Scale Morphology Research Articles

Ревизия таксономического статуса Mallomonas multiunca var. pocosinensis на основании ультраструктуры кремнеземных покровов клетки, Mallomonas pocosinensis comb. et stat. nov.

The ultrastructure of the silica scales and bristles of two morphologically similar taxa, Mallomonas multiunca var. multiunca and M. multiunca var. pocosinensis, was compared. Based on the revealed differences in the morphology of scales and bristles, the taxonomic status of the species M. multiunca var. pocosinensis was revised and a new taxonomic combination, Mallomonas pocosinensis comb. stat. nov., was proposed. Аn updated description and original SEM micrographs are provided.

A century later: a new species of Mastigoceras Handschin, 1924 (Collembola, Orchesellidae), with morphological and systematic updates on the genus.

Mastigocerascamponoti Handschin, the sole member of its genus and the Mastigocerini tribe, exhibits unusual dorsal chaetotaxy compared to other Orchesellidae. This includes a reduction in dorsal macrochaetotaxy and a secondary covering of fusiform scales intermixed with ciliate microchaetae. Despite three redescriptions, Mastigoceras chaetotaxy remains poorly understood, with no data on tergal sensilla patterns or dorsal macrochaetae homology. Here, the genus is revisited by describing a new Brazilian species a century after the original description of M.camponoti, based on morphological depiction combined with the use of DNA barcoding, Mastigocerashandschini Rodrigues, Souza & Bellini, sp. nov. The two species are differentiated by a few and unusual aspects of the dorsal chaetotaxy, especially scales distribution, and may be considered as pseudocryptic taxa. Our study of tergal sensilla formula, scales morphology, and distribution in Mastigoceras reveals no clear morphological support for placing Mastigocerini within Heteromurinae.

Description of the new species Mallomonas okhapkinii (Synurales, Chrysophyceae) based on morphological and molecular data

This paper describes a new species of Mallomonas discovered in a swamp area in Russia. The species was identified based on scale morphology, examined using scanning and transmission electron microscopy, and subjected to molecular analysis. The new species, Mallomonas okhapkinii sp. nov., belongs to the section Planae and is most similar in scale and bristle ultrastructure to M. matvienkoae sensu stricto. Phylogenetic analysis, performed using a concatenated dataset of nuclear-encoded small subunit rRNA and plastid-encoded rbcL genes, revealed that the strains of the new species form a distinct clade with high statistical support, closely related to the clade of M. paragrandis and M. sorohexareticulata. This species was found in only one habitat.

Water vapor oxidation of SiC layer of tristructural isotropic particles

AbstractTristructural isotropic (TRISO) fuel particles, developed for use in high‐temperature gas‐cooled nuclear reactors, can be subjected to oxidizing environments in off‐normal accident scenarios. In this study, surrogate TRISO fuel particles were oxidized at 1000–1350°C for 4 h in 20 kPa water vapor atmosphere balanced with ultrahigh‐purity helium gas. The oxide scale morphology and thickness were studied via scanning electron microscopy, focused ion beam, and transmission electron microscopy. The oxide thickness increased as the oxidation temperature was increased. Although the oxide scale at 1000°C was completely amorphous, pockets of crystalline oxide were observed on particles oxidized at 1200 and 1300°C. Kinetic analysis was performed to deduce the oxidation mechanism by determining the apparent activation energy using linear regression analysis. The oxidation mechanism was consistent for temperatures from 1000 to 1200°C with an activation energy of 412.4 ± 8.8 kJ/mol. The activation energy then dropped to approximately 201 ± 7.1 kJ/mol for temperatures 1200–1350°C. Therefore, there is a change in oxidation mechanism at ∼1200°C. This change is attributed to the existence of a network of significant bubbles in the oxide layer at higher temperatures, which serve as rapid diffusion pathways for the transport of oxidants from the surface to the SiC/SiO2 interface, instead of relying on the bulk diffusion through the SiO2 layer at lower temperatures where only small bubbles are present along the SiC/SiO2 interface.

Mallomonas enigmata sp. nov. (Synurales, Chrysophyceae), an Eocene fossil species with a second and unique scale morphotype attached to its cyst

ABSTRACT A new and intriguing fossil Mallomonas species, M. enigmata, was uncovered from 10 strata in the Eocene Giraffe Pipe locality. The new species represents an ancient member of the section Punctiferae, and based on scale and bristle morphology is most closely related to the modern congener, M. nieringii. M. nieringii is a rare species known from a suite of acidic waterbodies on the Cape Cod peninsula, Massachusetts, USA. Only a few modifications of the body scales differ between M. enigmata and M. nieringii, and the new taxon was uncovered from a section of the Giraffe Pipe maar lake representing a shallow and acidic waterbody. Cysts of M. enigmata are oval, with a small pore surrounded by a narrow hyaline zone. The anterior ~ ¼ of the cyst surrounding the hyaline zone consists of a series of small, closely spaced, rimmed holes that penetrate the wall. Otherwise, the cyst wall is smooth and unornamented. Unlike any known modern species in the genus, a second type of body scale is produced, but found only attached to the cyst. It is hypothesized that these scales may represent unfinished body scales that became fused to the cyst during its development.

Oxidation Behaviour of TiC/TiN Coatings Deposited by Chemical Vapor Deposition (CVD): Mechanisms, Structures, and Properties

This review explores the oxidation behavior of Titanium Carbide (TiC) and Titanium Nitride (TiN) coatings deposited by Chemical Vapor Deposition (CVD), with a focus on their industrial applications as wear-resistant coatings for cutting tools. It examines effect of process parameters—such as temperature, pressure, precursor composition, and substrate preparation—on formation and performance of TiC/TiN coatings. The review evaluates the microstructural characteristics of these coatings, including crystal structure, using X-ray diffraction analysis. Also, estimates the mechanical properties such as hardness, wear resistance, and adhesion strength. Additionally, the review covers the thermal stability of TiC/TiN coatings, emphasizing their ability to maintain structural integrity at high temperatures, which is essential for the performance of cutting tools and other industrial components. A major focus is the oxidation behavior of TiC/TiN coatings, including the impact of coating composition, deposition methods, and environmental conditions. The review details oxidation kinetics and mechanisms, revealing various stages of oxidation at different temperatures. It also examines oxide scale morphology and its effect on coating properties. Finally, this review reveals the importance of alloying elements, like silicon, in improving oxidation resistance. Composite coatings such as TiSiN and TiSiCN are shown to offer better high-temperature stability compared to traditional TiN coatings. The effects of coating thickness and the benefits of multilayer coatings for enhanced oxidation resistance are also discussed.

Synthesis and evaluation of an environmentally friendly phosphorus-free and nitrogen-free polymer as a scale and corrosion inhibitor

Polyepoxysuccinic acid (PESA) was modified by glycidyl (Gly) to obtain a phosphate-free and nitrogen-free polymer (Gly-PESA), and its scale and corrosion inhibition properties were studied.The effects of Gly-PESA concentration, calcium ion concentration and temperature to scale inhibition performance were studied by static scale inhibition method. The corrosion inhibition performance of Gly-PESA was studied by static weight-loss method. The morphology and structure of calcium scale and steel surface were characterized by spectroscopic and microscopic methods. The scale inhibition efficiency of Gly-PESA for CaCO3 and CaSO4 was 98.06% and 92.6%, respectively. Under the same experimental conditions, the scale inhibition effect of Gly-PESA was obviously better than that of PESA. Gly-PESA could effectively inhibit the growth of CaCO3 and CaSO4 crystals and cause their crystal lattice distortion or crystal dispersion. The corrosion inhibition efficiency of Gly-PESA for carbon steel was 78.17%. The adsorption of Gly-PESA on the surface of the steel test piece followed Langmuir adsorption isotherm, and formed a protective film, which increased the corrosion resistance of the steel test piece, thus effectively protecting the steel test piece. Therefore, Gly-PESA was a green scale and corrosion inhibitor, which solved the problem of environmental pollution.

Influence of Genetic and Non-Genetic Factors on the Physical and Mechanical Properties of Mongolian Cashmere Fiber Properties

Cashmere is widely acclaimed as one of the most luxurious textile fibers. Mongolia, a major player in cashmere production and processing, is key to this industry. Despite the rich history of cashmere, there is limited research on cashmere fiber properties, which are essential in producing high-quality garments. This study aims to improve our understanding of cashmere fibers’ physical and mechanical properties and to assess how genetic and non-genetic factors affect these characteristics. We analyzed key fiber characteristics, including scale morphology, and the physical and mechanical properties (such as fineness, length parameters, stress, and strain) in 11 samples from Mongolian goats of varying areas, breeds, ages, and genders. Through detailed statistical analysis, our experimental results revealed that both genetic and non-genetic factors significantly affect fiber fineness and the specific energy of rupture. Additionally, we observed that the influence of these factors can inform better classification systems for raw cashmere and enhance the determination of the fiber’s spinability limit.

Time dependent anti-corrosion and anti-scaling efficiency of polyepoxysuccinic acid inhibitor in simulated hard water

In this study, the time-dependent performance of a phosphorus-free corrosion and scale inhibitor primarily composed of polyoxyuccinic acid (PESA) and zinc salts was investigated in a laboratory-simulated hard water environment. Long-term static scale inhibition tests and corrosion rotation coupon tests were conducted under two temperature conditions, 45 °C and 80 °C, following established literature standards. Changes in water quality, scale morphology, metal corrosion status, and electrochemical impedance were monitored using calcium ion concentration analysis, optical microscopy imaging, X-ray diffraction (XRD), and electrochemical testing. The study revealed a progressive decline in the corrosion and scale inhibition efficiency of the phosphorus-free inhibitor in simulated hard water with calcium carbonate hardness levels of 300, 400, and 500 mg/L over time. Moreover, higher water hardness accelerated corrosion onset, suggesting that calcium carbonate deposition promotes metal corrosion under the experimental conditions. Density functional theory (DFT) calculations indicated that PESA chemically adsorbs onto both metal and calcite surfaces, underscoring its dual role in corrosion and scale inhibition. These findings underscore the intrinsic corrosion and scale inhibition capabilities of PESA, complementing its synergistic film-forming properties with Zn2+.

Green and sustainable strategies to control scaling in industrial plants: investigation of the efficacy of Rosmarinus officinalis L. Extract against CaCO3 scale using experimental and theoretical approaches

ABSTRACT In recent years, plant extracts have attracted increased interest as green alternatives to conventional anti-scaling. This is because they contain a wide range of bioactive compounds with high performance against inorganic scale. Additionally, they are biodegradable and pose minimal risks to human health and ecosystems. The present study aimed to assess the protection offered by the Rosmarinus officinalis L. leaf extract for industrial plant surfaces against the CaCO3 scale. Before assessing the anti-scaling performance of the Rosmarinus extract, phytochemical characterisation was performed by quantitative assays and HPLC-DAD analysis. Subsequently, the inhibition potential of the extract was studied using the conductivity and LCEE tests at 25°C and TH = 40°f. In addition, SEM and XRD analysis were used to assess the effect of the extract on scale morphology and crystalline phases. Finally, DFT calculations and Monte Carlo simulation were carried out to enhance knowledge of the interaction between inhibitor molecules and CaCO3(104) and (110) surfaces and optimise [extract molecule – Ca]2+ complexes. Phytochemical analysis revealed the presence of several phenolic compounds (rosmarinic acid, vanillic acid, cinnamic acid, rutin, kaempferol, trans chalcone and quercetin). Further LCEE studies demonstrated the promising anti-scaling activity of the extract at an effective concentration of 54 mg/L. SEM micrographs and XRD diffractograms revealed a significant change in the morphology and phases of precipitated CaCO3 scales upon the addition of the inhibitor. In addition, the computational approach strongly supported the experimental results. These results underlined the Rosmarinus extract’s potential as a valuable green and sustainable scaling inhibitor source.

Invited Article: The oxidation kinetics and mechanisms observed during ultra-high temperature oxidation of (HfZrTiTaNb)C and (HfZrTiTaNb)B2

Ultra-high temperature ceramics (UHTCs), most notably transition metal carbides and borides, exhibit melting temperatures exceeding 3000 °C, making them appropriate candidates to withstand the extreme temperatures (∼2000 °C) expected to occur at the leading edges of hypersonic vehicles. However, their propensity to react rapidly with oxygen limits their sustained application. The high entropy paradigm enables the exploration of novel UHTC compositions that may improve on the oxidation resistance of conventional refractory mono-carbides and -diborides. The oxidation kinetics of candidate high entropy group IV + V (HfZrTiTaNb)C and (HfZrTiTaNb)B2 materials were evaluated at 1500–1800 °C using Joule heating in one atmosphere 0.1%–1% oxygen/argon gas mixtures for times up to 15 min. Possible mechanisms based on the resulting complex time, temperature, and oxygen partial pressure dependencies are discussed. The carbides formed porous and intergranular oxides. Oxidation resistance was improved upon a continuous external scale formation. The diborides formed dense external scales and exhibited better oxidation resistance compared to the carbides. This improvement was attributed to the formation of liquid boria. Both compositions showed an unexpected reduction in material consumption at 1800 °C for all times tested, compared to results at lower temperatures. An in-depth analysis of the composition and morphology of the oxide scale and sub-surface regions for specimens tested at 1800 °C revealed that the formation of denser group IV-rich (Hf, Zr, Ti) oxides mitigated the formation of the otherwise detrimental liquid-forming group V (Ta, Nb) oxides, leading to the improved oxidation resistance.

Understanding and controlling chemical clogging in drip irrigation: Integrating experimental methods, density functional theory calculations and molecular dynamics simulations

AbstractThe chemical clogging of water drips is the main obstacle to the adoption and spread of microirrigation technology. The aim of this research is to understand the scaling phenomenon by identifying the substances responsible for emitter clogging using a combination of different methods of characterization and to investigate the effectiveness of a new product ‘Melacide P/2’ as a calcium carbonate scale inhibitor. A non‐electrochemical method from the Laboratory of Chemistry and Genie of the Environment (LCGE) was employed to investigate the effect of the inhibitor against calcium carbonate precipitation at 25°C. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study the effect of Melacide P/2 on the scale morphology and crystalline phases. Density functional theory (DFT) and Monte Carlo (MC) simulations were performed to support the experimental results. Characterization techniques revealed that the scale recovered from the drips consisted mainly of calcium carbonate, a variety of calcite. The experimental data indicate the likelihood of preventing calcium carbonate precipitation after the addition of a very small amount (0.30 mg L⁻¹) of Melacide P/2 under the conditions of the experiment. XRD and SEM revealed that the inhibitor tested has the potential to disrupt or block regular CaCO3 crystal growth and transform a more stable and adherent scale of calcite to aragonite, which is easy to eliminate. The theoretical approach adopted supports the experimental findings. Therefore, Melacide P/2 could be used as a cost‐effective green‐scale inhibitor to protect microirrigation systems from unwanted scale formation.

Scale Characteristics of Six Fish Species of the Genus Cyprinion (Teleostei: Cypriniformes): A Microscopic Analysis.

This study investigated the morphological characteristics of scales in six Cyprinion species, using light and scanning electron microscopy focusing on key features such as scale type, key scales, lateral line scales, radius/radii, rostral margin, focus, circuli, lepidonts, tubercles, and scale indices. The research analyzed the scales using ultramicroscopy and light microscopy imaging, categorizing them based on size classes and body regions. The morphological variations in scale characteristics were examined across different species, regions, and size classes. Notable findings included the tetra-sectioned form of scales, representing a unique characteristic of the Cyprinion genus. Morphological changes in scale features were observed with fish growth, particularly in the overall shape, focus shape, and size. Quantitative analysis revealed variations in average relative scale length and width among different species, regions, and size classes. The study utilized canonical discriminant analysis for multivariate assessment, classifying the species into distinct groups based on morphometric indices. The findings contribute to the understanding of scale morphology in Cyprinion species and exploring morphological variation between the examined species.

High temperature oxidation regime transitions in hafnium carbide

AbstractUnderstanding the oxidation behavior of hafnium carbide is crucial to its application in extreme environments. In this work, the transition in high‐temperature oxidation kinetics regimes in hafnium carbide is explained based on phase equilibria considerations supported by observed changes in oxide scale microstructure evolution associated with different transformation pathways. Below, a composition‐dependent critical temperature and oxygen pressure, hafnium carbide first transforms to an amorphous material with nominal composition HfO2C followed by phase separation into carbon and hafnia domains. Subsequently, gaseous transport through a nanometric pore network formed by oxidative removal of phase‐separated carbon becomes rate‐limiting. Above this critical point, the oxidation sequence involves a direct transformation from hafnium carbide to hafnia and gaseous products, leading to dissimilar scale morphologies responsible for the reported transition from gaseous to solid‐state diffusion‐limited oxidation regimes at ultra‐high temperatures.

Nomenclatural and taxonomic notes on Mallomonas Perty (Chrysophyceae). I. Typification of Mallomonas denticulata Matvienko

Mallomonas denticulata was described by Matvienko in the 1940s, however the ultrastructure of its scales and bristles remained unknown, so the species was considered to be dubious. Mallomonas asmundiae (≡M. cratis var. asmundiae) is a rather rare and widely accepted species but this name is invalid. In this report we discuss the similarity in the scale and bristle morphology between these two species and designate lectotype and epitype for M. denticulata. An emended description is provided.

Mallomonas uralensis sp. nov. (Chrysophyceae, Synurales), a new species of the genus Mallomonas from the section Torquatae

This paper describes a new species of Mallomonas, discovered in small ephemeral waterbodies of Southern Urals (Russia). The species description is based on scale morphology studied using scanning and transmission electron microscopy. Mallomonas uralensis sp. nov. belongs in section Torquatae and is most similar to representatives of the series Mangoferae. The main distinctive features of the new species are papillae and small circular pits located on the surface of the shield; a raised, wide anterior submarginal rib, covered with several parallel rows of minute papillae and surrounded on the outer and inner sides by rows of depressions; narrow anterior flanges bearing one row of minute papillae; and the presence of spines on the most of the body scales.

A Study on Identifying the Spatial Characteristic Factors of Traditional Streets Based on Visitor Perception: Yuanjia Village, Shaanxi Province

The street spaces in tourist-oriented traditional villages served both the daily lives of villagers and the leisure activities of tourists. However, due to insufficient understanding of the spatial characteristics and under-exploration of spatial genes, these spaces often suffered from homogenization during tourism development. Thus, identifying the characteristics and connotations of such streets, understanding the relationship between tourists’ perceptions and built environment elements, and developing optimization strategies for these rural street spaces were urgent issues. Many studies have evaluated street space characteristics from tourists’ behavior, but few have focused on rural areas. Especially, research combining new technologies like artificial intelligence to study the psychological perceptions of tourists is still in its infancy. This study used a typical traditional village as a case study and applied the YOLOv5 deep-learning model to build a perception evaluation system based on three dimensions: tourists’ aggregation degree, stay time, and facial expressions. The study conducted a multivariate regression analysis on 21 factors across 4 aspects: street scale morphology, environmental facilities, ground-floor interface, and street business types. Results indicated that the functional business type of the scene had the greatest impact on tourists’ perception of the street space environment, followed by ground-floor features and environmental facilities. The regression coefficient for business in situ values and spatial perception was 0.47, highlighting it as a key factor influencing characteristic perception. Landscape water systems, flat ground-floor façades, and business diversity also positively affected tourists’ perception. This study utilized advanced techniques like the YOLOv5 model, known for its speed and accuracy, to scientifically analyze tourists’ behavior and perceptions, serving as feedback and evaluation for the village’s built environment. Empirical analysis of Yuanjia Village validated the effectiveness of the multidimensional approach and spatial gene theory. Ultimately, this method identified 12 street characteristic factors significantly affecting tourists’ perceptions. The uniqueness of this study lies in its comprehensive approach, combining empirical research, spatial gene theory, and advanced object detection technology, providing new insights for village spatial planning and construction.

Genomic signatures associated with recurrent scale loss in cyprinid fish.

Scale morphology represents a fundamental feature of fish and a key evolutionary trait underlying fish diversification. Despite frequent and recurrent scale loss throughout fish diversification, comprehensive genome-wide analyses of the genomic signatures associated with scale loss in divergent fish lineages remain scarce. In the current study, we investigated genome-wide signatures, specifically convergent protein-coding gene loss, amino acid substitutions, and cis-regulatory sequence changes, associated with recurrent scale loss in two divergent Cypriniformes lineages based on large-scale genomic, transcriptomic, and epigenetic data. Results demonstrated convergent changes in many genes related to scale formation in divergent scaleless fish lineages, including loss of P/Q-rich scpp genes (e.g. scpp6 and scpp7), accelerated evolution of non-coding elements adjacent to the fgf and fgfr genes, and convergent amino acid changes in genes (e.g. snap29) under relaxed selection. Collectively, these findings highlight the existence of a shared genetic architecture underlying recurrent scale loss in divergent fish lineages, suggesting that evolutionary outcomes may be genetically repeatable and predictable in the convergence of scale loss in fish.

Mallomonas paraperfossa sp. nov. (Chrysophyceae, Synurales), a new species from the shallow ephemeral ponds in the steppe zone of the Southern Urals, Russia

This paper describes a new species of Mallomonas, discovered in small ephemeral waterbodies of the steppe zone of the Southern Urals (Russia). The species description is based on scale morphology studied using scanning and transmission electron microscopy. Mallomonas paraperfossa sp. nov. is most similar to M. perfossa from the section Pseudocoronatae. A comparison was also made with the species M. lelymene and M. sabulosa. The scales of M. paraperfossa are characterized by the presence of rimmed depressions and papillae, randomly located on the shield, and wide and raised anterior flanges with parallel, evenly spaced ribs.

Drag reduction characteristics of the placoid scale array skin sup-ported by micro Stewart mechanism based on penalty immersed boundary method

Sharkskin performs an excellent flow drag reduction property, leading to numerous biomimetic research to obtain artificial drag reduction structures for underwater vehicles. The existing work mainly focused on replicating or simplifying the morphology of the placoid scale, however, such bionic structures cannot fully reproduce the drag reduction effects of sharks swimming in natural environments. This is because the existing research has not considered the influence of the multi-degree freedom motion characteristics of the placoid scale. Therefore, a new bionic drag reduction skin is proposed by combining micro Stewart mechanisms and placoid scales, where the micro Stewart mechanism is able to achieve the multi-degree freedom motion characteristics. The numerical results indicate that micro Stewart mechanisms inhibit the generation and development of the streamwise and spanwise vortex structures in the bionic placoid scale array, which can delay flow separation and improve the drag reduction effect of the placoid scale array. Compared with the bionic placoid scale skin and the blade groove skin without multi-degree freedom motion foundation, the new bionic skin achieves relative drag reduction efficiency of 15.78 % and 14.18 % at maximum, respectively, by reasonably adjusting the bionic skin parameters including the leg stiffness, leg damping, upper platform mass, upper platform center of mass height of the micro Stewart mechanism and the skin element distribution spacing. The research presents a novel sharkskin bionics design and reveals the mechanism of skin drag reduction to some extent.