AIP Advances最新文献

{"title":"Lunar heat flow from the observation of Chinese Chang’E 2 and LRO diviner radiometers","authors":"Dan Zhang, Cui Li","doi":"10.1063/5.0221307","DOIUrl":"https://doi.org/10.1063/5.0221307","url":null,"abstract":"Lunar heat flow within 75°N to 65°S and 60°W to 100°E regions is retrieved from microwave brightness temperature observed by Chang’E-2 (CE-2) Lunar Microwave Radiometers and infrared brightness temperature observed by Lunar Reconnaissance Orbiter (LRO) Diviner Radiometers. The product of the regolith’s thermal conductivity and vertical temperature gradient yields the lunar heat flow. The vertical temperature gradient is calculated by a new temperature profile, the unknown parameters of which are determined from CE-2 microwave brightness temperature using a multi-layered lunar surface microwave brightness temperature model. The boundary condition of the temperature profile is determined by the LRO infrared brightness temperature. The measured heat flow at the Apollo 15 landing site is chosen as a calibration reference point in the retrieval process. The retrieved lunar heat flow within 75°N to 65°S and 60°W to 100°E regions ranged from 0.8 to 69.2 mW/m2. According to the retrieved results, lunar heat flow in the highlands is higher than the maria. The highest heat flux within 75°N to 65°S and 60°W to 100°E regions on the Moon are located toward the eastern highlands with an averaged heat flow value of 35.8 mW/m2, and the lowest heat flux is basically located in the typical maria such as Oceans Procellarum, Mare Imbrium, and Mare Serenitatis with an averaged heat flow value of 18.5 mW/m2.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical analysis of thermal performance of various types of horizontal ground heat exchangers","authors":"Nushrat Jahan, Md Hasan Ali, Akio Miyara","doi":"10.1063/5.0217003","DOIUrl":"https://doi.org/10.1063/5.0217003","url":null,"abstract":"In this paper, three types of horizontal ground heat exchangers (GHEs) such as U-tube, spiral, and slinky were numerically analyzed to investigate their thermal performance in cooling mode for 7 days of continuous operation with specific boundary conditions where a rectangular trench of 5 m in length, 2 m in width, and 5 m in depth served as the basis for the modeling of each heat exchanger. The pipe material was selected to be high density polyethylene for higher durability and corrosion resistance, as well as the soil and working fluid, which were clay and water. To confirm the accuracy of simulation results and reduce the computational time, a mesh independence test was performed, and simulation models were validated. There were four types of modifications, and in all of the cases, slinky GHE has better thermal performance. For instance, the heat exchange rate per unit trench length of slinky GHE was 20.72 W/m, which is higher than U-tube and spiral tube with a heat exchange rate of 9.75 and 13.62 W/m, which is of maximum 53% and 28% than U tube GHE, respectively, for the same pipe wall thickness and different material volumes of U-tube, spiral, and slinky GHEs. The pressure drop of slinky GHE is also higher (maximum 87% higher than U tube). To balance the heat exchange rate and pressure drop, the thermal performance capability (TPC) was examined. The slinky GHE has the highest thermal performance capability for all the cases. From the energy balance point, the TPC valued a maximum of 1.72 for the same material volume and different pipe wall thickness. The effectiveness was investigated to examine the heat exchange rate with different ground temperatures, and the slinky GHE showed higher effectiveness than spiral and U-tube GHEs. Finally, the thermal performance of slinky horizontal GHE was examined with different trench lengths to investigate the excavation work reduction with reduced trench length. With the decrease in trench length, the heat exchange rate and excavation work also decreased. The heat exchange rate of slinky horizontal GHEs with trench lengths of 1.5 and 1 m remained better than that of spiral and U-tube horizontal GHEs with a trench length of 3.5 m.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new method for short-term photovoltaic power generation forecast based on ensemble model","authors":"Yunxiu Zhang, Bingxian Li, Zhiyin Han","doi":"10.1063/5.0226761","DOIUrl":"https://doi.org/10.1063/5.0226761","url":null,"abstract":"Photovoltaic (PV) power generation is influenced by various factors, including weather conditions, the quality of PV inverters, and the cleanliness of PV modules, with weather conditions having a particularly significant impact on power output. This paper proposes a novel method for PV power generation prediction based on an ensemble forecasting model, aimed at constructing an efficient and stable PV prediction model. Initially, Z-score is employed to filter outliers in the PV data, and Robust STL–bilinear temporal–spectral fusion is introduced for time series feature extraction. Subsequently, an ensemble forecasting model based on bidirectional long short-term memory and extreme gradient boosting is proposed to address the limitations of existing predictive models, which suffer from low robustness and an inability to provide stable forecasts. Furthermore, to mitigate the performance degradation of the prediction model due to manual tuning, a tactics enhanced white shark optimizer is proposed for parameter optimization of the ensemble model. The optimization performance is validated using the IEEE CEC2021 test functions. Finally, the proposed method is tested on PV power generation data from a site in Shandong, China. The results demonstrate that the proposed ensemble forecasting method achieves high accuracy and exhibits strong model stability.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design, simulation, and experimental validation of a wideband flexible metamaterial absorber for gigahertz electromagnetic waves","authors":"Ghada Fatima Zahra Mebarki, Naima Benmostefa, Mohammed Feham, Mohammed Ayad Alkhafaji, Serge Dzo Mawuefa Afenyiveh, Younes Menni","doi":"10.1063/5.0229586","DOIUrl":"https://doi.org/10.1063/5.0229586","url":null,"abstract":"This study addresses the challenge of mitigating electromagnetic interference (EMI) in telecommunications and radar systems by designing, simulating, and experimentally validating a wideband flexible metamaterial absorber (MMA) for gigahertz-frequency electromagnetic waves (EMWs). EMI is critical as it can severely impact the performance and reliability of electronic systems. Traditional absorbers often struggle to maintain high performance across a broad frequency range, especially under varying polarization and incidence angles. To address this issue, we developed a novel MMA with a simple, single-layer design optimized for wideband absorption over a 10 GHz frequency range. Constructed with a polyethylene terephthalate dielectric layer separating spiral coil resonators from a bottom copper layer, this configuration ensures polarization insensitivity for both transverse electric and transverse magnetic waves. Numerical simulations were used to optimize the design parameters, focusing on maximizing absorption efficiency across the targeted frequency range and varying incidence angles. Experimental validation was conducted to verify the absorber’s performance, with results showing excellent agreement with simulations. This research underscores the importance of experimental verification in validating the performance of MMAs and highlights their potential for real-world applications in absorbing EMWs.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"OpenLabSPM: Bare bone package of LabVIEW-based scanning probe microscope controller","authors":"Hikaru Nomura, Junsuke Yamanishi","doi":"10.1063/5.0211126","DOIUrl":"https://doi.org/10.1063/5.0211126","url":null,"abstract":"With the extensive proliferation of scanning probe microscopy (SPM)-related technologies, there is a growing demand for a fully customizable SPM controller. In response, we have developed an SPM controller that allows users to incorporate additional functions using LabVIEW, a graphical programming language. This controller incorporates fundamental features such as one-dimensional and two-dimensional scanning, feedback control, and slope compensation. In addition, it includes capabilities to restrict the speed of probe movement and safeguard the probe. Our system consists of a host personal computer (PC) running the Windows operating system and a National Instruments Reconfigurable Input/Output board equipped with a field programmable gate array (FPGA). The FPGA supports real-time deterministic processing, including feedback and probe protection functions, operating asynchronously from the host PC through data exchange via direct memory access first-in-first-out. The system features a graphical user interface on the Windows OS, supplemented by a character-based user interface that utilizes command strings in JavaScript object notation format. Furthermore, we provide wrappers for these commands using the Python programming language. We anticipate that our fully customizable bare born package of LabVIEW-based controller will prove beneficial for researchers utilizing SPM and those managing instruments requiring scanning and feedback control.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrically insulating thermal interface material with ultrahigh thermal conductivity enabled by vertical boron nitride fibers","authors":"Haoran Yang, Yisimayili Tuersun, Pingjun Luo, Yixin Chen, Xu Huang, Qi Huang, Xuechen Chen, Sheng Chu","doi":"10.1063/5.0207569","DOIUrl":"https://doi.org/10.1063/5.0207569","url":null,"abstract":"With the increasing integration levels of modern electronic products, effective thermal management has become a critical concern to ensure the operational efficiency and longevity of electronic devices. Developing thermal interface materials that possess both high thermal conductivity (κ) and reliable insulation properties has presented a significant challenge. In this study, boron nitride fibers (BNF) with a substantial length-to-diameter ratio were fabricated to serve as vertically aligned thermal conduction channels within a composite pad containing a silicone gel matrix.Under typical packing pressure conditions, the resulting BNF pad exhibits an exceptionally high through-plane thermal conductivity (40 vol. %: κ⊥ = 16.77 W/mK). Additionally, the BNF pad demonstrates favorable mechanical and dielectric properties, enhancing its versatility and applicability. The results of actual heat dissipation tests further validate the excellent thermal management capabilities of these composites in high-power electronic applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of stagnation point heat transfer with MHD effects using finite difference method: Analysis of thermal absorption and generation","authors":"Sadia Irshad, Shah Jahan, Afraz Hussain Majeed, Ehab Ghith, Mehdi Tlija, Atif Asghar, Nusrat Rehman","doi":"10.1063/5.0219843","DOIUrl":"https://doi.org/10.1063/5.0219843","url":null,"abstract":"The objective of this research endeavor is to examine the properties of stagnation point flow in the presence of absorption, viscous dissipation, and internal thermal generation with respect to a shrinking surface. The resulting system of differential equations is notoriously challenging to solve analytically. The equations controlling the boundary layer flow were solved using a finite difference method. The analysis includes the examination of important physical quantities through the presentation of plots and tabulated values. Our findings reveal a strong connection between the presence of solutions for high shrinking parameters and the magnetic field that was applied. Temperatures increase when there is an increase in both Ec and α at the same time. These results also suggest a shallowing of the thermal boundary layer. As a result of these findings, it appears that temperature and thermal boundary layer thickness are sensitive to changes in these factors.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Segmentation of lung nodules in CT images using weighted average based threshold and maximized variance","authors":"Yankun Liu, Tong Zhang, Ma Liang, Enguo Wang","doi":"10.1063/5.0216374","DOIUrl":"https://doi.org/10.1063/5.0216374","url":null,"abstract":"Background: Lung cancer is a major health concern globally, being the primary cause of cancer-related deaths. It accounts for approximately one–sixth of all cancer fatalities. Objective: The goal of this study is to develop an effective method for the early detection of lung tumors using computed tomography (CT) images. This method aims to identify lung tumors of various sizes and shapes, which is a significant challenge due to the variability in tumor characteristics. Methods: The research utilizes CT images of the lungs in sagittal view from the LID-IDRI database. To tackle the issue of tumor variability in size, shape, and number, the study proposes a novel image processing technique. This technique involves detecting tumor clusters using a weighted average-based automatic thresholding method. This method focuses on maximizing inter-class variance and is supplemented by further classification and segmentation processes. Results: The proposed image processing technique was tested on a dataset of 315 lung CT images. It demonstrated a high level of accuracy, achieving a 98.96% success rate in identifying lung tumors. Conclusion: The study introduces a highly effective method for the detection of lung tumors in CT images, irrespective of their size and shape. The technique’s high accuracy rate suggests it could be a valuable tool in the early diagnosis of lung cancer, potentially leading to improved patient outcomes.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A self-sustaining wireless sensing and flight control device for beetles","authors":"Xin Huang, Wenhao Zhao, Meisong Yuan, Kaixuan Sun, Bo Yang","doi":"10.1063/5.0228102","DOIUrl":"https://doi.org/10.1063/5.0228102","url":null,"abstract":"Insect-electronics hybrid robots integrate live insects with small electronic backpacks. These backpacks guide insect movement and sense environmental data. Due to size and payload constraints, high-capacity batteries are impractical for prolonged energy supply. This study proposes a self-sustaining wireless sensing and flight control device with an energy management module and a Bluetooth slave module. This setup enables solar energy harvesting, wireless flight control of beetles, and the acquisition of image and attitude information. The device achieves directional flight control with a 72.5% success rate in turning. Operation duration increases by 46.6% in image-only mode and 50.9% in combined image and attitude angle mode under 20 000 lux indoor illuminance. Outdoor experiments demonstrate continuous operation at one image per second under favorable illuminance conditions, with a 92% increase in operation time when capturing images and yaw angles. This microelectronic device enhances the durability of insect robots during extended field missions, providing valuable insights into long-term environmental monitoring.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A three-point velocity estimation method for two-dimensional coarse-grained imaging data","authors":"J. M. Losada, A. D. Helgeland, J. L. Terry, O. E. Garcia","doi":"10.1063/5.0197251","DOIUrl":"https://doi.org/10.1063/5.0197251","url":null,"abstract":"Time delay and velocity estimation methods have been widely studied subjects in the context of signal processing, with applications in many different fields of physics. The velocity of waves or coherent fluctuation structures is commonly estimated as the distance between two measurement points divided by the time lag that maximizes the cross correlation function between the measured signals, but this is demonstrated to result in erroneous estimates for two spatial dimensions. We present an improved method to accurately estimate both components of the velocity vector, relying on three non-aligned measurement points. We introduce a stochastic process describing the fluctuations as a superposition of uncorrelated pulses moving in two dimensions. Using this model, we show that the three-point velocity estimation method, using time delays calculated through cross correlations, yields the exact velocity components when all pulses have the same velocity. The two- and three-point methods are tested on synthetic data generated from realizations of such processes for which the underlying velocity components are known. The results reveal the superiority of the three-point technique. Finally, we demonstrate the applicability of the velocity estimation on gas puff imaging data of strongly intermittent plasma fluctuations due to the radial motion of coherent, blob-like structures at the boundary of the Alcator C-Mod tokamak.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}