The Journal of Institute of Physical Energetics

Latvian Journal of Physics and Technical Sciences

Latvian Jnl Phys.Tech.Sci.ONL

<abstract>
<title style='display:none'>Abstract</title>
The paper provides simulation results for SUP (Stand Up Paddle) board appendage resistance. Additional propulsion is added to the SUP board. It is equipped with a waterjet. The waterjet is attached to the board rudder. This increases the drag coefficient for rudder five times. To reduce the drag variable, design options for the waterjet duct were proposed. The simulation tests were performed using SolidWorks Flow software using two types of simulations, namely, the pressure on the body and the flow around the body. The objective was to streamline the bluff duct of the waterjet and thus to create the appendage design with minimum drag force from fluid flow and possibly greater Inlet Velocity Ratio. Calculations showed that rounding-off the edges of waterjet duct resulted in 35 % of drag coefficient reduction, while further streamlining reduced it by additional 10 %.
</abstract>

Abstract

Laboratory of Experimental Mechanics of Materials

Keywords

<article-title>Modelling of Drag Force Reduction for a Waterjet Propulsion System</article-title>

Modelling of Drag Force Reduction for a Waterjet Propulsion System

{"article-title":"Modelling of Drag Force Reduction for a Waterjet Propulsion System"}

<abstract>
<title style='display:none'>Abstract</title>
To increase the sensitivity and efficiency of a gas sensor, nanostructured ZnO and Co3O4 layers were obtained by hydrothermal synthesis directly on the electrode surface, eliminating the use of binders. Scanning electron microscope images showed that the resulting nanostructured coatings were characterised by good adhesion to the surface and high porosity, which opened up the possibility of their further use in the process of developing a gas sensor. The efficiency of the obtained nanostructured coatings and their sensitivity at room temperature to various concentrations of CO2 were determined. The resistance curves of the samples were obtained as a function of gas concentration in the chamber, for Co3O4 and ZnO nanostructures.
</abstract>

<article-title>Metal Oxide Nanostructure-Based Gas Sensor for Carbon Dioxide Detection</article-title>

Metal Oxide Nanostructure-Based Gas Sensor for Carbon Dioxide Detection

{"article-title":"Metal Oxide Nanostructure-Based Gas Sensor for Carbon Dioxide Detection"}

<abstract>
<title style='display:none'>Abstract</title>
In this paper, calculations of 3D parameter <italic>Vm</italic> (material volume) of surfaces with irregular roughness and comparison with experimental data were performed, with further application of this parameter in calculations of wear intensity. First, using Mountains Map software for profilometric measurements, 3D roughness processing and determination of material volume <italic>Vm</italic> at specific relative levels γ were performed. The next step was an additional analysis of the distribution of surface ordinates using a theoretical and experimental Laplace function. The given check confirmed that for mostly surfaces with irregular roughness the ordinate distribution corresponds to the normal Gaussian distribution law, but in cases when the asymmetry of the ordinate distribution function goes outside the permissible limits (|∆<italic>Ssk</italic>|&gt; 10%), errors&gt; 10 % occur. On this basis, the mathematical formula of the material volume <italic>Vm</italic> was derived, and the obtained calculations were compared with the measured values. The results showed that the calculated values of the parameter <italic>Vm</italic> were very close to the experimental data (|∆<italic>Vm|</italic>&lt;10 %), while at the relative level γ=+3, errors occurred that was related to the deviation from the normal distribution law. It was concluded that the given parameter could be used in the calculations of linear wear intensity, knowing the relative level γ.
</abstract>

<article-title>Application of 3D Roughness Parameters for Wear Intensity Calculations</article-title>

Application of 3D Roughness Parameters for Wear Intensity Calculations

{"article-title":"Application of 3D Roughness Parameters for Wear Intensity Calculations"}

<abstract>
<title style='display:none'>Abstract</title>
The study offers a new method of collection and processing of meteorological data from the meteorological service based on observations and correction of numerical weather forecast errors using a new prediction algorithm. This algorithm vastly increases the accuracy of the short-term forecast of outdoor air temperature, which is subject to uncertainty due to the stochastic nature of atmospheric processes. Processing of temperature data using Kalman filter provides the decrease in predicted temperature errors. The main setup methods of Kalman filter have been examined. The article also describes the implementation of accuracy improving algorithm of predicted temperature using Python.
</abstract>

Department of Transport Electronics and Telematics, Faculty of Electronics and Telecommunications

<article-title>Forecasting Algorithm Based on Temperature Error Prediction Using Kalman Filter for Management System Development</article-title>

Forecasting Algorithm Based on Temperature Error Prediction Using Kalman Filter for Management System Development

<abstract>
<title style='display:none'>Abstract</title>
An effective and accurate methodology is developed to create an inverse surrogate model for the mass reduction analysis of the rod in the rod bundle inserted in the crossflow. The performance of two surrogate modelling approaches has been evaluated. These models are the Response Surface Method and Legendre polynomial approximations. The relationship between dominant frequencies, support stiffness and rod mass derived from Computational Fluid Dynamics simulations is used as input data for approximations. The selection of sample points is implemented with a new type of orthogonal design. The results have shown that the proposed methodology can reliably replace the finite volume model and drastically reduce computational time.
</abstract>

<article-title>Damage Detection of the Rod in the Crossflow Using Surrogate-Based Modelling</article-title>

Damage Detection of the Rod in the Crossflow Using Surrogate-Based Modelling

{"article-title":"Damage Detection of the Rod in the Crossflow Using Surrogate-Based Modelling"}

<abstract>
<title style='display:none'>Abstract</title>
In this paper, a kinematic analysis of Theo Jansen’s stepping mechanism has been carried out and an algorithm for finding the output link trajectory from the given dimensions of the stepping mechanism elements, implemented by Mathcad program, has been developed. It is possible to output characterising parameters of all intermediate links with any number of intermediate links of a step cycle of the mechanism. The dimensions of the mechanism elements have been selected so that they provide the optimal smooth trajectory of the stepping point, minimising the mechanism oscillations in the vertical plane. A comparison of the trajectories of the foot in this study with the classical trajectory of Theo Jansen and the trajectory from article [7] has been provided. A minimum swing of the oscillation of the centre of mechanism masses in the vertical plane has been selected as an optimality criterion, combined with the maximum smoothness of the trajectory, provided that maximization of the step height is not required.
</abstract>

<article-title>Research of Kinematic Stepping Mechanism</article-title>

{"article-title":"Research of Kinematic Stepping Mechanism"}

Latvian Journal of Physics and Technical Sciences is covered by the following services: <ul> <li> Astrophysics Data System (ADS) </li> <li> Baidu Scholar </li> <li> Cabell's Whitelist </li> <li> Chemical Abstracts Service (CAS) - CAplus </li> <li> Chemical Abstracts Service (CAS) - SciFinder </li> <li> CNKI Scholar (China National Knowledge Infrastructure) </li> <li> CNPIEC - cnpLINKer </li> <li> Dimensions </li> <li> DOAJ (Directory of Open Access Journals) </li> <li> EBSCO </li> <li> Engineering Village </li> <li> ExLibris </li> <li> Genamics JournalSeek </li> <li> Google Scholar </li> <li> Inspec </li> <li> Japan Science and Technology Agency (JST) </li> <li> J-Gate </li> <li> JournalGuide </li> <li> JournalTOCs </li> <li> KESLI-NDSL (Korean National Discovery for Science Leaders) </li> <li> MyScienceWork </li> <li> Naver Academic </li> <li> Naviga (Softweco) </li> <li> ProQuest </li> <li> Publons </li> <li> QOAM (Quality Open Access Market) </li> <li> ReadCube </li> <li> Reaxys </li> <li> SCImago (SJR) </li> <li> SCOPUS </li> <li> Semantic Scholar </li> <li> Sherpa/RoMEO </li> <li> TDNet </li> <li> TEMA Technik und Management </li> <li> Ulrich's Periodicals Directory/ulrichsweb </li> <li> WanFang Data </li> <li> Web of Science - Emerging Sources Citation Index </li> <li> WorldCat (OCLC) </li> <li> X-MOL </li> </ul>

Latvian Journal of Physics and Technical Sciences ist in den folgenden Services indiziert: <ul> <li> Astrophysics Data System (ADS) </li> <li> Baidu Scholar </li> <li> Cabell's Whitelist </li> <li> Chemical Abstracts Service (CAS) - CAplus </li> <li> Chemical Abstracts Service (CAS) - SciFinder </li> <li> CNKI Scholar (China National Knowledge Infrastructure) </li> <li> CNPIEC - cnpLINKer </li> <li> Dimensions </li> <li> DOAJ (Directory of Open Access Journals) </li> <li> EBSCO </li> <li> Engineering Village </li> <li> ExLibris </li> <li> Genamics JournalSeek </li> <li> Google Scholar </li> <li> Inspec </li> <li> Japan Science and Technology Agency (JST) </li> <li> J-Gate </li> <li> JournalGuide </li> <li> JournalTOCs </li> <li> KESLI-NDSL (Korean National Discovery for Science Leaders) </li> <li> MyScienceWork </li> <li> Naver Academic </li> <li> Naviga (Softweco) </li> <li> ProQuest </li> <li> Publons </li> <li> QOAM (Quality Open Access Market) </li> <li> ReadCube </li> <li> Reaxys </li> <li> SCImago (SJR) </li> <li> SCOPUS </li> <li> Semantic Scholar </li> <li> Sherpa/RoMEO </li> <li> TDNet </li> <li> TEMA Technik und Management </li> <li> Ulrich's Periodicals Directory/ulrichsweb </li> <li> WanFang Data </li> <li> Web of Science - Emerging Sources Citation Index </li> <li> WorldCat (OCLC) </li> <li> X-MOL </li> </ul>

Editor-in-Chief Namejs Zeltins, Institute of Physical Energetics, Latvia Deputy Editor-in-Chief Andris Sternbergs, Institute of Solid State Physics University of Latvia Deputy/Managing Editor Leo Jansons, Institute of Physical Energetics, Latvia Editors Energy and Power John Melngailis, University of Maryland, USA Timo Jääskeläinen, University of Joensuu, Finland Anna Mutule, Institute of Physical Energetics, Latvia Gaidis Klāvs, Institute of Physical Energetics, Latvia Āris Žīgurs, Latvia Lidia Gawlik, Polish Academy of Sciences, Poland Māris Balodis, JSC "Latvenergo", Latvia Physical Sciences Andrejs Siliņš, Institute of Solid State Physics, Latvia Andris Ozols, Riga Technical University, Latvia Kurt Schwartz, Research Reactor to Darmstadt, Germany Mārtiņš Rutkis, Institute of Solid State Physics, Latvia Jānis Kalnačs, Institute of Physical Energetics, Latvia Anatolijs Šarakovskis, Institute of Solid State Physics, Latvia Aleksejs Kuzmins Institute of Solid State Physics, Latvia Ēriks Birks, Institute of Solid State Physics, Latvia Language Editor Oksana Ivanova, Institute of Physical Energetics, Latvia Technical Editor Igor Begichev, Institute of Physical Energetics, Latvia Contact Krivu street, 11 Riga, LV-1006 LATVIA tel: +371 67551732 fax: +371 67550839 <a href="mailto:leo@lza.lv">leo@lza.lv</a> Publisher De Gruyter Poland Bogumiła Zuga 32A Str. 01-811 Warsaw, Poland T: +48 22 701 50 15

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Latvian Journal of Physics and Technical Sciences (Latvijas Fizikas un Tehnisko Zinātņu Žurnāls) publishes experimental and theoretical papers containing results not published previously and review articles. Its scope includes Energy and Power, Physical Sciences, Physics and Applied Physics in Engineering, Environmental Biotechnology. <DIV align=left> Why subscribe and read <UL> <LI>premier source of high quality research from CEE countries and from all over the world; </LI> <LI>fast growing journal published in EU; articles authored by researchers from all over the world, who appreciate our thorough and constructive peer review. </LI></UL> Why submit <UL> <LI>thorough and constructive peer review; publicity for authors; </LI> <LI>language-correction services for authors from non-English speaking regions. </LI></UL> Archiving Sciendo archives the contents of this journal in <A href="https://www.portico.org/">Portico</A> - digital long-term preservation service of scholarly books, journals and collections. Plagiarism Policy The editorial board is participating in a growing community of <A href="https://www.crossref.org/services/similarity-check/">Similarity Check System's</A> users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. </DIV>

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Latvian Journal of Physics and Technical Sciences

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Volumen 58 (2021): Heft 5 (October 2021)

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