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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
Q4 PHYSICS, APPLIED Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0028
L. Smelkovs, V. Viksna, J. Teterovskis, J. Grube
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.
近年来,上转换发光纳米粒子因其高发射效率、易于表面功能化、具有良好的化学稳定性和光稳定性等优点,在分析化学(如金属和非金属离子的定性和定量分析)和生物医学(癌症成像、药物传递、治疗等)等领域受到了研究人员的广泛关注。特别是nayf4作为宿主材料,由于其声子能量低,从而提高了发射效率,引起了研究人员的兴趣。本研究成功地采用水热法制备了nayf4: yb3 +,Tm 3+纳米晶体。采用含油酸的精制葵花油代替分析级油酸和十八烯-1作为溶剂,降低了合成成本。通过半定量XRD测量分析,合成样品中含有25.3%的六方β- nayf4: yb3 +,Tm 3+和23.8%的立方α- nayf4纳米晶相。样品的发光特征主要表现为六方晶型纳米颗粒(nayf4: yb3 +,Tm 3+)。
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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
Q4 PHYSICS, APPLIED Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0030
L. Zemite, L. Jansons, N. Zeltins, S. Lappuke, I. Bode
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.
现有的欧盟天然气网络为可再生能源(RGs)和低碳气体的整合提供了很大的容量。如今,氢仅占欧洲能源消耗的百分之几,几乎完全由化石燃料生产并用于工业。然而,氢在难以脱碳的部门的减少排放方面可发挥重要作用,特别是作为运输应用的燃料和作为某些工业过程(钢铁、炼油或化学工业、“绿色肥料”的生产)的燃料或原料。与氢反应的二氧化碳(CO 2)还可以进一步加工成合成燃料,例如航空中的合成煤油。此外,氢作为燃料使用时还会带来其他环境效益,例如减少空气污染物的排放。然而,在从化石燃料到天然气的过渡阶段,即可再生或绿色氢气、天然气/生物甲烷和氢气混合物,需要逐步取代现有天然气输配网络中的天然气。天然气网络被认为能够使用天然气/生物甲烷和氢气的混合物,氢气的体积为5 - 20%。大多数系统和应用程序都能够处理它,而不需要主要的基础设施升级或终端设备改造或更换。欧洲氢干线(EHB)等氢网络在欧洲的推广势头正猛。为了使天然气电网脱碳,必须提高现有电网系统中氢气的门槛,这可以通过在当前运行的天然气网络中更广泛的天然气/生物甲烷和氢气混合以及同时运输来实现。
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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
Q4 PHYSICS, APPLIED Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0032
A. Korenkovs, E. Gerins, A. Kromanis
Abstract Near–dry machining and dry machining lead to increased temperature of the cutting tools. To reduce tool wear and extend the tool lifetime, and, eventually, to keep the accuracy of manufactured parts within acceptable limits as long as possible, a sustainable cooling technique is required. The technology of internal cooling of the cutting tool appears to be the most promising, because it allows eliminating the presence of the coolant on the manufacturing part and delivers the heat–transferring fluid to the very cutting area of the tool. This paper provides a literature review on the closed–loop internally cooled cutting tools (CLICCT) for turning. The current level of knowledge and experimental machining with prototypes has proven that CLICCT can utilize the benefits of dry cooling, having a longer tool life.
近干式加工和干式加工导致刀具温度升高。为了减少刀具磨损,延长刀具寿命,并最终使制造零件的精度尽可能长地保持在可接受的范围内,需要一种可持续的冷却技术。刀具内部冷却技术似乎是最有前途的,因为它可以消除制造部件上冷却剂的存在,并将传热流体输送到刀具的切割区域。本文对车削用闭环内冷刀具(CLICCT)进行了综述。目前的知识水平和原型的实验加工已经证明,CLICCT可以利用干冷却的好处,具有更长的刀具寿命。
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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
Q4 PHYSICS, APPLIED 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
Abstract Optical thermometers are advantageous for temperature measurement in electromagnetic fields and aggressive environments; however, their composition mostly relies on materials doped with expensive and resource-limited rare earth ions. In this article, we describe the application of calcium aluminate doped with transition metal ions (Mn 2+ and Cr3+) in optical thermometry, employing optical fibres for signal transmission. Upon excitation with 450 nm laser diode radiation, changes in the luminescence of Mn 2+ ions in the 500–550 nm band are followed along with changes in the Cr 3+ band at 750–800 nm. The application has been tested in the temperature range from 20 °C to 800 °C. The temperature dependence of Cr 3+ luminescence encompasses the high-temperature range, whereas the luminescence band of Mn 2+ ions gives an increase in the total intensity and provides a more consistent change in the range from 400 °C to 550 °C.
光学温度计在电磁场和腐蚀性环境中具有测量温度的优势;然而,它们的组成主要依赖于掺杂昂贵且资源有限的稀土离子的材料。本文描述了掺杂过渡金属离子(Mn 2+和Cr3+)的铝酸钙在光学测温中的应用,采用光纤进行信号传输。在450nm激光二极管辐射激发下,在500 ~ 550nm波段Mn 2+离子的发光随Cr 3+在750 ~ 800nm波段的发光变化而变化。该应用程序已在20°C至800°C的温度范围内进行了测试。cr3 +发光的温度依赖性包括高温范围,而Mn 2+离子的发光带使总强度增加,并在400°C至550°C范围内提供更一致的变化。
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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
Q4 PHYSICS, APPLIED Pub Date : 2023-09-29 DOI: 10.2478/lpts-2023-0029
K. Gicevskis, O. Linkevics
Abstract This article evaluates the feasibility of using electrode boiler in grid ancillary services and district heating scenarios. Electrode boilers in the context of electricity grid management can be considered as a relatively new technology. This study assesses the technical and economic viability of electrode boiler by considering various factors such as energy demand, technical feasibility, economic viability, and regulatory market conditions. The simplified mathematical model has been developed for simulation of electrode boiler use for grid services and heat production. The results have shown that electrode boiler have the potential to be a cost-effective solution for heating and grid balancing services in certain scenarios. However, it may not be applicable or economically viable in all situations or regions; thus, further research and development is needed to fully realize their potential.
摘要本文评估了在电网辅助服务和区域供热场景中使用电极锅炉的可行性。在电网管理的背景下,电极锅炉可以被认为是一项相对较新的技术。本研究通过考虑能源需求、技术可行性、经济可行性和监管市场条件等多种因素来评估电极锅炉的技术和经济可行性。建立了用于电网服务和产热的电极锅炉的简化数学模型。结果表明,在某些情况下,电极锅炉具有成为供热和电网平衡服务的经济有效解决方案的潜力。但是,它可能不适用于所有情况或区域,或在经济上不可行;因此,需要进一步的研究和开发,以充分发挥其潜力。
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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 Q4 PHYSICS, APPLIED Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0023
K. Carjova, M. Banov, L. Vinogradov, S. Kravchenko, G. Strautmanis
Abstract The article reviews the capacities of the acoustic emission method usage to assess the technical condition and integrity of thick-walled welded structures, the quality control of welded joints in multilayer welding. As a result of the analysis of AE control data, the authors propose a set of informative parameters of the AE method, which form a criterion space for separating the reflected signals from defects and signals from interference.
摘要本文综述了声发射法在厚壁焊接结构的技术条件和完整性评定、多层焊接中焊接接头质量控制等方面的应用。通过对声发射控制数据的分析,提出了一套声发射方法的信息参数,这些参数构成了分离反射信号与缺陷信号和干扰信号的判据空间。
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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 Q4 PHYSICS, APPLIED Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0022
V. Bezrukovs, V. Bezrukovs, M. Konuhova, D. Bezrukovs, I. Kaldre, A. Berzins
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.
摘要本文介绍了一种用于增压压缩机的液压氢气压缩解决方案。它可以适用于改变氢气入口压力的参数,并允许稳定高压存储器中的氢气积聚过程。本研究的主要结果是使用一个数值模型获得的,该模型旨在探索氢气液压压缩过程中发生的热力学过程。使用COMSOL Multiphysics®6.0软件以及CFD和传热模块进行建模。在计算模型中使用了体积为1.14l、壁厚为5mm的圆柱体形式的压缩室。这些模拟的目的是研究氢气、气缸壁和工作流体的温度变化极限,并估计气缸内压力的实际值。考虑到气缸内部温度的升高,考虑到气缸室内压力升高的过程被建模为充满工作流体的体积的连续变化,离散时间步长为0.01s。给出了从0.5到20.0 s的不同压缩冲程持续时间ts的推导建模结果。在初始氢气压力P1=3.0、10.0、15.0和20.0MPa以及压缩比Kc=5.0的情况下,计算了压缩过程中的能耗和温升曲线。热力学过程的模拟结果及其分析允许估计液压压缩系统中的能量消耗,并确定将导致所考虑的氢气压缩操作系统的效率提高的条件。
{"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 Q4 PHYSICS, APPLIED Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0024
N. Remez, A. Dychko, A. Kraychuk, S. Kraychuk, N. Ostapchuk
Abstract The present paper provides the dependence of the temperature change on time and the depth of the soil massif based on numerical calculations. Mathematical modelling of the one-dimensional soil temperature field via an algorithm and a PC program is carried out without taking into account the influence of the phase transition of moisture in the soil pores during seasonal freezing and thawing using the finite difference method. The amplitude of fluctuations in the temperature regime is obtained as that decreases with depth from the soil surface. It is established that over time heat spreads from the pipeline to the surface of the soil, and over time more intense heating occurs both near the pipeline and in the body of the soil massif.
摘要基于数值计算,给出了温度变化对时间和土体深度的依赖关系。在不考虑季节冻融过程中孔隙水分相变影响的情况下,采用有限差分法对一维土壤温度场进行了数学建模。温度波动的幅度是随着距离土壤表面的深度而减小的。可以确定,随着时间的推移,热量从管道传播到土壤表面,并且随着时间的推移,在管道附近和土体内部都发生了更强烈的加热。
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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 Q4 PHYSICS, APPLIED Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0021
I. Zālītis, A. Dolgicers, J. Kozadajevs, J. Berkolds
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.
摘要本文提出了一种自适应输电线路故障定位方法,该方法在线路两端结合了故障定位设备,并利用从监控和数据采集系统导入的数据,而无需严格要求数据同步。所开发的方法旨在实现更高程度的鲁棒性、适应性和准确性。自适应性是通过动态更新基于全网信息使用的数学模型来实现的,例如关于断路器状态的数据以及负载和发电节点的视在功率。通过结合模型参数识别的两个阶段来增强鲁棒性和准确性,目的是减少识别故障参数阶段的决策变量空间。此外,除了利用特定变电站的所有可用测量值外,与基于确定性模型的方法不同,所开发的方法通过结果交叉检查部分利用了线路另一端的测量值,但不需要完整的数据集。基于优化的方法、基于扩展测量集的冗余和交叉检查降低了由于测量误差或可用数据中的“空白”而导致的故障定位误差的风险。对所开发方法的测试表明,即使在考虑各种故障前突发事件的情况下,该方法在广泛的故障前和故障状态场景中也具有准确性和稳健性。
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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 Q4 PHYSICS, APPLIED Pub Date : 2023-08-01 DOI: 10.2478/lpts-2023-0026
M. Hamideen, A. Chandrasekaran, M. A. Neelakantan
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.
摘要铀是岩石圈的特征成分,几乎存在于各种土壤和水体中;在任何情况下,它的量在不同的水之间变化取决于它们的原因。随后,在本次调查中,利用LED荧光仪估计了地下水测试中的铀浓度,并对相关的健康危害评估进行了检查。铀的浓度范围为0.5 ~ 10.7 μg L−1,平均值为2.76 μg L−1。在1.416×10−6 - 30.309×10−6的范围内,癌症风险过高,平均为7.804 ×10−6。Kanchipuram地区过量癌症风险的平均估计值低于AERB(2004)的最大适当度1.67 × 10−4。因此,对在检测区域内吞食水的邻近个体没有伤害性影响。利用铀的化学危害性的危害商,确定了平均癌症死亡率和严酷机会,表明与水试验和显著健康有关的致癌机会的可能性。在检查中观察到的所有区域的危险商值都低于USEPA推荐的1的边缘估计。说明在调查区域内对附近个体没有不安全影响。
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引用次数: 0
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Latvian Journal of Physics and Technical Sciences
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