Side Of Plate Research Articles

Experimental and numerical investigation of the damage characteristics of a ship side plate laterally punched by a scaled raked bow indenter

Experimental and numerical simulation studies are conducted on a scaled ship side-shell quasi-statically punched at the mid-span by a raked bow indenter to investigate its damage characteristics from deformation to a large opening. A scaled stiffened panel and a raked bow indenter are designed in model tests. Numerical simulation is performed to simulate the indentation responses. The experimental and numerical results are compared well in terms of resistance-penetration curves, final damage shapes and especially the three failure models, i.e., initial fracture, model “I” crack and model “III” crack. In addition, the whole damage process, the energy dissipation characteristics of the specimen and failure related parameters in three specific failed elements corresponding to the three failure models are analyzed through numerical simulation. The results demonstrate that the energy dissipated by the stiffener and frictional effect is substantial during the crack propagation process. In addition, shell elements involved with three failure models prior to fracture are mainly subjected to tension and bending effects, as shell elements cannot satisfactorily simulate the transverse shear effect. Finally, the influences of collision parameters, the failure sequence of integration points, modeling of weld seams, mesh resolution and failure criteria on the numerical simulation results are discussed.

A new small thecate dinoflagellate Azadinium anteroporum sp. nov. (Amphidomataceae, Dinophyceae) isolated from the Asian Pacific

ABSTRACT The marine thecate dinoflagellate Azadinium includes species known to produce the diarrhetic shellfish toxins known as azaspiracids (AZAs). In this study, the morphology of a thecate dinoflagellate isolated from Mutsu Bay, Japan, was examined by LM and SEM, and its phylogenetic position was inferred from ITS and LSU rDNA sequences. The production of AZAs was examined by liquid chromatography-triple quadrupole mass spectrometer (LC-MS/MS). Cells were elliptical, 15.9–22.4 µm long and 11.1–17.1 µm wide. A chloroplast was positioned peripherally, with a pyrenoid near the cingulum, and the nucleus was placed in the hyposome. The hyposome was smaller than the episome, with an antapical spine on plate 2''''. Thecal tabulation was Po, cp, X, 4', 3a, 6'', 6C, 5S, 6''', 2''''. The apical pore complex consisted of a symmetrical apical pore plate (Po), a cover plate (cp) and a small canal plate (X), and was surrounded by a prominent collar formed by the apical plates. A ventral pore was located on the mid-anterior edge of plate 1' and contacted with the X-plate and/or the ventral left of plate Po. Plate 1'' was in contact with plate 1a. AZA was not detected in the cultures. Molecular phylogeny showed that the species was related to Azadinium species that possess the ventral pore on the left side of plate 1', i.e. A. cuneatum, A. dalianense, A. obesum, A. poporum, A. spinosum and A. trinitatum, but that it was not included in these species. The new species Azadinium anteroporum sp. nov. differs in the ventral pore position (mid-anterior edge of plate 1') from these related species (which have the ventral pore on the left side of plate 1'), and from A. polongum (with ventral pore on the posterior left side of 1') and all other Azadinium species (with ventral pore on the right side of 1').

Deformation Analysis of Novel Sorbite Stainless Steel-Aluminum Alloy Attached Lifting Protection Platform

The all-steel attached lifting protection platform widely employed in recent years has always suffered from self-weight issues and corrosion. Aluminum alloy is the ideal option for steel owing to its low bulk density and resistance to corrosion and rust. However, its elastic modulus is insufficient, causing the deformation of the structure to easily exceed the limitation of the Code for Design of Aluminum Alloy Structures. Therefore, this study recommended using sorbite stainless steel with high strength and a reasonable price as the guide rail of a protection platform having a significant force in conjunction with aluminum alloy to maximize their advantages. Regarding the overall structure, Midas GEN was used to verify whether their deformation adheres to the specifications. For exploring the stiffness of exact nodes, the wall-attached support was modeled by Abaqus, discovering that its maximum composite deformation is 0.725 mm, and its highest stress (490.2 MPa) appears at the intersection of the bottom and the side plate. Additionally, the influence of three key factors (the cantilever height of the protection platform, the horizontal spacing between two wall-attached supports, and the sectional size of the main frame fittings) on the structural deformation was investigated. Finally, the cost per extension meter was compared between the all-steel and the novel sorbite stainless steel-aluminum alloy attached lifting protection platform. The findings of the aforementioned works can effectively guide the design and construction of this novel structure and play a crucial role in its popularization and application.

Investigation of column-to-base connections of pole-mounted solar panel structures

This study investigated the load-carrying capacity of solar panel structures focusing on the column-to-base connection of pole-mounted structural systems using full-scale testing and numerical simulations considering the connection details as a key variable. The aim was to develop a non-welding connection detail for improved durability. For the connection details, a total of 10 plinths with base plates and supporting plate units were developed. The plinths with supporting plate units included two different bolt layouts at the column and base connections. The experimental results indicated that most specimens had sufficient load-carrying capacity to withstand the calculated yielding force even for the non-welding connections with supporting plate units. The failure modes observed in the experiments included cracking in the welded region, local buckling of the column, and bolt tear-out. The numerical simulations demonstrated that the details of the connection, such as the shape of the side plates, use of rib plates, and bolt layout, affected the structural performance. In addition, it was found that some specimens had strong and weak axes, depending on the orientation and shape of the side plates. Therefore, the details of the column–base connections of pole-mounted solar panel structures should be carefully designed based on proper structural evaluation of the connection details.

The Study of Selected Aspects of the Suborbital Vehicle Return Flight Trajectory

The article presents the results of preliminary studies of the parameters of the return flight trajectory of a rocket plane for suborbital tourist flights into space. The rocket plane is designed as a tailless vehicle and has an unconventional arrangement of control surfaces: elevons and side plates that can rotate. The main aim of the research presented in this paper is to investigate the dynamic stability of the rocket plane and the response to control in the return suborbital flight. The secondary objective is to study the behavior of the rocket plane with respect to the initial state of the return flight. The key parameters taken into account in this study are the Mach number and G-load. Moreover, a study of the trim condition, dynamic stability and response to control of a rocket plane in the low part of the stratosphere is presented. The tests were carried out using a numerical simulation of the flight of a rocket plane. Dynamic stability was determined on the basis of time history analysis, and the results were compared with the results obtained by solving the eigenvalues problem. The results revealed that the rocket plane should be equipped with a Stability Augmentation System to improve short period damping at supersonic speeds at moderate altitudes. It can also be concluded that the maximum load G and Ma do not occur at the same height of flight. In terms of the effectiveness of the control surfaces, they start working at an altitude of 55 km. Due to the speed regime, the obtained results can be useful in the design of such objects as rocket planes, highly maneuverable and supersonic aircraft.

First Report of Colletotrichum theobromicola Causing Anthracnose on Euonymus japonicus in China.

Euonymus japonicus, a broad-leaved evergreen tree, is widely planted in the parks and landscapes in the world (Huang et al. 2016). In 2019, anthracnose lesions were found on leaves of E. japonicus with 4~15% incidence from the Wufulinglong park (116°28' E, 39°94' N) in the Haidian District of Beijing, China. Irregular chlorotic spots appeared on the surface of the leaves, then larger necrotic spots with numerous acervuli gradually formed, and finally the infected leaves dried and dropped, detracting from the aesthetic of the landscape. To identify the pathogen, six representative leaves with typical symptoms in Wufulinglong park from three plants were collected and diseased tissue was cut into 2 mm × 2 mm pieces, disinfested in 75% ethanol for 20 s, rinsed twice in sterile water, plated onto potato dextrose agar (PDA), which were then incubated at 25℃ under 12 h photoperiod. A total of 24 morphologically identical isolates were obtained from the samples. Two of these isolates were randomly selected for further analysis to confirm their identity. The cultures (HDwfll1907HY and HDwfll1908HY) were deposited in the culture collection of the Beijing Academy of Agriculture and Forestry Sciences, China. Furthermore, genomic DNA was extracted and the sequences of internal transcribed spacer (ITS) regions, calmodulin (CAL), beta tubulin (TUB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT) and chitin synthase (CHS) were amplified using the primers ITS1/ITS4 (Gardes et al. 1993, White et al. 1990), CL1C/CL2C (Weir et al. 2012), T1/Bt2b (Glass et al. 1995, O'Donnell et al. 1997), GDF1/GDR1 (Guerber et al. 2003), ACT-512F/783R and CHS-79F/345R (Carbone et al. 1999), respectively. Newly obtained sequences were deposited into GenBank with accession numbers MZ229612~13 and MZ305422~31. Phylogenetic tree based on the assessed gene loci revealed that both strains clustered closely with C. theobromicola. The strain HDwfll1907HY was randomly selected for morphological description and pathogenicity assay. The colony was initially light gray with dense aerial mycelia on PDA, which later turn to gray with grayish green on the reverse side of plates. Conidiogenous cells were cylindrical, arising from swollen hyphae. Conidia were single-celled, hyaline, subcylindrical to clavate, often with broadly rounded ends, 13.78-21.99×3.47-5.44 µm (n=50). Both phylogenetic analysis and morphology support the identification of two strains as C. theobromicola. Pathogenicity tests were performed on three healthy one-year-old E. japonicus plants using the randomly selected isolate HDwfll1907HY. The leaves were sprayed with 20 mL of conidial suspension (107 conidia/mL), sterilized water inoculation under the same condition was used as control. All the treated plants were incubated in the incubator at 25°C and 90% relative humidity under 12 h photoperiod. After 18 d, all the leaves treated with the conidial suspension showed typical symptoms of anthracnose, similar to those in the field, whereas the control leaves remained symptomless. The disease assay was replicated three times for consistency. The same fungus was reisolated from the infected leaves and identified as C. theobromicola. This is the first report of C. theobromicola causing anthracnose on E. japonicus, which provides the foundation for the management of anthracnose on E. japonicus.

Model for calculating local bearing capacity of concrete with spiral stirrups

This study evaluates the mechanical and failure modes of 30 concrete specimens under local compression. The experimental results indicate that the specimens undergo three types of local compressive failure modes. These modes primarily depend on the strengths of the tensile and compression regions. Based on the test results, a calculation model for the local bearing capacity of concrete with spiral stirrups Fl is formulated. In the model, the local compressive failure of concrete with spiral stirrups is classified into tension and compression. The yielding of spiral stirrups in the tensile region is regarded as tensile failure, and compressive failure is considered to have occurred when the strain value in the compression region reaches 0.002. To simplify the model calculation, the spacing s, diameter d, and yield strength fy of spiral stirrup as well as the local compression area ratio Ab/Al (ratio of the concrete bearing area Ab to the loading area Al) are comprehensively analyzed. Based on the analysis results, a formula for the bearing capacity of the reinforcement Ns is derived. The independent variables of the formula are yield force of spiral stirrup fyAssl, stirrup spacing s, and ratio of specimen side length to loading plate side length h/a. A simplified formula for calculating the tensile failure of the specimen is derived. To ensure simultaneous tensile and compressive failures, a critical reinforcement ratio of the spiral stirrup ρvu is proposed based on the calculation model. Test data from similar axial local compression tests are collected to verify the accuracy of the calculation model. The local bearing capacity of concrete is recalculated according to the calculation method proposed in this study. Results show that the calculation model is highly accurate. Accordingly, it may be used as reference for calculating the local bearing capacity.

Investigating the buckling deformation of thin metal sheets during the blanking process

This article describes the effect of the generated stresses due to the cutting process on the possibility of the occurrence of buckling deformation in a thin sheet, which could affect the performance of the cut part, especially for some applications such as the cutting of the thin sheet laminations of motor parts. To achieve the research objectives, an experimental approach was followed. Two different thicknesses and two-grain orientations of silicon steel material were applied to investigate the influence of thickness and grain orientation upon the induced buckling deformation. Blanking dies were designed to cut thin sheets of steel at different cutting speeds. Buckling height was measured optically using a 3D microscope with regard to the cutting parameters. The results showed the appearance of buckling deformation only at low sheet thickness. The maximum buckling height was about 164 µm (82% of the material thickness) in the transverse grain direction at the lower cutting speed. Meanwhile, the results also demonstrated the presence of an elongation in the material of approximately 90 µm (1.8%) on the cutting sides, which played a role in the application of pressure to all sides of the cut plate, resulting in the formation of a plastic buckling deformation prior to the completion of the cutting process, and thus the occurrence of the buckling phenomenon.

A novel thrust vector nozzle with conical surface based on Coanda effect

In this paper, a novel thrust vector control method based on Coanda effect is proposed for conical surface. The effect of thrust vector control is studied by computation fluid dynamic (CFD) numerical simulation. When there is no side plate on both sides of Coanda surface, there are large vortex structures on both sides of nozzle wake, and the vector control cannot be realized. After adding the side plate, the comprehensive control of the pitch and yaw thrust vectors was realized. When the nozzle pressure ratio (NPR) is 2~2.4, the pitch and yaw vector angles decreased with the increase of NPR, and the maximum pitch vector angle is 8°. And the yaw vector angle is 8°.

REDUCTION OF CRACK FORMATION DURING ABRASIVE TREATMENT WITH DIAMOND PASTES OF SILICON CARBIDE SEMICONDUCTOR PLATES

The results of diamond-abrasive treatment of the reverse side of silicon carbide semiconductor plates of polytypes 4H and 6H are presented. Dimensions of surface microcracks of ceramic plates after abrasive treatment with pastes with diamond powder of different grain size are investigated, and also relationship between length of surface microcrack and rate of material removal depending on technological modes of diamond-abrasive treatment is established. As a result, a new method of single-sided abrasion treatment of thin ceramic plates is proposed, which ensures reduction of crack formation.

Controlling the light diffraction through a single subwavelength metallic slit via phase gradient

In this work, we show that the concept of phase gradient metasurfaces provides a versatile way to control the diffraction of light through small holes or slits. As an example, we consider a single subwavelength metallic slit surrounded by air grooves of gradient depth that induces the expected phase gradient. It is found that for normal incident light, the phase gradient can enable unidirectional excitation of surface plasmons, which flow directionally toward the slit, resulting in extraordinary optical transmission beyond that in conventional ways. Using this scheme, unidirectional radiation of an optical dipole located inside the slit can be obtained when different phase gradients are applied to both sides of the metal plate.

New specimens of Cyclocystoides scammaphoris (Echinodermata) from the Upper Ordovician rocks of the American midcontinent with implications for cyclocystoid functional morphology

AbstractNew specimens of Cyclocystoides scammaphoris Smith and Paul, 1982, are here reported from the Upper Ordovician Platteville Formation of northern Illinois, Plattin and Decorah groups of east-central Missouri, and Lebanon Limestone of central Tennessee. These fossils reveal skeletal details that provide insight into the anatomy of cyclocystoids. Of particular significance is a network of channels that likely originate near the center of the central disk and extend along the oral side of the radial plates, bifurcating distally two or three times before entering the radial facets on the proximal surface of each marginal ossicle. From here, the network enters a series of facet canals that extend upward through each marginal ossicle, exiting in a linear row of pores. The canals are very similar in size and distribution to the nerve canals in living echinoderms. The axes of the canals, which number up to 500 in some specimens, and those of the radial ducts project proximally away from the oral surface at an elevation angle of about 25°, apparently forming a network that could have converged within the upper part of the body cavity. This origin and function are made clear by the connection between the channel on each radial plate and the radial facet canal pores within each marginal ossicle.

First Report of Anthracnose Crown Rot on Strawberry (Fragaria × ananassa Duch.) Caused by Colletotrichum pandanicola in Yunnan Provence, China.

Strawberry (Fragaria × ananassa Duch.), a widely grown octoploid species, is one of the most important economic fruit crops and has been widely cultivated in the world, including China. In December 2021, a serious crown rot disease (approximately 50% incidence) was observed in strawberry (cultivar Miaoxiang) plantations in Qujing City, Yunnan Province, China. Symptoms observed on aboveground part withered rapidly, reddish-brown marbled necrosis on crown. The roots were healthy and strong, but the plants finally died. To isolate the causal agent of this disease, crown tissues from five strawberry plants showing typical symptoms were cut into pieces of 5×5 mm, and the pieces were surface-sterilized with 75% ethanol for 45 s followed by 2.5% NaClO for 3 min and rinsed thrice with sterile water, and then placed onto potato dextrose agar (PDA) for 7 days at 25 ºC. After 3 to 4 days, extended single hyphal tips from the tissues were transferred to PDA and incubated for 7 days at 25 ºC. The colonies were initially white, later became somewhat zonate, velvety, cyan gray on the upper side and cyan ink pigment ring on the reverse side of plates, with concentric rings of salmon sporodochia. Many yellowish or orange creamy conidial droplets formed on PDA after 14 days at 25 ºC. Fifty-nine isolates were obtained, and three isolates QLYRR1, QLMCR9, and QLMCR39 were selected for further experiments. Conidia were hyaline, cylindrical with rounded ends, 12.17-19.35×3.71-6.30 μm (average±SD, 15.24±1.37×5.09±0.45 μm, n=150), L/W ratio = 2.99. The three isolates were molecularly identified using the genomic regions of internal transcribed spacer (ITS), actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-tubulin (TUB2) genes, and the sequences were deposited in GenBank (accession nos. QLYRR1, QLMCR9, QLMCR39: ON668272, ON668256, ON668257[ITS], ON684302, ON684300, ON684301[ACT], ON684316, ON684314, ON684315[CHS-1], ON684292, ON684290, ON684291[GAPDH], ON684286, ON684284, ON684285[TUB2]). The phylogenetic analysis of experimental strains was performed by Maximum-likelihood (ML) tree and Bayesian inference (BI) method. Nucleotide sequences exhibited three isolates were clustered with the ex-type strain C. pandanicola strain MFLUCC 170571T found in Thailand, C. pandanicola strains (SAUCC201152, SAUCC200204) found in Shandong Province, and the holotype stain C. parvisporum YMF 1.06942T found in Guangxi Province, China. Morphologically, isolates were easily distinguished from C. parvisporum by the colony on PDA and the size of conidia (Yu et al. 2022). Morphological characteristics and phylogenetic analyses revealed that QLYRR1, QLMCR9, and QLMCR39 belong to C. pandanicola, the members of the C. gloeosporioides species complex (Tibpromma et al. 2018; Mu et al. 2021). Koch's postulates were tested by strawberry plants (two cultivars, Akihime and Miaoxiang) in vivo, strawberry plants were tested for the three isolates by spraying 1×106 conidia/mL suspension on three seedlings. Three seedlings sprayed with sterile distilled water were served as control. All of the plants were transferred to a glasshouse with a 28/20 °C day/night temperature range and natural sunlight. After 6 weeks, QLYRR1-, QLMCR9-, and QLMCR39-sprayed seedlings were stunted and developed typical wilt symptoms similar to those observed in the field with the incidence for 3, 3, and 3 seedlings, respectively. The negative control remained asymptomatic. The fungi were reisolated again from lesions of diseased plants and leaves with 100% frequency, and morphological characteristics and tested gene sequences were identical to the original isolates in this note, thus fulfilling Koch's postulates. C. pandanicola was described from the healthy leaves of Pandanus sp. and the lesion fruits of Juglans regia. To our knowledge, this is the first report confirming C. pandanicola causes anthracnose crown rot on strawberries in China. C. pandanicola has the potential for causing serious losses to the strawberry industry, and research is needed on management strategies to minimize losses.

Comparison of functional outcomes of pertrochanteric fractures of the femur managed with dynamic hip screw with a locking side plate versus proximal femoral nail

Background: In current practice, proximal femoral nail (PFN) and dynamic hip screw (DHS) with locking side plate are the implant of choice in stable trochanteric fractures. Most of the deficiencies of the standard DHS have been addressed by the introduction of the Locking side plate. There are plenty of studies comparing standard DHS and PFN. But studies comparing locking DHS and PFN are scarce in current literature. This study aimed to compare the outcomes of both implants in stable pertrochanteric fractures. Methods: The objective of this study was to assess and compare the clinical outcomes of using locking DHS and PFN for fixation in 40 patients who were admitted to SUT Academy of Medical Sciences between October 2017 and April 2019. The modified Harris hip score was used to evaluate the patients' progress, and regular follow-up was conducted to compare their outcomes. Results: Among the DHS group, the mean Harris hip score was 83.05, with excellent results observed in 2 patients (10%), good results in 12 patients (60%), fair results in 5 patients (25%), and poor results in 1 patient (5%). In comparison, the PFN group had a mean Harris hip score of 85.50, with excellent results seen in 6 patients (30%), good results in 10 patients (50%), fair results in 3 patients (5%), and poor results in 1 patient (5%). Conclusions: The DHS group had more patients with good and fair outcomes, while the PFN group had more patients with excellent and good outcomes. Based on these findings, we can conclude that both the PFN and DHS with locking side plate are similarly effective in treating stable intertrochanteric fractures.

Effect of Al or Ti addition on the ferrite formation in ultra-low oxygen weld metal of low carbon steel

Effect of Al or Ti addition on the ferrite formation in ultra-low oxygen (about a few tens ppm) weld metal of low carbon steels were investigated. A bead-on-plate welding experiments were performed with a Tungsten Inert Gas (TIG) welding system. The double nozzle was attached to the welding torch used, Ar was passed along the outer nozzle and He is added along the inner nozzle. Optical micrographs showed that primary ferrite appeared along prior austenite grain boundaries and that as the temperature is decreased ferrite side plates were grew into grain interior. Their formation positions were approached to the welding end as the decreasing Al and increasing Ti content. This change in ferrite formation position attributed on the ferrite formation temperature, which was assumed to increase as the decreasing Al and increasing Ti content. Energy dispersive X-ray spectroscopy analysis of inclusions showed that Al and Ti were mainly associated with 0, it was obvious that the inclusions in the steels were Al- and Ti- oxide inclusions. Al-oxide inclusions were not favourable acicular ferrite nucleation sites and the inclusions contributing to acicular ferrite formation were Ti-oxide ones. The number density of acicular ferrite was small. This indicated that acicular ferrite formation was suppressed because the number density of inclusions was low under the ultra-low oxygen welding condition.

Finite element analysis of tooth movement under different retraction force and intrusive force in double-archwire lingual orthodontics system

The objectives of this study were to evaluate the tooth movement tendency during space closure in maxillary anterior teeth by various combinations of retraction force and intrusive force in a double-archwire lingual orthodontic system. Mini-implant-double slot lingual orthodontics system models of the bilateral maxillary first premolar extraction cases were constructed. Three-dimensional finite element models of the maxilla were constructed with definite position mini-implants (8 mm) and power arms (6 mm). Different retraction forces(50gf、100gf、150gf)were applied with the help of a nickel-titanium closed coil spring on the plate side. Intrusive forces(0gf、50gf、100gf)were applied with the help of the mini-implant between the two central incisors, and the initial displacements of the maxillary anterior teeth were analyzed. Variable amounts of displacements like controlled tipping, uncontrolled tipping, lingual crown tipping, labial root tipping, extrusion and distal crown tipping were observed in all the models, and these tendencies increased as the magnitude of retraction force increased, and these tendencies decreased as the magnitude of intrusive force increased. When the intrusive force was greater than or equal to the retraction force, the maxillary central incisors showed the trend of lingual crown tipping and labial root tipping, resulting in uncontrolled tipping movement. In terms of horizontal changes, the increasing width of bilateral anterior teeth was observed, with canines showing the least increasing trend. Various combinations of retraction force and intrusive force in a double-archwire lingual orthodontic system provide a new choice for torque control of the anterior teeth. Although anterior mini-implants and elastics can achieve incisor intrusion and lingual root torque, they cannot achieve the expected torque without additional torque control methods.

Research on welding deformation of hollow thin-walled complex structural parts based on plane bending theory of constant section beam

In order to effectively forecast the welding deformation and deformation pattern of hollow thin-walled aluminum alloy complicated structural parts, based on the plane deformation theory of constant section beam and workpiece constraint conditions, the complex feature structure was split and the deflection curve equation of each position was constructed. Moreover, the inherent strain method was used to solve the welding equivalent load, and the welding deformation was calculated by combining the equivalent load with the deflection curve equation. On the basis of the theoretical load value, the welding deformation at different positions during and after welding was numerically simulated by finite element simulation. What's more, the theoretical deformation of each plate is verified by the simulated deformation results. Besides, the simulation deformation results of post welding deformation are verified by welding experiment. The results show that the shrinkage deformation of the welding position is the largest, the transverse and longitudinal deformation are 0.007 mm and 0.018 mm respectively, the error rates of theory and simulation are 5.2 % and 5.5 % respectively. What's more, the welding deformation at the non-welding position is mainly reflected in the vertical direction of the upper skin plate. After the external constraints are released, the actual maximal deformation values of the two sides of the upper skin plate are 0.08 mm and 0.064 mm respectively. The deformation presents an M-shaped distribution, which is comparable to the deformation distributions of theory and simulation. The deformation value caused by the welding process accounts for 10 % of the total deformation after the removal of external constraints. In addition, the welding process is the main stage of forming the deformation distributions at each position, and the release of external constraints is the main factor leading to the final deformation.

Defect modes and localisation of quasi-Lamb waves along a sidewall of corrugated aluminium plates

This study presents an observation of quasi-Lamb wave (QLW) localisation in a periodically corrugated plate with defects. The QLWs are excited and detected on one side of aluminium plates that are periodically grooved on the upper and lower planes with a strip defect. The periodic grooves result in the frequency forbidden band, whereas the defect is responsible for the additional transmission in this band. The QLW-amplitude measurements along the aluminium plates exhibit the transmission spectra of the defect modes as well as the QLW localisation near the middle strip. The numerical and experimental results confirm the additional transmission of the QLW defect mode and its frequency shifting. As the defect length increases, the transmission peak moves from the upper to the lower edges of the forbidden band. Furthermore, the calculated dispersion curves of the QLWs break at the frequency of the forbidden bands, and a localised mode appears in the middle when the defect length is nonzero. The experimentally observed QLW defect modes in elastic plates not only enrich our knowledge on the interaction between elastic waves and structures but also significantly benefit related engineering applications, such as ultrasonic non-destructive evaluation, elastic-wave filtering, and undersea acoustic-signal enhancement.

Pressure drop and friction factor study for an airfoil-fin printed circuit heat exchanger using experimental and numerical techniques

The airfoil-fin, Printed Circuit Heat Exchanger (PCHE) has been considered to be a key candidate for nuclear energy, Concentrated Solar Power, and several power conversion cycle applications, using different heat transfer fluids like molten salts, supercritical-CO2, and helium gas among others. In this study, differential pressure and flow rate measurements have been experimentally conducted across several axial spans on the hot side plate of an airfoil-fin PCHE. These experimental investigations have been performed across a wide range of Reynolds numbers (Re = 2,000–25,000), on a fully modular test rig, which utilizes additive manufacturing techniques. Furthermore, Reynolds-Averaged Navier–Stokes simulations have been performed, where the experimental work has been used to identify the boundary conditions. The numerical simulations have been used to predict the pressure drop and characterize friction factor correlations across an extended range of Reynolds numbers (Re = 100–100,000), and have been found to be in good agreement with the experimental investigations. These numerical simulations can be used to study the velocity and pressure fields in an airfoil-fin micro-channel geometry. Additionally, they can also be used to study the correlation between friction factor and Reynolds number across different flow regimes, that lays the foundation for future heat exchanger design studies.

Thermal analysis and optimization of the new ICRH antenna Faraday Screen in EAST

In Experimental Advanced Superconducting Tokamak (EAST) experiments, to achieve long pulse and high-power ICRH system operation, a new kind of ICRH antenna has been designed. One of the most critical factors in limiting the operation of long pulse and high power is the intense heat load in the front face of the ICRH antenna, especially the Faraday Screen (FS). Therefore, the cooling channels of FS need to be designed. According to thermal-hydraulic analysis, the FS tubes are divided into several groups to achieve more excellent water cooling capability. The number of series and parallel tubes in one group is chosen as six. This antenna went into service in the spring of 2021, and it is delightful that the temperature distribution of the FS tube is below 400 °C in 14.5 s and 1.8 MW ICRH system operation. However, the active water-cooling design was not carried out on the upper and lower plates of FS, which led to severe ablations on that region under long pulse and high power operation, and the temperature is up to 800. Therefore, the upper and lower side plates of the FS were designed with water cooling based on thermal-hydraulic analysis. During the 2022 winter experiments, the temperature of ICRH antenna FS was lower than 400 in the pulse of 200s and the power of 1 MW operation.