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Ferroelectric materials are widely used in actuators, exciters, and memory devices due to their excellent electromechanical properties. However, the instinctive brittleness of ferroelectric materials makes them easy to fracture under external load. Since giant strain gradient can be easily generated near the crack tip, the flexoelectric effect is indispensable in the research of fracture properties of ferroelectric materials. With the combination of time-dependent Ginzburg–Landau theory and phase-field model, the electromechanical behavior of PbTiO 3 in the vicinity of the crack tip is determined in this work. The simulation results demonstrate that the domain structure near the crack tip becomes asymmetric with the flexoelectric effect. The polarization switching-induced toughening, which is characterized by the J -integral, depends on the direction of the crack relative to the original polarization orientation. Furthermore, the longitude flexoelectric coefficient f 11 has more significant impact on the fracture toughness than that of the transverse flexoelectric coefficient f 12 and the shear flexoelectric coefficient f 44. The results of the present work suggest that the flexoelectric effect must be considered in the reliable design of ferroelectric devices. [ABSTRACT FROM AUTHOR]

The aim of this investigation is to assess the impact of using nano‐silica (Na) at varying weight percentages of 0%, 1.5%, 3%, 4.5%, and 6% as partial cement substitute on fracture parameters of recycled aggregate concrete (RAC). A servo‐controlled testing system was employed to carry out three‐point flexure tests on 90 notched beams. Boundary effect method was used in order to interpret the fracture features. The results illustrate that adding Na increases the size‐independent fracture energy, fracture toughness and initial fracture energy of RAC by 29%, 32%, and 24% compared to that without Na, respectively. The maximum values of these parameters occur at 4.5% Na. The reference crack length (α∞*$$ {\alpha}_{\infty}^{\ast } $$) decreases from 6% to 22% by adding 1.5% to 6% Na. This shows that the RAC gets more brittle by the addition of Na. Moreover, the RAC behavior moves towards linear elastic fracture mechanics criteria by adding Na. Finally, according to the mechanical properties and test variables, multivariable models were suggested for prediction of the fracture parameters of the RAC containing Na. The models predictions were compared with experimental findings of the previous research. [ABSTRACT FROM AUTHOR]

The document discusses the affinity of silica authigenesis to organic-rich host rocks, the dissolution of silica by organic matter in Xuanwei Formation coal, and the identification of silica polymorphs. It also addresses the sources of silica for silicification, distinguishing between intraformational and extraformational sources. The text highlights the importance of considering abiotic hydrothermal silica sources in addition to plant-derived sources. The author emphasizes the need for further research and analysis to fully understand the complex processes of silica formation in coal seams. [Extracted from the article]

Introduction: Young's modulus and shear modulus are essential mechanical parameters for evaluating subsurface rocks, playing a pivotal role in the exploration and development of unconventional resources. Young's modulus indicates the brittleness of the reservoir, while shear modulus determines the ease of fracturing rock layers. Methods: Traditional methods estimate these moduli through indirect calculations and approximate expressions, which are prone to cumulative errors and rely on multiple assumptions, reducing inversion accuracy. This paper presents a direct inversion method for acquiring of Young's modulus and shear modulus using the exact Zoeppritz equations, integrated within a Bayesian framework for pre-stack inversion. The quantum particle swarm optimization (QPSO) algorithm is introduced to achieve a nonlinear solution to the objective function. Results: Tests on synthetic and actual field data demonstrate the feasibility and effectiveness of the proposed method, yielding more accurate inversion results compared to traditional methods. Discussion: These findings provide valuable insights for predicting reservoir brittleness and characterizing reservoirs in unconventional shale gas exploration and development. [ABSTRACT FROM AUTHOR]

Due to the polycrystalline cubic boron nitride tool has the characteristics of high hardness, brittleness, etc., it is easy to break the tool or produce defects in the laser cutting process, which affects the cutting performance of the tool. Traditional defect detection methods can no longer meet the needs of modern manufacturing. Aiming at the problems of low accuracy and poor real-time detection of surface defects on laser-cutting polycrystalline cubic boron nitride tools, this study proposes the surface defect detection model of laser cutting polycrystalline cubic boron nitride tool based on asymptotic fusion strategy, which fills the gap in the field. In the backbone network, the C3SE module is constructed by modeling the correlation between feature channels to improve the model's focus on key features in order to enhance the feature extraction and processing capability of the backbone network; In the neck network, adaptive spatial fusion operation and direct interaction of non-adjacent layers are utilized for multi-scale information fusion, and the asymptotic feature pyramid network for object detection (AFPN) is used instead of the FPN structure to improve the detection performance; In the head network, a soft suppression mechanism is introduced to reduce the overlapping frame score using a decay function, thus improving the detection accuracy. The experimental results based on the self-constructed laser-cutting polycrystalline cubic boron nitride tool surface defects dataset show that the average accuracy of the AFFS-YOLO model is improved by 5.6% compared with that of the YOLOv5 model, reaching 86.1%, and the detection effect is better than that of the original network and other classical target detection networks. [ABSTRACT FROM AUTHOR]

Organic photodetectors (OPDs) hold immense promise for stretchable and wearable applications, but their photoactive films demonstrate brittleness, stiffness, and mechanical instability, posing challenges for future applications. Herein, the nanoconfinement effect is reported to substantially improve the stretchability and mechanical stability while reducing the stiffness of photoactive films, simultaneously maintaining the high light detection performance. The microstructure, mechanical properties, and photoelectric performance of the quaternary blend films with varying elastomer contents are thoroughly characterized. Additionally, the elastic modulus of quaternary blends can be accurately predicted by the Coran–Patel model. Cyclic tensile tests demonstrate enhanced mechanical stability, resulting in a specific detectivity of the quaternary blend with the nanoconfinement effect being 19 times higher than that of the ternary blend after 200 cycles. Overall, this study provides novel insights into constructing stretchable blend films for wearable electronics. [ABSTRACT FROM AUTHOR]

First-principles study is used to comparatively study the hydrogen embrittlement resistance, elastic properties, and electronic structures of VWH and VMoH phases with various W and Mo concentration. Calculations reveal that the VMo phases have lower hydrogen solubility compared to VW phases, leading to higher hydrogen embrittlement resistance in VMo. In addition, the concentrations of W and Mo above 0.1875 would enhance the hydrogen embrittlement resistance of V membrane. Conversely, the W or Mo concentrations below 0.1875 would reduce the hydrogen embrittlement resistance. It is also demonstrated that adding W and Mo at concentrations below 0.25 would reduce the solid-solution strengthening of VH phase, thereby reducing its brittleness. This study will enhance comprehension of the underlying physics of VWH and VMoH phases and align with existing experimental literature. • Adding Mo is more effective than adding W in improving the hydrogen embrittlement resistance of V membrane. • The concentrations of W or Mo above 0.1875 would enhance the hydrogen embrittlement resistance of V membrane. • The W or Mo concentrations below 0.1875 would reduce the hydrogen embrittlement resistance. • Adding W and Mo at concentrations below 0.25 would reduce its brittleness. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride) (PVC) is a widely employed plastic across diverse industries and is often associated with plasticizers, additives that decrease the inherent rigidity and brittleness of the material. Conventional phthalate‐based plasticizers raise substantial toxicity concerns, encouraging the exploration of bio‐based alternatives. One such alternative is the inedible oil, cashew nutshell liquid (CNSL), mainly composed of cardanol and cardol. Recent efforts have focused on developing a cardanol‐based PVC plasticizers but the isolation of cardanol involves time‐consuming, energy‐intensive, and costly steps, limiting its market competitiveness. This study aims to assess for the first time, the efficiency of cardol esters, synthesized using acetic acid and different fatty acids (octanoic acid and myristic acid), in order to evaluate the influence of the alkyl chain on plasticizer properties. The chemical structures of these plasticizers were fully characterized by 1H NMR spectroscopy, and the mechanical properties and thermal behavior of PVC films plasticized with these additives were investigated. Finally, the endocrine activity was evaluated for cardol and cardanol acetates. [ABSTRACT FROM AUTHOR]

This study investigated the evolution of mass-exchange, physicochemical, mechanical, thermal, and structural properties of meat analog (MA)-based batter-coated parfried food. Wheat and rice flour–based batter systems were used to coat the MA. Parfried (at 180 °C for 60 s) MA were frozen at − 18 °C, − 76 °C, and liquid N2 and stored at − 18 °C for up to 6 months. Parfried MA were finish-fried at 180 °C for 180 s and their attributes were studied. Results reveal that batter formulation and freezing considerably impact the moisture-fat profile as well as textural attributes (hardness, brittleness, crispiness) of finish-fry–coated MA. The color of finish-fry–coated MA is batter formulation–dependent and different than parfried MA. Freezing at − 76 °C slowed quality deterioration of parfried MA in comparison to freezing at − 18 °C. Compared to low-moisture–containing parfried MA, high-moisture–containing coated parfried MA are greatly affected by the freezing process and frozen storage. Storage loss (SL, %) of coated parfried MA increased with the duration of frozen storage, and SL is greatly impacted by batter formulation. Frozen storage duration of parfry-coated MA is negatively correlated with the moisture content of finish-fried MA. Storage duration is positively correlated with fat content and hardness of finish-fried MA. Batter formulation impacted glass-transition temperature (Tg) of parfried MA, that consequently affected their frozen storage quality and finish-frying behavior. Scanning electron microscopy provided mechanistic insights in understanding the impacts of batter formulation and freezing rates on microstructural attributes and consequentially quality evolution of MA-based coated product. [ABSTRACT FROM AUTHOR]

Tight sandstone reservoirs, despite their low porosity and permeability, present considerable exploration potential as unconventional hydrocarbon resources. Natural fractures play a crucial role in hydrocarbon migration, accumulation, and present engineering challenges such as late-stage reformation in these reservoirs. This study examines fractures in the seventh member of the Triassic Yanchang Formation's tight sandstone within the Ordos Basin using a range of methods, including field outcrops, core samples, imaging and conventional logging, thin sections, and scanning electron microscopy. The study clarifies the characteristics of fracture development and evaluates the relationship between dynamic and static rock mechanics parameters, including the calculation of the brittleness index. Primary factors influencing fracture development were quantitatively assessed through a combination of outcrop, core, and mechanical test data. Findings reveal that high-angle structural fractures are predominant, with some bedding and diagenetic fractures also present. Acoustic, spontaneous potential, and caliper logging, in conjunction with imaging data, enabled the development of a comprehensive probabilistic index for fracture identification, which produced favorable results. The analysis identifies four key factors influencing fracture development: stratum thickness, brittleness index, lithology, and rock mechanical stratigraphy. Among these factors, stratum thickness is negatively correlated with fracture development. Conversely, the brittleness index positively correlates with fracture development and significantly influences fracture length, aperture, and linear density. Fractures are most prevalent in siltstone and fine sandstone, with minimal development in mudstone. Different rock mechanics layer types also impact fracture development. These insights into fracture characteristics and controlling factors are anticipated to enhance exploration efforts and contribute to the study of similar unconventional reservoirs. [ABSTRACT FROM AUTHOR]

Hybrid interaction/co‐working mechanisms of waste cellulose (WC) fibers and expanded vermiculite (V) in polypropylene (PP) resulted in stronger, stiffer, and thermally durable composites are presented. Fibrous WC and particulate V inclusions were mixed with the PP matrix via high shear thermokinetic mixer under 4000 rpm. Thermal and mechanical characterization efforts assisted with fractographic investigations are performed on five sample sets such as (i) two‐phase WC fibrous PP composites and (ii) three‐phase WC–V hybrid composites. Results suggested that as the main reinforcement agent WC is able to increase the axial stiffness of PP (1.7 GPa) up to 4 GPa (30WC) as the weight fraction increases with a reduction in ductility. However, a strength threshold due to WC cluster entanglement, which leaves partially non‐wet clusters of WC and limited crystallization volume for PP at high WC weight fractions, is noted. In situ formed V platelets placed between WC fibers are proven to provide PP crystallization loci to further increase the axial stiffness (4.1 GPa) and matrix brittleness. When used with 10WC, they significantly increased the ability of PP matrix r to resist the failure events associated with the presence of randomly aligned WC fibers. Such ability is further highlighted in the 20WC10V case where the inherent problem of WC entanglement increased the contribution of polymer shear failure to the overall tensile response of manufactured composites. A significant increase in tensile strength (55%) for this case was recorded which makes the proposed hybridization effort more advantageous to conventional short fiber reinforcing strategies. Highlights: Stiffer and stronger PP‐based hybrid composites with waste cellulose and vermiculite.Tensile failure/toughening mechanisms in hybrid PP compositesSustainable approach for reinforcement selection. [ABSTRACT FROM AUTHOR]

Sapphire crystal with excellent properties is widely used as substrate materials for optoelectronics and microelectronics industries. Subsurface crack damage (SSD) will occur in the diamond wire saw slicing process of the sapphire wafer, which is related to the quality of the as-sawn wafer and the cost of subsequent processing. Therefore, rapid and effective detection of SSD is required in production. However, current detection methods are time-consuming and labor-intensive, thus requiring a fast, effective, and low-carbon evaluation method. In this paper, based on the current diamond wire saw slicing process parameters range of sapphire crystal in actual production, sawing experiments were carried out to study the surface and subsurface crack damage morphology characteristics, evolution law of surface roughness (Rz), and SSD. Furthermore, the mapping relationship between Rz and SSD was established by the numerical fitting method. The results show that, in the range of processing parameters for practical industrial applications, the surface of the as-sawn wafer was mainly formed by material brittleness removal, the subsurface presented a small number of micro-cracks and brittle fracture damage, and the median crack propagation direction was shifted. Within the range of process parameters used in this study, the maximum SSD value of the sapphire wafer is 20.07 µm, the minimum value is 11.67 µm, and the corresponding Rz values are 11.13 µm and 8.12 µm, respectively. Both SSD and Rz decreased with the increase in saw wire speed and the decrease in specimen feed speed. There is a nonlinear relationship of monotone increase between the two, which is SSD = 0.15Rz3 − 4.87Rz2 + 55.49Rz − 195.23. The research results can be used to evaluate SSD quickly and effectively by measuring as-sawn sapphire wafer Rz that can provide an experimental reference for wire-sliced SSD evaluation, wafer quality improvement, and processing parameter optimization. [ABSTRACT FROM AUTHOR]

Inorganic semiconductor materials are crucial for modern technologies, but their brittleness and limited processability hinder the development of flexible, wearable, and miniaturized electronics. The recent discovery of room-temperature plasticity in some inorganic semiconductors offers a promising solution, but the deformation mechanisms remain controversial. Here, we investigate the deformation of indium selenide, a two-dimensional van der Waals semiconductor with substantial plasticity. By developing a machine-learned deep potential, we perform atomistic simulations that capture the deformation features of hexagonal indium selenide upon out-of-plane compression. Unexpectedly, we find that indium selenide plastifies through a martensitic transformation; that is, the layered hexagonal structure is converted to a tetragonal lattice with specific orientation relationship. This observation is corroborated by high-resolution experimental observations and theory. It suggests a change of paradigm, where the design of new plastically deformable inorganic semiconductors can focus on compositions and structures that facilitate phase transformations, going beyond the conventional dislocation slip. [ABSTRACT FROM AUTHOR]

The challenging machinability of silicon carbide (SiC) ceramic, due to its hardness and brittleness, has traditionally constrained its machined quality and the creation of functional surfaces. Compared to direct laser machining (DLM), waterjet-assisted laser micromachining (WJALM) is an alternative technique for SiC ceramic that is capable of reducing thermal-induced damages. In this paper, high-aspect-ratio (HAR) microchannels are fabricated on silicon carbide ceramic by WJALM, and its effectiveness is verified through comparative experiments with DLM. The effects of the parametric combination of waterjet and laser parameters on machining responses of geometric structural features and sidewall surface quality are investigated by controlled variable experiments. The results revealed that HAR microchannels with almost no recast layers could be obtained when the SiC workpiece was fabricated by a nanosecond laser under the flowing water medium layer, and higher average laser power of 27 W, lower scanning speed of 600 m/s, and medium waterjet velocity of 12/16 m/s contributed to larger aspect ratio, more ablation area and superior sidewall quality of HAR microchannels. [ABSTRACT FROM AUTHOR]

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The idea of enhancing concrete slabs' ability to resist impact has been discussed in this study and, specifically, the use of soft drink can strips fibers (SDCSF). Concrete structures are classified as brittle material when happen to be exposed to impact loads like the firing of guns. Some of the past research works revealed that subjected to impact loads, the concrete structures disintegrated into several pieces. And because of the brittleness, fibers are incorporated into concrete at various ratios of 0. 5%, 1%, and 1.5% mean weight of cement and various proportions of 3cm, 6cm, and 9 cm to enhance concrete's resistance. Squire slab specimens with the dimension of (500 mm × 500 mm) and thickness of 50 mm. Ten specimens were subjected to high-velocity impact load by gunfire from a weapon M16, bullet diameter 7.62 mm, from a distance of 15 m. The arrangement used was to impact a single point (one bullet) at the centre of each panel. The research found that using such a type of fiber with different percentages and lengths could increase the resistance impact load. Moreover, the results showed that reducing the spalling area, the scabbing area, and reducing the redial crack length. It can be concluded that the spalling area of specimens with 1.5% soft drink can strips and 9 cm length at 28 days decreased by 21.48% compared to the reference sample (R). The scanning area of specimens with 1.5% soft drink can strips and 9cm length at 28 days was decreased by 24.72% compared to the reference sample (R). The redial crack length of specimens with 1.5% soft drink can strips and 9cm length at 28 days was decreased by 29.32% compared to the reference sample (R). [ABSTRACT FROM AUTHOR]

The main objective is to optimize the development of shale gas-rich areas by predicting seismic sweet spot parameters in shale reservoirs. We systematically assessed the fracture development, fracture gas content, and rock brittleness in fractured gas-bearing shale reservoirs. To better characterize gas-bearing shale reservoirs with tilted fractures, we optimized the petrophysical modeling based on the equivalent medium theory. Based on the advantages of shale petrophysical modeling, we not only considered the brittle mineral fraction but also the combined effect of shale porosity, gas saturation, and total organic carbon (TOC) when optimizing the brittleness index. Due to fractures generally functioning as essential channels for fluid storage and movement, fracture density and fracture fluid identification factors are critical geophysical parameters for fractured reservoir prediction. We defined a new fracture gas indication factor (GFI) to detect fracture-effective gas content. A new linear PP-wave reflection coefficient equation for a tilted transversely isotropic (TTI) medium was rederived, realizing the direct prediction of anisotropic fracture parameters and the isotropic elasticity parameters from offset vector tile (OVT)- domain seismic data. Synthetic seismic data experiments demonstrated that the inversion algorithm based on the LP quasinorm sparsity constraint and the split-component inversion strategy exhibits high stability and noise resistance. Finally, we applied our new prediction method to evaluate fractured gasbearing shale reservoirs in the Sichuan Basin of China, demonstrating its effectiveness. [ABSTRACT FROM AUTHOR]

Recently, a new promising type of marine shale gas reservoir, carbonate-rich shale, has been discovered. But the mechanical properties of this type of shale were still unrevealed and the corresponding reservoir stimulation designwas lack of guidance. Using the deep downhole cores of an exploratory carbonate-rich shale gas well, the physical and mechanical parameters and failure mechanism of the whole reservoir section were acquired and evaluated systematically, by performing XRD, tri-axial compression, Brazilian splitting, and fracture toughness tests. A new model was established to evaluate the reservoir brittleness based on fracture morphology and stress-strain curve. Recommended strategy for reservoir stimulation was discussed. Results showed that (1) Carbonate-rich shale possessed high compressive strength and high Young's modulus, which were improved by 10.74% and 3.37% compared to that of siliceous shale. It featured high tensile strength and fracture toughness, with insignificant anisotropy. (2) With the content of carbonate minerals increasing, the shear failure morphology transformed from sparse and wide brittle fractures to diffusely distributed and subtle plastic cracks. (3) The brittleness index order was: siliceous shale, clay-rich shale, carbonate-rich shale, and limestone. (4) The special properties of carbonate-rich shale were rooted in the inherent feature of carbonate minerals (high strength, high elastic modulus, and cleavage structure), resulting in greater challenge in reservoirs stimulation. The above findings would promote the understanding of carbonate-rich shale reservoirs and provide reference for the optimum design of reservoir stimulation. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane (WPU) often suffers from poor water resistance and mechanical properties due to hydrophilic emulsifiers. To address these issues, this study introduces glycidyl carbamate (GC) as a crosslinker to improve WPU performance. Three types of GC were synthesized using aliphatic, cycloaliphatic, and aromatic isocyanates, respectively. The crosslinked network was established through a reaction between the epoxide group of GC and the carboxylic acid and amine groups of WPU. Among these, the WPU film utilizing aromatic isocyanate-based GC exhibited the highest crosslink density, modulus, hardness, and water resistance, due to the rigidity of the aromatic molecular structure. However, the film displayed excessive brittleness, resulting in reduced tensile strength, along with yellowing typically associated with aromatic compounds. The WPU crosslinked with cycloaliphatic GC demonstrated the next best mechanical properties and water resistance, with a 2.7-fold increase in tensile strength, a 1.5-fold increase in hardness, and a 66% reduction in the water swelling ratio compared to neat WPU. This study presents a novel and effective strategy to enhance the water resistance and mechanical properties of WPU films, making them suitable for advanced coating applications. [ABSTRACT FROM AUTHOR]

The brittleness of shales is critical to hydraulic fracturing since rock with high brittle minerals are more likely to fracture and maintain open fractures. Shale rocks have a wide range of constituting components, and different minerals display distinct elastic behavior. The microscale measurements of mechanical properties indicate that pyrite has the highest Young's modulus, followed by quartz and feldspar. Organic matter was commonly recognized as the soft component, and has very low Young's modulus. Alkaline minerals show similar Young's modulus values to quartz and feldspar, and can be grouped into brittle minerals. The relative content, source and structure of brittle minerals can affect rock brittleness from multiple scales. Understanding the relationship between mineral compositions and geomechanical properties is beneficial for fracability estimation in engineering applications for shales. [ABSTRACT FROM AUTHOR]

Rock abrasivity plays an important role in the machine design, construction scheduling, and budgeting of TBM projects. Establishing several faster and simpler estimation equations for the Cerchar Abrasivity Index (CAI) of rocks is, therefore, very important. This study investigated the correlation between the CAI and mechanical properties of rock, rock mass classification parameters, and machine performance. A TBM construction database including 159 tunnel sections is established. Several acceptable and practical estimation equations of CAI are developed using simple and multiple regression analysis (0.66 < R2 < 0.76). In this process, a normalized specific energy is proposed to evaluate the machine performance. The results show that the rock compressive strength and brittleness index are the most dependent parameters to explain CAI, and the estimated rock mass strength also indicates a close correlation. In addition, the contribution of a rock mass classification system and machine performance index for estimating CAI cannot be ignored. Finally, the estimation performance of the developed equations is compared and evaluated, and a new method for selecting an optimal model based on ranking is proposed. Since the input parameters of the proposed equations can be readily available at the project planning stage, they are very practical for TBM designers, tunnel designers, and contractors. Highlights: The correlations between the CAI and rock mechanical properties, rock mass classification parameters, and machine performance are investigated. A normalized specific energy index is proposed for assessing the performance of rocks excavation by TBMs. Several acceptable and practical estimation equations of CAI are developed using simple and multiple regression analysis. A new method for selecting optimal estimation model based on ranking is presented. [ABSTRACT FROM AUTHOR]

In order to meet the needs of pinch rollers and prolong the service life, investigations were conducted on the Stellite delstain-442 built-up welding layers in use and the proposed replacement of Stellite Multipass-249 and Stellite Multipass-224HC built-up welding layers. The microstructure and fracture morphology of three different materials after different heat treatment temperatures were observed. The variations of high-temperature mechanical properties under different test temperature were compared. The results indicated that the brittleness of 249 and 224HC built-up welding layers was quite high and limited their applications in pinch roll system although the anti-wear properties and surface hardness of 249 and 224HC were superior relative to 442. For now, the comprehensive performance of 442 built-up welding layers was more suitable to be applied in pinch roll system, but further modifications on 442 built-up welding layers must be carried out to gain more excellent mechanical and anti-wear properties based on sacrifice of partial plasticity through composition regulation, microstructure regulation and optimization of heat treatment. [ABSTRACT FROM AUTHOR]

Polybenzoxazines (PBz) are advanced thermosetting phenolic resins with many advantages, including producing nontoxic by-products, molecular design flexibility, minimum shrinkage, and low water absorption. Nevertheless, some issues might occur when synthesizing PBz, such as their brittleness, which necessitates the incorporation of some additives, such as adding another polymer or some nanocomposite material to enhance the performance of PBz. Polymer nanocomposites have emerged as multifaceted and advanced materials in recent years to overcome the disadvantages of PBz. The development of polymer nanocomposites has broadened the scope of possible uses for coatings and adhesives. Researchers constantly discover new methods for creating polymer nanocomposite coatings. The modification of fillers and the manufacturing processes used determine the properties of polymer nanocomposite coatings. Depending on various features and application types, polymer nanocomposite coatings can be classified into conductive, biocompatible, and intelligent nanocomposite coatings. Nanocomposite adhesives can be classified based on their specific performance features, such as structural, biomimetic, pressure-sensitive, and conductive. The use of newly produced polymer nanocomposites has become increasingly common in several areas of modern technology, including applications such as corrosion protection and accelerated regeneration of biological tissue. The use of polymer nanocomposites has resulted in a substantial revolution in coatings and adhesives. This review aims to shed light and provide information on using polybenzoxazine nanocomposites and their most recent coating implementation. [ABSTRACT FROM AUTHOR]

In order better to evaluate the brittleness of tight reservoir, some studies were conducted to build the new prediction method of brittleness index. First, mechanical properties of tight formation are obtained by triaxial mechanical tests. Subsequently, the correlation analysis between brittleness index and logging parameters was conducted to determine the potential sensitive parameters to brittleness index. Then, based on grey correlation, the initial sequence of sensitive parameters was determined and normalized. On this basis, based on the analytic hierarchy process, the two-two comparison judgment matrix of sensitive parameters was built, the weight vector was determined. Finally, the relationship model between the brittle index and sensitive parameter was established, which meant that a new prediction model of brittleness index was established. Compared with experiment measurement and elastic parameters methods, new method could also have high precision, and reflect the brittleness of reservoir, moreover not depending on the shear wave logging. Therefore, new method provides a new idea for predicting brittleness index and guidance for reservoir fracturing. [ABSTRACT FROM AUTHOR]

Poly (butylene succinate) PBS is considered one of the most interesting biodegradable polymers because of the good compromise of mechanical strength, ductility, toughness, and impact resistance. To change the properties of PBS, modified poly (butylene succinate-co-butylene adipate-co-ethylene succinate-co-ethylene adipate) (PBEAS) was developed. Meanwhile, polylactide (PLA) is one of the commercially used eco-friendly polymers but is limited for commercial applications due to its brittleness and relatively slow hydrolysis. In this study, we explore potential synergistic effects of blending PLA with PBS and PLA with PBEAS, and their properties before and after hydrolytic degradations were investigated as a function of degradation time. [ABSTRACT FROM AUTHOR]

The paper deals with the influence of the brittleness of glass fibers on the selected performance properties of the fibrous polymer composite. Understanding the fatigue behavior of fiber-reinforced plastics is desirable for exploiting their features in safe, durable, and reliable industrial components. Based on the proposed methodology, it is possible to assess the impact of material reuse on selected mechanical and rheological properties. To verify the methodology by experimental analysis, homopolymer PP reinforced with chemically grafted glass fiber (30 wt%) was selected. The proposed methodology was subsequently verified by experimental analysis and evaluated statistically. The morphology of the fracture surfaces was evaluated, and the fiber-polymer matrix adhesion was monitored at the interface of the fracture surfaces. Based on the measured and evaluated values and fracture surfaces, we can say that the brittleness of the fibers significantly affects the performance properties of the tested polymer composite. [ABSTRACT FROM AUTHOR]

Hard–brittle materials are widely used in the optics, electronics, and aviation industries, but their high hardness and brittleness make it challenging for traditional processing methods to achieve high efficiency and superior surface quality. This study aims to investigate the application of ultrasonic local resonant grinding to sapphire to improve the efficiency and meet the requirements for the optical window in the surface roughness of the material. The resonant frequency of a piezoelectric ultrasonic vibration system and the vibration amplitude of a grinding head's working face were simulated and tested, respectively. The results of ultrasonic grinding experiments showed that the local resonant system reduced the surface roughness parameter (Ra) of sapphire to 14 nm and improved its surface flatness to 44.2 nm, thus meeting the requirements for the ultra-precision grinding of sapphire. Compared with a conventional resonant system, the surface roughness of the sapphire ground with the local resonant system was reduced by 90.79%, its surface flatness was improved by 81.58%, and the material removal rate was increased by 31.35%. These experimental results showed that ultrasonic local resonant grinding has better effects than those of conventional ultrasonic grinding in improving surface quality and increasing the material removal rate. [ABSTRACT FROM AUTHOR]

The big advantage of refractory high entropy alloys (RHEAs) is their strength at high temperatures, but their big disadvantage is their brittleness at room temperature, which prevents their machining. There is a great need to classify the alloys in terms of brittle-ductile (B-D) properties, with easily obtainable ductility indices (DIs) ready to help design these refractory alloys. Usually, the DIs are checked by representing them as a function of fraction strain, ε. The critical values of DI and ε divide the DI—ε area into four squares. In the case of a successful DI, the points representing the alloys are located in the two diagonal opposite squares, well separating the alloys with (B-D) properties. However, due to the scatter of the data, the B-D separation is not perfect, and it is difficult to establish the critical value of DI. In this paper, we solve this problem by replacing the fracture strain parameter with new DIs that scale with the old DIs. These new DIs are based on the force constant and amplitude of thermal vibration around the Debye temperature. All of them are easily available and can be calculated from tabulated data. [ABSTRACT FROM AUTHOR]

Mechanical properties of multicomponent compounds are largely dependent upon the intermolecular interactions between the components and obviously on the overall crystal packing. Herein, we have shown the modulation of mechanical properties of two cocrystals between pyrogallol (PG) and isonicotinamide (INMI) by altering the stoichiometry of the components. One of the cocrystals shows elasticity and the other shows brittleness. Analysis of the crystal structures of the cocrystals revealed the difference in the intermolecular interactions and crystal packing, leading to different mechanical properties. [ABSTRACT FROM AUTHOR]

Direct current (DC) and pulsed DC tungsten inert gas (TIG) additive manufacturing processes were employed to fabricate GH4169 high-temperature alloy specimens. Upon comparing and analysing the two additive manufacturing methods, the evolution of microstructure and mechanical properties of the additively manufactured specimens were discussed. It provided a useful reference for the engineering application of pulsed DC TIG technology. The results showed that the overall forming process of the specimen was relatively stable under the DC TIG additive manufacturing and pulsed DC TIG additive manufacturing processes. The aspect ratio of the deposited layer of the pulsed DC-deposited specimen was relatively low, and the deposited layer of the pulsed DC specimen became flatter, which was conducive to maintaining the stability of the molten pool during the deposition process and improving forming accuracy. The microstructure distribution of the deposited layer from bottom to top was relatively uneven, with columnar dendrites in the bottom layer, cellular crystals in the middle layer, and equiaxed crystals in the top layer. Compared with the DC TIG additive manufacturing of GH4169 high-temperature alloy specimens, the Laves phase of the pulsed DC specimens was significantly reduced, which improved the plasticity and brittleness of the material. [ABSTRACT FROM AUTHOR]

This article focuses on the friendships that young refugees make in Germany as their country of arrival. Although friends are highly relevant in children's lives, little attention has been paid to this subject regarding young refugees. We conducted ego‐network interviews with 17 young refugees aged 9–15, with which we explored the opportunity structures in which young refugees choose their friends and their ways of establishing and deepening friendships, as well as the limitations thereof. Core dimensions of friendship, as proposed by Shmuel Eisenstadt, are used as sensitizing concepts: voluntariness, moral quality, unconditionality, trust, deep meaning/brittleness, and ambivalence. By reinterpreting them through an interactionist lens, the analysis reveals the complex work young refugees invest into making friends and establishing themselves in the social world of their school and peer groups. [ABSTRACT FROM AUTHOR]

Bioactive ceramic bone scaffolds are limited by their brittleness. To address this limitation, we developed a new method for preparing β-tricalcium phosphate (β-TCP)/polycaprolactone (PCL) porous composite scaffolds with a gradient structure using digital light processing technology and an impregnation process. The composite scaffolds exhibited compressive strength comparable to that of pure β-TCP scaffolds but with substantially higher toughness and reliability, especially during in vitro degradation. Owing to the gradient structure, the composite scaffolds could gradually shift from high strength and stiffness to moderate strength and low stiffness, which is beneficial for bone healing and remodeling. In femoral condyle defects without mechanical stimulation, the β-TCP/PCL composite scaffolds exhibited slightly lower cellular compatibility and osteoinductive ability than those of the pure β-TCP scaffolds. However, in radial defects, composite scaffolds demonstrated a better mechanical response and bone growth capacity. The composite scaffolds maintained their structural integrity after 2–4 months, whereas the β-TCP scaffolds fractured within 2 months. This study provides a novel methodology for the development of effective scaffold fabrication strategies for load-bearing or large segmental defects with complex stress applications for use in bone healing and remodeling. [ABSTRACT FROM AUTHOR]

Forming is limited for many modern materials due to their brittleness. Recent publications propose therefore partial heating of the forming areas, e.g., with laser technology, however, without asking how to minimize the applied energy. This work discusses such an optimization of the temperature distribution to save energy, to avoid unnecessary changes of the material properties, and to minimize thermally induced deformations. The findings are demonstrated on a statically determined quasi 1D‐problem, namely, 3‐point‐bending, and showed for a certain material law (modelling a dual phase steel of type DP1000) that the concentration of heat on the central line of the forming area is counter‐productive and that the necessary energy can be significantly reduced with a well‐defined heating strategy. Furthermore, we discuss how to extend the analysis to more complex problems which can be treated only numerically. [ABSTRACT FROM AUTHOR]

Due to the intrinsic brittleness of ceramics, it is challenging to shape and plastically deform them. In this study, we plastically deformed ZrO 2 -SiO 2 dual-phase nanocrystalline ceramics (DPNCs) by an oscillatory pressure-assisted hot forging method, termed as "dynamic hot forging" (DHF). Under the synergistic effects of oscillatory pressure (60 ± 5 MPa, 2 Hz) and heat (1250 °C), significant dimensional changes of the DPNCs occurred after DHF. The as-sintered DPNCs consisted of tetragonal ZrO 2 nanocrystallites (NCs) embedded in an amorphous SiO 2 matrix. The forging process did not significantly alter the phase composition of the DPNCs, but obvious coarsening of ZrO 2 NCs occurred during DHF. Microstructural observations showed that the DPNCs deformed predominately through the viscous flow of amorphous SiO 2 at high temperature. No microcracks were observed although the DPNCs experienced large deformation. The morphology of ZrO 2 NCs did not significantly changed, i.e., they maintained a near-spherical morphology before and after forging. However, a large number of lattice defects in ZrO 2 NCs were formed due to forging, including edge dislocations, subgrain boundary, nanotwins, and stacking faults. The formation of lattice defects did not cause significant effect on the microhardness of the DPNCs. The results of this study suggest that DHF process is a promising technique to plastically deform and shape ceramics with crystalline-amorphous dual-phase microstructure. [ABSTRACT FROM AUTHOR]

DFT approach was employed to examine the mechanical and optoelectronic properties of CdCe2X4 (X = S, Se) for investigating their fundamental attributes leading to the FM semiconducting capabilities. In this letter, we computed the precise spin-polarized electrical characteristics using mBJ potential and evaluated the physical and mechanical features via PBEsol-GGA functional. The materials' brittleness has been disclosed by the obtained elastic parameters and related components. According to the analysis of band structure configuration and density of states plots, the aforementioned composites are accounted to be the most durable. In the FM phase, these compounds’ durability is because of rare earth Ce ions’ exchange splitting within the crystal structure, which is prompted by p-d hybridization. Band exchange splitting has been significantly affected by the participation among impurity cations and resident anions as well as by their spin, charge, and magnetism. In addition, the present study entailed a thorough analysis of the dielectric parameter, which in turn gained insight into the compound's spectral behavior. FM semiconducting features played vital role in scientific improvements of photovoltaic appliances. The parameters estimated in the current investigation might help scientists to explore modifications in the functionality of CdCe2X4 (X = S, Se). [ABSTRACT FROM AUTHOR]

The analysis of the main factors of brittleness is an important basis for the selection of engineering desserts in shale oil reservoirs. In this study, with the shale oil reservoir of the Liushagang Formation in the X Depression of the Beibuwan Basin as the research object, a characterization and analysis of the main factors of brittleness of the reservoir was performed in order to further reveal the brittleness of shale reservoirs in the study area. The brittleness of reservoirs in the study area was controlled by both internal and external factors, and the main factors of brittleness in the target section included the maturity of organic matter, horizontal stress difference, and brittle minerals. As the maturity of organic matter increased, the density, elastic modulus, and hardness of casein increased and the differentially hardened internal structure occurred and significantly affected brittleness. The mineral composition of the reservoir was characterized by complex mineral types and high contents of brittle minerals, and the minerals determining brittleness were mainly quartz, feldspar, calcite, and dolomite. The horizontal stress difference of the shale oil section was relatively small and contributed to fracturing and reforming. This study clarified the brittleness characteristics of E2l shale and its main factors, and provided a basis for the selection of shale formation geo-engineering dessert layers in the study area. [ABSTRACT FROM AUTHOR]

In order to study the deformation and damage characteristics of the limestone specimens with high strength and brittleness under constant amplitude cyclic loading, the deformation and the acoustic emission (AE) characteristics were analysed, and the relationship between them was sought. The damage variables under different amplitude cyclic loading were defined by AE counts. The results showed that the radial deformation of the limestone specimens was more sensitive and unstable than the axial deformation. The concept of apparent residual strain was proposed to describe the specimen deformation characteristics, and it resulted that the radial apparent residual strain produced at higher stress state would recover at lower stress state. The limestone specimens showed obvious Kaiser effect and Felicity effect under cyclic loading. When the upper limit of the cyclic loading was close to the peak stress of the specimen, the AE counts generated in unloading sections were almost the same as that in the loading sections. The damage was increased as the amplitude and the stress level increased and the unloading process at higher stress level would also lead to the aggravation of damages. Specimens would absorb more energy under cyclic loading than under uniaxial loading. Reasonable driving parameters should be controlled in underground excavation practice, to ensure that the stress level of surrounding rock mass in a periodic stress state is located before peak stress and such that to limit the occurrence of rock burst to a certain extent. [ABSTRACT FROM AUTHOR]

The brittleness index, as the most important parameter for brittleness evaluation, directly affects the compressibility of unconventional reservoirs. Currently, there is no unified calculation method for the brittleness index. This article uses a three-axis rock mechanics servo testing system to test the rock mechanics parameters of shale oil reservoirs in Block Y of the Ordos Basin and uses an X'Pert PRO X-ray diffractometer to test the rock mineral composition. The average volume fraction of quartz minerals, feldspar, and clay minerals in 36 samples of Block Y was tested to be 22.6%, 51.6%, and 18%, respectively. Calcite, dolomite, and pyrite are only present in a few samples. When the confining pressure is 30 MPa, the elastic modulus of the Chang 7 shale in this block is 14.72–34.58 GPa, with an average value of 23.77 GPa; The Poisson's ratio ranges from 0.106 to 0.288, with an average of 0.182; The differential stress ranges from 100.8 to 260.1 MPa, with an average of 164.36 MPa; The peak strain ranges from 0.57 to 1.21, with an average of 0.91. This article compares several mainstream brittle index evaluation methods and identifies the most suitable brittle index evaluation method for Block Y. Using the Jarvie mineral composition method to calculate the brittleness index 1 (MBI), the average value of 36 experimental results is 0.5393. Using the Rickman normalized Young's modulus and Poisson's ratio average value to calculate the brittleness index 2 (EBI), the average value of 36 experimental results is 0.5204. Based on the stress-strain curve and energy method, a model for brittleness index 3 (DBI) is established, and the average value of 36 experimental results is 0.5306. The trend of the brittleness index calculated by the three methods is consistent, indicating the feasibility of the newly established brittleness evaluation method. From the perspectives of mineral composition, rock mechanics parameters, and energy, establishing a brittleness evaluation method for shale oil reservoirs and studying its evaluation method is of great significance for sweet spot prediction in reservoir engineering, providing theoretical support for the selection of fractured intervals in the Chang 7 shale oil reservoir in Block Y of the Ordos Basin. [ABSTRACT FROM AUTHOR]

Traditional fabrication of ceramic parts face limitations due to hardness and brittleness, despite of having good mechanical properties. Digital light processing (DLP) additive manufacturing technology offers promising way to fabricate intricate geometry of ceramic parts. To fabricate high performance, maximizing solid loading of ceramic powder is important to reduce the shrinkage and distortion during post-processing. However, it increases viscosity dramatically and makes difficult with material supply during printing process. Therefore, not only increasing the solid loading of ceramic powder but also minimizing random defects during printing process is essential for us to achieve high-quality ceramic parts. In this study, vision-based defect monitoring system using Mask R-CNN model was employed. We classified two types of defects called pinhole and un-even paste and quantify the defect characteristics such as number and size with pixel level. This method provides us the basis of a feed-back system for controlling the process parameters in real time. [ABSTRACT FROM AUTHOR]

Contour error is a crucial quality measure for stone relief products. Achieving the appropriate process parameters is vital due to the inherent hardness, brittleness, and natural crystal defects found in white marble. This study investigated various processing characteristics of Chinese character stone relief and primarily focused on understanding the impact of spindle speed, feed speed, milling width, and milling depth on contour error. The study optimized the process parameters by considering the contour error as the response target. Firstly, the paper outlined the machining process of stone relief using a manipulator and provided a classification basis for different machining features. Subsequently, a series of white marble milling experiments were conducted using the Box-Behnken design method of Response Surface Methodology (RSM). A multiple nonlinear regression model was established to analyze the influence of various processing characteristics on white marble contour error. Through RSM, the interaction effects of different factors on the contour error were examined. Finally, optimal milling parameters were selected and validated through experiments. The results indicated that the optimized milling process proposed in this study can reduce the contour error of the final stone relief products by 47.3% compared to traditional milling methods. [ABSTRACT FROM AUTHOR]

Materials called geopolymers are considered an alternative to common hydraulic binders, but they have certain limitations in many applications due to their brittleness. The use of fibers to reinforce geopolymers can bring the expected results by increasing their compressive strength. This paper presents the results of accelerated durability tests of geopolymers based on coal shale and fly ash reinforced with natural fibers (1% by mass). The results of testing the resistance of such composites to UV radiation, variable temperature cycles and the results of the thermal conductivity coefficient are presented. [ABSTRACT FROM AUTHOR]

Yingxiongling shale oil is considered a critical area for future crude oil production in the Qaidam Basin. However, the unique features of the Yingxiongling area, such as extraordinary thickness, hybrid sedimentary, and extensive reformation, are faced with several challenges, including an unclear understanding of the main controlling factors for hydraulic fracturing propagation, difficulties in selecting engineering sweet layers, and difficulties in optimizing the corresponding fracturing schemes, which restrict the effective development of production. This study focuses on mixed fine-grained sedimentary rocks, employing a high-resolution integrated three-dimensional geological-geomechanical model to simulate fracture propagation. By combining laboratory core experiments, a holistic investigation of the controlling factors was conducted, revealing that hydraulic fracture propagation in mixed fine-grained sedimentary rocks is mainly influenced by rock brittleness, natural fractures, stress, varying lithologies, and fracturing parameters. A comprehensive compressibility evaluation standard was established, considering brittleness, stress contrast, and natural fracture density, with weights of 0.3, 0.23, and 0.47. In light of the high brittleness, substantial interlayer stress differences, and localized developing natural microfractures in the Yingxiongling mixed fine-grained sedimentary rock reservoir, this study examined the influence of various construction parameters on the propagation of hydraulic fractures and optimized these parameters accordingly. Based on the practical application in the field, a "three-stage" stimulation strategy was proposed, which involves using high-viscosity fluid in the front to create the main fracture, low-viscosity fluid with sand-laden slugs to create volume fractures, and continuous high-viscosity fluid carried sand to maintain the conductivity of the fracture network. The resulting oil and gas seepage area corresponding to the stimulated reservoir volume (SRV) matched the actual well spacing of 500 m, achieving the effect of full utilization. The understanding of the controlling factors for fracture expansion, the compressibility evaluation standard, and the main process technology developed in this study effectively guide the optimization of transformation programs for mixed fine-grained sedimentary rocks. [ABSTRACT FROM AUTHOR]

In the process of roadway excavation in thick and hard coal seams with a hard roof, the instantaneous release of a large amount of elastic energy accumulated in coal and rock mass causes disasters. Especially under the action of tectonic stress, dynamic disasters of roadway-surrounding rock are extremely strong. Therefore, this paper takes the 110,505 roadway of the Yushuling Coal Mine as the engineering background. Aiming at the serious deformation of roadway-surrounding rock and the problem of strong mine pressure, the deformation mechanism of roadway-surrounding rock is studied by means of theoretical analysis, indoor experimentation, numerical simulation and field testing, and the surrounding rock control technology is proposed. Firstly, the results show that the stress field type of the Yushuling Coal Mine is a σ H v type, the azimuth angle of the maximum horizontal principal stress is concentrated in 110.30°~114.12°, the dip angle is −33.04°~−3.43°, and the maximum horizontal principal stress is 1.94~2.76 times of the minimum horizontal principal stress. Secondly, the brittleness index of No. 5 is 0.62; the failure energy release of the surrounding rock compressive energy floor rock sample is up to 150,000 mv * ms. The more the cumulative number of rock samples, the greater the strength, and the more severe the damage. Thirdly, with the increase in tectonic stress, the stress of roadway-surrounding rock is asymmetrically distributed, and the plastic zone develops along the tendency. The maximum range of the plastic zone expands from 4.18 m to 10.19 m. Lastly, according to the deformation characteristics of roadway-surrounding rock, left side > roof > right side > floor, the surrounding rock control technology of 'asymmetric anchor net cable support + borehole pressure relief' is proposed, which realizes the effective control of roadway-surrounding rock deformation. [ABSTRACT FROM AUTHOR]

Geopolymers assume an irreplaceable position in the engineering field on account of their numerous merits, such as durability and high temperature resistance. Nevertheless, geopolymers also demonstrate brittleness. In this study, geotextiles with different layers were added to geopolymer to study its compressive strength and stability. Laboratory materials such as alkali activators, geotextiles and granite residual soil (GRS) were utilized. The samples were characterized via XRD, TG-DTG, SEM-EDS and FT-IR. The results indicate that the toughness of geopolymer is significantly enhanced by adding geotextiles, and the strength increase is most obvious when adding one layer of geotextile: the strength increased from 2.57 Mpa to 3.26 Mpa on the 14th day, an increase of 27%. Additionally, the D-W cycle has a great influence on geotextile polymers. On the 14th day, the average strength of the D-W cyclic sample (1.935 Mpa) was 1.305 Mpa smaller than that of the naturally cured sample (3.24 Mpa), and the strength decreased by 40%. These discoveries offer a novel approach for further promoting the application of geopolymers, especially in the field of foundation reinforcement. [ABSTRACT FROM AUTHOR]

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Nonaqueous flow batteries hold promise given their high cell voltage and energy density, but their performance is often plagued by the crossover of redox compounds. In this study, we used permselective lithium superionic conducting (LiSICON) ceramic membranes to enable reliable long-term use of organic redox molecules in nonaqueous flow cells. With different solvents on each side, enhanced cell voltages were obtained for a flow battery using viologen-based negolyte and TEMPO-based posolyte molecules. The thermoplastic assembly of the LiSICON membrane realized leakless cell sealing, thus overcoming the mechanical brittleness challenge. As a result, stable cycling was achieved in the flow cells, which showed good capacity retention over an extended test time. [ABSTRACT FROM AUTHOR]