bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance evaluation of a mechanical ventilation simulation model for diverse respiratory complications
Authors: Mahatme Chetan , Giri Jayant , Al-Lohedan Hamad A. , Mohammad Faruq , Sunheriya Neeraj , Chadge Rajkumar , T. Sathish , Giri Pallavi , Mallik Saurav , Dhayalan Manikandan
Published: March 2024

Medical life-saving techniques include mechanical ventilation. During the COVID-19 epidemic, the lack of inexpensive, precise, and accessible mechanical ventilation equipment was the biggest challenge. The global need exploded, especially in developing nations. Global researchers and engineers are developing inexpensive, portable medical ventilators. A simpler mechanical ventilator system with a realistic lungs model is simulated in this work. A systematic ventilation study is done using the dynamic simulation of the model. Simulation findings of various medical disorders are compared to standard data. The maximum lung pressure (Pmax) was 15.78 cmH2O for healthy lungs, 17.72 for cardiogenic pulmonary edema, 16.05 for pneumonia, 19.74 for acute respiratory distress syndrome (ARDS), 17.1 for AECOPD, 19.64 for asthma, and 15.09 for acute intracranial illnesses and head traumas. All were below 30 cmH2O, the average maximum pressure. The computed maximum tidal volume (TDVmax) is 0.5849 l, substantially lower than that of the healthy lungs (0.700 l). The pneumonia measurement was 0.4256 l, substantially lower than the typical 0.798 l. TDVmax was 0.3333 l for ARDS, lower than the usual 0.497 l. The computed TDVmax for AECOPD was 0.6084 l, lower than the normal 0.700 l. Asthma had a TDVmax of 0.4729 l, lower than the typical 0.798 l. In individuals with acute cerebral diseases and head traumas, TDVmax is 0.3511 l, lower than the typical 0.700 l. The results show the viability of the model as it performs accurately to the presented medical condition parameters. Further clinical trials are needed to assess the safety and reliability of the simulation model.
Thermal atomic layer deposition of aluminum oxide, nitride, and oxynitride: A mechanistic investigation
Authors: Aqueel Ahmed Abu Talha , Hafiyyan Afina faza , Nurhidayati Nurhidayati , Hidayah Rayanisaputri Fani Rahayu , Alibrahim Khuloud A. , Khadtare Shubhangi S. , Rahman Shofiur , Alodhayb Abdullah N. , Rochman Nurul Taufiqu , Ansari Abu Saad
Published: March 2024

Atomic layer deposition (ALD) has been proven to be a versatile method for the deposition of thin films of various materials. It yields films with exceptional conformality and allows tunable film compositions with control of film thickness at the atomic level. Thin films of Al oxide, nitride, and oxynitride are deposited via ALD using Al(CH3)3 (TMA)/AlCl3 with H2O/NH3. Herein, surface chemical reactions are examined using density functional theory calculations to elucidate the adsorption, oxidation, and nitridation of precursors [TMA and AlCl3] as well as the mechanism controlling the composition of Al oxynitride thin films obtained through ALD. The hydrogen-terminated substrate surface is transformed into a CH3/Cl-terminated surface after the reaction with the TMA/AlCl3 precursors. The molecular adsorption of TMA occurs through a spontaneous reaction, whereas that of AlCl3 requires a slight energy input. Although the adsorption energy of AlCl3 is higher than that of TMA, the activation energy and energy change of AlCl3 adsorption are higher and lower than those of TMA, respectively; furthermore, the use of AlCl3 results in the generation of a corrosive by-product (HCl). A similar tendency is observed in the second ALD half reaction, which is oxidation. Nitride formation is endothermic for molecularly adsorbed AlCl3 but exothermic for TMA. Furthermore, the investigation of the exchange reactions between surface moieties and excess gaseous reactants reveals a preference for the substitution of N by O, which is attributed to differences in bond energies between the surface moieties and the surface metal atom, as well as between H2O and NH3.
Magnetic functionalization and catalytic behavior of magnetic nanoparticles during laser photochemical graphitization of polyimide
Authors: Sarkar Abhishek , Noh Ho-won , Nlebedim Ikenna C. , Shrotriya Pranav
Published: March 2024

We report laser-assisted photochemical graphitization of polyimides (PIs) into functional magnetic nanocomposites using laser irradiation of PI in the presence of magnetite nanoparticles (MNPs). PI Kapton sheets covered with MNP were photochemically treated under ambient conditions using a picosecond pulsed laser (1064 nm) to obtain an electrically conductive material. Scanning electron microscopy of the treated material revealed a layered magnetic nanoparticle/graphite (MNP/graphite) nanocomposite structure. Four probe conductivity measurements indicated that the nanocomposite has an electrical conductivity of 1550 ± 60 S/m. Superconducting quantum interference device magnetometer-based magnetic characterization of the treated material revealed an anisotropic ferromagnetic response in the MNP/graphite nanocomposite compared to the isotropic response of MNP. Raman spectroscopy of the MNP/graphite nanocomposite revealed a fourfold improvement in graphitization, suppression in disorder, and decreased nitrogenous impurities compared to the graphitic material obtained from laser treatment of just PI sheets. X-ray photoelectron spectroscopy, x-ray diffraction, and energy-dispersive x-ray spectroscopy were used to delineate the phase transformations of MNP during the formation of MNP/graphite nanocomposite. Post-mortem characterization indicates a possible photocatalytic effect of MNP during MNP/graphite nanocomposite formation. Under laser irradiation, MNP transformed from the initial Fe3O4 phase to γ-Fe2O3 and Fe5C2 phases and acted as nucleation spots to catalyze the graphitization process of PI.
Enhancement of local anti-demagnetization ability of permanent magnet by selected area grain boundary diffusion toward high-speed motors
Authors: Li Weizhou , Cheng Jungang , Lu Xusheng , Li Yangyang , Zhao Dong , Pei Wenli , Pei Ruilin
Published: March 2024

The working environment of permanent magnets in high-speed motors is harsh, because they are seriously affected by multi-physical fields such as temperature, stress, weak magnetic control field, etc., and irreversible demagnetization is easy to occur under the extreme working conditions. In this work, a model of high-speed Interior Permanent magnet Motor is established, the easy demagnetization area of the permanent magnet is simulated by electromagnetic and thermal simulations to determine, and its local anti-demagnetization optimization is performed. Dy/Tb co-infiltration is carried out in the easy demagnetization region of the permanent magnets, and the process of selective zone diffusion is analyzed based on the principle of selective zone grain boundary diffusion. Through microscopic observation and macroscopic magnetic performance test, the effect of local anti-demagnetization performance enhancement of the optimized permanent magnets is verified. The results show that the magnetic properties of the optimized permanent magnets are obviously improved after the optimization of the selected zones. The present approach is important for the follow-up less heavy-rare-earth research of permanent magnet and its application in high-speed motors.
Better batteries for cold weather
Authors: Fattaruso Laura
Published: March 2024

A solvent with small molecules forms channels that increase the speed of lithium-ion transport, even at low temperatures.
Photo-neuro-immuno-endocrinology: How the ultraviolet radiation regulates the body, brain, and immune system
Authors: Slominski Radomir M. , Chen Jake Y. , Raman Chander , Slominski Andrzej T.
Published: March 2024

Ultraviolet radiation (UVR) is primarily recognized for its detrimental effects such as cancerogenesis, skin aging, eye damage, and autoimmune disorders. With exception of ultraviolet B (UVB) requirement in the production of vitamin D3, the positive role of UVR in modulation of homeostasis is underappreciated. Skin exposure to UVR triggers local responses secondary to the induction of chemical, hormonal, immune, and neural signals that are defined by the chromophores and extent of UVR penetration into skin compartments. These responses are not random and are coordinated by the cutaneous neuro-immuno-endocrine system, which counteracts the action of external stressors and accommodates local homeostasis to the changing environment. The UVR induces electrical, chemical, and biological signals to be sent to the brain, endocrine and immune systems, as well as other central organs, which in concert regulate body homeostasis. To achieve its central homeostatic goal, the UVR-induced signals are precisely computed locally with transmission through nerves or humoral signals release into the circulation to activate and/or modulate coordinating central centers or organs. Such modulatory effects will be dependent on UVA and UVB wavelengths. This leads to immunosuppression, the activation of brain and endocrine coordinating centers, and the modification of different organ functions. Therefore, it is imperative to understand the underlying mechanisms of UVR electromagnetic energy penetration deep into the body, with its impact on the brain and internal organs. Photo-neuro-immuno-endocrinology can offer novel therapeutic approaches in addiction and mood disorders; autoimmune, neurodegenerative, and chronic pain-generating disorders; or pathologies involving endocrine, cardiovascular, gastrointestinal, or reproductive systems.
Changes in spatial self-consciousness elicit grid cell–like representation in the entorhinal cortex
Authors: Moon Hyuk-June , Albert Louis , De Falco Emanuela , Tasu Corentin , Gauthier Baptiste , Park Hyeong-Dong , Blanke Olaf
Published: March 2024

Grid cells in the entorhinal cortex (EC) encode an individual’s location in space, integrating both environmental and multisensory bodily cues. Notably, body-derived signals are also primary signals for the sense of self. While studies have demonstrated that continuous application of visuo-tactile bodily stimuli can induce perceptual shifts in self-location, it remains unexplored whether these illusory changes suffice to trigger grid cell–like representation (GCLR) within the EC, and how this compares to GCLR during conventional virtual navigation. To address this, we systematically induced illusory drifts in self-location toward controlled directions using visuo-tactile bodily stimulation, while maintaining the subjects’ visual viewpoint fixed (absent conventional virtual navigation). Subsequently, we evaluated the corresponding GCLR in the EC through functional MRI analysis. Our results reveal that illusory changes in perceived self-location (independent of changes in environmental navigation cues) can indeed evoke entorhinal GCLR, correlating in strength with the magnitude of perceived self-location, and characterized by similar grid orientation as during conventional virtual navigation in the same virtual room. These data demonstrate that the same grid-like representation is recruited when navigating based on environmental, mainly visual cues, or when experiencing illusory forward drifts in self-location, driven by perceptual multisensory bodily cues.
Protracted development in the heritage lexicon
Authors: Shang Mengyao , Zhao Lucy , Yip Virginia , Mai Ziyin
Published: March 2024

Research on heritage language acquisition at the school age has shown protracted development and early stabilisation in morphosyntax and the lexicon. Our study examined the properties of resultative verb compound (RVC), a structure at the crossroads of the lexicon and morphosyntax, in second-generation child heritage speakers in the UK who had continuous input in Mandarin Chinese since birth. We analysed three subclasses of RVCs produced by the heritage children (n = 27, age 4–14) and their parents (n = 18) in an oral narration task and compared them with those by children in Beijing (n = 48, age 4–9) from existing databases. Our results show that the heritage children produced RVCs quite frequently and felicitously yet highly repetitively and conservatively, with a remarkably large proportion of their RVCs consisting of a strongly lexicalised subclass with direct lexical equivalents in English. Correlational analyses show that the heritage children’s RVCs improve with age, rather than provision of RVC in the parental input, indicating the role of cumulative input in RVC acquisition. Overall, the development of RVC in heritage Mandarin is delayed rather than stabilised or attrited, supporting the lexical account for grammatical vulnerabilities in proficient heritage speakers.
Intuitive control of additional prosthetic joints via electro-neuromuscular constructs improves functional and disability outcomes during home use—a case study
Authors: Zbinden Jan , Earley Eric J , Ortiz-Catalan Max
Published: March 2024

Objective. The advent of surgical reconstruction techniques has enabled the recreation of myoelectric controls sites that were previously lost due to amputation. This advancement is particularly beneficial for individuals with higher-level arm amputations, who were previously constrained to using a single degree of freedom (DoF) myoelectric prostheses due to the limited number of available muscles from which control signals could be extracted. In this study, we explore the use of surgically created electro-neuromuscular constructs to intuitively control multiple bionic joints during daily life with a participant who was implanted with a neuromusculoskeletal prosthetic interface. Approach. We sequentially increased the number of controlled joints, starting at a single DoF allowing to open and close the hand, subsequently adding control of the wrist (2 DoF) and elbow (3 DoF). Main results. We found that the surgically created electro-neuromuscular constructs allow for intuitive simultaneous and proportional control of up to three degrees of freedom using direct control. Extended home-use and the additional bionic joints resulted in improved prosthesis functionality and disability outcomes. Significance. Our findings indicate that electro-neuromuscular constructs can aid in restoring lost functionality and thereby support a person who lost their arm in daily-life tasks.
Numerical Simulation Analysis of Typhoon Moving Track on Sea Surface Cooling
Authors: Li Jiagen , Wang Hanshi , Wang Huizan
Published: March 2024

Typhoons are mainly generated in the tropical ocean where the temperature is higher than 26°C. When typhoons move on the ocean, they will cause obvious sea surface cooling (SSC) along their track. The translation speed and moving direction of typhoons are two important components of the typhoons track, and they are also important factors affecting SSC. SSC reduces the heat flux from ocean to typhoons, and thus weakens the intensity of typhoons. Because the air-sea heat exchange mainly occurs in the inner-core region of typhoons, the SSC in the inner-core plays a crucial role in weakening the intensity of typhoons. Based on the numerical experiments, this study analysed the distribution of SSC caused by typhoons under different moving tracks. The results show that under the same ocean environment, typhoon intensity and translation speed, the inner-core SSC caused by sharp-right-turning typhoons is significantly stronger than that caused by the straight-moving typhoons (about 1.34 times) and sharp-left-turning typhoons (about 1.45 times). Without considering the air-sea heat flux, the contribution of vertical mixing to inner-core SSC is about 93.1% and that of advection is about 6.9% when typhoon is moving straight, and the contribution of advection is increasing with the increase of typhoon right turning angle.
Wave climate change analysis based on long time-series buoy data
Authors: Jiang Bing , Cao Liwei , Qin Shufang , Wang Yi
Published: March 2024

Using the buoy dataset from 2011 to 2022, the trend of wave climate change was analyzed at DaChen station located in the Taizhou City, Zhejiang Province. The results show a decreasing trend of the maximum significant wave height (Hs). Whereas the wave height is higher than 4 m, the corresponding wave period is in the range of 8-14s. Disastrous waves mainly occur between July and October. The relevant analysis presents the wave characteristics at the DaChen station, which is helpful for protecting the life safety along the coast and providing references for offshore engineering design.
A variational optimization algorithm for Secchi disk depth based on Multi-satellite data
Authors: Wang Yi , Xiang Jie , Zhou Shudao
Published: March 2024

A Secchi depth is a basic parameter to describe the optical properties of water, which is related to the composition and content of chlorophyll, suspended solids and yellow substances in water, and is also closely related to solar radiation on the surface of water, physical and chemical properties of water and meteorological conditions. The most direct way to obtain the spatiotemporal distribution of water Secchi depth is to use ships to regularly measure the Secchi depth of the base-stations, but this method can only obtain the Secchi depth of the measurement station state, and it is impossible to obtain the Secchi depth characteristics of seawater with large spatiotemporal distribution. As a brand-new observation method, remote sensing technology can obtain the distribution characteristics of ocean parameters in large time and space. In recent years, with the rapid development of remote sensing technology, especially the development of water-colored remote sensors and the improvement of the accuracy of inversion algorithms, many remote sensing products for water Secchi depth have been provided. However, due to the difference in orbit operation and observation parameters of different remote sensing loads, water Secchi depth products are affected by clouds and meteorological climate environment, and there is no same standard for verification and evaluation, which limit the promotion and application of water Secchi depth products. At the same time, data integrated technology has been widely recognized by many disciplines and has been greatly developed in recent years, and pixel-level, feature-level, decision-level integrated technology and development are also popular research directions in the world. Therefore, based on an improved variational optimization algorithm, this article integrates SDD retrieval products on multiple satellite data t such as SNPP, MODIS, and MERIS, and verifies them with ship survey data. The correlation is better than 0.9, proving that this method can improve the accuracy of SDD inversion products.
Quality Evaluation of Satellite Sea Surface Salinity Products in the Pacific Ocean
Authors: Dai Juan , Bao Senliang , Lu Jinming , Wang Huizan , Zhang Ren , Song Huajun , Zhou Yuanyuan
Published: March 2024

Sea surface salinity (SSS) is one of the most important variables in ocean dynamics and atmospheric climate. The launch of three salinity satellites, Aquarius, SMAP and SMOS, has greatly expanded the global sea surface salinity data field. The latest ocean surface salinity (CCI+SSS) fusion project fully utilizes the satellite data from SMOS, supplemented by SMAP and Aquarius satellite data, to merge into the CCI fusion product. In this paper, the data accuracy of the four SSS products, Aquarius, SMAP, SMOS and CCI, is evaluated in terms of both average deviation and root mean square error (RMSE) by comparing with the in situ SSS monthly gridded EN4.2.2 dataset in the Pacific Ocean. The results show that compared with the in situ EN4.2.2 data, the average deviation and root mean square error of the four SSS products are relatively small in the Pacific subtropical region, while the errors are generally higher in the cold water and offshore regions. Overall, the CCI product has the smallest average deviation and RMSE in the Pacific Ocean, which is the best performance among the four products.
Seasonal Variability of Global Intraseasonal SST Perturbations from 1982 to 2021
Authors: Liu Xin , Ge Yan , Yu Qinglong , Liu Yang , Zhang Weili , Yin Tienan
Published: March 2024

The seasonal variability of the intraseasonal SST perturbations is analysed based on the high spatial-temporal resolution and long-time series (1982-2021) OISST data. There are two bands of high intraseasonal variability (ISV, 20-90 days), one band is along the equatorial eastern Indian and western Pacific Oceans, the other is along the axis of the Antarctic Circumpolar Current (ACC). For large-scale perturbations, during boreal winter, the ISV of SST is large south of the equator, especially south of 30°S. During boreal summer, the situation is opposite and the ISV is more concentrated north of 30°N. During boreal spring, the ISV is increasing north of equator. During boreal autumn, the ISV is increasing south of equator while decreasing north of equator. For small-scale perturbations, the ISV of SST is large all the time over the Southern Ocean and western boundary currents. In the tropical ocean, the small-scale ISV in the eastern Pacific Ocean is apparent in summer and autumn. Compared to large-scale ISV, the distribution areas of the small-scale ISV are apparently narrower.
Optimizing wave simulation to improve the ocean circulation model in the North Pacific Ocean
Authors: Chen Wei , Shi Jian , Chen Jie , Zhang Wenjing , Zhang Shaoze
Published: March 2024

In this paper, the simulation performance of two source terms, ST4 and ST6, of the wave model WAVEWATCH III on significant wave heights is investigated in the North Pacific Ocean, and the root mean square error (RMSE), correlation coefficient (R) and mean absolute error (E
MAE) were compared between them, and all indices showed that the waves was better modelled by using ST4 in the North Pacific region. Based on the ST4 source term scheme, the Stokes drift is calculated from the wave elements simulated by WAVEWATCH III, and is added to the momentum equation of the SBPOM circulation model with the Stokes drift calculated by spectral integration, and it is found that the sea surface temperature (SST) simulated by the former scheme is better than that by the latter scheme by comparing with that of the Argo buoys, in which the RMSE is reduced by 0.018°C, E
MAE is reduced by 0.025°C, and R is improved by 0.007. Finally, by comparing the simulated Langmuir numbers of the two schemes, it is found that in most of the sea area (especially in the deep sea), the simulated Langmuir number of the former scheme is smaller than that of the latter scheme by about 0.1, which indicates the former scheme can be used to enhance seawater mixing, thus improving the accuracy of the coupled WAVEWATCH III-SBPOM model.
The Evaluation of the Impact of Meteorological and Marine Environment on the Combat Effectiveness of Surface Ships
Authors: Li Chenxin , Li Lifan , Feng Yunhe , Wang Duo
Published: March 2024

In recent years, the evaluation of the impact of meteorological marine environment on the combat effectiveness of surface ships has been an important content and hot topic in military oceanography research and naval battlefield support. In this paper, the analytic hierarchy process is adopted to establish the hierarchical structure of the evaluation model, determine the weights of each index, and quantitatively evaluate the proportion of the influence of wind, sea wave, rain, visibility, atmospheric waveguide, and other factors on the combat effectiveness of surface ships. Combined with marine hydrometeorological data examples, fuzzy comprehensive evaluation method is used to evaluate the index system, which can provide scientific and reasonable decision-making reference for ship commanders.
Assessment of typhoon disaster loss based on the factor analysis-random forest model
Authors: Liu Xu , Liang Yingqi , Fu Xiang , Wang Zheng , Cai Wenbo , Zhao Dajun
Published: March 2024

Typhoon disasters in China’s coastal areas pose significant challenges for disaster prevention and mitigation, urban planning and national economic construction. This study aims to address the problem of incomparable disaster assessment indicators and low prediction accuracy of machine learning for small sample data. It establishes an index system based on the practical disaster investigation classification standards, which ensures data sources and uniformity. It also proposes a combination algorithm of factor analysis-random forest regression for direct economic loss prediction, which improves the typhoon disaster losses prediction. The results show that the optimized model has higher accuracy than single decision tree model, random forest model and factor analysis-decision tree model. The factor analysis method verifies the importance of influencing factors, which indicates that China faces great risks of coastal floods caused by super typhoons. The combination regression model can predict disaster losses reasonably, providing effective technical support for typhoon disaster assessment and management.
Research on numerical simulation method for 3D marine direct current resistivity
Authors: Ling Jiaxuan , Deng Wei , Liu Siqin , Chen Qingrui , Wei Shiwei , Li Mengmeng , Wei Shuliu
Published: March 2024

As one of the most important methods in marine electromagnetic exploration, the marine direct current (DC) resistivity method has been widely used in the exploration of marine minerals, oil and gas, as well as in large-scale engineered geological exploration and other fields. Efficient and high-precision forward algorithms are the foundation for an accurate quantitative interpretation of the marine DC resistivity method. We have implemented an efficient and high-precision forward modeling approach for 3D marine DC resistivity. First, the wave number domain anomalous potential control equations are obtained by performing a 2D Fourier transform along the horizontal direction based on the differential control equations satisfied by the marine DC anomalous potential. Instead of directly solving the 3D numerical simulation problem, we transform the 3D numerical simulation problem into multiple 1D numerical simulation problems in the wavenumber domain by dimensionality reduction for computational efficiency. Second, the boundary conditions of the governing equations are given to obtain the corresponding boundary value problems, and the anomalous potential is solved using the 1D finite element method in the wavenumber domain. Next, we perform a 2D inverse Fourier transform on the wave-number domain anomalous potential to obtain the spatial domain anomalous potential. Furthermore, compact operators are used to iteratively modify the potential and obtain high-precision numerical solutions. Finally, we demonstrate the correctness of the proposed algorithm’s solution strategy by using a hierarchical ocean model, and the efficiency of the proposed algorithm by using a spherical model.
Sea ice detection network for icebreakers in polar environments with attention-based deeplabv3+ architecture
Authors: Li Sheng , Wang Min , Wu Jia , Sun Shuo , Shi Minghang , Ma Rui
Published: March 2024

Shipborne sea ice detection aboard icebreakers plays a paramount role in polar navigation. The continuous evolution of deep learning semantic segmentation networks has promoted the advancement of sea ice detection tasks. At this stage, there are relatively few studies on shipboard sea ice detection, and the accuracy of polar sea ice detection will be reduced due to problems such as blurred sea fog and indistinct boundaries. In this study, a shipboard sea ice detection dataset is constructed, and a sea ice detection method that combines multi-branch attention feature alignment and multi-scale feature extraction is proposed. The heterogeneous receptive field enhancement atrous spatial convolution pooling pyramid module is designed, and the feature alignment module based on the attention mechanism is constructed, which strengthens the model’s extraction of sea ice features and elevates representation performance. Experimental results underscore the heightened precision of our approach in sea ice detection, to some extent alleviating the issue of missed detections in new ice. It constitutes a positive contribution towards advancing shipborne sea ice detection in polar environments.
Noise Generation Mechanisms of Marine Composite Pipelines Excited by the Internal and External Flows
Authors: Lin Yukun , Feng Baoming , Kang Rongjun , Liu Yongwei
Published: March 2024

The marine pipeline is an important energy transportation platform today. It can cause underwater noise pollution due to sound radiation caused by pipeline vibration during oil and gas transportation. This study focuses on the noise-generation mechanisms of marine composite pipelines under internal and external flow excitation. We investigated the impact of different materials, diameters, and wall thicknesses on the sound radiation characteristics of the pipeline under internal flow excitation. The relationship between radiated sound power and flow velocity was analysed. Additionally, we discussed the radiated sound field of marine composite pipelines under external flow excitation. Our results show that the radiated sound power under internal flow excitation is over 20 dB higher than that under external flow excitation in the 10 Hz to 2000 Hz frequency range. We conducted an experimental test near Zhoushan city, China, where the internal flow was driven by a pump and the external flow represented ocean currents. The results confirmed that the main noise-generating mechanism of marine composite pipelines is internal flow excitation. The numerical findings were validated by the experimental test. Overall, this paper provides a foundation for future investigations into the sound radiation of marine composite pipelines.
Acoustic scattering characteristics of underwater buried oil pipeline
Authors: Yin Jiancheng , You Xiangyu , Yao Yu
Published: March 2024

With the development of offshore oil resources, subsea oil pipelines have emerged. As a fast, economical, and safe way to transport oil resources, subsea pipelines are known as the “lifeline” of offshore oil projects. However, the detection of submarine pipelines is very difficult due to the complex underwater environment. One of the mainstream methods to detect submarine pipelines is the employment of sonar. Hence, the acoustic scattering characteristics of submarine pipelines play an important role in detecting themselves. In this study, the acoustic scattering model of the buried pipeline is established using the finite element method, and the scattering mechanism of the buried pipeline is analyzed. The effects of different frequencies, grazing angles, burial depth, and other factors on the acoustic scattering characteristics of the buried pipeline are investigated, providing the reference significance for detecting submarine pipelines.
An interpretation experiment on eddies’ role in sound propagation in the ocean using ray model
Authors: Kuang Xiaodi , Zhang Zhiyuan , Li Jingshi , Yuan chengyi
Published: March 2024

The relationship between mesoscale eddies and ambient acoustic propagation under different conditions were studied using high resolution ocean reanalysis products in South China Sea, which was summarized by a linear-equation representing the convergence zone change with respect to eddy signatures and source positions. Beyond the experiments scales, warm eddies “dragged” the sound propagation and cold eddies “squeezed” that in contrast, and the acoustic amplifying mechanism can be summarized as stronger(eddies), nearer(eddies) and deeper(source).
Random medium modeling and underwater acoustic field simulation
Authors: Zheng Guangxue , Piao Shengchun , Gong Lijia , Sun Yu
Published: March 2024

The von Karman random medium model is established based on the small scale random medium theory in this paper. Combined with the finite element theory, the numerical simulation of the sound field under this model is realized by using the spectral-element method, and the characteristics of the sound field are compared with those under the uniform medium underwater environment. The results show that the correlation length reflects the variation of the heterogeneous size, and the scattering wave generated by random disturbance may provide a more reasonable explanation for the amplitude and energy anomalies in some trial data.
High resolution spectrum estimation of virtual array based on FIM
Authors: Cai Yu , Liu Benqi , Pan Xiefan
Published: March 2024

Underwater small aperture sonar spectral estimation methods are limited by physical dimensions, resulting in insufficient azimuthal resolving power. In this paper, we propose that based on the Fourier Integral Method(FIM) equivalent to a virtual array of extended aperture, after using subarray smoothing, combined with the spectral estimation method, we get the improved FIM-CBF, FIM-Capon and FIM-MUSIC, and give the applicable conditions of these three improved methods, and use the virtual aperture expansion and noise averaging suppression, to achieve the improvement of the azimuthal resolving power of the spectral estimation method under the low SNR.
The Average Sound Energy Spectrum Produced by a Single Raindrop
Authors: Liu Shu , Wang Jian , Chen Yu , Wang Jiru , Zhu Jing , Chen Wei , Bian Yujie
Published: March 2024

The characteristics of underwater acoustic radiation generated by a single raindrop impacting the water surface play a fundamental role in the study of rainfall noise. However, the underwater sound signal generated by a single raindrop has great randomness in the amplitude of sound pressure, frequency range and energy size, so that the uncertainty of the sound energy spectrum curve of a single raindrop is relatively large. In this paper, by generating artificial rainfall containing only one size of raindrop, the acoustic radiation generated by artificial rainfall composed of about 136,000 raindrops with an equivalent diameter of 0.9 mm was measured by reverberation method. A smooth, continuous sound energy spectrum of single raindrop covering the full frequency band is obtained.
Error analysis of IMU pipeline bending strain detection based on full-scale test
Authors: Shi Tong , Liu Xiaoben , Lu Yanan , Zhang Haoning , Li Rui , Fu Kuan , Feng Qingshan , Huang Qiyu
Published: March 2024

The strain identification technology based on inertial mapping unit (IMU) internal detectors is currently a widely used internal detection technology for identifying pipeline bending strain both domestically and internationally. It calculates the bending strain of the entire pipeline through the detected centerline coordinate data. However, there are issues such as abnormal vibration and noise during the actual operation of the inertial navigation internal detector, as well as trajectory deviation during the detector’s operation. This issue leads to a certain deviation between the strain detected by IMU and the actual strain of the pipeline. This article utilizes a self-designed full size pipeline bending strain loading device to conduct full size pipeline bending strain tensile tests. Compare the internal detection data obtained from the experiment with the actual bending strain data of the pipeline and conduct error analysis. The research conclusion indicates that as the bending strain increases, the error between the IMU detection strain and the actual strain of the pipeline increases. When there is vibration noise, the maximum error is 0.077% for 0.33% true strain, and the maximum error rate for larger strain segments is 27.1%. The comparison between noise reduction detection data and true strain shows that when the true strain is 0.12%, 0.21%, and 0.33%, the average error is 0.0285%, 0.0315%, and 0.0555%, respectively. The research conclusion provides technical support and guidance for obtaining true strain of pipelines based on IMU internal detection in the future.
Design of ammonia leakage online monitoring system based on tunable diode laser absorption spectroscopy
Authors: Jia Ribo , Gao Junbo , Yang Shenhao , Cheng Junna
Published: March 2024

A real-time online ammonia volume fraction monitoring system based on tunable diode laser absorption spectroscopy (TDLAS) is designed to meet the demand for ammonia gas leakage monitoring in ammonia-fueled ships. The system uses a 1, 512 nm distributed-feedback (DFB) laser as the light source and a 5 m high-temperature Boss-Gas-Cell as the absorption cell. By applying a 4 Hz scan signal and a 31.4 kHz modulation signal to the laser current, the effective absorption signal of the gas is transferred to the high-frequency band, then the second harmonic (2f) signal about gas volume fraction is extracted by a digital lock-in amplifier from the gas absorption signal, and ammonia volume fraction can be calculated from the amplitude of 2f signal. The test results show that the ammonia detection accuracy in the range of 0-500 ppm can reach ±1% FS, the response time is less than 30 s, and the system measurement repeatability is less than 1%, which meets the needs of ammonia leakage monitoring in ammonia-fueled vessels.
Design of power supply system for portable aviation inspection equipment
Authors: Yang Yang , Ai Hao , Li Shibo , Xiao Guokai
Published: March 2024

Given that airborne electronic equipment may have a variety of wiring methods and may encounter a set of systems using multiple power supplies, it is necessary to take some measures on the circuit to ensure the normal work of the power supply and the post-circuit. A portable aviation detection equipment power supply system is designed in this paper. The system supports simultaneous access of two power supplies to identify and judge the input power supply and switch between the battery and the external power supply, effectively avoiding the security risks caused by battery backflow current. The battery power is monitored in real-time through the battery power detection circuit and will be reminded when the battery power is too low. Since the circuit uses a MOS tube to control the switching of the power supply, there is almost no voltage drop loss. In addition, the EMC protection circuit is set up at the power supply side to further improve the safety and reliability of the system.
Structure design and deformation analysis of double hydraulic cylinder deep-sea pressure simulator
Authors: Wu Jianmei , Li Yang
Published: March 2024

Because of the particularity of the deep-sea environment and the difficulty of on-site observation and research, it is particularly important to establish a deep-sea simulation system for research. Based on the high measurement accuracy requirement of deep-sea simulation equipment, a design scheme of a deep-sea pressure simulation device with a double hydraulic cylinder that can measure small water pressure changes is proposed. Firstly, the working parameters and pressure principle of the design are introduced, and then the deformation of the deep-sea pressure simulation device is analyzed. The mathematical model of piston feed and pressure without considering the deformation of the sealed pressure cylinder and the mathematical model of piston feed and pressure considering the deformation of the sealed pressure cylinder are established respectively. Finally, the relationship curve is analyzed by using origin software. The results show that when the deep-sea pressure simulator is used to simulate the underwater environment, it is necessary to consider not only the influence of liquid compression on the pressure but also the influence of deformation on the pressure.
Global sensitivity analysis of fatigue life based on structural health monitoring
Authors: Liu Shiyu
Published: March 2024

Fatigue cracks are one of the most common causes of structure failure. Structural health monitoring (SHM) has shown important practical significance in ensuring the safety of civil infrastructures by providing continuous, accurate, and reliable monitoring at low cost. Given that data provided by SHM involves various types of uncertainty, this study presents the interval-random hybrid model for fatigue life based on fatigue crack growth theory. By introducing global sensitivity indices, the influences of different variables on the variance of structural fatigue life are analyzed. To enhance computational efficiency, the method is proposed by combining the space partition with unscented transformation (SP-UT).
Stress detection method of pipeline based on vibration characteristics
Authors: Li Jinzhou , Liu Xiaoben , Shi Tong , Zhang Hong , Wang Hao , Sha Shengyi , Bu Mingzhe
Published: March 2024

Stress concentration during the operation of long-distance transmission pipelines is an inevitable problem. In this paper, a pipeline stress detection method based on vibration characteristics is proposed. We establish a finite element model for knock detection and determine the law of vibration frequency and pipeline stress. The reliability of the model is verified by the knock detection experiments. It is found that the natural frequency stress of the vibration of the sample shows a close correlation under the knocking effect. The study results provide an innovative process for pipeline stress detection.
Application of calibration-free wavelength modulated spectral absorption technique in temperature measurement under ultra-short optical path
Authors: Ren Yunhao , Gao Feng , Duan Xiaoming , Cai Yu , Li Yachao , Zhou Yihui
Published: March 2024

The measurement of gas temperature parameters is of great significance in scientific research and industrial production. Wavelength modulation technology, as a non-contact optical detection means, has the characteristics of strong anti-interference ability and is widely used in various complex and harsh environments. The accuracy of temperature measurement is affected by short optical paths and weak absorption. In this paper, a calibration-free wavelength modulated ultra-short optical path measurement system is established, and the selection rules of spectral lines under the ultra-short optical path and weak absorption are proposed. The measurement results of wavelength modulation without calibration are in good agreement with those of thermocouple temperature measurement, and the relative error is less than 10%.
Noise reduction analysis of deformation data based on CEEMD-PE-SVD modeling
Authors: Duan Qingda , Xia Hua , Huang Ya
Published: March 2024

In the field of high slope deformation monitoring, the deformation data obtained are often characterized by high volatility, strong nonlinearity, and noise content, due to the influence of factors such as the surrounding environment, human operation, and the complexity of the project. To overcome these problems, this paper proposes deformation data based on the coupling of complementary ensemble empirical modal decomposition (CEEMD), permutation entropy (PE), and singular value decomposition (SVD). Firstly, CEEMD decomposition is performed on the deformation data. Secondly, a randomness test is performed on the obtained modal components, and if the entropy value of the component arrangement entropy is greater than 0.5, SVD decomposition will be used for noise reduction. Finally, the components that meet the conditions are reconstructed to realize the noise reduction of the deformation data. The results show that the algorithm model has an excellent noise elimination effect, which can reflect the internal detail information of deformation data and provide a well-established method for future research on the processing of deformation monitoring data.
Multi-View consistency-based point cloud registration method with low overlap rate
Authors: Cui Zhiqiang , Liao Zhaoyang , Lin Xubin , Sun Kezheng , Cheng Taobo , Zhou Xuefeng
Published: March 2024

Accurate and efficient workpiece measurement is crucial for workpiece processing and quality monitoring. Non-contact optical measurement methods have gained more attention due to their simplicity, efficiency, and flexibility compared to complicated and inefficient contact measurement methods. Multi-view registration of measurement data is a key issue in workpiece measurement, as it relies on the system’s geometric accuracy and motion stability, presenting challenges such as the insufficient overlap of multi-viewpoint cloud data and cumulative error. To address these challenges, this paper proposes a multi-view planning and registration algorithm with a low overlap rate. The multi-view planning algorithm employs a greedy method to plan the scanning viewpoints of the workpiece to obtain complete point cloud data efficiently. The multi-view registration algorithm extracts features using a multi-scale geometric feature extraction network, matches the features based on the Hungarian algorithm, builds a graph, and optimizes workpiece positions based on the G2O algorithm for multi-view registration, effectively reducing cumulative error. Measurement experiments on blade workpieces confirm the feasibility of the proposed algorithms.
Temperature compensation for piezoresistive pressure sensor based on deep learning on graphs
Authors: Xue Mingyao , Fang Ting , Hu Chenghe , Dong Chong , Han Jiaming
Published: March 2024

With the escalating demand for precision in piezoresistive pressure sensors to cater to a wide spectrum of applications, a significant challenge emerges due to the material properties of these sensors, which induce a substantial temperature coefficient. This limitation restricts the operational temperature range and is further exacerbated by ambient temperature variations, resulting in pronounced nonlinearity in sensor responses. To address these challenges, A new method using Graph Neural Networks (GNNs) is introduced to address nonlinearity and temperature drift in piezoresistive pressure sensors. GNNs improve the sensors’ accuracy and reliability across different temperatures, expanding their applicability. Test results show a notable accuracy enhancement, with a maximum full-scale error below 0.05% and even lower in specific ranges (under 0.04%). This precision makes the method ideal for industrial pressure sensor applications and production, offering significant benefits.
Research on low power consumption of wireless MEMS methane sensor
Authors: Zhang Haiqing
Published: March 2024

Aiming at the problem that the high power consumption of traditional methane sensors does not realize the comprehensive detection of coal mines underground, based on MEMS methane detection technology, wireless methane sensing low-power research is proposed. First of all, based on the analysis of power correlation, we select the modularized design with low power, which includes power supply, sensing element driver, acquisition, and processing modules. We study the change of sensitive resistance, response time, and power consumption of the MEMS methane sensing element and sensor in different operating modes. Meanwhile, experimental tests are carried out. The experimental result shows that under the premise of ensuring the timeliness and stability of methane gas detection, the power consumption of the wireless MEMS methane sensor in one minute is only 2.4% of the traditional catalytic methane sensing element.
A windowed fourier transform-based method of numerically analyzing phase shifts of SPR sensors
Authors: Peng Shikang , Wang Guofu , Liu Yansheng , Jia Xiaobo , Zhou Jin
Published: March 2024

This study presents a simple and reliable method for numerical evaluation of the sensitivity of SPR systems. A Windowed Fourier Transform (WFT) based method is applied to extract shifts of SPR interferogram. By applying the WFT, the frequencies consisting of SPR interferogram are extracted, and phase shifts of relevant frequencies are also obtained. The normalized amplitude of the frequencies larger than 0.35 is regarded as the most prominent frequency. The summation of the phase shifts of the most prominent frequencies is regarded as an index to numerically analyzing phase shifts of SPR sensors. Through this method, the small change in the sensing surface can be monitored. By using a homemade SPR system with the proposed calculation method, it can detect the NaCl solutions ranging from 0.00003% to 0.03% (wt%), indicating its great promise for applications in fields such as medicine, food safety, and biotechnology.