Cohesive Characteristics Research Articles

Neighborhood social cohesion and sleep health among sexual minoritized US adults and intersections with sex/gender, race/ethnicity, and age

ObjectivesNeighborhood social cohesion or living in communities characterized by trust and social ties may mitigate sleep disparities among sexual minoritized vs. heterosexual persons; but its relation to sleep health is understudied among sexual minoritized groups. To investigate associations between perceived neighborhood social cohesion and sleep health among adult US men and women who identified as “lesbian or gay, bisexual, or something else,” we used cross-sectional National Health Interview Survey data (2013-2018). MethodsParticipants reported neighborhood social cohesion (categorized as low or medium vs. high) and sleep characteristics. Adjusting for sociodemographic, health, and residential characteristics, we used Poisson regression with robust variance to estimate prevalence ratios (PRs) and 95% confidence intervals for poor sleep. ResultsAmong 4666 sexual minoritized adults, 44% reported low, 32% medium, and 24% high neighborhood social cohesion. Women, minoritized racial/ethnic groups, and young adults disproportionately reported low neighborhood social cohesion. Overall, low vs. high neighborhood social cohesion was associated with a higher prevalence of short sleep (PR=1.27 [95% confidence interval:1.11-1.45]) and all sleep disturbances (e.g., PRinsomnia symptoms=1.36 [1.19-1.55]). PRs were often higher as intersectionality or membership to multiple minoritized groups increased. ConclusionsLower perceived neighborhood social cohesion was associated with poorer sleep. Fostering community cohesiveness may mitigate sleep disparities among sexual minoritized adults.

Enhanced biopolymer composites through micro-integrated lignin and anhydride modified nonwoven bast fiber

The growing need for sustainable materials in various industries has driven research towards eco-friendly biopolymer composites. In this study, lignin microfillers were integrated into PHBV/modified bast fiber matrices, offering a promising solution for sustainable material innovation with improved performance and functionality. Nonwoven bast fiber mats were initially treated with propionic, succinic, and maleic anhydrides, evaluated through weight gain analysis, chemical characterization, thermal stability, and wettability assessments. These modified bast fibers were then reinforced with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biopolymer at 30 % loading using specialized molding techniques. The resulting biocomposites were subjected to comprehensive characterization, including moisture related properties, mechanical strength, thermal behavior, and fracturographical properties. In a final stage, lignin microparticles (LMPs) as biofillers were integrated at 1 %, 3 %, 5 %, and 7 % concentrations to enhance biocomposite properties. Experimental findings highlighted succinylated bast fibers as offering the greatest improvements in mechanical strength, thermal stability, and morphological integrity among the modified fibers. At an optimal 5 % lignin microfiller content, the biocomposites exhibited superior wettability and improved stiffness. However, excessive lignin loading led to particle agglomeration, diminishing overall performance. Fracturographical analysis provided insights into the fracture behavior of the biocomposites, highlighting the cohesive and interfacial characteristics of the materials under stress conditions. This research highlights the efficacy of sequential modification strategies in developing high-performance sustainable materials tailored for diverse industrial applications.

Атеизм в цифровую эпоху

The article examines the transformation of atheism as a social and worldview phenomenon in the era of digitalization. Atheistic forums and collective blogs represent a rich field for the study of non-belief; however, they have so far received only sporadic attention from religious scholars and philosophers. The article also presents the phenomenon of “new atheism”. Rather than a system of logical argumentation and classical rational critique of typical theistic arguments, this new atheism comprises a complex of rhetorical techniques aimed at a mass audience, often characterized by irrationality and focused on eliciting specific emotions towards believers rather than fostering an informed understanding of the subject of controversy. Atheism took root in the postmodern situation from its ends of metanarratives, the primacy of feelings over reason, pluralism of opinions and other characteristic features. Moreover, the Internet turned out to be an excellent platform for disseminating the ideas of “new atheism”, promoted by opinion leaders and bloggers, which is a characteristic form of propaganda for Internet media. Nevertheless, the scale of modern non-belief does not approach that of religious movements, nor does it reach the level of cohesion and political passion characteristic of the militant atheism of the 20th century.

Improving The Geotechnical Properties of Cohesive Soils Using Portland Cement and Some Composite Polymers in A Selected Location in The City of Tanumah / Basrah Governorate – Southern Iraq

Background: The purpose of this research is to ascertain how adding Portland cement and composite polymers, as well as the ideal ratios between them, will affect cohesive soils' geotechnical characteristics. Materials and Methods: A composite polymer was created by combining three polymers—isocyanide, unsaturated polyester, polyvinyl acetate, and thinner—as well as a solvent. Portland cement was added to the soil at a rate of 5% of the sample weight. Different percentages of the weight of the cement supplied to the sample—5, 10, 15, 20, and 25%—were utilized as the composite polymer. Several geotechnical tests were carried out, including compaction, unconfined compressive strength, California bearing ratio, absorption, and Atterberg's limits, to ascertain the ideal amount of polymer for the aim of improvement. Results: The findings show that adding cement at a rate of 5% by weight of the sample and a polymeric mixture at a rate of 15% by weight of cement can improve the cohesive soil's engineering properties. It was found that the maximum dry density, unconfined compressive strength, and California bearing ratio had increased while the values of the optimal moisture content, absorption rate, liquid limit values, and plasticity index had decreased. Conclusion: The composite polymer used in soil improvement not only improves the geotechnical properties and resistance of the soil, but it also efficiently enhances and activates the effectiveness of cement. When 15% of the sample's weight of cement was composed of composite polymers, the soil's engineering attributes increased the most.

Spatial evolution and influencing factors of water-town settlements in Southern China: evidence from 942 villages in Zhongshan City

ABSTRACT Zhongshan, a city characterized by its profound historical heritage and distinctive rural civilization, has been consistently influenced by traditional agricultural practices throughout its history. This research conducts an in-depth exploration of Zhongshan’s unique rural spaces, systematically examining the evolutionary trends and determinants of Zhongshan’s water-town settlements across different historical epochs through the application of multidimensional spatial analysis techniques. The results indicate that these settlements exhibited cohesive spatial distribution characteristics across five historical periods. Notably, there was a significant clustering effect during the Ming and Qing dynasties, while Before the Qing dynasty, the spatial distribution of the settlements presented a pattern with multiple core areas coexisting. After the Qing dynasty, the spatial layout of these principal core areas stabilized and gradually diffused to surrounding areas, forming a balanced and continuous distribution pattern. Throughout the study period, the spatial pattern of the water-town settlements exhibited characteristics of five primary core areas and several secondary core areas. Concurrently, the centroid of the water-town settlements consistently shifted southeastward. When examining the intensity of influence on spatial evolution, the study found that socio-economic (q = 0.345) and accessibility factors (q = 0.356) exert a greater impact on the spatial distribution of rural settlements than do natural environmental factors (q = 0.136). However, the interaction between natural environmental factors and socio-economic and accessibility factors provides greater explanatory power than the interactions within natural factors alone. This suggests that in a specific socio-economic context, the impact of the natural environment on water-town settlements is enhanced. Furthermore, multivariate linear regression analysis demonstrates that the rural population, regional economic status, proximity to urban centers, and the distribution of water bodies positively influence the spatial evolution of water-town settlements.

A nonlinear dynamic constitutive model of cohesive soil-captured cyclic strain softening characteristics

The dynamic constitutive relationship of soil is essential for seismic dynamic calculations in geotechnical seismic engineering. Numerous experiments have demonstrated that cohesive soil exhibits cyclic strain softening characteristics under dynamic loading (equal-amplitude loading and unequal-amplitude loading) conditions. However, the Masing criteria (Masing's 2-fold method) cannot describe the cyclic strain softening behaviour of soil for equal-amplitude loading and often fail to estimate the damping ratio accurately (underestimation of the damping ratio at low strain; overestimation of the damping ratio at high strain). Furthermore, the Masing criteria are not applicable for nonequal-amplitude loading. To solve these problems, the research in this paper is based on the Davidenkov skeleton curve, and Masing's 2-fold method is utilized to establish a hysteretic curve. The cyclic strain softening coefficient and damping ratio adjusting coefficient were proposed for equal-amplitude loading to accurately capture the cyclic strain softening properties of cohesive soil. For nonequal-amplitude loading, Masing's n-fold method is employed to establish stress‒strain hysteresis curves, and using the customized constitutive interface reserved by FLAC3D, the development of this constitutive model is achieved on the Visual Studio (VS)2015 platform. The calculation accuracy of the model is verified by comparison with the theoretical values and experimental data, and the rationality of the constitutive model is verified by cyclic direct simple shear tests and cyclic torsional shear tests of soil subjected to equal-amplitude loading and centrifuge model tests of ground bearing unequal-amplitude loading, which provides effective help for the study of earthquake disasters in cohesive soil sites.

Microstructure and mechanical properties of Co31.5Cr7Fe30Ni31.5 high-entropy alloy powder produced by plasma rotating electrode process and its applications in additive manufacturing

Microstructure and mechanical properties of feedstock powders critically determine the quality of additive manufacturing (AM). The present study employs a plasma rotating electrode process (PREP) to produce non-equiatomic Co31.5Cr7Fe30Ni31.5 high-entropy alloy (HEA) powders and examines variations of their microstructure and mechanical properties with powder particle size in the range of 20–106 μm. It finds that the powders possess smooth surfaces, good sphericity, and equiaxed polycrystal grains under PREP electrode rod arc speed of 32000 r/min and main arc current of 760 A. A stable FCC structure is maintained regardless of the powder particle size. Moreover, the nano-hardness of the powders generally decreases with the increase of powder particle size except for that of 50–75 μm, which is positively correlated with the change of the grain size. The finest grain size is present for powders with particle sizes of 50–75 μm, which possess the highest average nano-hardness and reduced elastic modulus. Bulk alloys fabricated by cold spray (CS) and laser cladding (LC) AM maintain the FCC structure. The CSAM bulk alloy shows early brittle fracture due to the presence of pores and prior particle boundaries resulting from insufficient plastic deformation of the powder particles. The LCAM bulk alloy presents good tensile properties with the ultimate tensile strength (UTS) and elongation to failure being 481.2 MPa and 35.9%, respectively, which can be attributed to the good cohesion and grain characteristics. The present study shall provide the field of AM with useful information in the applications of non-equiatomic PREP HEA powders.

Investigation of the cohesive behavior of water-intervened rejuvenated SBS-modified bitumen

When water interacts with bitumen, the diffusion and cohesion characteristics between the components of bitumen are negatively impacted. Molecular dynamics simulations were employed to construct various bitumen models, including bitumen–bitumen (without water), water-containing single bitumen, water-containing bitumen–bitumen, and bitumen–water–bitumen models. The primary research objectives were as follows: comparing the changes in the densities of bitumen models with and without water, analyzing the interlayer cohesive energies of bitumen models interacting with water, evaluating the hydrogen bonds in water-containing bitumen models, and characterizing the diffusion behaviors of bitumen components. The results indicated that when water interacted with the bitumen, it filled internal voids, leading to an overall increase in volume and reduction in density. The interaction energies between the rejuvenated bitumen models and water molecules decreased as the numbers of polar sites exposed to SBS molecules decreased. The numbers of hydrogen bonds between water molecules and rejuvenated bitumen models were similar to those in aged bitumen models. As the number of fractured SBS molecular chains gradually increased, the interlayer cohesive energy in the Methylene-bis(4-cyclohexylisocyanate) (HMDI)-rejuvenated bitumen model gradually increased. Water molecules significantly influenced the interactions at the rejuvenated bitumen–rejuvenated bitumen interface, weakening the cohesion characteristics between bitumen molecules. Water interactions significantly reduced the interlayer cohesive energy of the bitumen–water–bitumen model. Conversely, the recovery process improved the interlayer cohesion characteristics of the bitumen. The diffusion characteristics of the components of bitumen SARA were significantly greater under wet conditions than under dry conditions.

Effects of the demineralisation degree on physicochemical, functional, microstructural and powder flow properties of whey powder

This study aimed to investigate the effects of the demineralisation process on powder flow, physicochemical, functional, and microstructural properties of whey powders (WP). WP samples were produced from 50, 70 and 90% demineralised sweet whey concentrates. Although the salt, ash, and lactic acid content of the powders decreased with increasing demineralisation, pH increased. D [3,2] (surface area mean diameter) value of WP samples ranged from 28.2 to 60.9 μm, in which demineralisation increased the particle size. The colour values showed increased darkness and yellowness, attributed to the higher demineralisation process. Demineralisation improved solubility and foaming characteristics, whereas it decreased the wettability and dispersibility of samples. The caking and cohesion characteristics of WP were significantly decreased by demineralisation. Demineralisation significantly improved the powder flow characteristics of samples. The cohesion index decreased depending on the demineralisation degree increased. Also, demineralisation decreased the cake strength and compaction coefficient of samples. Mineral content decreased with increasing demineralisation, with some minerals showing more sensitivity to demineralisation than others. Scanning Electron Microscope images showed reduced caking and clustering in samples with higher degrees of demineralisation. The results highlighted the importance of demineralisation as an effective parameter to control the properties of WP. In conclusion, this study demonstrated that the degree of demineralisation had a substantial impact on the physical and functional properties of WP.

MolLoG: A Molecular Level Interpretability Model Bridging Local to Global for Predicting Drug Target Interactions.

Developing new pharmaceuticals is a costly and time-consuming endeavor fraught with significant safety risks. A critical aspect of drug research and disease therapy is discerning the existence of interactions between drugs and proteins. The evolution of deep learning (DL) in computer science has been remarkably aided in this regard in recent years. Yet, two challenges remain: (i) balancing the extraction of profound, local cohesive characteristics while warding off gradient disappearance and (ii) globally representing and understanding the interactions between the drug and target local attributes, which is vital for delivering molecular level insights indispensable to drug development. In response to these challenges, we propose a DL network structure, MolLoG, primarily comprising two modules: local feature encoders (LFE) and global interactive learning (GIL). Within the LFE module, graph convolution networks and leap blocks capture the local features of drug and protein molecules, respectively. The GIL module enables the efficient amalgamation of feature information, facilitating the global learning of feature structural semantics and procuring multihead attention weights for abstract features stemming from two modalities, providing biologically pertinent explanations for black-box results. Finally, predictive outcomes are achieved by decoding the unified representation via a multilayer perceptron. Our experimental analysis reveals that MolLoG outperforms several cutting-edge baselines across four data sets, delivering superior overall performance and providing satisfactory results when elucidating various facets of drug-target interaction predictions.

Modulation of Physical and Thermal Properties in Wild Banana (Musa balbisiana Colla) Seed Powder by Moisture Variations.

Engineering and flow properties of banana seed powder as a function of moisture content are important for processing, handling, packaging, and transport processes. The bulk density, tapped density, and porosity increased from 377.37 to 427.36 kg m-3, 622.08 to 746.33 kg m-3, and 38.99-43.74%, respectively, within the increasing moisture content range. The Hausner ratio (Hr) and Carr's compressibility index (CI) significantly (p < 0.05) increased with an increase in moisture content (6.16-19.56% db) of banana seed powder, whereas HR fell in the range of 1.4-2.0, indicating cohesive characteristics of banana seed powder. The angle of repose, angle of spatula, and angle of fall exhibited a linear increase, ranging from 40.6° to 49°, 33.4° to 39.4°, and 35.6° to 42.6°, respectively, with increasing moisture content. The static coefficient of friction was found to be highest for aluminium and glass surfaces and least for stainless steel. The water activity and swelling power of banana seed powder showed a significant increase, while the solubility and oil absorption capacity exhibited a significant decrease within the range of increasing moisture content. The thermal characteristics of wild banana seed powder, such as thermal conductivity (0.16 to 0.20 Wm-1 K-1) and volumetric specific heat (0.58 to 0.99 MJm-3 K-1), demonstrated an increasing trend as the moisture content increased. However, the thermal diffusivity showed a decrease from 0.31 to 0.19 (×10-6 m2s-1) with the increase in moisture content.

ANALYSIS OF LABORATORY STUDIES OF HYDROPHOBIC EMULSIONS TO ENSURE WATER INSULATION WORK IN OIL FIELDS

This article is devoted to the research and implementation of methods for ensuring water insulation works (WIW) in the oil sector using hydrophobic emulsions. In the context of modern requirements for environmental safety and efficiency of production processes in the oil industry, where water can become a source of problems, the introduction of innovative materials and technologies plays an important role. Conducting laboratory studies of hydrophobic emulsions for WIW in the oil sector is a multiprocess approach, starting from the initial assessment of the chemical component and ending with thorough testing for compliance with the requirements of specific operating conditions. The analysis evaluates the physico-chemical properties of the emulsion, such as density, viscosity, pH level, degree of dispersion, as well as its adhesive and cohesive characteristics. Special attention is paid to the study of the surface properties of hydrophobic emulsions, since their ability to form stable water-repellent coatings directly affects the effectiveness of protection against water exposure. To do this, tests are carried out on wettability, contact angle, adhesion to various types of surfaces, which allows us to determine the optimal conditions for the use of emulsions in specific situations. The article describes the principles of action of hydrophobic emulsions in the context of waterproofing works, emphasizing their ability to create a protective barrier, preventing moisture penetration into oil facilities. The paper presents the results of laboratory studies demonstrating the effectiveness of the use of hydrophobic emulsions in various operating conditions. The article discusses the technical aspects of the use of hydrophobic emulsions in the WIW process, analyzes their resistance to various environmental factors, and also considers the prospects for the development of this technology in the oil industry. The results obtained can be useful for specialists dealing with water insulation in oil companies, as well as for the scientific and engineering community interested in the development of innovative technologies in the oil sector. The purpose of this article is to analyze laboratory research and provide recommendations on the use of polymer composition.

Individual characteristics on multicultural team performance: does the role played by leaders and team members matter?

The main purpose of this study was to analyze the impact of individual characteristics of cultural sensitivity, adaptability, cohesion, and cultural diversity on the multicultural team performance. Also, we analyzed the moderating effect of being a team member or a team leader on the relationships mentioned above. To test out hipotheses, data were collected from 415 members of multicultural teams specifically, from 304 team members and 111 leaders. The findings provided evidence to support a positive relationship between cultural sensitivity, adaptability, cohesion, and team performance. Cultural diversity did not show a significant impact on team performance. The study also showed that the leaders and members had different perceptions about the factors that influence team performance. For instance, team members consider that cohesion influences team performance, while leaders consider adaptability as the key factor to achieve performance. Main implications from findings are discussed.

CURRENT STATE OF METHODS FOR DETERMINING THE ADHESIVE AND COHESIVE PROPERTIES OF ROAD BITUMEN

The sphere of transport infrastructure is developing rapidly, which underlines the importance of stable properties of bitumen in the construction of road surfaces. A necessary condition for improving the quality of the bitumen binder is its high adhesionto the surface of the mineral filler. The adhesion of bitumen with mineral filler is an important indicator that characterizes the quality of the asphalt concrete mixture, the performance characteristics of the asphalt concrete coating and its resistance to damage. An adequate assessment of these characteristics becomes a key factor in ensuring the durability and reliability of road surfaces. The article analyzes the current state of methods for determining the adhesive and cohesive characteristics of bitumen and mineral filler. The aimof the work is a thorough analysis of various methods used to evaluate the adhesive and cohesive properties of bitumen, with subsequent identification of their advantages and disadvantages. An overview of both traditional and modern approaches used to determine these characteristics is given to better understand the structure and behavior of bituminous materials. Conclusion. The article emphasizes the need for further research and development in the field of methods for determining the adhesive and cohesive properties of bitumen, considering modern requirements for road infrastructure. It is necessary to develop scientific and practical approaches to improving existing regulatory documents considering the characteristics of bituminous materials.It can be concluded that it is necessary to develop new accurate reproducible methods using computer technologies that automate data collection and processing and reduce the likelihood of errors.

Influence of Matrix and Cohesive Material Law Characteristics on the Tensile and Bond Behavior of FRCM Systems

Influence of Matrix and Cohesive Material Law Characteristics on the Tensile and Bond Behavior of FRCM Systems

Maltodextrin as a Drying Adjuvant in the Lyophilization of Tropical Red Fruit Blend.

Guava, pitanga and acerola are known for their vitamin content and high levels of bioactive compounds. Thus, the preparation of combinations of these fruits comprises a blend with high nutraceutical potential, yielding a strong and attractive pigmentation material. In this study, the influence of different proportions of maltodextrin on the lyophilization of a blend of guava, acerola and pitanga was evaluated considering not only the physicochemical, physical and colorimetric parameters but also the bioactive compounds in the obtained powders. The blend was formulated from the mixture and homogenization of the three pulps in a ratio of 1:1:1 (m/m), then maltodextrin was added to the blend, resulting in four formulations: blend without adjuvant (BL0), and the others containing 10% (BL10), 20% (BL20) and 30% (BL30) maltodextrin. The formulations were lyophilized and disintegrated to obtain powders. The powders were characterized in terms of water content, water activity, pH, total titratable acidity, ash, total and reducing sugars, ascorbic acid, total phenolic content, flavonoids, anthocyanins, carotenoids, lycopene, color parameters, Hausner factor, Carr index, angle of repose, solubility, wettability and porosity. All evaluated powders showed high levels of bioactive compounds and the increase in maltodextrin concentration promoted positive effects, such as reductions in water content, water activity and porosity and improved flow, cohesiveness and solubility characteristics.

The correlation between the pre-consolidation and Instantaneous Yield Locus (IYL) of bulk solids

The storage and transportation of bulk materials has seen a continuous increase in demand with the evolution of renewable energy systems and modern society. The extraction of minerals such as iron ore, copper, nickel, bauxite, and lithium is leading to the exploitation of previously abandoned mine sites as well as ore bodies that may have been disregarded. This demand necessitates more efficient systems to transport these bulk commodities from the mine site to the export terminal or end user. The design of new bulk material handling systems typically requires the measurement of the bulk material strength, commonly determined using a Jenike direct shear tester. Initially, these measurements were used for the design of free-flowing bulk commodities, such as grain in storage silos or granaries. Over more recent decades, Jenike direct shear measurements have been used for the determination of the flow properties of problematic bulk materials which show cohesive characteristics. Specifically, this testing is used to define the flow function of a bulk material, the relationship between the material strength and major principle stress, which is subsequently used in the design of material handling systems.This paper provides a mathematical relationship between the pre-consolidation and the Instantaneous Yield Locus (IYL) of a bulk material sample under Jenike direct shear testing conditions. When the voidage between the particles is considered, this relationship becomes critical in defining the stress states of a bulk material sample. By understanding these stress conditions, further insight into the tensile forces which lead to problematic material behaviours can also be gained. This becomes increasingly important when low consolidation applications, such as transfer chutes, are considered as this leads to blockages and therefore downtime and lost revenue within a mining operation results. To further gain an understanding of the tensile forces acting within a bulk material sample, inter-particle adhesion tests are compared with predicted values which are determined using the outlined mathematical relationship.

Investigation of dynamic response of drilling parameters and deformation characteristics of coal around borehole during multi-stage reaming in tectonic coal

Tectonic coal refers to the coal with varying degrees of brittle fracture or ductile deformation under the action of one or multi-period tectonic stresses, showing the characteristics of low mechanical strength, weak cohesion and large deformation. Therefore, drilling in tectonic coal is easy to cause the aperture shrinkage or closure due to the poor anti-deformation capability. Enlarging the initial borehole can effectively increase the borehole diameter and reduce the risk of pipe jamming and burying without changing the borehole structure. In order to investigate the dynamic evolution characteristics of drilling parameters in the process of drilling and reaming in tectonic coal, a self-designed drilling experimental system that can monitor drilling parameters in real time was used in this study. Additionally, the acoustic emission (AE) response and borehole wall strain were observed to study the coal-breaking and the deformation characteristics of coal around borehole. The results demonstrate that the drilling rate and drilling torque increase sequentially in the initial drilling, primary reaming and secondary reaming stages. The magnitude of drilling rate is affected by both drilling thrust and rotational speed, whereas drilling torque is mainly affected by drilling thrust. The intensity of AE phenomena increases gradually at different stages of the borehole formation, which means that the drilling efficiency is improved and more strain energy is accumulated in the coal around the borehole during reaming. The borehole wall strain effectively reflects the convergence deformation of borehole wall, that is, the larger the borehole diameter, the greater the deformation of the borehole wall. The deformation of borehole is mainly affected by the redistribution of stress in the coal body, rather than the drilling parameters.

A Strain Hardening and Softening Constitutive Model for Hard Brittle Rocks

To study the strain hardening and softening mechanism for hard brittle rocks, a strain hardening and softening constitutive model for hard brittle rocks is developed. First, the normalised hardening and softening factors are defined, which characterise the yield state of rock at the stages of pre-peak hardening and post-peak softening, respectively. Then, a unified strength parameter evolution model is established that can describe the nonlinear characteristics of cohesion and the internal friction angle under different confining pressures. Based on the Mohr–Coulomb criterion, a strain hardening and softening constitutive model is proposed. Finally, the proposed model was implemented in FLAC3D, and triaxial compression numerical tests of granite and diabase were conducted. The results show that the constitutive model can characterise the nonlinear mechanical behaviour of the pre-peak hardening stage and post-peak softening stage of hard brittle rock. The model was also able to satisfactorily capture the transition from brittle failure to plastic failure for hard brittle rock under high confining pressures.

Synthesis of Novel CuO–Gelatin Nanofluids Using Ultrasonic Technique

AbstractNanofluid molecular properties, such as acoustical properties, vary widely in system parameters and are influenced by liquid cohesive characteristics. Gelatin is a natural polymer made from the partial hydrolysis of collagen, which allows the triple helix to unfold and split, resulting in a polydisperse mixture of proteins in solution. The use of ultrasonic technology to create nanoparticles from biopolymer base fluids is a novel method of nanofluid synthesis. The focus of this research is to measure the ultrasonic velocity and density of synthesized nanoparticles using gelatin as the base fluid at various weight percentages. The study have synthesized the Copper oxide (CuO) nanofluid by transforming an unstable Cu(OH)2 to CuO as a precursor in aqueous gelatin by ultrasonication process. To characterize the prepared nanoparticles, the XRD and FESEM methods are used. The results of ultrasonic velocity, density, and viscosity measurements are discussed after ultrasonication. Experimental data and a theoretical approach to nanofluids are used to study the stability of nanofluids. The outcomes of ultrasonic spectroscopy and other investigations are very similar.