Latvian Journal of Physics and Technical Sciences最新文献_第2页

Energy Performance of Higher Education Institutions Buildings Operating During Quarantine Restrictions and/or Martial Law in Ukraine 乌克兰高等教育机构建筑在检疫限制和/或戒严期间的能效表现

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-03-30 DOI: 10.2478/lpts-2024-0012

V. Deshko, I. Bilous, T. Boiko, O. Shevchenko, A. Borodinecs, J. Zemitis

{"title":"Energy Performance of Higher Education Institutions Buildings Operating During Quarantine Restrictions and/or Martial Law in Ukraine","authors":"V. Deshko, I. Bilous, T. Boiko, O. Shevchenko, A. Borodinecs, J. Zemitis","doi":"10.2478/lpts-2024-0012","DOIUrl":"https://doi.org/10.2478/lpts-2024-0012","url":null,"abstract":"\u0000 During the pandemic and periods of martial law, educational institutions in Ukraine implemented various forms of organising the educational process, combining in-person and remote classes. As a result, there has been a decrease in the level of use of building premises. The analysis of the characteristics of energy consumption in these conditions requires additional attention. In this study, a dynamic energy model of the building was created using the educational building of Igor Sikorsky Kyiv Polytechnic Institute as an example. Energy consumption for heating needs was determined for normal operating conditions and quarantine conditions in Ukraine (only a specific part of the premises is being operated, ensuring that the standard temperature value is maintained while people are present). Based on the results of the study, the features of the energy consumption of the building during quarantine/martial law restrictions, subject to the partial use of the building, were analysed, and the main disadvantages of such a mode were identified. For the educational building of the university, the total energy consumption for heating needs depends on the number of rooms that are actively used, and the modes of regulation of heating and ventilation; the consumption can decrease depending on the chosen scenario by 61 %, 56 %, and 34 % in quarantine mode. The findings indicate that the efficiency of regulation modes can decrease by more than four times when compared to normal mode due to internal heat exchange with unoccupied rooms.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140364205","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

Injection of Renewables Gases Into the Existing Gas Distribution Grids and Employment of Reverse Gas Flow Technique 将可再生能源气体注入现有配气网并采用气体逆向流动技术

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-03-30 DOI: 10.2478/lpts-2024-0013

L. Jansons, J. Silina, I. Bode, L. Zemite, N. Zeltiņš, K. Palkova

{"title":"Injection of Renewables Gases Into the Existing Gas Distribution Grids and Employment of Reverse Gas Flow Technique","authors":"L. Jansons, J. Silina, I. Bode, L. Zemite, N. Zeltiņš, K. Palkova","doi":"10.2478/lpts-2024-0013","DOIUrl":"https://doi.org/10.2478/lpts-2024-0013","url":null,"abstract":"\u0000 Sustainability and longevity of existing gas grid exploitation perspective are closely related to two fundamental issues: their ability to adopt to changing gas fuel production and supply landscape in the context of methane-based fuels, mostly, biomethane, and in the context of non-methane-based fuels, mostly, low carbon and green hydrogen. Renewable gases and their ever-growing presence in gas transmission and distribution systems open up a discussion about the necessity to revise and restructure the original – vertically integrated layout of the gas systems, where gas supply is only technically possible from the transmission system towards distribution one, and not vice versa. Development of numerous decentralized biomethane production facilities connected to the gas distribution system causes a necessity to ensure the possibility to pass biomethane surplus of a certain production area into the gas transmission grid, thus avoiding necessity to install biomethane storage capacities locally and granting other regions an opportunity to use said surplus in their gas consumption immediately. The article addresses biomethane production trends and actions taken towards the development of reverse flow gas stations in France – one of biggest biomethane producers in Europe to date, and opportunities and challenges, which this technique might face in smaller and less active renewable gas markets as the one of Latvia.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140363803","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

Analysis of the Energy Consumption for Heating in Schools 学校供暖能耗分析

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-03-30 DOI: 10.2478/lpts-2024-0014

M. Sinakovics, A. Zajacs, A. Palcikovskis, V. Jacnevs

引用次数: 0

Enhanced-Reach Polarization Optical Time-Domain Reflectometry Technique for Fibre Optical Infrastructure Monitoring 用于光纤基础设施监测的增强型偏振光时域反射测量技术

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-03-30 DOI: 10.2478/lpts-2024-0011

J. Braunfelds, S. Spolitis, D. Cirjulina, A. Ostrovskis, J. Porins, L. Gegere, A. Supe

引用次数: 0

Red Persistent Luminescence and Trap Properties of Mg2SiO4: Mn2+, M3+ (M3+ = B3+; Al3+; Ga3+; In3+) Material Mg2SiO4: Mn2+, M3+ (M3+ = B3+; Al3+; Ga3+; In3+) 材料的红色持久发光和阱特性

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-03-30 DOI: 10.2478/lpts-2024-0008

G. Doke

{"title":"Red Persistent Luminescence and Trap Properties of Mg2SiO4: Mn2+, M3+ (M3+ = B3+; Al3+; Ga3+; In3+) Material","authors":"G. Doke","doi":"10.2478/lpts-2024-0008","DOIUrl":"https://doi.org/10.2478/lpts-2024-0008","url":null,"abstract":"\u0000 Persistent luminescence (PersL), also called long-lasting phosphorescence or simply afterglow, is a luminescence characterised by the emission of radiation from a few seconds to several days after the excitation source has been switched off. Over the past two decades, research on PersL materials, both in fundamental and applied physics, has developed rapidly; however, the explanation for the physical processes that cause afterglow still needs to be clarified. Today, PersL materials are used mainly for luminescent paints, safety signs and decorations. At the same time, research into using such materials in medicine, information storage, anti-counterfeiting technology, etc., is underway.\u0000 Currently, information on the long persistent luminescence materials with emission in the blue and green spectral range is widely available. In contrast, the number of publications on the afterglow in the red and near-infrared spectral range is considerably lower.\u0000 Within the framework of this research, Mg2SiO4: Mn2+; M3+ (M3+ = B3+; Al3+; Ga3+; In3+) materials were synthesised using solid state reaction synthesis. When excited with X-rays, the materials exhibited a broad Mn2+ PersL band with two maxima at approximately 625 nm and 730 nm. After cessation of irradiation, an afterglow of at least 6 hours could be observed.\u0000 The research focuses on the trap properties of the materials. It was concluded that at least three discrete trap levels with activation energies approximately between 0.4–1.6 eV were present in the samples. Additionally, co-doping with Al3+; Ga3+; In3+ ions improved PersL longevity of the Mg2SiO4: Mn2+ material.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140363343","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 First Application of Laser-Induced Breakdown Spectroscopy: A Fast-Analytical Technique in Targeted Search for Elements in Geological Samples from Deep Boreholes in Latvia 激光诱导击穿光谱的首次应用：拉脱维亚深孔地质样本中元素定向搜索的快速分析技术

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-03-30 DOI: 10.2478/lpts-2024-0010

R. A. Ganeev, V. V. Kim, D. Vorobyov, U. Gross, A. Ubelis, D. Ozols, J. Butikova, J. Grube, A. Sarakovskis

{"title":"The First Application of Laser-Induced Breakdown Spectroscopy: A Fast-Analytical Technique in Targeted Search for Elements in Geological Samples from Deep Boreholes in Latvia","authors":"R. A. Ganeev, V. V. Kim, D. Vorobyov, U. Gross, A. Ubelis, D. Ozols, J. Butikova, J. Grube, A. Sarakovskis","doi":"10.2478/lpts-2024-0010","DOIUrl":"https://doi.org/10.2478/lpts-2024-0010","url":null,"abstract":"\u0000 Laser-induced breakdown spectroscopy (LIBS) provides a rapid, cost-effective, and extra-sensitive analysis of geological samples to make preliminary conclusions about the presence of valuable elements up to the trace levels in the ore. We present the first results of a highly sensitive qualitative analysis of the core samples of geological ore from two boreholes in Latvia (Staicele 1, from a depth range of 794–802 m, and Garsene (Subate) 2A, from a depth range of 1102–1103 m) using LIBS. Our measurements using this technique confirmed the high iron content and indicated traces of rare and high in-demand metals (such as Ti, V, Co, Sm, etc.) in the sample from Staicele, renewing interest in studying boreholes across Latvia. The presented pilot studies demonstrated effectiveness and unique possibility in performing a very sensitive and time-saving qualitative analysis of the composition of samples of ores from the old but still valuable borehole cores by using the LIBS method. We compare these measurements with other methods of sample analysis.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140364027","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

General and Complete Synchronization of Mutual Coupling System of Quantum Dot Semiconductor Lasers With Optical Feedback 带光反馈的量子点半导体激光器相互耦合系统的一般和完全同步化

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-02-01 DOI: 10.2478/lpts-2024-0007

O. H. Abdulkareem, R. H. Abdali, B. A. Ghalib

引用次数: 0

A Practical Solution to Reduce Interference from Led Lights 减少 LED 灯干扰的实用解决方案

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-02-01 DOI: 10.2478/lpts-2024-0004

J. Kallunki

{"title":"A Practical Solution to Reduce Interference from Led Lights","authors":"J. Kallunki","doi":"10.2478/lpts-2024-0004","DOIUrl":"https://doi.org/10.2478/lpts-2024-0004","url":null,"abstract":"\u0000 The study explores the detection of a harmful, wide-band interference signal, whose origin is a traditional desk LED (light-emitting diode) lamp. The interference signal was noticed on the sensitive solar spectrometer observing system, which was operating at a frequency range between 100 and 300 MHz. The interference signal was so strong and wide-band that it destroyed totally the solar observations. The study introduces two practical EMI (Electromagnetic Interference) reducing methods: ferrite cores and shielding (shielding effectiveness, S.E.). Their theoretical background is presented, and, in addition, these methods are tested in practice. The measurements and tests showed that even simple ferrite core was a very effective method to reduce interference effects. It is important that a suitable setup will be found: a single ferrite core cannot solve a whole problem. This interference problem is very demonstrative and it can be used in educational purposes at an undergraduate level at Metropolia University of Applied Sciences, Finland. This study reveals the fact that standard lamps, which are on the market, do not necessarily follow good EMC (Electromagnetic Compatibility) practices.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139875641","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

Exposure Buildup Factors in Concrete, Lead for Point Isotropic and Unidirectional Photon Sources in the Energy Range from 10 to 50 MeV 10 至 50 MeV 能量范围内各向同性点光子源和单向光子源在混凝土、铅中的辐照堆积因子

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-02-01 DOI: 10.2478/lpts-2024-0002

I. Alhagaish, A. K. Aqili

引用次数: 0

Sodium Citrate and Polyvinylpyrrolidone Captured Silver Nanoparticles Transfer to Organic Solvents 柠檬酸钠和聚乙烯吡咯烷酮捕获的银纳米粒子向有机溶剂转移

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Latvian Journal of Physics and Technical Sciences Pub Date : 2024-02-01 DOI: 10.2478/lpts-2024-0003

J. Mikelsone, A. Vembris

{"title":"Sodium Citrate and Polyvinylpyrrolidone Captured Silver Nanoparticles Transfer to Organic Solvents","authors":"J. Mikelsone, A. Vembris","doi":"10.2478/lpts-2024-0003","DOIUrl":"https://doi.org/10.2478/lpts-2024-0003","url":null,"abstract":"\u0000 Silver nanoparticles (NPs) have gathered extensive attention due to their properties – chemical stability, good conductivity, catalytic activity, and antimicrobial activity. This makes NPs suitable for potential applications in the development of new technologies in the field of photonics, electronics, medicine, biochemical sensing, and imaging. Nanoprisms have local surface plasmon resonance starting from visible to near infra-red spectrum, broadening the possibilities of their applications. Ag NPs typically are synthesized in aqueous solution but the handling of NPs often requires their dispersion into nonpolar solvents and their mixing with organic compounds. Thus, nanoparticle transfer to organic media is essential for application in the field of emission enhancement due to NPs – organic semiconductor interaction. A shell changing method for NP tranfer was successfully used with a high transfer rate, but rather low stability. The previously proposed sonochemical method for NP transfer from aqueous to organic polymeric media is extended to different organic solvents. The ultrasonic method is suitable to obtain stable NPs in both organic solvent and organic solvent/organic compound solutions, and it can be stored at ambient conditions for at least several months. Transfer efficiency is suficient and NPs remain stable in an organic solvent like chlorobenzene, anisole, dichloromethane. The method has potential in NPs containing thin film preparation because sonication prevents the agglomeration of clusters.","PeriodicalId":43603,"journal":{"name":"Latvian Journal of Physics and Technical Sciences","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139880655","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