Scale Layer Research Articles

Target Tracking Based on Correlation Filter for Scale Offset

Existing scale estimation methods mainly use fixed-size tracking box for target tracking. However, when the moving direction of the target changes from near to far or from far to near, the size of the current tracking box cannot adapt to the scale change. In order to overcome the disadvantage of invariant size of tracking box in the scale change, this paper proposes a scale offset estimation method based on correlation filter by combining the state of previous frame and current frame of the target. Select the scale proposal box in the scale layer, and adjust the position and size of the actual tracking box in real time according to the size of the proposal box, target position and scale offset. In this paper, OTB-100 is used as the dataset. The obtained tracking results show that our algorithm Ours has better tracking performance than the existing others tracking algorithm in scale variation, and it has better tracking effect and stronger robustness in drift and occlusion events.

Unprecedented oxidation resistance at 900 °C of Mo–Si–B composite with addition of ZrB2

The oxidation behavior of Mo–12Si-8.5B and Mo–12Si-8.5B–ZrB2 composites was studied at 900 °C in air. The Mo–12Si-8.5B composite, presented the significant weight loss of 180 mg/cm2 during oxidation for 30 h at this low temperature. This was largely attributed to the formation of low viscosity borosilicate glass scale on its surface, which allowed the continuous evaporation of MoO3. However, such degree of significant oxidation was controlled dramatically by the addition of ZrB2 to the Mo–12Si-8.5B and it further significantly improved the oxidation resistance of the composite. In particular, the Mo–12Si-8.5B–ZrB2 composite presented the small weight gain of 10 mg/cm2 after oxidation for 30 h; moreover the oxidation trend of Mo–12Si-8.5B–ZrB2 was stable and its behavior was opposed to that of the ZrB2-free composite. In addition, the drastically decreased thicknesses of the silicate scale and internal oxide layer were observed in the ZrB2-contained composite. Owing to the addition of ZrB2, which increased the viscosity of the silica glass, a protective Zr-rich silicate glass scale formed and passivated the composite against further oxidation. This was supplemented by the ZrO2/ZrSiO4 products that further prevented the Mo or Mo oxides from evaporating and hindered the inward diffusion of oxygen.

Thoracic scales of moths as a stealth coating against bat biosonar.

Many moths are endowed with ultrasound-sensitive ears that serve the detection and evasion of echolocating bats. Moths lacking such ears could still gain protection from bat biosonar by using stealth acoustic camouflage, absorbing sound waves rather than reflecting them back as echoes. The thorax of a moth is bulky and hence acoustically highly reflective. This renders it an obvious target for any bat. Much of the thorax of moths is covered in hair-like scales, the layout of which is remarkably similar in structure and arrangement to natural fibrous materials commonly used in sound insulation. Despite this structural similarity, the effect of thorax scales on moth echoes has never been characterized. Here, we test whether and how moth thorax scales function as an acoustic absorber. From tomographic echo images, we find that the thin layer of thoracic scales of diurnal butterflies affects the strength of ultrasound echoes from the thorax very little, while the thorax scales of earless moths absorbs an average of 67 ± 9% of impinging ultrasonic sound energy. We show that the thorax scales of moths provide acoustic camouflage by acting as broadband (20-160 kHz) stealth coating. Modelling results suggest the scales are acting as a porous sound absorber; however, the thorax scales of moths achieve a considerably higher absorption than technical fibrous porous absorbers with the same structural parameters. Such scales, despite being thin and lightweight, constitute a broadband, multidirectional and efficient ultrasound absorber that reduces the moths' detectability to hunting bats and gives them a survival advantage.

Scaling Resistance in Nanophotonics-Enabled Solar Membrane Distillation.

This study compares the scaling behavior of membrane distillation (MD) with that of nanophotonics-enabled solar membrane distillation (NESMD). Previous research has shown that NESMD, due to its localized surface heating driven by photothermal membrane coatings, is an energy-efficient system for off-grid desalination; however, concerns remained regarding the scaling behavior of self-heating surfaces. In this work, bench-scale experiments were performed, using model brackish water, to compare the scaling propensity of NESMD with MD. The results showed NESMD to be highly resistant to scaling; a three times higher salt concentration factor (c/c0) was achieved in NESMD compared to MD without any decline in flux. Analyses of the scaling layer on NESMD membranes revealed that salt deposition was 1/4 of that observed for MD. Scaling resistance in NESMD is attributed to its lower operating temperature, which increases the solubility of common scalants and decreases salt precipitation rates. Precipitation kinetics measurements revealed an order of magnitude faster precipitation under heated conditions (62 °C, k = 8.7 × 10-2 s-1) compared to ambient temperature (22 °C, k = 7.1 × 10-3 s-1). These results demonstrate a distinct advantage of NESMD over MD for the treatment of high scaling potential water, where scaling is a barrier to high water recovery.

Influence of Injection Distance on Water Droplet Behavior in High Pressure Descaling

Hydraulic descaling is used in hot rolling mills in order to remove scale and prevent surface defects. Because the impact pressure of the descaling jet is one important factor from the viewpoint of mechanical breaking and applying thermal shock to scale layers, the water jet structure and the droplet velocity should have large effects on scale breaking properties. However, the influence of the injection distance on the jet structure and the droplet velocity has not been clearly understood. In this work, the behavior of changes in the descaling jet structure and attenuation of the water droplet velocity along the injection distance were investigated experimentally. High pressure descaling nozzles with pressures up to 25 MPa were used, and the injection distance was varied in the range from 30 to 400 mm. The jet structure was observed with a high speed camera, and the water droplet velocity and diameter were measured with a phase Doppler analyzer. The results confirmed that the jet structure changes continuously through a process of continuous flow, break-up, water lumps, and water droplets. It was found that a continuous flow can be maintained for a long distance by using a low injection pressure and large flow rate, and the water droplet diameter also becomes larger, which reduces velocity attenuation. These deformation properties of the jet structure are related to the Weber number expressed by the relative velocity between a water droplet and the surrounding air. A smaller Weber number is effective for reducing velocity attenuation over a long injection distance.

The moth specialist spider Cyrtarachne akirai uses prey scales to increase adhesion.

Contaminants decrease adhesive strength by interfering with substrate contact. Spider webs adhering to moths present an ideal model to investigate how natural adhesives overcome contamination because moths' sacrificial layer of scales rubs off on sticky silk, facilitating escape. However, Cyrtarachninae spiders have evolved gluey capture threads that adhere well to moths. Cyrtarachne capture threads contain large glue droplets oversaturated with water, readily flowing but also prone to drying out. Here, we compare the spreading and adhesion of Cyrtarachne akirai glue on intact mothwings, denuded cuticle and glass to the glue of a common orb-weaving spider, Larinioides cornutus, to understand how C. akirai glue overcomes dirty surfaces. Videos show that C. akirai's glue spreading accelerates along the underlying moth cuticle after the glue seeps beneath the moth scales-not seen on denuded cuticle or hydrophilic glass. Larinioides cornutus glue droplets failed to penetrate the moth scales, their force of adhesion thus limited by the strength of attachment of scales to the cuticle. The large size and low viscosity of C. akirai glue droplets function together to use the three-dimensional topography of the moth's scales against itself via capillary forces. Infrared spectroscopy shows C. akirai glue droplets readily lose free-flowing water. We hypothesize that this loss of water leads to increased viscosity during spreading, increasing cohesive forces during pull-off. This glue's two-phase behaviour shows how natural selection can leverage a defensive specialization of prey against themselves and highlights a new design principle for synthetic adhesives for adhering to troublesome surfaces.

Anticorrosion Behaviour of Calcareous Deposits Formed on Steel Heat‐Exchange Surfaces

A new electrode to study both scaling and corrosion processes of mild steel in tap water was developed. Two identical steel rings are placed on the outside of a glass tube which is heated from inside with an electric spiral; the rings are connected to a corrometer to form a two‐electrode corrosion probe. The corrosion rate variations with scale thickness, scale deposition time, and solution composition are measured using the linear polarization resistance technique. The deposited scale was formed of calcite crystals of 50–100 μm as established with SEM and XRD. The scale layer of 0.2 mm formed in tap water within 90 hours reduces the steel corrosion rate from 0.8 to 0.1 mm/year and serves as a barrier layer to prevent further corrosion.

Effect of SiC and WC additon on Oxidation Behavior of Spark-Plasma-Sintered ZrB<sub>2</sub>

ZrB2 ceramic and ZrB2 ceramic composites with the addition of SiC, WC, and SiC/WC are successfully synthesized by a spark plasma sintering method. During high-temperature oxidation, SiC additive form a SiO2 amorphous outer scale layer and SiC-deplete ZrO2 scale layer, which decrease the oxidation rate. WC addition forms WO3 during the oxidation process to result in a ZrO2/WO3 liquid sintering layer, which is known to improve the antioxidation effect. The addition of SiC and WC to ZrB2 reduces the oxygen effective diffusivity by one-fifth of that of ZrB2. The addition of both SiC and WC shows the formation of a SiO2 outer dense glass layer and ZrO2/WO3 layer so that the anti-oxidation effect is improved three times as much as that of ZrB2. Therefore, SiC- and WC-added ZrB2 has a lower two-order oxygen effective diffusivity than ZrB2; it improves the anti-oxidation performance 3 times as much as that of ZrB2.

Study shows thicker hair isn’t necessarily stronger

Keratin-based biomaterials that mimic the properties of hair, which is tough and strong for its weight, could one day be used in medical devices or cosmetics. But to accomplish that, scientists will need to replicate the internal structure of hair and the way individual structural elements bond to one another. A hair consists of bundles of keratin fibers connected by chemical bonds and surrounded by layers of scales called cuticles. A team led by Robert O. Ritchie at the University of California, Berkeley, and Marc A. Meyers at the University of California San Diego found that these elements interact differently in various types of hair (Matter 2019, DOI: 10.1016/j.matt.2019.09.019). The team collected hair from several mammal species, including humans, and pulled strands until they broke. The researchers examined the broken ends with scanning electron microscopy. They found that thin hair, such as human hair, tends to break in long cracks,

Distinct Behaviors between Gypsum and Silica Scaling in Membrane Distillation.

Mineral scaling constrains membrane distillation (MD) and limits its application in treating hypersaline wastewater. Addressing this challenge requires enhanced fundamental understanding of the scaling phenomenon. However, MD scaling with different types of scalants may have distinctive mechanisms and consequences which have not been systematically investigated in the literature. In this work, we compared gypsum and silica scaling in MD and demonstrated that gypsum scaling caused earlier water flux decline and induced membrane wetting that was not observed in silica scaling. Microscopic imaging and elemental mapping revealed contrasting scale morphology and distribution for gypsum and silica, respectively. Notably, while gypsum crystals grew both on the membrane surface and deep in the membrane matrix, silica only formed on the membrane surface in the form of a relatively thin film composed of connected submicrometer silica particles. We attribute the intrusion of gypsum into membrane pores to the crystallization pressure as a result of rapid, oriented crystal growth, which leads to pore deformation and the subsequent membrane wetting. In contrast, the silica scale layer was formed via polymerization of silicic acid and gelation of silica particles, which were less intrusive and had a milder effect on membrane pore structure. This hypothesis was supported by the result of tensile testing, which showed that the MD membrane was significantly weakened by gypsum scaling. The fact that different scaling mechanisms could yield different consequences on membrane performance provides valuable insights for the future development of cost-effective strategies for scaling control.

On the Strength of Hair across Species

Summary The hair of mammals varies in diameter across species from ∼60 μm in humans to over ∼400 μm in giraffes and elephants. Here, we establish that the tensile strength of hair generally decreases with increasing diameter. Although there is a commonality in the morphology of the hair in such differing species as they all possess a cortex surrounded by cuticles, there are also significant differences in the hierarchical structure that contribute to the observed differences in strength. In this work, the internal structure of the hair from different species is examined, with some unique peculiarities in javelina and capybara hair uncovered. The dimensional dependence of hair strength is compared using Weibull predictions. The good correlation of the strength of hair using such Weibull analysis suggests that the failure strength is dictated by the probability distribution of flaws within the cortex.

New insights into the application of microbial desalination cells for desalination and bioelectricity generation

Microbial desalination cell (MDC) is considered as a cost-effective substitution to the present energy-intensive desalination methods. Transfer of salt ions through ion exchange membranes towards the counter electrodes takes place through the utilization of self-generated bioelectricity and the concentration gradient. Ions transportation is one of the main challenges faced in MDCs to which less attention has been paid during the course of development. Therefore, new insights into the application of MDCs for efficient utilization of the generated bioelectricity for desalination are of high demand. In light of this, the present research thoroughly investigated the behavior of ions transportation and bioelectricity generation in three MDCs using three different salt solutions; NaCl, synthetic and artificial seawater. The findings obtained suggested that the efficiency of ions transportation and fouling behavior were influenced by salt compositions and concentration of the salt solution. Multivalent ions (i.e. Mg2+, Ca2+, and PO43-) were found more prone to precipitation on the CEM forming a scaling layer, whereas, inorganic deposition and biofouling development were more likely to happen on the AEM. This study also confirmed the occurrence of a significant back diffusion of K+ from catholyte into desalination chamber. Such back diffusion could limit the use of potassium buffer in catholyte in real-scale applications. Moreover, the coefficients of salt transfer and ion diffusion were calculated using mathematical model and Excel solver in three running MDCs. Low salt transfer and ion diffusion coefficients values obtained for all three MDCs could explain the general low performance of MDCs. Further studies are required to optimize the salt transfer and ion diffusion coefficients to boost MDC performance in general; affecting their real-scale implementation.

Velocity-defect laws, log law and logarithmic friction law in the convective atmospheric boundary layer

The mean velocity profile in the convective atmospheric boundary layer (CBL) is derived analytically. The shear-stress budget equations and the mean momentum equations are employed in the derivation. The multi-point Monin–Obukhov similarity (MMO) recently proposed and analytically derived by Tong & Nguyen (J. Atmos. Sci., vol. 72, 2015, pp. 4337–4348) and Tong & Ding (J. Fluid Mech., vol. 864, 2019, pp. 640–669) provides the scaling properties of the statistics in the shear-stress budget equations. Our previous and present studies have shown that the CBL is mathematically a singular perturbation problem. Therefore, we obtain the mean velocity profile using the method of matched asymptotic expansions. Three scaling layers are identified: the outer layer, which includes the mixed layer, the inner-outer layer and the inner-inner layer, which includes the roughness layer. There are two overlapping layers, the local-free-convection layer and the log layer, respectively. Two new velocity-defect laws are discovered: the mixed-layer velocity-defect law and the surface-layer velocity-defect law. The local-free-convection mean profile is obtained by asymptotically matching the expansions in the first two layers. The log law is obtained by matching the expansions in the last two layers. The von Karman constant is obtained using velocity and length scales, and therefore has a physical interpretation. A new friction law, the convective logarithmic friction law, is obtained. The present work provides an analytical derivation of the mean velocity profile hypothesized in the Monin–Obukhov similarity theory, and is part of a comprehensive derivation of the MMO scaling from first principles.

Deep Feature-Based Multitask Joint Sparse Representation for Hyperspectral Image Classification

Deep multiscale features extracted from diverse perspectives present a more powerful ability than shallow ones for hyperspectral image (HIS) classification. In this letter, we proposed a deep feature-based multitask joint sparse representation (D-MJSR) method. First, filter banks transferred from the pretrained VGG16 network are utilized to extract multiscale features of HSI. Then, features from each scale layer are respectively and collaboratively fused with the raw spectral feature and then upsampled by bilinear interpolation to reach the input size. Finally, with the advantages of feature distribution at different scales, JSR under multitask dictionaries is introduced to achieve the final classification, where samples are represented by dictionaries with different scale spaces independently, and neighborhood samples in each scale are represented by the same atoms wherever possible. We evaluate the proposed method D-MJSR by two public hyperspectral data sets quantitatively. Compared with existing feature extraction and SR-based methods, our method presents some significant improvement in classification accuracy.

Efficiency of Layer’s Supply Chains in Indonesia

Research on the efficiency of egg’s supply chain focused on various markets is expected to provide input to maintain the existence of small scale layers’ farming. This study aim is to analyze the efficiency of supply chain of small-scale layers’ farming. This research is conducted in April-October 2017 in Blitar Regency, in East Java; Sidrap Regency, in South Sulawesi; and Kabupaten 50 Kota, in Payakumbuh City and Pariaman Regency, in West Sumatra. The number of respondents used are 139 people consisting of officers in related institutions, poultry shop entrepreneurs, traders, breeders association farmers, supermarket managers, hotels, restaurants and caterings. The data collected is analyzed using the Data Envelopment Analysis (DEA). The results concludes that traders naturally seek efficient supply chains so that their business can be endured. Factors that influence supply chain efficiency are share farmer, profit and marketing cost ratio, and number of actors involved. The higher the farmer share, and the profit-to-cost ratio, and the fewer marketing channel in a supply chain, the more efficient the supply chain system. Large capital farmers are advised to be able to shorten the supply chain by marketing directly to consumers such as hotels, supermarkets, restaurants, hospitals and caterings. The egg supply chain can also utilize the Indonesian Farmer Shop (TTI) developed by the Ministry of Agriculture so that it can increase farmer’s income and stabilize prices.

Investigating the effect of temperature on calcium sulfate scaling of reverse osmosis membranes using FTIR, SEM-EDX and multivariate analysis

Membrane fouling is one of the major hurdles in widespread use of seawater reverse osmosis (SWRO) in desalination industry. There are various factors that affect the inorganic fouling or scaling of Reverse osmosis (RO) membranes. In this research, the effect of temperature on scaling of RO and Graphene oxide (GO) coated RO membrane by calcium sulfate was investigated. It was found that the increase in temperature enhanced the membrane scaling which was evident by the severe flux decline over time leading to increase in mass of crystals precipitated (Mt) and thickness of the scale layer. There was strong positive correlation (R2 ≥ 0.97) noted between Mt and the temperature. The results of SEM-EDX and XRD confirmed that the crystals formed under the experimental conditions are gypsum. Results of this research showed that there was no significant difference in terms of crystal morphology, scaling intensity and mechanism after modifying RO membrane with GO. It was noted that the morphology of the crystals varied from rod shaped to rosette structures under the influence of temperature. Furthermore, the results of FTIR helped to understand the mechanism of interaction between the membranes and the gypsum. The hydrophilicity of the scaled membrane was also measured to investigate the changes in the properties of the membrane after scaling.

Three New Freshwater Cochliopodium Species (Himatismenida, Amoebozoa) from the Southeastern United States.

Cochliopodium is a lens-shaped genus of Amoebozoa characterized by a flexible layer of microscopic dorsal scales. Recent taxonomic and molecular studies reported cryptic diversity in this group and suggested that the often-used scale morphology is not a reliable character for species delineation in the genus. Here, we described three freshwater Cochliopodium spp. from the southeastern United States based on morphological, immunocytochemistry (ICC), and molecular data. A maximum-likelihood phylogenetic analysis and pairwise comparison of COI sequences of Cochliopodium species showed that each of these monoclonal cultures were genetically distinct from each other and any described species with molecular data. Two of the new isolates, "crystal UK-YT2" (Cochliopodium crystalli n. sp.) and "crystal-like UK-YT3" (C.jaguari n. sp.), formed a clade with C.larifeili, which all share a prominent microtubule organizing center (MTOC) and have cubical-shaped crystals. The "Marrs Spring UK-YT4" isolate, C.marrii n. sp., was 100% identical to "Cochliopodium sp. SG-2014 KJ569724." These sequences formed a clade with C.actinophorum and C.arabianum. While the new isolates can be separated morphologically, most of the taxonomic features used in the group show plasticity; therefore, Cochliopodium species can only be reliably identified with the help of molecular data.

Feasibility of osmotic dilution for recycling spent dialysate: Process performance, scaling, and economic evaluation

Hemodialysis is one of the therapies for patients with kidney failure. Hemodialysis requires large amounts of pure water, and is one of the most water-hungry medical procedures, and thus represents a clear opportunity where improvements should be made concerning the consumption and wastage of water. In this paper, we explored the potential of forward osmosis (FO) membrane for recycling the spent dialysate using the dialysis concentrate as the draw solution. Partially diluted dialysis concentrate could be further diluted with pure water to form dialysate for further dialysis process. Using commercial cellulose triacetate (CTA) FO membranes, the water recovery of approximately 64% was achieved and the final volume of the partially diluted dialysis concentrate was about four times the initial volume. Flux decline of the FO process was observed, mainly due to concentration of synthetic spent dialysate and dilution of dialysis concentrate, while membrane scaling had little impact on the flux decline. The urea rejection was found to be relatively low owing to the small size and electroneutral nature of the urea molecule. Obvious membrane scaling was observed after three FO cycles. The energy dispersive spectroscopy analysis of the scaling layer indicated that the scalants were phosphates and carbonates. The scaling was removed via osmotic backwash and almost completely recovery of FO flux was obtained. Economic analysis showed that the centralized treatment of spent dialysate in a dialysis center using the proposed osmotic dilution process could greatly save water resources and cost. Improving the urea rejection of FO membrane was identified as an important research focus for future research on the potential application of FO technology for recycling the spent dialysate in hemodialysis.

Microstructure of Ni-Cr-Based Coating for Corrosive Conditions

The present study was done to investigate the microstructure and erosion–corrosion behavior of Inconel 625 coating. 270 µm thick coating was successfully deposited on alloy-76 with cold spray coating process, and from microstructure analysis, it is found that coating is dense, smooth and hard with porosity less than 1%. Surface porosity was further reduced to less than 0.5% by burnishing process. Corrosive tests were performed in the actual working plant of medical waste incinerator for 10 cycles of total 1000 h at 900 °C. Coated samples performed better as compared to bare alloy mainly because of formation of chromia-rich protective surface scale layer which had resisted the penetration of corrosive species toward the substrate. Erosion–corrosion rates in mils per year (mpy) are 108.29, 43.45 and 30.69 for bare alloy-76, Inconel 625 coated and burnished-625 coated alloy-76, respectively. Active oxidation mechanism has been noticed in case of bare alloy in corrosive incinerator environment. Cold spray coated Inconel 625 microstructure is suitable for application in erosive–corrosive high temperature environment.

Silica fouling during groundwater RO treatment: The effect of colloids’ radius of curvature on dissolution and polymerisation

Silica fouling during groundwater reverse osmosis (RO) treatment can have a significant impact on filtration performance. To better understand this phenomenon, the equilibrium kinetics of amorphous colloidal silica were studied at conditions relevant to RO of silica-rich alkaline groundwater. The impact of particle size was investigated using synthetic monodisperse silica nanoparticles. Bench scale experiments were conducted by monitoring dissolved silica concentration of aqueous suspensions of colloids of 100 and 300 nm diameter and pH 8.5 to 9.5. The equilibrium data was determined from existing established rate law equations. This study concluded that surface energy has a major impact on silica dissolution rate constant, particularly for colloidal silica. Observations of Ostwald ripening in bidisperse silica dispersions further confirmed these results, which indicate that dissolution and redeposition is responsible for the problematic silica fouling behaviour during RO treatment. 2D modelling based on inferred equilibrium data allows visualization of scale layer growth in agreement with cross-sectional scanning electron micrographs of autopsied membranes.