Pub Date : 2023-11-07DOI: 10.14311/ap.2023.63.0356
Jan Rataj, Jakub Mátl, Pavel Suk
This paper describes the application of the Source-Jerk method using a neutron generator in the VR-1 reactor. The experiments were carried out on a shutdown reactor with subcriticality greater than -10 βeff. A D-D neutron generator located in the radial channel of the VR-1 reactor was used as an external neutron source for the Source-Jerk method. The obtained results were discussed and compared with a conventional Source-Jerk method used at the VR-1 reactor and with the values calculated by the Serpent 2 code. The presented experimental works and their results will allow to extend the methods of reactivity measurements on the VR-1 reactor. They will also help to optimise reactivity measurements on the new subcritical reactor VR-2, which is currently being commissioned at the Czech Technical University in Prague.
{"title":"Application of the Source-Jerk method using a neutron generator in a subcritical reactor","authors":"Jan Rataj, Jakub Mátl, Pavel Suk","doi":"10.14311/ap.2023.63.0356","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0356","url":null,"abstract":"This paper describes the application of the Source-Jerk method using a neutron generator in the VR-1 reactor. The experiments were carried out on a shutdown reactor with subcriticality greater than -10 βeff. A D-D neutron generator located in the radial channel of the VR-1 reactor was used as an external neutron source for the Source-Jerk method. The obtained results were discussed and compared with a conventional Source-Jerk method used at the VR-1 reactor and with the values calculated by the Serpent 2 code. The presented experimental works and their results will allow to extend the methods of reactivity measurements on the VR-1 reactor. They will also help to optimise reactivity measurements on the new subcritical reactor VR-2, which is currently being commissioned at the Czech Technical University in Prague.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"263-264 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139284699","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}
Pub Date : 2023-11-07DOI: 10.14311/ap.2023.63.0293
Fares Belynda, R. Abdelli, A. Bouzida
This paper presents a novel method for modelling and diagnosis of electrical and mechanical faults in fixed-Speed Self-Excited Induction Generators (SEIGs) operating in autonomous mode in a small-scale wind energy system. The proposed method is validated using the finite element method. After the selection of the magnetising capacitors, the self-excitation process is performed under no-load conditions. Once the stator voltage is established, a symmetrical three-phase load is connected. The fault detection method introduced here is called Stator Current Signal Crossing (SCSC). The SCSC extracts a new signal from the stator currents, that enables the detection of stator inter turn shortcircuits, broken rotor bars, and dynamic eccentricity faults in SEIGs. A spectral analysis of SCSC using the Fast Fourier Transform (FFT) algorithm is used to precisely locate the induced fault components. What sets this fault-tracking method apart from its predecessors is its exceptional ability to detect faults of any magnitude by analysing the modulation of the SCSC signal. These faults are directly identified by the presence of distinct harmonics, each indicative of a specific type of fault. This study also focuses on the SEIG in a wind energy system, whereas previous works have mainly addressed the induction machine in motor mode. In contrast, previous methods involved analysing a single current signal and isolating specific harmonics from a wide frequency range. The effectiveness of the proposed fault detection method and the self-excitation process are illustrated by simulation results and spectral analysis.
{"title":"Stator current signal crossing for fault diagnosis of self-excited induction generators","authors":"Fares Belynda, R. Abdelli, A. Bouzida","doi":"10.14311/ap.2023.63.0293","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0293","url":null,"abstract":"This paper presents a novel method for modelling and diagnosis of electrical and mechanical faults in fixed-Speed Self-Excited Induction Generators (SEIGs) operating in autonomous mode in a small-scale wind energy system. The proposed method is validated using the finite element method. After the selection of the magnetising capacitors, the self-excitation process is performed under no-load conditions. Once the stator voltage is established, a symmetrical three-phase load is connected. The fault detection method introduced here is called Stator Current Signal Crossing (SCSC). The SCSC extracts a new signal from the stator currents, that enables the detection of stator inter turn shortcircuits, broken rotor bars, and dynamic eccentricity faults in SEIGs. A spectral analysis of SCSC using the Fast Fourier Transform (FFT) algorithm is used to precisely locate the induced fault components. What sets this fault-tracking method apart from its predecessors is its exceptional ability to detect faults of any magnitude by analysing the modulation of the SCSC signal. These faults are directly identified by the presence of distinct harmonics, each indicative of a specific type of fault. This study also focuses on the SEIG in a wind energy system, whereas previous works have mainly addressed the induction machine in motor mode. In contrast, previous methods involved analysing a single current signal and isolating specific harmonics from a wide frequency range. The effectiveness of the proposed fault detection method and the self-excitation process are illustrated by simulation results and spectral analysis.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"127 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139285283","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}
Pub Date : 2023-11-07DOI: 10.14311/ap.2023.63.0347
Alisettar Hüseynli, Mehmet Şimşek, M. Akcayol
The Stream Control Transmission Protocol (SCTP) is often the preferred transport layer protocol in streaming applications. This protocol combines the best aspects of Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), but also offers additional features. SCTP supports multihoming and multi-streaming applications and has a congestion mechanism like TCP. Media streaming consists of different types of frames with different levels of importance. For example, I-frames carry more information than B-frames in Moving Picture Experts Group (MPEG). Usually, MPEG frames are processed using the First-In-First-Out (FIFO) algorithm. In this paper, a four-level priority queue integrated protocol named SCTP Priority Queue (SCTP-PQ) has been developed to reduce jitter and delay in real-time multimedia streaming for mobile devices. As part of the development, priority and retransmitted packets are determined on the sending side and these packets are processed faster by using the priority queue on the receiving side. In this way, the average queue delay of priority packets on the receiving side is reduced by 90 % and the throughput values are increased by an average of 10 times. The developed protocol has been extensively tested and compared with SCTP. The results show that the SCTP-PQ outperforms the standard SCTP in terms of jitter and delay.
{"title":"Improving QoS in mobile multimedia streaming with SCTP-PQ","authors":"Alisettar Hüseynli, Mehmet Şimşek, M. Akcayol","doi":"10.14311/ap.2023.63.0347","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0347","url":null,"abstract":"The Stream Control Transmission Protocol (SCTP) is often the preferred transport layer protocol in streaming applications. This protocol combines the best aspects of Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), but also offers additional features. SCTP supports multihoming and multi-streaming applications and has a congestion mechanism like TCP. Media streaming consists of different types of frames with different levels of importance. For example, I-frames carry more information than B-frames in Moving Picture Experts Group (MPEG). Usually, MPEG frames are processed using the First-In-First-Out (FIFO) algorithm. In this paper, a four-level priority queue integrated protocol named SCTP Priority Queue (SCTP-PQ) has been developed to reduce jitter and delay in real-time multimedia streaming for mobile devices. As part of the development, priority and retransmitted packets are determined on the sending side and these packets are processed faster by using the priority queue on the receiving side. In this way, the average queue delay of priority packets on the receiving side is reduced by 90 % and the throughput values are increased by an average of 10 times. The developed protocol has been extensively tested and compared with SCTP. The results show that the SCTP-PQ outperforms the standard SCTP in terms of jitter and delay.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"82 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139283521","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}
Pub Date : 2023-11-07DOI: 10.14311/ap.2023.63.0320
Jakub Durica, R. Sovják, Martin Boroš, Radoslav Kuffa
Perimeter security defines the private space from the public space and also serves as the first barrier between the intruder and the protected interest. Delay time is one of the input parameters used in a quantitative approach to the design of a physical protection system. The objective of the physical protection system is to delay the intruder long enough for the law enforcement to arrive on the scene and apprehend the intruder. Perimeter protection is located in the exterior and is affected by various factors such as ambient temperature. In cold temperatures, the technical parameters deteriorate and the delay time for penetration into the protected object decreases. The paper points out that the delay time is longest at 0 °C and that the delay time decreases as the ambient temperature increases. A further perspective is mentioned on the adaptation of the tests and increasing the degree of subjectivity of the test results.
周界安全是私人空间与公共空间的分界线，也是入侵者与受保护利益之间的第一道屏障。延迟时间是实物保护系统设计定量方法中使用的输入参数之一。实物保护系统的目标是将入侵者拖延足够长的时间，以便执法人员到达现场并逮捕入侵者。外围保护位于室外，受环境温度等各种因素的影响。在低温条件下，技术参数会变差，侵入被保护对象的延迟时间也会缩短。文件指出，延迟时间在 0 °C 时最长，随着环境温度的升高，延迟时间会缩短。论文还从另一个角度阐述了如何调整测试和提高测试结果的主观性。
{"title":"The effect of ambient temperature on the delay time of perimeter protection","authors":"Jakub Durica, R. Sovják, Martin Boroš, Radoslav Kuffa","doi":"10.14311/ap.2023.63.0320","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0320","url":null,"abstract":"Perimeter security defines the private space from the public space and also serves as the first barrier between the intruder and the protected interest. Delay time is one of the input parameters used in a quantitative approach to the design of a physical protection system. The objective of the physical protection system is to delay the intruder long enough for the law enforcement to arrive on the scene and apprehend the intruder. Perimeter protection is located in the exterior and is affected by various factors such as ambient temperature. In cold temperatures, the technical parameters deteriorate and the delay time for penetration into the protected object decreases. The paper points out that the delay time is longest at 0 °C and that the delay time decreases as the ambient temperature increases. A further perspective is mentioned on the adaptation of the tests and increasing the degree of subjectivity of the test results.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"52 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139284072","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}
Pub Date : 2023-11-07DOI: 10.14311/ap.2023.63.0364
Azlan Yusof, A. Idris, Ezmin Abdullah
The Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) is a 5G multicarrier waveform that offers great data speeds and improvements in spectrum utilisation. The primary CP-OFDM’s weakness is its excessive peak-to-average power ratio (PAPR), which is a characteristic of all multicarrier modulation techniques. We study the application of a hybrid technique approach how to lower the peak to average power ratio (PAPR) in a CP-OFDM system. We also evaluated the outcomes of peak to average power ratio (PAPR) decrease in CP-OFDM, utilising a hybrid technique with Group Codeword Shift (GCS), Median Codeword Shift, Selective Codeword Shift (SCS), and Conventional CP-OFDM. When compared to the non-hybrid technique, the simulation results indicate that the hybrid approach is superior in reducing the peak PAPR by more than 65 percent.
{"title":"PAPR reduction in CP-OFDM (5G) using hybrid technique","authors":"Azlan Yusof, A. Idris, Ezmin Abdullah","doi":"10.14311/ap.2023.63.0364","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0364","url":null,"abstract":"The Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) is a 5G multicarrier waveform that offers great data speeds and improvements in spectrum utilisation. The primary CP-OFDM’s weakness is its excessive peak-to-average power ratio (PAPR), which is a characteristic of all multicarrier modulation techniques. We study the application of a hybrid technique approach how to lower the peak to average power ratio (PAPR) in a CP-OFDM system. We also evaluated the outcomes of peak to average power ratio (PAPR) decrease in CP-OFDM, utilising a hybrid technique with Group Codeword Shift (GCS), Median Codeword Shift, Selective Codeword Shift (SCS), and Conventional CP-OFDM. When compared to the non-hybrid technique, the simulation results indicate that the hybrid approach is superior in reducing the peak PAPR by more than 65 percent.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"22 3 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139284812","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}
Pub Date : 2023-11-07DOI: 10.14311/ap.2023.63.0305
Chemesse ennehar Bencheriet, Hiba Abdelmoumène, A. Sebbagh, Abdennour Yahiyaoui, Zahra Taba
Due to the robustness of the deep learning tools used to design these applications, fakes are becoming increasingly common as these applications become more widely available and accessible to the general public. These fakes are typically fake faces or even fake people, which are difficult to distinguish from real individuals. Therefore, we need more efficient applications for fraud detection. In this work, we propose a new multi-discriminator architecture to distinguish fake faces from real ones. The architecture consists of three deep networks (discriminators) competing with each other, each trained differently. The final decision is made by voting based on the decisions of the three discriminators. The core element of our architecture is the proposed new adversarial deep network discriminator (NDGAN), which is trained in three different ways, resulting in three distinct discriminators. Discriminator 1 undergoes adversarial training, discriminator 2 is trained using transfer learning, and the third discriminator undergoes supervised training with a standard CNN using examples and counterexamples. Training and testing were performed on 70 000 real faces from the Flickr-Face-HQ (FFHQ) dataset, while 70 000 fake faces were generated using Nvidia’s StyleGAN. The tests conducted on the three networks produced significant results, with accuracy ranging from 79 % to 98 % for fake faces, and from 80 % to 98 % for real faces. The reliability of the discriminators contributes significantly to the overall performance of the multi-discriminator system, achieving an accuracy of 96 % for fake faces and 98 % for real faces.
{"title":"Fake face detection based on a multi discriminator deep CNN architecture (MDD-CNN)","authors":"Chemesse ennehar Bencheriet, Hiba Abdelmoumène, A. Sebbagh, Abdennour Yahiyaoui, Zahra Taba","doi":"10.14311/ap.2023.63.0305","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0305","url":null,"abstract":"Due to the robustness of the deep learning tools used to design these applications, fakes are becoming increasingly common as these applications become more widely available and accessible to the general public. These fakes are typically fake faces or even fake people, which are difficult to distinguish from real individuals. Therefore, we need more efficient applications for fraud detection. In this work, we propose a new multi-discriminator architecture to distinguish fake faces from real ones. The architecture consists of three deep networks (discriminators) competing with each other, each trained differently. The final decision is made by voting based on the decisions of the three discriminators. The core element of our architecture is the proposed new adversarial deep network discriminator (NDGAN), which is trained in three different ways, resulting in three distinct discriminators. Discriminator 1 undergoes adversarial training, discriminator 2 is trained using transfer learning, and the third discriminator undergoes supervised training with a standard CNN using examples and counterexamples. Training and testing were performed on 70 000 real faces from the Flickr-Face-HQ (FFHQ) dataset, while 70 000 fake faces were generated using Nvidia’s StyleGAN. The tests conducted on the three networks produced significant results, with accuracy ranging from 79 % to 98 % for fake faces, and from 80 % to 98 % for real faces. The reliability of the discriminators contributes significantly to the overall performance of the multi-discriminator system, achieving an accuracy of 96 % for fake faces and 98 % for real faces.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"13 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139286876","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}
Inverse kinematics is a fundamental concept in robotics that plays a crucial role in a robot’s ability to perform tasks. In this contribution, we propose a novel geometric approach based on vector calculus to solve the inverse kinematics problem. The primary advantage of this approach originates from the solutions, which exhibit a linear form and uncoupled equations. To validate the effectiveness and correctness of our proposed method, we constructed a six-degrees-of-freedom robot. This robot is controlled by an Arduino Mega 2650 on which we have implemented the inverse kinematics algorithm. The validation process involved considering various desired trajectories of the end-effector, which were simulated in Matlab and then performed by the physical robot. Importantly, our findings confirm that the end-effector successfully tracks the predefined trajectories. Furthermore, we conducted a comparative analysis between Paul’s method and the results obtained from joint angles using our proposed approach. Interestingly, our study reveals a significant similarity between the two sets of results, reaffirming the accuracy and validity of the approach presented in this study.
逆运动学是机器人学中的一个基本概念，对机器人执行任务的能力起着至关重要的作用。在本文中，我们提出了一种基于矢量微积分的新型几何方法来解决逆运动学问题。这种方法的主要优势在于其解决方案呈现出线性形式和非耦合方程。为了验证我们提出的方法的有效性和正确性，我们构建了一个六自由度机器人。该机器人由 Arduino Mega 2650 控制，我们在其上实现了逆运动学算法。验证过程包括考虑末端执行器的各种预期轨迹，这些轨迹在 Matlab 中进行模拟，然后由实体机器人执行。重要的是，我们的研究结果证实，末端执行器能成功跟踪预定轨迹。此外，我们还对保罗的方法和使用我们提出的方法从关节角度获得的结果进行了比较分析。有趣的是，我们的研究发现这两组结果之间存在显著的相似性，再次证实了本研究提出的方法的准确性和有效性。
{"title":"Geometric approach to solving inverse kinematics of six DOF robot with spherical joints","authors":"Nacer Hadidi, Mohamed Bouaziz, Chawki Mahfoudi, Mohamed Zaharuddin","doi":"10.14311/ap.2023.63.0326","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0326","url":null,"abstract":"Inverse kinematics is a fundamental concept in robotics that plays a crucial role in a robot’s ability to perform tasks. In this contribution, we propose a novel geometric approach based on vector calculus to solve the inverse kinematics problem. The primary advantage of this approach originates from the solutions, which exhibit a linear form and uncoupled equations. To validate the effectiveness and correctness of our proposed method, we constructed a six-degrees-of-freedom robot. This robot is controlled by an Arduino Mega 2650 on which we have implemented the inverse kinematics algorithm. The validation process involved considering various desired trajectories of the end-effector, which were simulated in Matlab and then performed by the physical robot. Importantly, our findings confirm that the end-effector successfully tracks the predefined trajectories. Furthermore, we conducted a comparative analysis between Paul’s method and the results obtained from joint angles using our proposed approach. Interestingly, our study reveals a significant similarity between the two sets of results, reaffirming the accuracy and validity of the approach presented in this study.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"904 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139285080","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}
Pub Date : 2023-09-05DOI: 10.14311/ap.2023.63.0273
Axel Schulze-Halberg
We generate solvable cases of the two angular equations resulting from variable separation in the three-dimensional Dunkl-Schrödinger equation expressed in spherical coordinates. It is shown that the Dunkl formalism interrelates these angular equations with trigonometric Pöschl-Teller systems. Based on this interrelation, we use point transformations and Darboux-Crum transformations to construct new solvable cases of the angular equations. Instead of the stationary energy, we use the constants due to the separation of variables as transformation parameters for our Darboux-Crum transformations.
{"title":"Construction of angular-dependent potentials from trigonometric Pöschl-Teller systems within the Dunkl formalism","authors":"Axel Schulze-Halberg","doi":"10.14311/ap.2023.63.0273","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0273","url":null,"abstract":"We generate solvable cases of the two angular equations resulting from variable separation in the three-dimensional Dunkl-Schrödinger equation expressed in spherical coordinates. It is shown that the Dunkl formalism interrelates these angular equations with trigonometric Pöschl-Teller systems. Based on this interrelation, we use point transformations and Darboux-Crum transformations to construct new solvable cases of the angular equations. Instead of the stationary energy, we use the constants due to the separation of variables as transformation parameters for our Darboux-Crum transformations.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135362145","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}
Pub Date : 2023-09-05DOI: 10.14311/ap.2023.63.0260
Samuel Akinlabi Ola, Osemudiamen Ayoposi Usifoh, Emeka Segun Nnochiri
In Nigeria, potassium permanganate (KMnO4) is used as a chemical oxidant in the removal of hydrocarbons from polluted soils and groundwater, but there is no information on the effects of KMnO4 on the geotechnical properties of the soil. In this study, KMnO4 was added separately to lateritic soil and kaolin at concentrations of 0 %, 2 %, 5% and 10 % by weight of dry soil. Each of the mixes was then subjected to grain size analysis, Atterberg limits, specific gravity, compaction, and California bearing ratio (CBR) tests. The results showed that an increase in KMnO4 from 0 % to 10 % generally decreased the values of maximum dry density (MDD), optimum moisture content (OMC) and both unsoaked and soaked CBR for both soils. In conclusion, the study shows that although KMnO4 is excellent for the remediation of contaminated sites, it reduces the geotechnical properties of soil and therefore should not be used alone (without the use of other additives) for soil stabilisation.
{"title":"The effects of potassium permanganate on the geotechnical properties of soils","authors":"Samuel Akinlabi Ola, Osemudiamen Ayoposi Usifoh, Emeka Segun Nnochiri","doi":"10.14311/ap.2023.63.0260","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0260","url":null,"abstract":"In Nigeria, potassium permanganate (KMnO4) is used as a chemical oxidant in the removal of hydrocarbons from polluted soils and groundwater, but there is no information on the effects of KMnO4 on the geotechnical properties of the soil. In this study, KMnO4 was added separately to lateritic soil and kaolin at concentrations of 0 %, 2 %, 5% and 10 % by weight of dry soil. Each of the mixes was then subjected to grain size analysis, Atterberg limits, specific gravity, compaction, and California bearing ratio (CBR) tests. The results showed that an increase in KMnO4 from 0 % to 10 % generally decreased the values of maximum dry density (MDD), optimum moisture content (OMC) and both unsoaked and soaked CBR for both soils. In conclusion, the study shows that although KMnO4 is excellent for the remediation of contaminated sites, it reduces the geotechnical properties of soil and therefore should not be used alone (without the use of other additives) for soil stabilisation.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135362143","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}
Pub Date : 2023-09-05DOI: 10.14311/ap.2023.63.0268
Tomáš Radnic, Pavel Šafařík, Martin Luxa, David Šimurda
This paper deals with the study of a flow field and namely the configuration of shock waves in a blade cascade equipped with a part-span connector called tie-boss. The cascade consists of prismatic blades formed from the mid-section of a very long last-stage blade of a steam turbine. The study is based on numerical simulations of the flow through a cascade that was previously tested in a wind tunnel. Commercial software Ansys CFX was used for the simulations and Ansys ICEM for the mesh generation. The computational domain contains non-homogenous mesh interfaces. The simulations showed that the presence of the tie-boss has a profound effect on the configuration of the shock waves. The blade exit shock waves are disturbed and new lateral shock waves are introduced into the flow.
{"title":"Shock wave configuration in a transonic flow through a mid-section of a last stage turbine blade cascade equipped with a part-span connector","authors":"Tomáš Radnic, Pavel Šafařík, Martin Luxa, David Šimurda","doi":"10.14311/ap.2023.63.0268","DOIUrl":"https://doi.org/10.14311/ap.2023.63.0268","url":null,"abstract":"This paper deals with the study of a flow field and namely the configuration of shock waves in a blade cascade equipped with a part-span connector called tie-boss. The cascade consists of prismatic blades formed from the mid-section of a very long last-stage blade of a steam turbine. The study is based on numerical simulations of the flow through a cascade that was previously tested in a wind tunnel. Commercial software Ansys CFX was used for the simulations and Ansys ICEM for the mesh generation. The computational domain contains non-homogenous mesh interfaces. The simulations showed that the presence of the tie-boss has a profound effect on the configuration of the shock waves. The blade exit shock waves are disturbed and new lateral shock waves are introduced into the flow.","PeriodicalId":45804,"journal":{"name":"Acta Polytechnica","volume":"154 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135362140","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}
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