Shape Of Cylinder Research Articles

A New Yield Surface for Cemented Paste Backfill Based on the Modified Structured Cam-Clay

Cemented paste backfill (CPB) is a cemented void filling method gaining popularity over traditional hydraulic or rockfill methods. As mining depth increases, CPB-filled stopes are subjected to higher confining pressures. Due to the soil triaxial apparatus limitations, as the conventional method of triaxial testing on CPB, no confining pressures higher than 5 MPa can be applied to CPB over a range of curing time. This lack of data introduces uncertainty in predicting CPB behavior, potentially leading to an overestimation of the required strength. To address this, this study introduces a new testing method that allows for higher confinement beyond traditional limitations by modifying the Hoek triaxial cell to accommodate low-strength materials. This study then investigates the coupled influence of confining pressure and curing time (hydration) on CPB characteristics, specifically examining the impacts of different curing times and confining pressures on the mechanical and rheological properties of CPB. A total of 75 triaxial tests were conducted using 42 mm cylinder shape samples at five various curing times from 7 to 96 days, and applied at low and high confinement condition levels (0.5 to 30 MPa). The results reveal that hydration and confinement positively impact the CPB strength. The modified structured Cam-Clay model was selected to predict the behavior, and its yield surface was updated using the experimental results. The proposed yield model can be utilized to describe CPB material subjected to various curing and pressure conditions underground.

Analyzing thermal performance and entropy generation in time-dependent buoyancy flow of water-based over rotating sphere with ternary nanoparticle shape factor

Abstract The heat transfer augmentation, solar power systems, medical equipment, semiconductor cooling, aerospace, and automotive industries all use ternary hybrid nanofluids (Thnf). The current study is mainly about a magnetized Thnf flow that can't be squished around a spinning sphere that has different viscosity, thermal conductivity, and shape (brick, platelets, cylinder, blade). The heat transport simulation incorporates the principles of viscous dissipation and joule heating. Water is mixed with silver, magnesium oxide, and iron trioxide to make the ternary hybrid nanofluid. Similarity substitution converts model equations to ordinary differential equations (ODEs). Runge-Kutta fourth order numerically estimates the non-dimensional set of ODEs. For certain emergent parameters, velocity, temperature, entropy generation, Nusselt number, and skin friction are computed and analyzed. The research shows that entropy generation increases with brinkman number, nanoparticle volume fraction and magnetic parameters and reduces with temperature difference parameter. Increasing the unsteadiness parameter upsurges velocity in the x-direction, but decreases it in the z-direction and temperature curve. Skin friction upsurges in the x-direction and declines in the z-direction with rotation. Platelet-shaped nanoparticles usually outperform blade, brick, and cylinder shapes. When mass suction $( S )$ is elevated from 1.0 to 2.0, the heat transfer rate increases by 47.25% for the Brick form, 47.26% for the Platelets shape, 35.08% for the Cylinders shape, and 37.65% for the Blades shape. Comparing the results to prior literature shows excellent agreement.

Microparticle sorting in microfluidic Taylor–Couette flows

In this experimental study, we demonstrate that settling polymethyl methacrylate (PMMA) microparticles with diameters ranging from 6 to 60 µm segregate into distinct bands according to their size when subjected to a rotating laminar annular gap flow with a diverging gap width in the axial direction. Different gap widths ranging from 130 to 1200 µm have been investigated in the fully laminar flow regime. Distinct, spatially separated particle bands of different particle sizes have been observed for nine different geometric configurations, including non-conical, conical, double conical, and variously inclined conical inner cylinder shapes. The study considers different rotation rates, geometric combinations, particle volume fractions, and particle size combinations. Particle size separation was achieved at volume fractions ranging from 2.2% to 11% for rotating inner cylinders. In contrast, no separation occurs during the experimental run when both the outer and inner cylinders are perfectly cylindrical, with no significant variation in the annular gap height. Our experiments also show that rotation of the inner cylinder results in more pronounced particle separation than rotation of the outer cylinder. Microscopic particle image velocimetry (µPIV) measurements show that the presence of particles induces an axial velocity component, which acts as a key transport mechanism. In addition, a significant variation in shear rate is observed across particle bands, which may explain size segregation by shear-induced migration. Furthermore, single particle simulations show that particle trajectories and velocities vary significantly with particle size.

Application of Numerical Integration in Analysing the Volume of Reinforcement Particles in Algorithms for Generating Representative Volume Elements (RVEs)

Abstract The paper focuses on spatial modelling of composites with discontinuous reinforcement. The algorithm for creating a representative volume element (RVE) must consider random distribution and size of reinforcing particles (RP), prevention of RP interpenetration, and maintaining the desired volume fraction of the reinforcing phase (Vp) in the composite microstructure. Assuming fixed RVE dimensions and randomly determined RP size, the actual Vp value needs to be continuously determined. If the assumed (desired) Vp is lower than the current value, additional reinforcement is added to the RVE. As the RP location is random, some particles may extend beyond the RVE limits, affecting Vp calculation. The research aims to determine the RP volume within the RVE boundaries when RP extends outside. The RVE was discretized with N points, and the number of Ni points within the area occupied by RP was determined. The sought value was calculated using the ratio Ni /N = Vp /VRVE, where VRVE, is the volume of the RVE. Two discretisation methods, systematised (RI) and random (Monte Carlo (MC)), were employed. The study investigated the effects of discretisation type and number N points on calculation accuracy and microstructure generation time for particle-reinforced composites in sphere, cylinder, and ellipsoid shapes. Systematised discretisation yielded higher accuracy/stability, with number N dependent on RP dimensions. The MC method reduced generation time but introduced instability and significant errors.

Effect of prefabricated auxiliary devices in different optical properties and shapes on the accuracy of intraoral scanning of the edentulous arch with multiple implants: An in-vitro study

ObjectivesThis study aimed to evaluate the impact of prefabricated auxiliary devices (PADs) in different optical properties and shapes on the accuracy of digital implant impressions. MethodsAn edentulous maxillary all-on-4 master model was fabricated. PADs were 3D-printed in different resin materials (Grey, Translucent, White, Yellow) and shapes (Cuboid, Cylinder, Sphere) using a 3D printer (AccuFab-C1s, 3DShining, Hangzhou, China). The master model was digitalized using a dental laboratory scanner (D2000, 3Shape, Copenhagen, Denmark) 4 times as the reference models. Test models were obtained without (control group) or with PADs by an intraoral scanner (Aoralscan 3, Shining3D, Hangzhou, China) for ten repetitions of each group using the scanning pattern recommended by the manufacturer. The related files were imported into inspection software to assess Root Mean Square (RMS), linear and angular accuracy. Aligned Ranks Transformation ANOVA, Kruskal-Wallis and Mann-Whitney tests were used to evaluate the differences in these values. The level of significance was set at α=0.05. ResultsPADs in different optical properties and shapes demonstrated accuracy enhancement to different extents depending on their combinations. The PADs in combinations of white-cuboid, grey-sphere and yellow-sphere demonstrated the optimal trueness enhancement. The Aligned Ranks Transformation ANOVA indicated that the optical properties of the PADs significantly influenced the RMS, linear and angular accuracy. The main effect of optical properties indicated that translucent PADs generally generated more deviations than the others. The shapes of the PADs significantly influenced the angular accuracy. The main effect of shapes indicated that cylinder resulted in lower angular trueness on YZ plane than cuboid (p = 0.006) and sphere (p < 0.001). ConclusionThe optical properties and shapes of the PADs significantly influenced the scanning accuracy. Translucent PADs demonstrated more deviations than the others. Lower angular trueness on the YZ plane was seen in cylinder design compared to the others. Clinical significanceThe optical properties and shapes of prefabricated auxiliary devices should be critically considered to optimize the scanning accuracy. Prefabricated auxiliary devices in translucent optical properties and cylinder shape should be avoided.

Analysis of the slump test for on-site yield stress measurement of thickened tailings

Yield stress of thickened tailings is a basic parameter in the design of tailings pipeline transport and discharge systems. To accurately determine the yield stress of thickened tailings, it is essential to develop a rapid determination method suitable for engineering applications and explore the relationship among various factors. In this paper, a high-precision velocity-controlled slump test system was designed to investigate the effects of thickened tailings temperature, lifting speed, slump cylinder shape, and tailings slurry mass concentration on the slump value. The test results indicate that the slump value decreases with the increases in thickened tailings temperature, resulting in a higher yield stress. Lifting speed significantly affects the yield stress, a faster lifting speed produces a larger slump value, which in turn leads to a smaller calculated yield stress. The lifting speed of 0.01 m/s provides a yield stress calculation that is close to the actual value. Moreover, among the tested slump cylinder shapes, the results obtained from the cylinder with dimensions of 100 mm (height) × 100 mm (diameter) are the closest to the actual values. These findings offer technical support for rapid and accurate on-site testing of the rheological parameters of thickened tailings and provide theoretical support for developing disposal methods for tailings.

Smart analysis of sandwich foldable cylinders as gymnastic accessories

A novel smart analysis of sandwich composite cylindrical shell is presented in this article. It is assumed that the sandwich shell is manufactured from the graphene origami reinforced copper core between two intelligent layers. The proposed structure in this article can be used as an idealized model for cylinder shapes in gymnastic sport and physical therapy units. The virtual work principle in the piezo elasticity framework and the cylindrical coordinate system is extended to derive governing equations. To arrive at more accurate results, a third order shear deformable model is extended for kinematic relations. The electro elastic responses are explored using the analytical method to seek impact of main parameters of the composite structure such as foldability parameter, graphene content percent, and applied electric potential on the electro elastic strain, deformation and stress results.

Validity of the quasi-2D optimal variable density lattice for effective liquid cooling based on Darcy–Forchheimer theory

In this study, we investigate the validity of variable-lattice-density optimization based on the Darcy–Forchheimer theory for an effective liquid-cooling quasi-2D structure including experimental verification. The unit lattice features a simple cylinder shape, and its size distribution is optimized. Considering its anisotropy, we regard Darcy’s permeability, Forchheimer’s drag coefficient, and the effective thermal conductivity as tensors and calculate these effective properties using the representative-volume-element method. Two types of optimizations are performed, i.e., minimizing the surface temperature and maximizing the flow rate, using the gradient method. We examine the results using three methods: an approximate simulation based on the Brinkman–Forchheimer equation, a detailed simulation based on the Navier–Stokes equation, and an experiment. We focus primarily on the exact measurement of planar temperature distribution using thermocouples. The proposed methodology exhibits high accuracy in regions with a certain flow level, although the error can be significant in low-flow regions.

Flow dynamics and heat transfer characteristics of flows past a zigzag cylinder in a bounded domain

A comprehensive numerical and experimental study is conducted to investigate the flow dynamics and heat transfer characteristics of flows past a novel wavy-axis circular cylinder placed symmetrically between two parallel walls. For comparison, the flow past a corresponding straight-axis cylinder within the same bounded domain is also studied. The investigations were primarily conducted at Reynolds numbers of 626 and 680, based on the average velocity and diameter of the cylinder, with a blockage ratio of 0.42, based on the widest area of the channel. At these flow conditions, the straight cylinder expectedly showed a “reverse” von Kármán type wake. However, the special zigzag cylinder showed fundamentally distinct flow patterns at the wake leading to a significant drag reduction and a heat transfer enhancement, compared to the performance of the straight cylinder. The pressure drop of the zigzag cylinder is 14 % and 19.4 % lower than that of the straight cylinder, with a higher convective heat transfer coefficient of 24 % and 9 %, respectively, for Reynolds numbers of 626 and 680. The substantial drag reduction is attributed to the formation of steady flow pattern in the wake indicating the suppression of unsteady vortex shedding. The heat transfer enhancement was mainly caused by the formation of elongated vortical structures principally aligned in the streamwise direction. The creation of these streamwise vortex tubes tends to more efficiently mix the fluid between the near-wall area and the core region of the channel than the near-planar vortex shedding associated to the straight cylinder. It was shown that the 3D shape of the zigzag cylinder generates a spanwise velocity component, which results in the creation of a dominant streamwise vorticity component that eventually develops into sustained vortex tubes.

Two orientation effects and large anisotropy of parameters in piezo-active 2–1–2 composites based on [0 1 1]-poled crystals

The results of a comparative study on piezo-active 2–1–2 composites with two ferroelectric components are discussed. The composite structure combines elements of 2–2 (laminar) and 1–3 (fibrous) connectivity patterns. The first component in each composite is domain-engineered [0 1 1]-poled single crystal with macroscopic mm2 symmetry and high piezoelectric activity. The second component is a poled ferroelectric ceramic that is represented by parallel rods in the shape of an elliptic cylinder with a large ratio of semi-axes at its base. The first orientation effect is appreciable due to rotations of the main crystallographic axes X and Y around Z || OX 3 by an angle α in each crystal layer. Rotation of the ceramic rod bases by an angle γ in a polymer medium leads to the second orientation effect in the 2–1–2 composite. The two orientation effects contribute to a large anisotropy of electromechanical coupling factors k3j∗ , energy-harvesting figures of merit (FOM) (Q3j∗)2 and modified FOM F3j∗σ for a stress-driven harvester. The large level of (Q32∗)2 , (Q33∗)2 , F32∗σ and F33∗σ (these parameters are of the order of 10−11–10−10 Pa−1) indicates that the studied composites are suitable for piezoelectric sensors, transducers and energy-harvesting systems. New m—α diagrams put forward in the present study show regions wherein the large anisotropy of the effective parameters ( |k33∗ / k3f∗|⩾5 , (Q33∗/Q3f∗ )2 ⩾10 and F33∗σ/F3f∗σ⩾10 , f = 1 and 2) is achieved when changing the volume fraction m of the single crystal and the rotation angle α. As a result, the leading role of the first orientation effect is emphasised.

Determination of vat-photopolymerization parameters for microneedles fabrication and characterization of HPMC/PVP K90 dissolving microneedles utilizing 3D-printed mold

Three-dimensional (3D) printing serves as an alternative method for fabricating microneedle (MN) patches with a high object resolution. In this investigation, four distinct needle shapes: pyramid mounted over a long cube (shape A), cone mounted over a cylinder (shape B), pyramidal shape (shape C), and conical shape (shape D) were designed using computer-aided design (CAD) software with compensated bases of 350, 450 and 550 µm. Polylactic acid (PLA) biophotopolymer resin from eSun and stereolithography (SLA) 3D printer from Anycubic technology were used to print MN patches. The 3D-printed MN patches were employed to construct MN molds, and those molds were used to produce hydroxypropyl methylcellulose (HPMC) and polyvinyl pyrrolidone (PVP) K90 dissolving microneedles (DMNs). Various printing parameters, such as curing time, printing angle, and anti-aliasing (AA), were varied to evaluate suitable printing conditions for each shape. Furthermore, physical appearance, mechanical property, and skin insertion ability of HPMC/PVP K90 DMNs were examined. The results showed that for shape A and C, the suitable curing time and printing angle were 1.5 s and 30° while for shapes B and D, they were 2.0 s and 45°, respectively. All four shapes required AA to eliminate their stair-stepped edges. Additionally, it was demonstrated that all twelve designs of 3D-printed MN patches could be employed for fabricating MN molds. HPMC/PVP K90 DMNs with the needles of shape A and B exhibited better physicochemical properties compared to those of shape C and D. Particularly, both sample 9 and 10 displayed sharp needle without bent tips, coupled with minimal height reduction (< 10%) and a high percentage of blue dots (approximately 100%). As a result, 3D printing can be utilized to custom construct 3D-printed MN patches for producing MN molds, and HPMC/PVP K90 DMNs manufactured by those molds showed excellent physicochemical properties.

A comprehensive study of carbon nanoparticle shape and orientation effects on composite elastic properties using FEA

In this study, three critical parameters that influence the effective composite properties of Carbon nanoparticles were tested and modeled using finite elements through Digimat Finite Element Analysis (FEA) software, employing representative volume elements (RVE). The primary parameters under consideration are the fiber shape, fiber orientation, and fiber volume fraction. Four of the many different shapes of Carbon nanoparticles, namely Tubes, Disk, Sphere, and Cylinder, were investigated, coupled with four distinct orientations for tubes: horizontal, aligned at 45°, random, and vertical each varying in the carbon fiber volume fraction. The material of choice was pure epoxy resin because of the nature of the bonding between its two phases and its wide range of usage. Forces were applied along the X-axis, coupled with shear in the XY plane. This study revealed that the orientation of CNTs primarily influences the Elastic Young’s modulus, whereas the size of the CNTs has the main effect on the shear modulus, followed by orientation. The horizontal CNTs demonstrated superior Young’s modulus, but the random orientation had a more pronounced impact on the shear modulus variation. Regarding the analysis of the nanoparticles shapes, the disk shape with fixed orientation revealed the highest elastic modulus, after which the cylinder shape and the sphere recorded the minimum elastic modulus among the three studied shapes.

Heat flow density measurement during non-destructive testing

The object of the study is the development of a device capable of accurately and reliably measuring heat flux density in various environments. The development of a heat flux density meter designed for non-destructive analysis of thermal processes in various fields of application is presented. The developed device is intended for evaluating the thermal insulation condition of underground pipelines. The functionality of the heat flow device relies on comparing standard temperature values with experimental ones measured on the soil surface. To ensure accurate and reliable measurement of heat flux density, the basis is a thermoelectric battery converter, which uses the auxiliary wall method. The heat flow density measuring device is constructed in the shape of a restricted cylinder, with one base serving as the working surface, while the second base establishes thermal contact with the body at ambient temperature. Embedded heaters enable the generation of heat flow through the thermoelectric sensor in directions perpendicular to its base. For calibrating the heat flux device, experiments were conducted using a standard copper-constantan calibration table. Temperature increments were determined from thermo electromotive force, and tests were performed on an existing heating network. The conducted measurements validate the fundamental feasibility of employing the proposed device for implementing the non-destructive thermal testing method on underground heating mains. The results of the experiment can be used not only for research, but also for monitoring and regulating processes in various fields of science and technology. The developed heat flux meter promises a significant contribution to the development of modern methods for analyzing thermal processes. The dimensions of the thermoelectric battery converter are also determined and the coefficient (kq) should be in the range from 4.0 to 12.0 W/(m2⋅mV), and the electrical resistance should be in the range of 12–20 kOhm

Strain modal response and vibration damping optimization of tower for wind power equipment

The safety of wind power equipment under dynamic load is one of the key factors to ensure sustainable energy recovery. In order to effectively improve the reliability of tower structure, the damage identification of flange bolt fracture based on strain mode was studied, and the vibration control and optimization scheme was proposed and verified. The dynamic response of the tower to wind load was calculated using the theory of Davenport spectrum. Combined with computational fluid dynamics, the dynamic load change law of the tower was obtained. Based on ANSYS Workbench, the modal simulation and analysis of the tower were carried out. Under different bolt damage conditions, the distribution characteristics of the strain modal shape of the tower in the axial and radial directions were obtained. The vibration damper was applied to the inside of the tower, and the vibration and stress at different positions under wind load were compared and analyzed to verify the specific vibration reduction and optimization effect. The results show that the strain modal shape of the tower cylinder has a significant peak at the damage site, and the peak height is positively correlated with the damage degree, indicating that the strain modal shape is highly sensitive to the damage. In addition, the vibration and maximum stress of the flange and top position of the tower have been effectively reduced by the shock absorber. The average amplitude of tower top can be reduced by 22.5 %, and the peak stress at the bottom flange position can be reduced by about 38 %.

Numerical performance of Hall current and Darcy-forchheimer influences on dissipative Newtonian fluid flow over a thinner surface

Present problem concerns may be found in a wide variety of various industries and can takes a shape of round toroid's, cones, cylinders, domes (Axisymmetric shape), and other shapes as well. When it comes to actual applications, they are represented by aerosol cans, submarine pressure hulls, cooling towers, offshore drilling rigs, radomes, nuclear reactors, and other similar objects. The aim of this research is to improve the performance of MHD flow using Darcy-Forchheimer, viscous dissipation, porous and a heat source. The viscous convective permeable flow flowing over a bullet-shaped item is examined. Using similarity transforms, the structure of nonlinear differential equations are converted into dimensionless ODEs. Employing bvp4c shooting technique to decrypt the findings. Influences of physical entities on velocity and temperature were sketched and briefly described. Physical behaviors of skin friction and heat transfer rates are explored. The fluid velocity drops for Eckert number Ec as ε < 1.0, and rises as ε > 1.0, The fluid velocity improves with Darcy-Forchhemier parameter Fr when stretching ratio ε < 1.0 or = 1 or >1.0. The enhancement of fluid temperature is observed with enhanced Ec. A enhance in the Darcy-Forchhemier parameter Fr associated with improvement in skin-friction. In the absence of viscous dissipation, hall current, porous and Dacy-Forchhemier influences, the outcomes are in splendid covenant with those of previous studies.

ЦИЛИДРИЧЕСКАЯ ОБОЛОЧКА С ЗАПОЛНИТЕЛЕМ

In the article we will consider cylindrical shells, their definition and properties of cylindrical shells, as well as examples of their application. We will also consider methods for calculating cylindrical shells. A cylindrical shell is a geometric body formed by turning a rectangle around one of its sides. The result is a cylinder whose bases are two parallel and equal rectangles, and the side surface is a surface formed by rotating the rectangle around one of its sides. Cylindrical shells have two main elements – the base and the side surface. The bases of the cylindrical shell are parallel and equal rectangles, and the side surface is a surface formed by rotating the rectangle around one of its sides. A cylindrical shell with filling is considered. They are in an axisymmetric stress state. The case is considered when the filler has the shape of a hollow cylinder or an elastic cone. The results of calculations for each case are presented.

Characterization of holocellulose extracted from agricultural and food processing byproducts via ecofriendly delignification pulping process

AbstractThis study investigated an ecofriendly peracetic acid delignification process to extract holocellulose from various fiber rich plant‐based byproducts (coconut palm spathe/leaf, apple pulp, wine grape pomace, hazelnut shell, and hemp fiber/hurd), and evaluated their physicochemical, morphological, and thermophysical properties in comparison with commercial cellulose nanofibers produced from wood. Holocellulose from coconut palm spathe has long fiber (~846.7 μm), whereas that from wine grape pomace and hazelnut shell exhibits a cylinder shape of particles with short fiber length (~123.8 and ~ 71.1 μm, respectively). Biofilms cast from apple pulp and hemp fiber holocellulose have higher degradation temperature (361 and 358°C, respectively) than biofilms from other materials, thus more thermally stable. All biofilms demonstrate high UV absorbance, and the biofilm cast from apple pulp holocellulose is transparent with smooth surface. Fourier‐transform infrared spectroscopy analysis confirms the presence of cellulose and hemicellulose as the main components in the biofilms, along with traces of residual lignin that remained after the extraction process. This study demonstrates that holocellulose with varied cellulose morphology and polymeric characteristics could be extracted depending on the type of byproducts and be employed to produce sustainable packaging materials.

Influence of thermal radiation and shape factor on a hybrid nanofluid flow over a permeable flat plate with cross-diffusion effects: An irreversibility analysis

Understanding and controlling the shape factors of nanoparticles in fluid flow problems is crucial for optimizing heat transfer, fluid dynamics, and various applications such as nanofluids, drug delivery systems, catalysis, and nanocomposites. By tailoring the shape of nanoparticles, researchers can manipulate their behavior, dispersion, and interaction with the fluid, thereby optimizing the desired outcomes in various fluid flow problems. The meticulous investigation uncovers the integration of entropy analysis in the investigation of the flow of convective magnetohydrodynamic hybrid nanofluid via a permeable flat surface, by considering the effects of Dufour, viscous dissipation, Soret, and thermal radiation. The governing equations are converted into a set of nonlinear ordinary differential equations using appropriate similarity transformations and then solved using the bvp4c solver, a MATLAB in-built function. We display the outcomes for three different shape factors: platelet, cylinder, and brick. The skin friction coefficient increases at a rate of 1.5089 for the brick shape, 1.5163 for the cylindrical shape, and 1.5212 for the platelet shape when the mixed convection parameter lies between 1 and 5. In this regard, it is important to point out that there is a direct connection between the increase in temperature transmission rate and a decline in the Dufour number ( Du ). It has been found that when 1 ≤ Du ≤ 2.4 , the Nusselt number decreases by 0.4786, 0.4618, and 0.4512 for brick, cylinder, and platelet shapes, respectively. A decline in the Sherwood number is noticed with an upsurge in the Soret number ( Sr ). There is a noticeable increase of 0.0442 in the Sherwood number for brick shape, 0.0438 for cylinder form, and 0.0435 for platelet form when 1 ≤ Du ≤ 2.4 . Furthermore, we have detected that an increase in the radiation parameter amplifies both the Bejan number and the profiles of entropy formation.

Examination of the vessel's shape, resistive force and volumetric-aqueous efficiencies to optimize the vessels' foil under noise propagation

There are several parameters in designing undersurface vessel forms, the most important of which is the hull's total strength, which includes the strength of the hull and its attachments. According to studies, 70 % of the total strength of the vessels is related to their hull only without attachments. The hull has three major parts: nose, cylinder, and heel. The advanced vessels' architecture has a parallel shape (cylinder shape). This cylindrical part is important in examining the used volume by pilots and vessel equipment. This paper uses the CFD method to examine the vessel's shape, and the resistive force and volumetric-aqueous efficiencies are extracted. An optimum profile is extracted by the values of resistive force and volumetric-aqueous efficiencies. The results indicate the significant effect of the hull form on the hydro-acoustic noise of the hull. In other words, by optimizing the hydrodynamic form of the hull, the noise propagation can be reduced as much as possible. Also, the linear slope of the optimized hull is not optimized more than the hull. This means that the turbulence caused by the optimized hull has a higher damping potential.

Eksplorasi Etnomatematika Pada Kue Jalo Khas Kampar

Jalo cake is a traditional cake found in several regions in Indonesia, including the Kampar area. This research aims to explain the relationship between the typical Kampar jalo cake and mathematics, especially in the cultural context of the Kampar community. The methods and approaches used are exploratory and ethnographic. Data was collected through literature study, observation, interviews and documentation. Researchers rely on field observations and interviews in collecting data. The uniqueness of this research is that the Kampar community and students are not yet aware that jalo cake is related to mathematics learning. The connection between mathematics and jalo cakes includes material about triangular shapes and cylinder shapes, which are studied in the 5th grade of elementary school.