Junction Of Wall Research Articles

Effects of aluminized charge structures on blast wave propagation and the parameters of partially confined explosions

The composite charge structure may have the potential to enhance the overall damage capability of the weapon. In this regard, three-dimensional LS-DYNA simulation software (dynamics calculation software from LSTC) was used to simulate the explosion process of charges in a partially confined space. The effects of different aluminized charge structures on the propagation and parameters of blast waves in a cubic cabin structure with a pressure relief port were obtained. The results showed that the reflected waves generated local pressure convergence at the junction and corner areas of adjacent walls in the cabin structure. The numbers of significant reflections of the blast waves at the center and corners of the wall were 3 and 2, respectively. The overpressure of the reflected wave at the corner was more than 3.2 times that at the center of the sidewall. Moreover, the number of reflections, overpressure ratio, and charge structure were not directly related. The advantages of composite structure charges in enhancing the overpressure and wave velocity of incident waves and the overpressure and impulse of reflected waves were not significant. However, the internal and external composite charge structure had more advantages than did the upper and lower structures, and its impulse TNT equivalent reached more than 70% of that of a single-structure explosive. The results can provide theoretical support and technical guidance for the design of charge structures and cabin structures.

Numerical investigation on influences of injection angle of bottom blowing bubbles on multiphase flow characteristics and wall erosion of converter

In this work, a novel bottom blowing approach based on inclined injection bubbles to enhance the multiphase flow mixing is proposed. An Eulerian-Eulerian model, validated via published experimental data, is established to numerically reproduce the stirring process of a bottom blowing converter. The effects of injection angle on the multiphase flow characteristics and wall erosion are then systematically investigated. Firstly, the influence of bottom blowing flow rate (10 m/s, 14 m/s, 20 m/s) on the mixing efficiency is discussed. Then, the effects of injection angle (0°, 5°, 10°, 15°, 20°) on the flow characteristics, mixing efficiency and wall erosion are studied in detail based on the bottom blowing flow rate of 14 m/s. The results show that increasing the bottom blowing flow rate is beneficial to shorten the mixing time. With the increase of the injection angle, the mixing time first decreases and then increases. As a result, the optimal angle for the most efficient mixing is determined as 5° when the flow rate is 14 m/s. When the injection angle is 5°, the air velocity on the axis and the negative tangent line is maximum. But the velocity is minimal on the positive tangent line. The injected air forms bubble plume that promotes the circulation of water. The most serious erosion area of the converter wall is located at the junction of molten steel surface and converter wall, followed by vicinity of the tuyere. However, with the increase of the injection angle, the average wall shear stress fluctuates only slightly. The obtained results are helpful to better understand the mechanism of bubble flow field in gas-liquid two-phase and also to improve the smelting efficiency in iron and steel metallurgy.

Enhancing seismic performance of historic mosques through retrofitting measures

Historic mosques are structures that are highly sensitive to seismic events. Strengthening these buildings, which have been exposed to earthquakes throughout history, and ensuring their safe transfer to future generations is crucial. This research study focuses on three significant historic mosques in the eastern province of Türkiye, Erzurum. Their seismic performance, which has not been extensively studied in the existing literature, is investigated using finite element analysis. Dynamic analyses are conducted, utilizing seismic records from notable earthquakes that have caused significant damage to historic mosques in Türkiye, including the 1992 Erzincan, 1997 Düzce, and 2023 Kahramanmaraş earthquakes. As a result of dynamic analyses, the seismic vulnerability of the considered mosques has been determined. These vulnerable areas include the junctions of load-bearing walls, the dome ring, and the main dome. Based on these findings and considering recommendations from the literature, cost-effective and practical retrofit strategies are proposed to enhance the seismic performance of the mosques. The proposed strengthening aims to improve the interaction between load-bearing walls (diaphragm effect) and reduce displacements in the dome. Dynamic analyses are performed using the retrofitted models to assess the effectiveness of the proposed retrofit measures. These assessments were made considering displacements obtained from the dome and walls and the distribution of global damage. The results of 18 dynamic analyses confirm the efficacy of the suggested retrofit configurations in mosques featuring square plan layouts and single dome architectural styles.

Hygrothermal performance of corners and floor junctions of timber-framed exterior walls: a simulation study

Corners and basement junctions of different timber-framed walls were studied by computer simulation using Delphin 5.8.3 software. Wooden cladding and brick veneer were compared with each other, as well as different wind barrier solutions. Both internal and external corners were studied, first assuming them airtight and then modelling an air leak. Simulations were performed both in present and future climate conditions. According to the results, the walls with wooden cladding and brick veneer had a big difference in their hygrothermal behaviour. Mould index rose considerably after construction in sole plate of brick clad wall, even if the plate was originally dry. Wet sole plates dried up very slowly. Almost all corner junctions of walls with wooden cladding performed well when there was no air leak. Corners of brick clad walls were more problematic. With an air leak, all studied walls developed considerably high mould indices, underlining the importance of building airtightness.

The emergence of three-dimensional chiral domain walls in polar vortices.

Chirality or handedness of a material can be used as an order parameter to uncovertheemergent electronic properties for quantum information science. Conventionally, chirality is found in naturally occurring biomolecules and magnetic materials. Chirality can be engineered in a topological polar vortex ferroelectric/dielectric system via atomic-scale symmetry-breaking operations. We use four-dimensional scanning transmission electron microscopy (4D-STEM) to map out thetopology-driven three-dimensional domain walls, where the handedness of two neighbor topological domains change or remain the same. The nature of the domain walls is governed by the interplay ofthe local perpendicular (lateral) and parallel (axial) polarization with respect to the tubular vortex structures. Unique symmetry-breaking operations and the finite nature of domain walls result in a triple pointformation at the junction of chiral and achiral domain walls. The unconventional nature of the domain walls with triple point pairs may result in unique electrostatic and magnetic properties potentially useful for quantum sensing applications.

Flexural Behavior of Slabs with Different Anchorage Locations of Longitudinal Reinforcing Bars in a Composite Basement Wall Junction

Although the anchorage location of longitudinal reinforcing bars is a significant design element for flexural behavior, the conventional anchorage method of using longitudinal reinforcing bars has limited applications in new types of structures, such as composite structures. Therefore, this study examined the effect of the anchorage location of longitudinal reinforcing bars on the flexural behavior of slabs at the junctions of developed composite basement walls (SCBW) under monotonic loads at the top free end of the slab. The test results showed that the slab with longitudinal reinforcing bars anchored to the cast-in-place pile (CIP) in the composite basement wall exhibited ductile behavior accompanied by the yielding of the longitudinal reinforcing bars, a relatively wide area of vertical cracks propagating along the slab length, and a plastic plateau flow in the load–deflection relationships. In particular, the slab with longitudinal reinforcing bars anchored to the basement wall experienced severe crack concentration localized at the junction of the composite basement walls and concrete spalling in the basement walls, which resulted in no yielding of the longitudinal reinforcing bars and no cracks in the slab. Consequently, in a slab, it is recommended that longitudinal reinforcing bars be anchored into the CIP by penetrating the steel plate.

Effects of the airfoil probes on the aerodynamic performance of a transonic compressor cascade

The airfoil probe is typical instrumentation for measuring total pressure/temperature in the research fields of turbomachinery. Besides causing measurement error itself, it also generates extra flow loss inevitably and further affects the measuring accuracy. This paper utilizes the Reynolds-averaged Navier Stokes (RANS) and high-fidelity methods to understand the effects of airfoil probes on the aerodynamic performance of a compressor cascade. With the inclusion of airfoil probes, the load capacity and the shock waves decline, to some extent, mainly because of the streamwise vortex. The shedding vortex induced by the probes triggers an earlier and non-separated flow transition, which contributes to a suppression of the separation bubble on the suction surface and a reduction of the profile loss. However, through the quantitative traceability analysis of the flow loss, the extra loss is generated and redistributed to the overall flow field. The separated flow forms at the junction of the end wall, blade, and probe's pipes, due to the high adverse pressure gradient aggravated by shock waves. It is one of the reasons why the measuring accuracy of airfoil probes is quite sensitive to the Mach numbers. The Delayed-Detached Eddy Simulation (DDES) shows superiority in capturing small-scale coherent vortex structures. The shedding streamwise vortex generated by the probe's pipe is distinguished for the first time. Its transport progression to the wake region is revealed basically, which has been masked previously by the conventional RANS method. In addition, due to the supplement of the streamwise vortex generated by probes, the wake vortices maintain a higher shedding frequency. This work offers a glimpse of the complex fluid mechanisms in a transonic regime, which suggests carefully considering the size of instruments in the design and measurement process.

Pilonidal sinus of external auditory canal as unpredicted lesion: rarest case presentation and review of literatures

BackgroundPilonidal sinus (PNS) is considered as a benign lesion of hair-bearing areas, particularly at the sacrococcygeal area. It is presented as a hole or tunnel in the skin. It may be filled with fluid or pus resulting in the formation of a cyst or abscess. Although PNS is a well-established lesion in general surgery as well as dermatology specialties by its occurrence at the sacrococcygeal region, but the surprising presentation of PNS is that at ENT specialty by its appearance at the external auditory canal (EAC), which is deemed unpredicted lesion at this particular region.Case presentationNine years female Libyan child has been presented with a history of persistent offensive bloody stained yellowish discolored left ear otorrhea a few months before her presentation. The local examination including the microscopic examination revealed evidences of a grayish-pinkish pedunculated polypoidal mass raised from the junction of the superior wall with the anterior wall of the EAC, at the site of the junction between the cartilaginous and bony portions of EAC. The temporal bone CT scan revealed evidences of radiolucent soft tissue density mass arising from the wall of the EAC at its anterior-superior junction, with the intact tympanic membrane as well as the middle ear cavity. This was most probably in favor of the suggestion of granulation tissue or aural polyp. The mass was completely excised as one piece from its pedicle and sent for histopathological evaluation, which was in favor of the diagnosis of PNS.ConclusionWe consider this case for reporting because of its scarcity and unexpected lesion at EAC. To the best of our knowledge, our case constitutes the second case of the EAC specifically, and the third case of external ear generally reported in the world. Thus, we tried to illustrate this unique and rare EAC lesion concerning how it is clinically as well as pathologically presented. In addition, we tried to review the literatures to elucidate whether this rare lesion has been reported before.

Seismic performance and numerical analysis of steel plate-fiber reinforced concrete composite coupling beams

To improve the seismic performance of reinforced concrete coupling beams with small span-to-height ratio, a steel plate-fiber reinforced concrete coupling beam is proposed in this paper. Quasi-static tests of a steel plate-fiber reinforced concrete composite coupling beam and a steel plate-reinforced concrete composite coupling beam have been completed. Seismic performance metrics such as failure process and bearing capacity were analyzed. Finite element software was used to analyze the stress development of concrete, steel plates, and steel rods coupled to beams under three operating conditions, as well as the distribution laws of axial forces, shear forces, and bending moments of the embedded plates. The results show that steel plate - fiber reinforced concrete coupling beam has high bearing capacity, energy dissipation capacity and ductility. The addition of fibers effectively controls the expansion of the initial cracks in the concrete and works better with steel plates. The maximum stress of the embedded steel plate is at the junction of the beam walls. The axial force of the coupling beam steel plate is U-shaped, which is subjected to a large axial force at the end and the minimum axial force in the middle, but the shear force at the end of the coupling beam steel plate is the smallest, and the closer to the middle, the greater the shear force.

Numerical Investigation of the Thermal Behavior of Cracked RP-3 in Rectangular Cooling Channels under Different Inclinations.

The pyrolysis effect of aviation kerosene is common in the regenerative cooling process of hypersonic aircraft scramjets. To find out the effect of inclination variation on the characteristics of aviation kerosene RP-3 considering thermal cracking in a regenerative cooling rectangular channel, a detailed chemical mechanism of RP-3 pyrolysis is introduced to construct a numerical model. The results indicate that the pyrolytic reaction begins at the junction of the heating wall and the side walls, and the main products of pyrolysis are light olefins and alkanes. The thermal cracking reaction slows down the velocity of the main flow on account of the increased density and increased viscosity resulting from the decrease in RP-3 temperature. With the decrease in inclination, thermal cracking is enhanced and the average heat transfer coefficient is decreased, which leads to an increase in wall temperature.

Thirty-Two Weeks of Oral Supplementation with LinPro™ Increases Hoof Growth in Healthy Mares

LinPro™ (LP) is a commercial dietary supplement marketed to increase hoof growth and quality. Ten mature (5-15 years) non-pregnant Quarter Horse mares without existing hoof quality issues were used to test the hypothesis that 32 weeks of daily supplementation with 113 g of LP would increase hoof growth rates as compared to non-supplemented controls. Hooves were trimmed at the start of the study and every 8 weeks thereafter. A mark was applied on the hoof wall surface at 2.5 cm below the junction of the hoof wall and coronary band. At each trimming, the distance between the mark and coronary band was measured and a new mark placed. For front hooves, horses assigned to LP had greater total hoof growth over 32 weeks (2.65 ± 0.15 vs. 2.18 ± 0.12 cm; P=.048) and tended to have greater hoof growth per 8 weeks trimming cycle (0.64 ± 0.03 vs. 0.55 ± 0.03 cm; P=.085) than horses assigned to non-supplemented controls (CON). Horses assigned to LP had greater plasma biotin concentrations (2158 ± 69 vs. 636 ± 62 ng/L; P < .001) and proportions of erucic acid in hoof tissue (1.03 ± 0.08 vs. 0.76 ± 0.07 %; P=.049) as compared to CON. Further, the most abundant fatty acids in hoof tissue were stearic, palmitic, oleic, and linoleic acids. LinPro may provide an effective treatment to improve hoof growth rates in horses with otherwise healthy hooves.

Experimental investigation on impact response of sandwich composites integrated with a novel 3D multi-layer stitched core

Impact damage resistance of the sandwich composites affects the structure reliability and crucially depends on the core. The weak junction of core unit-cell walls causes a catastrophic failure on sandwich composites under impact load. Stitching is an efficient and easy way to obtain the strengthened core unit-cells. In this study, the impact behavior of glass/epoxy face sandwich composites integrated with a novel 3D multi-layer stitched core were investigated. The peak forces and absorbed energy of sandwich composites were increased as the number of core layer increased. The increase in core layers and core dimensions caused more flexible sandwich composites. The core was more effective in the energy absorption mechanism of the sandwich composites than faces with the increased stitching density and decreased unit-cell size of core. The number of core layers, dimensions of core unit-cells and stitching density were found to be most important parameters for the impact failure of sandwich composites.

In-plane elasticity of the re-entrant auxetic hexagonal honeycomb with hollow-circle joint

This work proposed an improved modification on the common re-entrant hexagonal honeycomb (RHH) by replacing the solid junction of the cell walls with a small hollow circle, and thus achieving a novel kind of honeycomb. A simple energy-based approach was adopted to develop theoretical models for predicting the in-plane equivalent elastic moduli of the new honeycomb. Finite element analysis was employed to verify the theoretical models and then the effects of the micro geometrical parameters on the in-plane elastic behaviors were further discussed. The results showed that the new honeycomb possesses an obvious negative Poisson's ratio effect, meanwhile, can achieve higher specific Young's modulus and shear modulus than the RHH. Moreover, the new honeycomb was found to exhibit a more tailored anisotropy than the RHH from the off-axial properties analysis. As a result, the new honeycomb may be an effective substitute for the RHH in application and the new layout can be a good guide for the improved design of auxetic honeycombs.

Subaxial Cervical Pedicle Screw Placement With Direct Visualization of Pedicle Borders: 2-Dimensional Operative Video.

Pedicle screws provide superior fixation of the subaxial cervical spine to other techniques. However, a high degree of accuracy is required for safe placement given the proximity of pedicles to critical neurovascular structures. A variety of techniques are described to maximize accuracy, including freehand, fluoroscopy-guided, and neuronavigation-based methods. We present a technique for the placement of pedicle screws in the subaxial cervical spine using direct visualization of the pedicle in a patient who required an occipito-cervical fusion construct in the setting of a C2 chordoma. A laminotomy or laminectomy is performed laterally to allow for visualization of the medial, superior, and inferior walls of the pedicle. The entry point for screw placement is determined based on pedicle anatomy and is typically 1 to 2 mm lateral to the midpoint of the lateral mass, just below the base of the superior articulating process. Screw trajectory is determined by visualizing the pedicle borders and is aimed at the junction of the medial pedicle wall, with the posterior vertebral body down the pedicle axis. Tactile feedback (loss of resistance) is used to assess for a breach while drilling. The cannulation is then tapped, and the screw is placed in a standard fashion. Direct visualization of pedicle anatomy can be a useful adjunct to guide the safe placement of subaxial pedicle screws when superior fixation is required or when normal anatomy is distorted. The technique may be combined with fluoroscopic or navigation-based techniques to provide real-time anatomic guidance during screw placement. The patient provided informed, written consent for this procedure before surgery. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Unified approach on numerical implementation of heatfunction boundary conditions for accurate prediction of heatlines involving steady convection in enclosures

The tool “Heatlines” is useful to understand heat flow and thermal management in enclosures experiencing convection. The heatline concept was first introduced by Bejan in the early 80’s. This article starts with the fundamental principles of heatlines or heat flow trajectories followed by a generalized governing equation for heatfunction (Π) applicable for fluid, nanofluid, or fluid-saturated porous medium experiencing steady natural or mixed convection within enclosures. An unified approach on derivation of heatfunction boundary conditions is presented based on Dirichlet conditions at junction of walls while Neumann conditions at walls for Π. The solution of Π also requires the selection of location of Π = 0 and this article outlines a generalized overview on the invariance of heatline trajectories irrespective of the location of Π = 0 for enclosures with or without adiabatic walls. Open loop or end to end heatlines demonstrate the heat flow path for conductive heat transport whereas open loop heatlines cross various regimes of dominant conduction or convection zones connecting the hot walls to the cold walls for convective heat transport. Closed loop heatline vortices (qualitatively similar to the flow vortices) depict the convective heat flow via the trajectories of the fluid flow vortices. A few feasible heatlines for conduction and convection dominant heat transport in enclosures (steady state) have been presented to illustrate the physics of “heatlines.” This article also addresses a few earlier works depicting discrepancies in heatline trajectories [discrepancies: heat flow to and from the same walls (isothermally hot/cold or adiabatic) or heat flow from the hot/cold to the adiabatic wall(s)] and proposes qualitative pictures for feasible heatlines for a few earlier case studies. Understanding the feasible implementation of heatlines is required as the inaccurate representation of heatlines may mislead future researchers in interpreting the energy flow.

Verification of the junctional dose for irradiation of the chest wall and supraclavicular regions under the circumstances of advanced technologies.

A single-isocenter half-beam technique is commonly used when irradiating the chest wall and supraclavicular regions in patients with high-risk breast cancer. However, several studies have reported that underdosage can occur at the junction of the chest wall and supraclavicular regions due to a "tongue-and-groove" effect. This study verified the efficacy of an open leaf technique (OL-tech) that involves placing a multileaf collimator 5 mm outside from the beam central axis to remove the effect of the multileaf collimator in a single-isocenter half-beam technique. We compared the junction doses of the OL-tech with those of a conventional technique (C-tech) in square and clinical plans, using 4 and 10 MV x-rays in the Clinac iX and 6 and 10 MV x-rays in the Trilogy accelerators (Varian Medical Systems, Palo Alto, CA). EBT3 radiochromic films were used for measurements. Measurements were performed at a depth of 3 cm when verifying field matching. The EBT3 films in the square plan indicated junction doses for the C-tech of 78.3% with the Clinac iX accelerator and 73.6% with the Trilogy accelerator. By contrast, the corresponding doses for the OL-tech were 107.2% and 99.8%, respectively. In the clinical plan, the junction doses for the C-tech were 76.5% with the Clinac iX accelerator and 72.6% with the Trilogy accelerator; the corresponding doses for the OL-tech were 108.3% and 101.7%, respectively. As with the square plan, variations in the junction dose were much smaller using the OL-tech than using the C-tech. Our results suggest that the OL-tech can be useful for improving dose homogeneity at the junction of the chest wall and supraclavicular regions.

Stress distribution and deformation in six tie wings Orthodontic bracket during simulated tipping – A finite element analysis

Background and ObjectivesFour tie wings brackets are widely used in orthodontics, while the Six Tie Wings Brackets (STWB) are recently emerging in fixed orthodontic appliances due to their claim for less friction and thus faster teeth movement. The aim of this work was to evaluate the stress distribution and deformation during simulated mesio-distal tipping forces in Stainless Steel (SS) six tie wings orthodontic bracket using Finite Element Analysis (FEA). MethodsA six tie wings bracket (Synergy®, RMO, USA) dimensions were measured using the Vision system and a 3D model of the bracket was constructed. A Finite Element (FE) model was developed and mesio-distal tipping forces of 1.22 N to 1.96 N (125 to 200 gm) in increments were applied on the gingival and incisal slot walls. The stress distribution and deformation were recorded at specific points in the bracket and analyzed. ResultsThe maximum deformation and stress distribution for the mesial and distal tipping forces of 1.96 N were recorded as 0.137 µm and 10.60 MPa respectively. The stress concentration was more at the junction of the slot wall and the slot base. For mesial tipping,the deformation was more on the disto-incisal and mesio-gingival tie wings. Similarly, for distal tipping the deformation was more on the mesio-incisal and disto-gingival tie wings. The mid-tie wings showed minimal deformation during both distal and mesial tipping. ConclusionsOur study visualized both the mesial and distal tipping forces induced stress distribution in the bracket tie wing-slot junctions. The deformation was present maximum in the mesio-incisal and disto-incisal tie wings and minimal in the mid-tie wings. Clinicians should be aware of this behavior of STWB in making decisions to alter the tipping forces in the archwire to compensate for the tie wing deformation in refining the teeth position.

Construction of 6061-T6 aluminum alloy constitutive model based on hot bulging test and study on the non-isothermal hydroforming process

Due to the high requirements of drawing equipment and process, it is relatively rare in the field of aluminum alloy sheet forming to introduce soft or sticky fluid medias as soft mold into the course of hydroforming with a non-isothermal condition that maintaining the temperature of high pressure liquid differs to the ones of molds. Consequently, in this paper, the material stress-strain curve in the temperature range is obtained by the bidirectional tensile hot bulging test which contains compress to sheet’s thickness, and can best meet the characteristics of non-isothermal hydroforming in mechanics compared with unidirectional hot stretching. Based on analysis of stress-strain of 6061-T6 aluminum alloy, its constitutive equation on the basis of an original model of processing hardening rate is established for finite elements numerical simulation, and a highly accurate setting range of forming temperature can be confirmed to provide guidance for practical manufacturing accordingly. Result of the study suggests, by applying the constitutive model mentioned above, simulation on non-isothermal hydroforming can reach a desirable effect; The non-isothermal condition set reasonably causes an enhance to the junction of straight wall and round corner, and a deduce of thickness reduction rate simultaneously, limit height increases as a result. Besides, the fluency of blank located in the flange improves to a great extent when its temperature is well set. The position of the 1 mm wall thickness constant line of the workpiece is further reduced, so that the forming quality of the workpiece is remarkably improved.

Evaluation of stent-graft implantations for intramural hematoma based on fluid-solid interaction analysis

Endovascular stent-graft (SG) repair for patients with intramural hematoma (IMH) requires suitable SG deployment to avoid complications. In this paper, several SG implantation schemes are quantitatively evaluated by CFD tool, in which the mutual interactions between blood, SG and arterial wall are taken into account. Factors considered: (i) the depth d of SG implantation into the vascular wall; (ii) the deployment length L (exceeding O% of the lesion); (iii) the material of SG; (iv) the shape of SG. The total deformation, Von-Mises stress and wall shear stress (WSS) on arterial wall and stent are analyzed, and particularly the related fitting curves are displayed. The results show that the Von-Mises stress exerted on IMH wall increases with the increment in d or decrement in L, with remarkable variations at about d ∈ [0.2,0.4] or L ∈ [33.3%,60%]. The stress for IMH wall is linear inverse correlation with SG stiffness, and the stress discrepancy among different SGs is up to 37.6%. The Von-Mises stressmax for arterial wall and stent appears at the junction of healthy and IMH walls and the region where the SG curvature changes the most, respectively. Further, although the fluctuation of WSS is smaller than that of Von-Mises stress, the WSS remains linearly increasing with the decrement of L, d and material stiffness. Results obtained can potentially serve as the guideline to SG surgery for IMH patients.

A fractal-skeleton model of high porosity macroporous aluminum and its heat transfer characterizes

Macroporous metal foams are used as energy exchange materials and have been widely used in the industry. In this paper, the finite element method is used to calculate the equivalent thermal radiation conductivity and equivalent thermal conduction equivalent conductivity of the fractal-skeleton heat transfer model, and the heat transfer characteristics of the two components are analyzed. The results show that during thermal conduction progress, energy transfer mainly occurs at the junction of walls and holes perpendicular to the direction of heat flow. While during the thermal radiation process, the smaller the cell wall thickness and the larger the porosity, the larger the proportion of the heat radiation conductivity in the total heat conductivity. When the structural size is equal to the characteristic wavelength, the scattering coefficient is rapidly reduced, so that the radiation heat transfer effect is improved. Finally, the cause of this phenomenon is further explained by the micro-mechanism theory.