scholarly journals PERFORMANCE EVALUATION OF RAILWAY BALLAST DEGRADATION USING THE MORPHOLOGICAL PROPERTIES

2021 ◽  
Vol 15 (2) ◽  
pp. 150-161
Author(s):  
Ashiru Mohammed ◽  
Ibrahim Aliyu ◽  
Hussaini Abdullahi Umar ◽  
Aliyu Umar Mani

Ballast degradation through attrition and breakage during operations affects the structural performance of the railway track system. In an attempt to study railway ballast degradation changes due to train cyclic loading at micro-scale. This study quantified and compared the changes that occur on ballast particles due to ballast degradation using LAA test and image analysis techniques. TB/T 2328.14-2008 gradation use by china railways was adopted. Series of LAA tests were conducted to accelerate the ballast particle breakage and abrasion, in a sequence of 250 turns of the LAA test drum, after which the changes in gradation and morphological properties were quantified. The morphological properties were quantified using imaging techniques (Aggregate Image measurement system (AIMS)). At the end of the study, the overall results showed that ballast degradation has a strong correlation with the ballast particle's morphological properties. The relationships and the indices of morphological changes can be used for numerical modeling and simulations using discrete element method (DEM) to study the performance of ballast at different degradation levels.

Author(s):  
Mukhil Azhagan M. S ◽  
Dhwani Mehta ◽  
Hangwei Lu ◽  
Sudarshan Agrawal ◽  
Mark Tehranipoor ◽  
...  

Abstract Globalization and complexity of the PCB supply chain has made hardware assurance a challenging task. An automated system to extract the Bill of Materials (BoM) can save time and resources during the authentication process, however, there are numerous imaging modalities and image analysis techniques that can be used to create such a system. In this paper we review different imaging modalities and their pros and cons for automatic PCB inspection. In addition, image analysis techniques commonly used for such images are reviewed in a systematic way to provide a direction for future research in this area. Index Terms—Component Detection, PCB, Authentication, Image Analysis, Machine Learning


Agriculture ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 112 ◽  
Author(s):  
Andrzej Przybylak ◽  
Radosław Kozłowski ◽  
Ewa Osuch ◽  
Andrzej Osuch ◽  
Piotr Rybacki ◽  
...  

This paper describes the research aimed at developing an effective quality assessment method for potato tubers using neural image analysis techniques. Nowadays, the methods used to identify damage and diseases are time-consuming, require specialized knowledge, and often rely on subjective judgment. This study showed the use of the developed neural model as a tool supporting the evaluation of potato tubers during the sorting process in the storage room.


Author(s):  
Ryota Tsubaki ◽  
Koji Ichii ◽  
Jeremy D. Bricker ◽  
Yoshihisa Kawahara

Abstract. Fragility curves evaluating risk of railway track ballast and embankment fill scour were developed. To develop fragility curves, two well-documented single-track railway washouts during two recent floods in Japan were investigated. Type of damage to the railway was categorized into no damage, ballast scour, and embankment scour, in order of damage severity. Railway overtopping surcharge for each event was estimated via hydrologic and hydraulic analysis. Normal and log-normal fragility curves were developed based on failure probability derived from field records. A combined ballast and embankment scour model was validated by comparing the spatial distribution of railway scour with the field damage record.


Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 926
Author(s):  
Toshio Fumoto ◽  
Shouhei Kinoshita ◽  
Takao Sasaki ◽  
Norihito Shimamura ◽  
Hiroki Ohkuma

Vascular tortuosity is associated with various disorders and is being increasingly detected through advances in imaging techniques. The underlying mechanisms for vascular tortuosity, however, remain unclear. Here, we tested the hypothesis that oxidative stress mediates the generation of tortuous vessels. We used the bilateral common carotid artery (CCA) ligation model to induce vascular tortuosity. Both young and adult rats showed basilar artery tortuous morphological changes one month after bilateral CCA ligation. These tortuous changes were permanent but more pronounced in the adult rats. Microarray and real-time PCR analysis revealed that these tortuous changes were accompanied by the induction of oxidative stress-related genes. Moreover, the indicated model in rabbits showed that tortuous morphological changes to the basilar artery were suppressed by antioxidant treatment. These results are highly suggestive of the significance of oxidative stress in the development of vascular tortuosity. Although further studies will be needed to elucidate the possible mechanisms by which oxidative stress enhances vascular tortuosity, our study also points toward possible prophylaxis and treatment for vascular tortuosity.


2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Nishant Kumar ◽  
Bettina Suhr ◽  
Stefan Marschnig ◽  
Peter Dietmaier ◽  
Christof Marte ◽  
...  

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


Author(s):  
Grimur Tomasson ◽  
Gisli Kristjan Olafsson ◽  
Hlynur Sigurporsson ◽  
Bjorn Por Jonsson ◽  
Kristjan Runarsson ◽  
...  

2021 ◽  
Vol 69 (10) ◽  
pp. 627-631
Author(s):  
Abigail R. Bland ◽  
John C. Ashton

Histochemistry of tumor sections is a widely employed technique utilized to examine cell death in preclinical xenograft animal models of cancer. However, this is under the assumption that tumors are homogeneous, leading to practices such as automatic cell counting across the entire section. We have noted that in our experiments the core of the tumor is largely or partially necrotic, and lacks evidence of vascularization (in contrast to the outer areas of the tumor). We note that this can bias and confound immunohistochemical analyses that do not take care to sample areas of interest in a way to take this into account. Design-based stereology with image analysis techniques is an alternative process that could be used to measure the volume of the necrotic region compared to the volume of the whole tumor.


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