Improved Wood Species Identification Based On Multi-View Imagery of The Three Anatomical Planes

Background: The identification of tropical African wood species based on microscopic imagery is a challenging problem due to the heterogeneous nature of the composition of wood combined with the vast number of candidate species. Image classification methods that rely on machine learning can facilitate this identification, provided that sufficient training material is available. Despite the fact that the three main anatomical sections contain information that is relevant for species identification, current methods only rely on the transversal section. Additionally, commonly used procedures for evaluating the performance of these methods neglect the fact that multiple images often originate from the same tree, leading to an overly optimistic estimate of the performance. Results: We introduce a new image dataset containing microscopic images of the three main anatomical sections of 77 Congolese wood species. A dedicated multiview image classification method is developed and obtains an accuracy (computed using the naive but common approach) of 95%, outperforming the singleview methods by a large margin. An in-depth analysis shows that naive accuracy estimates can lead to a dramatic over-prediction, of up to 60%, of the accuracy. Conclusions: Additional images from the non-transversal sections can boost the performance of machine-learning-based wood species identification methods. Additionally, care should be taken when evaluating the performance of machine-learningbased wood species identification methods to avoid an overestimation of the performance.

Multi-Leaf Stone Masonry Walls in Egypt: A Legend

Multi-leaf stone masonry walls are a typical construction technique in architectural heritage in Egypt. The assessment, modeling, and strengthening of historic masonry walls of multi-leaf systems essentially require suitable knowledge of their construction technology, typology, geometrical characteristics, and the properties of their components. Within the current research project, a comprehensive structural survey of multiple-leaf walls of medieval historic buildings in Cairo was performed. The observation and statistical analyses allowed characterization of the transversal section of the surveyed walls, as well as examination and identification of the construction materials and techniques. The slenderness ratios of this type of wall, its blocks’ dimensions, the utilized connectivity between the inner and outer leaves, and leaves ratio were also investigated. Three construction hypotheses of multiple-leaf stone masonry walls are presented considering weak, thick, and monolithic core infill layers. The study’s objectives were to enlarge the knowledge of typology, morphology, and construction materials used in three-leaf masonry walls and provide a proper characterization as a prerequisite for determining the most suitable materials and techniques for further strengthening interventions.

Histological evaluation of the intestine of broiler chickens: comparison of three sampling methods

After the growth-promoting antibiotics prohibition, intestinal health became an increasing concern worldwide in poultry farming. The intestinal histological evaluation is an inexpensive technique that brings relevant information, but in poultry, the immediate process of intestinal post-mortem autolysis interferes directly on the samples quality for histological analysis hindering a precise diagnosis. This study aimed to standardize a technique for broilers’ intestines sample collection and fixation for histological analysis. Seven broiler chickens received a standard diet until 23 days of age when they were euthanized. Fragments of duodenum, jejunum, and ileum were collected using three methods: intestine strips, transverse section, and Swiss roll and posteriorly fixed in 10% buffered formalin and bouin solution. Tissue samples were submitted for histological (number of villi and viable villi per field) and morphometrical (villi height, crypt depth and villi:crypt ratio) evaluations and the results analyzed statistically. A significant high number of villi and viable villi per field in all regions was observed in the Swiss roll method. In the duodenum (p= 0.0066) and jejunum (p= 0.0058) an interaction between the Swiss roll method and the fixative buffered formalin was observed in the viable and number of villi per field, respectively. Regarding the morphometrical analysis significant differences were observed, in the jejunum villi height sampling by the methods Swiss roll (1,157.66 ± 148.25 μm, p= 0.0015) that showed the highest mean. Deeper crypt depths were observed in the jejunum (156.59 ± 15.68 μm, p= 0.0002) and ileum (131.13 ± 15.01 μm, p= 0.0006) collect by the Swiss roll method. An interaction between the bouin fixative was also observed in the jejunum (p= 0.0223) for this variable. Duodenum sampling by transversal section (12.68 ± 1.45 μm, p= 0.0076) was the only segment that had a significant difference for villi:crypt ratio, showing the highest mean. It can be concluded that the Swiss roll technique was the best method for morphometrical evaluation of the chickens’ intestines, since the highest counts of villi per field and viable villi per field were obtained, while buffered formalin was considered as the best fixative.

New Perspectives Regarding the Chip Formation Process of Ti-6Al-4V

The mathematical, physical and morphological characteristics of the chip formation process during cutting of Ti-6Al-4V will be analyzed and presented in this paper. In recent years titanium has received more attention due to their unique material properties, such as light weight by height strength, small deformation at high temperatures, low brittleness at low temperatures, and nearly no oxidation at high temperatures, but with the disadvantage that it is difficult to machine. A lot of investigations have been conducted to solve the complex process of machining. But the real complex phenomena at the cutting edge can’t be explained with the help of simplified models. This paper presents a new mathematical-physical model describing the process mechanics leveraging two kinds of friction to explain the metal behavior to strain and stress with self-hardening or softening effects, and the dynamic chip formation behavior due to strain rate discontinuity. All these influencing parameters have an interdependent relationship; thus, they cannot be analyzed separately. The resultant deformation process leads to a grid deformation pattern in the relevant region of the transversal section of a chip that can be used for comparing the theoretical solution with the experimental result. This deformation pattern is the only characteristic that will not disappear after machining. As long as the theoretical results are found to be in agreement with the experimental data of the produced segmented chip, we can be sure, that the models integrating the friction conditions, strain-stress, and metallurgical conditions are correctly developed. In approaching these problems, it is difficult to choose the relevant machining conditions, because a “quick-stop” test is difficult to produce. The reason might be the existing contact conditions at the tool-chip interface, which has an intensive connection due to the diffusion process. Therefore, two different cutting velocities were chosen with the hope that the diffusion is not too intensive; (one slow velocity with vc = 12.5 m/min and a higher velocity with vc = 100 m/min). In addition, a photomicrograph of a chip was taken for the validation process between theoretical and experimental results. Furthermore, the existing temperatures in the contacting zone as well as in the chip formation area could be developed and are discussed and presented in this paper.

Laser Defocusing Effect on the Microstructure and Defects of 17-4PH Parts Additively Manufactured by SLM at a Low Energy Input

In this paper, the microstructure, defects, hardness, and tensile strength of the 17-4PH specimens manufactured additively using the selective laser melting (SLM) technique were studied. The analyzed parts (10 mm size cubic specimens and tensile specimens) were manufactured with different defocus parameter values (−1, 0, +1 mm) in order to evaluate this effect with a low power laser (38 W). The study was carried out on three different sections of each cubic specimen, one perpendicular to the laser beam or SLM manufacturing direction (transversal section), and another two parallel to the laser beam direction (longitudinal sections). The specimens microstructures were analyzed with an X-ray diffraction technique, as well as optical, scanning electron, and transmission electron microscopes. Image J software was used to characterize the defects and phase ratio. In addition, hardness and tensile tests were performed according to the corresponding standards. The results show that the amount of austenitic phase and the average grain size varied with defocusing. The percentage of defective area was less than 0.25%. The analyzed defocus distance did not affect the number and average size of the defects. Adjusting the defocusing SLM parameter is important for manufacturing parts with good mechanical properties.

Colorimetry of Acacia mangium wood from plantations in northeast Brazil

The aim of this study was to evaluate color characteristics in wood samples from Acacia mangium from a homogeneous plantation in Bahia state, northeast Brazil, and also analyze the influence of anatomical section and radial position in the trunk on color response to contribute to information for the best use of the wood, such as, for example, the optimization of the performance of the pieces in sawmill through the most acceptable aesthetic form by the final consumer. Six trees with age of 14 years were cut. The species was identified by anatomical analysis at the Laboratory of Wood Anatomy of the Federal University of Paraná, comparing the sample collected with the authenticated material. A disc from the base of each tree was divided into six samples oriented in anatomical sections (transversal, radial and tangential), with dimensions of 20 × 20 × 30mm, named near pith, intermediate and near bark. A total of 36 samples were evaluated, 12 from each position. The colorimetric evaluation was performed with a CM-5 spectrophotometer. Data on lightness, green-red and blue-yellow chromatic coordinates were obtained, and values of saturation and hue angle were calculated. Acacia wood from planted forest is classified as olive color. Color parameters were influenced by anatomical section and radial position in the trunk, being found 44 for the transversal section, 55 for the tangential section and 57 in the radial for luminosity. Transversal sections had lower values in comparison to longitudinal surfaces and radial sections had higher luminosity than tangential sections. The near bark region presented lower values in most colorimetric parameters, except hue angle, in comparison with the intermediate and near pith regions, which was around 70 in the different positions of the wood.

Numerical assessment of effective width in steel-concrete composite box girder bridges

The present paper aims to determine numerically in the Abaqus® software the parameters that have the greatest influence on the effective width of steel-concrete composite box girder bridges. In the technical standards and in the literature, there is no specific recommendation for calculating the effective width in steel-concrete composite box girder bridge. As an alternative, the existing recommendations for steel-concrete composite I-girders are adopted. Therefore, in the absence of standards recommendations for steel-concrete composite box girder bridges, there is a need for an investigation into the distribution of stresses at the steel-concrete interface, because if the effective width was admitted incorrectly, may result in costly or even unsafe solutions. For this purpose, the effective numerical width of 160 models of steel-concrete composite box girder bridges was determined, in which the study variables were the configuration of the transversal section, the slab height, the span length and the elements arrangement in the cross section. After analyzing the results, it was proposed a recommendation to determine effective width of steel-concrete composite box girder bridges.

Thickness Estimation of TiO2-Based Nanotubes Using X-Ray Diffraction Techniques

TiO2-based nanotubes are a very promising material with many applications in solar cells, biomedical devices, gas sensors, hydrogen generation, supercapacitors, and lithium batteries, among others. Nanotube thickness is a very important property since it is related to electronic and surface mechanics. In this sense, transmission electron microscopy (TEM) can be used. However, it can be difficult to acquire a good TEM image because the transversal section of the nanotubes needs to be visible. In this work, TiO2-based nanotubes obtained via hydrothermal synthesis were studied using X-ray line profile analysis. Scherrer and Single-Line methods provided consistent results for the thickness of the nanotubes (≃ 5 nm) when compared with TEM. Additionally, Single-Line method was also applied to estimate the microstrain. The advantage of using XRD is given by the fact that it is a quick and statistically significant analysis when compared with TEM. The results show that XRD can be used as a rapid and reliable alternative for the thickness estimation of nanotubes.

Tourists' explicit and implicit attitudes towards conservation messages

PurposeThe purpose of the paper is to comparatively analyse explicit and implicit attitudes of visitors from sun and beach destinations towards two types of visual conservation messages: persuasive and prohibitive.Design/methodology/approachA quantitative empirical investigation of transversal section was carried out using a structured questionnaire. The geographic area of study is located in the Mexican Riviera Maya. The data was collected between the months of September 2016 to January 2017 from a total of 129 actual visitors of 12 different nationalities. Student t tests analyses were conducted to measure difference between explicit and implicit attitudes towards both types of messages.FindingsPersuasive visual messages of conservation shown to be effective at both, explicit and implicit, levels, while prohibitive ones were less effective than persuasive ones ay implicit level, corroborating that the persuasive messages are more effective than prohibitive ones, and that the implicit measurements tend to offer information that is not always revealed by explicit means.Practical implicationsResults can be exploited by those who are tasked with maintaining a delicate balance between tourism and the environment to achieve greater impact in developing the attitudes they need to show to their tourists, through the design and creation of persuasive conservation, even barrier, visual messages that are able to draw well to the visitors' subconscious and unconscious.Originality/valuePersuasive visual messages of conservation are produced to be effective at both explicit and implicit levels. However, inhibiting messages prove to be less effective with regard to persuasive messages at the implicit level, which reinforces that persuasive messages are more effective. Effective than the prohibitive ones and that the Implicit measurements offer information that is not always disclosed by explicit means. Persuasive messages aim at persuading and the recipient is not interested on the message. There is a possibility that the recipient will react negatively. Therefore, messages should be prepared using an indirect approach.