bluuebunny/crossref_metadata_2025 huggingface dataset:
The mean scatterer spacing estimation with the Gabor atoms selected based on the Nakagami distribution
Authors: Zeng Xiuhua , Wu Keyan , Yang Taoxiang
Published: October 2024

Mean scatterer spacing (MSS) is a quantitative signature for disease diagnosis and tissue characterization. However, it is difficult to objectively extract the coherent components from the ultrasound RF echo signals to improve the accuracy performance of the MSS estimation. In the present study, a novel MSS estimation method with the matched Gabor atoms selected based on Nakagami parameters is proposed. Firstly, the ultrasound signals are decomposed into a series of Gabor atoms, and the envelopes of the residual signals are fitted with the Nakagami distribution. Then, the second order difference (SOD) of the shape parameters in Nakagami distribution is calculated to select the optimal atoms to match the coherent components. Finally, the locations of the selected Gabor atoms are used to estimate the MSS. In order to evaluate the performance of the proposed method, the simulated RF echo signals are modelled based on four regular degrees of the scatterer distributions, and then the optimally matched atoms are selected to estimate MSSs. The results based on simulated signals demonstrate that the propose method can provide accurate MSS estimation, which are advantageous for improving quantitative diagnosis of diseases and tissue characterization
A new inversion method for imaging near-wellbore radial slowness based on array acoustic logging data
Authors: Wang Z , Yue W Z , Zhu Y M
Published: October 2024

The slowness of near-wellbore formation is critical to geophysical exploration as it can be used to evaluate rock brittleness, wellbore stability, fracturing effect, and invasion depth. Conventional methods for investigating radial slowness profiles of both compression wave and shear wave near-wellbore are time-consuming and depend on the extracted arrival time of the first wave. Additionally, these methods cannot simultaneously conduct the profile inversion of the compression and shear waves. We develop a new inversion method for imaging near-wellbore radial slowness to overcome these limitations. It can adaptively extract slowness and its corresponding radial thickness from array acoustic logging data. The new method adaptively extracts slowness sequences with different radial depths by combining receivers with different source distances. The thickness corresponding to the slowness sequences can be obtained by combining the slow sequence with the ray theory, and finally, the radial slowness profile can be obtained. an example of synthesis using the FDTD method is presented. The results show that the algorithm is stable and reliable. Overall, this study highlights the value of radial slowness imaging as a powerful tool for wellbore analysis and reservoir characterisation.
Dipole acoustic remote detection (ARD) logging and its application in fracture-cave reservoir
Authors: Wu Baizhi , Dong Jingli , Xu Xiaokai , Du Qunjie , Zhai Yong , Chen Hao , Chao Yongsheng , Zhang Weifeng
Published: October 2024

Oil and gas from deep reservoirs are mostly enriched in the fracture-cave reservoirs. For this reason, fine evaluation of large-scale fracture-cave and effective detection of small scale fracture-cave are the key issues to be solved in the exploration of fracture-cave type carbonate reservoirs. The acoustic remote detection logging technology is based on acoustic reflection method to continuously image the formation around the well. The cross dipole array sonic data can be processed to image geological anomalies within a range of about 20 meters outside the well. Dipole S wave remote detection has the remarkable advantages of low emission frequency and larger investigation depth, but it has 180 degrees’ azimuthal ambiguity. This study is based on previously developed far field dipole S wave remote detection tool, finite difference is performed on formation models with and without are obtained for representative fracture-cave formations and remote detection processing and interpretation software is updated. These are applied on a well in the northwestern area. Through the comprehensive analysis of remote logging, conventional logging, electrical imaging logging and seismic data of the fracture-cave geological anomalies, a fine picture of the morphology and development of the geological anomalies from the near wellbore to the far end is formed
Reflection and transmission characteristic waves on the periodic rough interface of fluid-porous medium
Authors: Zhang Yujing , Han Qingbang , Su Nana , Wu Yang , Jin Qilin , Sun Liujia
Published: October 2024

Nondestructive testing (NDT) is a major method in practical applications such as material exploration and safety assessment. The interaction of ultrasonic waves with roughness material is crucial in NDT, thus the related ultrasonic diffraction theory at the rough interface is widely investigated and analyzed, especially for the periodic elastic medium interface. However, the actual surface is usually porous due to the long-term moisture infiltration. In this paper, the reflection and transmission characteristics of ultrasonic waves on the fluid-porous medium periodic rough surfaces are studied in details.
Adaptive adjustment method of segment linear frequency modulation excitation for wideband dipole logging
Authors: Cao Xueshen , Chen Hao , He Hongbin , Zhou Yinqiu , Chen DeHua
Published: October 2024

Wideband dipole signal is the basis for dipole dispersion correction and near-borehole imaging. Segment linear frequency modulation (SLFM) sound source signal is an effective method to broaden the dipole frequency band. In the actual logging process, the formation environment changes in real time, and the SLFM sound source with fixed parameters cannot compensate the bending wave excitation intensity curve at any time, which affects the quality of logging. This paper presents a method for adaptive adjustment of the SLFM sound source signal. Adaptive parameter adjustment can be made according to the change of downhole environment, so that the signal can be adapted to the changing downhole geological environment.
Efficiency analysis of laser ultrasonic longitudinal wave detection based on the constraint effect
Authors: Guo Xing , Chen Youxing , Xun Yanqin , Wang Zhaoba , Li Ya
Published: October 2024

Laser ultrasound is a non-destructive inspection technique, but its application in internal defect detection and state characterization is limited by its weak body wave displacement induced by thermo-elastic mechanism. In this paper, the influence of the constraint layer on the directivity of laser induced ultrasonic force source and the excitation efficiency of longitudinal wave is analyzed by finite element modeling with transparent glass as the constraint layer. With the optimization of the parameters of the confinement layer, the longitudinal waves with energy comparable to that of the free surface ablation mechanism can be excited under the thermoelastic mechanism, which greatly improves the efficiency of the longitudinal wave of laser ultrasonic. Applying the above research results to the detection of internal defects, the imaging results of the internal defects are obvious and the location defects are accurate.
Study on the influence of typical turbulent flow field on the metering performance of cross four channel ultrasonic flowmeter
Authors: Zhou Chang , Xing Chao , Meng Tao , Wang Yiwen , Shi Huichao
Published: October 2024

In this paper, influence of typical turbulent flow field on a multi-channel ultrasonic flowmeter was studied. Experimental sample of the cross four-channel ultrasonic flowmeter were designed and processed, and CFD simulation models of flowmeter and right-handed spoiler, gate valve and velocity profile spoiler were established. Through simulation, the turbulent flow field behind typical spoilers such as right-handed spoiler, gate valve and velocity profile spoiler, and the influence of turbulent flow field on the metering performance of the cross four-channel ultrasonic flowmeter were studied. On this basis, the CFD simulation results and the real flow experiment results were compared and analyzed, and the reliability of the CFD simulation analysis results was verified, which provides the research basis for improving flowmeter performance.
Research on 3D Reconstruction of Paleontological Fossils Based on Photoacoustic Microscopy
Authors: Sun Mengyu , Zhong Yuanxin , Qin Zhengwang , Liu Zheng , Gao Chunming , Gong Yanli
Published: October 2024

The focus on three-dimensional morphological analysis of endogenous trace fossils has emerged as a prominent aspect in the study of palaeobiological fossils. Photoacoustic imaging technology, renowned for its deep penetration, high resolution and non-destructiveness, holds considerable promise in exploring fossil morphology. In this work, a solid-coupling-based photoacoustic microscopic imaging system was developed, leveraging this technology to investigate small-scale physical fossils. The proposed system enabled layered imaging of various fossil specimens, achieving a lateral resolution exceeds 35 μm and an axial resolution superior to 8.8815 μm. The three-dimensional reconstruction results were obtained through image processing algorithms. This system was proved to be efficient to imaging the small-scale physical fossils.
Simulation study of Rayleigh wave inspection of subsurface white etching crack in bearing rollers
Authors: Wu Chenchen , Zhu Qi , Su Zhan , Xu Duo , Zhang Haiyan
Published: October 2024

Rolling bearings are widely used in wind energy and electric vehicle industries. One of the premature failure mode due to the contact fatigue is White Etching Crack (WEC) in the subsurface. WEC occurs preferentially in the Hertzian contact region of bearings, preferentially around multi-phase inclusions containing aluminium, manganese, and sulfur. The formation process undergoes intense plastic deformation and recrystallization. Most of WECs are 100~300 μm below the contact surface in a butterfly shape. Its principal axis is 30°~50° to the rolling direction. Since the sample preparation is difficult, this simulation study enables to better understand the interaction between WEC and ultrasonic waves for a better measurement system design. Rayleigh surface wave penetrates to a depth of about an order of magnitude of one wavelength. Its energy is concentrated near the surface containing rich WEC information. The Rayleigh wave propagation process is first analyzed based on the grain scale model established. Then the immersion inspection of WEC is simulated based on the finite element method at 15 MHz in order to compromise between the detection accuracy and defect depth. Finally, by analyzing the time and frequency domain information of the scattered signals, the quantitative relationships between crack characteristics (depth, length and tilt angle) and those of Rayleigh waves (amplitude and attenuation) can be obtained. This study paves the way for the quantitatively characterization of WEC in bearing rollers with surface integrity evaluation possibility at early stage.
Ultrasonic evaluation of wire arc additively manufactured parts with heterogeneous microstructure
Authors: Cai X , Canturri C , Shandro R , Aishwarya  , Zhai W , Dupont B , Callejon A , Fan Z
Published: October 2024

In Wire Arc Additive Manufacturing (WAAM) components manufactured by gas metal arc welding strategy, periodically alternating patterns of fine- and coarse-grained microstructures develop along the building direction, depending on the temperature evolution. Ultrasonic non-destructive evaluation relies on the scattering of waves from defects. In the material microstructure, ultrasound waves are also scattered at the grain boundaries as grain noise. The work presents a study on the influence of heterogeneous microstructure in WAAM on defect detectability during ultrasonic inspections. The study used a 2D finite element model to simulate ultrasound wave propagation in the material microstructure represented by a surface element from electron backscatter diffraction scans. Side-drilled holes were introduced in the material as defects. Phased array was used to perform full matrix capture and obtain ultrasound image through total focusing method, with dynamic focusing capability to inspect the heterogeneous microstructure. The study analysed the defect echoes and noises using the signal-to-noise ratio (SNR) to assess its defect detectability. While defects were well detected, the SNR values differ by 10% for defects at various positions along the building and transverse directions in the heterogeneous microstructure.
Quality Evaluation of Argan Oil as a Food Product Using Ultrasonic Characterization
Authors: Ettahiri Mohamed , Hamine Adil , Ouacha El Houssaine , Mesbah Hicham , Tafkirte Mounir
Published: October 2024

Start This study focuses on evaluating the quality of food-grade argan oil, an essential component of Moroccan cuisine, using experimental ultrasonic characterization. Variations in ultrasonic velocity and attenuation with temperature were exploited as significant parameters for quality control of argan oil. The results reveal an inverse correlation between ultrasonic velocity and temperature, providing a unique model for the studied samples of argan oil. The measurements also show that the acoustic attenuation of argan oil decreases with temperature, while it increases with the volumetric fractions of sunflower oil added to argan oil. The data collected during this experimental study demonstrate that the velocity of the mixture of argan oil and sunflower oil increases with rising temperature. It was observed that both ultrasonic parameters of this mixture are challenging to detect by ultrasound. Ensuring the reproducibility of measurements under the same conditions, reference graphs are established to detect adulteration, especially when considering blends of argan oil with sunflower oil.
Adaptive total focusing method for ultrasonic full-matrix imaging of anisotropic CFRP laminates
Authors: Yu Zhenyang , Jin Haoran , Chen Jian
Published: October 2024

The application of total focusing method (TFM) for imaging of Carbon fiber reinforced plastics (CFRP) with ultrasonic phased array is particularly challenging due to the layered structure and anisotropy of CFRP. To improve the TFM imaging performance, the precise knowledge of complex ultrasonic paths in anisotropic CFRP laminates should be obtained for accurate calculation of time of flights (TOFs), which makes the inspection process complicated and time-consuming. In this work, an adaptive TFM is developed for full-matrix imaging of CFRP laminates using ultrasonic phased array. Based on the acquired full matrix data, the elastic constants, including C
11, C
22, C
55, and C
13, can be directly derived using TOFs of A-scan signals. Based on the measured elastic constants, group velocity profiles of quasi-pressure (QP) wave were then calculated for different stacking sequences, from which the TOFs were corrected. To verify the effectiveness of proposed method, simulations and experiments are demonstrated on the CFRP laminates with different stacking sequences. As a representative example, the delamination defects are showcased. Compared with isotropic TFM, the SNR of proposed method is increased by 10.2-18.0 dB. The simulated and experimental results agreed well with each other, indicating that the feasibility of proposed method in full matrix imaging of anisotropic CFRPs.
Subsurface defect detection of high-temperatured components with laser induced surface wave
Authors: Zeng YK , Qiu SY , Li FH , Chen J
Published: October 2024

Subsurface defects are detrimental to the safety and integrity of critical components in various fields, particularly for those used in high-temperature environments. For this reason, a reliable non-destructive evaluation (NDE) method for in-situ inspection of subsurface defects of high-temperatured components is highly desired. Laser ultrasonic technique offers a promising potential to accommodate the demands in virtue of non-contact generation and detection of ultrasonic waves. In this work, laser ultrasosnic inspection of subsurface defects in high-temperatured components is proposed, which exploits the modal conversion of surface longitudinal wave to Rayleigh wave. The modal conversion was firstly investigated with finite element simulation, from which the phenomenon of modal conversion can be readily identified. Thereafter, an experimental setup is built to verify the feasibility and effectiveness of proposed method. Notably, a delay-and-sum method based on a scanning procedure is conducted to coherently increase the detection sensitivity of subsurface defects, since the surface longitudinal wave rapidly vanishes with propagation distance., and the temperature-dependant velocity variation can be adaptively compensated. This work provides a viable route for in-situ inspection of subsurface defects in high-temperatured components where conventional ultrasonic method fails, and it would find potential applications in broad fields, such as coating quality evaluation in fabrication, bearing assessment under load, and in-situ monitoring for additive manufacturing.
Sparse-TFM imaging in frequency domain based on amplitude-squared parameter
Authors: Li Xiao , Luo Zhongbing , Shi Siqi , Jin Shijie
Published: October 2024

The total focusing method (TFM) implemented in time domain has high complexity, limiting its large-scale engineering applications. In contrast, the frequency-domain TFM based on phase shift migration (PSM) is helpful to improve imaging efficiency. On this basis, partial data can be abandoned for imaging to save computing costs and shorten processing time without reducing imaging quality. In this paper, an adaptive sparse-TFM in the frequency domain is proposed by selecting desired signals from full matrix capture (FMC) data. The amplitude-squared parameter for all the received signals corresponding to each transmitting element is taken as the relevant weight, and sparse arrays are constructed adaptively according to the descending order of numerical values. Simulated and experimental results indicate that the proposed method has stable imaging quality under different sparsity ratios, rapidly improving imaging efficiency with good resolution for defect detection.
The hydrodynamic noise suppression of the towed array by the combination of the flow and sustained release
Authors: Yong-Wei Liu , Rong-Jun Kang , Chun-ting Gu
Published: October 2024

This paper proposes a jet flow release method based on fish mucus to reduce the flow noise of the towed array. This method aims to alleviate the adverse effects of turbulent fluctuating pressure on the self-noise of a towed array at high speeds and address the problem of target signal masking caused by flow noise. A circular jet nozzle is installed at the front end of the towed array to spray mucus backward, reducing the turbulent fluctuating pressure on the surface of the towed array and improving the signal-to-noise ratio. Large eddy simulation using Fluent and finite element calculation of the acoustic field using Actran are employed to obtain flow and acoustic field results, respectively. The research findings demonstrate that after spraying mucus through the jet nozzle, the model’s viscous drag is reduced, and the excitation on the surface is significantly decreased, leading to a noticeable reduction in the self-noise sound pressure level in the frequency range of 150–2000 Hz.
Iterative processing of the noise coherence matrix to determine the acoustic properties of the water area
Authors: Dmitriev K V
Published: October 2024

An expression is given for the coherence matrix of the acoustic field produced by random sources in an inhomogeneous medium in the Born approximation. An iterative algorithm is proposed to determine the wave number inside the inhomogeneity based on this expression. The reconstruction results are analyzed for the cases of precise input data, data with interference, and incomplete data.
Self correction technique for amplitude and phase errors of underwater acoustic arrays based on variable decibel Bayesian inference
Authors: Zhao Ounan , Wang Qing , Chen Xiaosen , Wang Fangyong , Du Shuanping
Published: October 2024

Direction of arrival (DOA) estimation of underwater targets is an important research direction in the field of underwater acoustic array signal processing. Due to factors such as assembly errors and component aging, amplitude and phase errors between each channel of the array are common, resulting in distortion of the array flow pattern matrix. At the same time, the non-uniform distribution of noise intensity at the positions of each array element further increases the difficulty of DOA for underwater targets. Based on the characteristics of sparse spatial distribution of underwater targets, this paper uses the flexibility of hyperparametric modeling to construct an array observation signal graph model. On this basis, the effects of amplitude and phase errors and non-uniform noise on the array model are added, and a comprehensive observation model with clear distribution types of amplitude and phase errors, signals, and noise is established. The variational Bayesian inference theory is used to obtain closed solutions of various variables and parameters, so as to achieve joint estimation of target azimuth and error parameters. Simulation results and sea trial data processing results show that the algorithm can achieve amplitude and phase error self correction while completing DOA estimation in the absence of prior information on the number of sources.
Study on high-order-mode oscillation and migration characteristics of single bubble in the ultrasonic field
Authors: Huang Xiao , Niu Guang-Yun , Ren Chun-Zhu , Luo Xiao
Published: October 2024

Investigating the motion characteristics of cavitation bubbles in an ultrasonic field is important for industries such as ultrasonic cleaning and ultrasonic therapy. This paper investigated the oscillation and migration characteristics of a single cavitation bubble in a 20 kHz ultrasonic field. Peristaltic pump syringe injection tests were performed at different locations in a 20 kHz ultrasonic field, and a high-speed camera was used to observe the bubble motion characteristics. The bubble was found to resonate with the ultrasonic waves at a higher order mode, changing from spherical shape to honeycomb and golf ball shapes. Also, we found that the ultrasonic waves may prevent the buoyancy of the bubble. Through revealing the motion characteristics of the bubble in the ultrasonic field, we may control the bubble motion by ultrasonic, and strengthen the bubble cavitation effect.
Efficient numerical simulation method for nonlinear guided wave in frequency domain
Authors: Sun Chaoyu , Song Ailing , Xiang Yanxun
Published: October 2024

Nonlinear ultrasonic guided wave has attracted increasing attention for its ultra-sensitive to detect the incipient damages in service material by analyzing the amplitude of second harmonic wave. However, the mainstream method of simulating the second harmonic generation (SHG) in nonlinear material is using finite element method with time-domain solver, which is extremely time-consuming and can hardly simulate the huge and complex structures. In this paper, we propose a flexible finite element method based on frequency solver to simulate the SHG. The primary wave field, the second harmonic wave field and the static component field are separately set. This method is realized in Comsol Multiphysics software, the case of the SHG in plate indicates that the calculation efficiency has been significantly improved in compare with the time domain solver, whereas the results of time-domain solver and frequency domain solver have good agreement with each other. This method can be easily applied in the SHG analysis in huge and complex structures. Moreover, the primary wave field, the second harmonic wave field and the static component field can be respectively presented in the post-processing to help provide more information about physical insight of SHG.
On the cutoff, reappearance, and persistence of subsonic leaky A0 Lamb waves
Authors: Viggen E M , Arnestad H K
Published: October 2024

Subsonic leaky A0 Lamb waves, whose phase speeds are lower than the fluid’s sound speed, exhibit several peculiar behaviours. In this work, we investigate three such behaviours: Cutoff, where the A0 branch cuts off at some point in the subsonic domain, reappearance, where the cut-off A0 branch reappears at lower frequencies, and persistence, where the A0 branch is never cut off at all. From the literature, we take the case of a 1 mm thick aluminium plate immersed in air of varying density. We then analyse its exact leaky A0 wave solutions by means of a sound radiation model that takes energy conservation into account. This analysis explains these peculiar behaviours by connecting them with the conditions that allow sound-radiating subsonic leaky A0 Lamb waves.
Influence of polyethylene pipe butt fusion welding in ultrasonic non-destructive testing
Authors: An Bingwen , Li Ziqi , Li Feiran , Fang Xuefeng , Jiang Xueping , Leng Tao , Wu Xianmei
Published: October 2024

Butt fusion welding is a commonly used manufacturing method for polyethylene pipes. To investigate the influence of butt fusion welding on oblique ultrasonic wave in ultrasonic non-destructive testing, a numerical simulation model was established for polyethylene pipe with welding joints. Wave propagation in the polyethylene pipe was analysed, which showed that there exist longitudinal and shear waves propagating and their mode conversion. Detection signals of pipes with different defects and different acoustic attenuations were calculated. The special structure of welding joint was then modelled. Results show that the signal response declines with acoustic attenuation coefficient. Butt welding joints, especially the inner joints, would affect waves propagation. Finally, the welding process of polyethylene pipes was also simulated. The influence of cooling time was discussed, which indicated that insufficient cooling time would cause thermal residual stress and then alter the ultrasonic signal.
An exact analytical solution for coupled vibration analysis of a piezoelectric resonator
Authors: Ding Wenxiang , Li Liangtian , Wei Sheng , Bao Danyang , Zhou Hui , Sun Guodong
Published: October 2024

Piezoelectric resonators are widely used as the active components in devices such as sensors, actuators, communication filters, and micro/nano-electro-mechanical systems (MEMS / NEMS). Due to the piezoelectric effect, Poisson’s ratio, and its finite dimension, the thickness and lateral vibration modes in a piezoelectric resonator are inevitably coupled. In this paper, an exact analytical model for coupled vibration analysis of a piezoceramic disk is developed based on a new superstition method. The free vibrations are decomposed into thickness and lateral directions in a new form of Fourier-Bessel series and then they are superimposed to satisfy the boundary conditions. To verify the validity of the analytical model proposed here, numerical simulations are performed using COMSOL Multiphysics. An excellent agreement is observed. This analytical model can be applied to the design and optimization of piezoelectric devices.
Enhancing Alaskan wildfire prediction and carbon flux estimation: a two-stage deep learning approach within a process-based model
Authors: Seo Hocheol , Kim Yeonjoo
Published: October 2024

Wildfires in boreal forests release substantial amounts of carbon into the atmosphere. However, current land-surface models are limited in their representation of fire processes, including their ignition and spread. This study thus developed FireDL, a novel data-driven machine-learning model for the prediction of natural wildfires, and combined it with a land-surface model to better understand the impact of fire on carbon fluxes. FireDL has a two-stage deep learning structure that sequentially combines a long short-term memory (LSTM) algorithm and an artificial neural network (ANN). Preliminary random forest analysis identified fire duration as an important factor in predicting the burned area. Thus, in FireDL, the LSTM algorithm was employed to predict fire occurrence and duration, utilizing lightning, vegetation, and climate datasets. Subsequently, the ANN predicted the total burned area using the LTSM-derived fire duration predictions and climate datasets as input. FireDL produced a robust performance in predicting large fires (>10 000 ha), achieving a correlation coefficient of 0.72. The daily-scaled burned area predictions derived from FireDL were integrated into the Community Land Model version 5—Biogeochemistry (CLM5-BGC) to produce CLM5-BGC-FireDL. This integration considerably improved carbon emission estimations. Notably, the total net ecosystem exchange (NEE) estimated using CLM5-BGC-FireDL in 2019, the year with the highest recorded burned area during our study, was twice that estimated using the standard CLM5-BGC. Discrepancies in the NEE can significantly influence atmospheric CO2 levels, highlighting the importance of our fire prediction model in forecasting the burned area and carbon emissions. The use of FireDL with future climate scenarios is thus anticipated to yield valuable insights into ecosystem management and climate change mitigation strategies.
Hot isostatic pressing of ball milled novel grade high entropy alloys at different sintering time and the investigation of their mechanical and corrosion resistance properties
Authors: Rajendrachari Shashanka , Altas Emre , Salunkhe Sachin , Dag Ilker Emin , Avar Baris , Chaira Debasis
Published: October 2024

With the discovery of high entropy alloys, new materials with superior properties have emerged. According to recent research, high-entropy alloys’ multi-component structure and mixing entropy have made them more prominent than other alloys. Because of their excellent chemical and mechanical properties—such as high hardness, high-temperature resistance, high wear resistance, chemical stability, and high corrosion resistance—high entropy alloys outperform other material types in various applications. A new grade of mechanically alloyed high entropy alloy (HEA) of composition 23Fe-21Cr-18Ni-20Ti-18Mn was consolidated by a hot isostatic pressing (HIP) at a temperature of 1000 °C, at different sintering time of 30, 60, and 90 min respectively. We have investigated the impact of sintering time on the microstructure, mechanical, corrosion, and wear-resistance properties. The x-ray diffraction (XRD) spectra of the 30 min HIPed HEA sample showed dominant s-FeCr phases and traces of γ-Fe, and the Ni-Ti phases. Whereas, the 90 min HIPed HEA samples showed more dominant Ni-Ti and traces of γ-Fe, and β-Mn phases. There is a phase transformation from BCC to HCP of consolidated HEA at increased holding time. The density of the samples increases from 5.882 to 6.327 g cm−3 and the porosity percentage decreases from 12.93 to 6.35% with the increase in the holding time. The Vickers microhardness value for 30, 60, and 90 min HIPed 23Fe-21Cr-18Ni-20Ti-18Mn HEA at 1000 °C was found to be 433, 513, and 793 HV respectively at an indentation load of 0.1 kgf. The consolidated HEA sample undergoes an abrasive and oxidative wear mechanism with ploughing and plastic deformation modes. The morphology of the wear debris was investigated using SEM. The 90 min sintered sample showed an excellent corrosion resistance due to the high rate of material densification and minimum surface flaws.
Synthesis and antimicrobial activity of yttrium-doped cerium oxide nano-composite against wound pathogen
Authors: Saha Anisha , Devanand Venkatasubbu G , Sheik Mohideen Sahabudeen
Published: October 2024

Nanocomposite materials have attracted considerable interest in several disciplines owing to their distinctive characteristics and possible uses. The primary objective of this study was to synthesize and characterize a nanocomposite material consisting of cerium that has been doped with yttrium. The shape, structure, and properties of the synthesized nanocomposite was characterized using various characterization techniques including ultraviolet spectrophotometry, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), x-ray diffraction (XRD), zeta potential measurements, dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR).The antibacterial activity of the nanocomposite was assessed against a range of pathogenic bacteria including Gram-positive bacteria - Enterococcus faecalis, Staphylococcus aureus, and Gram-negative bacteria- Escherichia coli, Pseudomonas aeruginosa using standard microbiological techniques. The results indicate that the nanocomposite possesses strong antibacterial properties against a wide range of microorganisms, showcasing its potential as a highly effective antimicrobial agent for diverse applications in the biological, environmental, and industrial fields. Hemolysis is the process of red blood cell destruction, resulting in the release of hemoglobin into the surrounding fluid. In this study, 0.7:0.3M nanocomposite had showed effective biocompatibility with less than 5%. Furthermore, this particular composite remained identical in different time intervals, while other composites would normally fluctuate. Research has shown that meticulous material design and surface modification can reduce the harmful effects on red blood cells, hence improving the safety of nanocomposite for therapeutic purposes. In summary, this study offers valuable information on the creation, analysis, and assessment of nanocomposite materials with antimicrobial properties.
Writing Mad Lives in the Age of the Asylum
Authors: Rembis Michael
Published: October 2024

Using the writing of former asylum inmates, as well as other sources, Writing Mad Lives in the Age of the Asylum reveals a history of madness and the asylum that has remained hidden by a focus on doctors, diagnoses, and other interventions into mad people’s lives. Although those details are present in this story, its focus is the hundreds of inmates who spoke out or published pamphlets, memorials, memoirs, and articles about their experiences. They recalled physical beatings and prolonged restraint and isolation. They described what it felt like to be gawked at like animals by visitors and the hardships they faced re-entering the community. They also spoke about the friendships forged among asylum inmates, many of which persisted after mad people left the asylum. Many inmates argued that asylums were more akin to prisons than medical facilities and testified before state legislatures and the US Congress, lobbying for reforms to what became popularly known as “lunacy laws.” Writing Mad Lives in the Age of the Asylum exposes the centrality of changing and conflicting relations of care in producing wider ideological and systemic shifts in the history of madness – a process in which the individual and collective efforts of ordinary people shaped structures and cultures much larger than themselves.
Epilogue
Authors: Rembis Michael
Published: October 2024

The epilogue contemplates the importance of using a critical analysis of storytelling in the history of madness and asylums and in more recent efforts to challenge the growing global dominance of biopsychiatric definitions of and treatments for mental troubles and distress. It argues that storytelling is vital to the human experience and that a critical analysis of storytelling is an underutilized methodology in the history of madness and mad people. Mad people have, for centuries, used stories to make sense of their experiences, to talk back to an expanding scientific medical establishment, and to gain allies in their fight for social and political change. Physicians, on the other hand, have also used stories to bolster a particular—although historically contingent and changing—medicalized understanding of madness and its treatment. When historians and other scholars critically engage with stories and storytelling in the history of madness, they can move toward a more inclusive and socially just rendering of this essential yet often stigmatized and misrepresented aspect of the human experience.
IPFMC: an iterative pathway fusion approach for enhanced multi-omics clustering in cancer research
Authors: Zhang Haoyang , Liu Sha , Li Bingxin , Zhou Xionghui
Published: October 2024

Using multi-omics data for clustering (cancer subtyping) is crucial for precision medicine research. Despite numerous methods having been proposed, current approaches either do not perform satisfactorily or lack biological interpretability, limiting the practical application of these methods. Based on the biological hypothesis that patients with the same subtype may exhibit similar dysregulated pathways, we developed an Iterative Pathway Fusion approach for enhanced Multi-omics Clustering (IPFMC), a novel multi-omics clustering method involving two data fusion stages. In the first stage, omics data are partitioned at each layer using pathway information, with crucial pathways iteratively selected to represent samples. Ultimately, the representation information from multiple pathways is integrated. In the second stage, similarity network fusion was applied to integrate the representation information from multiple omics. Comparative experiments with nine cancer datasets from The Cancer Genome Atlas (TCGA), involving systematic comparisons with 10 representative methods, reveal that IPFMC outperforms these methods. Additionally, the biological pathways and genes identified by our approach hold biological significance, affirming not only its excellent clustering performance but also its biological interpretability.
Genitourinary disorders and oral medicine
Authors: Ramar Sree Yazhini , Kotekar Sanjana , Sivakumar Aravind , Kumar Sheetanshu
Published: October 2024

We report a 36-year-old man who presented with painless oral erosions and plaques.
A network analysis of affective and motivational individual differences and error monitoring in a non-clinical sample
Authors: Grabowska Anna , Sondej Filip , Senderecka Magdalena
Published: October 2024

Error monitoring, which plays a crucial role in shaping adaptive behavior, is influenced by a complex interplay of affective and motivational factors. Understanding these associations often proves challenging due to the intricate nature of these variables. With the aim of addressing previous inconsistencies and methodological gaps, in this study, we utilized network analysis to investigate the relationship between affective and motivational individual differences and error monitoring. We employed six Gaussian Graphical Models on a non-clinical population ($N$ = 236) to examine the conditional dependence between the amplitude of response-related potentials (error-related negativity; correct-related negativity) and 29 self-report measures related to anxiety, depression, obsessive thoughts, compulsive behavior, and motivation while adjusting for covariates: age, handedness, and latency of error-related negativity and correct-related negativity. We then validated our results on an independent sample of 107 participants. Our findings revealed unique associations between error-related negativity amplitudes and specific traits. Notably, more pronounced error-related negativity amplitudes were associated with increased rumination and obsessing, and decreased reward sensitivity. Importantly, in our non-clinical sample, error-related negativity was not directly associated with trait anxiety. These results underscore the nuanced effects of affective and motivational traits on error processing in healthy population.
Head to head comparison of left atrial and ventricular strain at rest in prediction of exercise induced elevated left ventricular filling pressure
Authors: Takagi T
Published: October 2024

Background

Both left atrial (LA) and ventricular (LV) strain at rest have been reported as predictors of exercise induced elevated LV filling pressure. However, head to head comparison of LA and LV strain is very limited. The purpose of this study was to compare peak atrial longitudinal stain (PALS) and LV global longitudinal strain (GLS) in prediction of exercise induced elevated LV filling pressure.

Methods

From January 2018 to December 2022, 286 consecutive patients underwent treadmill stress echocardiography. Patients with atrial fibrillation, E/e’ ≥ 15 at rest, and LV ejection fraction < 50% were excluded from the study, and 217 patients were recruited. All patients underwent routine echocardiography including PALS and GLS measurements. Exercise induced elevated LV filling pressure was defined as post-exercise septal E/e’ ≥ 15.

Results

Both PALS and GLS were obtained in 212 patients, and 50 patients had post-exercise E/e’ ≥ 15. Receiver oriented curve analysis revealed best cutoff value of 23.9% for PALS (sensitivity 68%, specificity 67%, respectively) and -17.7% for GLS (sensitivity 84%, specificity 65%, respectively) in prediction of post-exercise E/e' ≥15. Univariate logistic analysis demonstrated that impaired PALS, impaired GLS and raised E/e’ at rest were associated with post-exercise E/e’ ≥ 15. However, multivariate logistic analysis revealed that GLS and E/e’ were independent predictors of post-exercise E/e’ ≥ 15, but PALS was not.

Conclusions

Both impaired PALS and GLS at rest can predict post-exercise E/e’ ≥ 15.0. However, multivariate logistic analysis has demonstrated that impaired GLS, not PALS was independent predictor of exercise induced elevated LV filling pressure.
Left atrial longitudinal strain behavior in patients with cryptogenic stroke - a case control study
Authors: Bigdelu L , Maadarani O , Baghestani Z , Jafari O , Bitar Z
Published: October 2024

Background

A significant percentage of ischemic strokes classified as cryptogenic stroke (CS) where the definition is varied according to the type of classification used. Left atrial (LA) function has a role in determining the possible cardio-embolic source of stroke. Using speckle tracking transthoracic echocardiography (TTE) we can detect the early changes in left atrial function by measuring left atrial longitudinal strain (LALS).

Aim

To evaluate the left atrial stain in patients with a cryptogenic stroke as compared to a healthy papulation.

Method and results

We recruited 50 cryptogenic ischemic stroke patients with mean age of 44.7 years and 50 % were male who treated consecutively as for first CS, and 50 age-and sex-matched healthy stroke-free controls. Using Speckle tracking TTE analysis we measured the global , passive and active longitudinal LA strain corresponding to the reservoir (LASRES), conduit(LASCD), and contractile function(LASCT),respectively in addition to standard other LA parameters and filling pressure parameters of Left ventricle(LV) in both group. Data were compared using t-test and Mann-Whitney test. Cryptogenic stroke patients as compared with controls had significantly reduced value of all components of LALS [Mean value of LASRES, LASCD and LASCT in CS group versus control group were 25.15±6.79 versus 43.95±4.62 (P-value <0.01), 14.41±3.53 versus 25.68±3.30 (P- value <0.01), 10.73±3.35 versus 18.28±1.60 (P-value <0.01) respectively] (Figure 1 and Figure 2). There were no significant differences in means of LA area and LA volume index in both groups (P value >0.05). Between parameters of LV filling pressures, it was noticed that early diastolic transmitral flow velocity (E) and early diastolic velocity at annulus (E’) were statistically lower in CS patients as compared to control group (P-value <0.01). In addition, the Cluster and Discriminant analysis used confirmed that LASRES, LASCD and LASCT were significantly lower in value in cryptogenic stroke patients in comparison to Control group which can be used to detect early LA dysfunction.

Conclusion

LA longitudinal strain in all components were significantly impaired in patients with CS. Measuring LALS parameters can be useful in determining early LA dysfunction in cryptogenic stroke patients.Figure 1-left atrial strain components.Figure 2 -left atrial strain component.
Diagnostic value of aortic valve displacement by tissue tracking for identification of aortic valve stenosis severity
Authors: Jasinska A , Zakrzewski D , Hryniewiecki T , Stoklosa P
Published: October 2024

Background

The assessment of aortic stenosis (AS) severity on transthoracic echocardiography (TTE) may be challenging, especially in normal flow, low gradient (NF LG) group with preserved ejection fraction (EF), where reclassification of AS severity after initial TTE was observed in 52% pts (1). Calcifications and fibrosis of valve leaflets result in increased stiffness and impaired mobility, which can be quantified by tissue tracking (TT). TT is an echocardiographic modality that displays longitudinal displacement of selected area by integrating tissue velocity over time.

Purpose

Assessment of the diagnostic value of aortic valve displacement (AVD) by TT as a test that may increase accuracy of AS severity diagnosis in TTE.

Methods

205 pts (aged 71±10 yrs, men 43%) without more than mild aortic regurgitation, mitral or tricuspid valve disease, EF ≤55%, indexed stroke volume (SVI) ≤35 ml/m2, cardiac rhythm disturbances and poor acoustic window were selected out of 842 pts screened for AS in our institution between 2020 and 2023. Based on aortic valve area (AVA) value, moderate (n=51, AVA >1.0 cm2) or severe (n=154, AVA ≤1.0 cm2) AS was diagnosed. In severe AS group, 45 pts were classified as NF LG AS (mean gradient <40 mmHg). Additionally 30 pts (aged 68±10 yrs, men 46%) without abnormalities on TTE entered control group. During TTE in five- and three-chamber views, TT was applied and region of interest was adjusted to cover whole aortic valve (AV) during cardiac cycle.

Single loop was analysed with Q-analysis software. The measurement in millimetres (mm) of positive wave representing displacement of AV was performed in both views by two independent echocardiographers (Figure 1). AVD was calculated by summing up results from both views. Receiver-operating characteristic curves for AVD in the whole study group and NF LG AS to diagnose severe AS were plotted.

Results

AVD was already significantly decreased in moderate AS compared with age- and sex-matched healthy controls, being 22.8±2.8 mm and 24.3±2.1 mm respectively (P=0.01). In pts with severe AS, AVD was further significantly reduced compared to moderate AS pts, being 19.3±3.2 mm (P<0.0001). In the whole study group, AVD with a cut-off point <19.6 mm provided 55.8% sensitivity but 96.1 % specificity to diagnose severe AS (Figure 2B). In pts with NF LG AS, AVD with a cut-off point <20.6 mm provided 71.4% sensitivity and a specificity of 79.6% (Figure 2A). Intraclass correlation coefficient of 0.87; 95% CI (0.84–0.89) indicated good interobserver reproducibility of AVD measurement.

Conclusions

Aortic valve displacement by tissue tracking in TTE is a valuable, new echocardiographic tool for identification of AS severity and may improve diagnostic accuracy of AS severity in NF LG AS.Figure 1Figure 2