Latvian Journal of Physics and Technical Sciences最新文献_第3页

Synthesis of NaYF₄:Yb³⁺, Tm³⁺ Nanocrystals Via the Thermal Decomposition Method Using Refined Sunflower Oil 用精制葵花籽油热分解法制备NaYF4:Yb3+， Tm3+纳米晶

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0028

L. Smelkovs, V. Viksna, J. Teterovskis, J. Grube

{"title":"Synthesis of NaYF4:Yb3+, Tm3+ Nanocrystals Via the Thermal Decomposition Method Using Refined Sunflower Oil","authors":"L. Smelkovs, V. Viksna, J. Teterovskis, J. Grube","doi":"10.2478/lpts-2023-0028","DOIUrl":"https://doi.org/10.2478/lpts-2023-0028","url":null,"abstract":"Abstract In recent years, up-conversion luminescence nanoparticles have attracted significant attention from researchers in fields such as analytical chemistry (for example qualitative and quantitative analysis of metal and non-metal ions) and biomedicine (cancer imaging, drug delivery, treatment, etc.) due to their high rate of emission efficiency, easy surface functionalization, great chemical and thermal and photostability and other favorable properties. NaYF 4 in particular has attracted interest of researchers as a host material due to its low phonon energy, thus increasing the efficiency of emission. In this study, the synthesis of NaYF 4 :Yb 3+ ,Tm 3+ nanocrystals using the hydrothermal method was successfully carried out. Refined sunflower oil containing oleic acid was used as a solvent instead of analytical grade oleic acid and octadecene-1, reducing the cost of the synthesis. Using semi-quantitative XRD measurement analysis, it was determined that 25.3 % hexagonal β-NaYF 4 :Yb 3+ ,Tm 3+ as well as 23.8 % cubic α-NaYF 4 nanocrystal crystalline phases were found in the synthesized sample. The sample showed mainly luminescent characteristics typical of hexagonal NaYF 4 :Yb 3+ ,Tm 3+ lattice nanoparticles.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135195606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Blending Hydrogen With Natural Gas/Biomethane and Transportation in Existing Gas Networks 将氢与天然气/生物甲烷混合以及在现有天然气网络中的运输

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0030

L. Zemite, L. Jansons, N. Zeltins, S. Lappuke, I. Bode

{"title":"Blending Hydrogen With Natural Gas/Biomethane and Transportation in Existing Gas Networks","authors":"L. Zemite, L. Jansons, N. Zeltins, S. Lappuke, I. Bode","doi":"10.2478/lpts-2023-0030","DOIUrl":"https://doi.org/10.2478/lpts-2023-0030","url":null,"abstract":"Abstract The existing European Union (EU) natural gas network provides large capacity to integrate renewable (RGs) and low-carbon gases. Today, hydrogen contributes only a few percent to Europe’s energy consumption and is almost exclusively produced from fossil fuels and used in the industry. Nevertheless, hydrogen has a significant role to play in emission reduction in hard-to-decarbonize sectors, in particular, as a fuel in transport applications and as a fuel or feedstock in certain industrial processes (steel, refining or chemical industries, the production of “green fertilizers”). Carbon dioxide (CO 2 ) in reaction with hydrogen can also be further processed into synthetic fuels, such as synthetic kerosene in aviation. In addition, hydrogen brings other environmental co-benefits when used as fuel, such as the lack of air pollutant emissions. However, in transitional phase from fossil to RG, namely, renewable or green hydrogen, natural gas/biomethane and hydrogen blends, are needed to gradually replace natural in existing gas transmission and distribution networks. The gas networks are believed to be able to use natural gas/biomethane and hydrogen blends with 5–20 % of hydrogen by volume. Most systems and applications are able to handle it without a need for major infrastructure upgrades or end-use appliance retrofits or replacements. The promotion of hydrogen network such as European Hydrogen backbone (EHB) is gaining momentum in Europe. To decarbonize the natural gas grids, the threshold of hydrogen in the existing grid systems must be increased, which can be done by means of wider natural gas/biomethane and hydrogen blending and simultaneous transportation in currently operational gas networks.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":"221 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135195619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The Design and Performance of Internally Cooled Cutting Tools for Turning: A Literature Review 车削内冷刀具的设计与性能:文献综述

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0032

A. Korenkovs, E. Gerins, A. Kromanis

引用次数: 0

Application of Calcium Aluminate Doped with Mn and Cr in Optical Thermometry 掺锰、铬铝酸钙在光学测温中的应用

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0027

U. Rogulis, A. Fedotovs, P. Rodionovs, M. Kemere, A. Antuzevics, A. Sarakovskis, K. Alps, V. Kiseleva

引用次数: 0

The Role of Decentralized Electrode Boiler in Ancillary Services and District Heating: a Feasibility Assessment 分散电极锅炉在辅助服务和区域供热中的作用:可行性评估

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0029

K. Gicevskis, O. Linkevics

引用次数: 0

Acoustic Emission Method as a Means of Quality Control in Multilayer Welding of Thick-Walled Welded Joints 声发射法作为厚壁焊接接头多层焊接质量控制手段

IF 0.6

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0023

K. Carjova, M. Banov, L. Vinogradov, S. Kravchenko, G. Strautmanis

引用次数: 0

R&D of a Hydraulic Hydrogen Compression System for Refuelling Stations 加氢站液压氢气压缩系统的研制

IF 0.6

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0022

V. Bezrukovs, V. Bezrukovs, M. Konuhova, D. Bezrukovs, I. Kaldre, A. Berzins

{"title":"R&D of a Hydraulic Hydrogen Compression System for Refuelling Stations","authors":"V. Bezrukovs, V. Bezrukovs, M. Konuhova, D. Bezrukovs, I. Kaldre, A. Berzins","doi":"10.2478/lpts-2023-0022","DOIUrl":"https://doi.org/10.2478/lpts-2023-0022","url":null,"abstract":"Abstract The article presents a hydraulic hydrogen compression solution designed to serve as a booster compressor. It can be adapted to changing parameters of the inlet pressure of hydrogen and allows stabilising the hydrogen accumulation process in the high-pressure storage. The main results of this study were obtained using a numerical model developed to explore the thermodynamic processes that occur during the hydraulic compression of hydrogen. The modelling was carried out using COMSOL Multiphysics® 6.0 software with the CFD and heat transfer modules. The compression chamber in the form of a cylinder with a volume of 1.14 l and wall thickness of 5 mm was used in the computational model. The aim of these simulations was to investigate the temperature change limits of hydrogen, cylinder walls and working fluid, as well as to estimate the actual value of pressure inside the cylinder. The considered process of pressure increase in the cylinder chamber was modelled as a continuous change of volume filled with working fluid with discrete time step of 0.01 s, taking into account the increase of temperature inside the cylinder. The derived modelling results for different durations of compression stroke ts from 0.5 to 20.0 s were presented. The curves of energy consumption and temperature rise during the compression process were calculated for initial hydrogen pressures P1 = 3.0, 10.0, 15.0 and 20.0 MPa and compression ratio Kc = 5.0. The results of simulation of thermodynamic processes and their analysis allowed estimating energy consumption in the system of hydraulic compression and determining conditions which would lead to the increase in efficiency of hydrogen compression operation systems under consideration.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":"60 1","pages":"21 - 39"},"PeriodicalIF":0.6,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43559501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Influence of the Thermal Effect on the Stress-Strain State of the Soil 热效应对土壤应力-应变状态的影响

IF 0.6

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0024

N. Remez, A. Dychko, A. Kraychuk, S. Kraychuk, N. Ostapchuk

引用次数: 0

Adaptive Fault Locator for High-Voltage Transmission Lines Based on the Estimation of Power System Model Parameters 基于电力系统模型参数估计的高压输电线路自适应故障定位

IF 0.6

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0021

I. Zālītis, A. Dolgicers, J. Kozadajevs, J. Berkolds

{"title":"Adaptive Fault Locator for High-Voltage Transmission Lines Based on the Estimation of Power System Model Parameters","authors":"I. Zālītis, A. Dolgicers, J. Kozadajevs, J. Berkolds","doi":"10.2478/lpts-2023-0021","DOIUrl":"https://doi.org/10.2478/lpts-2023-0021","url":null,"abstract":"Abstract This paper presents an adaptive transmission line fault location method, which incorporates fault location devices at both line ends and utilises data import from a supervisory control and data acquisition system without strictly requiring data synchronisation. The developed method aims at achieving a higher degree of robustness, adaptiveness and accuracy. The adaptiveness is achieved by dynamic updating of mathematical models used on the basis of network-wide information, such as data on the state of circuit-breakers and apparent power at load and generation nodes. The robustness and accuracy are enhanced by incorporating two stages of identification of model parameters with the goal of reducing the decision variable space for the stage identifying fault parameters. Furthermore, in addition to utilisation of all measurements available at a particular substation, the developed method partially employs the measurements from the other end of the line by means of result cross-checks, but does not require a full data set, unlike deterministic-model-based methods. An optimisation-based approach, redundancy on the basis of extended measurement set, and cross-checks reduce the risk of fault location errors due to measurement errors or “voids” in the data available. Testing of the developed method demonstrates its accuracy and robustness in a wide range of pre-fault and fault regime scenarios, even when considering various pre-fault contingencies.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":"60 1","pages":"3 - 20"},"PeriodicalIF":0.6,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47711750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cancer-Causing and Non-Cancer-Causing Assessment of Uranium in Ground Water Samples of Kanchipuram District, Tamilnadu, India 印度泰米尔纳德邦坎奇普兰地区地下水样本中铀的致癌性和非致癌性评估

IF 0.6

Latvian Journal of Physics and Technical Sciences Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0026

M. Hamideen, A. Chandrasekaran, M. A. Neelakantan

{"title":"Cancer-Causing and Non-Cancer-Causing Assessment of Uranium in Ground Water Samples of Kanchipuram District, Tamilnadu, India","authors":"M. Hamideen, A. Chandrasekaran, M. A. Neelakantan","doi":"10.2478/lpts-2023-0026","DOIUrl":"https://doi.org/10.2478/lpts-2023-0026","url":null,"abstract":"Abstract Uranium is characteristic lithospheric component and is found nearly in all kinds of soils and waters; in any case, its quantity changes from water-to-water contingent on their cause. Subsequently, in the current investigation, the concentration of uranium in groundwater tests was estimated utilizing LED fluorimeter and the related health hazards appraisal was checked. The concentration of uranium ranges from 0.5 to 10.7 μg L−1 with average value of 2.76 μg L−1. The excess cancer hazard was seen in the scope of 1.416×10−6 – 30.309×10−6 with an average of 7.804 ×10−6. This mean estimation of the excess cancer risk in the Kanchipuram locale is less than the greatest adequate degree of l.67 × 10−4 as per AERB (2004). Consequently, there is no hurtful impact to the neighbourhood individuals who are devouring the water in the examination zone. The average cancer mortality and grimness chances were determined to show that the probability of cancer-causing chances related to water test and significant health was evaluated utilizing hazard quotient from chemical harmfulness of uranium. The values watched for hazard quotient in all areas in the examination are beneath the edge estimation of 1, as recommended by USEPA. This shows that there are no unsafe impacts on the nearby individuals in the investigation zone.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":"60 1","pages":"77 - 84"},"PeriodicalIF":0.6,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44956014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0