecasting information system by using single exponential smoothing. The data used is a weekly report on the number of sales of 3 types of jamu from August to October 2024. Mean Absolute Percentage Error (MAPE) testing using an alpha value of 0.1 to 0.9 resulted in “high” accuracy and the forecasted values were close to the actual data values.
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Authors and Affiliations

Rika YUNITARINI
Muhamad Afif EFFINDI
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Abstract

With the developing technology and increasing construction, the importance of structural observations, which are of great significance in disaster management, has increased. Geodetic methods have been preferred in recent years due to their high accuracy and ease of use in Structural Health Monitoring (SHM) Surveys. In this study, harmonic oscillation tests have been carried out on a shake table to determine the usability of the Single Base and the Network Real-Time Kinematic (RTK) Global Navigation Satellite Systems (GNSS) method in SHM studies. It is aimed to determine the harmonic movements of different amplitudes and frequencies created by the shake table with 20 Hz multi-GNSS equipment. The amplitude and frequency values of the movements created using Fast Fourier Transform (FFT) and Time Series Analysis have been calculated. The precision of the analysis results has been determined by comparing the LVDT (Linear Variable Differential Transformer) data, which is the position sensor of the shake table, with the GNSS data. The advantages of the two RTK methods over each other have been determined using the calculated amplitude and frequency differences. As a result of all experiments, it has been determined that network and single base RTK GNSS methods effectively monitor structural behaviours and natural frequencies.
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Authors and Affiliations

Güldane Oku Topal
1
ORCID: ORCID
Burak Akpinar
1
ORCID: ORCID

  1. Yildiz Technical Universty, Istanbul, Turkey
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Abstract

This study presents the behavior of a single wall carbon nanotube (SWCNT)/water nanofluid for convective laminar flow inside a straight circular pipe heated by a constant heat flux. Five volume fractions of SWCNT were used to investigate their effect on the heat transfer coefficient, Nusselt number, temperature distribution and velocity field in comparison with pure water flow. One model for each property was tested to calculate the effective thermal conductivity, effective dynamic viscosity, and effective specific heat of the SWCNT/water mixture. The models were extracted from experimental data of a previous work. The outcomes indicate that the rheological behavior of SWCNT introduces a special effect on the SWCNT/water properties, which vary with SWCNT volume fraction. The results show an improvement in the heat transfer coefficient with increasing volume fraction of nanoparticles. The velocity of SWCNT/water nanofluid increased by adding SWCNT nanoparticles, and the maximum increase was registered at 0.05% SWCNT volume fraction. The mixture temperature is increased with the axial distance of the pipe but a reduction in temperature distribution is observed with the increasing SWCNT volume fraction, which reflects the effect of thermophysical properties of the mixture.
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Authors and Affiliations

Farqad Rasheed Saeed
1
Marwah A. Jasim
2
Natheer B. Mahmood
3
Zahraa M. Jaffar
4

  1. Ministry of Science Technology, Directorate of Materials Research, 55509 Al-Jadriya, Iraq
  2. University of Baghdad, College of Engineering, Al-Jadriya,10074 Al-Jadriya, Iraq
  3. Ministry of Education, General Directorate of Baghdad Education, Karkh 2, 10072 Al-Jadriya, Iraq
  4. Al Nahrain University, College of Science, 10072 Al-Jadriya, Iraq
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Abstract

The paper is a thermodynamics analysis of the removal of any inert gas from the tank using the vapors of any liquefied petroleum gas cargo (called cargo tank gassing-up operation). For this purpose, a thermodynamic model was created which considers two boundary cases of this process. The first is a ‘piston pushing’ of inert gas using liquefied petroleum gas vapour. The second case is complete mixing of both gases and removal the mixture from the tank to the atmosphere until desired concentration or amount of liquefied petroleum gas cargo in the tank is reached. Calculations make it possible to determine the amount of a gas used to complete the operation and its loss incurred as a result of total mixing of both gases.
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Authors and Affiliations

Agnieszka Wieczorek
1

  1. Gdynia Maritime University, Morska 81–87, 81-225 Gdynia, Poland
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Abstract

The work presents a numerical investigation for the convective heat transfer of nanofluids under a laminar flow inside a straight tube. Different models applied to investigate the improvement in convective heat transfer, and Nusselt number in comparison with the experimental data. The impact of temperature dependence, temperature independence, and Brownian motion, was studied through the used models. In addition, temperature distribution and velocity field discussed through the presented models. Various concentrations of nanoparticles are used to explore the results of each equation with more precision. It was shown that achieving the solution through specific models could provide better consistency between obtained results and experimental data than the others.
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Bibliography

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Authors and Affiliations

Farqad Rasheed Saeed
1
Marwah Abdulkareem Al-Dulaimi

  1. Ministry of Science and Technology, Directorate of Materials Research, 55509 Al-Jadriya, Iraq
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Abstract

This work investigates the effect of Reynolds number, nanoparticle volume ratio, nanoparticle size and entrance temperature on the rate of entropy generation in Al2O3 /H2O nanofluid flowing through a pipe in the turbulent regime. The Reynolds average Navier-Stokes and energy equations were solved using the standard k-ε turbulent model and the central composite method was used for the design of experiment. Based on the number of variables and levels, the condition of 30 runs was defined and 30 simulations were run. The result of the regression model obtained showed that all the input variables and some interaction between the variables are statistically significant to the entropy production. Furthermore, the sensitivity analysis result shows that the Reynolds number, the nanoparticle volume ratio and the entrance temperature have negative sensitivity while the nanoparticle size has positive sensitivity.

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Authors and Affiliations

O.G. Fadodun
B.A. Olokuntoye
A.O. Salau
Adebimpe A. Amosun
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Abstract

In this paper, investigation of the effect of Reynolds number, nanoparticle volume ratio, nanoparticle diameter and entrance temperature on the convective heat transfer and pressure drop of Al2O3/H2O nanofluid in turbulent flow through a straight pipe was carried out. The study employed a computational fluid dynamic approach using single-phase model and response surface methodology for the design of experiment. The Reynolds average Navier-Stokes equations and energy equation were solved using k-" turbulent model. The central composite design method was used for the response-surface-methodology. Based on the number of variables and levels, the condition of 30 runs was defined and 30 simulations were performed. New models to evaluate the mean Nusselt number and pressure drop were obtained. Also, the result showed that all the four input variables are statistically significant to the pressure drop while three out of them are significant to the Nusslet number. Furthermore, sensitivity analysis carried out showed that the Reynolds number and volume fraction have a positive sensitivity to both the mean Nusselt number, and pressure drop, while the entrance temperature has negative sensitivities to both.

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Authors and Affiliations

Olatomide G. Fadodun
Adebimpe A. Amosun
Ayodeji O. Salau
David O. Olaloye
Johnson A. Ogundeji
Francis I. Ibitoye
Fatai A. Balogun
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Abstract

The aim of the paper is to experimentally determine the scattering matrix S of an example reflective muffler of cylindrical geometry for Helmholtz number exceeding the plane wave propagation. Determining the scattering matrix of an acoustic systems is a new and increasingly used approach in the assessment of reduction of noise propagating inside duct-like elements of heating, ventilation and air conditioning systems (HVAC). The scattering matrix of an acoustic system provides all necessary information on the propagation of wave through it. In case of the analysed reflective silencer, considered as a two-port system, the noise reduction was determined by calculating the transmission loss parameter (TL) based on the scattering matrix (S). Measurements were carried out in two planes of the cross-section of pipes connected to the muffler.

The paper presents results of the scattering matrix evaluation for the wave composed of the plane wave (mode (0,0)) and the first radial mode (0,1), each of which was generated separately using the self-designed and constructed single-mode generator. The gain of proceeding measurements for single modes stems from the fact that theoretically, calculation of the S-matrix does not require, as will be presented in the paper, calculation of the measurement data inverse matrix. Moreover, if single mode sound fields are well determined, it ensures error minimization. The presented measurement results refer to an example of a duct like system with a reflective muffler for which the scattering matrix S was determined. The acoustic phenomena inside such a system can be scaled by the parameter ka.
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Authors and Affiliations

Łukasz Gorazd
1

  1. AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Kraków, Poland
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Abstract

Due to the nonlinear current-voltage (I-V) relationship of the photovoltaic (PV) module, building a precise mathematical model of the PV module is necessary for evaluating and optimizing the PV systems. This paper proposes a method of building PV parameter estimation models based on golden jackal optimization (GJO). GJO is a recently developed algorithm inspired by the idea of the hunting behavior of golden jackals. The explored and exploited searching strategies of GJO are built based on searching for prey as well as harassing and grabbing prey of golden jackals. The performance of GJO is considered on the commercial KC200GT module under various levels of irradiance and temperature. Its performance is compared to well-known particle swarm optimization (PSO), recent Henry gas solubility optimization (HGSO) and some previous methods. The obtained results show that GJO can estimate unknown PV parameters with high precision. Furthermore, GJO can also provide better efficiency than PSO and HGSO in terms of statistical results over several runs. Thus, GJO can be a reliable algorithm for the PV parameter estimation problem under different environmental conditions.
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Authors and Affiliations

Thuan Thanh Nguyen
1
ORCID: ORCID

  1. Faculty of Electrical Engineering Technology, Industrial University of Ho Chi Minh City, No. 12 Nguyen Van Bao, Ward 4, Go Vap District, Ho Chi Minh City, Vietnam

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