Large Plate Research Articles

Single-crystal elastic and thermodynamic properties of γ-LiAlO2

The elastic properties of γ-LiAlO2 were reinvestigated with the aid of resonant ultrasound spectroscopy (RUS) at ambient conditions. A strong discrepancy of the elastic coefficients derived by RUS can be found from the experimental results from the literature, where c12 and c13 deviate from our results by up to 60% (46 GPa). In contrast to the experimental cij from the literature, we can recognize a good agreement between the elastic coefficients derived from RUS and the values using density functional theory. The dielectric permittivity was measured on large plane-parallel plates, and the piezoelectric stress coefficient e123=0.14Cm−2 was derived from RUS measurements at ambient conditions. The heat capacity between 4 and 398 K has been obtained by microcalorimetry using a relaxation calorimeter. The Debye temperature was derived from heat capacity measurements (ΘCp=676 K) and RUS measurements (Θelastic=688 K).

A FastSLAM Approach Integrating Beamforming Maps for Ultrasound-Based Robotic Inspection of Metal Structures

We present a novel FastSLAM approach for a robotic system inspecting structures made of large metal plates. By taking advantage of the reflections of ultrasonic guided waves on the plate boundaries, it is possible to recover, with enough precision, both the plate shape and the robot trajectory. Contrary to our previous work, this approach takes into account the dispersive nature of guided waves in metal plates. This is leveraged to construct beamforming maps from which we solve the mapping problem through plate edges estimation for every particle, in a FastSLAM fashion. It will be demonstrated, with real acoustic measurements obtained on different metal plates, that such a framework achieves more accurate results, while the complexity of the algorithm is sensibly reduced.

Geodynamic models of short-lived, long-lived and periodic flat slab subduction

SUMMARY Flat slab subduction has been ascribed to a variety of causes, including subduction of buoyant ridges/plateaus and forced trench retreat. The former, however, has irregular spatial correlations with flat slabs, while the latter has required external forcing in geodynamic subduction models, which might be insufficient or absent in nature. In this paper, we present buoyancy-driven numerical geodynamic models and aim to investigate flat slab subduction in the absence of external forcing as well as test the influence of overriding plate strength, subducting plate thickness, inclusion/exclusion of an oceanic plateau and lower mantle viscosity on flat slab formation and its evolution. Flat slab subduction is reproduced during normal oceanic subduction in the absence of ridge/plateau subduction and without externally forced plate motion. Subduction of a plateau-like feature, in this buoyancy-driven setting, enhances slab steepening. In models that produce flat slab subduction, it only commences after a prolonged period of slab dip angle reduction during lower mantle slab penetration. The flat slab is supported by mantle wedge suction, vertical compressive stresses at the base of the slab and upper mantle slab buckling stresses. Our models demonstrate three modes of flat slab subduction, namely short-lived (transient) flat slab subduction, long-lived flat slab subduction and periodic flat slab subduction, which occur for different model parameter combinations. Most models demonstrate slab folding at the 660 km discontinuity, which produces periodic changes in the upper mantle slab dip angle. With relatively high overriding plate strength or large subducting plate thickness, such folding results in periodic changes in the dip angle of the flat slab segment, which can lead to periodic flat slab subduction, providing a potential explanation for periodic arc migration. Flat slab subduction ends due to the local overriding plate shortening and thickening it produces, which forces mantle wedge opening and a reduction in mantle wedge suction. As overriding plate strength controls the shortening rate, it has a strong control on the duration of flat slab subduction, which increases with increasing strength. For the weakest overriding plate, flat slab subduction is short-lived and lasts only 6 Myr, while for the strongest overriding plate flat slab subduction is long-lived and exceeds 75 Myr. Progressive overriding plate shortening during flat slab subduction might explain why flat slab subduction terminated in the Eocene in western North America and in the Jurassic in South China.

PEMBERDAYAAN SANTRI DALAM SIMULASI SIAGA BENCANA TSUNAMI DI MADRASAH TSANAWIYAH NURUL HUDA KABUPATEN ACEH BARAT

Indonesia is a country with high-risk potential for various types of disasters because Indonesia is located between three large tectonic plates of the earth, namely the Eurasian Plate, the Indo-Australian Plate and the Pacific Plate. West Aceh Regency is one of the districts included in the level of high hazard classification for tectonic earthquakes that can cause Tsunamis. The stage of empowerment community includes conducting the survey, the coordinating with principal of MTSS Nurul Huda, socialication of tsunami disaster and the simulation of tsunami disaster alert. In conducting the community empowerment, the students are enthusiasms to follow the socialization and the simulation of tsunami disaster aler.

License Plate Location Based on YOLOv3 and Vertex Offset Estimation

<p indent=0mm>Deep convolutional neural networks (DCNN) have been widely adopted in visual object detection as they can automatically learn effective image features and have strong generalization capabilities. Since the current mainstream visual target detection DCNN commonly output rectangular bounding boxes, they cannot effectively deal with the accurate location for tilted unconstrained license plates. To solve the problem, a solution was proposed and YOLOv3, as a specific DCNN, was trained by extending its output dimensions and establishing additional loss items about vertex offsets relative to the four bounding box corners, which empowers the trained model to output the rectangular bounding boxes and the license plate vertices meanwhile without sacrificing its high-efficiency performance. Experiments on CCPD, a widely used large scale unconstrained license plate dataset, illustrate that the proposed method can not only accurately predict the four vertices of a license plate, but also reach the precision above 99% in Base, Tilt and Weather subset. Moreover, this method can also be generalized to other application fields which require the target bounding box and key points output simultaneously and has promising application potential.

Flame retardant properties of waterborne epoxy intumescent coatings reinforced by polydopamine@KH560/carbon nitride/graphene ternary system

Firstly, the bio-inspired polydopamine (PDA) was coated on the surface of carbon nitride (CN), then used it (CNP) as nano-dispersant to improve the dispersion of graphene (Gr) in water on the basis of π-π interaction. After that, the KH560 was further grafted on the CNPG surface to improve the compatibility between inorganic hybrids and epoxy resin. The results of large plate experiments showed that the backside temperature of composite IFR coating containing CNPG@Si hybrids was significantly lower than that of other samples. Meanwhile, its expansion height after furnace test reached the maximum value (17.8 mm), which was greatly improved compared with the pure epoxy coating. Further, the maximum thermal decomposition temperature and the amount of char residue for the CNPG@Si/EP sample were significantly enhanced through the TGA test result. Besides, CNPG@Si based sample showed the lowest smoke density rating (SDR) due to its excellent smoke suppression performance. From the analysis of the morphology and composition of the char layer for CNPG@Si based sample, it can be seen that the introduction of Gr and CN increased the compactness of the char layer, and silicon network structures remained in the char layer after combustion, which effectively increases its strength and heat insulation effect.

Morphological descriptions of the nymph and adults of Ornithodoros clarki, the larva and nymph of Ornithodoros rondoniensis, with notes on their phylogenetic relationships.

Based on tick specimens collected recently in Mexico, Nicaragua, Panama and Brazil, we provide morphological descriptions of the nymph and adults of Ornithodoros clarki Jones & Clifford, 1972 from the first three countries, and the larva and nymph of Ornithodoros rondoniensis (Labruna, Terassini, Camargo, Brandão, Ribeiro & Estrada-Peña, 2008) from Brazil. Also, an analysis of mitochondrial 16S rDNA sequences was performed to analyze the phylogenetic relationships of these tick species. Adults and nymphs of O. clarki and O. rondoniensis are unique among the Argasidae family by presenting exceptionally large spiracular plates with small goblets, and an integument with smooth polygonal mammillae. However, these two species are morphologically distinct based on specific patterns of coxal folds, idiosomal mammillae and pilosity, and female genital flap. In contrast, the larvae of O. clarki and O. rondoniensis are morphologically identical, except for a general larger size of the former species; this slight difference is corroborated by Principal Component Analysis (PCA) by using 40 morphometric variables. Phylogenetic analyses including 16S rDNA partial sequences of different Ornithodoros taxa from Central and South America indicate that O. rondoniensis from Brazil diverges from O. clarki from Mexico, Nicaragua and Panama. However, phylogenetic distance separating both alleged species is similar or slightly lower than the distances depicted for conspecific populations of a few other Ornithodoros species. Nonetheless, our primary criterion to maintain O. rondoniensis as a valid species is because its adult and nymphal stages do present distinct morphological traits that easily distinguish these postlarval stages from O. clarki.

Pseudomonas aeruginosa biofilm killing beyond the spacer by antibiotic-loaded calcium sulfate beads: an in vitro study.

Introduction: Bacterial biofilms are an important virulence factor in chronic periprosthetic joint infection (PJI) and other orthopedic infection since they are highly tolerant to antibiotics and host immunity. Antibiotics are mixed into carriers such as bone cement and calcium sulfate bone void fillers to achieve sustained high concentrations of antibiotics required to more effectively manage biofilm infections through local release. The effect of antibiotic diffusion from antibiotic-loaded calcium sulfate beads (ALCS-B) in combination with PMMA bone cement spacers on the spread and killing of Pseudomonas aeruginosa Xen41 (PA-Xen41) biofilm was investigated using a “large agar plate” model scaled for clinical relevance. Methods: Bioluminescent PA-Xen41 biofilms grown on discs of various orthopedic materials were placed within a large agar plate containing a PMMA full-size mock “spacer” unloaded or loaded with vancomycin and tobramycin, with or without ALCS-B. The amount of biofilm spread and log reduction on discs at varying distances from the spacer was assessed by bioluminescent imaging and viable cell counts. Results: For the unloaded spacer control, PA-Xen41 spread from the biofilm to cover the entire plate. The loaded spacer generated a 3 cm zone of inhibition and significantly reduced biofilm bacteria on the discs immediately adjacent to the spacer but low or zero reductions on those further away. The combination of ALCS-B and a loaded PMMA spacer greatly reduced bacterial spread and resulted in significantly greater biofilm reductions on discs at all distances from the spacer. Discussion: The addition of ALCS-B to an antibiotic-loaded spacer mimic increased the area of antibiotic coverage and efficacy against biofilm, suggesting that a combination of these depots may provide greater physical antibiotic coverage and more effective dead space management, particularly in zones where the spread of antibiotic is limited by diffusion (zones with little or no fluid motion).

La fabbrica delle parole. Tecniche e sistemi di produzione del libro a stampa tra xv e xix secolo. By Andrea De Pasquale

The present book is a good idea, though precisely what readership it is targeting is far from clear. At one level—the best one—it is a simple pictorial history of the book‐making trades; it could also plausibly serve as a manual for university students which through contemporary illustrations—165 of them—illustrates the said processes with a modicum of commentary. Certainly it has been added to the printing/Bibliography manual section of my own bookcase. It is puzzling, however, to discover that none of the images is sourced, and so recognizing where they are from and the historical period they belong to is largely a matter of guesswork and the reader's own knowledge. Just under a quarter stem from the Diderot‐D' Alembert Encyclopédie (1751‐72), whose large plates, in order to accommodate them in a small volume such as this (21 cm), lose a lot of detail; the three earliest originate in the woodcuts of Jost Amman for the 1568 Eygentliche Beschreibung (or Panoplia in the Latin version), albeit, rather strangely, omitting those showing the papermaking and printing processes (too famous perhaps?); and a handful of others derive from the Hoepli manual by Salvadore Landi (1892). Otherwise the bulk of the nineteenth‐century images are taken from the periodical literature of the age—most of them unfamiliar to the present writer—and it would be valuable to know their original date and context of publication.

Energy-efficient heat exchanger design for indoor air quality in intercity buses

ABSTRACT In this study, a heat recovery exchanger was designed to provide indoor air quality (IAQ) and energy efficiency for intercity buses used in public transport. The heat recovery exchanger enabled the supply of fresh air into the bus cabin in an energy-efficient way to obtain a clean indoor environment. Two different simulations were conducted in the study. The first simulation was performed to determine the amount of required fresh air for the bus. The fresh airflow rate requirement was identified based on the carbon dioxide concentration inside the passenger bus. In the other simulation, the effect of the design parameters of a compact heat recovery exchanger with offset strip-fin on the effectiveness of the heat exchanger was investigated. The results showed that about 25% of the total ventilation should be supplied by fresh air in order to satisfy IAQ inside the bus cabin. They also showed that the effectiveness of the heat recovery exchanger increased with an increasing number of both plates and fins, larger plate dimensions, and decreasing fin offset length. Without impairing the IAQ, the maximum heat recovery was achieved with the highest effectiveness obtained for 20%–25% outside air ventilation.

Investigation of Bending of Anisotropic Plates with Inclusions with the Help of Singular Integral Equations

We consider the problem of bending of an anisotropic plate of constant thickness with rigid inclusions. The algorithm of its solution is constructed on the basis of reduction of the problem of bending of a multiply connected anisotropic plate with inclusions to the evaluation of the Lekhnitskii potentials for an auxiliary plane problem of the theory of elasticity with properly chosen elastic constants. To solve this auxiliary problem, we use the method of singular integral equations in the complex form. We consider the problems of bending for plates with inclusions subjected either to the action of moments at infinity (for infinitely large plates) or to transverse loading (for finite plates). We also present some examples of evaluation of stresses acting in the plates containing rigid inclusions of different shapes or systems of inclusions of this kind.

Scale-Reconstructible Structure from Motion Considering Amount of Refraction

In this paper, a method for scale-reconstructible Structure from Motion to improve the robustness of three-dimensional (3D) reconstruction with a thin plate is proposed. Scale-reconstructible Structure from Motion is a 3D measurement method with an absolute scale using a single camera and a refractive plate. However, previous studies need a large thick refractive plate to achieve scale-reconstructible Structure from Motion. To solve this problem, a weighting factor according to the amount of refraction for optimization of 3D reconstruction was designed. It was confirmed that optimization using the weighting factor is effective for the robust 3D reconstruction method by simulation experiment.

Evaluation of Structure Performance under Seismic Load with Non-Liner Time History on High-Rise Building Affected by Kendeng Fault Earthquake Simulation

Indonesia is a country located in the convergence of small plates and large plates. Furthermore, this causes Indonesia to be high potentially to earthquake hazards. The newest geological research published by Geophysical Research Letter (2016) shows the existence of Fault Kendeng, a fault stretches along 300 km from South Semarang, Central Java, to East Java with a movement of 0,05 millimeter per year [1]. As a result of its research, an evaluation using a non-linear time history analysis for structural buildings is necessary. The objective of this study is to evaluate structural buildings using a non-linear time history analysis. This study applies DSHA (Deterministic Seismic Hazard Analysis) method to obtain acceleration time history on bedrocks. Since the record of ground movement in Indonesia is limited, the attenuation function equation used to scale and match other country’s time acceleration history data. SSA (Site-Specific Analysis) is used to propagate earthquake acceleration from bedrocks to the surface. The earthquake acceleration on the surface generates as the earthquake load on the buildings. The results of Kendeng fault earthquake simulation using non-linear time history analysis shows that column members capacity is more robust than beam members capacity which the beam collapse mechanism occurs initially. From the maximum total drift ratio result, when the Kendeng fault earthquake occurs, the building structure performance level is at collapse prevention level Based on ATC-40 [2]. This research result shows that 96,7% of plastic hinge has not yielded. However, some elements are already damaged. Since most damage members are column, then it may require column strengthening to enhance maximum performance level at life safety condition category.

Non-destructive Testing Assisted by Six-Axis Manipulator Based on POE Formula

At present, aluminum plates are widely used in aerospace, machinery, and other fields because of their light weight, good manufacturability, and strong corrosion resistance. However, during long-term use, defects that will affect the structural strength such as cracks are easy to appear. Therefore, it is necessary to conduct automatic non-destructive testing of large metal plates to determine the location, size, and structural damage to their defects. Compared with manual detection, automated detection has many advantages such as high detection efficiency, high repeatability, strong flexibility, and low labor intensity. Based on the spinor theory, this paper uses the product of exponentials (POE) to model the kinematics of the Aubo-i5 manipulator and obtain the positive kinematics equations, which are compiled by analytic geometry and algebraic methods combined with Paden-Kahan subproblems and matrix theory. The inverse kinematics algorithm of the 6R manipulator is based on this model. An automated non-destructive testing system including a robotic arm and ultrasonic phased array testing equipment was built. At the same time, a robotic arm simulation platform was built based on ROS, and the inverse kinematics algorithm was used to control the robotic arm through the MoveIt!. The angle error can be controlled within 2.5°.

Coherent surface structure induces unique epitaxial overgrowth of metastable octacalcium phosphate on stable hydroxyapatite at critical fluoride concentration

The phase transformation from soluble calcium phosphates to less-soluble hydroxyapatite (HAP) is a thermodynamically natural route. This process is irreversible, and effective use of poorly reactive HAP to repair teeth that have no cellular metabolism remains challenging. However, this thermodynamically controlled transformation may apparently be reversed through the fast nucleation and growth of metastable phases, leading to a reactive HAP surface. Here, the assembled HAP-nanorod phase is demonstrated to change into the metastable octacalcium phosphate (OCP) phase in a calcium phosphate solution containing 0.8 ppm fluoride. Grown OCPs display parallel surface streaks and their 11¯0 and 00l (l: odd) electron-diffraction spots are often not visible. The streaked, elongated OCP gradually grows into large plates with flat surfaces that exhibit an intense11¯0 spot. Crystal-structure models reveal that the unique epitaxial overgrowth of OCP on HAP occurs since both materials share coherent {100} faces, resulting in the distinctive disappearance of 11¯0 and 00l OCP spots. A polysynthetic twin model that reliably explains this disappearance is proposed for the growth of OCP. This apparent reverse phase transformation produces hybrid calcium phosphates consisting of HAP cores and highly reactive outer OCP layers that are promising for the repair of dentin caries. Statement of significanceThis paper demonstrates important and interesting finding regarding formation of calcium phosphates in relation to their crystal structures.We first show that hydroxyapatite (HAP), the major constituent of human teeth and bone, can reversely change to its precursor, octacalcium phosphate (OCP), contrary to thermodynamic-stability rule. This apparent reverse phase transformation occurs through sharing the coherent {100} faces of both materials under controlled fluoride concentration. Nanoscale similarity of two crystal surfaces enables structurally shared epitaxial overgrowth of OCP on HAP aided by faster growth rate of OCP than that of HAP.This reaction produces hybrid crystal consisting of outer OCP and core HAP, that has not been known before and is able to be applied to dentin caries repair.

Experimental study of wave force on large steel plate cylinder structure

Steel plate cylinder is more and more widely used as breakwater and revetment structure, but the existing design codes related to breakwater lack the distribution of wave force on the outside of steel plate cylinder under the action of waves. In this paper, the 2-D wave physical model experiment is used to test the pressure distribution of large diameter steel plate cylinder structure under wave action. The results show the wave distributions along different cross sections of the facing side during the crest and trough action. It provides the necessary theoretical basis and technical support for the design of large diameter steel plate cylinder.

Photoelectric Detection of Hole Shape and Size for Large Plate Parts

The measurement of hole shape and size of large plate parts has always been a technical problem. The article proposes a technology to use non-contact photoelectric detection technology for online detection of the shape and position of large plate-shaped workpieces. The detection principle is: the control system controls the photoelectric detection system to move in a straight line along the guide rail at a uniform speed, and the large plate-shaped workpiece the hole shape and size are measured, and the lighting system moves synchronously with the photoelectric detection system to provide the light source for it. The images collected by the photoelectric detection system are processed through digital image processing and image splicing technology to realize the hole shape and size of large plate workpieces. Non-contact measurement.

On radial, circumferential, and spiral cracks in fractured glass plates

AbstractThis is a fractographic case study of a mechanically loaded glass plate that formed a remarkable spiral crack when the plate fractured. Common radial and circumferential cracking in disks and plates in general are first reviewed. The exceptional spiral crack is then analyzed. The origin of failure was an unusual flaw on the nominal compression side of the plate. The complex spiral fracture pattern has been observed in other large plate glass fractures that break under blunt impact conditions. Spiral cracks can form and propagate from flaws on the front side of a flexed plate that is rigidly supported at its rim or, alternatively, is supported from underneath and has a large overhang.

A new species of Loricaria (Siluriformes: Loricariidae) from the Turiaçu River basin, Eastern Amazon region, Brazil.

A new species of Loricaria is herein described from the Turiaçu River basin, Eastern Amazon region, Maranhão state, Brazil, within the Maranhão Hydrological Unit (MHU). Loricaria turi differs from its congeners mainly by the following combination of characters: abdominal plate development confined to the posterior median region, pectoral girdle mostly naked, with cluster of plates near pectoral fin bases; large eyes (minimum orbital diameter 16.2-20.7% of HL and maximum orbital diameter 19.8-24.0% of HL), 214.4 mm of maximum standard length, and large basicaudal plate (16.6-29.2% of HL). The description of this new species strengthens the hypothesis that the Maranhão Hydrological Unit (MHU) is a possible area of endemism for freshwater fishes and contributes to the knowledge of the freshwater fish diversity and composition of the region.

Effects of basal drag on subduction dynamics from 2D numerical models

Abstract. Subducting slabs are an important driver of plate motions, yet the relative importance of different forces in governing subduction motions and styles remains incompletely understood. Basal drag has been proposed to be a minor contributor to subduction forcing because of the lack of correlation between plate size and velocity in observed and reconstructed plate motions. Furthermore, in single subduction system models, low basal drag leads to subduction behaviour most consistent with the observation that trench migration velocities are generally low compared to convergence velocities. By contrast, analytical calculations and global mantle flow models indicate basal drag can be substantial. In this study, we revisit this problem by examining the drag at the base of the lithosphere, for a single subduction system, in 2D models with a free trench and composite non-linear rheology. We compare the behaviour of short and long plates for a range of asthenospheric and lithospheric rheologies. We reproduce results from previous modelling studies, including low ratios of trench over plate motions. However, we also find that any combination of asthenosphere and lithosphere viscosity that produces Earth-like subduction behaviour leads to a correlation of velocities with plate size, due to the role of basal drag. By examining Cenozoic plate motion reconstructions, we find that slab age and plate size are positively correlated: higher slab pull for older plates tends to be offset by higher basal drag below these larger plates. This, in part, explains the lack of plate velocity–size correlation in observations, despite the important role of basal drag in the subduction force balance.