Planar Shape Research Articles

Numerical studies of the distribution capability of a continuous linear strain soil base model for largesized raft foundations

The paper examines the existing methodology for determining the main design parameters of the model in the form of a continuous linearly strained layer of finite distribution capability (the design thickness of the layer H0 and design stress-strain modulus E0) to simulate the adequate interaction between soil bases and large-size slab foundations. The aim of this work is to numerically study the stress-strain state of a uniformly loaded flexible rectangular foundation slab when the thickness of the soil base model layer is reduced in the form of a continuous linearly deformed layer of finite distribution capacity. Numerical studies of the effect of the thickness of the layer of the specified soil base model that interacts with a large-size flexible slab foundation of various rectangular shapes in plan were conducted in the SCAD package using the finite element method. The numerical study results have shown that when the ratio H0/Ha (the design thickness of the layer of the soil base model H0 to the actual compressible thickness of the soil base Ha) decreases, the maximum moment forces along the orthogonal axes of rectangular foundations decrease to 50% because of the decrease in the distribution capability of the soil base model and, accordingly, in the edge reactions R under the slab at equal average settlements of the slab saver. Numerical studies have shown interesting results on the distribution of moment forces in flexible rectangular slabs, where the maximum is outside the center of gravity of a uniformly loaded raft, which confirms the peculiarity of the interaction of flexible slabs with relatively narrow compressible layers under the sole. With an appropriate in-situ experimental justification, the use of the soil base model in the form as a continuous linearly strained layer of finite distribution capability with the design parameters (H0 and E0) rather than with the actual parameters (Ha and Ea) in calculations of large-size slab foundations can be of fundamental practical importance in their rational design, as the reinforcement can be reduced to 50%

Hydrocarbon microseepages in the kerkennah islands, Eastern Tunisia: Integrated surface geochemical and geoelectrical prospecting approaches

Oil exploration is usually carried out using conventional techniques such as seismic reflection and exploratory drilling. However, these techniques are very costly with a high risk of dry holes or failure to find commercial quantities of hydrocarbons. Here we aim to evaluate surface geochemical prospection (SPG) methods which serve as preliminary step to derisk an area by exploring hydrocarbon micro-seeps. This approach helps to identify potential areas of interest when you have limited amount of money to explore a given area. This paper reports on surface gas micro-seepages in the Kerkennah archipelago, part of the Tunisian Pelagian Platform. 33 gas and soil samples were collected on a 1 × 1 km grid over Chergui Island. Both free gas and adsorbed soil gas techniques were used. Free hydrocarbon gas concentrations ranged from 0 to 21 ppm. Adsorbed gases showed concentrations up to 11 ppm. The presence of all light hydrocarbon gas components from methane to pentane, the values of the gas ratios C1/C2, C1/ΣC2+, (C3/C1) x 1000 and C1/(C2 + C3), and the Pixler and triangular diagrams together indicate that these gases are of thermogenic origin and have migrated from subsurface accumulations. Anomalous concentrations of hydrocarbon gases occurred in the middle and west of the study area. Both free and adsorbed gas anomalies have the same planar shape and form linear anomalies with a NW-SE trend. This orientation corresponds to that of the major fault system affecting the Kerkennah archipelago. Subsequent independent VES surveys and re-interpreted seismic lines confirmed the presence of a surface fault as suggested by the surface gas anomalies. In conclusion, our study has confirmed the presence of thermogenic hydrocarbon gas microseepage to the surface. The gases are interpreted to have migrated to the surface along faults. SPG methods were thus able to identify active hydrocarbon migration and can be considered as a useful low-cost approach to hydrocarbon exploration.

New Parametric 2D Curves for Modeling Prostate Shape in Magnetic Resonance Images

Geometric shape models often help to extract specific contours in digital images (the segmentation process) with major precision. Motivated by this idea, we introduce two models for the representation of prostate shape in the axial plane of magnetic resonance images. In more detail, the models are two parametric closed curves of the plane. The analytic study of the models includes the geometric role of the parameters describing the curves, symmetries, invariants, special cases, elliptic Fourier descriptors, conditions for simple curves and area of the enclosed surfaces. The models were validated for prostate shapes by fitting the curves to prostate contours delineated by a radiologist and measuring the errors with the mean distance, the Hausdorff distance and the Dice similarity coefficient. Validation was also conducted by comparing our models with the deformed superellipse model used in literature. Our models are equivalent in fitting metrics to the deformed superellipse model; however, they have the advantage of a more straightforward formulation and they depend on fewer parameters, implying a reduced computational time for the fitting process. Due to the validation, our models may be applied for developing innovative and performing segmentation methods or improving existing ones.

Towards realistic structural char models: Generation of stacked graphene-like layers using constrained reactive molecular dynamics simulations

For a molecular understanding of coal combustion, realistic coal and char models are pivotal. We propose a novel top-down method for the construction of char models, consisting of stacked graphene-like layers with defects. We start on the mesoscale with corrugated stacked surfaces as a template. Then the carbon atoms are pre-positioned on these surfaces and surrounded by hydrogen atoms. In a constrained reactive MD simulation the carbon atoms are then rearranged into a chemically reasonable state with dangling bonds saturated by hydrogen atoms. Importantly, the initial shape of the template is maintained to a great extent, leading to a substantial amount of defects in the graphitic planes, especially for high curvatures. In a final step, small molecular fragments and unfavorable arrangements are removed and remaining dangling bonds are saturated with hydrogen atoms. The central advantage over other approaches is the ability to choose the shape and size of the templating planes, with the possibility to use experimental input.The method is validated on single sheets with a protrusion and application examples are shown for stacked graphitic layers with up to 100 Å size and more than 20000 atoms. It represents the first step of a longer term project. In the future, heteroatoms and functional groups will be implemented, and by combining several such stacks, the approach will allow the construction of more realistic char models using the data from HRTEM images as an experimental boundary condition. On this basis important questions like the adsorption and diffusion of volatiles under high temperatures can be studied on a molecular level.

Thematic Teaching Materials of Connected Type Sultan Mahmud Badaruddin I Palembang Mosque Materials Mathematics for Class II Elementary School

Connected type teaching materials are part of thematic learning which can be used as an alternative in facilitating mathematics learning. The material chosen is math material in grade II elementary school including multiplication, division, and simple plane shapes. The theme used in this study is the Great Mosque of Sultan Mahmud Badaruddin I Palembang which is well known to students. This research is a development research using the stages of development of Tessmer and Akker. The two major stages of this development research are: (1) Introduction, and (2) Formative Evaluation. Data collection with walkthroughs, documentation and tests. Data analysis was in the form of product analysis of teaching materials by looking at the results of tracing and documentation of the one to one stage, expert reviews and small groups, and analysis of test data obtained from the field test stage. Based on the results of product analysis, valid and practical teaching materials were obtained. Validity can be seen from the results of the assessment of content/content experts (according to the thematic approach of the connected type), construct experts (according to the characteristics of teaching materials), and language experts (according to PEUBI). Practically seen from the results of students' assessments in small group trials where students stated that the teaching materials provided were easy to understand. The potential effect is seen from the evaluation test results. The teaching materials compiled were declared valid after going through the one to one stage, expert review which had been revised according to expert advice. Practically illustrated from the results of small groups that have gone through the revision stage. The potential effect of this study is 86.1 and is included in the very good category.

DFT Atomic‐Scale Insight into Pt/Cu Single Atom Alloy Clusters Supported on γ‐Al2O3: The Effect of Hydrogen Environment

Single atom alloy (SAA) clusters formed by anchoring single atoms in small supported host clusters are emerging as catalysts with high performance. In this work, density functional theory (DFT) calculations and ab‐initio molecular dynamics (AIMD) simulations are performed to study the stability and the structure evolution of γ‐alumina‐supported platinum/copper SAA clusters of sub‐nanometer size in hydrogen environment. Due to the strong dynamic nature of both Cu cluster and anchored Pt single atom and their evolving interaction with the support, different isomers with different geometric and energetic properties are predicted. Extensive sampling through AIMD simulations reveals strong effect of hydrogen on the location of Pt single atom and strong variation of the cluster shape, evolving from 3D to concave and planar shapes wetting the alumina support. Interfacial site location of Pt single atom is found to be hydrogen coverage dependent. When the hydrogen coverage increases, the Pt single atom located preferentially at the interfacial site is pulled up by hydrogen atoms toward the upper surface Cu layers. The interaction of Pt/Cu cluster with alumina is predicted to decrease with increasing hydrogen coverage. Finally, electronic structure analysis reveals dramatic effect of hydrogen on the metallic nature of the catalysts.

PENGARUH MEDIA SMART BOOK TERHADAP KEMAMPUAN PEMECAHAN MASALAH MATEMATIKA

This study aims to determine the effect of smart book media on elementary school’s mathematics problem solving abilities, with the subject of plane shapes which focusing on the cognitive abilities. This study method uses is an experimental (pre-experimental) from a quantitative approach with a design one group pretest-posttest design. The sampling technique in this research is non-probability sampling, which is saturated sampling with a sample used 21 students. The research was carried out at SDN Sindanghurip located in Salawu. The instrument used is a written test in the form of an essay questions test.. Furthermore, the results of the t-test calculation obtained t_count = 11.51 and t_table = 2.08596, because the value of t_count = 11.51 outside the acceptance area of ​​​​ H₀, so H₀ is rejected and H₁ is accepted. Therefore, it can be concluded that the use of smart book media of can affect the mathematical problem solving abilities of elementary on subject of plane shapes that focus on student’s cognitive abilities, precisely on fifth grade students at SDN Sindanghurip.

Design and research of a new multi-loop closed-chain morphing wing mechanism

Innovative design and investigation into multi-configurable morphing wing mechanism (MWM) have been focused on meeting the evolving needs of morphing aircraft with extensive spatial and velocity domains. In this paper, a design methodology for multi-loop closed-chain mechanism (MLCCM) involved the substitution of Bennett mechanism links with sub-mechanisms, and an innovative design of 4-RSPCR MLCCM is proposed based on the method, incorporating equivalent spherical mechanism and group theory. Subsequently, a multi-module morphing wing mechanical network consisting of the 4-RSPCR MLCCM is proposed, and the degrees of freedom (DOF) for the multi-module MWM is analyzed using graph theory. In addition, kinematic models for single module mechanism are established, and research on kinematic modeling methods for multi-module mechanisms is conducted. Finally, a prototype of a six-module MWM is constructed, and deformation experiments is conducted. The results show that the proposed innovative mechanisms and the novel multi-module morphing wing mechanical network facilitate the serialized design for various wing planar shapes. Furthermore, these mechanisms enable multi-configurational deformations, including bi-directional bending and variable span. These findings lay the groundwork for fundamental research and engineering applications of morphing wings in morphing aircraft.

Buildings of Distinct Plan Shapes Under Wind Load: Wind Interference Effects

Buildings of Distinct Plan Shapes Under Wind Load: Wind Interference Effects

Peningkatan Hasil Belajar Matematika melalui Penerapan Model Pembelajaran Accelerated Learning Tipe Message (Mindset, Entrance, Switch-Ownership, Store, Act, Go-again, Engage) pada Peserta Didik Kelas 5 SDN Dukuh Kupang V Surabaya

This research aims to improve mathematics learning outcomes in flat volume material through the application of the MESSAGE Type Accelerated Learning learning model (Mindset, Entrance, Switch-Ownership, Store, Act, Go-again, Engage) in grade 5 students at SDN Dukuh Kupang V Surabaya . The method used in this research is Classroom Action Research (PTK) which is carried out in two cycles, each consisting of planning, implementation, observation and reflection. The research results showed a significant increase in students' mathematics learning outcomes. In the pre-cycle, the percentage of student learning completion only reached 55%. After implementing the MESSAGE learning model in cycle I, the percentage of student learning completion increased to 70%. In cycle II, the percentage of student learning completeness further increased to 85%. This increase shows that the application of the MESSAGE Type Accelerated Learning learning model is effective in improving mathematics learning outcomes regarding volume of plane shapes in class 5 students. Based on the results of this research, it is concluded that the use of the MESSAGE learning model can increase student involvement and facilitate better understanding of concepts, thus having a positive impact on their mathematics learning outcomes. It is recommended for educators to consider using this model as an alternative in teaching mathematics.

Engineering of asymmetric A1-D1-A2-D2-A1 type non-fullerene acceptors of 4T2CSi–4F derivatives to enhance photovoltaic properties: A DFT study

Designing efficient, non-fused ring-based organic solar cells (OSCs) with high open circuit voltage is a significant challenge. The present research proposes seven novel moieties generated from an existing 4T2CSi–4F (R) asymmetric molecule to increase efficiency. The density functional theory (DFT) was used to examine several essential characteristics like optical, electronic, and efficiency-related properties of molecules. It is revealed that newly presented molecules have superior features that are required to manufacture efficient organic solar cells. They exhibit a lower band gap between 2.05 and 2.34 eV and have a planar shape. Six moieties exhibit lower excitation energy values in the gas and chloroform phases, and five moieties have more excellent dipole moments than the R molecule. UA1 and UA2 show remarkable enhancement in the optoelectronic properties, exhibiting the greater λmax at 773 nm and a smaller excitation energy of 1.60 eV. All the newly presented molecules have lower ionization potential and reorganization energies of the electron. The open circuit voltage (Voc) of five newly designed molecules is greater, varying from 1.40 to 1.55 eV, than R (Voc = 1.38 eV). Furthermore, the newly designed molecules, except UA1 and UA2, show more excellent fill factor (FF) than the R molecule. This significant increase in efficiency-associated metrics (FF and Voc) suggests that these molecules may be effectively implemented to manufacture an upgraded version of OSCs.

Topology optimization of broadband acoustic transition section: a comparison between deterministic and stochastic approaches

This paper focuses on the topology optimization of a broadband acoustic transition section that connects two cylindrical waveguides with different radii. The primary objective is to design a transition section that maximizes the transmission of a planar acoustic wave while ensuring that the transmitted wave exhibits a planar shape. Helmholtz equation is used to model linear wave propagation in the device. We utilize the finite element method to solve the state equation on a structured mesh of square elements. Subsequently, a material distribution topology optimization problem is formulated to optimize the distribution of sound-hard material in the transition section. We employ two different gradient-based approaches to solve the optimization problem: namely, a deterministic approach using the method of moving asymptotes (MMA), and a stochastic approach utilizing both stochastic gradient (SG) and continuous stochastic gradient (CSG) methods. A comparative analysis is provided among these methodologies concerning the design feasibility and the transmission performance of the optimized designs, and the computational efficiency. The outcomes highlight the effectiveness of stochastic techniques in achieving enhanced broadband acoustic performance with reduced computational demands and improved design practicality. The insights from this investigation demonstrate the potential of stochastic approaches in acoustic applications, especially when broadband acoustic performance is desired.

강원지역 입보용 산악산성의 현황과 특징

‘Mountain’ means ‘high, rugged mountains.’ This mountainous terrain is one of the geographical features of the Gangwon region, and fortresses are located here and there in the mountains. In this paper, I would like to summarize the contents of fortresses in mountainous areas for entry among the mountain fortress data accumulated to date in the Gangwon region and briefly look at their characteristics. The fortress to be discussed in this paper will be examined with a focus on ruins for which archaeological investigation has been conducted at least once. The ruins are seven fortresses, including Gwongeumsanseong in Sokcho, Hangyesanseong in Inje, Dootasanseong in Donghae, Samaksanseong in Chuncheon, Yeongwonsanseong in Wonju, and JeongyangsanseongㆍTaehwasanseong in Yeongwol. The common characteristics of these fortresses are that they built walls using the rugged natural terrain (mountains) and used natural cliffs as walls to defend against invasion from the outside. The fortress wall surrounds the valley, making it easy to secure a water source, and is built in layers. Since the natural surface was used, the planar shape of the fortresses is not constant (irregular). In addition, the area of the mountain fortress is wide to maximize the living space inside, creating conditions for long-term staging. In addition, most of the mountain fortresses have historical facts related to the Khitan, Mongolia, etc., so they have something in common that shows national patriotism. Most of the artifacts excavated through archaeological investigations also correspond to this period. There is a study that shows that there is a lack of planning in the construction of mountain fortresses for entry in the Gangwon region. However, looking at the common characteristics of the fortresses mentioned above, it appears that there was sufficient planning. In addition, due to the rugged terrain, it is believed that it was only managed by the town police station in normal times, but when war broke out, it took on that role. From literature and archaeological investigations, it is believed that most mountain fortresses in the Gangwon region were built for the purpose of staging a sit-in. It can be said that the fortresses were built during the Goryeo Dynasty and operated until the Joseon Dynasty. However, the outer castle of Jeongyangsanseong in Yeongwol is different in that it was built with walls in addition to the inner wall built during the Three Kingdoms period and was operated until the Joseon Dynasty, but the characteristics of castles in other mountainous terrains in the Gangwon region are similar. For mountain fortresses in Korea, the English expressions “castle” and “fortress” are often used. In preparing this article, I believe that the large fortress wall located on the rugged mountainous terrain during the Goryeo Dynasty also had the meaning of “a shelter”.

Predicting the ultimate bearing capacity of spudcan in stiff-over-soft clay based on a failure model varying with soil parameter

A jack-up platform is prone to a ‘punch-through’ accident when working on the stiff-over-soft clay foundation. To assess the risk of punch-through, it is necessary to plot the bearing capacity-penetration curve for evaluating the penetration depth of the pile leg or to calculate the ultimate bearing capacity of the spudcan and compare it with the preload. However, accurate prediction of spudcan bearing capacity is not easy. In this paper, the failure mode about the stiff-over-soft clay under different geological conditions when punch-through occurs is discussed using coupled Eulerian lagrangian (CEL) method, varying the strength ratio between soft and stiff soil layers, the thickness of stiff soil relative to the spudcan diameter, and the non-homogeneity factor of soil strength. Based on the soil failure model with varying soil parameters, a new calculation method for ultimate bearing capacity of spudcan is proposed and then verified against existing centrifuge test results. The results show that the shape of soil shear plane in stiff clay is significantly affected by the strength ratio of soil layer and the non-homogeneity factor of soil strength. And the presented new method whose prediction errors compared with centrifuge test results are less than 5%, has better calculation accuracy than the ISO (International Organization for Standardization) method, which is valuable in guiding the calculation of the ultimate bearing capacity of the spudcan and ensuring the safe operation of the jack-up drilling units on stiff-over-soft clay.

Spectroscopic Characterization of Highly Excited Neutral Chromium Tricarbonyl.

Spectroscopic characterization of highly excited neutral transition-metal complexes is important for understanding the multifaceted reaction mechanisms between metals and ligands. In this work, the reactions of neutral chromium atoms with carbon monoxide were probed by size-specific infrared spectroscopy. Interestingly, Cr(CO)3 was found to have an unprecedented 7A2″ septet excited state rather than the singlet ground state. A combination of experiment and theory shows that the gas-phase formation of this highly excited Cr(CO)3 is facile both thermodynamically and kinetically. Electronic structure and bonding analyses indicate that the valence electrons of Cr atoms in the septet Cr(CO)3 are in a relatively stable configuration, which facilitate the highly excited structure and the planar geometric shape (D3h symmetry). The observed septet Cr(CO)3 affords a paradigm for exploring the structure, properties, and formation mechanism of a large variety of excited neutral compounds.

Biomimicking trilayer scaffolds with controlled estradiol release for uterine tissue regeneration.

Scaffold-based tissue engineering provides an efficient approach for repairing uterine tissue defects and restoring fertility. In the current study, a novel trilayer tissue engineering scaffold with high similarity to the uterine tissue in structure was designed and fabricated via 4D printing, electrospinning and 3D bioprinting for uterine regeneration. Highly stretchable poly(l-lactide-co-trimethylene carbonate) (PLLA-co-TMC, "PTMC" in short)/thermoplastic polyurethane (TPU) polymer blend scaffolds were firstly made via 4D printing. To improve the biocompatibility, porous poly(lactic acid-co-glycolic acid) (PLGA)/gelatin methacryloyl (GelMA) fibers incorporated with polydopamine (PDA) particles were produced on PTMC/TPU scaffolds via electrospinning. Importantly, estradiol (E2) was encapsulated in PDA particles. The bilayer scaffolds thus produced could provide controlled and sustained release of E2. Subsequently, bone marrow derived mesenchymal stem cells (BMSCs) were mixed with gelatin methacryloyl (GelMA)-based inks and the formulated bioinks were used to fabricate a cell-laden hydrogel layer on the bilayer scaffolds via 3D bioprinting, forming ultimately biomimicking trilayer scaffolds for uterine tissue regeneration. The trilayer tissue engineering scaffolds thus formed exhibited a shape morphing ability by transforming from the planar shape to tubular structures when immersed in the culture medium at 37°C. The trilayer tissue engineering scaffolds under development would provide new insights for uterine tissue regeneration.

Scattered Acoustic Field Above a Rigid Rectangular Cuboid Shape in a Rigid Plane

A model is presented for the scattered acoustic field above a bulky rigid cuboid shape in a rigid plane insonified by an acoustic field. The Kobayashi Potential method and the image sources method were used in order to derive the scattered acoustic field in a modal form. The incident source was then decomposed into plane waves. The total scattered field was determined by summing all the elementary scattered fields. This model was compared to finite element modeling and experimental results for three bulky cuboid shapes in an infinite rigid screen and a rectangular corner insonified by a spherical source. A good agreement between numerical and experimental results was obtained supporting the validity of the model.

Submerged flow over various shapes of piano key weir

The weir, an essential element of dams utilized for floodwater management, plays a crucial role in human life. Over the years, nonlinear weirs have advanced into Piano Key Weirs (PKWs). These PKWs provide enhanced discharge efficiency, a reduced structural footprint, and heightened cost-effectiveness. PKWs possess a sophisticated structure defined by numerous geometric parameters. The impact of these parameters on the discharge capacity is of paramount significance. This study aims to experimentally investigate the hydraulic of submerged PKWs with different plan shapes, including triangular, trapezoidal, and rectangular, with apex width to cycle width ratio of (A/w) of 0, 0.25, and 0.5, and magnification ratio (B/w) of 1, 2, and 3, respectively. The results indicate that submergence depends on the shape and size of the PKW. Furthermore, the efficiency of the PKW increases as the ratio of approach flow head to weir height (Ho⁄P) decreases and B⁄w increases. The influence of the shape of the PKW on the performance of the weir is more pronounced at higher values of B/w. Additionally, the order of the highest discharge coefficient values follows a pattern from the trapezoidal to triangular and rectangular PKWs. Specifically, for B⁄w = 2, the trapezoidal PKW exhibits an approximate improvement of 6 and 15 % in the discharge efficiency compared to the triangular and rectangular PKWs, respectively. A new equation was developed to predict the discharge coefficient for different shapes of PKWs under various hydraulic conditions. Based on the experimental data, this study offers valuable insights into the hydraulic behavior and discharge coefficient of PKWs. This research significantly contributes to enhancing our understanding and optimizing the performance of submerged PKWs in water management systems.

Fundamental Limits on Earth-like Exoplanet Imaging with Large Telescopes Employing Laser Tomographic Adaptive Optics Systems: A Comparative Analysis of LGS AO and LTAO Systems

Exoplanet imaging with high-contrast imaging adaptive optics systems, though challenging, is a promising path toward the characterization of terrestrial planets. We analyzed the fundamental limitations associated with the direct imaging of terrestrial exoplanets around low-mass stars with Extremely Large Telescopes using laser tomographic adaptive optics (LTAO) and derived the post-coronagraph image shape in the focal plane from LTAO systems. Additionally, the fundamental limitation of direct imaging was found to come from unseen spatial frequencies during tomographic reconstruction. Through the provision of optimization strategies for laser guide star (LGS) asterisms, based on the post-coronagraph image contrast, we aimed to assist in the design of LTAO systems for Extremely Large Telescopes, resulting in a six-fold improvement in the LTAO post-coronagraph image plane at 0.1 arcseconds.

Optimal wall shapes and flows for steady planar convection

We compute steady planar incompressible flows and wall shapes that maximize the rate of heat transfer ( $Nu$ ) between hot and cold walls, for a given rate of viscous dissipation by the flow ( $Pe^2$ ), with no-slip boundary conditions at the walls. In the case of no flow, we show theoretically that the optimal walls are flat and horizontal, at the minimum separation distance. We use a decoupled approximation to show that flat walls remain optimal up to a critical non-zero flow magnitude. Beyond this value, our computed optimal flows and wall shapes converge to a set of forms that are invariant except for a $Pe^{-1/3}$ scaling of horizontal lengths. The corresponding rate of heat transfer $Nu \sim Pe^{2/3}$ . We show that these scalings result from flows at the interface between the diffusion-dominated and convection-dominated regimes. We also show that the separation distance of the walls remains at its minimum value at large $Pe$ .