Base Composition Research Articles

The impact of Si3N4 incorporation on the mechanical characteristics of ZrB2–SiC nanocomposite sintered via pressureless method

Due to their unique properties, ultra-high-temperature ceramics possess have great potential for aerospace and industrial applications. In this study, we utilized ZrB2 and Si3N4 powders in micron scale, along with SiC powder in both nano and micron scale. A nanocomposite comprising ZrB2-20 vol% SiC (15 % nano - 5 % micron)-10 % ZrC was incorporated into the base composition by adding Si3N4 in volumes of 1-2-3 volume and 4 %. The process is carried out by pressure-less sintering at 2150 °C. The evaluation in this study involved X-ray diffraction (XRD) analysis, hardness measurement, density determination, fracture toughness assessment, and bending test. The results showed that addition of Si3N4 enhances the relative density, hardness, and fracture toughness of this nanocomposite. The sample with Si3N4volume fraction of 3 % has the best performance, with a relative density of 99.4 %, a hardness of 20.33 GPa, and a fracture toughness of 3.12 MPa M1/2.

PUSHKIN’S LANGUAGE: LEXICOGRAPHIC STUDIES IV (TOVARISHCH, DRUG OR PRIYATEL?)

t: This publication continues the series of papers devoted to Pushkin’s language. They describe the results of the analysis of the Lexicographic Corpus of Pushkin’s texts created in the Laboratory of General and Computer Lexicology and Lexicography at the Lomonosov Moscow State University’s Faculty of Philology. The article is devoted to the nouns characterizing interpersonal relations from the point of view of proximity of communication. It considers the basic composition, meaning and use of such words in Pushkin’s texts. They are compared with the modern language and with the description given in the Dictionary of the Academy of Russia and Dictionary of Pushkin’s Language. The analysis shows that Pushkin presents a group of units close to the modern one, but not fully coinciding with it. This group includes the now lost or rarely used words drugin’a, znakometz, znakomka, napersnik. The lexical meaning and use of words from this group also have some differences and peculiarities in comparison with the modern language, which should be taken into account when analyzing Pushkin’s texts. They are analyzed and described with the help of examples from these texts. A special attention is paid to the change of the words drug and priyatel. This problem is discussed on the example of Pushkin’s description of Onegin’s relations with Lensky and Onegin’s relations with the author. The analysis has shown that the types of close interpersonal communication are described in the lexical system of Pushkin’s language in more detail than they are now (due to the pair napersnik — napersnitsa), and the word tovarishch marks interpersonal relations to a much lesser extent than its modern counterpart. At the same time, the words znakomyj, drug, priyatel can be considered and used as rather reliable markers of these relations.

Assessment of frequency and amplitude dependence on the cyclic degradation of polyurethane foams

AbstractMany energy absorption applications utilize flexible polymeric foams for their viscoelastic properties. It is desired that the material will perform consistently across repeated compression cycles. This study examines the effect of fatigue at low strain rates on the viscoelasticity of open‐cell polyurethane foam. Six polyurethanes of the same base composition with two porosities (70% and 80%) and three chemical indexes (79i, 100i, and 121i) are tested. Large deformation cyclic compression of the foams is conducted on a universal testing system (UTS). These data are then post‐processed leveraging dynamic mechanical analysis Fourier transform rheology to characterize changes in the viscoelasticity of the materials over fatigue cycles. Results show that foams can increase or decrease in stiffness up to 10% over 104 cycles. Specifically, higher chemical index, higher excitation frequency, and larger excitation amplitude correlate with a more pronounced decrease in stiffness. Damping can also change by 15% and correlates with chemical index and excitation frequency. Consequently, the findings suggest that internal foam structure and bulk material properties as well as applied loading parameters affect the viscoelastic fatigue response of flexible polymeric foams.

Effect of high-pressure-homogenisation on the interaction between pomegranate peel pectin fractions and anthocyanins in acidic environment

In this study, changes in the basic composition and structural characterisation of water-soluble pectin (WSP), homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) from pomegranate peel were investigated after high-pressure-homogenisation (HPH) at 50 MPa and 300 MPa. The interactions between three pectin and anthocyanin (ACN) complex were also studied. The three pectin fractions were mainly composed of galacturonic acid (34.95%–87.69%), all with low degrees of methyl-esterification ≤41.20%. HPH at 300 MPa increased the binding ratios of ACN to three pectin fractions by 34.22%–34.59%. Changes in the structural characterisation results of pectin confirmed that the depolymerisation and breakdown of the side chains of pectin after HPH promoted electrostatic interactions, hydrogen bond and hydrophobic interaction between pectin and ACN. Correspondingly, the thermal and storage stabilities of ACN in the complex was boosted after HPH at 300 MPa. This study provides insights into the interaction between pectin and ACN under HPH.

Structural, Dielectric and Magnetic studies of Mixed Ferrites of Co-Zn using combustion method

Using auto-combustion approach, cobalt ferrite nanoparticles doped with Zn+2 with the basic chemical composition ZnxCo1-xFe2O4 (x = 0 to 1: in steps of 0.25) were prepared. Phase confirmation of the proposed samples was confirmed through XRD studies. XRD pattern of the calcined ferrites revealed single phase spinel cubic structure. At room temperature, using HIOKI LCR meter (Model no: 3520-50) the dielectric measurements in the frequency range 102 Hz–106 Hz were performed. Dielectric constant (ε′) and dielectric loss tangent (tan δ) of synthesized nano-materials were investigated as a function of frequency and Zn+2 concentration at ambient temperature and all the samples exhibited dielectric dispersion. Magnetic measurements for ZnxCo1-xFe2O4 nano-ferrites were carried out at room temperature using a vibrating sample magnetometer (VSM), and all the samples of the system CoZnFe2O4 exhibited ferromagnetic behavior.

ИЗУЧЕНИЕ ПРОЦЕССА СМЕШЕНИЯ ОСНОВНЫХ КОМПОНЕНТОВ АДСОРБИРУЮЩЕГО ГИГИЕНИЧЕСКОГО СРЕДСТВА

The results of research on the study of the mixing process to develop the basic composition of an adsorbent hygienic product for keeping animals and birds in accordance with sanitary standards are presented. The possibility of using a rotary ball mill as the most effective apparatus for grinding and mixing and a turbulent mixer, ensuring high homogeneity when mixing the main ingredients of mixtures, is investigated. In result of studying the processes of mixing the main ingredients in the preparation of an adsorbent hygiene product in various mixing units, an effective basic composition of an adsorbent hygiene product is obtained. Moreover, the components chalk M-5, attapulgite and synthetic amorphous silicon dioxide, obtained by mixing in a turbulent mixer and corresponding to the required specific surface area of 12000 cm2/g, which will provide the necessary sorption capacity and thereby ensure a reduction in pathogenic microflora in places where farm animals and poultry are kept. The developed basis of an adsorbent hygienic powder product, due to its significant specific surface area, will provide a high degree of moisture absorption and create the required level of sanitary and hygienic conditions for keeping animals and birds. Creating a favorable climate for keeping farm animals and poultry will significantly prevent the proliferation of bacteria, which will entail a significant reduction in the consumption of antibiotics when raising farm animals, reduce the level of unpleasant odors, and provide a dry environment for keeping animals and birds

Numerical investigation on the hydrogen removal capability of various catalytic elements in PARs

As an essential part of hydrogen removal system in nuclear power plants, PARs could effectively eliminate released hydrogen and prevent potential hydrogen combustion during severe accidents. Serving as a basic composition in the catalytic section of PARs, catalytic element has a direct influence on the hydrogen removal capability of the PAR device. The CFD software STAR-CCM+ was utilized to develop models of catalytic channels containing three common catalytic elements (including catalytic plates, catalytic cylinders, and catalytic spheres). The elementary reaction mechanism was employed as the reaction kinetics model to define the chemical reaction process. This paper aims to evaluate the hydrogen removal capability of the catalytic elements in same operating conditions and analyze important factors for designing the structure of catalytic elements. All the catalytic surface area of catalytic elements was set to 0.045 m2 and inlet boundary conditions were settled identically. Our findings show that catalytic sphere exhibits the best hydrogen removal capability, which is attributed to the large lower half catalytic surface area of spheres. Catalytic plate with a lower height also demonstrates excellent hydrogen removal capability because of the presence of a larger catalytic area in the leading section. However, the hydrogen removal capability of catalytic cylinder is affected by the boundary layer separation vortex. A noticeable decrease in reaction rate occurs on the lower part of the sidewall surface, especially in the catalytic cylinder with a larger radius. In the structure design of catalytic elements, enlarging the catalytic surface area in the leading section and avoiding boundary layer separation on the catalytic surface are essential to further improve the hydrogen removal capability.

A Review of Orchard Robot Research

In modern agricultural production, orchards, as one of the important agricultural fields, are facing difficulties such as labor shortage, low production efficiency, and rising costs. To cope with these difficulties, orchard robots were introduced as an emerging technology. With the rapid development of robotics, artificial intelligence and machine learning, the application of intelligent robots in the agricultural field is becoming more and more mature. Advances in sensing technology, navigation technology, image recognition and other technologies have provided technical support for the research and application of orchard robots. Through the precise operation of orchard robots, precise management of orchard crops can be realized, including precise fertilization, pest and disease monitoring, directional irrigation, etc., so as to improve the yield and quality of orchards. This increases production efficiency, reduces costs, increases yields, and drives agriculture towards sustainable development. This paper combs the research status of picking robots by combining literature collation and market research, shows the scientific research results of various types of orchard picking robots at home and abroad, makes an in-depth analysis of the existing problems, and discusses the basic system composition of orchard picking robots Existing problems, and propose solutions to the problems found. Orchard picking robot has a huge application space in China, but due to the difficulty of research and development, there are still few economical and practical orchard picking robot products at home and abroad. It is necessary to increase the research and development of intelligent picking robots, integrate multidisciplinary high and new technologies, vigorously carry out innovative research on intelligent picking technology and equipment, improve the precision, portability, and low cost of robots, and promote the early application of orchard picking robots in China.

Research on investment selection of park-level integrated energy system considering electricity-heat-cooling-storage based on matter element extension

The park-level integrated energy system characterized by electricity heat cooling storage is regarded as a viable solution to energy and environmental crises due to its cleanliness and high efficiency. However, decision-makers encounter challenges in picking the optimum construction scheme. The paper introduces the matter element extension into the investment decision-making of the park-level integrated energy system. To begin, the paper analyzes the composition of the evaluation index system from the basic composition of the park-level integrated energy system, and establishes a standard system for comprehensive performance analysis, including economic, environmental, energy, security, and intelligence. Second, the subjective weight is calculated using the fuzzy analytic hierarchy process, the objective weight is calculated using the entropy weight. The matter element extension is used to evaluate the alternatives' performance. Finally, an industrial park in Jiangsu Province of China is selected as a case to verify. The results show that good comprehensive performance can be obtained by using photovoltaic, wind turbines, electric energy storage, ice storage, and heat pumps. The decision-making results will not be affected by the change in subjective and objective weight and the change in index weight within 20 %, but changes in matter-element classification would.

Comparative mitogenomic analysis provides evolutionary insights into Formica (Hymenoptera: Formicidae).

Formica is a large genus in the family Formicidae with high diversity in its distribution, morphology, and physiology. To better understand evolutionary characteristics of Formica, the complete mitochondrial genomes (mitogenomes) of two Formica species were determined and a comparative mitogenomic analysis for this genus was performed. The two newly sequenced Formica mitogenomes each included 37 typical mitochondrial genes and a large non-coding region (putative control region), as observed in other Formica mitogenomes. Base composition, gene order, codon usage, and tRNA secondary structure were well conserved among Formica species, whereas diversity in sequence size and structural characteristics was observed in control regions. We also observed several conserved motifs in the intergenic spacer regions. These conserved genomic features may be related to mitochondrial function and their highly conserved physiological constraints, while the diversity of the control regions may be associated with adaptive evolution among heterogenous habitats. A negative AT-skew value on the majority chain was presented in each of Formica mitogenomes, indicating a reversal of strand asymmetry in base composition. Strong codon usage bias was observed in Formica mitogenomes, which was predominantly determined by nucleotide composition. All 13 mitochondrial protein-coding genes of Formica species exhibited molecular signatures of purifying selection, as indicated by the ratio of non-synonymous substitutions to synonymous substitutions being less than 1 for each protein-coding gene. Phylogenetic analyses based on mitogenomic data obtained fairly consistent phylogenetic relationships, except for two Formica species that had unstable phylogenetic positions, indicating mitogenomic data are useful for constructing phylogenies of ants. Beyond characterizing two additional Formica mitogenomes, this study also provided some key evolutionary insights into Formica.

Effects of Micro- and Nanosilica on the Mechanical and Microstructural Characteristics of Some Special Mortars Made with Recycled Concrete Aggregates.

In this paper, we study the influence of densified microsilica and colloidal nanosilica admixtures on the mechanical strength and the microstructural characteristics of special mortars used for immobilizing radioactive concrete waste. The experimental program focused on the replacement of cement with micro- and/or nanosilica, in different proportions, in the basic composition of a mortar made with recycled aggregates. The technical criteria imposed for such cementitious systems, used for the encapsulation of low-level radioactive waste, imply high fluidity, increased mechanical strength and lack of segregation and of bleeding. We aimed to increase the structural compactness of the mortars by adding micro- and nanosilica, all the while maintaining the technical criteria imposed, to obtain a cement matrix with high durability and increased capacity for immobilizing radionuclides. The samples from all the compositions obtained were analyzed from the point of view of mechanical strength. Also, micro- and nanosilica as well as samples of the optimal mortar compositions were analyzed physically and microstructurally. Experimental data showed that the mortar samples present maximum compressive strength for a content between 6 and 7.5% wt. of microsilica, respectively, for a content of 2.25% wt. nanosilica. The obtained results suggest a synergistic effect of micro- and nanosilica when they are used simultaneously in cementitious compositions. Thus, among the analyzed compositional variants, the mortar composition with 3% wt. microsilica and 2.25% wt. nanosilica showed the best performance, with an increase in compressive strength of 23.5% compared to the control sample (without micro- and nanosilica). Brunauer-Emmett-Teller (BET) analysis and scanning electron microscopy (SEM) images highlighted the decrease in pore diameter and the increase in structural compactness, especially for mortar samples with nanosilica content or a mixture of micro- and nanosilica. This study is useful in the field of recycling radioactive concrete resulting from the decommissioning of nuclear research or nuclear power reactors.

Ablation Resistance of ZrB2-SiC-Si Composite Coatings Applied on Graphite Substrate by Spark Plasma Sintering

In this research, a protective composite coating made of ultra-high-temperature ceramics (UHTCs) was applied on the graphite substrate to boost the ablation resistance of the graphite substrate. Spark plasma sintering (SPS) was used to create such coatings on the graphite substrates. Efforts were made to identify the appropriate chemical composition for the composite coating and the conditions for the SPS (temperature, pressure and holding time). The coatings with a base composition of ZrB2-15 vol.% Si-15 vol.% SiC as well as MoSi2 and WC additives in the same amounts of 0 vol.%, 2.5 vol.% and 5 vol.% of each were applied on the graphite substrates under sintering conditions of final temperature of 1875 ± 25°C, initial pressure of 10 MPa, final load of 25 MPa and holding time of 5 min. The results obtained from the ablation test by oxyacetylene flame verified that the presence of the protective composite coating significantly increases the ablation performance of the graphite substrate. The sample without WC and MoSi2 additives had the lowest mass reduction in longer ablation times, which indicates the high ablation resistance of the base sample compared to the samples with those additives.

Phylogenetic analysis of Cyprinus acutidorsalis (Wang, 1979) from the Hainan population using complete mitochondrial genome

Cyprinus acutidorsalis (Wang, 1979) is an endemic fish in China that is sparsely distributed in the Hainan provinces and Guangxi Zhuang Autonomous Region (GZAR). In this study, the complete mitochondrial genome of C. acutidorsalis from the Hainan population from the Wanquan River was sequenced, and its phylogenetic relationship was analyzed. The circular mtDNA was 16,581 bp in length, and the overall base composition was A (32.0%), C (27.5%), T (24.8%), and G (15.70%), with a slight bias toward A + T. The complete mitogenome encoded 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a control region. Phylogenetic analysis indicated that the most closely related fish to C. acutidorsalis from the Hainan population was C. acutidorsalis from the Guangxi population. These findings offer basic molecular data and a better understanding of the phylogenetic relationships among the Cyprinus species.

The mitochondrial genome of Homoneura picta (Diptera: Lauxaniidae) and its phylogenetic analysis

Homoneura picta belongs to the Homoneurinae subfamily of Lauxaniidae, and it is widely distributed and common in China. This study reports the newly sequenced mitochondrial genome of H. picta. The sequence is 15,469 bp long and contains 37 genes (13 protein-coding, 22 tRNA, and 2 rRNA genes) and a control region. The overall base composition is 38.4% for A, 37.7% for T, 14.1% for C, and 9.8% for G, with a bias toward A + T (76.1%). Phylogenetic analysis show that Homoneura is a sister genus of Cestrotus. We have successfully sequenced the mitochondrial genome of H. picta, which can be useful in investigating the phylogenetic status of Homoneurinae. Our results provide data for further studies of phylogeny in Diptera.

The complete mitochondrial genome of Trematomus hansoni Boulenger, 1902 (Perciformes, Nototheniidae)

The striped notothen Trematomus hansoni is an Antarctic fish species belonging to the family Nototheniidae (cod icefishes) that is distributed throughout the Southern Ocean. In this study, the complete mitochondrial genome of T. hansoni was sequenced using an Illumina MiSeq platform. The circular mitochondrial genome is 19,218 bp long and contains 13 protein-coding genes, 23 tRNA genes, two rRNA genes, and one control region. Notably, there are two trnG-UCC genes and the second gene, located between trnE-UUC and trnI-GAU, has no D-arm structure. The base composition is 56.18% of A + T and 43.82% of G + C. The phylogenetic analysis supports that T. hansoni is grouped into a single clade with T. bernacchii. This study will be a valuable resource for further research on the phylogeny and evolution of the genus Trematomus.

The complete mitochondrial genome of Anidiocerus bimaculatus Zhang, Li & Qi, 2008 (Hemiptera: Cicadellidae: Eurymelinae: Idiocerini)

In this study, the complete mitochondrial genome of Anidiocerus bimaculatus was sequenced and annotated for the first time, which belongs to the subfamily Eurymelinae. The mitogenome of A. bimaculatus was 15,267 bp in length and contained 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and one non-coding control region. In this mitogenome, all the PCGs are initially encoded by ATT, ATA, ATG, or TTG, and terminated by TAA, or single T. The overall base composition of A. bimaculatus is 43.6% adenines, 36.0% thymines, 9.1% guanines, and 11.3% cytosines. ML phylogenetic analyses confirmed that Idiocerini forms a monophyletic clade and the newly sequenced A. bimaculatus clustered within the Idiocerini clade based on 13 protein-coding genes and two rRNA genes.

Complete mitochondrial genome of the worm snail Thylacodes adamsii (Littorinimorpha: Vermetidae) from South Korea

The worm snail Thylacodes adamsii (Mörch, 1859) (Littorinimorpha: Vermetidae) is a sessile gastropod that mainly inhabits rocky shores along the warm temperate to tropical ocean. Herein, the complete mitochondrial genome (mitogenome) of T. adamsii from South Korea was characterized. The genome is 14,913 bp in length and contains 13 protein-coding genes (PCGs), 22 tRNA genes, and 2 rRNA genes. The genome organization and base composition of T. adamsii are similar to those of other vermetids. A phylogenetic tree was reconstructed using maximum likelihood based on the nucleotide sequences of the 13 PCGs; this tree supported the monophyly of Vermetidae. The complete mitogenome of T. adamsii can assist with molecular species identification and vermetid phylogenetic research in the future.

Assembly and comparative analysis of the complete mitochondrial genome of Brassica rapa var. Purpuraria

BackgroundPurple flowering stalk (Brassica rapa var. purpuraria) is a widely cultivated plant with high nutritional and medicinal value and exhibiting strong adaptability during growing. Mitochondrial (mt) play important role in plant cells for energy production, developing with an independent genetic system. Therefore, it is meaningful to assemble and annotate the functions for the mt genome of plants independently. Though there have been several reports referring the mt genome of in Brassica species, the genome of mt in B. rapa var. purpuraria and its functional gene variations when compared to its closely related species has not yet been addressed.ResultsThe mt genome of B. rapa var. purpuraria was assembled through the Illumina and Nanopore sequencing platforms, which revealed a length of 219,775 bp with a typical circular structure. The base composition of the whole B. rapa var. purpuraria mt genome revealed A (27.45%), T (27.31%), C (22.91%), and G (22.32%). 59 functional genes, composing of 33 protein-coding genes (PCGs), 23 tRNA genes, and 3 rRNA genes, were annotated. The sequence repeats, codon usage, RNA editing, nucleotide diversity and gene transfer between the cp genome and mt genome were examined in the B. rapa var. purpuraria mt genome. Phylogenetic analysis show that B. rapa var. Purpuraria was closely related to B. rapa subsp. Oleifera and B. juncea. Ka/Ks analysis reflected that most of the PCGs in the B. rapa var. Purpuraria were negatively selected, illustrating that those mt genes were conserved during evolution.ConclusionsThe results of our findings provide valuable information on the B.rapa var. Purpuraria genome, which might facilitate molecular breeding, genetic variation and evolutionary researches for Brassica species in the future.

Characterization and optimisation of physical/mechanical properties of aluminium/alumina/sugarcane‐bagasse‐powder composites using Taguchi technique

AbstractBurnt sugarcane bagasse powder (SCBP), with its low density, accessibility, and renewal, is an economically reinforcing material. This study fabricated composites, i. e., aluminium/alumina/burnt sugarcane bagasse powder, through the powder metallurgy route. The physical, mechanical, microscopic, and chemical characterization of the composites, such as relative density, microhardness, uniaxial compression, scanning electron microscopy, and x‐ray diffraction, has been conducted. There is a gain in relative density, microhardness and ultimate compression strength of about 2.25 %, 48.07 % and 33.34 % respectively, compared to the base composite (aluminium/4 wt.‐% alumina) at 3 wt.‐% burnt sugarcane bagasse powder. The Taguchi methodology is used as a statistical tool to optimise the response variables. An analysis of variance (ANOVA) is used to find the contribution of input parameters to response variables, and the regression models have been developed. The contribution of factors ‘burnt sugarcane bagasse powder wt.‐%’ and ‘time’ on relative density is 81.65 % and 13.64 %, respectively, while the contribution of the same factors on microhardness is 95.98 % and 3.377 %, respectively. The results of the Taguchi method reveal that the optimised conditions for the highest relative density and microhardness are 3 wt.‐% burnt sugarcane bagasse powder and 2.5 h, which have confirmed the experimental results.

Organoclay application in the tire tread base composite

Organoclay application in the tire tread base composite