Circle Shape Research Articles

An Energy-Adjustable, Deformable, and Packable Wireless Charging Fiber Supercapacitor.

Wireless charging energy storage devices eliminate bulky wires of wearable electronics. However, rigid shape and specific charging energy restrict their applications in space-limited portable electronics. Herein, an all-carbon fiber supercapacitor is presented that features shape-adjustable, packable, and energy-controllable wireless charging functions. With the unique on-dimensional circuit structure, the maximum energy transfer efficiency from the electrical energy received by the wireless charging unit to the output energy of the fiber supercapacitor can reach up to ≈60.8%, and meanwhile this integrated fiber device exhibits an outstanding area capacity of 803 mF cm-2 and energy density of 1004 µWh cm-2, superior to most of the fiber supercapacitors. Moreover, this unique device can endure significant deformation in shape of circles ranging from 2 to 20cm diameter, and can be packed into narrow spaces, such as smart bracelet and disk-shaped pet global positioning system (GPS). By altering the device shape, the wireless charging current, voltage, and power can be adjusted in the range of 0.5-20mA, 1.4-15.5V, and 0.003-313mW, accommodating the energy requirements for nearly all existing micro-electronics. This work offers unprecedented opportunities for packable, space-confined and energy harvesting controllable wearable electronics.

Microstructure of ternary Sn-Bi-xCu alloy on mechanical properties, current endurance and corrosion morphology via cycling corrosion test

Low melting temperature of Sn-58 wt.% Bi (SB) solders adding 0.5wt.% Cu (SB05C) and 1.7wt.% Cu (SB17C) concentrations were evaluated for the signal transmission in the 3D IC package. Microstructure combined with phase analysis and Pandat simulation were together with to explain the relationship among the mechanical property, electrical endurance and corrosion resistance. By Cu decoration, the presence Cu6Sn5 intermetallic compound (IMC) acts as heterogeneous nucleation sites to reduce surface free energy and generate fine Bi grain that resulted in higher hardness value. The power-law was used to explain the mechanism of interfacial IMC growth, both Cu6Sn5 and Cu3Sn formation were speculated to be volume diffusion control and surface reaction domination, respectively. The fracture morphology by shear testing indicates that earliest plastic deformation accompanied with brittle rupture were major factors due to the intergranular fracture and Cu6Sn5 compound induced bulk fracture. By cycling corrosion test (CCT), the lump shape of SnO2 by-product was found among solders at three cycling. After seven cycling, Sn phase has been completely corroded and Cu6Sn5 IMC began to be corroded forming circle shape of Cu2O but Bi phase still not be corroded among solders. In the electrical endurance, dense Cu6Sn5 dispersed in solder bulk and fine grain size were feasible to induce current crowding and joule heating, thus Cu deteriorated SB solders is easily failed.

Population receptive field models capture the event-related magnetoencephalography response with millisecond resolution

Abstract Much of the visual system is organized into visual field maps. In humans, this organization can be studied non-invasively by estimating the receptive fields of populations of neurons (population receptive fields; pRFs) with functional magnetic resonance imaging (fMRI). However, fMRI cannot capture the temporal dynamics of visual processing that operate on a millisecond scale. Magnetoencephalography (MEG) does provide this temporal resolution but generally lacks the required spatial resolution. Here, we introduce a forward modeling approach that combines fMRI and MEG, enabling us to estimate pRFs with millisecond resolution. Using fMRI, we estimated the participant’s pRFs using conventional pRF-modeling. We then combined the pRF models with a forward model that transforms the cortical responses to the MEG sensors. This enabled us to predict event-related field responses measured with MEG while the participants viewed brief (100 ms) contrast-defined bar and circle shapes. We computed the goodness of fit between the predicted and measured MEG responses across time using cross-validated variance explained. We found that the fMRI-estimated pRFs explained up to 91% of the variance in individual MEG sensor’s responses. The variance explained varied over time and peaked between 75 ms to 250 ms after stimulus onset. Perturbing the pRF positions decreased the explained variance, suggesting that the pRFs were driving the MEG responses. In conclusion, pRF models can predict event-related MEG responses, enabling routine investigation of the spatiotemporal dynamics of human pRFs with millisecond resolution.

Magnetic and mechanical analyses of superconducting coil for the magnetic Czochralsky technique

Solar cells, electronics, and the semiconductor industry all need high-quality silicon crystals. The Czochralsky technique has been widely used to make a high-quality single silicon crystal from the silicon melt. However, this technique needs a strong magnetic field to stabilize the melt and control the temperature. In this paper, two coils with a curved shape have been optimized and simulated to produce a transverse magnetic field for the Czochralsky technique grower. The coils face each other and have an opening angle of 150°, and a NbTi superconducting wire was used to wind the coils with 5110 turns. The current was 106 A and flowing in the same direction. The finding results indicated that the magnetic field at the silicon melt center is 0.4 T, and the peak field in coils is 2.95 T. The optimized curve shape coils were compared with conventional coils (circle shape coils). The comparison indicated that the curve shape coils produced a highly uniform magnetic field, required less current, and significantly reduced the outer diameter of the superconducting magnet. In addition, heat generation by the current leads was calculated. In the case of the curve-shaped coils, less heat leakage has been achieved; as a result, the cooling capacity, magnet size, weight, and cost will be reduced. Furthermore, mechanical analysis was performed, and the results showed that the stress in the coils is within the permissible range for NbTi at 4.2 K.

On the effect of patterned hole on the thermal conductivity of Ψ-graphene nanosheet: A molecular dynamics simulation

Molecular Dynamics (MD) simulation is used here to evaluate Thermal Conductivity (TC) of perfect and defective ψ-graphene. The defect is applied in the shape of circle, square, diamond, and triangle shapes on the nanosheets. Moreover, vacancy defect is also applied to the nanosheet. The influence of the defect on the TC of the ψ-graphene is investigated. It is shown that TC of the defective ψ-graphene is lower than the perfect one. Besides, to investigate the effect of temperature on the TC of the ψ-graphene, the temperature is changed in the range of 200–700 K. It is shown that the TC is inversely depends on the temperature. However, increasing the temperature leads to increase in the TC of the considered structure.

Investigation of preference for local and global processing of Capuchin-monkeys (Sapajus spp.) in shape discrimination of mosaic arrangements.

Classical experiments using hierarchical stimuli to investigate the ability of capuchin monkeys to integrate visual information based on global or local clues reported findings suggesting a behavioral preference for local information of the image. Many experiments using mosaics have been conducted with capuchin monkeys to identify some of their perceptual phenotypes. As the identification of an image in a mosaic demands the integration of elements that share some visual features, we evaluated the discrimination of shapes presented in solid and mosaic stimuli in capuchin monkeys. Shape discrimination performance was tested in 2 male adult capuchin monkeys in an experimental chamber with a touchscreen video monitor, in three experiments: (i) evaluation of global and local processing using hierarchical stimuli; (ii) evaluation of target detection using simple discrimination procedures; (iii) evaluation of shape discrimination using simple discrimination and delayed matching-to-sample procedures. We observed that both monkeys had preferences for local processing when tested by hierarchical stimuli. Additionally, detection performance for solid and mosaic targets was highly significant, but for shape discrimination tasks we found significant performance when using solid figures, non-significant performance when using circle and square shapes in mosaic stimuli, and significant performance when using Letter X and Number 8 shapes in mosaic stimuli. Our results are suggestive that the monkeys respond to local contrast and partly to global contrast in mosaic stimuli.

Exploring Ethnomathematics on The Batik Patterns of Jember In Mathematics Concept

This study aims to identify and describe mathematical concepts and describe the results of ethnomathematics exploration contained in Jember batik motifs. The type of research used in this study is qualitative research with an ethnographic approach. The research instruments used were observation, tests, and interviews with batik artisans. The results of this study indicate that the combination of coffee bean and tobacco leaf motifs has applied mathematical concepts of geometry. In the motif of coffee beans and tobacco leaves from the Nhora Pangetu hand-written batik production house, there are mathematical concepts of curves, points, circles, and the concept of dilation. The motif of coffee beans and tobacco leaves from the Gangsar Ngaidin batik production house contains mathematical concepts of reflection (mirroring), congruence, and flat shapes of circles, triangles, and rhombuses.

Collapse Behavior and Energy Absorption Characteristics of Design Multi-Cell Thin Wall Structure 3D-Printed Under Quasi Statistic Loads

Crashworthiness is a passive device that has an important function as an absorbing component of the impact energy resulting from an accidental event. The main problem in the crashworthy design is the dimensional limitation on the front end of the vehicle with the driver so that most of the energy absorption is limited. Besides, the complexity of crashworthiness design is difficult to make conventionally. This research aims to find out the effectiveness of crashworthiness design in energy absorption and the resulting deformation patterns. Crashwortines are made in a multi-cell shape using PLA material and printed using a 3D printing raise machine. Crashworthiness is produced with four variation shapes of a Multi-cell circle (MCC), Multi-Cell square (MCS), Multicell pentagonal (MCP), and Multi-Cell pentagonal circles (MCPC) with a side thickness of 2 mm and a length of 150 mm. Experimental quasi-static testing is carried out in the frontal direction using a UTM machine at an operating speed of 2mm/s. The results of the study show that the design of the crash box of the pentagon circle has a significant increase in the energy absorption value of 62.49%, which can be recommended in future impact resistance tube designs. The characteristics of the deformation pattern and the failure resulting from the crashworthiness tend to form the pattern of the bending lamina failure. Failures can occur due to plastic fold, elastic bend, and pressure deformation mechanisms followed by new folding formations (lobes).

Domain shape evolution under multiple IR laser irradiation in lithium niobate

In this work, we have studied the shape evolution of the isolated domains in domain array in congruent lithium niobate crystals under the action of pyroelectric fields arising during multiple irradiation by laser pulses. The loss of the circle shape with the pulse number was obtained in the arrays of isolated domains arising at the edges of the irradiated zone. The simulation of the domain growth under the action of the pyroelectric field allowed revealing two stages of domain shape evolution in the regular domain array. An important role of the neighboring domains was revealed.

Mechanical behaviors of a new elliptical valve stent in bicuspid aortic valve

Background and ObjectiveThe conventional valve stents that are cylindrical in shape will become elliptical when implanted in bicuspid aortic valve, thereby reducing the durability of the artificial valve. In this study, a new design of valve stent is presented where valve stents have elliptical cross-section at the annulus and it is expected to have better expandability and circle shape during the interaction between the stent and bicuspid aortic valve, thereby extending the durability of artificial valve. MethodsFinite element method (FEM) is used to study the mechanical behavior of the novel valve stent in the bicuspid aortic valve. The effects of three matching relationship between the ellipticity of the stents and the ellipticity of the annulus (i.e., the ellipticity of the stent is greater than, equal to and less than the annulus ellipticity, respectively) on the mechanical behavior of stent expansion are studied. In addition, the expansion mechanical behavior of the novel valve stent at different implantation depths is also compared. ResultsResults indicate that novel valve stent implantation with elliptical features is superior to conventional circular valve stent. When the novel valve stent ellipticity is less than the annulus ellipticity, the ellipticity of the novel valve stent after implantation is smaller than that of the conventional circular valve stent. This indicated that the novel valve stent has better expandability and post-expansion shape, making artificial valve to have better durability. The risk of paravalvular leak after implantation is lowest when the novel valve stent ellipticity is less than annulus ellipticity. When the novel valve stent ellipticity coincides with annulus ellipticity, the aortic wall is subjected to greatest stress. With the increase of implantation depth, the stress on the novel valve stent decrease. ConclusionsThis study might provide insights for improving stent design for bicuspid aortic valve.

Phytochemical profile, anti-inflammatory analysis and cytotoxic activity of SmE-SeNPs against breast (MCF-7) cancer cells

Plant extract is inexpensive and does not need special conditions to produce nanoparticles quickly; it is an eco-friendly approach. Selenium nanoparticles have attracted a lot of attention because of their various applications and benefits in medicine. This investigation studied a bio-synthesis of selenium nanoparticles using Sonchus maritimus leaves aqueous extract (SmE-SeNPs) to evaluate their anti-inflammatory and anti-cancer properties. The presence of SmE-SeNPs in the sample was confirmed by ultraviolet–visible (UV–vis) spectroscopy at different stage of synthesis, and transmission electron microscope. The S. maritimus extract was analyzed by LC-ESI-MS technique. The anti-inflammatory proprieties of the extract and SmE-SeNPs was estimated using protein denaturation and membrane stabilization assays, and the antiproliferative activity of the synthesized nanoparticles was assessed against breast cancer cell line (MCF-7). LC-ESI-MS results revealed the richness of S. maritimus extract by various phenolic compounds including protocachuic acid, trans frulic acid, o-coumaric acid and luteolin. Physical characterizations of nanoparticle demonstrated that the SeNPs have a spherical and regular circle shape with very small size reach to 7.154 ± 0.47 nm. Both of S. maritimus extract and SmE-SeNPs presented a potential anti-inflammatory activities compared to standard, each against denaturation of protein with IC50 value (334.369 ± 29 μg/mL) and (163.393 ± 14.1 μg/mL) respectively, or against the hemolysis of red blood cells through protecting and stabilizing their membrane with IC50 value (89.044 ± 4.11 μg/mL) for SmE-SeNPs and (53.539 ± 4.64 μg/mL) for S. maritimus extract. Moreover, this study showed that exposure of SmE-SeNPs can inhibited MCF-7 cell proliferation, which observed in breast cancer. As conclusion, our research suggested that Sonchus maritimus leaves aqueous extract can be used as reducer and stabilizer agents for green synthesis of SmE-SeNPs which provided their anti-inflammatory and anticancer effects.

Smart System on Two-dimensional Shapes Recognition Application for Kindergarten Students

Abstract. Kindergarten-aged children are going through an important period of cognitive development, such as the ability to think concretely, including recognizing simple geometric shapes such as circles, triangles, and squares. However, many children find it difficult to understand the basic concepts of two-dimensional shapes.Purpose: It is necessary to develop prototype learning aids in the form of intelligent systems in two-dimensional shapes applications for kindergarten students, which utilize information technology and object visualization directly through cameras on smartphones. This is expected to increase children's learning motivation and help strengthen their understanding of two-dimensional shapes.Methods: The research combines Waterfall and Agile methodologies, tailoring them to four stages: plan and discovery, analysis and design, application development, and testing. Testing gathers accuracy with 120 smartphone-collected data points for square, triangle, circle, and pentagon shapes. Also, usability testing based on learnability, efficiency, memorability, error handling, and satisfaction, was obtained from six kindergarten teacher questionnaires and quantitatively processed.Results: The application achieves an accuracy rate of approximately 79%. Notably, accuracy decreases with fewer corners, mainly due to low resolution or lack of focus, resulting in simplified detected shapes. Regarding usability, it is evident that the application has received positive feedback from users, particularly kindergarten teachers, who have given it an average score of 78.83.Novelty: Distinguished from previous research, the novelty of this study resides in its ability to capture objects through a camera, eliminating the need for predefined shapes within the application, and innovating by creating an educational tool aligned with the kindergarten curriculum to recognize two-dimensional shapes. The research contribution is the creation of an innovative learning tool for kindergarteners, merging smartphone technology with real-world objects to teach two-dimensional shapes, thus integrating technology into early childhood education effectively, which has urgency in efforts to improve the quality of learning.

Fluid flow and mixing in a channel with dual bluff bodies

Placing bluff bodies in a mixing channel is an important technique to enhance mixing. This paper numerically investigates the effects of transversal spacing and axial spacing of two bluff bodies on the outlet mixing efficiency (Mout), the pressure loss (ΔP), and the combined performance parameter η (the ratio of Mout to dimensionless ΔP) of fluid flow within mixing channels with dual bluff bodies having three cross-sectional shapes of circle, square, and sector with Reynolds numbers based on bluff body dimension Red = 20, 60, and 100. The study reveals that, at Red = 20, altering the spacing between the two bluff bodies in the mixing channel does not improve mixing but instead increases ΔP, leading to a decrease in η. At Red = 60 and 100, changing the transversal spacing and axial spacing in a certain range can effectively enhance mixing and improve the combined performance. There exists an optimal transversal spacing to maximize Mout and η. Furthermore, the mixing channel with sector-shaped dual bluff bodies exhibits the highest Mout and η among the three kinds of cross-sectional shapes. When Red = 60 and 100, η of the mixing channel with sector-shaped dual bluff bodies increases by 212% and 270% by the transversal offsetting compared to the case with zero transversal spacing and increases by 489% and 331% by the axial offsetting compared to the case with an axial spacing of 2 times the bluff body dimension. The present findings hold significant implications for the design optimization and performance improvement of mixers.

Karakterisasi dan Potensi Ekstrak Daun Paitan (Tithonia diversifolia) sebagai Penolak Nyamuk Aedes aegypti

The paitan plant (Tithonia diversifolia) contains alkaloids, saponins, flavonoids, tannins and phenolics which have the potential to prevent Dengue Hemorrhagic Fever (DHF). This plant also has various insecticidal activities. In society, there are many mentions of the paitan plant, so people need to know the characteristics of this paitan plant. The aim of this research is to determine the morphological characterization and specific fragments of the paitan plant, as well as to determine the activity and effective concentration of the ethanol extract of paitan leaves as a repellent for the Aedes aegypti mosquito. Two types of methods were used, namely descriptive qualitative for observing morphology, specific fragments, pollen, and phytochemical screening, and experimental methods for mosquito repellent testing, and calculating the protective power of the ethanol extract of paitan leaves. The results obtained are flowers consisting of two shapes, namely ribbon flowers in the outer circle, infertile, and tube shapes in the inner circle. Stomata are anomocytic type, while trichomes are non-glandular multicellular type. Pollen characteristics, namely small size, colpate, number 3, aperture shaped trizonocolpate with echinate ornamentation. The screening results for the ethanol extract of paitan leaves were positive for containing metabolite compounds, such as flavonoids, alkaloids, tannins, saponins, terpenoids and phenolics. The results of the mosquito repellent test showed that the higher the concentration of the extract, the fewer mosquitoes that landed. Calculation of protective power shows that the most effective concentration in repelling mosquitoes is 15%, namely 93.64%. The conclusion is that paitan (Tithonia diversifolia) leaf extract has potential activity as a repellent against Aedes aegypti mosquitoes with the most effective concentration being 15%.

Engineering Drawing of Cirebon Gunungan Puppet Shape through Ethnomathematics

Cirebon Gunungan Puppet is one of the gunungan puppet figures that has shape characteristics in the Java region. Gunungan puppet is a puppet figure whose presence is considered important in every puppet show. Therefore, these puppet figures are often reproduced to meet the needs of puppet show. However, knowledge of the gunungan puppet preparation is still limited to traditional knowledge that is less understandable by today's younger generation who need more objective and systematic knowledge. Therefore, this study aims to compose knowledge of gunungan puppet with a focus on composing engineering drawings in the Cirebon gunungan puppet shape through ethnomathematics. The method used in this study is qualitative with an experimental approach. The theory used to support the achievement of this gunungan puppet engineering drawing is ethnomathematics. The composition of the Cirebon gunungan puppet engineering drawings produced three stages, that are the base grid system that determined through ethnomathematical ratio, the contour base that resulting from the arrangement of triangle, circle, and square shape, and the outline shape that resulting from drawing the outline from the geometric shape arrangement to create the Cirebon gunungan puppet shape. The results of this research are expected to be a reference for learning traditional art and design objectively and systematically, especially in the creation of Cirebon mountain puppets.

Curvature-based interface restoration algorithm using phase-field equations

In this study, we propose a restoration algorithm for distorted objects using a curvature-driven flow. First, we capture the convex-hull shaped contour of the distorted object using the mean curvature flow. With the supplemented mass on the captured feature, we evolve the constraint mean curvature flow to a steady state, preserving the non-distorted region. With respect to the mass, we select a restorative shape by considering the square of the curvature derivative. The Allen–Cahn and Cahn–Hilliard equations are applied to the generated restored image from the implicit curvature motions represented by the order parameter. We impose the Dirichlet boundary condition for the order parameter and the Neumann boundary for the chemical potential to fix the feature and to inherit the mass conservation, respectively. We provided examples of the restoration of half-circle and parentheses-shaped objects to reconstruct a circle shape.

Biohydrogen improvement from reactive honeycomb wood based on inert heat recirculating

Hydrogen production from biomass is an efficient and clean utilization way for renewable energy to significantly alleviate the energy crisis. In order to improve the biomass conversion efficiency, a device combining honeycomb structure wood and inert porous pellets was proposed, and the combustion characteristics of honeycomb wood was studied with different biomass species and pore structures. The results indicated that softwood had the higher syngas yield compared with hardwood, and the hydrogen yield was up to 9.0 %. The increasing of inlet air velocity improved combustion temperature, but it was not conducive to syngas production. In addition, circle shape structure showed the stable combustion rate and the high conversion efficiency due to the uniform pore distribution. With the increasing of pore number, outlet temperature and hydrogen production increased first and then decreased. Moreover, syngas yield improved as the pore diameter increased and the maximum hydrogen growth rate reached 256 %. Meanwhile, the co-combustion mechanism of honeycomb wood and inert pellets was revealed, and the efficient realization of heat-hydrogen coproduction had practical guiding significance for optimizing the energy structure.

Chiral organic molecular structures supported by planar surfaces.

We employ the molecular dynamics simulations to study the dynamics of acetanilide (ACN) molecules placed on a flat surface of planar multilayer hexagonal boron nitride. We demonstrate that the ACN molecules, known to be achiral in the three-dimensional space, become chiral after being placed on the substrate. Homochirality of the ACN molecules leads to stable secondary structures stabilized by hydrogen bonds between peptide groups of the molecules. By employing molecular dynamics simulations, we reveal that the structure of the resulting hydrogen-bond chains depends on the isomeric composition of the molecules. If all molecules are homochiral (i.e., with only one isomer being present), they form secondary structures (chains of hydrogen bonds in the shapes of arcs, circles, and spirals). If the molecules at the substrate form a racemic mixture, then no regular secondary structures appear, and only curvilinear chains of hydrogen bonds of random shapes emerge. A hydrogen-bond chain can form a zigzag array only if it has an alternation of isomers. Such chains can create two-dimensional (2D) regular lattices or 2D crystals. The melting scenarios of such 2D crystals depend on density of its coverage of the substrate. At 25% coverage, melting occurs continuously in the temperature interval 295-365K. For a complete coverage, melting occurs at 415-470 K due to a shift of 11% of all molecules into the second layer of the substrate.

Development of high-strength lightweight concrete by utilizing food waste digestate based biochar aggregate

The application of carbon-negative biochar in cement composites can effectively reduce carbon emissions of construction materials. In this study, low-carbon composites were tailored with high volume of food waste digestate (FWD) biochar aggregate. The biochar was customized at different temperatures with the goal of enhancing the properties of cement-based composites. Backscattered electron microscopy (BSEM) images show that FWD biochar with a grey circle shape exhibited strong bonding with the cement matrix. Nano-indentation results indicate that the two statuses of FWD biochar showed visco-elastic and elastic-plastic modes of deformation, respectively. The FWD biochar aggregate prepared at higher pyrolysis temperatures (i.e., 650 °C and 750 °C) has higher elastic modulus (up to 11.4 GPa), which can be applied to make biochar blocks with higher strength and lower density compared to the biochar pyrolyzed at 550 °C. As a result, FWD 750BC blocks could reach 28-d compressive strength of 57.8 MPa and density of 1.77 g cm−3, which fulfilled the requirements of high-strength lightweight aggregate concrete. Hence, this study established a foundation to utilize FWD biochar as an aggregate in high-strength biochar construction materials.

Optimizing Generative Adversarial Network (GAN) Models for Non-Pneumatic Tire Design

Pneumatic tires are used in diverse industries. However, their design is difficult, as it relies on the knowledge of experienced designers. In this paper, we generate images of non-pneumatic tire designs with patterns based on shapes and lines for different generative adversarial network (GAN) models and test the performance of the models. Using OpenCV, 2000 training images were generated, corresponding to spoke, curve, triangle, and honeycomb non-pneumatic tires. The images created for training were used after removing highly similar images by applying mean squared error (MSE) and structural similarity index (SSIM). To identify the best model for generating patterns of regularly shaped non-pneumatic tires, GAN, deep convolutional generative adversarial network (DCGAN), StarGAN v2, StyleGAN v2-ADA, and ProjectedGAN were compared and analyzed. In the qualitative evaluation, the GAN, DCGAN, StarGAN v2, and StyleGAN v2-ADA models distorted the circle shape and did not maintain a consistent pattern, but ProjectedGAN retained consistency in the circle, and the pattern was less distorted than in the other GAN models. When evaluating quantitative metrics, ProjectedGAN performed the best among several techniques when the difference between the generated and actual image distributions was measured.