Cross-sectional Shape Research Articles

Effects of cross-sectional shape on flow and heat transfer of the laminar flow of supercritical carbon dioxide inside horizontal microchannels

Supercritical carbon dioxide (sCO2) flow at the micro scale provides an excellent heat transfer solutions for a range of microelectronics cooling applications. The cross-sectional shape of the microchannel (in combination with the abruptly changing thermophysical properties of sCO2) affects the heat transfer and flow characteristics, but these effects are not well understood at constant wall temperatures as most of the previous studies were performed at constant surface heat fluxes. Current study numerically investigated, using CFD, the effects of different cross-sectional shapes, such as circle, equilateral triangle, semi-circle, and square, in zero gravity (space) and in terrestrial conditions, at constant wall temperatures.In all cases, the hydraulic diameter of the microchannel was 100 μm, the total length was 27 mm, and the heated length was 25 mm. A total of 216 cases were analyzed to predict the effects of surface temperature ranging from 310 to 330 K, pressures ranging from 8 to 10 MPa, and Reynolds numbers from 100 to 500 on the heat transfer and flow. It was revealed that the microchannel with triangular cross-section has the highest heat transfer rate, highest mass flow rate, and lowest pressure drop both in zero gravity and in terrestrial conditions. The total surface heat transfer rate for the triangular microchannel was about 49% higher than the circular microchannel at a pressure of 8 MPa, around 53% higher at 9 MPa, and about 55% higher at 10 MPa. However, the average surface heat transfer coefficient displayed a complex behavior, and it depends on the combination of surface temperature, Reynolds number, and operating pressure. The surface heat transfer rate and pressure drop were increased for all shapes at terrestrial conditions, emphasizing that the effects of buoyancy cannot be neglected. Overall, this study revealed a complex behavior of the flow of sCO2 inside microchannels of different cross-sectional shapes, and the triangular cross-section performed better than other shapes.

CFD Analysis of Pressure Drop Reduction in PEMFC Flow Channels with Distinct Cross-Section Shapes

Proton exchange membrane fuel cells (PEMFCs) have great potential to produce renewable, sustainable and clean energy and reduce air pollutants to mitigate climate change. PEMFCs consist of distinct parts including anode and cathode bipolar plates having flow channels, gas diffusion layers, catalyst layers, and membrane. The flow channel geometry influences the flow and pressure drop characteristics of the channel and cell performance. In this work, a three-dimensional (3D) CFD model is built employing SOLIDWORKS and ANSYS Workbench. The innovative configurations are generated by changing the half of 0.2 x 0.2 mm square channel to 0.3 x 0.1 mm, 0.3 x 0.15 mm, 0.3 x 0.2 mm and 0.3 x 0.25 mm rectangular section at the top. The results showed that increasing rectangular section height significantly reduced pressure drop at the anode and cathode with a slight decrease in the current density at 0.4 and 0.6 V. The new configuration with 0.2 x 0.1 mm half square section at the bottom and 0.3 x 0.25 mm rectangular section at the top decreases the current density, anode and cathode pressure drop of 11%, 69% and 58%, respectively in comparison to 0.2 x 0.2 flow channel at 0.4 V. Taking into account pressure loss along the flow channels, this configuration is a good option to improve the cell performance.

Impulsive impact of a twin hull

An impulsively starting motion of two cylindrical bodies floating on a free liquid surface is considered. The shape of the cross-section of each body and the distance between them are arbitrary. The integral hodograph method is advanced to derive the complex velocity potential defined in a rectangular parameter region in terms of the elliptic quasi-doubly periodic Jacobi theta functions. A system of singular integral equations in the velocity magnitude on the free surface and in the slope of the wetted part of each body is derived using the kinematic boundary condition, which is then solved numerically. The velocity field, the pressure impulse on the bodies and the added mass coefficients of each body immediately after the impact are determined in a wide range of distances between the bodies and for cross-sectional shapes such as the flat plate and half-circle.

Assessment of the meshed screens operability to reduce dust emissions of bulk cargo from the ports open warehouses

Currently, the coal terminals of sea and river ports have a significant negative impact on the environment through their activities. The operation of the terminals technological equipment leads to high concentrations of dust in the air and dust emissions of bulk cargo. The main sources of dust emissions and dust removal are open coal storage warehouses. Recently, dust screens have been used to combat dusting in open coal warehouses and port terminals. However, the processes of wind flows interaction with stacks of port open slads and meshed screens have not been studied enough. In this regard, the purpose of this work is to evaluate in laboratory conditions the operability of meshed screens to reduce the dustiness of the air and the dust emission of bulk cargo during its storage in port open warehouses. During laboratory studies, models of open warehouses stacks are carried out at a certain scale, which allows you to use the full-scale bulk cargo and real meshed screens. The main results of these studies are the following conclusions: meshed screens are workable and effective devices for reducing the speed of wind flow inside the perimeter of the screen; the shape of the stack cross-section does not affect the screen performance; the level of the meshed screen performance to reduce the air dustiness and the amount of dust emission from the warehouses stacks with the different shape of the cross-section depends on the direction and speed of the wind flow. The use of soft meshed screens located along the perimeter of the open coal warehouse stack makes it possible to reduce air dustiness and dust emission at a wind speed of 5 m/s by an average of 1.8 times, and at a wind speed of 10 m/s by an average of 2.5 times.

Effect of nanocavity geometry on nanoscale nucleate boiling heat transfer

In recent years, surfaces with nanocavities have been identified to considerably improve boiling heat transfer, that is highly promising for advanced thermal energy systems. To boost developments in nanostructured boiling surfaces, effects of nanocavity geometry on nucleate boiling at the nanoscale are systematically studied for the first time by utilizing molecular dynamics simulation. Three typical nanocavities with rectangular, semicircular, and triangular cross-sectional shapes are constructed, which have the identical width and depth (8 nm and 4 nm). Moreover, three representative wetting conditions corresponding to different solid-liquid interaction strengths are further considered to provide a comprehensive understanding of geometry effects. The results manifest that nanocavity geometry effect on nucleate boiling can be attributed to the differences in their solid-liquid contact area and solid-liquid interactions play a vital role in reinforcement effectiveness. When the solid-liquid interaction is sufficiently strong (energy coefficient equals 1.5, termed ultra-superhydrophilicity), variations in nanocavity geometries will induce remarkable effects on boiling performance. Among three geometric configurations, the rectangular nanocavity exhibits the highest heat transfer efficiency and achieves maximum boiling enhancement, including significant improvements in bubble nucleation and growth, as well as critical heat flux. This study provides an essential insight into nanoscale boiling reinforcement mechanism.

Experimental Study on Single Fiber Tensile Properties of Sisal Fibers Using a Digital Image Correlation Method as a Strain Measurement

ABSTRACT The development of natural fibers in engineering applications requires an accurate measurement of their dimensional characteristics and mechanical properties. Fiber cross-sectional area (CSA) obtained from lateral dimensional measurements should consider the specific cross-sectional shape (CSS) of the fibers and their wide lengthwise variations. In this study, the dimensional measurements of water-retted and unretted sisal fibers were conducted by laser scanning microscopy (LSM) and calculation-based methods. Single fiber tensile tests were performed using the digital image correlation (DIC) method. Results show that the diameters of water-retted and unretted fibers measured by LSM were 233 ± 45 µm and 236 ± 42 µm, respectively. The diameters of water-retted and unretted fibers obtained by calculation were 192 ± 17 µm and 178 ± 20 µm, respectively. The tensile strengths of water-retted and unretted fibers were 679 ± 118 MPa and 718 ± 106 MPa, respectively. The strain at failure and elastic modulus of water-retted and unretted fibers were 2.0 ± 0.6% and 34 ± 8 GPa, as well as 1.5 ± 0.2% and 48 ± 6 GPa, respectively. Water retting seems to predominantly influence the strain at failure and elastic modulus of sisal fibers, as confirmed by the ANOVA analysis.

Database-driven lightweight design for axle housing of heavy-duty truck

Rapid and efficient design methods of axle housing are an increasingly important area for the lightweight design of heavy-duty trucks. Here, a database-driven lightweight design method for axle housing is developed. A theoretical analysis is conducted to explore the relationship between the shape and maximum stress of cross-sections. Subsequently, A double super-ellipse equation is applied to generate massive cross-sections with different shapes and sizes. The secondary development module is constructed to achieve the parametric modeling, finite element analysis, and result analysis of axel housing. Finally, the proposed database-driven lightweight design is employed to carry out the lightweight design of axel housing under different design criteria. The results show that compared to their counterpart, the mass of axel housing using Q345 and Q420 is decreased by 10.3% and 18.9%, respectively, and their maximum stress are declined by 32.9% and 20.8%, respectively, under the design criteria of equal strength. Under the design criteria of specified safety factors, the mass and maximum stress of axel housing are decreased by 11.7% and 25.0%, respectively. This investigation offers some important insights into the lightweight design of tube components.

An application of stability charts to prediction of buckling instability in tapered columns via Galerkin’s method

This work tackles the mathematical modeling of buckling problem to obtain their critical loads in tapered columns subjected to concentrated and axial distributed loads. The governing model is a general eigenvalue problem that has no exact solution due to some new terms included. A semi-analytical technique satisfying the boundary conditions is proposed for the solution procedure. The minimum residual Galerkin’s method is suggested due to its effectiveness as a semi-analytical tool for the buckling problem to obtain the buckling shape modes by using admissible periodic functions. The study investigates the buckling instability and the responses of tapered columns with different periodic trial shape functions as approximations to the exact solutions. Based on the eigenvalue problem, Galerkin’s method is employed to obtain the transition curves to represent the critical loads. The stability charts (Ince–Strutt diagrams) among the parameters of the problem are proposed to explain the elastic stability of different tapered columns subjected to different shapes of cross sections and distributed weights. Consequently, the influences of the included parameters on the critical buckling loads are discussed. Among the different tapered columns presented, some parameters in the proposed distributions have a big influence on the critical buckling load and the creation of the instability regions in the chart for the clamped-clamped boundary conditions. The results are verified using the analytical solutions for some specific known problems.

Axial Crushing Theory and Optimization of Lattice-Filled Multicellular Square Tubes.

A lattice-filled multicellular square tube features a regular cross-sectional shape, good energy consumption, and good crashworthiness, which is suitable for the design of energy absorbers in various protection fields such as automobiles, aerospace, bridges, etc. Based on the super folding theory, two reference planes are set to refine the energy consumption zone of the super folding element in this study. The energy consumption calculation of convex panel stretching is involved, and the critical crushing force formula is introduced in this study. Meanwhile, the calculation method from a single-cell square tube to a multicellular thin-walled square tube is extended and the structural optimization is investigated, in which the NSGAII algorithm is used to obtain the Pareto front (PF) of the crashworthiness performance index of the square multicellular tubes, the Normal Boundary Intersection (NBI) method is adopted to select knee points, and the influence of different cross-sectional widths on the number, as well as the thickness, of cells are discussed. This study's results indicate that the theoretical value is consistent with that obtained from the numerical simulation, meaning that the improved theoretical model can be applied to predict the crashworthiness of multicellular square cross-sectional tubes. Also, the optimization method and study results proposed in this study can provide a reference for the design of square lattice multicellular tubes.

Numerical investigation of supercritical flow and heat transfer mechanism in printed circuit heat exchanger (PCHE) channels

A numerical study is conducted to investigate supercritical hydrogen flow and heat transfer mechanisms and characteristics in printed circuit heat exchanger (PCHE) channels. The impact of large variations of the thermal-physical properties due to a wide range of operating temperatures have been studied and analyzed in detail. The heat transfer mechanisms of supercritical hydrgen under horizontal and vertical flow conditions are studied numerically. In addition, the influence of different cross-section shapes of the channel is also analyzed. The results show that asymmetrical fluid temperature distributions near the top wall and bottom wall due to the buoyancy effect result in heat transfer deterioration. Spiral flow occurs in the heat transfer deterioration region, which further confirms that the heat transfer deterioration is related to the spiral flow effect caused by the buoyancy effect. The heat transfer coefficient without gravity is lower than that with gravity, indicating that the buoyancy effect enhances the overall heat transfer in the horizontal circular channel. Furthermore, the fluid temperature in the vertical upflow channel decreases slowly from the near wall to the core area, while the fluid temperature in the vertical downflow channel changes sharply, which directly leads to the difference in the temperature gradient near the wall. Compared with the square cross-section channel and semicircular cross-section channel, the supercritical hydrogen can achieve greater heat transfer performance in the circular cross-section channel.

Crashworthiness in preliminary design: Mean crushing force prediction for closed-section thin-walled metallic structures

To design crash structures for disruptive aircraft designs, it is required to have fast and accurate methods that can predict crashworthiness of aircraft structures early in the design phase. Axial crushing is one of the key energy absorbing mechanisms during a crash event. In this study, various analytical models proposed for calculation of mean crushing force for thin-walled tubular structures are compared with a database of numerical and experimental values to ascertain their accuracy. Improvements to some of the models have also been proposed. Finally a generalized model based on the studied and improved analytical models for prediction of mean crushing force for closed section thin-walled tubular structures is introduced. The generalized model demonstrates high accuracy when compared against experimental/numerical dataset as evidenced by a high coefficient of determination (R2) value of 0.97 and can therefore be used to estimate the mean crushing force for closed-section thin-walled metallic tubular structures with various cross-sectional shapes and crushing modes early in the design phase.

A Generalized Nonlinear Beam Element for Slender RC Members Using a Polygonization Section Approach—Part I: Theoretical Formulation

A mathematical model for RC beam elements is presented that falls into the category of distributed inelasticity models discretizing the cross-section in polygons (trapezoids, triangles). The models falling into these categories are considered to be able to describe in the best manner the inelastic behavior of the element across its whole clear length, since its response results from the numerical integration of the stiffnesses of its cross-sections, while presenting an ideal combination of accuracy, simplicity, and computational cost. The behavior of the cross-section is described through the constitutive relationships σ–ε of its materials for cyclic loading. The main objectives for the development of the proposed mathematical model are as follows: (a) the increased accuracy of the results compared to existing experimental ones; (b) the limitless generalization of its application, regarding of the cross-section shape; and (c) the elimination of the numerical problems presented by the application of other related models, a fact that leads to their impractical use in real three-dimensional structures. The proposed model falls under the category of distributed inelasticity models. This paper focuses on its initial version, which targets slender beam elements with negligible shear and bond-slip effects (i.e., with ribbed bars, sufficiently anchored). Thus, it is applicable to 2D and 3D framed structures that fulfill these conditions, while its modular structure allows for future adjustments for the inclusion of other effects.

EFFECT OF INNER BOUNDARIES GEOMETRY ON NATURALCONVECTION HEAT TRANSFER IN HORIZONTAL ANNULI

An analytical modeling of natural convection in physically-based analysis is developed for investigate free convective heat transfer in horizontal eccentric annulus between a circular outer cylinder and heated different shape inner envelope with used four models of the shapes of the inner cross section of (circular, triangular, square and hexagon inner boundary). The main objective of this paper was taking a composite model based on asymptotic solutions for three limiting cases: pure conduction, laminar boundary layer convection and transition flow convection. Laminar conditions up to Rayleigh number RaPi of 5×104 were investigated. By using data from MATLAB simulations for a wide range of two cylinder temperature difference in order to study the effects of annulus diameter ratio, Rayleigh number, and the cross section geometries of inner cylinder on the Nusslte number and the ratio of thermal conductivity. The numerical result illustrated for the circular the increasing the Rayleigh number leading to slightly increasing the non-dimensional Nusslte number with various value of annulus diameter ratio and when used the high annulus perimeter ratio (Po/Pi( about (4.5,2.6,1.6 and 1.175). There is rapid increasing in the non-dimensional ratio of thermal conductivity with increasing the Rayleigh number at the high values of (Po/Pi(, and the result showed that the non-dimensional ratio of thermal conductivity and the Nusslte number values of the (triangular, square and hexagon) less than in the case of circular inner boundary, but the hexagon model showed the Nusslte number more that than in the (triangular and square). the mathematical results compared with model developed by pervious numerical the model and data are in good agreement, with an average RMS difference of 10.6% for the circular annulus of dimensional Nusselt number (NuPi) and less than 4.9 % and 9.8% for the square inner geometry non-dimensional ratio thermal conductivity.

Measuring the behavior of the acoustic standing wave exiting a flue organ pipe: Is the decay sinusoidal or exponential?

Correctly predicting the playing frequencies of a musical instrument is dependent on the length of the resonator with the addition of an end correction. There are multiple theories describing this end correction, perhaps the simplest being that the end correction of a pipe is a physical extension of the sinusoidal pressure standing wave inside the pipe. However, recent optical imaging of the flow in a flue organ pipe found an unexpected exponential decay of pressure just outside of the pipe. This work looks to validate those findings acoustically. A flue organ pipe was played at the 1st, 5th, and 7th harmonics and the pressure just inside and immediately outside the end of the pipe played was measured using a zero-degree PU Match Microflown sound intensity probe. These measurements were fit to both exponential and sinusoidal curves and compared to the optical images. While an exponential trend is in fact apparent in some cases, the goodness-of-fit appears to be dependent on which harmonic is sounding. Future work includes exploration of a potential transitional region, assessing the impact of altered pipe geometry (both cross-sectional shape and size), and investigating potential sensor interference by using other measurement equipment.

A structural optimization analysis of cable-driven soft manipulator

Cable-driven soft robots hold significant potential for surgical and industrial applications, yet their performance and maneuverability can be further enhanced through design optimization. By optimizing the design, factors such as bending angles, manipulator deformation, and overall functionality can be directly influenced, leading to improved interaction with the environment and more accurate task performance. This article presents a physics-based design optimization approach for cable-driven soft robotic manipulators, aiming to enhance bending performance through structural design enhancements. Four design criteria, namely, cross-sectional shape, material, gap shape, and gap size, are considered in the optimization process. Given the inherent nonlinearity of soft materials, finite element modeling techniques are employed to analyze the effects of modifying each design parameter on displacement and bending angle. The manipulator’s design is evaluated using ABAQUS/CAE, and an analysis of variance test is conducted to identify significant performance differences among the design parameters. The results reveal that material variation has the most substantial impact, followed by gap shape and gap size. Based on subsequent parameter optimization, Dragon Skin 10 is determined to be the optimal material for bending motion, while a trapezoidal gap shape is preferred. In addition, a genetic algorithm is utilized to select a maximum gap size of 8.87 mm. These findings provide valuable insights into key design principles for cable-driven soft manipulators, aiming to enhance flexibility and reduce actuation forces. By establishing a fundamental understanding of the relationship between morphology and motion capability, this methodology demonstrates an effective simulation-driven optimization approach that incorporates the nonlinear elastic behavior of materials to improve performance. Overall, this work establishes a framework for optimizing cable-driven architectures to suit various applications in the field of soft robotics.

Mesoscale modellings of axial compressive failure of geometrically-similar CFST columns at low temperatures

In this paper, a thermo-mechanical sequential coupling mesoscopic simulation method was established and verified, which considered the interaction between steel tube and meso-components of concrete due to the difference in thermal parameters, as well as the low-temperature effect on mechanical parameters. On the basis of heat conduction analysis, the damage evolution and failure mechanism of CFST column under axial compression were subsequently revealed, and the effects of low temperature (20, −30, −60 and −80 °C), cross-section size (160, 320, 480 and 640 mm), width-thickness ratio (27, 36, 53 and 107) and cross-section shape (square and circular) on axial compression performance and the corresponding size effect of CFST columns were quantitatively analysed. Research results show that the low-temperature action can enhance the nominal peak strength and residual strength of CFST column, but weaken the ductility. As the cross-section size increases from 160 to 640 mm, all the nominal peak strength, nominal residual strength and peak strain of circular CFST column decrease with the maximum reductions of 16.2, 28.7 and 16.9%, respectively. Besides, the low-temperature action can enhance the size effect on nominal peak strength of CFST column with the maximum increase of 68.8%. Whether at ambient or low temperature, the size effect on nominal peak strength of square column is stronger than that of circular one. The size effect behaviour on axial compressive peak strength at various temperatures can be also well described by the previous proposed prediction formula. The research results of this paper can provide reference for the engineering application of large-sized CFST columns in the extreme low-temperature environment.

Effect of flow channel cross-section shape on the performance of proton exchange membrane electrolysis cell

To study the thermal and mass distribution in proton exchange membrane electrolytic cells (PEMEC), a two-phase numerical model of a single-channel electrolytic cell was established. The polarization performance and gas-heat distribution in a single-channel electrolytic cell under five different flow channel cross-sections (rectangle, trapezoid, inverted trapezoid, triangle, and circle) were studied. The findings indicate that the inverted trapezoidal flow channel’s gas buildup effect is rather severe in both the catalytic and diffusion layers. In the trapezoidal flow channel, the temperature of the proton exchange membrane region is lower, and the electrochemical performance of the rectangular flow channel electrolytic cell is the best, with an improvement rate of up to 11.47%. The electrochemical performance of the triangular and circular flow channels is the worst.

Investigation into the Effects of Cross-Sectional Shape and Size on the Light-Extraction Efficiency of GaN-Based Blue Nanorod Light-Emitting Diode Structures

We investigated the effect of cross-sectional shape and size on the light-extraction efficiency (LEE) of GaN-based blue nanorod light-emitting diode (LED) structures using numerical simulations based on finite-difference time-domain methods. For accurate determination, the LEE and far-field pattern (FFP) were evaluated by averaging them over emission spectra, polarization, and source positions inside the nanorod. The LEE decreased as rod size increased, owing to the nanorods’ increased ratio of cross-sectional area to sidewall area. We compared circular, square, triangular, and hexagonal cross-sectional shapes in this study. To date, nanorod LEDs with circular cross sections have been mainly demonstrated experimentally. However, circular shapes were found to show the lowest LEE, which is attributed to the coupling with whispering-gallery modes. For the total emission of the nanorod, the triangular cross section exhibited the highest LEE. When the angular dependence of the LEE was calculated using the FFP simulation results, the triangular and hexagonal shapes showed relatively high LEEs for direction emission. The simulation results presented in this study are expected to be useful in designing high-efficiency nanorod LED structures with optimum nanorod shape and dimensions.

Data-driven initial peak crushing force prediction of hybrid tubes

Accurately predicting the initial peak crushing force (IPCF) of the CFRP/metal hybrid structure is of great significance for the high-efficiency energy absorption of energy-absorbing elements and ordered deformation of combined energy-absorbing devices. Due to the significant differences in material properties between CFRP and metal and the high complexity of cross-sectional shape, a combined method of machine learning and mechanism analysis is proposed for predicting the IPCF of CFRP/Al hybrid energy-absorbing tube. First, a high-precision finite element model validated by the axial and oblique experiments is conducted to generate the dataset for predictive analysis. Second, a sample space through the design of experiment (DOE) is established for data fitting between structural parameters and IPCF based on traditional response surface model (RSM). It is found that traditional RSM method can successfully predict the IPCF of the single-cell hybrid tube, but cannot effectively predict the IPCF of the multi-cell tube due to the strong coupling effect between inner and outer plates. To address the issue of the lack of accurate correspondence between structural parameters and IPCFs in multi-cell hybrid tube, the indicator of relative density is proposed to characterize complex cross-sectional features. Surprisingly, there is a strong correlation between relative density and IPCF where multi-cell tubes with the same relative density have almost the same IPCF. Third, different artificial neural networks (ANN) are trained by a pre-simulated IPCF database of CFRP/Al hybrid energy-absorbing tube depending on the parameter characterization scheme based on mechanism analysis. In order to enhance the network's performance, the optimal configuration parameters of the neural network, including the number of layers and nodes, are ascertained through a combination of K-fold cross-validation and the Grid Search method. As a result, compared with the traditional RSM and Kriging model, the IPCF of CFRP/Al hybrid energy-absorbing tube can be predicted in small samples with high accuracy using the optimal ANN model. Finally, Through the comparative analysis of the IPCF of hybrid tubes with reported multi-cell configurations, it is found that the prediction model proposed in this paper has good generalization ability, which can be used to predict more complex types of multi-cell tube configurations. The present study offers important suggestions for the overall control of multi-materials hybrid energy-absorbing tube and the ordered deformation of combined energy-absorbing devices.

금강유역권 축소모형농공구의 형태와 특징

These days, relics that used to have regional specificity tend to deviate from their specificity due to the active cultural property excavation research. It is necessary to recognize the newly identified area. Therefore, among the archaeological materials that strongly reflect regional specificity, we paid attention to the Miniature farming tools accumulated around the Geum River basin. The Miniature farming tools can be divided into ttabi type, cheolseo type, iron axe type, and sickle type. Data from the Geum River basin also show high excavation rates for Iron Axe type and sickle type, although the warm and cheolseo type are also identified. Cheoljun is one of the characteristic iron artifacts excavated from the Geum River basin. Compared to the Daegaya sphere, this was identified as a ttabi-type Miniature farming tool, and the plane shape and cross-sectional shape were considered to be more likely to have been produced under the influence of the Daegaya sphere rather than generated and produced within the Geum River basin. Iron axe-type Miniature farming tools are again divided into I-shaped and V-shaped in crosssectional form, and the I-shaped is the same as or similar to those confirmed in the Daegaya sphere, so it is thought to be highly relevant. On the other hand, the V-shaped is also excavated from the remains of the Proto-Three Kingdoms Period, which is confirmed around the Geum River basin, and is similar to the form of Iron axe, which has been produced and used for a long time, so it is thought that the traditional method was inherited. Although there is a limit to linking data excavated from the Geum River basin with Miniature farming tools excavated from the Daegaya sphere, data that are likely to have been produced in a manner similar to that of the Daegaya sphere in both plane and cross-sectional shapes were identified. From these data, it can be seen that there are also data that are more likely to have flowed into Baekje sphere from Daegaya sphere than from Baekje sphere.