Blocks Of Different Sizes Research Articles

Quantitative Risk Assessment of Rock Instabilities Threatening Manazan Caves, Karaman, Türkiye

Located in the southern part of Central Anatolia Region, Manazan Caves is situated in the east of Yeşildere Valley. It is a five-storey mass dwelling carved into a human-made high rock mass. Although there are no exact data to determine when the caves were carved, it is assumed that the caves were carved and settled in the Byzantine period during the 6th − 7th centuries. The geological and geotechnical data analyses were conducted in Manazan Caves. As a result of these analyses, it was observed that rock blocks of different sizes fell into the field in various times of the year, and there were instabilities in some individual rock blocks. In the study area, the movement mechanisms of rock slopes due to discontinuity were analysed by using various computer programs (DIPS, RockFALL, GEO5); and in order to ensure the safety of life and property and to protect this heritage cave, the current rockfall potential and risk along with slope instabilities were determined, and the fundamental prevention measures to be taken were discussed.

A multi‐level approach to predict the seismic response of rigid rocking structures using artificial neural networks

AbstractThis paper explores the use of Artificial Neural Networks (ANN) for the rocking problem. The paper adopts rigid rocking blocks of different sizes and slenderness, which undergo rocking motion without sliding and bouncing when subjected to recorded earthquakes. This research focuses on the cases where the blocks overturn or safely return to their initial (rest) position at the end of the ground shaking. An ANN model is trained to efficiently categorise the response into overturning or safe rocking using the structural parameters, ground motion characteristics, and the coefficient of restitution as input. The results show the substantial contribution of velocity and frequency characteristics of the ground motion to overturning. In addition, ANN is used to predict the response amplitude and identify the most critical input variables that govern safe rocking. The analysis reveals that rocking amplitude is governed by a combination of duration, frequency, and intensity characteristics of the ground excitation. Interestingly, the maximum incremental velocity (MIV), a novel intensity measure for the rocking literature, shows a substantial correlation with the rocking amplitude. In this context, this paper proposes closed‐form expressions using the most influential input variables to provide a quick, yet adequately accurate, response prediction. Finally, this study pays special attention to the contribution of the coefficient of restitution, which, in general, is less critical to the peak safe rocking response, while it becomes more important to the overturning response.

A new cube movement test for verification of simulations of contact processes of blocks of different size in geological hazards

AbstractIn many geological hazards, such as landslides, a large number of irregular blocks start moving. Their interaction on the way down renders prediction of disaster scopes difficult. To study this process and to provide a novel method for validation and calibration of numerical tools for its simulation, a cube movement test is designed. The goal of this research is to obtain patterns of movement of cubes, starting from different initial stacking arrangements. Cubes of four sizes are inserted into a hollow cylinder. Their distribution after lifting the cylinder is determined. Three categories of tests refer to three different strategies of filling the cubes into the cylinder. In order to simulate cube movement tests, a numerical tool is developed in the framework of the continuum–discontinuum element method (CDEM). The contact between the individual cubes is modeled by the contact‐pairs‐based algorithm. Both the contact state and type are detected by determining the half‐space relation between contact pairs. The final positions of the cubes are strongly related to their initial arrangement. The latter is different in every test, even if the same strategy is used to fill the cubes into the cylinder. It is found that at least 20 experiments/simulations are required to obtain statistically representative results. The new test provides valuable data for validation of numerical tools used for the simulation of mass movement processes. The proposed numerical method captures the complicated movements of blocks.

An adjustable magnetic type resonant multimodal inertial impact motor

The conventional asymmetric inertial impact motors are driven by using the difference in inertial impact forces in the forward and reverse directions, implemented by using asymmetric drive signals, clamping blocks of different sizes or different materials, etc. An adjustable magnetic force type resonant inertia impact motor has been designed, assembled, and tested. The novel motor features a simple and compact structure, allowing for the attainment of different output performance by adjusting the magnetic force to meet various working requirements, and the reverse motion can be easily achieved by simply altering the orientation of the magnet located at the end of the piezoelectric vibrator, without requiring any additional structure The part of the motor’s structure was simulated and optimized using the finite element analysis software COMSOL6.0, with the first and second order vibration modes selected as the working mode. The experimental platform has been established to verify the working performance of the motor. Experimental results demonstrate that, under excitation voltage of 120 VP–P and frequency of 163 Hz, the maximum speed achieved by the motor prototype is 36.55 mm s−1, with maximum load capacity of 320 g, and under excitation voltage of 40 VP–P and frequency of 928 Hz, the minimum step of the prototype reaching up to 134 nm. The motor proposed in this paper features an innovative asymmetric strong magnetic design, enabling high speed and load through the large amplitude of the piezoelectric vibrator in first-order vibration mode. As the amplitude gradually decreases in second and higher order modes, this motor achieves higher displacement resolution, making it has potential applications in high precision positioning and medical fields.

Interfacial microstructure and mechanical properties of Si3N4/Invar joints using Ag–Cu–In–Ti with Cu foil as an interlayer

Abstract Si3N4 and Invar alloy brazed joints were achieved using two types of Ag-based interlayers: a Ag–Cu–In–Ti foil and a Ag–Cu–In–Ti/Cu/Ag–Cu multi-interlayer. The results showed that when only using a single Ag–Cu–In–Ti filler, the wave-shaped Fe2Ti + Ni3Ti intermetallic compounds are concentrated in the middle of the brazing seam. When adding Cu as the interlayer, the dissolution of the Cu interlayer formed a large number of Cu(s,s) blocks of different sizes in the brazing seam, which hindered the concentrated distribution of Fe2Ti + Ni3Ti intermetallic compounds in the brazing seam. As a result, Fe2Ti and Ni3Ti were dispersedly distributed in the brazing seam, increasing the shear strength of the brazed joint. The shear strength of brazed joints was increased by 82 % compared to joints brazed with a single Ag–Cu–In–Ti filler when the Cu interlayer was added.

Biomedical image segmentation algorithm based on dense atrous convolution.

Biomedical images have complex tissue structures, and there are great differences between images of the same part of different individuals. Although deep learning methods have made some progress in automatic segmentation of biomedical images, the segmentation accuracy is relatively low for biomedical images with significant changes in segmentation targets, and there are also problems of missegmentation and missed segmentation. To address these challenges, we proposed a biomedical image segmentation method based on dense atrous convolution. First, we added a dense atrous convolution module (DAC) between the encoding and decoding paths of the U-Net network. This module was based on the inception structure and atrous convolution design, which can effectively capture multi-scale features of images. Second, we introduced a dense residual pooling module to detect multi-scale features in images by connecting residual pooling blocks of different sizes. Finally, in the decoding part of the network, we adopted an attention mechanism to suppress background interference by enhancing the weight of the target area. These modules work together to improve the accuracy and robustness of biomedical image segmentation. The experimental results showed that compared to mainstream segmentation networks, our segmentation model exhibited stronger segmentation ability when processing biomedical images with multiple-shaped targets. At the same time, this model can significantly reduce the phenomenon of missed segmentation and missegmentation, improve segmentation accuracy, and make the segmentation results closer to the real situation.

Characteristics of central cortex and upper-limb flexors synchrony oxygenation during grasping in people with stroke: a controlled trial study protocol.

Upper limb motor impairment is a common consequence of stroke, and the effectiveness and underlying mechanisms of rehabilitation therapy for improving upper limb function remain uncertain. Functional near-infrared spectroscopy, a reliable wearable neuroimaging technique, holds promise for investigating brain activity during functional tasks. This study aims to explore the synchronous oxygenation characteristics of the central cortex and upper-limb flexors during a grasping task and investigate the rehabilitation mechanisms of upper limb motor function in individuals with stroke. Participants with stroke who demonstrate the ability to grasp and lift cubic wood blocks of different sizes (2.5cm3, 5cm3, and 10cm3) using their affected hand will be divided into three groups: A, B, and C. Each group will consist of twenty stroke patients, resulting in a total of sixty participants with stroke. Additionally, twenty matched healthy subjects will be enrolled as a control group. Comprehensive assessments will be conducted before and after the intervention, including blood oxygen parameter monitoring of the cerebral cortex and upper limb flexors using fNIRS during the grasping task. Other assessments will include MyotonPRO, the Modified Ashworth Scale, the upper extremity section of the Fugl-Meyer Assessment, the Action Research Arm Test, and the Modified Barthel Index. The study will be undertaken between January 2024 and September 2025. The results of this trial will provide an in-depth understanding of the Characteristics of central cortex and upper-limb flexors synchronous oxygenation during grasping task and how it may relate to the rehabilitation mechanism of upper limb motor function in people with stroke. https://www.chictr.org.cn, identifier ChiCTR2400080619.

Characteristics structures of the mélange zones in the Ukrainian Carpathians

Mélange is characterized by the block-in-matrix fabric in which rigid blocks of different sizes, lithologies, and ages are distributed in a ductile matrix. Though mélange is a significant component of orogenic belts, in the Ukrainian Carpathians, mélanges of tectonic origin have not been reported. We have described the mélange zones widespread in the Pieniny Klippen Belt, Marmarosh Klippen Zone, and the inner nappes of the Outer Ukrainian Carpathians, as well as the typical deformation structures developed within them.
 The mélange matrix is characterized by a scaly fabric formed by cleavage surfaces and somewhere arranged in S-C structures. Lenticular clasts within the matrix show their long axis aligned to the tectonic foliation. Rotation of the boudins occurs against the shear direction following the formation of the S-C structures. The rigid clasts somewhere demonstrate sigma-type rotation structures. Some blocks within the mélange are highly fractured up to tectonic breccias.
 The study of tectonic slicken-sides and other deformation structures within the Pieniny belt demonstrates the presence of regular stress fields correlated with the geodynamics of the Carpatho-Pannonian region. The main stress field indicates the SW-NE regional compression related to the formation of Carpathian nappes and S-N — trending dextral strike-slip faults. Our study in the Priborzhava quarries records the Oash right-lateral strike-slip fault zone. In the Pieniny Klippen Belt some oblique normal faults of the Carpathian direction are related to the Transcarpathian Depression formation. The study showed that the mélange zones in the inner part of the Ukrainian Carpathians were formed largely due to strike-slip movements. In contrast, in the outer part of the Carpathian orogen, they formed mainly due to thrusting.

An efficient hardware architecture of integer motion estimation based on early termination and data reuse for Versatile video coding

The integer motion estimation (IME) involves high computational complexity and large amount of computation data due to the variable block sizes, and it is one of the most critical bottlenecks in video coding. The traditional algorithm for integer motion estimation loses search accuracy when simplifying the motion search process, or it becomes complex to pursue search accuracy, which is not conducive to video encoding and transmission. This paper presents a data reuse algorithm based on search window division, block splitting, the arrangement of search points in the Test Zone (TZ) search algorithm and block division. which divides pixel blocks of different sizes into several 8x8 pixel blocks and then reuses the overlapping 8x8 pixel blocks between adjacent search points of the Test Zone (TZ) search algorithm to reduce hardware resource consumption. By comparing the Sum of Absolute Differences (SAD) values of left and top pixel blocks with current pixel block, the integer motion estimation (IME) can be terminated in advance, reducing the computation complexity of integer motion estimation by over 70 %. Furthermore, the paper also presents a hardware architecture based on the data reuse algorithm, which can process 7680 × 4320@60fps videos at an operating clock frequency of 182.99 MHz, with lower resource consumption compared to similar hardware designs.

Discontinuous Galerkin method for the shallow water equations on complex domains using masked block-structured grids

We evaluate masked block-structured grids for ocean domains which allow to represent small-scale geometric features without resorting to very small blocks or excessive mesh resolution. The considered approach aims to combine the geometric flexibility of unstructured meshes with the computational efficiency of stencil-based discretizations and is implemented and tested in a quadrature-free discontinuous Galerkin shallow water solver. We investigate the accuracy and the computational performance of the scheme on a range of realistic ocean domains meshed with blocks of different size and provide some comparisons to results obtained on unmasked block-structured grids and unstructured meshes.

Responses of a System Comprising a Rigid Block with Resettable Sliding Key Under Base Excitation

The relatively uncontrolled dynamic behavior of a rigid block resting on a flat surface under ground motion has been well studied. In contrast, a block with a gently inclined V- or W-shaped sliding key would ensure dynamic self-centering or resetting performance under various seismic conditions. To better understand the nonlinear responses of rigid blocks having this type of interface where both rocking and sliding movements are possible, an event-based algorithm is put forward to cover various types of motions, including the transition stages between different types of motions. A comprehensive study is carried out to examine the dynamic responses of blocks of different sizes and aspect ratios. Moreover, the simplified pure rocking model and pure sliding model are also adopted to obtain rough estimates of dynamic response for comparison. The results show that the simplified models are reliable for some special cases only, e.g. squat blocks and slender blocks. The study also evaluated the influence of the coefficient of friction and slope inclination on the resetting capabilities of typical sliding-prone and rocking-prone systems. For those cases that are prone to toppling or excessive sliding under strong earthquakes, the provision of vertical post-tensioning can effectively ensure stability and resetting performance. Such findings provide insight into the performance of precast segmental bridge columns with resettable sliding joints.

Memory-efficient multi-scale residual dense network for single image rain removal

Outdoor photography is greatly affected by bad rainfall, which degrades the quality of captured images and hinders practical application. In response to the above problems, we propose a memory-efficient multi-scale residual dense network (MMRD-Net) for single image rain removal. Firstly, we use a combination or fusion of extended convolution blocks of different sizes to accurately extract multi-scale features of rain streaks and raindrops while retaining rich local detail. Secondly, we add attention modules to the residual block, which performs adaptive operations on rainfall and non-rainfall areas to extract more and more accurate image features and details of rain streaks and raindrops. During this period, we opened up a space for shared use by all the concatenation layers in the network, which reduces the memory consumption of the network. It allows for better aggregation of stormwater features at multiple levels and also allows for faster convergence of the network. Finally, we tested on both synthetic and real datasets to obtain subjective results and objective evaluations. The experimental results show that the performance of our algorithm is good and robust for joint rain removal tasks of different densities. Our algorithm outperforms twelve other different classical algorithms in terms of its ability to remove rain streaks. It can produce visually sharper deraining images and the enhanced visibility of the images is effective for computer vision applications (Google Vision API).

Super-resolution microscopy based on wide spectrum denoising and compressed sensing

WSD can effectively remove random noise of a raw image from very low density to ultra-high density fluorescent molecular distribution scenarios. The size of the raw image that WSD can denoise is subject to the used measurement matrix. A large raw image must be divided into blocks so that WSD denoises each block separately. Based on traditional single-molecule localization and super-resolution reconstruction scenarios, wide spectrum denoising (WSD) for blocks of different sizes was studied. The denoising ability is related to block sizes. The general trend is when the block gets larger, the denoising effect gets worse. When the block size is equal to 10, the denoising effect is the best. Using compressed sensing, only 20 raw images are needed for reconstruction. The temporal resolution is less than half a second. The spatial resolution is also greatly improved.

An Experimental-Theoretical study on heat transfer aspects of indirect Sublimation, for application in CO2-based refrigeration systems

Recent advances in CO2-based refrigeration systems have made it necessary to derive heat transfer correlations for the design of the corresponding industrial equipment. The current study focuses on the derivation of such correlation for indirect sublimation, whereby a material is sublimated on a hot surface by transferring energy to it via a conduction mechanism. We took an experimental-theoretical approach to investigate the subject in the case of constant wall temperature. An apparatus with real-time temperature and weight display was built to sublimate the dry ice blocks of different sizes, with circular and rectangular geometries. When the temperature of the hotplate was changed from −30 to 200 °C, the heat transfer coefficient “hsub” decreased from 126 to 70 W/m2K. Such coefficients are about one-fourth of the corresponding values in flow (direct) sublimation. Weight and area of the block had positive/negative effects on heat transfer, respectively. In the theoretical part, two “linear-gradient” and “semi-analytical” models were developed. The more accurate semi-analytical model could estimate “hsub” with 6.4 and 21.3 % average error in circular and rectangular geometries. Linear-gradient was analytic, with respective errors of 17.3 and 25.9%.

Effective Hard-Sphere Repulsions between Oleate-Capped Colloidal Metal Oxide Nanocrystals.

Nanocrystal interactions in solvent influence colloidal stability and dictate self-assembly outcomes. Small-angle X-ray scattering is used to study how dilute oleate-capped In2O3 nanocrystals with 7-19 nm core diameters interact when dispersed in a series of nonpolar solvents. Osmotic second virial coefficient analysis finds toluene-dispersed nanocrystals in this size range interact like effective hard spheres with diameters comprising the inorganic core and a ligand-solvent corona with a core-size independent thickness. Hard-sphere-like structure factors are similarly observed for nanocrystals with a 9.7 nm core diameter dispersed in all the solvents investigated. Nanocrystal hydrodynamic diameters from dynamic light scattering measurements correlate with thermodynamic diameters obtained from the osmotic second virial coefficient analysis for all samples. The ability to prepare nanoscale building blocks of different sizes, and dispersed in a variety of solvents, with effective hard-sphere repulsions provides a foundation for assembly, where secondary linking or depletant molecules can be deliberately added to customize interactions to form superstructures such as gel networks or superlattices.

Fast colored video encryption using block scrambling and multi-key generation

Multimedia information usage is increasing with new technologies such as the Internet of things (IoT), cloud computing, and big data processing. Video is one of the most widely used types of multimedia. Videos are played and transmitted over different networks in many IoT applications. Consequently, securing videos during transmission over various networks is necessary to prevent unauthorized access to the video's content. The existing securing schemes have limitations in terms of high resource consumption and high processing time, which are not liable to IoT devices with limited resources in terms of processor size, memory, time, and power consumption. This paper proposed a new encryption scheme for securing the colored videos. The video frames are extracted, and then, the frame components (red, green, and blue) are separated and padded by zero. Then, every frame component (channel) is split into blocks of different sizes. Then, the scrambled blocks of a component are obtained by applying a zigzag scan, rotating the blocks, and randomly changing the blocks' arrangements. Finally, a secret key produced from a chaotic logistic map is used to encrypt the scrambled frame component. Security analysis and time complexity are used to evaluate the efficiency of the proposed scheme in encrypting the colored videos. The results reveal that the proposed scheme has high-level security and encryption efficiency. Finally, a comparison between the proposed scheme and existing schemes is performed. The results confirmed that the proposed scheme has additional encryption efficiency.

Meiotic Analysis of Gomphidae Species Sheds Light on the Large X Chromosome of the Family (Anisoptera, Odonata)

In most Anisoptera families, the modal diploid number is 25 in males (24 autosomes + X), and the X chromosome is one of the smallest elements of the complement. The family Gomphidae is an exception, as it has a modal diploid number of 23 (22 + X), and the X chromosome is the largest of the complement and of medium-to-large size in many species. We studied the meiosis of three gomphid species from Argentina: Aphylla cf. distinguenda (Campion, 1920), Phyllocycla propinqua Belle, 1972 and Phyllocycla sp. Chromosome number is 2n = 23, n = 11 + X, except for Phyllocycla propinqua, showing n = 10 + X. The X chromosome of these species is medium-sized and presents heteropyknotic blocks of different sizes. Despite the small number of gomphid species analysed, there is a clear trend of increasing size of the X chromosome with the increasing amount of heterochromatin. Our results, together with those from the literature, suggest that its large size might have been due to a progressive accumulation of repetitive DNA and heterochromatinisation and not to fusion, as previously suggested. This led us to propose that the ancestral number coincided with the modal number of Gomphidae. A revision of the derived sex-determining systems in Odonata is also provided.

Three-dimensional assessment of palatal area changes after posterior crossbite correction with tooth-borne and tooth bone-borne rapid maxillary expansion.

To assess and compare the three-dimensional treatment changes in palatal surface area and volume using either tooth-borne (TB) or tooth bone-borne (TBB) rapid maxillary expanders and to evaluate the long-term effects of the two devices and the incidence of the relapse between the groups. A total of 52 consecutive patients who met the eligibility criteria were recruited and allocated to either the TB group, mean age 9.3 years (standard deviation [SD], 1.3), or the TBB group, mean age 9.5 years (SD, 1.2). Study casts were taken before, directly after, 1 year after, and 5 years after expansion. Study casts were digitized, superimposed, and evaluated. Participants were randomly allocated in blocks of different sizes using the concealed allocation principle in a 1:1 ratio. Changes in palatal volume, palatal surface area, and palatal projection area within and between the groups up to 5 years after expansion followed the same pattern and did not show any statistically significant differences between the groups. Relapse was seen in 15% of the patients. It seemed that open-bite and a Class III growth pattern could be assumed as prognosis-deteriorating factors in regard to stability of the treatment. There were no significant differences between the TB and TBB groups in palatal volume, palatal shell area, or palatal projection area directly after expansion or at 1 year and 5 years after expansion, which implies that the two devices gave rise to the same immediate and long-term outcomes.

Not just Good Chemistry

Abstract Chemistry as a science and an industrial sector plays a determining and indispensable role in all parts of our lives as it is the only science that can change matter (apart from nuclear physics). What we call a chemical product is often highly complex; elements and chemicals are most often applied as mixtures in products. For example, there are several hundred grades of steel (i.e. iron alloys) marketed. Electronics relies on many complex materials. Other examples of products are pesticides, pharmaceuticals, biocides, laundry detergents, personal care products and many others composed of several chemicals each. Estimates indicate that the number of chemicals in use today exceeds 340 000 worldwide. There are many kinds of polymers. The polymers themselves are made-up by manifold building blocks of different size, stereochemical arrangement, functional groups, branched or interlinked segments, etc. Today more than 10 500 plastic-related additives are in use. Often during synthesis, manufacturing, and use, and at the end of their lives, all these materials and products are transformed (“degraded“), resulting in new chemical entities of often unknown properties, impact on the product and toxicity. In other words, at all stages of the chemical products lifespan there is enormous chemodiversity, from the atomic to the molecular, from material to building blocks and products, as well as in sectors of applications and usage. Owing to their high diversity and adaptability, chemicals and synthetic materials are literally used everywhere nowadays.

Sound-scattering properties of Sierpinski triangle fractal structures in the near field

This paper proposes a new design of an acoustic diffuser based on the construction rules of the Sierpinski triangle in order to broaden the effective diffusion frequency range. The diffuser is made of triangular blocks of different sizes attached to a plane surface. The effects of the number of fractal iterations, the height of triangular blocks, and arrangements of the blocks on the normal-incidence diffusion coefficients in the near field are examined through numerical simulations based on the boundary element method (BEM) in the frequency range of 100 Hz – 5 kHz. Furthermore, measurement results will be presented to validate the diffusion performance presented by the numerical simulations. The diffusion performance of a conventional quadratic residue diffuser (QRD) is compared to confirm the advantage of the designed diffuser for broadening the effective frequency range. It shows that the fractal patterns with various sizes of blocks improve diffusion performance compared to the conventional QRD of the same size, especially in the mid-low frequency range below 1 kHz.