Young's Modulus Values Research Articles

Evolution of Mechanical Properties of Pb–Sb–Sn–As–Se Grid Alloys for Lead-Acid Batteries During Natural Aging

This study is devoted to the investigation of mechanical properties of a series of low-antimony Pb–Sb–Sn–As–Se grid alloys for lead-acid batteries in as-cast condition and after natural aging during storage. Mechanical properties were characterized by ultimate tensile strength, yield strength, elongation, and Young's modulus determined at room temperature using TIRAtest 2300 and P-0.5 universal testing machines. For most investigated as-cast alloys, an increase in ultimate tensile strength is accompanied by an increase in elongation. Within the temperature range between 70 ºС and 150 ºС, higher heating temperature of a casing mold does not markedly affect average elongation but causes the slight decrease (by ~4 %) in average ultimate tensile strength. When aged during storage for 30–33 days, the Pb–Sb–Sn–As–Se grid alloys, attain higher values of ultimate tensile strength, yield strength, and Young's modulus but lower values of elongation. This is due to precipitation of second-phase particles from lead-based solid solution oversaturated by antimony, arsenic, and selenium. The most noticeable effect of strengthening is observed during first five days of natural aging.

Using Renal Elastography to Predict the Therapeutic Response of Nephrological Patients

Background: The standard method for assessing chronic renal damage is renal biopsy, which has limitations due to its invasiveness. Ultrasound elastography is a non-invasive technique that quantifies tissue elasticity and can be used to determine Young’s modulus (YM). Although this breakthrough technology has been successfully employed to evaluate liver stiffness and the extent of fibrosis, its application in kidney-related conditions still needs improvement. Methods: Our study aimed to verify the correlation between renal elastography and the chronic histological score determined via renal biopsy, evaluate the correlation between elastography and response to treatment in the short-term follow-up (6 months), and compare elastography data between renal disease patients (AKD-P) and healthy controls (HP). Results: The analyzed population consisted of 82 patients (41 HP and 41 AKD-P). The AKD-P were divided into responders (R) or non-responders (NR) based on the criteria established by the guidelines. No association was found between renal stiffness and chronic histological score. Elastography data revealed median YM values of 6.15 kPa for AKD-P and 12.2 kPa for HP, with a statistically significant difference. The median YM values of the R and NR groups were 7.4 KPa and 5.6 KPa, respectively (p = 0.037). Conclusions: Patient responsiveness was associated with YM, with lower values observed in the NR group. We also found that the healthy controls exhibited significantly higher YM values than the renal disease population.

Effects of Hybrid POSS Nanoparticles on the Properties of Thermoplastic Elastomer-Toughened Polyamide 6.

In this study, polyamide 6 (PA6)/thermoplastic elastomer (TPE) blends were prepared to decrease the notch sensitivity of PA6 for automotive applications, and the morphological, rheological, mechanical, and thermal properties of PA6/TPE blends, which are partially miscible or immiscible depending on the TPE ratio, were significantly improved in the existence of polyhedral oligomeric silsesquioxane (POSS) nanoparticles with multiple reactive epoxy groups as compatibilizers. An unstable phase morphology was obtained with the addition of TPE into PA6 without POSS nanoparticles, whereas interfacial interactions between phases in the presence of POSS were enhanced as a result of a significant decrease in the average particle size from 1.39 to 0.41 μm. The complex viscosity value of the 70PA6/30TPE blend, which was 20 kPa/s-1 at 0.1 rad/s angular frequency, reached 380 kPa/s-1 with the addition of POSS due to the formation of long chains by the generation of graft and/or block copolymers, which resulted in a 65% increase in Young's modulus value. Most notably, the Izod impact strength of pure PA6, which was 10 kJ/m2, increased by 290% with the incorporation of POSS. It was confirmed by FTIR analysis that the reactive multiple epoxy groups of MultEpPOSS and EPPOSS nanoparticles react with the proper groups of PA6 and/or TPE, and also, a partial hydrogen bonding interaction occurs between PA6-TPE from the shifting of N-H and carbonyl peaks. In conclusion, it can be suggested that POSS nanoparticles can serve as highly effective compatibilizers for PA6/TPE blends and have potential commercial applications, especially in the automotive sector.

Microstructural and mechanical properties evolution of (Ti0.8W0.2)C powders after sintering by the SPS technique

The Ti0.8W0.2C alloys were sintered at different temperatures after being synthesized by mechanical alloying for a grinding time of 10 and 20 h. The temperatures used to perform the sintering of the samples were 1100, 1135, 1150 and 1240 °C for a holding duration of 5 min and under a pressure of 100 MPa. XRD patterns demonstrate that a thermal decomposition has occurred for the Ti0.8W0.2C powders sintered at all temperatures. For the two milling duration, the SEM analysis showed a dense microstructure with the presence of pores in a very small quantity for the sintering at 1150 °C. For the consolidated carbides after 10 h milling, the fluctuations in the lattice parameter of the (Ti0.8W0.2)C carbide could be attributed to the effective internal strain variation in the material. The relative density, micro-hardness and diffraction crystallite size (DCS) increased with sintering temperature. So, the variation in hardness does not follow the Hall–Petch relationship. For a DCS of 25 nm, the relative density and micro-hardness of the consolidated carbide, treated at the optimal temperature of 1240 °C after 10 h MA, reached respectively 93.53% and 2719 HV. Thus, the micro-hardness is mainly related to the variation of porosity, rather than to the variation of diffraction crystallite size. The highest Young's modulus value (406.78 GPa) is obtained at sintered temperature of 1240 °C after 10 h of milling.

Polycaprolactone-Based Films Incorporated with Birch Tar-Thermal, Physicochemical, Antibacterial, and Biodegradable Properties.

We present new polymer materials consisting of polycaprolactone (PCL), polyethylene glycol (PEG), and birch tar (D). PEG was introduced into the polymer matrix in order to obtain a plasticizing effect, while tar was added to obtain antibacterial properties and to change the physicochemical properties of the film. The materials were obtained by the solvent method and characterized using a variety of methods to test their performance and susceptibility to biodegradation. The obtained data indicate that the introduction of the bioactive substance (D) into PCL improved the thermal stability and significantly lowered the Young's modulus values of the tested polymers. Moreover, the addition of birch tar improved the barrier and bacteriostatic properties, resulting in a reduction in the growth of pathogenic bacteria on the surface of the film. The films are not mutagenic but are susceptible to biodegradation in various environments. Due to their properties, they have potential for application in agriculture and horticulture and for packaging food, mainly vegetables grown in the field.

Fabrication of continuous woven E-glass fiber composite using vat photopolymerization additive manufacturing process

PurposeThe industrial application of continuous glass fabric-reinforced polymer composites (GFRPCs) is growing; however, the manufacturing boundedness of complex structures and the high cost of molds restrict their use. This research proposes a three-dimensional (3 D) printing process for GFRPCs that allows low-cost and rapid fabrication of complex composite parts.Design/methodology/approachThe composite is manufactured using a digital light processing (DLP) based Vat-photopolymerization (VPP) process. For the composites, suitable resin material and glass fabrics are chosen based on their strength, stiffness, and printability. Jacob's working curve characterizes the curing parameters for adequate adhesion between the matrix and fabrics. The tensile and flexural properties were examined using UTM. The fabric distribution and compactness of the cured resin were analyzed in scanning electron microscopy.FindingsThe result showed that the object could print at a glass fabric content of 40 volume%. In DLP-based VPP printing technology, the adequate exposure time was found to be 30 seconds for making a GFRPC. The tensile strength and Young's modulus values were increased by 5.54 and 8.81 times, respectively than non-reinforced cured specimens. The flexural strength and modulus were also effectively increased to 2.8 and 3 times more than the neat specimens. In addition, the process is found to help fabricate the functional component.Originality/valueThe experimental procedure to fabricate GFRPC specimens through DLP-based AM is a spectacular experimental approach.

DEVELOPMENT OF AN OPEN-SOURCE FINITE ELEMENT ANKLE MODEL FOR IN-SILICO INVESTIGATION OF THE ANKLE JOINT

AbstractObjectivesThis abstract provides an update on the Open Ankle Models being developed at the University of Bath. The goal of this project is to create three fully open-source finite element (FE) ankle models, including bones, ligaments, and cartilages, appropriate musculoskeletal loading and boundary conditions, and heterogeneous material property distribution for a standardised representation of ankle biomechanics and pre-clinical ankle joint analysis.MethodsA computed tomography (CT) scan data (pixel size of 0.815 mm, and slice thickness of 1 mm) was used to develop the 3D geometry of the bones (tibia, talus, calcaneus, fibula, and navicular). Each bone was given the properties of a heterogeneous elastic material based on the CT greyscale. The density values for each bone element were calculated using a linear empirical relation, ρ= 0.0405 + (0.000918) HU and then power law equations were utilised to get the Young's Modulus value for each bone element [1]. At the bone junction, a thickness of cartilage ranging from 0.5–1 mm, and was modelled as a linear material (E=10 MPa, ν=0.4 [2]). All ligament insertions and positions were represented by four parallel spring elements, and the ligament stiffness and material attributes were applied in accordance with the published literature [2]. The ankle model was subjected to static loading (balance standing position). Four noded tetrahedral elements were used for the discretization of bones and cartilages. All degrees of freedom were restricted at the proximal ends of the tibia and fibula. The ground reaction forces were applied at the underneath of the calcaneus bone. The interaction between the cartilages and bones was modelled using an augmented contact algorithm with a sliding elastic contact between each cartilage. A tied elastic contact was used between the cartilages and the bone. FEbio 2.1.0 (University of Utah, USA) was used to construct the open-source ankle model.ResultsWhen the double-legged stance phase loading condition was taken into consideration, stress at the antero-medial tibial wall (ranged from 1 to 7 MPa) was found to be similar to the prior work [2], indicating bulk of the load transfer was through this region. The maximum principal strain was predicted at the different regions on bones around the ankle joint. The proximal surface of the talus, and tibial distal surface were shown to have the highest maximum principal strains followed by antero-medial walls of the tibia bone, at the proximal location.ConclusionsThe present open 3D FE model of the ankle will assist researchers in better understanding ankle biomechanics, precisely predicting load transfer, and examining the ankle to address unmet clinical needs for this joint. The results of the current investigation are realistic in terms of load transfer and stress-strain distribution across the ankle joint and well comparable to those reported in the literature [2]. However, sensitivity and ankle instability simulations will be performed in future work to investigate the model's reliability and robustness.Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Role of Shear Wave Elastography in the Diagnosis of Peyronie Disease.

The present study aims to explore the role of shear wave elastography (SWE) in the diagnosis of Peyronie disease (PD). A total of 59 PD patients and 59 age-matched healthy adult men were included in this study. The B-mode ultrasound (US) and SWE were performed for all subjects, and the Young modulus (YM) values of the corresponding regions of the penis in the PD and control groups were recorded and compared. The mean age of the included PD patients and age-matched controls was 53.81 years (SD 9.52, range 32-73). On B-mode US evaluation, 41 (69.5%) of 59 included PD patients were found to have penile plaques, and the remaining 18 (30.5%) patients had no evidence of penile plaque. After evaluation using SWE, the YM values in the penile plaque region of these 41 patients with penile dysplasia were found to be significantly higher (60.29 kPa ± 19.95) than those outside the plaque (in the same patient) (21.05 kPa ± 4.58) and in the same penile region of the control group (20.59 kPa ± 4.65) (P < .001). In the remaining 18 PD patients, the results showed that the YM value of the abnormal penile region in the PD patients (56.67 kPa ± 13.52) was significantly higher than the YM value outside the abnormal penile region in the same patients (22.79 kPa ± 4.31) and in the same penile region in the control group (19.87 kPa ± 3.48) (P < .001; P < .001). In conclusion, this study showed that SWE as a non-invasive technique is useful in identifying and differentiating penile plaques in PD patients and is a simple, rapid and complementary method to B-mode US.

EFFECTS OF REINFORCEMENT RATIO ON PHYSICAL AND MECHANICAL PROPERTIES OF CORN SILK REINFORCED EPOXY COMPOSITE

Corn silk known as the waste product that can contribute to bad pollution neither air nor land. Therefore, corn silk was introduced as a nature fibre reinforcement in composite which can contribute to the positive environmental issues while developing new composite materials. 4 samples were fabricated by different composition at 0% to 6vol% employing the hand lay-up technique by mixing the natural fibre with epoxy and hardener at fixed ratio. The objective of this experiment was to fabricate the sample of composite materials with different reinforcement ratio of corn silk with epoxy and study their effects on physical and mechanical properties. Sample size prepared following ASTM DT 3039 standard (250mm X 25mm X 3mm) for tensile test. Tests conducted shows that the hardness were increase while the density value were fluctuating by increasing corn silk reinforcement ratio. The highest hardness and density values reflect on 6 vol% with 20.5 HV and 2 vol% with 1.22 g/cm3 respectively. The result revealed the highest strength achieved by 0% of fibre with 22.6458 MPa and lowest at 6% of fibre with 13.2146 MPa. Moreover, the highest strain achieved by 0% of fibre with 1.085% and lowest at 6% of fibre with 0.6894% the pattern of result shows the value of strength and strain is increasing by decreasing the percentage of the fibre. The highest value of young's modulus achieved by 0% of fibre with 21.9742 MPa and for the lowest value of young's modulus at 6% of fibre with 18.8985 MPa.

MoO3 nanoplates reinforced the structural, electrical, mechanical, and antibacterial characteristics of polyvinyl pyrrolidone/sodium alginate polymer blend for optoelectronics and biological applications

Organic/Inorganic nanostructures enable the development of new functional materials for optoelectronics and biological applications. In this work, nanocomposite films of polyvinyl pyrrolidone (PVP) and sodium alginate (NaAlg) blend matrix (30/70 wt%) filled with molybdenum trioxide (MoO3) nanoplates were prepared using solution casting procedure. The effect of MoO3 nanoplates on structural, optical, electrical and antibacterial characteristics of pure PVP/NaAlg blend was investigated. The sizes of MoO3 nanoplates had dimensions between 90 and 420 nm with orthorhombic phase as indicated by the TEM and XRD techniques. Also, the XRD patterns of filled films suggested that the presence of crystalline phases of MoO3 within PVP/NaAlg matrix. FTIR analysis revealed the primary vibrational peaks of PVP and NaAlg, whose strength altered randomly after filling. The UV absorption increased gradually and shifted to the higher wavelength side. The alternating current (AC) conductivity and dielectric parameters were improved with increasing MoO3 concentration. The antibacterial activity against Staphylococcus aureus and Escherichia coli increased with increase of MoO3 nanoplates concentration. The filled PVP/NaAlg-MoO3 samples displayed considerable enhancements in the values of Young's modulus (Y), tensile stress (σt) and elongation at break (εB). The obtained results imply that these nanocomposite films can be potentially used in optoelectronics and biological applications.

Effects of thermal ageing time and temperature during heat-treatment on the mechanical properties of fiber laser welded Nb-1%Zr-0.1%C alloy in continuous wave mode

The effects of thermal ageing time and temperature used during heat-treatment were studied on tensile strength, elongation, and microhardness of the laser welded Nb-1%Zr-0.1%C alloy in continuous wave mode. Post-weld heat treatment (PWHT) was carried out by varying the temperature and time in the ranges of (850–1050) °C (that is, about the recrystallisation temperature) and (0.5–4) h (as the weld samples were prepared in the form of sheets), respectively. The grain sizes of fusion zone (FZ), and FZ heat treated at 850 °C for 4 h and that at 950 °C for 2 h were found to be equal to 52.85 μm, 84.89 μm and 116.43 μm, respectively. The segregation of zirconium, carbon and oxygen increased grain boundary energy and induced brittleness to the grain boundary, resulting in loss of ductility. The micro-hardness and Young's modulus values were observed to increase in the FZ compared to that of the base metal (BM), but their decreasing trends were noticed during the heat-treatment due to the grains' softening. For the PWHT samples, the plasticity was found to decrease to about 57% of that of BM. This was attributed to the precipitation of carbides, grain growth, and dislocation pinning during the ageing process. During the heat-treatment of the welded samples, both Yield Strength (YS) and Ultimate Tensile Strength (UTS) were found to decrease to 77% and 86%, respectively, of that of the BM.

ANALISIS UJI TARIK KOMPOSIT SERAT BATANG KELAKAI DENGAN VARIASI KATALIS UNTUK PEMBUATAN MATERIAL BUMPER MOBIL

A research was conducted to create car bumper materials using natural kelakai plant fibers combined with a catalyst and resin as a binding agent in the composite. The main goal of the study was to examine the tensile strength of the kelakai fiber composite with different catalyst variations and assess the impact of these catalyst changes on the bumper material's tensile strength. The composite materials were prepared in three test specimens with catalyst compositions of 2,5%, 5%, and 7,5%, respectively, based on a 20 mL resin composition. These samples underwent tensile testing using a Universal Testing Machine (UTM). The results revealed that the tensile strength of the kelakai fiber composite increased with higher catalyst percentages. At 2,5%, 5%, and 7,5% catalyst compositions, the tensile strengths were measured as 0,37 N/mm2, 0,41 N/mm2, and 0,47 N/mm2, respectively. Additionally, the elongation values for the catalyst portion are 1,11%, 2,22%, and 3,89% and the Young's modulus values are 0,33 N/mm2, 0,18 N/mm2, and 0,12 N/mm2, respectively. The study demonstrates the significant influence of catalyst variations on the tensile strength of the kelakai fiber composite.

First-Principle Investigation of La0.7Ba0.3Mn(1-x)FexO3 Structural Properties Using CASTEP

&lt;p&gt;We conducted first-principles Density Functional Theory (DFT) calculations using the CASTEP software package to investigate the crystal structure and mechanical properties of Fe&lt;sup&gt;3+&lt;/sup&gt;-doped La&lt;sub&gt;0.7&lt;/sub&gt;Ba&lt;sub&gt;0.3&lt;/sub&gt;MnO&lt;sub&gt;3&lt;/sub&gt; material at the Mn&lt;sup&gt;3+&lt;/sup&gt; site, with doping concentrations ranging up to 50%. Through geometry optimization, we simulated the X-ray diffraction (XRD) pattern. We observed that the doping of Fe did not result in a shift in the peak positions of the diffraction pattern. However, it led to an increase in intensity at the [012] peak and the splitting of peaks [104] and [110]. Regarding the mechanical properties, we examined the elastic constants and observed a reduction in the Bulk, Shear, and Young's modulus values. The Shear and Bulk modulus and Poisson's ratio indicated that La&lt;sub&gt;0.7&lt;/sub&gt;Ba&lt;sub&gt;0.3&lt;/sub&gt;Mn&lt;sub&gt;(1-x)&lt;/sub&gt;Fe&lt;sub&gt;x&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; becomes less ductile with increased Fe&lt;sup&gt;3+&lt;/sup&gt; doping content. Furthermore, we performed calculations for the Debye temperature, which revealed a decrease in the thermal conductivity of the La&lt;sub&gt;0.7&lt;/sub&gt;Ba&lt;sub&gt;0.3&lt;/sub&gt;Mn&lt;sub&gt;(1-x)&lt;/sub&gt;Fe&lt;sub&gt;x&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; material.&lt;/p&gt;&lt;p class="Abstract"&gt; &lt;/p&gt;

Porosity dependence of sound velocities in partially sintered alumina, zirconia, ATZ, and mullite ceramics

AbstractYoung's modulus and sound velocities of partially sintered alumina, zirconia, ATZ, and mullite ceramics with a broad range of porosities determined via the impulse excitation technique (IET) and the ultrasonic wave propagation pulse‐echo technique (UPT) are found to be in good agreement and exhibit sigmoidal curves as a function of the sintering temperature. The porosity dependence of the relative values of Young's modulus and sound velocities is either close to or below (but never above) the prediction based on an exponential relation, and none of them is significantly below the prediction based on a percolation relation or a recently proposed numerical benchmark relation for overlapping monosized spheres. Values are lower when concave pores or irregular anisometric grains are dominating. The correlation of the normalized longitudinal wave velocities and relative transverse wave velocities, with VL/VT ratios ranging from 0.50 to 1.91, is well predicted by models for Poisson's ratios between 0.35 and 0.2.

Anisotropy, Anatomical Region, and Additional Variables Influence Young's Modulus of Bone: A Systematic Review and Meta-Analysis.

The importance of finite element analysis (FEA) is growing in orthopedic research, especially in implant design. However, Young's modulus (E) values, one of the most fundamental parameters, can range across a wide scale. Therefore, our study aimed to identify factors influencing E values in human bone specimens. We report our systematic review and meta-analysis based on the recommendation of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guideline. We conducted the analysis on November 21, 2021. We included studies investigating healthy human bone specimens and reported on E values regarding demographic data, specimen characteristics, and measurement specifics. In addition, we included study types reporting individual specimen measurements. From the acquired data, we created a cohort in which we performed an exploratory data analysis that included the explanatory variables selected by random forest and regression trees methods, and the comparison of groups using independent samples Welch's t test. A total of 756 entries were included from 48 articles. Eleven different bones of the human body were included in these articles. The range of E values is between 0.008 and 33.7 GPa. The E values were most heavily influenced by the cortical or cancellous type of bone tested. Measuring method (compression, tension, bending, and nanoindentation), the anatomical region within a bone, the position of the bone within the skeleton, and the bone specimen size had a decreasing impact on the E values. Bone anisotropy, specimen condition, patient age, and sex were selected as important variables considering the value of E. On the basis of our results, E values of a bone change with bone characteristics, measurement techniques, and demographic variables. Therefore, the evaluation of FEA should be performed after the standardization of in vitro measurement protocol. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Effect of thermal, mechanical and photophysical properties of high emissive photoluminescence organic pigments

This research aims to synthesize highly visible, bright emission fluorescent dye molecules in daylight to produce PU films and PU resource safety materials. Here we have developed four different types of highly visible PU films in which a cyano-substituted methoxyphenylene core with an additional electron-withdrawing and-donating unit is used to produce a bright orange color with twisted rigid conformational dyes. Modifications in the mechanical behavior and thermal stability properties of PU films were tested by tensile tests, TGA and DSC. The samples of PU film exhibit exceptional elasticity, with a high elongation breaking point and good young's modulus value. Furthermore, these synthesized dyes were measured for photophysical properties and other parameters such as solvent effect, quantum yield and lifetime. The quantum yields of highly visible dyes were measured in both solution and solid phase and found to be in the range of 0.25–0.48 and 0.15 to 0.55, respectively. The HOMO-LUMO energy gap of the dyes in the solid state is significantly lower than that in the solution state. This related to the dyes which exhibiting a lifetime in THF solution of about 1.96–2.41 ns, whereas in the solid state, the lifetime is much better about 6.43–19.61 ns. This indicating that the dyes in the solid state are energetically easier and hence the solid state of dyes shows higher lifetime.

Multi-analytical investigation of the physical, chemical, morphological, tensile, and structural properties of Indian mulberry (Morinda tinctoria) bark fibers

In this study, micro-cellulosic fibers were isolated from the bark of Morinda tinctoria (MT) and characterized for the first time. The anatomical, physical, chemical, thermal, and mechanical properties of the M. tinctoria bark fiber (MTBF) were investigated. The mean diameter and density values were determined to be 32.013 ± 1.43 μm and 1.4875 g/cm³, respectively. Zeta potential analysis and particle size measurements provided the evidence of enhanced micro-particle behavior on the fiber's surface. Various structural characterizations confirmed the presence of polysaccharide structures, monosaccharide compositions, glycosidic residues (sugar linkages), and cohesive reactions of TMSA (Trimethylsilyl alditol) derivatives, indicating the fiber's potential for strong surface absorption properties. X-ray diffraction analysis revealed a crystallinity index of 51 % and a crystallite size of 3.086 nm for MTBF. Fourier transform infrared analysis indicated the presence of cellulose, hemicellulose, and lignin constituents, along with their corresponding functional groups. The calculated values of Young's modulus and tensile strength were determined to be 75.7 GPa and 746.77 MPa, respectively. Thermogravimetric analysis demonstrated the thermal stability of the extracted MTBF up to 240 °C. Based on these findings, the MT microfibrils derived from the bark can be considered as potential substitutes for existing synthetic composites, offering reinforcement for novel bio composites.

Effect of carbonaceous reinforcements on mechanical properties of ZrB2-SiC composites via nanoindentation study

In the present work, silicon carbide (SiC) reinforced zirconium diboride (ZrB2) ceramic was studied. ZrB2 reinforced with 20 vol% SiC (ZS) and with additives multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and CNT + GNP were consolidated via spark plasma sintering. ZS with carbon additives (CNT + GNP) composite (ZSCG) showed the highest densification (98.2 %) than that of ZS sample (91 %) via Archimedes' method. Crystallite size calculated via XRD showed a value of (56 ± 1) for ZS and the lowest crystallite size value (47 ± 1) for ZSCG, attributed to the pinning effect of carbonaceous reinforcements (CNT + GNP) at the grain boundaries, which restrict the grain growth in the composite. Nanohardness for the composite samples ranges from ~24 to 33 GPa. ZSCG composite showed the highest nanohardness of 33 GPa attributed to the bridging of long and flexible CNTs adjacent to GNPs to form 3-D hybrid structures restricting their agglomeration, which resulted in a high interfacial area between the matrix and the hybrid reinforcement leading to better load transfer. The theoretically calculated Young's modulus from various models (rule of mixture, Voigt Reuss, and Halpin Tsai (HT)) was compared with the experimental Young's modulus. The calculated Young's modulus value via the HT model (370–411 GPa) is in close agreement with the experimental values (364–401 GPa) owing to consideration of porosity and the interfacial debonding factor. Also, the lowest debonding factor was determined for the ZSCG composite (0.47) in comparison with the ZSC composite (0.86) suggesting increased bonding strength which results in the enhancement of mechanical properties. So, it was finally concluded that the finer crystallite size, improved hardness, less debonding factor, and better load transfer mechanism can make ZSCG composite a viable candidate for high-temperature applications.

Sustainable biomass-based composite biofilm: Sodium alginate, TEMPO-oxidized chitin nanocrystals, and MXene nanosheets for fire-resistant materials and next-generation sensors

Efficient utilization of natural biomass for the development of fireproof materials and next-generation sensors faces various challenges in the field of fire safety and prevention. In this study, renewable sodium alginate (SA), TEMPO-oxidized chitin nanocrystals (TOChNs), and MXene nanosheets were employed to fabricate a sustainable, flexible, and flame-retardant composite biofilm, donated as STM, utilizing a simple and environmentally friendly evaporation-induced self-assembly technique. The incorporation of SA, TOChNs, and MXene in a weight ratio of 50/10/40 led to improved mechanical properties of the resulting STM-40 films, as evidenced by increased tensile strength and Young's modulus values of approximately 36 MPa and 4 GPa, respectively. Notably, these values were approximately 3 and 11 times higher than those observed for the pure SA film. Moreover, the STM-40 films demonstrated highly sensitive fire alarm capabilities, exhibiting a superior flame alarm response time of 0.6 s and a continuous alarm time of approximately 492 s when exposed to flames. The STM exhibited exceptional flame retardancy due to the synergistic carbonization between MXene and SA/TOChNs, resulting in a limiting oxygen index of 45.0 %. Furthermore, its maximum heat release rate decreased by over 90.1 % during the test. This study presents a novel approach for designing and developing fire-retardant fire alarm sensors by utilizing natural biomass.

Resonance of the tympanoperiotic complex of fin whales with implications for their low frequency hearing.

The tympanoperiotic complex (TPC) bones of the fin whale skull were studied using experimental measurements and simulation modeling to provide insight into the low frequency hearing of these animals. The study focused on measuring the sounds emitted by the left and right TPC bones when the bones were tapped at designated locations. Radiated sound was recorded by eight microphones arranged around the tympanic bulla. A finite element model was also created to simulate the natural mode vibrations of the TPC and ossicular chain, using a 3D mesh generated from a CT scan. The simulations produced mode shapes and frequencies for various Young's modulus and density values. The recorded sound amplitudes were compared with the normal component of the simulated displacement and it was found that the modes identified in the experiment most closely resembled those found with Young's modulus for stiff and flexible bone set to 25 and 5 GPa, respectively. The first twelve modes of vibration of the TPC had resonance frequencies between 100Hz and 6kHz. Many vibrational modes focused energy at the sigmoidal process, and therefore the ossicular chain. The resonance frequencies of the left and right TPC were offset, suggesting a mechanism for the animals to have improved hearing at a range of frequencies as well as a mechanism for directionality in their perception of sounds.