scholarly journals Monitoring and Detecting Fouled Ballast Using Forward-Looking Infrared Radiometer (FLIR) Aerial Technology: Possibilities and Limitations

2019 ◽  
Author(s):  
Yongwen Tan ◽  
Yang Chen ◽  
Andrew W. Peterson ◽  
Mehdi Ahmadian
Keyword(s):  
Fine Particles ◽  
Early Stage ◽  
Imaging Techniques ◽  
Thermal Characteristics ◽  
Rolling Stock ◽  
Test Results ◽  
Railway Ballast ◽  
Fouled Ballast ◽  
Infrared Radiometer ◽  
Forward Looking

This paper examines the feasibility and limitations of Forward Looking Infrared Radiometer (FLIR) Aerial Technology for detecting fouled ballast. The method is intended to provide an efficient and ready-to-use approach that can help the railroads detect fouled ballast in their early stages. Ballast fouling commonly occurs as a result of fine particles clogging off water passage through them. Subsequently, this results in trapped water that often results in poor foundation strength, rotting of the ties, and other ill effects. This study includes a novel approach to evaluate the railway ballast fouling by using thermal imaging techniques. In particular, the thermal characteristics of clean and fouled ballast are studied using FLIR cameras that can be used onboard rolling stock, Hyrail trucks, or drones. Laboratory tests are primarily performed to measure the surface temperature changing rate of clean and fouled ballast in response to ambient temperature changes. For the purpose of laboratory testing, the camera is set up in stationary and moving configurations. The test results indicate that clean and fouled ballast have different thermal characteristics. In particular, different thermal patterns are obtained during naturally-occurring daily temperature change. The test results also indicate that the FLIR cameras can be used on a moving platform for quick scanning of thermal images of the ballast that could be used for assessing the early stage of fouling.

scholarly journals Impact of Ballast Fouling on the Mechanical Properties of Railway Ballast: Insights from Discrete Element Analysis

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1331
Author(s):  
Luyu Wang ◽  
Mohamed Meguid ◽  
Hani S. Mitri
Keyword(s):  
Shear Strength ◽  
Mechanical Response ◽  
Fine Particles ◽  
Element Model ◽  
Discrete Element ◽  
Shear Loading ◽  
Discrete Element Model ◽  
Railway Ballast ◽  
Fouled Ballast ◽  
Interparticle Friction

Ballast fouling is a major factor that contributes to the reduction of shear strength of railway ballast, which can further affect the stability of railway supporting structure. The major sources of ballast fouling include infiltration of foreign fines into the ballast material and ballast degradation induced by train movement on the supported tracks. In this paper, a discrete element model is developed and used to simulate the shear stress–strain response of fouled ballast assembly subjected to direct shear loading. A simplified computational approach is then proposed to model the induced ballast fouling and capture the mechanical response of the ballast at various levels of contamination. The approach is based on the assumption that fine particles comprising the fouling material will not only change the interparticle friction angle, but also the contact stiffness between the ballast particles. Therefore, both the interparticle friction coefficient and effective modulus are adjusted based on a fouled ballast model that is validated using experimental results. The effect of ballast degradation is also investigated by gradually changing the particle size distribution of the ballast assembly in the discrete element model to account for the increased range of particle sizes. Using the developed model, the effect of ballast degradation on the shear strength is then evaluated. Conclusions are made to highlight the suitability of these approximate approaches in efficiently modeling ballast assemblies under shear loading conditions.

Twin boundary structure of a Y-Ba-Cu-O superconductor

1989 ◽  
Vol 47 ◽  
pp. 168-169
Author(s):  
Yimei Zhu ◽  
Masaki Suenaga ◽  
R. L. Sabatini ◽  
Youwen Xu
Keyword(s):  
Twin Boundary ◽  
Fine Particles ◽  
Imaging Techniques ◽  
Fine Powder ◽  
Orthorhombic Phase ◽  
Boundary Structure ◽  
Crystallographic Axis ◽  
System A ◽  
High Resolution Structure ◽  
Electron Microscopes

The (110) twin structure of YBa2Cu3O7 superconductor oxide, which is formed to reduce the strain energy of the tetragonal to orthorhombic phase transformation by alternating the a-b crystallographic axis across the boundary, was extensively investigated. Up to now the structure of the twin boundary still remained unclear. In order to gain insight into the nature of the twin boundary in Y-Ba-Cu-O system, a study using electron diffraction techniques including optical and computed diffractograms, as well as high resolution structure imaging techniques with corresponding computer simulation and processing was initiated.Bulk samples of Y-Ba-Cu-O oxide were prepared as described elsewhere. TEM specimens were produced by crushing bulk samples into a fine powder, dispersing the powder in acetone, and suspending the fine particles on a holey carbon grid. The electron microscopy during this study was performed on both a JEOL 2000EX and 2000FX electron microscopes operated at 200 kV.

Brain Tumor Detection via Asymmetry Quantification across Mid Sagittal Plane

2020 ◽  
Vol 13 ◽  
Author(s):  
Shoaib Amin Banday ◽  
Mohammad Khalid Pandit
Keyword(s):  
Brain Tumor ◽  
Brain Tumors ◽  
Sagittal Plane ◽  
Early Stage ◽  
Imaging Techniques ◽  
Complex Structure ◽  
Magnetic Resonance Images ◽  
Absolute Difference ◽  
Brain Hemispheres ◽  
The Brain

Introduction: Brain tumor is among the major causes of morbidity and mortality rates worldwide. According to National Brain Tumor Foundation (NBTS), the death rate has nearly increased by as much as 300% over last couple of decades. Tumors can be categorized as benign (non-cancerous) and malignant (cancerous). The type of the brain tumor significantly depends on various factors like the site of its occurrence, its shape, the age of the subject etc. On the other hand, Computer Aided Detection (CAD) has been improving significantly in recent times. The concept, design and implementation of these systems ascend from fairly simple ones to computationally intense ones. For efficient and effective diagnosis and treatment plans in brain tumor studies, it is imperative that an abnormality is detected at an early stage as it provides a little more time for medical professionals to respond. The early detection of diseases has predominantly been possible because of medical imaging techniques developed from past many decades like CT, MRI, PET, SPECT, FMRI etc. The detection of brain tumors however, has always been a challenging task because of the complex structure of the brain, diverse tumor sizes and locations in the brain. Method: This paper proposes an algorithm that can detect the brain tumors in the presence of the Radio-Frequency (RF) inhomoginiety. The algorithm utilizes the Mid Sagittal Plane as a landmark point across which the asymmetry between the two brain hemispheres is estimated using various intensity and texture based parameters. Result: The results show the efficacy of the proposed method for the detection of the brain tumors with an acceptable detection rate. Conclusion: In this paper, we have calculated three textural features from the two hemispheres of the brain viz: Contrast (CON), Entropy (ENT) and Homogeneity (HOM) and three parameters viz: Root Mean Square Error (RMSE), Correlation Co-efficient (CC), and Integral of Absolute Difference (IAD) from the intensity distribution profiles of the two brain hemispheres to predict any presence of the pathology. First a Mid Sagittal Plane (MSP) is obtained on the Magnetic Resonance Images that virtually divides brain into two bilaterally symmetric hemispheres. The block wise texture asymmetry is estimated for these hemispheres using the above 6 parameters.

Whole brain atlas-based diffusion kurtosis imaging parameters for evaluation of minimal hepatic encephalopathy

2021 ◽  
pp. 197140092110269
Author(s):  
Prateek Gupta ◽  
Sameer Vyas ◽  
Teddy Salan ◽  
Chirag Jain ◽  
Sunil Taneja ◽  
...  
Keyword(s):  
Hepatic Encephalopathy ◽  
Clinical Symptoms ◽  
Early Stage ◽  
Imaging Techniques ◽  
Clinical Stage ◽  
Minimal Hepatic Encephalopathy ◽  
Brain Atlas ◽  
Diffusion Kurtosis Imaging ◽  
Whole Brain ◽  
Diffusion Kurtosis

Background and purposes Minimal hepatic encephalopathy (MHE) has no recognizable clinical symptoms, but patients have cognitive and psychomotor deficits. Hyperammonemia along with neuroinflammation lead to microstructural changes in cerebral parenchyma. Changes at conventional imaging are detected usually at the overt clinical stage, but microstructural alterations by advanced magnetic resonance imaging techniques can be detected at an early stage. Materials and methods Whole brain diffusion kurtosis imaging (DKI) data acquired at 3T was analyzed to investigate microstructural parenchymal changes in 15 patients with MHE and compared with 15 age- and sex-matched controls. DKI parametric maps, namely kurtosis fractional anisotropy (kFA), mean kurtosis (MK), axial kurtosis (AK) and radial kurtosis (RK), were evaluated at 64 white matter (WM) and gray matter (GM) regions of interest (ROIs) in the whole brain and correlated with the psychometric hepatic encephalopathy score (PHES). Results The MHE group showed a decrease in kFA and AK across the whole brain, whereas MK and RK decreased in WM ROIs but increased in several cortical and deep GM ROIs. These alterations were consistent with brain regions involved in cognitive function. Significant moderate to strong correlations (–0.52 to –0.66; 0.56) between RK, MK and kFA kurtosis metrics and PHES were observed. Conclusion DKI parameters show extensive microstructural brain abnormalities in MHE with minor correlation between the severity of tissue damage and psychometric scores.

scholarly journals Micro-mechanical investigation of railway ballast behavior under cyclic loading in a box test using DEM: effects of elastic layers and ballast types

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Nishant Kumar ◽  
Bettina Suhr ◽  
Stefan Marschnig ◽  
Peter Dietmaier ◽  
Christof Marte ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Early Stage ◽  
Damage Model ◽  
Simulation Models ◽  
Railway Track ◽  
Maintenance Cost ◽  
Particle Movement ◽  
Railway Ballast ◽  
Elastic Layers ◽  
The Impact

Abstract Ballasted tracks are the commonly used railway track systems with constant demands for reducing maintenance cost and improved performance. Elastic layers are increasingly used for improving ballasted tracks. In order to better understand the effects of elastic layers, physical understanding at the ballast particle level is crucial. Here, discrete element method (DEM) is used to investigate the effects of elastic layers – under sleeper pad ($$\text {USP}$$USP) at the sleeper/ballast interface and under ballast mat ($$\text {UBM}$$UBM) at the ballast/bottom interface – on micro-mechanical behavior of railway ballast. In the DEM model, the Conical Damage Model (CDM) is used for contact modelling. This model was calibrated in Suhr et al. (Granul Matter 20(4):70, 2018) for the simulation of two different types of ballast. The CDM model accounts for particle edge breakage, which is an important phenomenon especially at the early stage of a tamping cycle, and thus essential, when investigating the impact of elastic layers in the ballast bed. DEM results confirm that during cyclic loading, $$\text {USP}$$USP reduces the edge breakage at the sleeper/ballast interface. On the other hand, $$\text {UBM}$$UBM shows higher particle movement throughout the ballast bed. Both the edge breakage and particle movement in the ballast bed are found to influence the sleeper settlement. Micro-mechanical investigations show that the force chain in deeper regions of the ballast bed is less affected by $$\text {USP}$$USP for the two types of ballast. Conversely, dense lateral forces near to the box bottom were seen with $$\text {UBM}$$UBM. The findings are in good (qualitative) agreement with the experimental observations. Thus, DEM simulations can aid to better understand the micro-macro phenomena for railway ballast. This can help to improve the track components and track design based on simulation models taking into account the physical behavior of ballast. Graphical Abstract

Measurement and Analysis on Transient Thermal Characteristics of High Speed Motorized Spindle

2011 ◽  
Vol 52-54 ◽  
pp. 2021-2026
Author(s):  
Gui Ling Deng ◽  
Can Zhou
Keyword(s):  
High Speed ◽  
Thermal Deformation ◽  
Thermal Characteristics ◽  
Measuring System ◽  
Test Results ◽  
Motorized Spindle ◽  
Measurement And Analysis ◽  
Turning Center ◽  
Transient Thermal ◽  
Deformation Compensation

Thermal deformation is an important factor to affect the accuracy of the motorized spindle, the core component of high-speed machine tool. To understand the spindle system transient thermal characteristics of the high-speed turning center CH7516GS, some high-precision sensors and high-frequency data acquisition system is used to establish the temperature and displacement measuring system. The thermal deformation compensation model is established on the basis of the experimental test results.

Clinical Stage I Carcinoma of the Uterine Cervix Value of Preoperative Magnetic Resonance Imaging in Assessing Parametrial Invasion

2002 ◽  
Vol 88 (4) ◽  
pp. 291-295 ◽  
Author(s):  
Sandro Sironi ◽  
Massimo Bellomi ◽  
Gaetano Villa ◽  
Silvia Rossi ◽  
Alessandro Del Maschio
Keyword(s):  
Cervical Cancer ◽  
Mr Imaging ◽  
Tumor Invasion ◽  
Early Stage ◽  
Imaging Techniques ◽  
Clinical Stage ◽  
Fast Spin Echo ◽  
Parametrial Invasion ◽  
Early Stage Cervical Cancer ◽  
T2 Weighted Images

Aims and Background The purpose of this prospective study was to assess the efficacy of different MR imaging techniques in the evaluation of parametrial tumor invasion in patients with early stage cervical cancer. Methods A total of 73 consecutive patients, clinically considered to have invasive tumor (<3 cm in diameter) confined to the cervix, underwent MR imaging studies at 1 T, according to the following protocol: fast spin-echo (FSE) T2-weighted, gadolinium-enhanced SE T1-weighted, and fat-suppressed gadolinium-enhanced SE T1-weighted sequences. Images obtained with each sequence were evaluated for parametrial invasion with the use of histopathologic findings as the standard of reference. Results In the assessment of tumor infiltration of the parametrium, with FSE T2-weighted images accuracy was 83%, with SE T1-weighted gadolinium-enhanced images was 65%, and with SE T1-weighted gadolinium-enhanced fat-suppressed images was 72%. The difference between the accuracy rate achieved with FSE T2-weighted images and those obtained with the other two MR sequences was statistically significant (P <0.05). The high negative predictive value (95%) for the exclusion of parametrial tumor invasion was the principal contributor to the staging accuracy obtained with FSE T2-weighted imaging. Conclusions Unenhanced FSE T2-weighted imaging is a reliable method for determining the degree of tumor invasion in patients with early stage cervical cancer. Our data suggest that contrast-enhanced sequences, even with the use of the fat suppression technique, have limited value in assessing tumor extension.

Virus induced hepatocellular carcinoma (HCC) and protein biomarkers

2021 ◽  
Author(s):  
Hamza Abbas Jaffari ◽  
Sumaira Mazhar
Keyword(s):  
Hepatocellular Carcinoma ◽  
Early Stage ◽  
Imaging Techniques ◽  
Disease Diagnosis ◽  
Protein Biomarkers ◽  
Early Disease ◽  
Detection Systems ◽  
Non Invasive ◽  
Viral Hepatitis B ◽  
Current Article

Hepatocellular carcinoma (HCC) is a standout amongst the most widely recognized cancers around the world, and just as the alcoholic liver disease it is also progressed by extreme viral hepatitis B or C. At the early stage of the disease, numerous patients are asymptomatic consequently late diagnosis of HCC occurs resulting in expensive surgical resection or transplantation. On the basis of the alpha fetoprotein (AFP) estimation, combined with the ultrasound and other sensitive imaging techniques used, the non-invasive detection systems are available. For early disease diagnosis and its use in the effective treatment of HCC patients, the identification of HCC biomarkers has provided a breakthrough utilizing the molecular genetics and proteomics. In the current article, most recent reports on the protein biomarkers of HBV or HCV-related HCC and their co-evolutionary association with liver cancer are reviewed.

scholarly journals Relationship between Students’ Diagnostic Assessment and Achievement in a Pre-University Mathematics Course

2017 ◽  
Vol 6 (4) ◽  
pp. 364 ◽  
Author(s):  
George Tan Geok Shim ◽  
Abang Mohammad Hudzaifah Abang Shakawi ◽  
Farah Liyana Azizan
Keyword(s):  
Diagnostic Test ◽  
Early Stage ◽  
Teaching Style ◽  
Basic Knowledge ◽  
Local Context ◽  
Strong Positive Correlation ◽  
Test Results ◽  
Mathematical Concepts ◽  
University Mathematics ◽  
Mathematics Examination

Educators have always highlighted the importance of mathematics mastery in education for many years. With the current emphasis of Science, Technology, Engineering and Mathematics (STEMs) education, mathematics mastery is even more vital because it supports the learning and mastery of science fields such as engineering and science. Furthermore, in higher education, mathematics is essential because majority of the courses require the use of mathematical concepts in their learning. In recent years, many countries including Malaysia have seen an increase in the enrolment number of tertiary students. The increase in student enrolment has resulted in a population of students with diverse abilities, and this creates challenges for educators in providing instruction to the students. Educators need to detect students’ mathematical ability at an early stage before teaching them new content. One way to gather information about students’ basic mathematics skill is through the use of diagnostic test. Diagnostic test in education is a preliminary assessment mainly used to detect students’ strengths and weaknesses in learning. It allows educators to cater their teaching style and content to suit to the students’ basic knowledge. With researches indicating the importance and benefits of using diagnostic test in various subjects, it is important to further examine the use of diagnostic test in the local context of pre-university studies. This study investigated the relationship between students’ mathematics diagnostic test results and final mathematics examination performances at a public pre-university programme. The samples of the study consisted of 250 pre-university students and the data of the study were collected through a mathematics diagnostic test paper, a questionnaire and a final mathematics examination. The outcomes of the study show that there was a strong positive correlation between mathematics diagnostic test results and students’ mathematics achievement in pre-university.

scholarly journals Carbon Based Nanodots in Early Diagnosis of Cancer

2021 ◽  
Vol 9 ◽  
Author(s):  
Gurpal Singh ◽  
Harinder Kaur ◽  
Akanksha Sharma ◽  
Joga Singh ◽  
Hema Kumari Alajangi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Early Stage ◽  
Imaging Techniques ◽  
Graphene Quantum Dots ◽  
Carbon Quantum Dots ◽  
Diagnostic Methods ◽  
Early Diagnosis Of Cancer ◽  
Successful Treatment Outcome ◽  
Wide Range ◽  
Carbon Based

Detection of cancer at an early stage is one of the principal factors associated with successful treatment outcome. However, current diagnostic methods are not capable of making sensitive and robust cancer diagnosis. Nanotechnology based products exhibit unique physical, optical and electrical properties that can be useful in diagnosis. These nanotech-enabled diagnostic representatives have proved to be generally more capable and consistent; as they selectively accumulated in the tumor site due to their miniscule size. This article rotates around the conventional imaging techniques, the use of carbon based nanodots viz Carbon Quantum Dots (CQDs), Graphene Quantum Dots (GQDs), Nanodiamonds, Fullerene, and Carbon Nanotubes that have been synthesized in recent years, along with the discovery of a wide range of biomarkers to identify cancer at early stage. Early detection of cancer using nanoconstructs is anticipated to be a distinct reality in the coming years.

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