Wavy Shape Research Articles

The Influence of Claystone Type on Landslide Hazard: A Case Study

The landslide is more common in locations with steep slopes and is unstable. Developing an early warning system is the aim of this study, which focuses on Nanggulan, Yogyakarta Special Region-Indonesia. The Nanggulan has a wavy shape with a minor slope and is made up of Eocene sedimentary rocks. The landslide indicators, such as curved walls, cracked roads, fractured building walls, subsided building floors, sinkholes, and the creation of crown scarps, were discovered at various sites. X-Ray Diffraction (XRD) analysis and soil index properties of rock and soil samples, were used in the research. The XRD examination revealed the presence of smectite-group clay minerals (monmorillonite and saponite). Calculating the soil index parameters yielded that the soil has a specific gravity of 2.173–2.62, water content of 18.207–47.653%, liquid limit of 45–77%, plastic limit of 21–43%, plasticity index of 18–42%, cohesiveness of 1–91 kPa, and a friction angle of 10°–54°. The direction of the slope is more than 20°, so there is little possibility of planar failure, and the Nanggulan is stable. However, from the smectite-group clay minerals, the plasticity index and the liquid limit value indicate that the rock is cohesive and easy to move when it is wet. This form of landslide typically occurs on gently sloping terrain, is controlled by expansive lithology, has a relatively slow movement rate, and indicates that the landslide type was creep.

Effect of absorber shape on energy, exergy efficiency and enviro‐economic analysis of solar air collector: An experimental study

AbstractThe efficiency of solar air collectors, which are intended to convert solar energy into thermal energy, is the subject of numerous studies that aim to assess and improve it. Solutions for sustainable energy heavily rely on these systems. Making the right choice regarding the best method for absorbing solar radiation and reducing heat losses is what will ultimately lead to their improved performance. In this work, wavy and corrugated absorbers were suggested inside a solar air collector. The aim of this article is to study experimentally the thermal performance of the solar air collector when using wavy shape of absorber and corrugated shape of absorber instead of the flat shape of absorber under the same weather conditions of Sfax region central‐eastern of Tunisia. The suggested shapes of absorber augmented sun exposure and heating area. The results obtained from this experimental study show that switching from a flat plate absorber to both wavy and corrugated absorbers resulting significant performance gains. The absorber with waves showed a significant improvement in daily thermal efficiency of 22.89%, and the absorber with corrugations showed an even greater improvement of 40.56%. Comparable patterns were noted in daily exergy efficiency, where the corrugated absorber demonstrated an astounding 44.83% increase and the wavy absorber provided a 23.24% improvement. Notably, when total cost savings and monthly CO2 reduction were taken into account, the corrugated absorber turned out to be the best option. These findings highlight the importance of absorber form in optimizing thermal and energy efficiency, which may have positive effects on the economy and environment.

The effect of initial pressure and temperature on the flow in a three-dimensional cavity filled with paraffin/Cu nanostructure with a wavy lower wall and a movable upper wall using molecular dynamics simulation

Phase change materials (PCMs) are very suitable for the storage of thermal energy. Heat transfer plays a crucial role in many important industrial processes in today's industrial environment. Thus, it is crucial to examine and comprehend this occurrence properly. This work uses molecular dynamic simulation to examine the effect of initial pressure (IP) and temperature (Temp) on the thermal efficiency of phase change materials inside a three-dimensional cavity. The hollow contains paraffin/Cu nanoparticles and has a bottom wall with a wavy shape and an upper wall that can be adjusted. The results of the equilibration stage indicated that the kinetic and potential energies converge to 2100 eV and -95472.50 eV after 10 ns. Next, the results show that increasing IP resulted in the reduction of maximum velocity and Temp, which decreased from 0.0099 Å/ps and 898 K to 0.0090 Å/ps and 888 K. Furthermore, the results show that by increasing IP, the heat flux and thermal conductivity decrease from 9.95 W/m2 and 1.45 W/m.K to 8.89 W/m2 and 1.26 W/m.K. Conversely, as the initial Temp rose from 300 to 350 K, so did the velocity (0.0125 Å/ps) and Temp (990 K). Furthermore, the thermal conductivity and heat flux increased to 1.69 W/mK and 11.25 W/m2, respectively. This study reveals how molecular dynamics simulations provide insights into the effects of initial pressure and temperature on the flow and thermal behavior of a paraffin/copper nanostructure. The findings improve understanding of nanofluid and phase change material behavior, aiding the design of more efficient PCM-based systems for thermal energy storage and heat transfer applications. In general, the results of this research illuminate the complex relationship among IP, Temp, and thermal properties of phase change materials. This knowledge is of great significance as it can guide the formulation of novel approaches to enhance the thermal efficiency of these materials in practical applications.

Riparian plant community structure and assembly processes differed by variations in riverbank curvatures: implications for restoring habitats along the Three Gorges Reservoir

Abstract A meandering riverbank plays a vital role in maintaining natural river ecosystems, providing habitats for riparian vegetation. However, dams have significantly altered riverbank shapes. To restore the riparian ecosystems, it is imperative to understand how different riverbank curvatures influence them. This study aims to uncover the ecological impacts of riverbank curvature on the structure and assembly process of plant communities in the riparian zone of the Yangtze River, regulated by the Three Gorges Dam (TGD) in China. We categorized the riparian zones into four types: cove, lobe, wavy, and linear shapes. We documented the composition and diversity of riparian plant communities. Our findings revealed that wavy and cove riverbanks exhibited greater species diversity (with Shannon-Wiener diversity index values 1.5 times higher) compared to communities along linear riverbanks. Furthermore, the analysis of functional traits indicated that wavy riverbanks promoted the differentiation of plant functional traits, thus enhancing ecosystem functions, with functional dispersion index (FDis) values 1.3 times higher than those of linear riverbanks. Significant variations in the assembly of riparian communities were also observed among different riverbanks, with standardized effect size (SES) values indicating a higher degree of niche differentiation in cove riverbanks (SES = 0.4) compared to linear riverbanks (SES = -0.6). These results highlight the ecological importance of diverse riverbank curvatures in influencing the diversity, structure, and assembly of riparian communities along waterway. In conclusion, this study underscores the necessity of maintaining or restoring various natural morphological curvatures when rehabilitating riparian communities along rivers impacted by human activities.

A Novel Cooling System by Surface Corrugation and Nanofluid Utilization for the Performance Improvement of Photovoltaic Module Coupled with Thermoelectric Generator and Efficient Computations by Using Artificial Neural Network-Based Hybrid Scheme

For a photovoltaic module coupled with thermoelectric generator, a unique wavy cooling channel is proposed, and its performance is numerically assessed by using three-dimensional computations. The cooling channel uses nanofluid of alumina–water with various shaped nanoparticles (spherical, cylindrical and brick). Numerical simulations are performed for a range of parameters for the corrugation amplitude (0≤Amp≤0.1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0 \\le \ ext {Amp} \\le 0.1$$\\end{document}), wave frequency (2≤Nf≤16\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2 \\le \ ext {Nf} \\le 16$$\\end{document}), nanoparticle loading quantity (0≤SVF≤0.03\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0 \\le \ ext {SVF} \\le 0.03$$\\end{document}), and nanoparticle shape (spherical, brick, and cylindrical). We analyze the photovoltaic module’s average temperature and temperature uniformity for a variety of parameter variations. When nanofluid and greater channel corrugation amplitudes are utilized, the average panel surface temperature is decreased more. A wavy shape of the cooling channel at the maximum corrugation amplitude yields a cell temperature reduction of 1.88 o\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\ ext {o}$$\\end{document}C, while frequency has little impact on average cell temperature and its uniformity. The best-performing particles are those with cylindrical shapes, and the drop-in average photovoltaic temperature with solid volume fraction is essentially linear. As utilizing cylindrical-shaped particles, the average temperature of corrugated cooling channels decreases by around 1.9 o\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\ ext {o}$$\\end{document}C as compared to flat cooling channels with base fluid at the greatest solid volume fraction. As compared to un-cooled photovoltaic, cell temperature drops by around 43.2 o\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\ ext {o}$$\\end{document}C when employing thermoelectric generator. However, temperature drop value of 59.8 o\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\ ext {o}$$\\end{document}C can be obtained by using thermoelectric generator and nano-enhanced wavy cooling channel utilizing cylindrical-shaped nanoparticles. An hybrid computational strategy for the fully coupled system of photovoltaic with cooling system is provided, which reduces the computational time by a factor of 75.

Magnetic Membranes for Cell Growth Under Curved and Reversible Deformations

Magnetic Membranes for Cell Growth Under Curved and Reversible Deformations

The Bombardment History of the Giant Planet Satellites

The origins of the giant planet satellites are debated, with scenarios including formation from a protoplanetary disk, sequential assembly from massive rings, and recent accretion after major satellite–satellite collisions. Here, we test their predictions by simulating outer solar system bombardment and calculating the oldest surface ages on each moon. Our crater production model assumes the projectiles originated from a massive primordial Kuiper Belt (PKB) that experienced substantial changes from collisional evolution, which transformed its size frequency distribution into a wavy shape, and Neptune’s outward migration, which ejected most PKB objects onto destabilized orbits. The latter event also triggered an instability among the giant planets some tens of Myr after the solar nebula dispersed. We find all giant planet satellites are missing their earliest crater histories, with the likely source being impact resetting events. Iapetus, Hyperion, Phoebe, and Oberon have surface ages that are a few Myr to a few tens of Myr younger than when Neptune entered the PKB (i.e., they are 4.52–4.53 Gyr old). The remaining midsized satellites of Saturn and Uranus, as well as the small satellites located between Saturn’s rings and Dione, have surfaces that are younger still by many tens to many hundreds of Myr (4.1–4.5 Gyr old). A much wider range of surface ages are found for the large moons Callisto, Ganymede, Titan, and Europa (4.1, 3.4, 1.8, and 0.18 Gyr old, respectively). At present, we favor the midsized and larger moons forming within protoplanetary disks, with the other scenarios having several challenges to overcome.

On the free vibration characteristics of multiscale hybrid conical panels utilizing Chebyshev–Ritz route

This study investigates the vibrational behavior of three-phase polymer-glass fiber (FG)-carbon nanotubes (CNT) nanocomposites conical panels. Effects of the wavy shape of CNTs and the viscoelastic nature of the polymer matrix are considered. First and foremost, the equivalent material properties are estimated in the context of a three-step hierarchical approach. Then, the governing equations are attained by combining the first-order shear deformation theory (FSDT) and Hamilton’s principle. Furthermore, the Ritz method is employed to extract the frequency responses with the help of Chebyshev polynomials for both simply supported and clamped ends panels. For the parametrical studies, the effect of different geometrical constraints, for instance, the effects of relaxation time and the effect of considering different waviness coefficients for the CNT, are reported. The findings of this paper reveal the significant effect of the viscoelastic properties of the polymer matrix on the estimation of the dimensionless frequency. For instance, under simply supported boundary conditions and a relaxation parameter of 60 s, the frequency of the structure reduces by approximately 23% after 100 s.

The Glanular-Frenular Collar (GFC) technique: Dual approach to hypospadias reconstruction

The Glanular-Frenular Collar (GFC) technique has evolved since it was first described in 2017. The technique involves reconstruction of the septum glandis, which has been overlooked in the history of hypospadias, and formation of the frenulum, creating the ventral wall of the glanular urethra without dissecting the glans, leaving room for the formation of the navicular fossa. We present a case of distal hypospadias corrected with the GFC technique and demonstrate the important steps of the surgical technique. The aesthetic result corresponded to the normal anatomy of the glans and frenular triangle, and the functional result showed a free and wavy shape of urine that resembled the normal flow from the urethra. In the normal anatomy of the penis, the wings of the glans are separated ventrally by the septum glandis and the frenulum. The navicular-shaped glanular urethra and its vertical, elliptical opening are covered by the fibroelastic septum glandis, unlike the penile urethra, which is surrounded by the corpus spongiosum. Reconstruction of hypospadias should include the formation of a septum glandis, frenulum, and navicular fossa. The GFC technique demonstrates the importance of a dual surgical approach for glanular and penile urethra reconstruction.

An Experimental Study on the Effectiveness of the Backward-Facing Step Technique on Small-Scale Horizontal-Axis Wind Turbine Rotor Blades

The aim of this research work was to explore how modifying the design of small-scale HAWT rotor blades through the backward-facing step technique affects their efficiency under varying wind speeds. The study involved altering step parameters such as location, length, and depth to create four distinct stepped blade shapes and enhance the aerodynamic performance of a rotor with a diameter of 280 mm. A specific blade profile, NREL S822, was selected to meet both aerodynamic and structural criteria. The rotor models were examined at a Reynolds number of 4.7 × 104 for wind speeds between 8.5 and 15.5 m/s and tip-speed ratios between 2 and 5. The experimental results indicated that for certain geometric step parameter values, the efficiency of the rotor model (B3) increased by approximately 47% compared to the base model (B1), particularly for tip-speed ratios lower than around 3.2. However, beyond this point, the rotor efficiency dropped significantly, reaching approximately 60% in one case. Additionally, a hybrid rotor model (B6) was generated by combining the shape of the rotor model (B4) with the most efficient rotor model from the literature, generated using the leading-edge wavy shape technique. This hybrid rotor model enhanced rotor efficiency for specific values of tip-speed ratio and also ensured its smoother operation. Overall, the rotor model (B2), distinguished by smaller step parameter values and a shift as well as broadening of the power coefficient curve towards lower tip-speed ratio values, exhibited a higher peak power coefficient, approximately 1.4% greater than the base rotor (B1). This increase occurred at a lower tip-speed ratio, allowing the rotor to operate with higher efficiency across a broader range of tip-speed ratios.

Design of the Microchannels Heat Sink to Augment the Thermal Performance Using Different Type of Cavity with or without Wavy Channel

The development of innovative micro sinks design stems from the urge to perform efficient cooling at a cost of low pressure drop for more miniaturized electronic equipment. The three-dimensional investigations have been carried out with disruptive structures in rectangular microchannels. Microchannel heat sinks with triangular cavity, trapezoidal cavity, wavy plane channel, wavy triangular cavity, and wavy trapezoidal cavity have been considered. The performance variations are evaluated based on the average Nusselt number, friction factor, and thermal performance within the range of Reynolds numbers from 141 to 498. The highest thermal performance is achieved by wavy trapezoidal cavity among all channels. The parametric geometrical studies have also been carried out by varying relative geometric parameters such as relative amplitude, relative cavity length, and relative cavity width. The highest heat transfer enhancement equal to 2.33, for the same channel has been achieved with the combination of relative amplitude; relative cavity length and relative cavity width is equal to 0.75, 0.055, and 0.75, respectively at Reynolds number equal to 498. The wavy shapes give better mixing by creating of additional vortices or dean vortices to increase heat transfer with minimum pressure drop.

Numerical investigation of forced convection flow of a complex Bingham–Papanastasiou fluid between two concentric

This research presents a numerical investigation of the flow field and heat transfer of a Visco-plastic fluid, The Bingham-Papanastasiou model is used to examine the flow field and forced convection heat transfer of a Viscoplastic fluid between two concentric cylinders with a wavy inner surface. By focusing on this particular configuration (wavy inner cylinder shape), where the inner surface exhibits as the hot wall while the outer surface is considered as the cold wall. This investigation is numerically achieved by using the Comsol Multiphysics, which is based on the finite‐volume method, employing Galerkin’s method for solving the governing equations. The parameters studied in this research are expressed with the following values: r/ R=1/3, Reynolds number (Re=1, 10, 50), and undulation number (nu=0, 6, 12, 24). Increasing the inertia parameter results in a higher intensity of thermal buoyancy, positively influencing heat transfer, particularly at Re=50. Furthermore, the acceleration of flow within the investi-gated space improves the hydrodynamic behavior, facilitating the exchange of thermal energy between the hot and cold walls. Additionally, it has been discovered that an undulating shape with a specific number of undulations (nu=6) maximizes hydrothermal performance within the investigated volume. The presence of these undulations enhances fluid mixing and dis-rupts the formation of stagnant regions ,which leading to improved heat transfer.

Research on seismic performance of corrugated web rigid structures

Abstract: Corrugated web H-beam refers to a steel beam with a wavy shape along its length, which is extensively utilized in various parts of building structures such as beams, columns, and walls. It serves the purpose of connection and support, while the corrugated or folded design enhances the shear resistance and out-of-plane stiffness of the web to some extent. However, despite their advantages including high strength, stiffness, and lightweight construction, relevant regulations stipulate that these members can only be used in lower-intensity applications or higher-intensity scenarios if specific conditions are met. One crucial condition is that the ratio between the design value of axial force subjected to seismic action and the product of the member's flange section area and steel's tensile strength should not exceed 0.4. In this study, we aim to further investigate the seismic characteristics and applicable intensity of corrugated steel structures under earthquakes through large-scale finite element ABAQUS simulations. We will observe dynamic characteristics and failure modes of corrugated rigid frame structures using elastic-plastic time-history analysis methods as well as examine plastic deformation features of steel beam members under low cyclic loads via hysteretic analysis methods. The findings demonstrate that when properly designed with reasonable beam spans, corrugated web rigid frame structures can still be employed in high-intensity areas above 7 degrees even when subjected to an axial compression ratio up to 0.5.

Microstructure generation algorithm and micromechanics of curved fiber composites with random waviness

During multiscale modeling and analysis of composite materials, accurately capturing the distinctive microstructural features of the material is essential. This is achieved by generating a representative volume element (RVE). Fiber reinforcements in composites can exhibit various shapes, including straight, slightly wavy, or complex shapes, depending on the inherent properties or the manufacturing process. Fibers are characterized based on their tortuosity, spread, and orientation distribution. It is crucial to account for these geometrical attributes during the microstructure generation and subsequent micromechanics modelling as they significantly influence the effective properties of the composite. The present work describes a novel algorithm capable of modeling a broad range of 3D periodic microstructures with fibers having random waviness. The effects of various parameters in the algorithm are studied to understand their influence on fiber shapes. This is followed by finite element analysis of the generated RVEs using the embedded element technique to quantify the microstructure- mechanical properties relationships. Finally, guidelines on the usage of the proposed model to generate fibers with desired microstructure is elucidated. A comprehensive framework for modeling and analyzing microstructures with complex fiber geometry is outlined.

Investigation of joints from corrosion-resistant steels obtained by energy-saving rotary friction welding technology

In this article the possibility of application of rotary friction welding for joining parts from stainless steels is evaluated on the example of 10Cr17Ni13Mo2Ti steel. Application of rotary friction welding allows to refuse post-weld heat treatment, which is labor-intensive, energy-consuming and environmentally harmful operation. For this purpose, cylindrical samples of 20 mm in diameter were made from the above steel using friction welding without subsequent heat treatment. The microstructure, microhardness measurement, tensile and impact bending tests were carried out. The microstructure study showed that the weld width across the entire cross-section does not exceed 12 μm. It has an irregular wavy shape with a fine-grained structure. Tensile tests showed that the average value of yield strength of samples with welded joint is 1.6% higher than the same value of samples from the base metal, but the average value of time resistance is lower by 5.6%. Impact bending test results showed that the average impact toughness of welded samples is almost the same as that of base metal samples. According to the results of studies concluded that the weldability of steel 10Cr17Ni13Mo2Ti using friction welding is good, welded joints are obtained high quality.

Adaptive lenticular microlens array based on a transparent electrically responsive fluid

In this work, a focus-tunable lenticular microlens array (LMA) is demonstrated by coating an electro-responsive fluid - Acetyl tributyl citrate (ATBC) onto an in-plane switching (IPS) electrode. ATBC is a transparent liquid that is difficult to hydrolyzed, difficult to ionized, and has a wide working temperature range (-50 ∼ 260 ℃). At initial state, the ATBC film is smooth and flat, and the device has no lensing effect at this time. When a DC electric field is applied, the charge injected from the cathode polarizes the electronegative ATBC molecules and moves them toward the anode region, a wavy shape is formed and the device exhibit LMA lensing effect. After removing the voltage, the ATBC fluid rapidly returns to a flat state. When the voltage reaches 60 V, the focal length can reach as low as ∼ 180 μm. The proposed ATBC liquid lens has high transmittance, good thermal stability, compact structure, which has potential applications in imaging, information processing and 2D/3D displays.

Establishing the reliability of incisive papilla and palatal rugae patterns in individual identification.

The study of palatal rugae forms an important basis of human identification, especially due to mass disasters where routinely used techniques may not be helpful. This study aimed at evaluating the palatal rugae and incisive papilla on the basis of shape. The study was conducted in 280 individuals (males and females) among dental students of Dayananda Sagar College of Dental Sciences. The study included 280 students from Dayananda Sagar College and out-patients from the orthodontics department. Pictures of rugae and the incisive papilla were taken from individuals aged 10-36 using a camera, mirror, and lighting. Two investigators analysed the shape of the rugae and incisive papilla using classification systems by Thomas and Kotze, and Ortman and Tsao, respectively. The data were statistically analysed using SPSS 20.0 software, and a significance level of P ≤ 0.05 was used. The results suggested that rugae showing a wavy shape were the most common pattern in both the genders. Significant differences were observed in the curved rugae type between males and females. In incisive papillae evaluation, the pear shape was the most common, with the triangular shape being the least common. It can be concluded that evaluation of palatal rugae along with the incisive papilla can be an important tool for identification of an individual and for evaluating various ethnic populations.

Information technologies of simulation of beam structures using multispectral spacecraft materials

The work is devoted to solving the scientific and practical task of modeling beam structures based on the materials of multispectral space images based on aerospace and contact measurements. The effectiveness of the use of space survey materials for the study of soil cover largely depends on the time of the survey. The linear forms of erosion (waterholes, ravines) are deciphered on space photographs, which are displayed only on images with a spatial resolution of 1-2 meters in the form of narrow, clearly delineated contours that have a jagged shape.The developed clustering algorithm makes it possible to more clearly identify beam structures on satellite images in combination with data from digital terrain models (DRM). A number of experiments were conducted on some set of remote sensing data of Boryspil and c. Panchevo, Novoukrainsky District, Kirovohrad Region. The experiments consisted in determining the spectral and other features of the beam structures (for example, the shape, soil types, etc.), which are located in different places of the territory that was investigated.On images with a spatial resolution of more than 10 meters, ravines are usually not displayed, but networks of beams with elongated wavy tree-like shapes are clearly visible. In the course of the study, data from multispectral imaging from the Sentinel-2 satellite (MSI scanner) and DEM (Digital Elevation Model, DEM) data obtained through the SRTM 3 archive were used.The research results showed that automating the process of highlighting beam structures on multispectral images with a spatial resolution of 30 m is very difficult. First of all, this can be explained by the fact that the beam consists of vegetation that is also present outside the beam. In addition, the number of channels of the ETM+ scanner and its spatial ability are not enough for a clearer separation of the "beam" class.

Carbon nanotubes@polydopamine/nickel foam with a wavy shape applied for efficient solar-driven seawater desalination

Solar-powered water evaporation has been recognized as a potential water purification regeneration technology to alleviate the issue of global water shortage. Interfacial solar steam generation (ISSG) with a high rate of evaporation and high photo-thermal conversion efficiency is very desirable. Herein, a scalable, high-efficiency and surface tunable ISSG was developed by carbon nanotubes (CNTs) loaded on polydopamine (PDA) modified nickel foam (NF) with a honeycomb three-dimensional (3D) network structure. The surface of CNTs@PDA/NF (CPNF) solar evaporator was designed as the 3D wave-like for further improved water evaporation. The as-prepared solar steam generator has an evaporation rate of 1.61 kg m−2 h−1, and photo-thermal conversion efficiency of 91.0 % at 1.0 solar irradiance. Moreover, it displays efficient purification ability for heavy metal ions in seawater and lake water, and the concentration of Na+, Mg2+, K+ and Ca2+ in the desalinated condensate is in line with the World Health Organization's drinking water standards. Additionally, the dye-contaminated wastewater can also be purified and treated to be drinking water. Furthermore, it has a good salt self-melting function. In sum, this work provides some new insights for designing innovative solar evaporators with outstanding photothermal conversion capability.

The Effect of Leading-Edge Wavy Shape on the Performance of Small-Scale HAWT Rotors

The purpose of this experimental work was to investigate the role of the leading-edge wavy shape technique on the performance of small-scale HAWT fixed-pitch rotor blades operating under off-design conditions. Geometric parameters such as amplitude and wavelength were considered design variables to generate five different wavy shape blade models in order to increase the aerodynamic performance of the rotor with a diameter of 280 mm. A dedicated airfoil type S822 for small wind turbine application from the NREL Airfoil Family was chosen to fulfil both the aerodynamic and structural aspects of the blades. Rotor models were tested in a wind tunnel for different wind speeds while maintaining constant rotational speed to provide the blade-tip chord Reynolds number of 4.7 × 104. The corrected tunnel data, in terms of power coefficients and tip-speed ratios, were compared first with the literature to validate the experimental approach, and then among themselves. It was observed that for minimal sizes of tubercles, the performance of the rotor increases by about 40% compared to the RB1 baseline rotor model for a low tip-speed ratio. Conversely, for the maximum size of the tubercles, there is a marked decrease of about 51% of the rotor performance for a moderate tip-speed ratio compared to the RB1 rotor model. Among these models, specifically, the RB2 rotor model with the smallest values of amplitude and wavelength provides a 2.8% higher peak power coefficient compared to the RB1 rotor model, and at the same time preserves higher performance values for a broad range of tip-speed ratios.