Concave Surface Research Articles

Deposition of titanium films on complex bowl-shaped workpieces using DCMS and HiPIMS

Herein, the deposition of titanium films on complex bowl-shaped workpieces was conducted using direct-current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HiPIMS) methods, and the differences in the properties of the film deposited using these methods were investigated. Metallic titanium films were deposited on the inner (concave) and outer (convex) surfaces of a bowl-shaped workpiece. The deposition rate, crystal structure, microhardness, and cross-sectional morphology of the titanium films at different deposition angles with respect to the normal vector of the target surface were characterized. Results showed that HiPIMS films exhibited better uniformity in terms of the crystal texture, microhardness, and microstructure than that of DCMS films, for both concave and convex surfaces. The differences between the properties of the HiPIMS and DCMS deposited films can be attributed to the significantly reduced self-shadowing effect in the oblique incidence deposition provided by HiPIMS. The enhanced energetic bombardment of depositing species on the substrate in the ionization-rich HiPIMS plasma facilitates the deposition films with uniform crystal structures and properties. However, a distinct difference in the film deposition rates was observed for the different shapes of the substrates in both deposition techniques. The films deposited on concave surfaces showed better uniformity than that of the films deposited on convex surfaces. This phenomenon can be explained by considering both the effect of the substrate-to-target distance, line of sight and the electric field near the substrate. The results presented in this manuscript are therefore crucial for the coating design of objects with complex shapes when depositing pure metals using DCMS and/or HiPIMS for decorative, tribological, and tool applications.

Surface Charge Accumulation and Electric Field Distribution of Cone-Type Spacer in DC GIL

The surface charge accumulation on the spacer and the distortion of the surface electric field caused by it are the main reasons for the reduction of flashover voltage of DC GIL (Gas Insulated Transmission Line) spacers. A reasonable spacer structure helps to improve the surface electric field distribution. This paper considers the generation, migration, diffusion and recombination of free ions in GIL gas, and the nonlinear relationship between gas current density and electric field strength. A numerical model for the charge transport and accumulation in DC GIL is established. Based on this model, the surface charge accumulation and electric field distortion characteristics of cone-type spacer with different inclination angles and curvatures of the surface are investigated. The results show that the polarity of the accumulated charge on the two sides of the cone-type spacer is different from that on the inside and outside (concave and convex surface). The negative charge density in the concave surface is 1.6 times that of the positive charge density in the convex. The normal component of the electric field is the main reason for the formation of charge accumulation; The surface charge density of the cone-type spacer increases as its inclination angle increases. and there is a key position for the electric field along the both surfaces. The high-voltage side electric field decreases with the increase of the angle, and the electric field near the ground side increases with the increase of the angle; The smaller the curvature along the spacer, the higher the charge density. The research results can provide reference for structural optimization of cone-type spacer in DC GIL.

AI-DRIVEN Novel Approach for Liver Cancer Screening and Prediction Using Cascaded Fully Convolutional Neural Network.

In experimental analysis and computer-aided design sustain scheme, segmentation of cell liver and hepatic lesions by an automated method is a significant step for studying the biomarkers characteristics in experimental analysis and computer-aided design sustain scheme. Patient to patient, the change in lesion type is dependent on the size, imaging equipment (such as the setting dissimilarity approach), and timing of the lesion, all of which are different. With practical approaches, it is difficult to determine the stages of liver cancer based on the segmentation of lesion patterns. Based on the training accuracy rate, the present algorithm confronts a number of obstacles in some domains. The suggested work proposes a system for automatically detecting liver tumours and lesions in magnetic resonance imaging of the abdomen pictures by using 3D affine invariant and shape parameterization approaches, as well as the results of this study. This point-to-point parameterization addresses the frequent issues associated with concave surfaces by establishing a standard model level for the organ's surface throughout the modelling process. Initially, the geodesic active contour analysis approach is used to separate the liver area from the rest of the body. The proposal is as follows: It is possible to minimise the error rate during the training operations, which are carried out using Cascaded Fully Convolutional Neural Networks (CFCNs) using the input of the segmented tumour area. Liver segmentation may help to reduce the error rate during the training procedures. The stage analysis of the data sets, which are comprised of training and testing pictures, is used to get the findings and validate their validity. The accuracy attained by the Cascaded Fully Convolutional Neural Network (CFCN) for the liver tumour analysis is 94.21 percent, with a calculation time of less than 90 seconds per volume for the liver tumour analysis. The results of the trials show that the total accuracy rate of the training and testing procedure is 93.85 percent in the various volumes of 3DIRCAD datasets tested.

Structural studies of human FIS1 reveal a dynamic region important for DRP1 recruitment and mitochondrial fission

Mitochondrial fission protein 1 (Fis1) and dynamin-related protein 1 (Drp1) were initially described as being evolutionarily conserved for mitochondrial fission. However, the role of human Fis1 in this process remains unclear. In budding yeast, where Fis1 helps to recruit Drp1 from the cytoplasm to mitochondria for fission, the N-terminal “arm” of Fis1 is required for function. The yeast Fis1 arm interacts intramolecularly with a conserved concave surface that governs in vitro interactions with yeast Drp1.

Umbrella Sampling Simulations of Carbon Nanoparticles Crossing Immiscible Solvents.

We use molecular dynamics to compute the free energy of carbon nanoparticles crossing a hydrophobic–hydrophilic interface. The simulations are performed on a biphasic system consisting of immiscible solvents (i.e., cyclohexane and water). We solvate a carbon nanoparticle into the cyclohexane layer and use a pull force to drive the nanoparticle into water, passing over the interface. Next, we accumulate a series of umbrella sampling simulations along the path of the nanoparticle and compute the solvation free energy with respect to the two solvents. We apply the method on three carbon nanoparticles (i.e., a carbon nanocone, a nanotube, and a graphene nanosheet). In addition, we record the water-accessible surface area of the nanoparticles during the umbrella simulations. Although we detect complete wetting of the external surface of the nanoparticles, the internal surface of the nanotube becomes partially wet, whereas that of the nanocone remains dry. This is due to the nanoconfinement of the particular nanoparticles, which shields the hydrophobic interactions encountered inside the pores. We show that cyclohexane molecules remain attached on the concave surface of the nanotube or the nanocone without being disturbed by the water molecules entering the cavity.

Shape optimization of orthopedic porous scaffolds to enhance mechanical performance

Polymeric bone scaffolds are supposed to temporarily bear the external mechanical forces applied to the injured area. The implanted scaffolds should satisfy both mechanical and cell-proliferation requirements. In this study, to design an optimum scaffold structure from mechanical and cell growth perspectives, a new scaffold structure named MFCC (Modified Face Centered Cubic) is introduced, which is based on the Face Centered Cubic (FCC) arrangement of spherical pores. The geometric parameters of the scaffold structure are optimized to increase the stiffness of the scaffolds with 70%, 75%, and 80% porosities. The optimized MFCC scaffolds satisfy the cell growth requirements and show greater elastic modulus compared to regular OCS (Orthogonal Cylindrical Struts) scaffolds. For validation, the designed scaffolds made by the finite element optimization process were 3D printed, tested and compared with the OCS scaffolds. The results show that the gradual cross-section variation of the spheres in the optimized scaffold reduces the stress concentration and distributes the applied mechanical loads more uniformly compared to OCS scaffolds. Moreover, from the cell growth perspective, a spherical pore with a concave surface provides a better surface for the proliferation of cells. The optimized MFCC scaffolds are stiffer in small strains and have a greater apparent yield stress compared to the OCS scaffolds at the same porosity. The enhancement in the stiffness of the scaffold is shape attributed and is independent of the material used. Therefore, the same percentage increase in the stiffness is achievable for a broad range of materials. The presented new design with improved stiffness helps to enhance the quality of load-bearing scaffolds.

Droplet splashing on curved substrates

Droplets impacting dry solid substrates often splash above a certain threshold impact velocity. We hypothesise that substrate curvature alters splashing thresholds due to a modification to the lift force acting on the lamella at the point of breakup. We have undertaken high-speed imaging experiments of millimetric droplets impacting convex and concave surfaces to establish splashing thresholds and dynamics across a wide range of substrate geometries and impact conditions. Our findings indicate that the tendency of droplets to splash is proportional to the reciprocal of the substrate’s radius of curvature, independent of whether the substrate is convex or concave, with it being harder for droplets to splash on small spheres. Moreover, we consistently parameterise the axisymmetric splashing threshold across all curved substrate geometries via a modification to the well-known splashing ratio. Finally, the splashing dynamics resulting from initial asymmetry between the impacting droplet and curved substrate are also elucidated.

Thin liquid films on a rotary bell atomizer in surface-following coordinates

This article analyzes a published formulation of the Navier–Stokes equations cast into surface-following coordinates and provides some additional mathematical background to follow the article. Ubiquitous in the paint shops of automotive plants around the world, a high-speed rotary bell is succinctly described as a rapidly spinning concave axisymmetric surface with liquid paint supplied from a port coinciding with the center of rotation. The spinning surface transfers momentum to the paint film causing it to flow outward. Upon reaching the bell periphery, it is flung off, subsequently forming an atomized spray transferred to an automotive body through advection and electrostatics. Common analytical frameworks of rotating films were spherical or cylindrical coordinate systems where the wetted surface profile of the bell was constrained to follow a coordinate axis. This led to solutions for films modeled with conical, disk-like, or partial hemispherical profiles. An alternative was a more general case using a surface-following orthogonal curvilinear coordinate system along with its derived vector operators. In the unique case of a thin film, these results validated a simpler pattern found in common coordinate systems.

Баклаги салтівської культури в збірці Дніпропетровського національного історичного музею імені Дмитра Яворницького

Проаналізовано колекцію баклаг кінця VIII – першої половини ІХ століття, виготовлених нагончарному крузі, зі збірки Дніпропетровського національного історичного музею імені ДмитраЯворницького. Ці вироби салтівської культури – специфічний і малочисельний тип посуду. Доколекції увійшли три баклаги ІХ століття, знайдені на території колишньої Катеринославськоїгубернії та м. Дніпра, а також одна баклага, передана 2010 року з с. Лобойківка Петриківськогорайону Дніпропетровської області. Проаналізовано відмінності між зразками цього загаломтипового посуду. Подано відомості про аналогії цим посудинам, знайдені на пам’ятках степовогота лісостепового варіантів салтівської культури. Among the antiquities of the Saltiv culture there is a specific and non-numerical type of ceramicutensils – water bottles or flasks, which were used to transport a small amount of liquid.The article deals with three water bottles of the late 8th – early 9th centuries, which are stored in thefunds of the Dmytro Yavornytsky National Historical Museum of Dnipro and one water bottle, which wastransferred to the museum from the village of Loboykivka of the Petrykivka District of the DnipropetrovskRegion in 2010. The location of one of these water bottles is unknown. One of them has been found in thegrated former Ekaterinoslav Government, and the second one has been found in 1958 at the mouth ofthe Shiyanka river, now it’s a territory of the city of Dnipro. All four vessels have a curved front surface,a flat or slightly concave back surface, a cylindrical body, a high throat (lost in one water bottle), formedseparately and then attached to the main part of the vessel, two handles, oval in cross section, fixed onopposite sides from the throat. One water bottle is decorated with a pentagonal star in a round medallion,and two – with medallions. The medallions are formed from the same clay as the water bottle itself. Onthe water bottle, found in 2010, there are remnants of a color ornament. These are elements applied withbrown, light brown paint and white engobes.The article also analyzes the differences between different samples of this mostly the same type ofutensils – the shape of the crown, the shape of the handles, the ornament (or lack thereof). The authorconcludes that these differences are not enough to distinguish certain types and kinds of this crock.The described water bottles are characteristic of the antiquities of the Saltiv culture and havea number of analogies on the monuments of its steppe and forest-steppe variants – settlements, nomadicstations, cemeteries, as well as in the form of accidental finds. They were made in the workshops of theCrimea to order of the steppe and forest-steppe population, most likely for horsemen. Mostly made of thesame clay as amphorae and in the same workshops. But there are single water bottles that are made ofanother clay mass with the addition of chalk and hardness. It is possible that they are not made in Crimeanworkshops, but are imitations of these forms by local craftsmen.Water bottles from the Dmytro Yavornytsky National Historical Museum of Dnipro complementa number of already known and published vessels and expand the range of their existence.

Bioinspired three-dimensional hierarchical micro/nano-structured microdevice for enhanced capture and effective release of circulating tumor cells

The efficient capture and release of the circulating tumor cells (CTCs) are promising for the CTC related cancer diagnosis and subsequent analysis. However, it is a great challenge to isolate and enrich the rare CTCs from the complex peripheral blood sample, which inhibits its broad translating to the clinical applications. Although various papers reported that the nanostructure substrates can improve the capture efficiency of CTCs, few of researches constructed 3D hierarchical micro/nano-structured microdevice to enhance the efficiency of CTC capture and release with a simple manner. Herein, a bio-inspirited 3D epithelial cell adhesion molecule (EpCAM) aptamer modified rose petal derived ZnO microchip (EpCAM-RPD-ZnO-Chip) was designed to realize efficient capture and release of the CTCs. The 3D rough spherical concave surfaces on the EpCAM-RPD-ZnO-Chip guaranteed the maximum contact with the CTCs, thus improving the capture efficiency. Moreover, simple release of CTCs by dissolving ZnO under moderate acidic condition was achieved. The topographical and target molecular recognition cooperatively contributed to highly efficient capture of CTCs. The scanning electron microscope (SEM) image clearly showed that the filopodias and lamellipodias of CTCs stretched and attached to the ZnO nanomaterials. In sum, the proposed 3D EpCAM-RPD-ZnO-Chip is expected to be a promising tool for capture and release of CTCs in clinical trials, which might lay a foundation for downstream analysis and precise drug susceptibility test for the cancer treatment.

Influence of geometry and operation conditions on the surface charge characteristics of DC‐GIL spacer

The surface charge characteristics of a ±200 kV gas-insulated transmission lines spacer are studied to understand the influence of geometry, ion transportation, applied voltage, and gas pressure on the surface charge distribution. The simulation result indicates that the geometry simplification would affect the surface charge distribution. A millimeter-level protrusion on the spacer causes an increase of 20 μC m−2 in charge density. A difference of 10 μC m−2 is found between the simulations based on the measured and calculated ion mobility. Moreover, it is found that the identical surface charge distribution cannot be achieved with the downsized model based on the identity of field strength, since ion transportation is affected by the scaling of geometry. The influence of gas pressure on the ion migration results in an initial excitation to the field variation, which further promotes the variation of surface charge via the dominative bulk conduction. Thus, with increasing pressure from 0.3 to 0.6 MPa, an increase of 8.4 μC m−2 is found on the convex surface, while a decrease of 5.5 μC m−2 is found on the concave surface. This investigation would be helpful for the simulation and experiment concerning the surface charge characteristics of spacers.

First Report of Coffee Leaf Rust Caused by Hemileia vastatrix on Coffee (Coffea arabica) in Hawaii.

Coffee is one of the most economically valuable specialty crops for which Hawaii is famous. It is produced commercially on >6,900 acres across six islands by more than 1,470 growers. It has a raw crop value of $55.9 million, while the value-added benefits of coffee-related industries exceed $148.5 million (USDA, 2021). In addition to high product quality, Hawaii also has the distinction of being the last major coffee growing region that is free of coffee leaf rust (CLR), a highly damaging disease caused by the obligate parasitic fungus Hemileia vastatrix Berk. & Broome. On October 21, 2020, a coffee grower in Maui County, Hawaii reported the presence of coffee leaf rust-like symptoms on coffee plants (var. 'Typica') at their farm with many trees heavily defoliated. Foliar symptoms consisted of yellowish-orange, circular lesions that often coalesced. On abaxial surfaces, these lesions appeared powdery. Urediniospores were mostly reniform, (25)27-34(36) × (17)18-28(29) µm, strongly echinulated on the upper (convex) surface and smooth on the lower (concave) surface, with hyaline to pale yellow-orange walls. Urediniospores incubated in molecular grade water for 10 min at 95 oC served as template for PCR targeting the internal transcribed spacer region of fungi using primers ITS1/ITS2, ITS3/ITS4, and ITS1/ITS4 (White et al., 1990). Amplification products underwent direct Sanger-based sequencing. Following primer sequence trimming, the sequence reads were assembled using CAP3 (Huang and Madan, 1999) and deposited in GenBank (Accession MW228837). Blastn analysis revealed > 99% nucleotide identity with isolates of H. vastatrix from Mexico (eg. KX260251) and Brazil (eg. MF627828). A voucher material from which both the morphological and molecular assays were performed was deposited in the National Fungus Collection (BPI 924818). Subsequent surveys on the islands of Hawaii, Lanai, and Oahu revealed the presence of coffee plants with symptoms of coffee leaf rust. To confirm pathogenicity, urediniospores from a symptomatic plant growing in Holualoa, Hawaii, were collected in gelatin capsules using a G-R Electric Manufacturing Portable Vacuum Pump with a mini cyclone spore adapter. The concentration of spores was adjusted to 1 x 105 spores/ml in sterile water using a Brightline Hemocytometer. The spore suspension was brushed onto the abaxial side of leaves from two C. arabica var. 'Typica' plants using a camel hair paintbrush. Two control plants were mock-inoculated with sterile water. Plants were placed in a dark humid chamber set at 22 oC for 48 hours, after which it was adjusted to 12 hours light under cool white fluorescent lighting. After 20 days small, chlorotic spots were visible on the adaxial leaf surface and a few spots contained orange urediniospores on the abaxial surface. Lesions expanded by day 34, followed by necrosis of the center area of several leafspots and leaf abscission was observed at day 70. The experiment was conducted twice. H. vastatrix was confirmed by both morphological and molecular examination of urediniospores recovered from the observed lesions. All mock-inoculated control plants remained asymptomatic. To our knowledge, this is the first report of CLR on coffee in Hawaii. This discovery is of great concern since CLR threatens not only the yield and quality of Hawaii-grown coffee, but also the economic viability of this historic and culturally important industry. Statewide monitoring for CLR continues and further work is needed to mitigate the impact of this discovery through the development of short- and long-term management strategies.

Highly Distinct Microbial Communities in Elevated Strings and Submerged Flarks in the Boreal Aapa-Type Mire.

Large areas in the northern hemisphere are covered by extensive wetlands, which represent a complex mosaic of raised bogs, eutrophic fens, and aapa mires all in proximity to each other. Aapa mires differ from other types of wetlands by their concave surface, heavily watered by the central part, as well as by the presence of large-patterned string-flark complexes. In this paper, we characterized microbial diversity patterns in the surface peat layers of the neighboring string and flark structures located within the mire site in the Vologda region of European North Russia, using 16S rRNA gene sequencing. The microbial communities in raised strings were clearly distinct from those in submerged flarks. Strings were dominated by the Alpha- and Gammaproteobacteria. Other abundant groups were the Acidobacteriota, Bacteroidota, Verrucomicrobiota, Actinobacteriota, and Planctomycetota. Archaea accounted for only 0.4% of 16S rRNA gene sequences retrieved from strings. By contrast, they comprised about 22% of all sequences in submerged flarks and mostly belonged to methanogenic lineages. Methanotrophs were nearly absent. Other flark-specific microorganisms included the phyla Chloroflexi, Spirochaetota, Desulfobacterota, Beijerinckiaceae- and Rhodomicrobiaceae-affiliated Alphaproteobacteria, and uncultivated groups env.OPS_17 and vadinHA17 of the Bacteroidota. Such pattern probably reflects local anaerobic conditions in the submerged peat layers in flarks.

Tool profile modification of hypoid gear machined by the duplex helical method

To avoid edge contact and stress concentration on the tooth surface of hypoid gear pairs machined by the duplex helical method for the drive axle of heavy-duty vehicles, a four-segment tool profile was designed for the simultaneous modification of the concave and convex surfaces of the pinion. First, a geometric model of the four-segment tool profile was established. Second, a mathematical model of the duplex helical method based on the four-segment tool profile was established, and a method for solving the tooth surface generated by the connecting points of the four-segment tool profile was presented. Finally, loaded tooth contact analysis based on finite element method was used to analyse the meshing performance of the gear pair obtained by the four-segment tool profile modification. The results of the original and modified gear pairs were compared. The tooth surface modification inhibited edge contact, improved the stress distribution, and decreased the maximum contact stress of the tooth surfaces, thereby improving the fatigue and wear life of the gear pair.

ELID Mirror Surface Grinding for Concave Molds by Conductive Elastic Wheel Containing Carbon Black

Elastic grinding wheels have previously been adopted for the development of the mirror surface finishing method for concave spheres. In this study, new conductive elastic grinding wheels, to which electrolytic in-process dressing (ELID) can be applied, are developed; the aim of the study is to address the challenge of maintaining a constant removal rate for rubber bond wheels. When ELID grinding is performed using a non-diene (isobutane isoprene rubber, IIR)-based wheel, a larger removal amount is achieved, and a higher-quality surface is also achieved compared to a diene (acrylonitrile-butadiene rubber, NBR)-based wheel. In addition, to investigate the effect of grinding wheel bond hardness on the removal amount and ground shape accuracy, grinding wheels with various levels of hardness are prepared by controlling the amount of carbon black contained in them, and grinding experiments are conducted. Thus, a larger removal amount is achieved using a harder grinding wheel, but the roughness of the ground surfaces deteriorates. Therefore, in practice, it is necessary to select an appropriate grinding wheel that can achieve both productivity and surface quality. Finally, to obtain a high-quality mirror finish on a concave spherical surface, ELID grinding is performed on the workpieces as is done for spherical lens molds. Thus, high-quality mirror surfaces with roughness Ra < 10 nm were generated. When the work pieces are ground using a grinding wheel of the same radius, excessive removal occurs at the edge of the concave spherical profile, decreasing the form accuracy. Numerical simulation demonstrates that chamfering of the grinding wheel is effective for improving the shape accuracy. The results of this study are expected to contribute to automation and cost reduction in the mirror-finishing process for concave molds.

Structure and antiviral activity of a pectic polysaccharide from the root of Sanguisorba officinalis against enterovirus 71 in vitro/vivo

The increasing prevalence and pandemic risk of viral diseases warrant the development of safe and effective treatments. In this study, we aimed to elucidate the structure and anti-enterovirus 71 (EV71) effects of polysaccharides isolated from the roots of Sanguisorba officinalis (SO), traditionally used for infectious diseases. The purified polysaccharide (S-a3) was a homogenous macromolecule (260.4 kDa) with a concave and porous surface. Linkage and NMR analyses confirmed that S-a3 is a polysaccharide interlinked with homogalacturonan, rhamnogalacturonan-I, 1,4-α-glucan, and arabinogalactan. S-a3 significantly inhibited cell death and viral gene expression in EV71-infected Vero cells, and alleviated EV71-induced body weight loss, death, and paralysis in the hSCARB2-transgenic mouse model. The effective dose of S-a3 was non-toxic to cells and mice. The antiviral mechanism of S-a3 was associated with the disruption of EV71 attachment to host cells. Our findings demonstrate that polysaccharides from SO can be a safe and effective treatment for EV71 infection.

A detailed analysis of flow and heat transfer characteristics under a turbulent intermittent jet impingement on a concave surface

A computational study is carried out of the 3-D flow field and heat transfer under a turbulent intermittent circular jet impingement on a concave surface. The control-volume procedure with the SIMPLE algorithm is employed to solve the unsteady RANS (use full form) equations. The RNG k-? model is implemented to simulate turbulence due to its success in predicting similar flows. The numerical results are validated by comparing them with the experimental data. The effects of jet Reynolds number and oscillation frequency on the flow and heat transfer are evaluated. The profiles of instantaneous and time-averaged Nusselt numbers exhibit different trends in axial, x-directions and circumferential, s-directions. It is found that increasing frequency from 50 to 200 Hz results in considerable time-averaged Nusselt number enhancement in both axial and curvature directions. The intermittent jet at a frequency of 200 Hz enhances the total average Nusselt number by 51.4%, 40%, and 33.7% compared to the steady jet values at jet Reynolds numbers of 10000, 23000, and 40000, respectively. In addition, a correlation for the average Nusselt number is proposed depending on the Reynolds number and the Strouhal number.

Применение ГИС-технологий и карт пластики рельефа для исследования оползней Чирчикского бассейна

In recent years, the number of natural disasters has significantly increased, including those caused by exogenous geological processes, one of the leading among which are landslides, leading to environmental, engineering, social and economic consequences. The investigated Chirchik basin of the Republic of Uzbekistan is characterized by complex geomorphological, hydrological and geological conditions, as well as the presence of an active geodynamic process, which predetermined the development of landslides here. Currently, various methods are used for the integrated study of landslides of various genesis. Along with traditional methods, various tools of geographic information systems (GIS) are widely used. The use of GIS-processing of digital elevation models makes it possible to fully describe the development of landslide processes: quickly obtain information about morphometric indicators (height, inclination angle, slope exposure) in any model, analyze slope steepness and exposure, frequency runoff, generate contour lines, etc., as well as to map them. Another method of research is the method of relief plastics, the essence of which is the geometric transformation of the contours of topographic maps, it consists in the use of a new topographic map—relief plastics based on litodynamic flows. The proposed methodology for the integrated application of GIS technologies and plastic flow maps was developed taking into account the work performed by foreign and domestic specialists. This methodology applied to landslide processes study in the Baibaksay-Sulisay section of the Chirchik basin. As a result, digital elevation models were compiled based on SRTM and QiuckBird remote sensing materials, based on the digital elevation model, using the theory, a map of convex and concave surfaces was created.

A review of parabolic collector with shell and tube heat exchanger

The ever-increasing global need for energy makes it unavoidable to support the use of essential coffers (box or cabin). The sun is one of the most abundant and almost indestructible energy sources in our world. The goal of this study is to compare three alternative materials in order to improve or maximize the efficiency and other characteristics of the solar collector. Aluminum- 6061, Stainless Steel – 304 and Mild Steel - EN24 are the three materials. Solar collectors with a parabolic trough are physical devices with an interior covering of mirrors or reflecting materials. The collector is shaped like a concave surface. These troughs have a single axis, which means they may be rotated. These troughs have a single axis, which means they can only rotate in one direction. The east–west orientation is the most common and typical direction for solar collector placement. These collectors are also used in the north–south direction in various parts of the world and by some homes. The incident radiation on the collector heats a specific fluid as it flows through the tubes or pipes of the collector. Because they are in the shape of a parabola, solar collectors are also known as parabolic trough collectors. Despite the fact that the interior surface is coated with reflecting materials, mirrors are still used. The collector's form aids in the focus of falling light or radiation on the tubes. The shape of conventional solar collectors and parabolic solar collectors is what distinguishes them. One of the solar collector's most important qualities is this distinction. Mechanical and geometrical characteristics are among them. This reduces, if not completely eliminates, losses in the collection. These characteristics enable solar collectors to work at higher temperatures.

Durability and corrosion behaviors of superhydrophobic amorphous coatings: a contrastive investigation.

Superhydrophobic surfaces can be derived from roughening hydrophobic materials. However, the superhydrophobic surfaces with various micro/nano morphologies present variations of chemical and mechanical durability, which limits their practical applications. Very little actually is known about comparing durability and corrosion resistance of concave and convex superhydrophobic surface structures systematically. In this paper, two kinds of superhydrophobic AlNiTi amorphous coatings with concave and convex surfaces were obtained by chemical etching and hydrothermal methods, respectively. Benefiting from nanoscale sheet structure, the convex superhydrophobic coating displays higher water-repellence (contact angle = 157.6°), better self-cleaning performance and corrosion resistance. The corrosion current density of the convex superhydrophobic surface is approximately one order of magnitude smaller than the concave superhydrophobic surface. Besides, the long-term chemical stability and mechanical durability of both superhydrophobic surfaces were also investigated. The formation and damage mechanisms of these two kinds of superhydrophobic surfaces were proposed. It is hoped that these investigations could provide clear guidance for the real-world applications of superhydrophobic amorphous coatings.