Antibiotic resistance is a worldwide problem that is increasing largely due to the misuse of antibiotics in human health and agriculture. This situation is further exacerbated by a dearth of new antibiotic development, the focus of pharmaceutical companies having shifted to more lucrative treatments for chronic conditions such as elevated blood pressure. To conserve the efficacy of the current crop of antibiotics, it is vital that they are used appropriately by individuals. Effective education may be a means to achieve such appropriate use. This paper reports on a large-scale, mixed methods study, which employed a survey and oral questionnaires, undertaken with senior secondary Omani students. The study explored students’ understanding of antibiotic resistance as well as their attitudes to the issue of antibiotic resistance. The study findings indicated that, although some students had a reasonably clear understanding of antibiotic resistance, many had serious misconceptions that could result in misuse of antibiotics. The article concludes with suggestions for amending secondary school pedagogy in Oman to address the misconceptions. In August 2019, the chief medical adviser to the UK Government stated that antibiotic resistance endangers at least 10 million people every year and could kill us before climate change does .This article reports on a study that examined the understanding and attitudes towards antibiotic resistance amongst a cohort (n = 952) of senior secondary students in the Sultanate of Oman. It begins by providing an overview of antibiotic misuse and public understanding of antibiotic resistance before describing the methodology and findings from the Oman study. The article concludes with a discussion of the findings, particularly the misconceptions concerning antibiotics among students and how changes to the school curriculum might address such misconceptions.Less than a century ago, individuals were dying of bacterial infections and diseases that are treatable today. For example, pneumonia and tuberculosis killed approximately 300,000 Americans in 1930 and accounted for 22% of total deaths, but deaths from severe pneumonia infections declined by 60–75% when antibiotics were introduced in the late 1930s , with anSeveral studies have been conducted to clarify the extent of and reasons for the misuse of antibiotics. For example, in 2015, the World Health Organisation (WHO) conducted a large-scale, cross national 14-question survey about individuals’ knowledge about antibiotic resistance . The stuThe findings from the WHO and other studies beg the question of the extent to which members of the public understand the link between antibiotic misuse and the development of antibiotic-resistant bacteria. The findings of the WHO survey indicated that, in general, the participants were aware of the problem of antibiotic resistance but did not fully understand what caused it or what to do about it. A small study of public understanding of this issue in the US indicated that the link between misuse and resistance was recognized by most participants but only 30% felt that antibiotic resistance was a significant problem or that their personal actions might influence it . FurtherAlthough the WHO study did not include countries from the Middle East and Gulf Region, other studies indicate that misconceptions about and misuse of antibiotics is also prevalent in these regions. For example, in a study conducted in the north of Jordan where just over 40% of 1,060 randomly selected adults had taken oral antibiotics in the previous two months, 38% acquired the antibiotic without a prescription and 32% did not complete the recommended course of treatment . In addiA review of nine studies (from January 2000 to June 2017) undertaken in Gulf Cooperation Council countries found that there were many misconceptions concerning the efficacy of antibiotics, with nearly 40% of participants incorrectly believing that they were effective in treating minor ailments such as the common cold and coughs , and 44%The first author of this study is an Omani citizen, and all authors have an interest in and commitment to public understanding of science and education. Very few studies have been conducted on antibiotics use among the public in Oman. Two hospital-based studies conducted in Oman found that prescribing guidelines aimed at diminishing antibiotic resistance were not always followed ,27. The The three studies indicate that Oman likely shares similar issues in relation to antibiotic resistance as do other countries. The study reported in this paper aims to increase understanding of use of antibiotics in Oman with the objective of providing a basis for the introduction of health and education policy initiatives to improve public knowledge about antibiotics use. In addition, this study includes senior secondary students, thus extending an understanding of public knowledge and behaviours related to antibiotic use in the Gulf Countries  from theIn particular, this study aims to extend a version of the WHO survey to the Omani context and address the concern expressed in the review into antibiotic use in the Gulf Countries: “a multi-disciplinary approach must be put in place to educate the public on appropriate antibiotic use” . The cohThe Sultanate of Oman, in the south-east of the Arabian Peninsula, has a middle-income economy that is heavily dependent on dwindling oil reserves. The country’s political leadership has actively pursued a development plan that focuses on diversification, industrialization, and privatization, with the objective of generating more job opportunities and reducing the oil sector’s contribution to Oman’s Gross Domestic Product . Animal Oman’s population of approximately 4.6 million people is growing at approximately 3.1% per annum, with about half of the population being under 30 years of age. Education is free and compulsory until grade 10 (age 16) and remains free but non-compulsory until grade 12 (age 18). Secondary schools in Oman are segregated by gender.The school curriculum addresses the topic of antibiotics in grade 6, when students learn about Alexander Fleming and his discovery of penicillin, but misuse of and resistance to antibiotics is not covered. In the grade 11 Science and Environment Science Curriculum, there is some coverage of antibiotics, including issues of misuse and resistance . HoweverThis research was conducted with Omani Secondary level students aged 15–17 years old. It employed a mixed-methods methodology involving a quantitative survey (n = 952) followed by oral questionnaires (n = 107). The research was reviewed and approved by The Ministry of Education Technical Office for Studies and Development (project number 281978993), Department of School Counselling at the Ministry of Education (MoE) and the Department of School Health at the Ministry of Health (MoH). Consent, as consistent with Oman MoE approval, was implied, as no personal details were collected, the research is very low risk and the burden of participation minimal. Participants were informed about the nature and purpose of the research prior to their involvement.The survey and oral questionnaires explored the following research questions:What are students’ behaviours in relation to taking antibiotics? What are students’ understandings of antibiotics and antibiotic resistance and the factors that contribute to antibiotic resistance? What are students’ attitudes towards antibiotic use? The survey .The oral questionnaire comprised 5 questions aligned to the research questions  in urban and rural areas of all educational regions. The sample comprised 10 all-male and 10 all-female schools. The schools were selected to represent each of the eleven educational governors (directorates) in the Sultanate of Oman that offered grades 10–11. The school principals invited students in grades 10–11 to take part in the survey. A total of 1000 students were enrolled in the selected 20 schools and 952 students completed a paper-based survey giving a very high response rate of approximately 95%. Oral questionnaires were conducted with 107 students. The questionnaires were conducted in Arabic then translated into English by the research assistants. The translation was checked by two authors (AA and NR). The relevant part of the official Grade 11 Oman textbook was also translated into English and all authors read through the material to understand the content concerning antibiotics and the way in which it was presented.Statistical analysis of data was undertaken using the IBM SPSS Statistics for Windows Version 25 software package. Descriptive statistics were largely employed in the analysis to present certain findings graphically and, where appropriate, chi square tests were performed to compare frequencies between genders and rural/urban populations. The strength of association was also calculated using Cramer’s V test. For all tests, p-values of 0.05 or less were considered to be statistically significant. Interpretation criteria for Cramers’ V statistics are outlined in Data from the oral questionnaire was content analysed to capture and qualify the conceptions that students expressed in relation to (1) defining antibiotics and antibiotic resistance, (2) using antibiotics, and (3) attitudes towards antibiotics use. The researchers were particularly interested in identifying the most prevalent conceptions and misconceptions that students expressed about each of these three categories.A priori codes were used, and for each question, a specific set of codes was adopted. To establish inter-coder reliability, for each question, the two researchers coded 20 responses separately. They then cross-checked their coding, negotiated and refined and added to their codes as necessary. Afterwards, the two researchers independently coded 15 additional entries and used those results to calculate an inter-coder reliability score, which provided higher than 90% on every occasion. Once all questions were coded in this way, one of the researchers (NR) completed the coding of the remainder of the dataset.Two researchers (NR and FQ) developed a scheme for coding the responses to the oral questionnaire. Responses to survey questions are reported in this section with specific reference to each question of the survey  participants claimed to have taken antibiotics during the previous month before the survey (Survey Q1). This rose to 56% for the previous six months. Most students (65%) had obtained their antibiotics via a medical script obtained from a doctor (Survey Q2), while 17% of the cohort obtained antibiotics by other means (Survey Q2). Sixty percent of respondents received advice from health care providers on how to take their antibiotics in terms of dosage and duration (Survey Q3). This is broadly consistent with the proportion being prescribed antibiotics by their doctor, but only half (50%) of students claimed that their parents reinforced the prescription instructions (Survey Q4). Sixty-nine percent of students claimed that antibiotics were purchased from a pharmacy and only 6% mentioned that they took antibiotics left over from a previous prescription (Survey Q5).X2(2) = 6.244, p = .044, V = .081). Similarly, 52.9% of urban compared to 44.4% of rural participants indicated that they had received advice on dosage and timing from their parents (X2(2) = 6.506, p = .039, V = .083). This is suggestive of less available professional advice in rural areas, but the difference is only small.Some significant but small differences between urban and rural participants were evident relating to these results. A total of 63.1% of urban compared to 55% of rural participants indicated that they had received advice on dosage and timing by a doctor  offered an unclear or no reason to justify their decision, while the other half (53%) presented valid supportive reasons.These results relate to questions 6 to 8 and 16 of the survey, which explore participants’ understanding about the use of antibiotics and questions 1 and 3 of the oral questionnaire. Although 60% of students had received advice from health professions on dosage and duration (Survey Q3), only 38% of students correctly responded that they should complete the full course of antibiotics, while 48% believed they could stop the medication when they felt better and 14% did not know (Survey Q6). Sixty four percent of respondents identified as medically incorrect the following statement: “It is OK to use antibiotics that were prescribed to someone else as long as the disease that is being treated for is the same”, with only 20% believing this practice was appropriate (Survey Q7)).X2 (2) = 10.870, p = .004, V = .107). On the other hand, significantly fewer males (51.9%) than females (71.6%) identified as incorrect the statement: “It is OK to use antibiotics that were prescribed to someone else as long as the disease that is being treated for is the same”. This was a medium strength association (X2 (2) = 44.901, p < .001, V = .217).In relation to these questions, some small differences were apparent between genders. A small significant finding was that slightly fewer males (45.5%) than females (50.1%) indicated incorrectly that they should stop taking antibiotics when they felt better , almost equal numbers of respondents,  claimed “yes” or “I don’t know”, and about 20% responded “no” to the question of whether antibiotics are intensively used in the agricultural sector in Oman. None of the responses to the oral questionnaire featured concepts relevant to the use of antibiotics in agriculture.These results pertain to Questions 9–12 of the survey  as either correct or incorrect. The proportion of students accurately indicating whether these statements were correct or not is shown in As shown in X2 (1) = 10.384, p = .001, V = .104). In relation to gender differences, fewer males (56.9%) identified as incorrect the statement “antibiotics resistance is an issue in other countries but not in Oman” than females (69.1%) (X2 (1) = 14.974, p < .001, V = .125). Similarly, fewer males (55.6%) than females (65.8%) identified the statement: “It is possible to cure diseases related to viruses through using antibiotics” as incorrect (X2 (1) = 10.092, p = .001, V = .103). However, these gender differences are only small, and only evident for two of the 10 items.The Chi square tests of associations between urban/rural participants and gender and Omani students’ understanding of the concept of antibiotic resistance tapped by Survey Q13 detected three small significant associations. Significantly more urban (59.6%) than rural (48.9%) participants correctly identified the statement “if a bacterium is resistant to antibiotics, then the cure for the infection caused by the bacterium becomes extremely difficult or impossible” as correct (Students’ perceptions of ways to address antibiotic resistance (Survey Q14) are summarised in The most strongly endorsed items were that people should only use antibiotics on prescription by a doctor, wash hands constantly and ensure that their children are immunised on time. Hence the students appear to be focussing on the responsibility of individual antibiotic users to combat antibiotic resistance. The important roles of other people and organisations, such as pharmaceutical companies, doctors, the government and farmers, was less frequently recognised. Finally, the least frequently endorsed item about not keeping and reusing leftover antibiotics indicates that this is an area of potential traction in policy and educational messaging related to antibiotic resistance.The question of personal responsibility was further tapped by the second question of the oral questionnaire: “Would you take antibiotics without a prescription? Why/why not?” Only 15 of the 107 students claimed they would take antibiotics without a prescription, generally citing the need to do this in some kind of emergency, in some cases inaccurately again confusing antibiotics with analgesics; “Yes, because they inhibit pain in times of need”.In response to the third question in the oral questionnaire “Do you understand what is meant by antibiotic resistance? How does this develop?” the respondents’ ideas were expressed in relation to what resistance is, what causes it and what it results in. These results are summarised in Student responses to survey items related to attitudes towards antibiotic resistance and its impacts (Survey Q15) are summarised in Findings apparent in Congruent results were apparent from the oral questionnaire responses to question 4 . When asOne recurring misconception reflected in around a quarter of responses was the framing of resistance as a positive thing  felt that it was important to learn about antibiotic resistance in school (Survey Q17). Seventy percent of the 952 participants (N = 651) responded to the open item “Why do you think it’s important to learn about the use of antibiotics in schools?” with 29% of respondents mentioning raising awareness about the appropriate use of antibiotics for individuals and in society. So, there appeared, perhaps as a result of completing the survey, that the majority of students were aware that antibiotic misuse was a significant problem in Oman. A much smaller group (8%) responded in terms of disease prevention generally responding simply: “To prevent disease”. Surprisingly, given the number of responses, there appeared to be no misconceptions reported, although a small number of students (5) responded “I don’t know”. Finally, when asked in the oral questionnaire if they would like to know more about antibiotics and antibiotic resistance, the vast majority (86%) responded “Yes” but 18 responded “No”. Of the 18, 3 had stated that they would use antibiotics without a prescription.Some exploration of what students learnt at school about antibiotics was undertaken via an analysis of textbooks and a question in the oral questionnaire. Textbook analysis indicated that the only mention of antibiotic resistance appeared in the grade 12 Science and Environment textbook and comprised a short (just over 500 words in English) section titled “Problems with antibiotics” that also addressed side effects and allergies. A brief diagram and text explanation were provided indicating that bacteria can become resistant to antibiotics and multiply, rendering the antibiotic ineffective. This was followed by general advice about how to safely take medical drugs, including a brief sentence indicating that noncompliance with instructions leads to resistant diseases, but with no specific mention of the term antibiotics in that advice section. There were no discussion questions, activities, or references to the severity and importance of the growing concern about antibiotic resistance in this section of the textbook.Although there was clearly some attrition by this last question, Our findings suggest that there are knowledge gaps or misconceptions among a significant proportion of the student sample from Oman that could lead to the inadvertent misuse of antibiotics. This issue is of concern given the high level of antibiotic consumption identified in this study, possibly attributable to the easy availability of broad-spectrum antibiotics and lack of antimicrobial stewardship programs identified by Al-Malky et al . The vieThe findings of most concern, however, were those relating to the misuse of antibiotics including non-completion of courses and obtaining antibiotics from non-medical sources. Again, these have been reported elsewhere, including other territories in the Middle East and Gulf region ,25.Overall, the findings indicate a number of worrying gaps in knowledge which may influence behaviours in ways that could result in a failure to mitigate potential antibiotic resistance in Oman. However, they also offered a sense that individuals might treat antibiotics with care if these gaps were addressed.Clearly these findings indicate the need to educate the general public of Oman about the modes of action and use of antibiotics. Educational campaigns such as the GRACE (Genomics to combat Resistance to Antibiotics for Community acquired lower respiratory tract infection) open-access e-Learning curriculum have been developed around the world and are showing promise Click here for additional data file.S2 Appendix(DOCX)Click here for additional data file.


With the continuous development of urbanization and industrialization in the world, concrete is widely used in various engineering constructions as an engineering material. However, the consequent problem of durability of concrete structures is also becoming increasingly prominent. As an important additional measure, a protective coating can effectively improve the durability of concrete performance. Moreover, the uniformity of the concrete surface coating will directly affect its protective effect. Therefore, we propose a nondestructive inspection and evaluation method of coating uniformity based on infrared imaging and cluster analysis for concrete surface coating uniformity detection and evaluation. Based on the obtained infrared images, a series of processing and analysis of the images were carried out using MATLAB software to obtain the characteristics of the infrared images of the concrete surface. Finally, by extracting the temperature distribution data of the pixel points on the concrete surface, an evaluation method of concrete surface coating uniformity based on a combination of cluster analysis and hierarchical analysis was established. The evaluation results show that the determination results obtained by this method are consistent with the actual situation. This study has a positive contribution to the testing of concrete surface coating uniformity and its evaluation. Concrete structures are subjected to chloride ion attack, sulfate corrosion, and carbonation corrosion during service. These accelerate the deterioration of material properties and can lead to structural failure or even destruction in severe cases . In the Experts from different countries have carried out a lot of research for concrete corrosion protection. Concrete material ratios and microstructures have been optimized. These not only enhance the strength of concrete but also improve the anti-corrosion performance . HoweverHowever, the construction process of spraying protective coatings on the surface of concrete structures is prone to defects such as uneven thickness, porosity, and inclusions . These dAt present, there are few studies on the uniformity testing of spraying protective coatings on concrete surfaces. In the actual engineering application, this mainly relies on the visual inspection method. The method is a mostly subjective judgment by the naked eye of the inspector, which lacks a scientific basis and its accuracy is difficult to be guaranteed. In recent years, with the improvement of the accuracy of infrared imaging systems and the rapid development of image processing technology, infrared thermal imaging technology has gradually made significant breakthroughs in modern industry, medical and biological fields ,13,14. IIn general, the temperature resolution and contrast of the images obtained from thermal imaging cameras are generally low due to the limitations of their own performance. Moreover, the images also contain various noises, which bring a very negative impact on the detection and analysis of the target. Based on these problems, many researchers abroad have conducted in-depth studies on the correction of detector inhomogeneities, and the removal of periodic noise, etc. ,24,25,26In the process of infrared imaging inspection experiments, the thermal imaging camera collects the surface temperature distribution of each concrete specimen at different frames. For the massive amount of data, it is impossible to continue the analysis by the traditional manual analysis means. With the rapid development of modern computer operation speed and the in-depth research on data processing methods, it is possible to use the artificial intelligence method to confirm the results of experimental data prediction with those obtained from engineering experiments . ClusterTherefore, this study addresses the current problems of homogeneity testing of silane coatings. Infrared imaging non-destructive testing technology is used, combined with cluster analysis to statistically analyze the infrared imaging data, so as to achieve the evaluation of the homogeneity of silane coatings. The main research objectives include: (1) carry out experimental research on infrared imaging inspection of concrete surface coatings and obtain the temperature distribution images of concrete coating structure surfaces; (2) perform a series of processing of the acquired infrared images based on the MATLAB software and qualitatively determine the homogeneity of the concrete surface coating using morphological processing methods; (3) according to the large sample data of temperature distribution of each pixel point on the concrete surface at different moments, a new method based on a combination of cluster analysis and hierarchical analysis is proposed for determining the uniformity of concrete surface coating.When a protective coating is applied to the surface of a concrete specimen, the protective coating forms a coating structure on the surface. If the sprayed protective coating is uniform on the surface of the specimen, the changes in density, thermal conductivity, and specific heat capacity of each part of the coating structure should be the same. According to the basic theory of heat transfer, the distribution of temperature change characteristics caused by the coating on the surface is also consistent. If the protective coating on the surface of the specimen is not uniform, there will be variability in the distribution of the temperature change characteristics. Thus, the degree of uniformity of the protective coating on the surface of the concrete structure can be evaluated qualitatively based on these differences.An infrared imaging system is essentially a device that converts different electrical signals based on the temperature and emissivity of the natural scene. It generates a displayable infrared image by mapping the received infrared radiation energy of a target into grayscale values through an infrared detector. When the intensity of the infrared radiation of the target is higher, its grayscale value reflected in the infrared image is larger . The inf(1) Infrared radiation from the target, background, and various interferences is transmitted in the atmosphere and reaches the infrared optical system after a certain attenuation effect.(2) The optical system focuses the infrared radiation and then transmits the radiation to the infrared detector.(3) Infrared detectors convert the received infrared radiation into current signals of different strengths and weaknesses.(4) Transmission of the output electrical signal to an electrical signal processing system and enhancement by an amplifier therein.(5) The amplified electrical signal is transformed into a two-dimensional graphic that can be viewed directly on a computer after passing through an image processing system.14H32O3Si. Silane is a colorless liquid at room temperature, and its boiling point is 236 °C. The test used an infrared bulb as a thermal excitation source to apply continuous heat flow excitation to the concrete structure. In addition, an infrared imaging system was constructed with an SC7000 infrared camera from FLIR.The main component of this test silane coating is 2,4,4-trimethylpentyltriethoxysilane with molecular formula CConsidering the properties of the concrete specimen itself can affect the test results, the specimen was obtained by coring from the same subway tunnel pipe piece. The specimens were made into cylinders of 5 cm in diameter and 10 cm in height. Three groups of tests were designed according to the different degrees of uniformity of the sprayed silane. They were classified as more uniform (N1), non-uniform (N2), and very non-uniform (N3). The infrared detection test system is shown in (1) Placement of the thermal imaging cameraUse the triangle bracket to place the thermal imaging camera in a suitable position. The infrared thermal imager is adjusted to the horizontal center position so that the lens of the thermal imager and the test piece are at the same horizontal height.(2) Placement of concrete specimens1 and place it in the uniform temperature field formed by the two infrared bulbs to ensure the uniform heating of the specimen surface. The distance between the lens of the thermal imager and the test piece is about 1 m.Use the bracket to fix the two infrared bulbs and adjust the corresponding position. Take a concrete specimen A(3) Connect infrared equipment and set parametersConnect the computer interface to the GigE vision port of the infrared camera with an Ethernet cable, and connect the data collected by the camera to the infrared image processing software through the CNUC management tool in the computer.(4) Preheat the infrared bulb and cameraAfter connecting the power supply, turn on the switch of the infrared bulb and the power supply of the camera for preheating for about 5 min.(5) Acquisition of infrared imagesAdjust the focal length of the infrared camera lens until the concrete specimen appears clearly and steadily in the computer, then start the infrared image acquisition. In order to observe the obvious temperature changes on the surface of the concrete, this experiment is a total of 800 s of an infrared image video stream.(6) Save and record the image dataSave the data in the form of video captured by the infrared camera to a designated location for subsequent image and data processing.(7) Turn off the heat sourceTurn off the infrared bulb switch and stop heating so that the temperature of the concrete specimen drops to the initial temperature.(8) Concrete surface silane spraying1 surface temperature drops to the initial temperature, the concrete surface is sprayed with silane. The concrete specimen after spraying silane is recorded as A2.When the above-mentioned concrete specimen A2 and specimen A1 are tested under the same experimental environment. Repeat the above steps (1) to (7) to collect the infrared thermal image data of the concrete specimen A2 sprayed with silane and save it.After the surface of the concrete specimen is completely infiltrated with silane, the environmental conditions during the experiment are controlled so that specimen AInfrared images characterize the infrared radiation distribution of an object. The overall grayscale distribution of the image is low, and the image is prone to grayscale concentration. In addition, during the actual imaging process, noise sources from the external environment may lead to multiple noises in the infrared image, which affects the information of the infrared image itself. Therefore, a series of image processing is needed for the IR images.Before image analysis, pre-processing operations need to be performed according to its features to enhance the contrast of the image. This facilitates the extraction of image features in the subsequent processing and improves the accuracy of the determination results. The pre-processing process generally includes image quality evaluation, image noise removal, image sharpening, etc. ,39,40.Commonly used objective evaluation metrics include entropy, standard deviation, etc. Among them, entropy reflects the information contained in the image . The higThe noise of the image signal can be regarded as an interference signal, which has a random nature. Statistical features are commonly used to describe the noise, such as distribution functions and probability density functions of mean, variance, correlation functions, etc. In this study, the median filtering method is used to remove it . The medf, the gradient at  is defined asIn order to extract the features of the concrete surface area, enhance the contour shape of the image, and make the edge information of the concrete image more prominent, the image sharpening method is used for the corresponding processing. The gradient method is often used in MATLAB to achieve image sharpening . For an By pre-processing the infrared image, the concrete image edge information is clearer and the surface area detail features are more obvious. A good foundation was laid for the subsequent edge detection processing.In image processing, the region of interest in an image is generally referred to as the target (ROI), while the rest of the image is referred to as the background. Based on this principle, edge detection and segmentation of image targets can be achieved. In infrared images, the grayscale value of pixels at the target edge changes significantly, creating a discontinuity. For edges with step changes, the first-order derivative can be used to detect whether a point in the image is an edge point. The second-order derivative can be used to determine whether a pixel point lies to the left or right of an edge.In image processing, edge detection can be accomplished by convolution with differential operators ,45. Diffg denotes the pixel value of the input image; f denotes the pixel value of the output image; and T represents the threshold.At present, a large number of analytical and computational methods have been formed for image segmentation, such as segmentation techniques by setting thresholds, segmentation based on genetic algorithms, etc. Among them, the image segmentation based on the threshold method has the advantages of large applicability, high operational efficiency, and speed . The calg = 0, the background pixel of the image g = 1. When the threshold value is determined, the grayscale value of each pixel point in the image is compared with the threshold value. In turn, two different regions of the image segmentation can be obtained.When for the target pixel of the image T = 0.5373 was obtained. After determining the threshold size, the image segmented by the iterative thresholding method was obtained based on MATLAB.An iterative algorithm is used for the calculation of the threshold values. The maximum gray value and the minimum gray value of the image were obtained based on the gray statistics of the concrete infrared image. In addition, the threshold value There are incomplete edges and voids in regions present in the threshold-segmented infrared images of concrete. The binary image is processed by the morphological method. The processing operation of binary images can be realized by using the mathematical morphology method. Based on the closed operation in image morphology processing, MATLAB is applied to connect the broken edges and fill the holes, etc. . The mork initial centroids randomly as clustering centers in a determined object containing n samples. The Euclidean distance is used to calculate the distance between other samples and the cluster center, and the sample points are grouped into the class with the closest distance to the cluster center. Then, the mean value of each class is used as the new clustering center, and the samples are re-classified into k classes [k value is the number of classes, which is determined by the sum of the squared errors (SSE) [i-th cluster, p is any sample point in SSE is the sum of squared clustering errors for all samples. The degree of merit of the cluster analysis results can be measured, and thus the appropriate k value can be determined.Combining the principles of algorithm selection and the characteristics of each algorithm, this study adopts the k-means algorithm for clustering analysis of pixel point temperature data. The k-means algorithm firstly selects  classes ,49. Thusrs (SSE) .(3)SSE=In order to determine the loss of misclassified concrete surface pixel points, the posterior probability that a pixel point belongs to some overall, i.e., the affiliation degree, is obtained. The Bayes discriminant method is used for discriminant analysis of the classification of each pixel point on the concrete surface . The bask p-dimensional overall j = 1, 2, 3, …, k. Note that the posterior probability function of the sample x judged to belong to i overall. A series of mathematical transformations of the above function yields the Bayes discriminant function as:Suppose to Gi is :(4)P(k|Xx belongs to k is the largest when the maximum x is determined to belong to the kth overall.The posterior probability that sample In order to reduce the influence of the concrete specimen’s own characteristics on the experimental results, the temperature pixel points of the specimen surface before and after spraying silane were clustered and discriminated separately. It is assumed that the clustering values of all pixel points on the concrete surface before spraying silane are set Q, and after spraying silane are set D. The absolute value of the difference between the two is set Z = |Q − D|. If the concrete surface is uniformly coated with silane, the clustering results of the same pixel on the concrete surface before and after the spraying of silane should be the same, i.e., Z = 0. Therefore, the uniformity of silane spraying on the concrete surface can be judged qualitatively by counting the difference in the clustering results of each pixel.U denotes the unevenness of the concrete surface coating; in is the total number of pixel points at Z = i; ω1, ω2, …, iω are the corresponding weight values; jth pixel point; M denotes the total number of pixel points on the concrete surface.Due to the different affiliation of each pixel point obtained from Bayes discriminant calculation, the clustering difference values of each pixel point on the concrete surface before and after spraying the coating are also different. In order to calculate the coating uniformity more accurately, the weight value analysis ,54. ThenU. The specific division grades are shown in In order to describe the uniformity grade situation of the concrete surface coating, the concrete surface coating uniformity grade can be divided into four grades according to the calculated inhomogeneity A total of 800 s of infrared image video streams were acquired for each experiment. Then, the IR image processing software ALTAIR was used to export the IR thermal images of the temperature distribution on the surface of the test block. The results of the initial state t = 0 and the final state t = 800 s of the experimental group N1 are shown in In order to facilitate the observation and comparison of the silane on the concrete surface temperature change pattern during the heating process, the graph of the average temperature of the concrete surface with the number of frames is drawn, as shown in By comparing the surface average temperature change law of concrete before and after spraying silane. It can be seen that the average temperature rise rate of concrete structure is accelerated after spraying silane protective coating. This indicates that when silane coating forms a coating structure on the concrete surface, it affects the thermodynamic parameters such as specific heat capacity and thermal conductivity of the concrete structure itself. In addition, when the amount of sprayed silane varies, the degree of its influence will also vary.To facilitate the extraction of features from concrete infrared images, different regions of the images need to be labeled. This facilitates the extraction and calculation of the image features. Since the obtained concrete images are binarized, the threshold value can be set to 0. In order to obtain the effect of the labeling process, the labels are highlighted in MATLAB in different colors to form a pseudo-color image. The image after processing is shown in The area S of each area in the image is used as the basic feature of the infrared image. It is also used as an analytical index to determine the degree of uniformity of the concrete surface coating. In the above 1y, 2y, 3y, and 4y, respectively, as the indicator variables for each sample point. The final results of the pixel point temperature data statistics are obtained and shown in Taking the experimental group N1 as an example, the infrared images of concrete with uncoated silane on the surface are intercepted. The temperature data at different moments corresponding to the corresponding area are derived separately. The region includes a total of 17,098 pixel points. The temperature values corresponding to the moments of the 5000th, 10,000th, 15,000th, and 20,000th frames are denoted by k-values are taken as 2, 3, 4, 5, 6, 7, 8, 9, and 10 in order. Moreover, the distance of each pixel point to the cluster center in the cluster it belongs to is calculated by applying the SPSS Statistics 19 software. Then, the summation was obtained to obtain the magnitude of the error sum of squares corresponding to each different value of k, and the related line graphs were drawn, as shown in The clustering analysis for the pixel point temperature data was implemented using the k-means algorithm. The k increases, the finer the temperature samples are divided. Therefore, the cohesiveness of the data in each cluster will gradually increase, and the error squared and SSE will naturally become smaller. k = 5 is the optimal value for the cluster analysis of pixel point temperature data.From the above k-values in the algorithm were determined, iterative and classification calculations were performed on the uncoated silane concrete surface temperature data. The four indicator temperature values of the final clustering center and the clustering results of each pixel point are obtained and shown in Once the The clustering results show that each pixel point on the concrete surface is clustered into five categories according to the distribution of temperature. Categories I~V indicate the temperature in order from high to low. It can be understood that the concrete surface forms a high-temperature zone, a higher temperature zone, a medium temperature zone, a lower temperature zone, and a low-temperature zone. The number of pixel points in each of these classes is valid. The total number of pixel points in each class was counted, and the results are shown in We can see from T for a given pixel point is obtained as follows:Based on the clustering analysis results obtained earlier, Bayes discriminant analysis is calculated assuming that the prior probabilities of the points of each overall sample are equal. The formula for calculating the value of the function y1, y2, y3, and y4 values of the unknown pixel points are brought into the above equation. The values of T1, T2, T3, T4, and T5 were calculated. Moreover, we compared the magnitude of these five values and took the category corresponding to the maximum value as the Bayesian discriminant result of the pixel point. The values were brought into the posterior probability calculation formula to obtain the posterior probability of each pixel point being discriminated into each category. To determine the cluster affiliation of any pixel point on the concrete surface, the maximum posterior probability value of the pixel point was taken as the affiliation of the pixel point belonging to the corresponding category. The In The clustering results and the affiliation degree of each pixel point on the concrete surface before and after the coating were calculated for the specimens of the above experimental group N1. The results are shown in U = 0.122. The uniformity of the concrete surface coating in this group is evaluated as more uniform. Then, the inhomogeneity of the surface coating of concrete specimens in experimental group N2 and experimental group N3 are calculated, respectively. The results of their evaluation are obtained and shown in The distribution of the variable Z is obtained from the results of the pixel point clustering statistics. The distribution characteristics roughly reflect the uniformity of the surface silane spraying to some extent. The total number of pixels is 6147, 3440, 2179, and 1345 when Z = 1, 2, 3, and 4. Finally, the unevenness of the surface coating of concrete specimens in experimental group N1 can be calculated as It can be seen from This study conducted research on concrete surface coating uniformity detection and its determination and evaluation method. A nondestructive inspection and evaluation method of coating uniformity based on infrared imaging is proposed. We analyzed the images obtained from the non-destructive testing of infrared imaging by using MATLAB software. The characteristics of the infrared images of the concrete surface were obtained, and a method for determining the uniformity of the concrete surface coating by infrared images was proposed. We extracted the temperature distribution data of concrete surface pixel points and established a new evaluation method of concrete surface coating uniformity based on a combination of cluster analysis and hierarchical analysis. The results show that the determination results obtained by the method are consistent with the actual situation.We compared the two methods based on MATLAB infrared image analysis processing and based on cluster analysis to determine the uniformity of the concrete surface coating. The results obtained from the image-processing-based method are more influenced by environmental factors. The method requires that the concrete structure itself is homogeneous, and also ensures that the concrete surface is heated completely uniformly. Therefore, the accuracy of the determination results obtained by this method is low. For the proposed new method of evaluating the uniformity of surface coating based on cluster analysis, the advantage of this method is that it can eliminate the influence of the characteristics of the concrete specimen itself on the evaluation results. The accuracy of the determination results is also higher.At present, the application of infrared imaging non-destructive testing technology to detect the uniformity of concrete surface coatings is still in the preliminary stage. The factors affecting the infrared inspection results are many and complex. Coating uniformity testing experiments and processing methods for infrared images are not mature. Therefore, more in-depth research is needed to detect the uniformity of concrete surface coating more scientifically, accurately, and quickly. The proposed evaluation method is based on a large sample of temperature data of concrete surface pixel points. When the number of samples is small, the evaluation results obtained by the method may have some errors. Therefore, a more in-depth study of the uniformity evaluation method can be conducted when the number of samples is small. In addition, the evaluation results obtained are a qualitative uniformity rating rather than a quantitatively accurate description of the results. The quantitative study for the uniformity of concrete coatings also needs to be further investigated.In this study, the uniformity of concrete surface coating is taken as the research object. We obtained the infrared thermal images of the concrete surface by the experiment of infrared imaging inspection of the concrete structure. The results obtained from the experiments are processed by applying the statistical methods of MATLAB image processing and cluster analysis, respectively. Finally, we derived a method for determining the uniformity of the concrete surface coating. The main conclusions are as follows:1. A new non-destructive testing method applicable to concrete surface coating uniformity detection is proposed, infrared imaging nondestructive testing technology.2. The infrared images acquired in the experiment were analyzed and processed based on MATLAB software. We derived the final features of the concrete surface images.3. A new method based on the combination of cluster analysis and hierarchical analysis is proposed to evaluate the study of the uniformity of concrete surface coating. The results show that the evaluation results obtained from the calculation are more consistent with the actual spraying situation.In future research, the quantitative evaluation of concrete surface coating uniformity and the evaluation of temperature data for small samples of pixel points can be further investigated.


This paper investigated the influence of recycled ceramics and grazed hollow beads on the mechanical, thermal conductivity and material properties of concrete. The results showed that the concentration of recycled ceramics and grazed hollow beads has significant optimization on the workability and thermal properties of the concrete. However, the superabundant concentration can reduce the hydration degree of the concrete, which results in the suppressed production of C-S-H gel and the increase of material defects. In summary, considering the coordinated development of key factors such as thermal insulation properties, mechanical properties and microstructure, 10% RCE and 60% GHB are the optimal material system design methods. Environmental pollution and resource and energy shortages have become the main problems hindering the development of industrialization and urban construction ,2,3,4,5.Based on the characteristics that the mechanical properties of recycled ceramic coarse aggregate concrete are lower than ordinary concrete, recycled ceramic concrete is more widely used in the preparation of enclosure structures. The engineering application of the envelope structure with heat preservation and heat insulation properties can effectively alleviate the problem of energy shortage in China which conforms to the fundamental national policy of energy saving and emission reduction ,28,29,30The goal of this study is to fill these research gaps by investigating the mechanical properties, thermal conductivity and material characteristics of recycled thermal insulation concrete (RTIC) that incorporates grazed hollow beads and recycled ceramics as replacement fine and coarse aggregates. Slump, density, splitting strength, compressive strength, axial compressive strength, elastic modulus and thermal conductivity were measured to evaluate the impact of grazed hollow beads and recycled ceramics on the macroperformance. Material morphology, hydration products and functional groups were investigated to determine the mesoscopic properties of recycled thermal insulation concrete. In summary, based on the above research results, new ideas are provided for the actual use of lightweight thermal insulation cement-based materials in civil engineering, such as the construction of thermal insulation structural floor slabs and the preparation of special concrete structures.w/c) was 0.5 and the mixing proportions of the concrete mixtures are listed in Ordinary Portland Cement (P.O. 42.5 N), local nature sand (NSD), grazed hollow beads (GHB), recycled ceramics (RCE) and nature stone (NSE) were used throughout the experiment. The mechanical properties of cement and chemical composition of cement are shown in The recycled thermal insulation concrete (RTIC) specimens had dimensions of 150 mm × 150 mm × 150 mm (144 pieces) and 300 mm × 300 mm × 30 mm (72 pieces) according to the Chinese standard GB/T 50081-2002  and GB/TThe workability of recycled thermal insulation concrete based on the coupling influence between GHB and RCE was determined and conducted through the slump and density test according to Chinese standard GB/T50080-2016  and GB/TA total of 144 RTIC specimens (150 mm × 150 mm × 150 mm) were prepared for series experiments of compressive strength (72 pieces) and splitting strength (72 pieces) according to Chinese standard GB/T50081-2002 .The thermal insulation property of concrete is usually reflected by thermal conductivity. In this paper, a total of 72 specimens (300 mm × 300 mm × 30 mm) were prepared to determine the thermal conductivity of concrete specimens based on the steady-state and double-plate method shown in .To further explore the effect of RCE and GHB on the mechanical properties and thermal conductivity early performance of recycled thermal insulation concrete, several macro-experimental methods were conducted. A total of 80 experimental samples were subjected to scanning electron microscopy  , X-ray diffraction  , and Fourier-transform infrared spectroscopy   to analyze the changes in the micromorphology, hydration products, and chemical bonding or molecules. The preparation and drying conditions of these samples were following Chinese standard GB/T 16594-2008 , GB/T 30In this section, the macroscopic comprehensive performance of RTIC is studied. This section mainly explores the influence of GHB and RCE on the working performance, lightweight performance, mechanical properties and thermal conductivity of RTIC under the coupling effects of different doping amounts.The experimental results and changes of slump subjected to the coupling influence between GHB and RCE on fresh concrete are shown in The experimental results and changes of compressive strength are shown in The experimental results and changes of thermal conductivity and insulation property values of RTIC subject to the coupling influence between GHB and RCE are shown in In order to further explore the modification mechanism of RTIC on the comprehensive properties of concrete, a set of meso-experimental methods to explore the coupled effects of GHB and RCE on RTIC’s microstructure, material morphology and key hydration products are discussed in this section.The analysis of the material morphology of RTIC is shown in 3. The increase of CaCO3 leads to premature calcification or aging of concrete, which is very unfavorable to the development of mechanical properties. (3) Further analysis found that GHB had a promoting effect on the formation of Tobermorite. With the increase of GHB, the characteristic peak intensity and crystal yield of Tobermorite increased. Tobermorite is a kind of hydrated calcium silicate with high crystallinity. It has strong thermal insulation performance and can improve the thermal insulation performance of concrete. Therefore, with the increase of GHB, the thermal insulation performance of concrete is also enhanced.The experimental results of the crystal composition and hydration products of RTIC are shown in 3 production in concrete.The effect of RCE and GHB on the functional groups of concrete hydration products is shown in K is the quantitative characterization of the coupled effects of RCE and GHB content on concrete comprehensive characteristics.The effects of RCE and GHB on RTIC workability, compressive strength, splitting tensile strength and insulation properties can be quantitatively determined by the correlation principle. The interaction between these two parameters is determined as follows:The calculation results of the influence coefficient of RCE and GHB on concrete performance are shown in RCE can inhibit the density and mechanical properties of RTIC, but it has little effect on the working and thermal insulation properties of RTIC. GHB can improve the workability and insulation properties of RTIC (155.6 and 91.9% maximum increase), but decreases the density and mechanical properties (9.9 and 33.9% maximum decrease).3, which was detrimental to the macroscopic mechanical properties of RTIC. Meanwhile, the increase in GHB led to an increase in the production of Tobermorite, which largely improves the insulation properties of RTIC.The incorporation of GHB and RCE inhibited the formation of CH and C-S-H and promoted the increase of CaCOGHB and RCE can be used to prepare regenerated thermal insulation concrete due to the synergistic development of mechanical properties and thermal insulation properties. It is considered that 10% RCE and 60% GHB are the best doping amounts. The new thermal insulation concrete material prepared based on this material design system can be used in practical projects such as prefabricated roof structures in civil engineering, special transportation pipelines, and link bridges in equipment and accessory buildings.GHB and RCE can be used to prepare regenerated thermal insulation concrete due to the synergistic development of mechanical properties and thermal insulation properties. It is considered that 10% RCE and 60% GHB are the best doping amounts.This paper investigated the influence of RCE and GHB on the mechanical, thermal conductivity and material properties of concrete, and the following conclusions can be drawn: