Bulletin of the Polish Academy of Sciences-Technical Sciences最新文献_第6页

Numerical benchmarks for topology optimization of structures with stress constraints 具有应力约束的结构拓扑优化的数值基准

4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/bpasts.2021.139317

引用次数: 1

Structure and properties of suction-cast Pr-(Fe, Co)-(Zr, Nb)-B rod magnets 吸铸Pr-(Fe, Co)-(Zr, Nb)- b棒状磁体的结构与性能

4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/bpasts.2021.138971

{"title":"Structure and properties of suction-cast Pr-(Fe, Co)-(Zr, Nb)-B rod magnets","authors":"","doi":"10.24425/bpasts.2021.138971","DOIUrl":"https://doi.org/10.24425/bpasts.2021.138971","url":null,"abstract":"GFA of the alloy [5‒7]. Furthermore, doping with Zr and Nb causes the microstructure refinement of the RE-Fe-B magnets and, thus, can enhance the magnetic properties of the annealed specimens [8‒10]. As was reported in [7], the appropriate setting of the composition for the Fe67Co9.4Nd3.1Dy0.5B20 alloy led to an improvement of the GFA that allowed processing of the fully glassy rods with diameters up to 0.5 mm. A further change of composition and addition of Zr facilitated casting 1-mm diameter amorphous rods and up to 3-mm outer diameter tubes for the Fe61Co13.5Zr1Pr3.5Dy1B20 alloy [11]. However, a small amount of RE elements in the chemical composition caused the formation of a relatively low fraction of the RE2Fe14B phase. For this reason, such magnets reveal rather moderate magnetic parameters [12]. We have shown in our previous studies on rapidly solidified plates of various thicknesses produced for Pr9Fe50 + xCo13Zr1Nb4B23 – x (x = 0, 2, 5, 8) alloys that boron content greatly influences the GFA. In the case of the Pr9Fe50Co13Zr1Nb4B23 alloy, the 0.5-mm thick plates were fully amorphous while 1-mm plates were slightly crystalline and only one very low-intensity diffraction peak was detected [6, 13]. However, for alloys of lower B content, the suction cast plates were all crystalline in as-cast state. Furthermore, the critical cooling rate attainable for specific production equipment depends on the sample geometry [14]. The changes in the microstructure and magnetic properties with the sample shape were shown for the Pr9Fe52Co13Zr1Nb4B21 alloy [15]. The aim of the present work was to study the influence of the Fe to B ratio on the GFA as well as on the phase constitution, microstructure, and magnetic properties of the 1-mm diameter rods of Pr9Fe50 + xCo13Zr1Nb4B23 – x (x = 0, 5, 8) alloys in the as-cast state and those subjected to annealing. Preliminary analysis of magnetic parameters has shown that optimal magnetic","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"218 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135679937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The pointwise completeness and the pointwise degeneracy of fractional descriptor discrete-time linear systems 分数阶广义离散线性系统的点完备性和点退化性

IF 1.2 4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/BPASTS.2019.130891

T. Kaczorek

引用次数: 2

Super-resolution reconstruction of face images based on pre-amplification non-negative restricted neighborhood embedding 基于预放大非负约束邻域嵌入的人脸图像超分辨率重建

IF 1.2 4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/bpas.2018.125937

Xin Yang, D. Liu, Dake Zhou, S. Fei

引用次数: 3

Enhancement of COVID-19 symptom-based screening with quality-based classifier optimisation 以基于质量的分类器优化加强COVID-19症状筛查

IF 1.2 4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/bpasts.2021.137349

M. Kozielski, J. Henzel, J. Tobiasz, A. Gruca, P. Foszner, J. Żyła, M. Bach, A. Werner, J. Jaroszewicz, J. Polańska, M. Sikora

{"title":"Enhancement of COVID-19 symptom-based screening with quality-based classifier optimisation","authors":"M. Kozielski, J. Henzel, J. Tobiasz, A. Gruca, P. Foszner, J. Żyła, M. Bach, A. Werner, J. Jaroszewicz, J. Polańska, M. Sikora","doi":"10.24425/bpasts.2021.137349","DOIUrl":"https://doi.org/10.24425/bpasts.2021.137349","url":null,"abstract":"Efforts of the scientific community led to the development of multiple screening approaches for COVID-19 that rely on machine learning methods. However, there is a lack of works showing how to tune the classification models used for such a task and what the tuning effect is in terms of various classification quality measures. Understanding the impact of classifier tuning on the results obtained will allow the users to apply the provided tools consciously. Therefore, using a given screening test they will be able to choose the threshold value characterising the classifier that gives, for example, an acceptable balance between sensitivity and specificity. The presented work introduces the optimisation approach and the resulting classifiers obtained for various quality threshold assumptions. As a result of the research, an online service was created that makes the obtained models available and enables the verification of various solutions for different threshold values on new data. © 2021 The Author(s).","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"69 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68945679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Active-controlled two-terminal network implementing a convolution-type immittance operator 实现卷积型阻抗算子的有源控制双端网络

IF 1.2 4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/BPASTS.2020.134663

M. Siwczyński, M. Jaraczewski

引用次数: 1

A practical approach to optimal strategies of electricity contracting from Hybrid Power Sources 混合电源电力承包最优策略的实用方法

IF 1.2 4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/BPASTS.2020.135377

P. Marchel, J. Paska, K. Pawlak, Krzysztof Zagrajek

{"title":"A practical approach to optimal strategies of electricity contracting from Hybrid Power Sources","authors":"P. Marchel, J. Paska, K. Pawlak, Krzysztof Zagrajek","doi":"10.24425/BPASTS.2020.135377","DOIUrl":"https://doi.org/10.24425/BPASTS.2020.135377","url":null,"abstract":"Hybrid Power Sources/Systems (HPS) are generally treated as local prosumer supplies. The paper presents a new approach to the strategy of electricity contracting from HPS, considering hybrid systems as a new type of quasi-centrally dispatched power units operating in Polish market conditions. The possibilities of contracting electricity from HPS, consisting of three electricity generation technologies: biogas plant, wind power plant and solar power plant, are presented. The opportunity to obtain additional income from the electricity trading on the balancing market was used. Proposals for a new mathematical description of HPS topology were also presented, including a feasibility function, which can be used for technical and economic analyses. The obtained results can be used as a direction of development in the field of optimization of hybrid source operation in cooperation with the power grid. Based on the conducted analyses, it can be observed that electricity sales contracts concluded for each hour of the day may bring additional profit for the investor. However, the strong dependence of the proposed strategy on the situation on the balancing market or other local electricity markets similar in their operations should be emphasized.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"18 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74524972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Current-fed quasi-Z-source H7 inverter with reduced stress on SiC power devices 减小SiC功率器件应力的准z源电流型H7逆变器

IF 1.2 4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/BPASTS.2019.131568

Przemysław Trochimiuk, M. Zdanowski, J. Rąbkowski

{"title":"Current-fed quasi-Z-source H7 inverter with reduced stress on SiC power devices","authors":"Przemysław Trochimiuk, M. Zdanowski, J. Rąbkowski","doi":"10.24425/BPASTS.2019.131568","DOIUrl":"https://doi.org/10.24425/BPASTS.2019.131568","url":null,"abstract":". This paper discusses selected problems regarding a high-frequency improved current-fed quasi-Z-source inverter (iCFqZSI) designed and built with SiC power devices. At first, new, modified topology of the impedance network is presented. As the structure is derived from the series connection of two networks, the voltage stress across the SiC diodes and the inductors is reduced by a factor of two. Therefore, the SiC MOSFETs may be switched with frequencies above 100 kHz and volume and weight of the passive components is decreased. Furthermore, additional leg with two SiC MOSFETs working as a bidirectional switch is added to limit the current stress during the short-through states. In order to verify the performance of the proposed solution a 6 kVA laboratory model was designed to connect a 400 V DC source (battery) and a 3 £ 400 V grid. According to presented simulations and experimental results high-frequency iCFqZSI is bidirectional – it may act as an inverter, but also as a rectifier. Performed measurements show correct operation at switching frequency of 100 kHz, high quality of the input and output waveforms is observed. The additional leg increases efficiency by up to 0.6% – peak value is 97.8%.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"35 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77957114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Global stability of nonlinear feedback systemswith positive descriptor linear parts 具有正广义线性部分的非线性反馈系统的全局稳定性

IF 1.2 4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/BPAS.2019.127337

T. Kaczorek

引用次数: 3

Missing-data imputation using wearable sensors in heart rate variability 在心率变异性中使用可穿戴传感器的缺失数据输入

IF 1.2 4区工程技术

Bulletin of the Polish Academy of Sciences-Technical Sciences Pub Date : 2023-11-06 DOI: 10.24425/BPASTS.2020.133118

A. Tlija, K. Wegrzyn-Wolska, D. Istrate

{"title":"Missing-data imputation using wearable sensors in heart rate variability","authors":"A. Tlija, K. Wegrzyn-Wolska, D. Istrate","doi":"10.24425/BPASTS.2020.133118","DOIUrl":"https://doi.org/10.24425/BPASTS.2020.133118","url":null,"abstract":"The objective of this work is to set up a methodology that considers missing data from a connected heartbeat sensor in order to propose a good replacement methodology in the context of heart rate variability (HRV) computation. The framework is a research project, which aims to build a system that can measure stress and other factors influencing the onset and development of heart disease. The research encompasses studying existing methods, and improving them by use of experimental data from case study that describe the participant’s everyday life. We conduct a study to modelize stress from the HRV signal, which is extracted from a heart rate monitor belt connected to a smart watch. This paper describes data recording procedure and data imputation methodology. Missing data is a topic that has been discussed by several authors. The manuscript explains why we choose spline interpolation for data values imputation. We implement a random suppression data procedure and simulate removed data. After that, we implement several algorithms and choose the best one for our case study based on the mean square error.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"46 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79621227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2