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Currently, renewable energies, including wind energy, have been experiencing significant growth. Wind energy is transformed into electric energy through the use of wind turbines (WTs), which are located outdoors, making them susceptible to harsh weather conditions. These conditions can cause different types of damage to WTs, degrading their lifetime and efficiency, and, consequently, raising their operating costs. Therefore, condition monitoring and the detection of early damages are crucial. One of the failures that can occur in WTs is the occurrence of cracks in their blades. These cracks can lead to the further deterioration of the blade if they are not detected in time, resulting in increased repair costs. To effectively schedule maintenance, it is necessary not only to detect the presence of a crack, but also to assess its level of severity. This work studies the vibration signals caused by cracks in a WT blade, for which four conditions (healthy, light, intermediate, and severe cracks) are analyzed under three wind velocities. In general, as the proposed method is based on machine learning, the vibration signal analysis consists of three stages. Firstly, for feature extraction, statistical and harmonic indices are obtained; then, the one-way analysis of variance (ANOVA) is used for the feature selection stage; and, finally, the k-nearest neighbors algorithm is used for automatic classification. Neural networks, decision trees, and support vector machines are also used for comparison purposes. Promising results are obtained with an accuracy higher than 99.5%.

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The seismo-electromagnetic theory describes the growth of fractally distributed cracks within the lithosphere that generate the emission of magnetic anomalies prior to large earthquakes. One of the main physical properties of this theory is their consistency regarding the second law of thermodynamics. That is, the crack generation of the lithosphere corresponds to the manifestation of an irreversible process evolving from one steady state to another. Nevertheless, there is still not a proper thermodynamic description of lithospheric crack generation. That is why this work presents the derivation of the entropy changes generated by the lithospheric cracking. It is found that the growth of the fractal cracks increases the entropy prior impending earthquakes. As fractality is observed across different topics, our results are generalized by using the Onsager's coefficient for any system characterized by fractal volumes. It is found that the growth of fractality in nature corresponds to an irreversible process.

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The detection of cracks is an important monitoring task in civil engineering infrastructure devoted to ensuring durability, structural safety, and integrity. It has been traditionally performed by visual inspection, and the measurement of crack width has been manually obtained with a crack-width comparator gauge (CWCG). Unfortunately, this technique is time-consuming, suffers from subjective judgement, and is error-prone due to the difficulty of ensuring a correct spatial measurement as the CWCG may not be correctly positioned in accordance with the crack orientation. Although algorithms for automatic crack detection have been developed, most of them have specifically focused on solving the segmentation problem through Deep Learning techniques failing to address the underlying problem: crack width evaluation, which is critical for the assessment of civil structures. This paper proposes a novel automated method for surface cracking width measurement based on digital image processing techniques. Our proposal consists of three stages: anisotropic smoothing, segmentation, and stabilized central points by k-means adjustment and allows the characterization of both crack width and curvature-related orientation. The method is validated by assessing the surface cracking of fiber-reinforced earthen construction materials. The preliminary results show that the proposal is robust, efficient, and highly accurate at estimating crack width in digital images. The method effectively discards false cracks and detects real ones as small as 0.15 mm width regardless of the lighting conditions.

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OBJECTIVES: This study investigated the incidence of root dentin defects after the use of different post space preparation (PSP) drills. MATERIALS AND METHODS: Seventy-two bovine incisors were selected and obtained 14-mm-long root sections. Twelve roots served as controls with no intervention (G1). The 60 root canals remaining were instrumented using the crown-down technique with the ProTaper Next system and obturated using the lateral condensation technique. Specimens were randomly distributed into 5 groups (n = 12) according to the operative steps performed: G2, root canal instrumentation and filling (I+F); G3, I+F and PSP with Gates-Glidden drills; G4, I+F and PSP with Largo-Peeso reamers; G5, I+F and PSP with Exacto drill; and G6, I+F and PSP with WhitePost drill. Roots were sectioned at 3, 6, 9, and 12 mm from the apex, and digital images were captured. The presence of root dentin defects was recorded. Data were analyzed by the χ2 test, with p < 0.05 considered to indicate statistical significance. RESULTS: Root dentin defects were observed in 39.6% of the root sections. No defects were observed in G1. G5 had significantly more cracks and craze lines than G1, G2, and G3 (p < 0.05), and more fractures than G1, G2, G3, and G4 (p < 0.05). When all root sections were analyzed together, significantly more defects were observed at the 12-mm level than at the 3-mm level (p < 0.05). CONCLUSIONS: PSP drills caused defects in the root dentin. Gates-Glidden drills caused fewer root defects than Largo-Peeso reamers and Exacto drills.

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Reinforced concrete structures are prone to cracking. The development of cementitious matrices with the capacity for self-healing soon after these cracks appear represents savings with inspections and repairs of the structures. Self-healing can be stimulated with the use of crystalline admixtures. Such materials easily react with water and increase the density of C-S-H (hydrated-calcium-silicate), forming insoluble deposits blocking existing pores and cracks. In this research, self-healing in concrete cracks was evaluated using three different crystalline admixtures, submitted to two and six wetting-drying cycles. The efficiency of self-healing was evaluated by optical microscopy and using the chloride diffusion test, which allowed calculating the predicted useful life of the concretes. The results highlight two important findings: (i) in optical microscopy, crystalline admixtures were not efficient in promoting self-healing on the surface of cracks in any of the studied concretes; (ii) the passage of chlorides by diffusion was lower for concretes with crystalline admixtures compared to the reference, showing better internal healing of these materials and, consequently, greater prediction of the concrete's useful life.

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Resumen El objetivo de este estudio fue identificar los factores más frecuentemente relacionados con las grietas en los pezones y los distintos tratamientos utilizados para tratar este problema en madres que lactan, a través de una revisión de la literatura científica. La búsqueda se realizó utilizando las bases de datos: SCIENCE DIRECT EMBASE, PROQUEST, SCOPUS y SCIELO, publicados entre 2000 al 2018, además referencias bibliográficas citadas en los artículos seleccionados. Los términos utilizados fueron en inglés y español, estandarizados en los sistemas de descriptores para inglés y español, pero también se utilizaron términos no estandarizados identificados en algunos artículos. Los resultados arrojan que el uso de lanolina, compresas de agua tibia, leche materna extraída y la aplicación de menta son referidos como más efectivos para el trauma del pezón. Considerando los tratamientos encontrados, aquellos que contienen mejores efectos en la estimulación del crecimiento epitelial del pezón agrietado son: lanolina, la colágenas y apósitos de hidrogel. De acuerdo a lo anterior, no se recomienda un tratamiento por encima de otro, debido a que los métodos encontrados mostraron ser eficaces y beneficiosos tanto para el manejo del dolor como la disminución de trauma del pezón.

Abstract To identify the factors most frequently related to cracks in the nipples and the different treatments used to treat this problem in nursing mothers was do a review of the scientific literature. The search was conducted using the databases: SCIENCE DIRECT, EMBASE, PROQUEST SCOPUS and SCIELO, published between 2000 and 2018, and bibliographic references cited in some of the selected articles were added. The terms used were in English and Spanish, standardized in the descriptor systems for both languages, but non-standardized terms identified in some articles were also used. The results show that the use of lanolin, warm water compresses, expressed breast milk and the application of mint are the most effective for nipple trauma. Considering the treatments found, those that contain better effects in the stimulation of the epithelial growth of the cracked nipple are: lanolin, collagenase and hydrogel dressings. According to the above, one treatment is not recommended over another because the methods found to be effective and beneficial both for the management of pain and the reduction of nipple trauma.

Resumo O objetivo deste estudo foi identificar os fatores mais frequentemente relacionados às fissuras nos mamilos e os diferentes tratamentos utilizados para tratar esse problema em nutrizes, através de uma revisão da literatura científica. A busca foi realizada nas bases de dados SCIENCE DIRECT, EMBASE, PROQUEST, SCOPUS e SCIELO, publicadas entre 2000 e 2018, além de referências bibliográficas citadas nos artigos selecionados. Os termos utilizados foram em inglês e espanhol, padronizados nos sistemas descritores para inglês e espanhol, mas também foram utilizados termos não padronizados identificados em alguns artigos. Os resultados mostram que o uso de lanolina, compressas de água morna, leite materno extraído e a aplicação de hortelã-pimenta são referidos como mais eficazes no trauma mamilar Considerando os tratamentos encontrados, aqueles que contêm os melhores efeitos sobre a estimulação do crescimento epitelial do mamilo trincado são: pensos de lanolina, colágeno e hidrogel. De acordo com o exposto, um tratamento não é recomendado em relação a outro, porque os métodos encontrados se mostraram eficazes e benéficos para o manejo da dor e a redução do trauma mamilar

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Abstract In order to evaluate the volume of dentinal cracks taking into account the age of the dentin and the type of file system used for endodontic procedures, forty freshly extracted single-rooted lower incisive teeth presenting similar root volume, were divided into two groups according to the age of the patient: Group Young (18 - 30 years old) and Group Old (60 years old or more). Each specimen was scanned by microcomputed tomography (micro-CT) in three stages: (i) before any treatment, (ii) after endodontic treatment with Reciproc files (REC), and (iii) after subsequent endodontic retreatment. Each group was subdivided into two subgroups, according to the retreatment technique used: retreatment with REC or with ProTaper Universal Retreatment (PUR) files. For each subgroup, the images were analyzed for differences in the volume of dentinal cracks in the middle and apical thirds of the teeth , according to the dentin age. In both stages (before and after instrumentation), the micro-CT images of the old root dentin presented with higher volume of cracks than those of the young root dentin, statistical significance notwithstanding (p>0.01). The use of REC files appeared to have no statistically significant differences in the generation of cracks in any type of root dentin when compared with PUR files (p>0.01). When retreated with PUR, the old root dentin presented with a significantly higher volume of cracks (p<0.01) when compared with the old root dentin initially.

Resumo Para avaliar o volume de fissuras dentinárias levando em consideração a idade da dentina e o tipo de sistema de limas utilizadas para procedimentos endodônticos, 40 dentes unirradiculares, incisivos inferiores, apresentando similar volume radicular, recentemente extraídos foram divididos em dois grupos de acordo com a idade do paciente: Grupo Jovem (18 a 30 anos) e Grupo Idoso (60 anos ou mais). Cada espécime foi scaneada por microtomografia computadorizada (micro-CT) em três estágios: (i) antes de qualquer tratamento, (ii) após tratamento endodôntico com limas Reciproc (REC) e (iii) após subsequente retratamento endodôntico. Cada grupo foi subdividido em dois subgrupos, de acordo com a técnica de retratamento utilizada: retratamento com REC ou com lima ProTaper Universal Retreatment (PUR). As imagens foram analisadas quanto às diferenças no volume das fissuras dentinárias nos terços médio e apical dos dentes de acordo com a idade da dentina. Em ambos os estágios (antes e depois da instrumentação), as imagens de micro-CT da dentina radicular idosa apresentaram maior volume de trincas do que as jovens, sem significância estatística (p>0.01). O uso das limas REC mostram não ter diferença estatística significante na geração de fissuras, em qualquer tipo de dentina, quando comparadas às limas PUR (p>0.01). Quando retratada com PUR, a dentina radicular idosa apresentou um volume de trincas significativamente maior (p<0.01) quando comparado com a dentina radicular idosa inicialmente.

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In desiccated films, particularly with old paintings, molecular bonds may break to create intricate patterns of macroscopic cracks. The resulting directions of the cracks quantifiably enable an evaluation of the entropy and degree of disorder in the network. Experimental tests on prepared samples and a two-interacting-variables model allow the evolution of entropy to be tracked. Calculations were performed, primarily using data from the painting Girl with a Pearl Earring by Vermeer, revealing that the left side of the girl's face features a crack structure with higher entropy (or less order) than the right side. Other old paintings were considered. The extrapolation of experiments to these old paintings confirms that saturation still is not reached.

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INTRODUCTION: The aim of the present study was to evaluate the percentage frequency of dentinal micro-cracks observed after root canal preparation with TRUShape and Self-Adjusting File (SAF) systems by means of micro-computed tomography imaging analysis. A conventional full-sequence rotary system (BioRace) and a single-file reciprocation system (Reciproc) were used as reference techniques for comparison because of their known assertive cutting efficiency. METHODS: Forty anatomically matched mandibular incisors were selected, scanned at a resolution of 14.25 µm, and assigned to 4 experimental groups (n = 10), according to the preparation protocol: TRUShape, SAF, BioRace, and Reciproc systems. After the experimental procedures, the specimens were scanned again, and the registered preoperative and postoperative cross-section images of the roots (n = 70,030) were screened to identify the presence of dentinal micro-cracks. RESULTS: Overall, dentinal defects were observed in 28,790 cross-section images (41.11%). In the TRUShape, SAF, BioRace, and Reciproc groups, dentinal micro-cracks were visualized in 56.47% (n = 9842), 42.38% (n = 7450), 32.90% (n = 5826), and 32.77% (n = 5672) of the slices, respectively. All dentinal defects observed in the postoperative data sets were already present in the corresponding preoperative images. CONCLUSIONS: None of the preparation systems induced the formation of new dentinal micro-cracks.

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AIM: To evaluate the frequency of dentinal micro-cracks after root canal filling procedures with GuttaCore (GC), cold lateral compaction (CLC) and warm vertical compaction (WVC) techniques in mandibular molars using micro-computed tomographic analysis. METHODOLOGY: Thirty mesial roots of mandibular molars, with a type II Vertucci's canal configuration, were prepared to working length with a Reciproc R40 instrument and randomly assigned to one of the three experimental groups (n = 10), according to the technique used for root filling: GC, CLC or WVC. The GC group was filled with a size 40 GC obturator, whilst CLC and WVC groups used conventional gutta-percha cones. AH Plus sealer was used in all groups. The specimens were scanned at an isotropic resolution of 14.25 µm before and after root canal preparation and after root filling. Then, all pre- and postoperative cross-sectional images of the roots (n = 41 660) were screened to identify the presence of dentinal defects. RESULTS: Overall, 30.75% (n = 12 810) of the pre- + post-filling images displayed dentinal defects. In the GC, CLC and WVC groups, dentinal micro-cracks were observed in 18.68% (n = 2510), 15.99% (n = 2389) and 11.34% (n = 1506) of the cross-sectional images, respectively. All micro-cracks identified in the post-filling scans were also observed in the corresponding post-preparation images. CONCLUSION: Root fillings in all techniques did not induce the development of new dentinal micro-cracks.

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Abstract This study aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Universal (PTU) system and dentinal defects formation using micro-computed tomography (micro-CT) analysis. Forty mesial canals of mandibular molars with a type II Vertucci's canal configuration were scanned at an isotropic resolution of 14.16 µm. The sample was assigned to an experimental (n = 30) and a control (n = 10) groups, and the mesial canals were prepared with PTU system up to F2 instrument. The specimens from the experimental group were scanned and the cross-section images of the mesial roots, before and after preparation, were screened to identify the presence of dentinal defects. In the control group, the specimens were sectioned perpendicularly to the long axis of the root into 1-mm-thick slices (n = 80) and examined under optical microscope. Once a dentinal defect was detected, the slice was scanned through micro-CT. In the experimental group, dentinal micro-cracks were observed in 4,828 slices (24.04%). In all cross-section images, dentinal defects identified in the postoperative images were already present in the corresponding preoperative image. In the control group, 13 out of 80 slices (16.25%) had at least one dentinal defect visualized under stereomicroscopy, which was identified after a further micro-CT scanning. Micro-CT showed reliability as similar as optical microscopy in detecting dentinal defects, adding the possibility of tracking the dentinal tissue, before and after canal preparation, and providing a clear visualization of micro-cracks. Root canal preparation with PTU system did not induce the formation of new dentinal defects.

Resumo O objetivo deste estudo foi avaliar a relação de causa-efeito entre o preparo do canal radicular com o sistema ProTaper Universal (PTU) e a formação de defeitos dentinários usando a análise por micro-tomografia computadorizada (micro-CT). Quarenta raízes mesiais de molares inferiores com a configuração tipo II de Vertucci foram escaneadas com resolução isotrópica de 14.16 μm. A amostra foi distribuída em um grupo experimental (n = 30) e um grupo controle (n = 10), e os canais mesiais foram preparados com o sistema PTU até a lima F2. As amostras do grupo experimental foram escaneadas e as imagens de secção transversal das raízes mesiais, antes e após o preparo, foram analisadas ​​para identificar a presença de defeitos dentinários. No grupo controle, os dentes foram seccionados perpendicularmente em relação ao longo eixo da raiz em fatias de 1 mm de espessura (n = 80) e examinados ao microscópio óptico. Uma vez detectado um defeito dentinário, a fatia foi escaneada através da micro-CT. No grupo experimental, defeitos dentinários foram observados em 4.828 secções transversais (24,04%). Em todas as imagens de secção transversal, os defeitos dentinários após os procedimentos experimentais já estavam presentes na secção pré-operatória correspondente. No grupo controle, 13 das 80 fatias (16,25%) apresentaram pelo menos um defeito dentinário visualizado através do microscópio, o qual foi identificado em um escaneamento posterior. A micro-CT mostrou confiabilidade com a microscopia óptica para detecção e visualização dos defeitos dentinários, permitindo acompanhar o tecido dentinário antes e depois do preparo do canal. O preparo do canal radicular com o sistema PTU não induziu a formação de novos defeitos dentinários.

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AIMS: We evaluated whether reactive oxygen species (ROS) production and the plant antioxidant system are involved in the symbiotic interaction between bradyrhizobia and legumes infected by crack entry, without intracellular infection threads (IT) formation, such as Arachis hypogaea L. (peanut). The role of bradyrhizobial Nod factors (NF) in modulating the plants' oxidative burst was also analysed. METHODS AND RESULTS: Histochemical and quantitative procedures were used to detect ROS levels in inoculated and in NF-treated peanut roots. Increase in root H2O2 production was determined at 10 min postinoculation with Bradyrhizobium sp. SEMIA 6144 or after NF addition. ROS production was modulated by NF. From 15 to 30 min postinoculation, the compatibility of Bradyrhizobium sp.-peanut interaction depends mostly on the H2O2 detoxification via catalase. CONCLUSIONS: We demonstrated for the first time that the early events of the symbiotic interaction in legumes invaded by crack entry trigger an increase in ROS production (represented exclusively by a higher H2O2 content) in which NADPH-oxidase seems not to be involved. NF modulate this response by enhancing the plant antioxidant machinery, contributing to the creation of adequate conditions for symbiosis development. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data provide new insights into the mechanism involves in the symbiotic interaction that establish legumes infected by crack entry and suggest that ROS response shows differences compared with legumes invaded by IT formation.

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The Eucalyptus grandis logs temperatures were determined and correlated with the board's cracks during steaming. Thermocouples were inserted in the logs center, registering their temperatures during steaming at 90"C. The logs were sawed and the board's cracks measured. It was concluded that: (1) the logistic S-shaped curve explains the logs temperature variation; (2) the logs with diameter of 20 to <25, 25 to <30 and 30 to <35 cm presented, respectively, 84.2"C, 73.1"C and 45.8"C in the steaming; and (3) the cracks lengths significantly decreased in logs that reached the glass transition temperature.

As temperaturas em toras de Eucalyptus grandis, durante a vaporização, foram determinadas e correlacionadas com as rachaduras das tábuas. Nos centros das toras foram inseridos termopares e registradas suas temperaturas durante a vaporização à 90"C. As toras foram desdobradas e as rachaduras das tábuas mensuradas. Concluiu-se que: (1) o modelo estatístico sigmoidal logístico explica a variação da temperatura nas toras; (2) as toras com 20 a <25, 25 a <30 e 30 a <35 cm de diâmetro apresentaram, respectivamente, 84,2"C, 73,1"C e 45,8"C ao final da vaporização; e (3) as rachaduras foramsignificativamente menores nas toras que atingiram a temperatura de transição vítrea.

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