Microcrack Study of Cement-Based Materials by Means of Image Analysis

1994 ◽  
Vol 370 ◽  
Author(s):  
Yahia Alhassani ◽  
Alain Bascoul ◽  
Erick Ringot

AbstractThe relationship between microscopical damaging of concrete and its mechanical parameters such as Young's modulus and degree of reversibility is a basic issue. In the same time, transport properties and of course the durability of civil engineering and hydraulic structures are linked to the state of microcracking.The replica technique has been developed in our laboratory in order to study microcracks with a scanning electron microscope. This non-destructive method allows observation of the imprint of the concrete surface and to follow the evolution of the alterations with time. An objective quantitative analysis requires numerous replicas and many microscopic fields within each replica.After a brief state of the art of the automatic method of extraction of lines by image processing, we propose a specific algorithm of image analysis which allows the cleaning of the pictures and the extraction of the microcrack skeleton. Today, this procedure has been validated on cement paste samples. It has to be improved to be applied on concrete.The measured parameters are the microcrack specific lengths and their orientation. The objective values measured by means of this procedure compare favorably to results obtained by hand drawing.

2020 ◽  
Vol 9 (1) ◽  
pp. 303-322 ◽  
Author(s):  
Zhifang Zhao ◽  
Tianqi Qi ◽  
Wei Zhou ◽  
David Hui ◽  
Cong Xiao ◽  
...  

AbstractThe behavior of cement-based materials is manipulated by chemical and physical processes at the nanolevel. Therefore, the application of nanomaterials in civil engineering to develop nano-modified cement-based materials is a promising research. In recent decades, a large number of researchers have tried to improve the properties of cement-based materials by employing various nanomaterials and to characterize the mechanism of nano-strengthening. In this study, the state of the art progress of nano-modified cement-based materials is systematically reviewed and summarized. First, this study reviews the basic properties and dispersion methods of nanomaterials commonly used in cement-based materials, including carbon nanotubes, carbon nanofibers, graphene, graphene oxide, nano-silica, nano-calcium carbonate, nano-calcium silicate hydrate, etc. Then the research progress on nano-engineered cementitious composites is reviewed from the view of accelerating cement hydration, reinforcing mechanical properties, and improving durability. In addition, the market and applications of nanomaterials for cement-based materials are briefly discussed, and the cost is creatively summarized through market survey. Finally, this study also summarizes the existing problems in current research and provides future perspectives accordingly.


Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4397
Author(s):  
Kazuya Kikunaga

A mixture of positive and negative static charges exists in the same plane on an insulator surface, and this can cause production quality problems at manufacturing sites. This study developed a system with a vibration array sensor to rapidly measure the surface potential distribution of an object in a non-contact and non-destructive manner and with a high spatial resolution of 1 mm. The measurement accuracy differed greatly depending on the scanning speed of the array sensor, and an optimum scanning speed of 10 mm/s enabled rapid measurements (within <3 s) of the surface potential distribution of a charged insulator (area of 30 mm × 30 mm) with an accuracy of 15%. The relationship between charge and dust on the surface was clarified to easily visualize the uneven static charges present on it and thereby eliminate static electricity.


2012 ◽  
Vol 39 (11) ◽  
pp. 813 ◽  
Author(s):  
Roland Pieruschka ◽  
Hendrik Poorter

No matter how fascinating the discoveries in the field of molecular biology are, in the end it is the phenotype that matters. In this paper we pay attention to various aspects of plant phenotyping. The challenges to unravel the relationship between genotype and phenotype are discussed, as well as the case where ‘plants do not have a phenotype’. More emphasis has to be placed on automation to match the increased output in the molecular sciences with analysis of relevant traits under laboratory, greenhouse and field conditions. Currently, non-destructive measurements with cameras are becoming widely used to assess plant structural properties, but a wider range of non-invasive approaches and evaluation tools has to be developed to combine physiologically meaningful data with structural information of plants. Another field requiring major progress is the handling and processing of data. A better e-infrastructure will enable easier establishment of links between phenotypic traits and genetic data. In the final part of this paper we briefly introduce the range of contributions that form the core of a special issue of this journal on plant phenotyping.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1543
Author(s):  
Francisca Guadalupe Cabrera-Covarrubias ◽  
José Manuel Gómez-Soberón ◽  
Carlos Antonio Rosas-Casarez ◽  
Jorge Luis Almaral-Sánchez ◽  
Jesús Manuel Bernal-Camacho

The porosity of mortars with recycled ceramic aggregates (10, 20, 30, 50, and 100% as a replacement of natural aggregate) was evaluated and analyzed using three different techniques. The results of gas adsorption (N2), Scanning Electron Microscopy (SEM) image analysis and open porosity allowed establishing the relationship between the recycled aggregate content and the porosity of these mortars, as well as the relationship between porosity and the physical and mechanical properties of the mortars: absorption, density, compressive strength, modulus of elasticity, and drying shrinkage. Using the R2 coefficient and the equation typology as criteria, additional data such as Brunauer, Emmett, and Teller (BET) surface area (N2 adsorption) established significant correlations with the mentioned properties; with SEM image analysis, no explanatory relationships could be established; and with open porosity, revealing relationships were established (R2 > 0.9). With the three techniques, it was confirmed that the increase in porosity is related to the increase in the amount of ceramic aggregate; in particular with gas adsorption (N2) and open porosity. It was concluded that the open porosity technique can explain the behavior of these recycled mortars with more reliable data, in a simple and direct way, linked to its establishment with a more representative sample of the mortar matrix.


2021 ◽  
Vol 7 (2) ◽  
pp. 19
Author(s):  
Tirivangani Magadza ◽  
Serestina Viriri

Quantitative analysis of the brain tumors provides valuable information for understanding the tumor characteristics and treatment planning better. The accurate segmentation of lesions requires more than one image modalities with varying contrasts. As a result, manual segmentation, which is arguably the most accurate segmentation method, would be impractical for more extensive studies. Deep learning has recently emerged as a solution for quantitative analysis due to its record-shattering performance. However, medical image analysis has its unique challenges. This paper presents a review of state-of-the-art deep learning methods for brain tumor segmentation, clearly highlighting their building blocks and various strategies. We end with a critical discussion of open challenges in medical image analysis.


2021 ◽  
Vol IV (2) ◽  
pp. 84-97
Author(s):  
Alina Popa ◽  

With the recent COVID-19 pandemic, the world we knew changed significantly. The buying behavior shifted as well and is reflected by a growing transition to online interaction, higher media consumption and massive turn to online shopping. Companies that aim to remain top of mind to customers should ensure that their way of interacting with user is both relevant and highly adaptive. Companies should invest in state-of-the-art technologies that help manage and optimize the relationship with the client based on both online and offline data. One of the most popular applications that companies use to develop the client relationship is a Recommender System. The vast majority of traditional recommender systems consider the recommendation as a static procedure and focus either on a specific type of recommendation or on some limited data. In this paper, it is proposed a novel Reinforcement Learning-based recommender system that has an integrative view over data and recommendation landscape, as well as it is highly adaptive to changes in customer behavior, the Holistic Adaptive Recommender System (HARS). From system design to detailed activities, it was attempted to present a comprehensive way of designing and developing a HARS system for an e-commerce company use-case as well as giving a suite of metrics that could be used for its evaluation.


2021 ◽  
Vol 36 (5) ◽  
pp. 596-607
Author(s):  
O. Ekşi

Abstract The aim of this study is to determine the thickness distribution of a food package using a non-destructive method. Initially, thickness measurements were carried out using an experimental procedure for thermoformed samples that were used for food packaging. Additionally, in this study, image analysis was used for the first time to determine the thickness distribution of the thermoformed products non-destructively. Image analysis software was employed for the estimation of thickness distribution. Measured thickness results were compared to those estimated using image analysis. Based on the results of the current study, image analysis may be an alternative method for non-destructive testing of thermoformed food packages even in a mass production line. Image analysis can be used to determine not only thickness distribution but also the weakest regions in a food package.


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