Pub Date : 2023-12-13DOI: 10.3390/inventions8060157
Tao Yang, Chuandong Lin, Demei Li, Huilin Lai
The Richtmyer–Meshkov instability in a two-component system during the reshock process for various density ratios is studied through the discrete Boltzmann method. Detailed investigations are conducted on both hydrodynamic and thermodynamic non-equilibrium behaviors. Specifically, the analysis focuses on the density gradient, viscous stress tensor, heat flux strength, thermodynamic non-equilibrium intensity, and thermodynamic non-equilibrium area. It is interesting to observe the complex variations to non-equilibrium quantities with the changing shock front, rarefaction wave, transverse wave, and material interface. Physically, the non-equilibrium area is extended as the perturbed material interface grows after the passing of the shock wave or secondary impact. Moreover, the global non-equilibrium manifestation decreases when the transmitted shock front and transverse waves leave or when the reflected rarefaction wave weakens. Additionally, the global thermodynamic non-equilibrium effect is enhanced as the physical gradients or non-equilibrium area increase. Finally, the local non-equilibrium effect decreases when the fluid structure gradually disappears under the action of dissipation/diffusion.
{"title":"Influence of Density Ratios on Richtmyer–Meshkov Instability with Non-Equilibrium Effects in the Reshock Process","authors":"Tao Yang, Chuandong Lin, Demei Li, Huilin Lai","doi":"10.3390/inventions8060157","DOIUrl":"https://doi.org/10.3390/inventions8060157","url":null,"abstract":"The Richtmyer–Meshkov instability in a two-component system during the reshock process for various density ratios is studied through the discrete Boltzmann method. Detailed investigations are conducted on both hydrodynamic and thermodynamic non-equilibrium behaviors. Specifically, the analysis focuses on the density gradient, viscous stress tensor, heat flux strength, thermodynamic non-equilibrium intensity, and thermodynamic non-equilibrium area. It is interesting to observe the complex variations to non-equilibrium quantities with the changing shock front, rarefaction wave, transverse wave, and material interface. Physically, the non-equilibrium area is extended as the perturbed material interface grows after the passing of the shock wave or secondary impact. Moreover, the global non-equilibrium manifestation decreases when the transmitted shock front and transverse waves leave or when the reflected rarefaction wave weakens. Additionally, the global thermodynamic non-equilibrium effect is enhanced as the physical gradients or non-equilibrium area increase. Finally, the local non-equilibrium effect decreases when the fluid structure gradually disappears under the action of dissipation/diffusion.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"179 S445","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139006136","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}
Surface-enhanced Raman spectroscopy (SERS) is widely used as a detection method in scientific research fields. However, the method for creating SERS substrates often requires expensive equipment and involves a complex process. Additionally, preserving and effectively utilizing SERS substrates in the long term poses a challenging problem. In order to address these issues, we propose a new method for creating SERS substrates on various types of paper using a combination of a ballpoint pen and 3D printing. This method ensures a high enhancement factor and maximizes the utilization of the substrate. We achieved an enhancement factor of up to 8.2 × 108 for detecting R6G molecules, with a relative standard deviation of 11.13% for the Raman peak at 612 cm−1 of R6G, demonstrating excellent SERS sensitivity and spectral reproducibility. Furthermore, we successfully detected thiram at a concentration as low as 10−8, which is lower than both the Chinese national standard and European standard.
{"title":"A Surface-Enhanced Raman Spectroscopic Sensor Pen","authors":"Zejiang Song, Zhijie Li, Weishen Zhan, Wanli Zhao, Hisang-Chen Chui, Rui Li","doi":"10.3390/inventions8060156","DOIUrl":"https://doi.org/10.3390/inventions8060156","url":null,"abstract":"Surface-enhanced Raman spectroscopy (SERS) is widely used as a detection method in scientific research fields. However, the method for creating SERS substrates often requires expensive equipment and involves a complex process. Additionally, preserving and effectively utilizing SERS substrates in the long term poses a challenging problem. In order to address these issues, we propose a new method for creating SERS substrates on various types of paper using a combination of a ballpoint pen and 3D printing. This method ensures a high enhancement factor and maximizes the utilization of the substrate. We achieved an enhancement factor of up to 8.2 × 108 for detecting R6G molecules, with a relative standard deviation of 11.13% for the Raman peak at 612 cm−1 of R6G, demonstrating excellent SERS sensitivity and spectral reproducibility. Furthermore, we successfully detected thiram at a concentration as low as 10−8, which is lower than both the Chinese national standard and European standard.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"13 23","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138977178","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 : 2023-12-11DOI: 10.3390/inventions8060155
Elena Dobychina, M. Snastin, Vladimir Savchenko, T. Shevgunov
In this paper, we will discuss a calibration algorithm for a digital antenna array that diagnoses its real performance. It can be applied at such stages of the antenna system life cycle as design, tuning, and especially maintenance. A calibration implementation using a scalar method for a multi-beam digital antenna array is proposed and investigated. On-the-fly calibration ensures a continuous improvement in beam pointing accuracy by reducing internal errors in the receiving (transmitting) channels. The purpose of the study is to experimentally examine the capabilities of digital beamforming to increase the angle-of-arrival estimation accuracy. A simulation model of the receiving antenna was created in an anechoic chamber with a planar antenna positioner. The possibility of precise estimation of the direction of arrival using the digital beamforming with electronic scanning was demonstrated. The proposed simulation model made it possible to observe the convergence of the antenna array calibration process using the proposed method for various errors in the signal paths, as well as different signal-to-noise ratios. It has been proven that even under adverse conditions early in the calibration algorithm, the phase error detection converges with high accuracy, and its value decreases uniformly even to the fractions of an angular degree.
{"title":"Development of the Phaseless Calibration Algorithm for a Digital Antenna Array","authors":"Elena Dobychina, M. Snastin, Vladimir Savchenko, T. Shevgunov","doi":"10.3390/inventions8060155","DOIUrl":"https://doi.org/10.3390/inventions8060155","url":null,"abstract":"In this paper, we will discuss a calibration algorithm for a digital antenna array that diagnoses its real performance. It can be applied at such stages of the antenna system life cycle as design, tuning, and especially maintenance. A calibration implementation using a scalar method for a multi-beam digital antenna array is proposed and investigated. On-the-fly calibration ensures a continuous improvement in beam pointing accuracy by reducing internal errors in the receiving (transmitting) channels. The purpose of the study is to experimentally examine the capabilities of digital beamforming to increase the angle-of-arrival estimation accuracy. A simulation model of the receiving antenna was created in an anechoic chamber with a planar antenna positioner. The possibility of precise estimation of the direction of arrival using the digital beamforming with electronic scanning was demonstrated. The proposed simulation model made it possible to observe the convergence of the antenna array calibration process using the proposed method for various errors in the signal paths, as well as different signal-to-noise ratios. It has been proven that even under adverse conditions early in the calibration algorithm, the phase error detection converges with high accuracy, and its value decreases uniformly even to the fractions of an angular degree.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"19 8","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138979999","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 : 2023-12-08DOI: 10.3390/inventions8060154
V. León-Martínez, E. Peñalvo-López, Clara Andrada-Monrós, Juan Ángel Sáiz-Jiménez
Load losses determine transformers’ efficiency and life, which are limited by overheating and deterioration of their elements. Since these losses can be characterized by short-circuit resistances, in this article, we have developed expressions for the short-circuit resistances of three-phase transformers according to IEEE Standard C57.110. Imposing the condition that these resistances must cause load losses of the transformer, two types of short-circuit resistance have been established: (1) the effective resistance of each phase (Rcc,z) and (2) the effective short-circuit resistance of the transformer (Rcc,ef). The first is closely related to the power loss distribution within the transformer. The second is just a mathematical parameter. Applying these resistances to the 630 kVA oil-immersed distribution transformer of a residential network, we have concluded that both types of resistances determine the total load losses of the transformer. However, only Rcc,z accurately provides the load losses in each phase. Rcc,ef can give rise to errors more significant than 16% in calculating these losses, depending on imbalances in the harmonic currents.
{"title":"Load Losses and Short-Circuit Resistances of Distribution Transformers According to IEEE Standard C57.110","authors":"V. León-Martínez, E. Peñalvo-López, Clara Andrada-Monrós, Juan Ángel Sáiz-Jiménez","doi":"10.3390/inventions8060154","DOIUrl":"https://doi.org/10.3390/inventions8060154","url":null,"abstract":"Load losses determine transformers’ efficiency and life, which are limited by overheating and deterioration of their elements. Since these losses can be characterized by short-circuit resistances, in this article, we have developed expressions for the short-circuit resistances of three-phase transformers according to IEEE Standard C57.110. Imposing the condition that these resistances must cause load losses of the transformer, two types of short-circuit resistance have been established: (1) the effective resistance of each phase (Rcc,z) and (2) the effective short-circuit resistance of the transformer (Rcc,ef). The first is closely related to the power loss distribution within the transformer. The second is just a mathematical parameter. Applying these resistances to the 630 kVA oil-immersed distribution transformer of a residential network, we have concluded that both types of resistances determine the total load losses of the transformer. However, only Rcc,z accurately provides the load losses in each phase. Rcc,ef can give rise to errors more significant than 16% in calculating these losses, depending on imbalances in the harmonic currents.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"6 2","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139011546","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 : 2023-12-06DOI: 10.3390/inventions8060153
Cao Thang Luong, Ali Farhan, Ross D. Vasquez, M. J. Roldan, Yih-Kai Lin, Shih-Yen Hsu, Ming-Der Lin, Chung-Der Hsiao, Chih-Hsin Hung
Accurate and rapid taxonomy identification is the initial step in spider image recognition. More than 50,000 spider species are estimated to exist worldwide; however, their identification is still challenging due to the morphological similarity in their physical structures. Deep learning is a known modern technique in computer science, biomedical science, and bioinformatics. With the help of deep learning, new opportunities are available to reveal advanced taxonomic methods. In this study, we applied a deep-learning-based approach using the YOLOv7 framework to provide an efficient and user-friendly identification tool for spider species found in Taiwan called Spider Identification APP (SpiderID_APP). The YOLOv7 model is integrated as a fully connected neural network. The training of the model was performed on 24,000 images retrieved from the freely available annotated database iNaturalist. We provided 120 genus classifications for Taiwan spider species, and the results exhibited accuracy on par with iNaturalist. Furthermore, the presented SpiderID_APP is time- and cost-effective, and researchers and citizen scientists can use this APP as an initial entry point to perform spider identification in Taiwan. However, for detailed species identification at the species level, additional methods like DNA barcoding or genitalic structure dissection are still considered necessary.
{"title":"SpiderID_APP: A User-Friendly APP for Spider Identification in Taiwan Using YOLO-Based Deep Learning Models","authors":"Cao Thang Luong, Ali Farhan, Ross D. Vasquez, M. J. Roldan, Yih-Kai Lin, Shih-Yen Hsu, Ming-Der Lin, Chung-Der Hsiao, Chih-Hsin Hung","doi":"10.3390/inventions8060153","DOIUrl":"https://doi.org/10.3390/inventions8060153","url":null,"abstract":"Accurate and rapid taxonomy identification is the initial step in spider image recognition. More than 50,000 spider species are estimated to exist worldwide; however, their identification is still challenging due to the morphological similarity in their physical structures. Deep learning is a known modern technique in computer science, biomedical science, and bioinformatics. With the help of deep learning, new opportunities are available to reveal advanced taxonomic methods. In this study, we applied a deep-learning-based approach using the YOLOv7 framework to provide an efficient and user-friendly identification tool for spider species found in Taiwan called Spider Identification APP (SpiderID_APP). The YOLOv7 model is integrated as a fully connected neural network. The training of the model was performed on 24,000 images retrieved from the freely available annotated database iNaturalist. We provided 120 genus classifications for Taiwan spider species, and the results exhibited accuracy on par with iNaturalist. Furthermore, the presented SpiderID_APP is time- and cost-effective, and researchers and citizen scientists can use this APP as an initial entry point to perform spider identification in Taiwan. However, for detailed species identification at the species level, additional methods like DNA barcoding or genitalic structure dissection are still considered necessary.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"60 2","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138597311","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}
The sparse atmosphere on the surface of Mars provides the necessary flight conditions for Mars unmanned aerial vehicles (UAVs) to perform low-altitude flights. This work presents a comprehensive overview of key technologies in the development of Mars UAVs, with a specific focus on rotary-wing Mars UAVs. It summarizes prototypes of rotary-wing Mars UAVs developed by various global research institutions. It reviews essential technologies in rotary-wing Mars UAV research, including the Mars near-surface atmospheric environment, aerodynamic characteristics, and principles of low-pressure flight control. This work also summarizes various experimental setups and ground test results for rotary-wing Mars UAVs. Furthermore, it discusses the future development trends of rotary-wing Mars UAVs.
{"title":"Review of Key Technologies of Rotary-Wing Mars UAVs for Mars Exploration","authors":"Pengyue Zhao, Ruihan Li, Peng Wu, Huan Liu, Xifeng Gao, Zongquan Deng","doi":"10.3390/inventions8060151","DOIUrl":"https://doi.org/10.3390/inventions8060151","url":null,"abstract":"The sparse atmosphere on the surface of Mars provides the necessary flight conditions for Mars unmanned aerial vehicles (UAVs) to perform low-altitude flights. This work presents a comprehensive overview of key technologies in the development of Mars UAVs, with a specific focus on rotary-wing Mars UAVs. It summarizes prototypes of rotary-wing Mars UAVs developed by various global research institutions. It reviews essential technologies in rotary-wing Mars UAV research, including the Mars near-surface atmospheric environment, aerodynamic characteristics, and principles of low-pressure flight control. This work also summarizes various experimental setups and ground test results for rotary-wing Mars UAVs. Furthermore, it discusses the future development trends of rotary-wing Mars UAVs.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"29 32","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139213855","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 : 2023-11-29DOI: 10.3390/inventions8060152
D. Dehay, J. Leśkow, Antonio Napolitano, T. Shevgunov
The signal detection problem for cyclostationary signals is addressed within the fraction-of-time probability framework, where statistical functions are constructed starting from a single time series, without introducing the concept of stochastic process. Single-cycle detectors and quadratic-form detectors based on measurements of the Fourier coefficients of the almost-periodically time-variant cumulative distribution and probability density functions are proposed. The adopted fraction-of-time approach provides both methodological and implementation advantages for the proposed detectors. For single-cycle detectors, the decision statistic is a function of the received signal and the threshold is derived using side data under the null hypothesis. For quadratic-form detectors, the decision statistic can be expressed as a function of the received signal without using side data, at the cost of some performance degradation. The threshold can be derived analytically. Performance analysis is carried out using Monte Carlo simulations in severe noise and interference environments, where the proposed detectors provide better performance with respect to the analogous detectors based on second- and higher-order cyclic statistic measurements.
{"title":"Cyclic Detectors in the Fraction-of-Time Probability Framework","authors":"D. Dehay, J. Leśkow, Antonio Napolitano, T. Shevgunov","doi":"10.3390/inventions8060152","DOIUrl":"https://doi.org/10.3390/inventions8060152","url":null,"abstract":"The signal detection problem for cyclostationary signals is addressed within the fraction-of-time probability framework, where statistical functions are constructed starting from a single time series, without introducing the concept of stochastic process. Single-cycle detectors and quadratic-form detectors based on measurements of the Fourier coefficients of the almost-periodically time-variant cumulative distribution and probability density functions are proposed. The adopted fraction-of-time approach provides both methodological and implementation advantages for the proposed detectors. For single-cycle detectors, the decision statistic is a function of the received signal and the threshold is derived using side data under the null hypothesis. For quadratic-form detectors, the decision statistic can be expressed as a function of the received signal without using side data, at the cost of some performance degradation. The threshold can be derived analytically. Performance analysis is carried out using Monte Carlo simulations in severe noise and interference environments, where the proposed detectors provide better performance with respect to the analogous detectors based on second- and higher-order cyclic statistic measurements.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"113 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139213166","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 : 2023-11-22DOI: 10.3390/inventions8060150
Amalia Moutsopoulou, M. Petousis, N. Vidakis, G. Stavroulakis, A. Pouliezos
In this paper, our strategy is to look for locally optimum answers to a non-smooth optimization problem that has been constructed to include minimization goals and restrictions for smart structures’ vibration suppression. In both theoretical analysis and practical implementation, it is widely recognized that designing multi-objective control systems poses a considerable challenge. In this study, we assess the effectiveness of this method by employing the open-source Matlab toolbox Hifoo 2.0 and juxtapose our findings with established industry standards. We start by framing the control problem as a mathematical optimization issue and proceed to identify the controller that effectively addresses this optimization. This approach introduces the potential application of intelligent structures in tackling the challenge of vibration suppression. This study makes use of the most recent version of the freely available application Hifoo which tries to study vibration suppression with the limits outlined above in the context of multi-objective controller design. A controller directive is initially set, allowing for a lower order.
{"title":"Applications of the Order Reduction Optimization of the H-Infinity Controller in Smart Structures","authors":"Amalia Moutsopoulou, M. Petousis, N. Vidakis, G. Stavroulakis, A. Pouliezos","doi":"10.3390/inventions8060150","DOIUrl":"https://doi.org/10.3390/inventions8060150","url":null,"abstract":"In this paper, our strategy is to look for locally optimum answers to a non-smooth optimization problem that has been constructed to include minimization goals and restrictions for smart structures’ vibration suppression. In both theoretical analysis and practical implementation, it is widely recognized that designing multi-objective control systems poses a considerable challenge. In this study, we assess the effectiveness of this method by employing the open-source Matlab toolbox Hifoo 2.0 and juxtapose our findings with established industry standards. We start by framing the control problem as a mathematical optimization issue and proceed to identify the controller that effectively addresses this optimization. This approach introduces the potential application of intelligent structures in tackling the challenge of vibration suppression. This study makes use of the most recent version of the freely available application Hifoo which tries to study vibration suppression with the limits outlined above in the context of multi-objective controller design. A controller directive is initially set, allowing for a lower order.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"200 ","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139249730","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 : 2023-11-19DOI: 10.3390/inventions8060149
R. Bridgelall
The gradual adoption of electric vehicles (EVs) globally serves as a crucial move toward addressing global decarbonization goals for sustainable development. However, the lack of cost-effective, power-efficient, and safe chargers for EV batteries hampers adoption. Understanding the research needs and identifying the gaps in EV charger innovation informs investments and research to address development challenges. This study developed a unique text mining workflow to classify themes in EV charger technology and product development by analyzing U.S. patent award summaries. The text mining workflow combined the techniques of data extraction, data cleaning, natural language processing (NLP), statistical analysis, and unsupervised machine learning (ML) to extract unique themes and to visualize their relationships. There was a 47.7% increase in the number of EV charger patents issued in 2022 relative to that in 2018. The top four themes were charging station management, power transfer efficiency, on-board charger design, and temperature management. More than half (53.8%) of the EV charger patents issued over the five-year period from 2018 to 2022 addressed problems within those four themes. Patents that addressed wireless charging, fast charging, and fleet charging accounted for less than 10% each of the EV charger patents issued. This suggests that the industry is still at the frontier of addressing those problems. This study further presents examples of the specific EV charger problems addressed within each theme. The findings can inform investment decisions and policymaking to focus on R&D resources that will advance the state of the art and spur EV adoption.
{"title":"Classifying Invention Objectives of Electric Vehicle Chargers through Natural Language Processing and Machine Learning","authors":"R. Bridgelall","doi":"10.3390/inventions8060149","DOIUrl":"https://doi.org/10.3390/inventions8060149","url":null,"abstract":"The gradual adoption of electric vehicles (EVs) globally serves as a crucial move toward addressing global decarbonization goals for sustainable development. However, the lack of cost-effective, power-efficient, and safe chargers for EV batteries hampers adoption. Understanding the research needs and identifying the gaps in EV charger innovation informs investments and research to address development challenges. This study developed a unique text mining workflow to classify themes in EV charger technology and product development by analyzing U.S. patent award summaries. The text mining workflow combined the techniques of data extraction, data cleaning, natural language processing (NLP), statistical analysis, and unsupervised machine learning (ML) to extract unique themes and to visualize their relationships. There was a 47.7% increase in the number of EV charger patents issued in 2022 relative to that in 2018. The top four themes were charging station management, power transfer efficiency, on-board charger design, and temperature management. More than half (53.8%) of the EV charger patents issued over the five-year period from 2018 to 2022 addressed problems within those four themes. Patents that addressed wireless charging, fast charging, and fleet charging accounted for less than 10% each of the EV charger patents issued. This suggests that the industry is still at the frontier of addressing those problems. This study further presents examples of the specific EV charger problems addressed within each theme. The findings can inform investment decisions and policymaking to focus on R&D resources that will advance the state of the art and spur EV adoption.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"66 2","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139260034","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 : 2023-11-17DOI: 10.3390/inventions8060148
Alexey Savitskii, D. Sharaborin, L. Chikishev, V. Dulin
Swirling flows often occur in nature and industrial applications. With an increase in swirl intensity, such rotating flows are known to become unstable and undergo a sudden breakdown of the vortex core, resulting in unsteady flow dynamics with intensive pressure fluctuations. In particular, swirling flows are organized in combustion chambers to stabilize the flame around the central recirculation zone, formed due to the vortex core breakdown. However, the impact of large-scale vortex structures, including the precessing vortex core and secondary helical vortices, on unsteady combustion regimes is still unclear. The present paper demonstrates experimentally that for the swirling flow of a model swirl combustor, the injection of a central jet may be used to alter the configuration of coherent flow structures, including helical vortices. In particular, the asymmetric hydrodynamics mode, associated with the precessing vortex core, is suppressed, whereas the symmetrical one becomes dominant. This effect demonstrates the importance of central jet injection to control the dominant mode of flow instability for the design of swirl combustors.
{"title":"Flow Instability Control in a Model Swirl-Stabilized Combustor with Central Jet Injection","authors":"Alexey Savitskii, D. Sharaborin, L. Chikishev, V. Dulin","doi":"10.3390/inventions8060148","DOIUrl":"https://doi.org/10.3390/inventions8060148","url":null,"abstract":"Swirling flows often occur in nature and industrial applications. With an increase in swirl intensity, such rotating flows are known to become unstable and undergo a sudden breakdown of the vortex core, resulting in unsteady flow dynamics with intensive pressure fluctuations. In particular, swirling flows are organized in combustion chambers to stabilize the flame around the central recirculation zone, formed due to the vortex core breakdown. However, the impact of large-scale vortex structures, including the precessing vortex core and secondary helical vortices, on unsteady combustion regimes is still unclear. The present paper demonstrates experimentally that for the swirling flow of a model swirl combustor, the injection of a central jet may be used to alter the configuration of coherent flow structures, including helical vortices. In particular, the asymmetric hydrodynamics mode, associated with the precessing vortex core, is suppressed, whereas the symmetrical one becomes dominant. This effect demonstrates the importance of central jet injection to control the dominant mode of flow instability for the design of swirl combustors.","PeriodicalId":14564,"journal":{"name":"Inventions","volume":"2 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139265930","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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