Geometric Elements Research Articles

Development of a specific software for the calculation of open channels with uniform flow considering energy principles

The purpose of this research project is the codification of a specific software for the calculation of open channels of uniform flow considering the energy principles, which allows to obtain quickly and safely the normal and critical tie, geometric elements, flow rate, optimal hydraulic section of the sections proposed by Ven Te Chow, rectangular, trapezoidal, triangular, circular, parabolic, rectangular with rounded corners and triangular with rounded bottom, in addition to the geometric elements for any equation of the parabola, the hydraulic headroom and weirs. To verify the veracity of the developed program "SN CANALES v2.0", the results obtained were checked with the existing HCANALES software and manually; obtaining a margin of error of less than 1.5%, thus verifying that the values obtained by the software are reliable.

Control of Propagation of Salt Wedge by using Roughness Blocks having Different Inclination

The hydraulic conditions of a flow previously proved to be changed when placing large-scale geometric roughness elements on the bed of an open channel. These elements impose more resistance to the flow. The geometry of the roughness elements, the numbers used, and the configuration are parameters that can affect the hydraulic flow characteristics. The target is to use inclined block elements to control the salt wedge propagation pointed in most estuaries to prevent its negative effects. The Computational Fluid Dynamics CFD Software was used to simulate the two-phase flow in an estuary model. In this model, the used block elements are 2 cm by 3 cm cross-sections with an inclined face in the flow direction, with a length of their sides 2 and 3 cm. These elements were placed with a constant spacing in two rows at a distance from two sides of the bed of the channel model. Six simulation runs were conducted with two different discharges and three different inclinations of the centerline of the element concerning the flow direction. The applied discharges are 30 and 45.3 l/min, and the inclination of roughness elements are 15o, 30o, and 45o. The spacing between elements in each row is kept at 3cm. The results showed that when no roughness elements were used, the propagation of the salt wedge extended to 3.9m and 3.1m at a discharge of 30 l/min and 45.31/min, respectively. The propagation of the salt wedge was reduced when using the inclined blocks roughness element. This reduction depends on the applied discharge and the angle of inclination. At the minimum applied discharge of 30 l/min, the propagation of the salt wedge was reduced by 74% at 45o inclination. In contrast, it was 69% at 30o and 64% at 15o inclination at the same discharge. When the discharge is 45.3 l/min, the propagation of the salt wedge was reduced by 85% at 45o inclinations of roughness, 84% at 30o. It was 70% at 15o inclinations. The roughness elements improve the flow turbulence that disperses and slows the salt wedge propagation beneath the fresh water.

Integrating generative parametric design workflow in the terraced concert hall design process

Compared to shoe box halls, terraced concert halls are popular due to their proximity to the stage and expressive design. However, its complex geometry requires delicate adjustments during the design process to effectively deliver a design that satisfies both the needs of acoustics and creativity. The study aims to explore the integration of generative parametric design workflow into the design of terraced concert halls and apply the workflow to an actual competition project. This workflow consists of three steps: defining basic parameters and reference geometries, generating and composing geometric elements with synchronized acoustic and geometric verification, and conducting performance evaluation of the results. The workflow enables integration of diverse viewpoints for the competition project, covering both the acoustics of the concert hall and the spatial integration with the surroundings. The outcome is a multi-layered, terraced concert hall with acoustic performance comparable to a traditional shoebox hall, and a metaphorical image of the topography of the city in which the concert hall is located.

Geometric Analysis of the Suggested Derlock Dam, DuhokReservoir using a Digital Elevation Model

Several application programs, including Global Mapper, Surfer and GIS, which deal with spatial analysis and extract spatial data and information for land features, were used to extract geometric elements of the proposed Derlock Dam reservoir based on the digital elevation model (DEM) with a discriminating ability of 10 m. It started at a level of 740 m at the site of the dam and reached a height of 900 m above sea level with an interval of 10 m. The relationship of the level with the negative volumetric and negative spatial elements showed that there is a large difference in the values of Negative Volume (NV), Negative Planar Area (NPA), and negative surface area (NSA) at the level of the reservoir (900 m), which is a positive factor in choosing the topograph Negative Surface Area depression, as it shows a significant decrease in the surface area (evaporation area) and the wet area (the area of penetration). This corresponds to a significant increase in the volume of the reservoirs, and indicates that the depression is deep and small in area, as well as the final economic feasibility of the project. It consists of two reservoirs, which will allow a strategy to maneuver the amount of water storage, as well as reduce the risks of flood waves and sediments that will be deposited behind the dam gate. The reservoir volume reached 900 m, 3611048537 billion m3, distributed among reservoirs near the dam with volumes of 445189305 million/m3 and 3166195232 billion/m3 for the reservoir far from the dam site, because the Upper Zab River does not have dams, so it will be able to build important reservoirs and control the river water during floods.‎

M-TAG: A modular teaching-aid for Geant4

Geant4 is a versatile Monte Carlo radiation transport simulation toolkit with a steep learning curve. This work introduces a user-code called M-TAG (Modular Radiation Teaching-Aid for Geant4), built on top of Geant4. M-TAG is designed to help gradually introduce the Geant4 toolkit to new users.The goal of Geant4 is to record quantities from the simulated radiation as it is transported through geometries. M-TAG simplifies the inclusion of new geometric elements and detector components in the simulation by including new classes. M-TAG also provides basic validated examples for some common detector development tasks. Geant4 intercom modules, called messenger classes, manage these classes. To validate M-TAG, simulations were performed to calculate the range of positrons in water. One hundred million decays at the center of a water-filled sphere with a radius of 1 m were allowed for fluorine-18, carbon-11, oxygen-15 and gallium-68. These results were compared to literature values. An inexperienced Geant4 user was tasked with creating a simulation model for a plastic scintillator-based detector and conducting basic tests to assess the effectiveness of M-TAG as a teaching tool. The simulation involved calculating the dose to the detector's sensitive volume using a 2x2 cm planar monoenergetic photon source spanning energies from 20 to 100 keV. One billion particles were simulated twice: once with the actual detector geometry and once with the sensitive volume replaced by water. The validity of M-TAG was also verified by computing dose ratios and comparing them with mass-attenuation ratios obtained from NIST XCOM data sets.The mean positron travel distances were within the distribution of literature values. Simulated positron energy spectra means were within 1.8% of literature means. Simulated dose ratios agreed with literature values within uncertainties.We have developed and verified a modular Geant4 teaching aid called M-TAG. It was used to introduce a new user to Geant4, who used it to perform further validation simulations.

PELAKSANAAN ANALISIS CP ELEMEN GEOMETRI UNTUK MERUMUSKAN TP, ATP, DAN MODUL AJAR PADA FASE E

Describe the dormulation of TP and ATP based on the CP geometric elements of Phase E and teaching modules tha show student-centered learnign is the goal of this research. A qualitative research approach was used in this research, collecting data in this research through documentation and interviewing Phase E mathematics teachers. The subject of this research is a matematics teacher Phase E. The data analysis technique used was the data from Miles Huberman which consisted of three activities namely data reduction, presentation, and conclusions. The results of this research show that the CP in Decree of the Head of BSKAP Number 33 of 2022 and the Content Standards for High School Mathematics subjects in Permendikbudristek Number 7 of 2022 are used by teachers to formulate TP, guided by the TP from the driving teacher. This research is focused on geometric elements in Phase E which contains trigonometry material. The CP element geometry is split into four TPs. The TP was compiled together with all math teachers at school to become ATP. Teachers collaborate to arrange material from easy to difficult. The ATP is then held at the MGMP forum to ensure effectiveness and suitability to learning needs. An open module design that can demonstrate student-focused learning is by using the Discovery Learning learning model. Then the teacher also uses discussion methods and peer tutoring.

Generative design of terraced concert hall – a case study of Taipei music and library centre

ABSTRACT The terraced concert hall offers a wide range of design options. Yet the knowledge barrier within a design team makes it difficult to effectively deliver a design that satisfies both the needs of creativity and acoustics. The study aims to explore the integration of generative parametric design collaboration workflow into the design of terraced concert halls and apply the cumulative results of the pilot study to the Taipei Music and Library Centre design competition. We propose an enhanced collaborating model between architects and acoustic consultants, integrating geometric design with acoustic verification in concert hall design. This cooperating model embraces and integrates three key steps: defining basic parameters and reference geometries, efficiently generating and composing geometric elements, and conducting geometric and acoustic statistical assessments. This design strategy enables integration of diverse viewpoints, covering both the acoustics within the hall and the space integration with the surroundings. The outcome is a terraced concert hall with an acoustic performance comparable to traditional shoebox-shaped halls.

A novel in silico Nuss procedure for pectus excavatum patients

The purpose of this study is to suggest a novel in silico Nuss procedure that can predict the results of chest wall deformity correction. Three-dimensional (3D) geometric and finite element model of the chest wall were built from the 15-year-old male adolescent patient’s computed tomography (CT) image with pectus excavatum of the mild deformity. A simulation of anterior translating the metal bar (T) and a simulation of maintaining equilibrium after 180-degree rotation (RE) were performed respectively. A RE simulation using the chest wall finite element model with intercostal muscles (REM) was also performed. Finally, the quantitative results of each in silico Nuss procedure were compared with those of postoperative patient. Furthermore, various mechanical indicators were compared between simulations. This confirmed that the REM simulation results were most similar to the actual patient’s results. Through two clinical indicators that can be compared with postoperative patient and mechanical indicators, the authors consider that the REM of silico Nuss procedure proposed in this study is best simulated the actual surgery.

The Interaction Principle in the Assessment of Pillars’ Secondary Stress-Deformation State

Abstract In the field of mining, one of the exploitation methods that is still the most used in rock salt, potassium, and magnesium salt deposits is the method with the room and abandoned pillar. The salt mining method with rooms and pillars represents a unique spatial system for which the establishment of an optimal correlation between the parameters of the room, pillar, and rock massif is required in any given situation. Thus, the dimensioning of the most requested element in the system is followed, and depending on its parameters, the other parameters of the system are established. Considering the exploitation method with rooms and pillars, the pillars are certainly the elements that are subjected to the greatest loads. In the situation where the deep exploitation of salt is done with square pillars, the evaluation of the optimal parameters of the elements of the exploitation system requires: establishing the loads that appear in the surrounding salt massif (the natural stress state); the qualitative-quantitative determination of the way of distribution of the secondary stress state in the pillars; evaluating the bearing capacity of the pillars; and establishing their geometric elements. Solving this problem can be achieved by different methods: based on the theory of limit equilibrium, taking into account the effective stress in the pillars; methods of the mechanics of the continuous system based on the analytical models for evaluating the secondary stress and deformation state of pillars and floors; and numerical methods combined with the results and measurements from the laboratory and in situ tests. A methodology based on the pillar–room–salt massif interaction principle was proposed for the analytically achievable stability exploitation system of rock salt by the dry method as the depth increased. Applying this method, the secondary stress-deformation state in the pillar can be established by taking into account the rheological behaviour of the salt, changing the pillar shape, and the extraction technology. The presented algorithm can be extended in the field of exploitation, where the room and pillar exploitation methods are used.

Negative Impact of Traffic Congestion on Air Pollution and Estimation Delay Mode for Signalized Intersections in Babil City Utilizing SIDRA8.0 Plus Software

Traffic congestion is one of the most important factors contributing to air pollution. Vehicle emissions account for a significant portion of this pollution. Estimate the negative impact of traffic congestion by empirical model for predicting total delay time as a function of traffic conditions and geometric features and calculating the quantities of gases emitted during the traffic congestion at the signalled intersection is the goal of this paper. Two signalized intersections in Babil City with different characteristics are select. video recording is used to measure traffic volumes during peak and off-peak times. Afield survey is used to measure geometric design elements, signal timings, phasing, and selected emissions of HC, CO, and CO2 in (kg/hr) are based on delay. with 95% confidence, a linear regression model predicted the delay model. according to the statistical analysis, both geometry and traffic characteristics have a substantial influence on delay time. The constructed regression model for estimating delay has a high degree of correlation with actual values. The proportion of the total width of the exit route of an intersection of straight-forward departing traffic to the total width of groups of lanes departing on the same exit route at the same phase at the stop line it is observed that although the SIDRA 8.0 PLUS delay overestimates the delay at the high (v/c) range, there is no noticeable difference with the field delay and the study will offer suggestions to transportation and public health officials on how to try eco-routing and deco-signal timing to lower the risk of air pollutants.

A geometrically nonlinear Cosserat shell model for orientable and non-orientable surfaces: Discretization with geometric finite elements

We investigate discretizations of a geometrically nonlinear elastic Cosserat shell with nonplanar reference configuration originally introduced by Bîrsan, Ghiba, Martin, and Neff in 2019. The shell model includes curvature terms up to order 5 in the shell thickness, which are crucial to reliably simulate high-curvature deformations such as near-folds or creases. The original model is generalized to shells that are not homeomorphic to a subset of R2. For this, we replace the originally planar parameter domain by an abstract two-dimensional manifold, and verify that the hyperelastic shell energy and three-dimensional reconstruction are invariant under changes of the local coordinate systems. This general approach allows to determine the elastic response for even non-orientable surfaces like the Möbius strip and the Klein bottle. We discretize the model with a geometric finite element method and, using that geometric finite elements are H1-conforming, prove that the discrete shell model has a solution. Numerical tests then show the general performance and versatility of the model and discretization method.

An isogeometric analysis framework for ventricular cardiac mechanics

The finite element method (FEM) is commonly used in computational cardiac simulations. For this method, a mesh is constructed to represent the geometry and, subsequently, to approximate the solution. To accurately capture curved geometrical features many elements may be required, possibly leading to unnecessarily large computation costs. Without loss of accuracy, a reduction in computation cost can be achieved by integrating geometry representation and solution approximation into a single framework using the isogeometric analysis (IGA) paradigm. In this study, we propose an IGA framework suitable for echocardiogram data of cardiac mechanics, where we show the advantageous properties of smooth splines through the development of a multi-patch anatomical model. A nonlinear cardiac model is discretized following the IGA paradigm, meaning that the spline geometry parametrization is directly used for the discretization of the physical fields. The IGA model is benchmarked with a state-of-the-art biomechanics model based on traditional FEM. For this benchmark, the hemodynamic response predicted by the high-fidelity FEM model is accurately captured by an IGA model with only 320 elements and 4700 degrees of freedom. The study is concluded by a brief anatomy-variation analysis, which illustrates the geometric flexibility of the framework. The IGA framework can be used as a first step toward an efficient workflow for an improved understanding of, and clinical decision support for, the treatment of cardiac diseases like heart rhythm disorders.

Large aperture and defect-free liquid crystal planar optics enabled by high-throughput pulsed polarization patterning.

The liquid crystal (LC) geometrical phase optics, which is realized by the high-resolution control of the optical axis orientation in transparent micrometer-thin polymer films, is emerging as a next generation of planar optics. It features pronounced optical properties and stimuli-responsive behaviors, which could introduce appealing and new possibilities for photonic purposes. The development of fabrication techniques producing elements with large aperture sizes and arbitrarily varying molecular orientation is of significance in terms of practical utility. Here, we propose the pulsed polarization patterning technique to create large-aperture and defect-free LC geometrical phase elements. We investigated the capability of the azo photo-alignment material responding to nanosecond laser pulses and the corresponding anchoring behaviors to LCs. The threshold was reduced to one fourth of that under the continuous wave recording. The patterning resolution was found to be enhanced to around 0.71 µm, due to the ultra-fast interaction nature of the photo-alignment material with the polarized light field. We proposed the flying exposure mode to deliver high frequency modulated polarized laser pulses (8 kHz), with the precision stage moving in a uniform velocity for light-field stitching and the servo auto-focusing in the sample normal, enabling the stable and reliable polarization patterning for large aperture sizes. We further report on representative fabrication of LC polarization gratings with an aperture of 4 inch and 99.2% average diffraction efficiency.

On the mechanical properties and vibrational characteristics of the nanoparticle-reinforced composite cylindrical panels in the acidic environment: Numerical and experimental investigation

The purpose of this study is to determine the impact of nano-clay and nano-silica particles on the vibrational characteristics of composite cylindrical panels in corrosive environments. In this context, due to the presence of diluted sulfuric acid as the corrosive solution, the coupling effects of material degradation and hygroscopic loading on the natural frequencies are taken into consideration. In order to achieve this, it is first explored through experiment how adding nanoparticles affects the coefficient of hygroscopic expansion of the glass/epoxy specimens. Using this coefficient, the in-plane loading caused by corrosive solution is then applied in the equations. The mechanical properties and hygroscopic expansion coefficients of the composite samples exposed to the corrosive environment are first determined by certain experimental testing. The equations of motion are derived using the first-order shear deformation theory (FSDT), and the vibration problem is solved using the generalized differential quadrature (GDQ) technique. Investigation is conducted into the effects of various nanoparticles, immersion time, geometrical elements, and boundary conditions on the natural frequencies of the cylindrical panels. It is found that adding nanoparticles can significantly improve the mechanical properties, the corrosion resistance, and the natural frequencies of composites in which the nano-clay is more effective. For example, adding nano-clay and nano-silica particles, respectively, results in 32.32% and 26.29% increase in elasticity modulus of reinforced glass/epoxy composite. In addition, 12.71% and 47.32% improvements are observed in the natural frequency of the nano-clay reinforced composite panel before and after 90 days of immersion in sulfuric acid. In comparison, the nano-silica particles are responsible for 7.80% and 23.03% increase in natural frequency before and after immersion time.

Development, calibration and validation of a comprehensive customizable lumbar spine FE model for simulating fusion constructs.

Instrumentation alters the biomechanics of the spine, and therefore prediction of all output quantities that have critical influence post-surgically is significant for engineering models to aid in clinical predictions. Geometrical morphological finite element models can bring down the development time and cost of custom intact and instrumented models and thus aids in the better inference of biomechanics of surgical instrumentation on patient-specific diseased spine segments. A comprehensive hexahedral morphological lumbosacral finite element model is developed in this work to predict the range of motions, disc pressures, and facet contact forces of the intact and instrumented spine. Facet contact forces are needed to predict the impact of fusion surgeries on adjacent facet contacts in bending, axial rotation, and extension motions. Extensive validation in major physiological loading regimes of the pure moment, pure compression, and combined loading is undertaken. In vitro, experimental corridor results from six different studies reported in the literature are compared and the generated model had statistically significant comparable values with these studies. Flexion, extension and bending moment rotation curves of all segments of the developed model were favourable and within two separately established experimental corridor windows as well as recent simulation results. Axial torque moment rotation curves were comparable to in vitro results for four out of five lumbar functional units. The facet contact force results also agreed with in vitro experimental results. The current model is also computationally efficient with respect to contemporary models since it uses significantly smaller number of elements without losing the accuracy in terms of response prediction. This model can further be used for predicting the impact of different instrumentation techniques on the lumbar vertebral column.

RUMAH EBANG SEBAGAI TEMPAT, SUMBER DAN MEDIA PEMBELAJARAN GEOMETRI SD DI LUAR KELAS BERBASIS ETNOMATEMATIKA

Mathematics learning can be carried out outside the classroom and the material can come from things that are close to students' daily lives. There needs to be a place, resources, and learning media to bridge students' cultural knowledge with mathematics material in schools. One of them is the student's knowledge of the Ebang house. This study aims to describe the Ebang house in Lembata and its potential as a place, source, and medium for learning elementary school geometry. This research is qualitative research. The research object is the Ebang house of the Kedang community on Lembata Island. The instrument used is data documentation in the form of pictures of traditional houses and interview data. The results of the study show that there are many geometric elements in the Ebang house. These geometric elements include plane shapes (triangles, quadrilaterals, polygons, trapezoids and circles) and spatial shapes (beams, pyramids, prisms, cubes, needles, and spheres. As a place and source of learning outside the classroom, students can observe directly the shapes geometric shapes contained in the Ebang house and its parts. In addition, the Ebang house can be a concrete medium to assist teachers in explaining geometric concepts to students. Planning for outdoor learning has the potential to make the Ebang house a good place for learning geometry because of the availability of materials and elementary school geometry learning media.

Enhanced Delamination Tolerance Levels by Hybridizing Carbon Laminates with Glass Plies: Parametric Study

Laminated composites are extensively used in the aerospace industry and one of the key issues is delamination tolerance in these configurations during the operational phase. This paper demonstrates that hybridization is an effective strategy to achieve higher delamination tolerance sizes. For the above purpose, this paper presents a method to hybridize two different practical laminated carbon composite panels with glass fibers and also a parametric study to evaluate the influence of various hybrid laminate parameters on the delamination tolerance. Geometrical non-linear finite element analysis is carried out on three-dimensional models of delaminated non-hybrid and hybrid composite laminates. The mode I Strain Energy Release Rate (SERR) is estimated using Modified Virtual Crack Closure Integral (MVCCI). The SERR components are compared for the hybrid and the non-hybrid laminates. It is demonstrated that an appropriate hybridization with glass plies in between a few top and bottom carbon layers enhances delamination tolerance levels without significantly affecting the stiffness of the laminate.

Ethnomathematics Exploration of The Great Mosque of Al-Barkah, Bekasi City, Through The Learning of Geometry and Transformational Geometry

Ethnomathematics is an understanding that makes culture a concrete form in constructing mathematical concepts. Ethnomathematics learning can help students improve their understanding of mathematical concepts and preserve Indonesian culture through an introduction to that culture. This research aims to investigate the symbolic meaning and ethnomathematics elements found in the Great Mosque of Al-Barkah. This research is qualitative research with a realist ethnographic approach. Data collection techniques were interviews, observation, documentation, and literature study. The study results prove that the Great Mosque of Al-Barkah has geometric elements (rhombuses and cuboids) and geometric transformations (reflections, rotations, and translations). Also, there are symbolic meanings in parts of the mosque. Thus, ethnomathematical elements were found in the mosque. The results of this discovery can be used as learning media and sample questions for learning mathematics at all levels of education (elementary, junior high school, and senior high school).

Ethnomathematics: Utilization and Introduction of Geometry Buildings Using Janur (Coconut Leaf)

One area of mathematics that requires a good understanding and depiction of abstract concepts is geometry. Therefore it is necessary to apply realistic learning. One type of realistic learning is ethnomathematics. Ethnomathematics is a bridge between mathematics and culture by linking culture and students' everyday experiences. Traditional crafts that can be lifted are creations from coconut leaves (janur) which can be formed into various kinds of craft creations that contain geometric shapes. The type of research used in this research is descriptive qualitative research. Data collection was used through literature and interviews. The results of the research show that creations from coconut leaves (janur) can be geometric shapes that can be used as ethnomathematics objects. These forms include (1) coins that can be made into hexagons, (2) kerises that have elements of equilateral triangles, right triangles, and parallelograms, (3) diamond bricks that have elements of square geometry lengths and blocks, (4) balls (balans) which have square and cube geometry elements, (5) sinta diamonds which have rhombus geometry elements and rhombus upright prisms. Other geometric elements contained in the janur creations are congruence, angles, and symmetry.
 Keywords: ethnomathematics, geometry, coconut leaves.

Generating Topologically Consistent BIM Models of Utility Tunnels from Point Clouds.

The development and utilization of urban underground space is an important way to solve the "great urban disease". As one of the most important types of urban underground foundations, utility tunnels have become increasingly popular in municipal construction. The investigation of utility tunnels is a general task and three-dimensional laser scanning technology has played a significant role in surveying and data acquisition. However, three-dimensional laser scanning technology suffers from noise and occlusion in narrow congested utility tunnel spaces, and the acquired point clouds are imperfect; hence, errors and redundancies are introduced in the extracted geometric elements. The topology of reconstructed BIM objects cannot be ensured. Therefore, in this study, a hierarchical segmentation method for point clouds and a topology reconstruction method for building information model (BIM) objects in utility tunnels are proposed. The point cloud is segmented into facades, planes, and pipelines hierarchically. An improved mean-shift algorithm is proposed to extract wall line features and a local symmetry-based medial axis extraction algorithm is proposed to extract pipelines from point clouds. A topology reconstruction method that searches for the neighbor information of wall and pipeline centerlines and establishes collinear, perpendicular, and intersecting situations is used to reconstruct a topologically consistent 3D model of a utility tunnel. An experiment on the Guangzhou's Nansha District dataset successfully reconstructed 24 BIM wall objects and 12 pipelines within the utility tunnel, verifying the efficiency of the method.