Side Of Plate Research Articles

Enhanced Performance of Structurally Optimized Plate-Fin Heat Exchangers Through Numerical Modeling of Heat Transfer and Pressure Drop

This study aims to optimize the structure of compact Plate-Fin Heat Exchangers (PFHE) by incorporating corrugated fins and validating their improved performance through numerical modeling and simulation. The results provide valuable insights for refining application-specific design guidelines and enhancing the performance of PFHEs. Using Computational Fluid Dynamics (CFD), the PFHE geometry was created in SolidWorks and Ansys Fluent, with fins modeled in three layers inside the heat exchanger both with and without a cover. To investigate the fins' performance, flow field, and heat transfer, fin thickness, entry velocities, and locations of water and air were varied across three wavelengths (10, 20, and 30) during the numerical investigation. The analysis focused on the variations in pressure, temperature, and fluid velocity within the heat exchanger. Key findings include the observation that temperature distribution is influenced by the velocities of both water and air, with the upper layer experiencing a temperature increase due to the warm fluid stream, while the opposite effect is observed near the bottom layer. Furthermore, fluid temperature variation in the depth direction is attributed to conductive heat transfer through side plates and convective heat transfer to the surroundings. The outcomes of this study have the potential to reduce the pressure difference generated during heat exchange and increase the thermal efficiency of PFHEs.

Determining the maximum turning force of the hydraulic backhoe excavator bucket

Introduction. Single-bucket excavators with both flexible and rigid suspension of work equipment are actively engaged in construction, stripping work and production mining. Excavators with rigid suspension are commonly used in construction, while excavators with flexible suspension are used in mining practice. This work considers the process of excavating rock with a single-bucket hydraulic backhoe excavator. The reliability and durability of excavators depend on the correct choice of the parameters of work equipment elements. Research objective is to determine the maximum turning force of the bucket of a hydraulic backhoe excavator, taking into account soil friction against the bucket bottom and side plates during rock excavation. Methods of research. When the maximum force on the bucket turning hydraulic-cylinder rods in the course of rock excavation is analytically defined, it is advisable to consider digging a trench in plain surface or in the open-pit in plain surface of a stope face provided that per one turn the bucket is filled to capacity. In this case, a segment of soil cut from the rock mass has maximum depth of cut as compared to other excavation methods. Total excavation resistance includes: resistance arising from cutting rock with a bucket with maximum depth of cut; resistance associated with the impact of gravity of the rock mass on the bucket; resistance associated with rock mass friction against the bucket bottom; resistance associated with rock mass friction against the inner surfaces of the bucket side plates. Results. The dependence has been determined between the maximum force on the bucket turning hydraulic-cylinder rods and bucket design parameters as well as the physical and mechanical characteristics of the face rock. The results analysis showed that both excavation process flow scheme and rock characteristics have a significant influence on the total bucket excavation resistance. Conclusions. The developed method of calculating the excavation resistance takes into account the internal forces of bucket interaction with rock and makes it possible to increase the accuracy of maximum digging force calculation. It therefore becomes possible to more reasonably approach the choice of the excavator bucket turning hydraulic cylinder parameters and thereby increase the reliability and durability of the machine as a whole.

Experimental and transient CFD analysis of parallel-flow solar air collectors with paraffin-filled recyclable aluminum cans as latent heat energy storage unit

In the present study, it is aimed to improve the overall performance of a parallel-flow solar air collector (PSC) using phase change material (PCM)-based latent heat energy storage unit and recyclable materials. In the simulation part of this work, two PSCs including a collector without modification and a collector equipped with PCM filled aluminum cans have been analyzed. The simulation part of the current work is handling the flow of air through the collectors and melting-solidification of PCM material inside the aluminum cans. Considering the simulation study results, three different PSC configurations have been manufactured including an unmodified PSC, a PSC with PCM-filled aluminum cans on the front side of the absorber and a PSC with PCM-filled aluminum cans on both sides (back and front) of the absorber surface. According to the results of the analyses, utilizing PCM-filled aluminum cans in both surfaces of the absorber plate of the PSC improved numerically and experimentally obtained exergetic efficiency values as 61.70% and 74.03%, respectively. Moreover, enviro-economic analysis has been conducted within the scope of this work. The payback periods of the analyzed systems were between 2.17 and 2.43 years. Employing PCM in the both sides of the absorber surface decreased the payback time of the system as 10.69% in comparison to the conventional PSC. Moreover, using PCMs on the single and double side of the absorber plate improved the annual carbon dioxide savings as 22.68% and 35.42%, respectively.

Dynamic responses of aluminum alloy plates coated with polyurea elastomer subjected to repeated blast loads: Experimental and numerical investigation

As one of the commonly used component units of engineering structures, aluminum alloy plates will likely suffer from multiple blast loads in terrorist bombing attacks and industrial explosion accidents. Given such structures, the research of technical measures to resist extreme blast disasters is an important topic. Polyurea, is a potential excellent strategy for improving the blast resistance of aluminum alloy plates, with a promising application prospect. This study experimentally investigated the dynamic response and damage characteristics of polyurea-coated aluminum alloy plates under repeated blast loads, and the microscopic characteristics of polyurea material and Vickers hardness properties of aluminum material after loading were analyzed. Based on the developed numerical model, the plastic deformation and energy propagation laws of composite plates were analyzed. Finally, a parametric study on the coating position of polyurea, blast scaled distance, and number of blasts was conducted. The damage regularity of the aluminum plate was obtained, and the damage assessment was performed. The results revealed that polyurea coated on the back or double sides of the aluminum plate could exhibit improved blast resistance. Under repeated blasts, compared with that of the Category A plate (uncoated polyurea), the Category B plate (coated with polyurea on the back side) exhibited improvements of 33.9% and 31.3% in the local and overall deformation resistances, respectively. The Category C plate (coated with polyurea on both sides) exhibited improvements of 19.3% and 22.5%, respectively. Polyurea significantly alleviated the damage of the aluminum plates after two explosive loads.

Behavior of new hybrid connection between steel beam and concrete-encased composite column

A new bending connection between a steel beam and concrete-encased composite column (CECS) with a bolted flange plate is proposed which maintains the integrity of the column and allows for the interchangeability of the beam for improvement of the connection. The confinement of the steel plates and the central steel core (H-section column) is provided by reinforced concrete and cover plates, thus lateral torsional and local buckling of the through plate (TP) and the central core is prevented. Three full-scale samples of the proposed exterior connection with variable TP thickness and different bending capacities under lateral cyclic and constant axial loads in the column were tested. The moment contribution in the components and seismic behavior of the connection were studied. The load transfer to the panel zone occurred through four components in the bending plane; TP, concrete performance, tensile studs, and side plates. The average share of the resistant elements which is immediately behind the front plate were determined as 56%, 26%, 12.50%, and 5.5%, respectively. The internal panel zone remained undamaged and the stresses were below the yield limit, so that the plastic hinge could occur outside the connecting members in the beam. In general, the specimens with sufficient pre-tensioning in the connection bolts had stable hysteresis curves and less pinching. In addition, these specimens showed acceptable energy dissipation that provided a high ductility index.

Calculation and analysis of fluid-solid coupling of rocket sled supersonic water bucket braking process

In order to solve the problem of structural damage during the braking process of a rocket sled supersonic water bucket, which affects the braking effect, it is proposed to use the FEM fluid-solid coupling calculation technology to analyze the process of the water bucket entering the water brake. The fluid-solid coupling calculation results show that the limit braking state After the water bucket enters the water brake for 0.06ms, the stress at the entrance position exceeds the yield limit of the material, and the structure is severely deformed and damaged; under normal braking conditions, the water bucket enters the water brake for 0.4ms, the plate at the entrance of the bucket bends, and the structure is seriously deformed at 2ms, The structure is destroyed at 3ms. Using the penalty function fluid-structure coupling method, the numerical analysis of the model water bucket was carried out under two working conditions. Due to the unreasonable design of the bucket, the bucket entrance deformed and destroyed during braking. It is recommended to increase the structural strength of the water inlet side plate.

Developing geo-sequential reasoning about tectonic processes using computational simulations

ABSTRACT Explaining phenomena associated with a system involves describing a system’s structure and articulating the process through which the system’s structure changes over time. This paper defines geo-sequential reasoning in the context of plate tectonics and uses it to analyse how students explain the geological processes that occur along convergent boundaries as part of the plate tectonics system. This study was part of design-based research on an online Plate tectonics module that included simulation-based modelling developed for secondary school students. We analysed students’ explanations (n = 950) about phenomena found along a convergent boundary (1) as an oceanic plate and a continental plate move towards each other and (2) between two oceanic plates located on the opposite side of a tectonic plate from a divergent boundary. We also analysed images created by students of the simulation as evidence to support their explanations. We found that a majority of students used simulation-based evidence when describing the sequence of events along the convergent boundary and that the synced planet surface and cross-section views in the simulation supported students’ inclusion of processes responsible for the events. These findings have implications for how teaching and research with dynamic simulations can support reasoning built with temporal evidence.

Chemical reaction on MHD convective flow of second-grade fluid through a vertical porous channel with non-uniform wall temperature

We have examined the impacts of the suction and/ or injection on the magnetohydrodynamic convection fluctuating flow of secondary order fluids through the absorbent medium into a perpendicular channel by non-uniformed walls’ temperature. The fluid is subjected to a transversal magnetic domain as well as the velocity slips near the left side plate. The systematic resolutions of the non-dimensional equations were found and the impacts of the governed variables on velocity, temperatures, concentration profiles, skin frictions, rates of temperature and mass transports were explored. It is motivating to note that skin friction enhances channel plates as permeability enlarges. The magnitude of the velocity retards with an enhancement in Hartmann number and enlarges with an increase in the permeability parameter.

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.