Mechanical Quality Research Articles

Slow-light-enhanced Brillouin scattering with integrated Bragg grating.

Advancements in photonic integration technology have enabled the effective excitation of simulated Brillouin scattering (SBS) on a single chip, boosting Brillouin-based applications such as microwave photonic signal processing, narrow-linewidth lasers, and optical sensing. However, on-chip circuits still require large pump power and centimeter-scale waveguide length to achieve a considerable Brillouin gain, making them both power-inefficient and challenging for integration. Here, we exploit the slow-light effect to significantly enhance SBS, presenting the first, to the best of our knowledge, demonstration of a slow-light Brillouin-active waveguide on the silicon-on-insulator (SOI) platform. By integrating a Bragg grating with a suspended ridge waveguide, a 2.1-fold enhancement of the forward Brillouin gain coefficient is observed in a 1.25 mm device. Furthermore, this device shows a Brillouin gain coefficient of 1,693 m-1W-1 and a mechanical quality factor of 1,080. The short waveguide length reduces susceptibility to inhomogeneous broadening, enabling the simultaneous achievement of a high Brillouin gain coefficient and a high mechanical quality factor. This approach introduces an additional dimension to enhance acousto-optic interaction efficiency in the SOI platform and holds significant potential for microwave photonic filters and high spatial resolution sensing.

Corn cob nanocellulose packaging for increasing the shelf life of food products

Studies were carried out to develop eco-friendly Packaging material for the extended shelf-life of food products. The current study sought to improve the coated bioactive film's hydrophobicity and antimicrobial properties by preparing active packaging based on biodegradable Poly Lactic Acid (PLA) containing 1 wt% Nanocellulose (NC) and various loadings of essential oil-prepared nanocomposites. Nanocellulose (NC) from Maize Cob was used as filler in the synthesis of nanopolymers enriched with Thyme oil, Cinnamon oil, clove oil, and Rosemary oil. Characterization of nanopolymer-coated bags and their effect on enhancing the shelf-life of food products in different temperature conditions was also studied. The fabricated nanocomposite and nanocellulose were characterized using FTIR, SEM, XRD, Contact angle, TGA, and Tensile mechanical properties. The fabricated nanocomposite-coated paper cum bag shows good hydrophobic properties as well as antimicrobial and insecticidal properties. The results showed that adding essential oils and dispersing nanocellulose to the PLA matrix strengthened its mechanical qualities as well as its efficacy for biodegradation and antimicrobial properties. The current work provides extremely promising materials for future applications in food packaging applications using sustainable nanocomposite-based biodegradable and antimicrobial coated paper cum bags.

Investigation on mechanical behavior of engineered cementitious composites incorporating alkali‐resistant glass fiber and quarry dust

AbstractAt present, engineered cementitious composites (ECC) are rapidly replacing ordinary concrete in the building production due to its superior durability and mechanical qualities. Enormous researches have been done on ECC incorporating various fibers, industrial wastes, supplementary cementitious materials and super plasticizers. As far as fiber is concerned, poly vinyl alcohol fiber was widely explored. In this study, attempt has been made to involve alkali resistant glass fiber as a replacement for poly vinyl alcohol fiber. In addition, the high rate related with ECC as a result of the utilization of micro‐sized silica sand has restricted its extensive pertinences. Thus, this study recommends utilization of quarry dust to replace fine silica sand in the ECC at amounts ranging from 0% to 100% in order to establish a green, sustainable and cost‐effective ECC. The flowability and mechanical demeanor of the ECC mixtures in terms of the tensile, compressive and flexural properties were evaluated. It is arrived that 2% of volume fraction would be the optimum dosage by which better mechanical properties can be achieved. As a result of the present research findings, it is found that the quarry dust could be a better substitute for silica sand up to 75% without any compromise in compressive and flexural strengths. To attain higher tensile qualities, however, it might not be appropriate to replace more than 50% of the silica sand with quarry dust. Cost analysis of the ECC mixtures show that using quarry dust as aggregate is both cost‐effective and sustainable.

Effects of Glass Fiber on a Mechanical Properties of Concrete

The purpose of the study is to find out how adding glass fiber to concrete can improve its mechanical qualities. It assesses qualities including compressive strength, flexural strength, and strength and contrasts glass fiber-reinforced concrete (GFRC) with regular concrete. Tests on concrete samples with different glass fiber contents reveal that higher fiber content enhances ductility and flexural strength. Environmental pressures like chemical attacks and freeze-thaw cycles are not able to break down GFRC. Tests are enhanced by finite element analysis (FEA), which shows the distribution of stress and strain in the composite. In general, the research advances our knowledge of how GFRC may fortify concrete constructions, perhaps leading to the development of more robust building frameworks.

Enhanced mechanical qualities of sericin‐removed silk by direct feeding of silkworms with cellulose nanofiber

AbstractRecently, the modification of silkworm silk fibers (SFs) by adding fillers has been investigated. Previously, we have reported that SFs obtained from silkworms fed diets supplemented with 5 wt.% cellulose nanofiber (CNF) and whose surface was covered with sericin exhibited excellent tensile properties. On the other hand, to use SF in silk products, the sericin must be removed, and it is necessary to ensure that CNF‐enriched silkworm SFs with the sericin removed (i.e., fibroin) exhibit high tensile properties. Therefore, this study evaluated the tensile properties of sericin‐removed SF obtained from silkworms fed a CNF diet. The results showed that the average CNF with SF—near 7.5 wt.% exhibited high mechanical properties. Adding CNF to the silkworm diet did not affect their growth and cocoon yield. The analysis of the SF microstructure confirmed that CNF is a fibrous material on the surface of fibroin. Kelly‐Tyson's equation suggested that almost all of the CNF in fibroin contributed to the increased tensile strength.

The effect of canal curvature on cyclic fatigue resistance of rotary instruments using different irrigation materials (in vitro study)

Background The mechanical qualities of Ni-Ti is crucial because they give the files their flexibility and enable us to prepare curved and double-curved canals with more ease. It happens frequently for instruments to separate during canal preparation, and cyclic fatigue (metal fatigue) is a frequent cause. This study aimed to assess how irrigation affected the two rotary endodontic instruments’ cyclic fatigue resistance. Methods The Edge File and Fanta File rotary endodontic instrument groups were chosen. Each group (n = 42) was split into 3 subgroups (n = 14 each), one receiving NaOH, one Glycine, and one EDTA treatment. The number of cycles to failure (NCF) was determined after each subgroup underwent testing for cyclic fatigue resistance. Results The result appeared different significant between the two group and sub-group with the different materials that used with it with the length of fractures and time that recorded in each group. Conclusion NaOCl, glycine, and EDTA as chemical materials appeared to have considerably varied cycle fatigue resistance for various lengths of fractures and durations, according to the comparison between the two evaluated instruments.

Decomposing the inequalities in the catastrophic health expenditures on the hospitalization in India: empirical evidence from national sample survey data

IntroductionSustainable Development Goal (SDG) Target 3.8.2 entails financial protection against catastrophic health expenditure (CHE) by reducing out-of-pocket expenditure (OOPE) on healthcare. India is characterized by one of the highest OOPE on healthcare, in conjunction with the pervasive socio-economic disparities entrenched in the population. As a corollary, India has embarked on the trajectory of ensuring financial risk protection, particularly for the poor, with the launch of various flagship initiatives. Overall, the evidence on wealth-related inequities in the incidence of CHE in low- and middle-Income countries has been heterogenous. Thus, this study was conducted to estimate the income-related inequalities in the incidence of CHE on hospitalization and glean the individual contributions of wider socio-economic determinants in influencing these inequalities in India.MethodsThe study employed cross-sectional data from the nationally represented survey on morbidity and healthcare (75th round of National Sample Survey Organization) conducted during 2017–2018, which circumscribed a sample size of 1,13,823 households and 5,57,887 individuals. The inequalities and need-adjusted inequities in the incidence of CHE on hospitalization care were assessed via the Erreygers corrected concentration index. Need-standardized concentration indices were further used to unravel the inter- and intra-regional income-related inequities in the outcome of interest. The factors associated with the incidence of CHE were explored using multivariate logistic regression within the framework of Andersen’s model of behavioral health. Additionally, regression-based decomposition was performed to delineate the individual contributions of legitimate and illegitimate factors in the measured inequalities of CHE.ResultsOur findings revealed pervasive wealth-related inequalities in the CHE for hospitalization care in India, with a profound gap between the poorest and richest income quintiles. The negative value of the concentration index (EI: −0.19) indicated that the inequalities were significantly concentrated among the poor. Furthermore, the need-adjusted inequalities also demonstrated the pro-poor concentration (EI: −0.26), denoting the unfair systemic inequalities in the CHE, which are disadvantageous to the poor. Multivariate logistic results indicated that households with older adult, smaller size, vulnerable caste affiliation, poorest income quintile, no insurance cover, hospitalization in a private facility, longer stay duration in the hospital, and residence in the region at a lower level of epidemiological transition level were associated with increased likelihood of incurring CHE on hospitalization. The decomposition analysis unraveled that the contribution of non-need/illegitimate factors (127.1%) in driving the inequality was positive and relatively high vis-à-vis negative low contribution of need/legitimate factors (35.3%). However, most of the unfair inequalities were accounted for by socio-structural factors such as the size of the household and enabling factors such as income group and utilization pattern.ConclusionThe study underscored the skewed distribution of CHE as the poor were found to incur more CHE on hospitalization care despite the targeted programs by the government. Concomitantly, most of the inequality was driven by illegitimate factors amenable to policy change. Thus, policy interventions such as increasing the awareness, enrollment, and utilization of Publicly Financed Health Insurance schemes, strengthening the public hospitals to provide improved quality of specialized care and referral mechanisms, and increasing the overall budgetary share of healthcare to improve the institutional capacities are suggested.

The effect of gamma rays and stearic acid on calcium carbonate and its impact on the properties of epoxy-based composites

Abstract The purpose of this research is to produce composites of epoxy resin and calcium carbonate (EP/CaCO3) and investigate how treating the CaCO3 filler with stearic acid and gamma radiation affects the properties of the epoxy composites, enhancing their suitability for a range of applications. The CaCO3 powder was subjected to stearic acid treatment and later exposed to γ-radiation at various doses namely (10, 20 and 30 kGy), Different weight percentages of untreated and treated CaCO3 powder were added to epoxy resin (EP) to create EP/CaCO3 composites loaded with varying amounts of CaCO3 filler (5 %, 10 %, 20 %, 30 %, and 40 %). The influence of both stearic acid treatment and different doses of gamma radiation on CaCO3 was investigated. The composites were subjected to characterization of various properties including mechanical (splitting tensile strength, impact strength), thermal (TGA and dimensional thermal analysis) as well as morphological SEM examination. The analysis’ findings demonstrated that the stearic acid monolayer functions as a coupling agent in the EP matrix and can coat CaCO3 particles efficiently. The modification of CaCO3 by stearic acid and exposure to 30 kGy of gamma radiation shows a notable improvement in thermal stability and mechanical qualities for the epoxy composites loaded with various CaCO3 concentrations.

The Effect of Nano-Hydrated Lime on the Durability of Warm Mix Asphalt

Premature failure in asphalt concrete pavement has been the main concern for pavement construction companies and engineers in recent years because of the large rise in traffic volume and loads and the temperature extremes in the summer and winter. The use of modifiers in asphalt concrete mixtures has attracted much attention to increase the performance and lifespan of pavements. As nanotechnology developed, several researchers concentrated on how these materials can help increase pavement serviceability by minimizing rutting and moisture damage. This study evaluates the Hydrated Lime (HL) effect by two methods (wet and dry hydrated lime) on the durability of the warm mix asphalt. The first method, HL, has been supplemented to the asphalt binder with three ratios (0.5%, 1%, and 1.5%) by weight of asphalt (Wet HL). Then, the second method was added via the aggregate weight as a replacement filler using three percentages (1%, 2%, and 3%) (Dry HL). The mechanical qualities, including Marshall Mix design, moisture susceptibility, and permanent deformation, were evaluated through experimental tests. Results showed that the mechanical characteristics and the fineness of the HL particle sizes are positively correlated.            

Mechanical Properties Geopolymer Concrete Based on Fly Ash PLTU Tanjung Jati B Jepara As An Alternative Material

Geopolymer concrete is a new material and has very good prospects because it does not use cement, where the material uses environmentally friendly materials and is energy-efficient, because it can use industrial waste materials and manufacturing processes. Geopolymer concrete does not require too much energy, as does the process from making cement which requires at least temperatures up for 800°C. The aim of this study is to evaluate and examine the worth of geopolymer concrete’s mechanical qualities. Compression tests, split tests, and flexural strength tests on geopolymer concrete are all part of the battery of mechanical properties tests. The trial study of geopolymer concrete was used to inform the mix design employed in the production of the test specimens. Merapi sand fine aggregate, 10-20 mm coarse aggregate, PLTU Tanjung Jati B Jepara fly ash from coal waste, Na2SiO3, 8M NaOH activator, and 2% fly ash superplasticizer were employed in this research. Three 15/30 cylinders are used to test concrete’s compressive strength, three 15/30 cylinders are used to test concrete’s split tensile strength, and three 15x15x60 are used to test concrete’s flexural strength in this study. After only 28 days, testing could begin. Compressive strength was found to be 31.746 MPa, split tensile strength was 3.920 MPa, and flexural strength was found to be 4.833 MPa for geopolymer concrete.

Review on Investigating Soil Stabilized Mud Blocks with Combined C&D Waste

Buildings built by ancient civilizations like the Mesopotamians and Egyptians were made of clay and other materials, and the use of stabilized soil for construction dates to those times. On the other hand, the scientific underpinnings of soil stabilization were not established until the early 1900s. In comparison to conventional building materials, the use of stabilized soil-based construction materials, such as soil stabilized mud blocks, can offer several advantages, such as improved strength and durability, less of an adverse effect on the environment, and lower costs. The world is facing an issue that calls for the disposal of inorganic solid waste to be addressed right away. This solid waste that is produced when old buildings are demolished is frequently classified as industrial waste or C&D waste. In India alone, enormous amounts of waste are produced, very little of which is recycled. When modifying the properties of stabilized soil, this C&D waste can be used in place of soil or quarry sand. This work explores the use of a stabilizing agent in conjunction with combined C&D waste for soil sampling. The studies use combined C&D waste and soil stabilized mud blocks to test the hollow blocks' water absorption capacity and strength for various replacements. The materials needed for the study came from nearby structures that had been demolished. Using mortar, cylindrical samples for 32 different ratios of mixed construction and demolition waste with a 9% cement content were cast for various compositions. To determine whether the stabilized samples were suitable for use in construction, tests were conducted on their compressive strength and water absorption properties. Based on the least compressive values found in cylindrical samples, the C&D waste was used in ratios ranging from 0% to 100% in place of soil. Mud blocks stabilized by soil were poured and examined for durability, strength, and mechanical qualities. In this study, an effort was made to use C&D waste—that is, brick and concrete waste—in varying amounts to create cylindrical samples that could be used to create concrete and stabilized mud blocks. In order to create cylindrical samples, different ratios of brick waste, concrete waste, and brick-concrete waste were used for 23 mix proportions. Cylindrical samples were manufactured using a cement content of 9 and 12%. These samples' mechanical and physical characteristics, such as their compressive strength, water absorption capacity, and initial rate of absorption, were investigated.

Impact of Sole Layer Duple Substrates on GA-Based Optimised Graphene Antennas for THz Applications

The widespread use of graphene patch antennas is escalating as evidence of their applicability in areas like 6G communications and THz spectroscopy. Geometric uncertainty and fabrication issues while downsizing makes terahertz antenna design problematic. Graphene's electromagnetic and mechanical qualities make it ideal for miniaturizing antennas for Terahertz use. In the THz spectrum, a graphene antenna requires careful dielectric material selection since performance fall, especially efficiency. This paper compares dual band multi-layered genetic algorithm-based optimized antennas for the THz applications, especially spectroscopy and 6G utilizing sole layer duple substrates concept, i.e., two distinct substrates at the same level between the ground and patch. Different antennas are designed using various substrates like Rogers RO3010, RO3210, RT5880, RT5880LZ, TMM 13i, Taconic TLY-3, RF-10, Silicon, & Teflon. Two segments of four antennas are planned; one has silicon as a common substrate with four additional materials, and another has Teflon. The proposed antenna's performance is assessed in terms of bandwidth, beamwidth, directivity, efficiency, gain, radiation pattern, return loss, and VSWR. The results reveal that Silicon and Rogers RT5880 LZ substrates-based antenna perform better in a segment I, with bandwidth (GHz) of 150.1 and 156.9, directivity (dBi) of 5.93 and 4.23, efficiency (%) of 76.65 and 78.98, and gain (dB) of 4.97 and 3.3. While in segment II, Teflon and Taconic RF-10-based antenna perform better with features 158 and 198 bandwidth, 6.43 and 4.43 directivity, 74 and 83 efficiency, and 4.67 and 3.65 gain.

Isolation and characterization of novel bioplasticizers from rose (Rosa damascena Mill.) petals and its suitability investigation for poly (butylene adipate-co-terephthalate) biofilm applications.

The current growing environmental awareness has forced the use of biodegradable plasticizers, which are sustainable and abundant in plant resources. Rose petal plasticizers (RPP) act as an actual substitute for chemical plasticizers in this situation as they are biocompatible and biodegradable. Chemical procedures like amination, alkalization, and surface catalysis are used to extract the natural emollients from rose petals. XRD, FT-IR, and UV studies were used to understand the characteristics of the rose petal plasticizer. Based on the XRD data, the RPP's crystallinity size (CS) and crystallinity index (CI) values were determined to be 9.36nm and 23.87%, respectively. The surface morphology of the isolated plasticizer is investigated using SEM, EDAX analysis and AFM. RPP surface pores with rough surfaces are visible in SEM images, which make them appropriate for plasticizing novel bioplastics with superior mechanical qualities. The plasticizer's heat degradation behaviour is investigated using thermogravimetric and differential thermogram analysis curves. Following the characterization of the synthesised molecules, the plasticization effect was examined using a biodegradable polymer matrix called poly (butylene adipate-co-terephthalate) (PBAT). The reinforcement interface was also examined using scanning electron microscopy analysis. RPP-reinforced films demonstrated greater flexibility and superior surface compatibility at a 5% loading compared to PBAT-only films. Based on a number of reported features, RPP could be a great plasticizer to address future environmental problems.

A high-power ultrasonic transducer operated in MHz range by circular plate bending mode using a single parabolic reflector

This research developed a HF, high-power ultrasonic transducer. Operating at 1.54 MHz, the transducer generated plane waves through the excitation of the thickness mode of a piezoelectric ring. These waves are subsequently focused by a parabolic reflector, exciting the bending mode of a circular plate and yielding substantial mechanical output at the center. Under a driving voltage of 48 Vpp, the transducer achieved a saturation velocity of 11.7 mpp/s. The mechanical quality factor ( Qm ) of the resonant mode is calculated using the half-power bandwidth method, resulting in a value of approximately 1250. The proposed transducer exhibits outstanding performance and holds promising applications in the fields of biology, medicine, and sonochemistry.

A wastes-based hierarchically structured cellulose membrane: adsorption performance and adsorption mechanism

It was imperative to expeditiously investigate novel avenues for the valorization of agricultural waste biomass crop straws. The straws represented promising substrates to design eco-friendly adsorbents for the effective treatment of complex dyeing wastewater owing to their widespread availability, low cost, easy production, and environmental friendliness. Despite the advantages, developing adsorbents with versatile uses, antibacterial properties, and strong mechanical qualities remained a challenge. Herein, a sustainable waste treatment strategy is put forward by developing multifunctional adsorbents derived from agricultural waste. The adsorbents are designed to synchronously adsorb the typical contaminants such as organic molecule (methylene blue, MB) and heavy metal ions (cadmium ion, Cd2+) in dyeing wastewater. Through the assembly of cellulose fibers, multiscale cellulose membrane (MCM) substrates with enhanced two-dimensional (2D) structure were simply fabricated from biomass crop straws. Coating functional copper phosphate (CP) nanoflakes on the MCM substrate effectively constructed the hierarchical structure to achieve the synchronous adsorption. The synergistic effects of electrostatic attraction, hydrogen bonding and coordination greatly prompted the adsorption process. Furthermore, the multifunctional adsorbents were imparted with satisfactory antibacterial properties, thereby expected to solve the problem of membrane fouling in wastewater. Hierarchically structured copper phosphate @ cellulose antibacterial adsorbents (CP@MCM) exhibit huge application potential in the resource utilization of agricultural waste and effective treatments for dyeing wastewater.

Recycling and reusing potential of disposable low-density polyethylene plastic waste for flexible paver tile construction for outdoor application

Plastic waste disposal has escalated into a serious global concern due to the non-biodegradable nature of plastics, which are composed of high-molecular-mass organic polymers along with other ingredients. Therefore, this study focuses on reusing and recycling LDPE plastic waste as a binding agent in paver tile production. This aligns with global sustainability goals by promoting resource efficiency and reducing waste generation. The investigation aims to address the environmental impact of plastic waste by finding sustainable solutions for its management. This includes exploring the feasibility and viability of using LDPE plastic waste in paver tile production as a means of recycling and reusing locally collected waste. The LDPE waste plastic collection, identification, milling, and melting at 170 °C. Subsequently, the sampled sand, sieved to a size of ≤0.75 mm, was blended with molten plastic in a specified proportion and then molded to create paving tiles using a hydraulic press machine. The researchers utilized response surface methodology (RSM) combined with Box-Benken designs (BBD) to optimize three key experimental parameters (plastic-to-sand ratio: 10 %, 25 %, 40 %; time: 2, 5, 8 min, pressure: 1, 3, 5 MPa) influencing mechanical properties of paver tiles, including water absorption (WA), flexural strength (FS), and compressive strength (CS). The result revealed that the optimal combination of 25 % waste plastic, 5 min, and 3 MPa of pressure resulted in a maximum flexural strength (FS) of 3.689 MPa and compressive strength (CS) of 4.141 MPa, with an average water absorption (WA) of 0.322 %. Therefore, the mechanical properties of the developed tiles met the desired standard. In conclusion, the mechanical qualities of the tiles were promising, indicating that reusing waste LDPE plastic to create paver tiles presents an appealing option for plastic waste disposal. The composite paver tiles exhibited promising attributes for outdoor applications, such as park pavement and outdoor public spaces, owing to their favorable mechanical properties and low water absorption.

Modified Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 ceramics with high d33，large Qm and high Tc

The development of piezoelectric ceramics with large piezoelectric coefficient (d33), high Curie temperature (Tc) and high mechanical quality factor (Qm) is still a key challenge for practical application for high-power device. Herein, a series of Sm3+ and Mn2+ ions co-doped 0.15Pb(Mg1/3Nb2/3)O3-(0.85-x)PbZrO3-xPbTiO3 ceramics were prepared by the solid-state sintering method. The optimum piezoelectric properties were achieved at x = 0.435mol% with a large d33 ~ 450 pC/N and a high Qm ~ 1968 near the morphotropic phase boundary (MPB), and with high Tc ~ 296 °C. The origin of this excellent piezoelectric properties was explained by the phase structure, piezoelectric and dielectric analysis. The composition near MPB region and the appearance of defect dipoles leaded to final excellent piezoelectric properties, and made a harmonization between d33, Tc and Qm. This work demonstrated a rational strategy to obtain large d33, high Tc and high Qm for high-power piezoceramics.

Precise evaluation of the material constants of [011]-poled mangan-doped 0.32Pb(In1/2Nb1/2)O3-0.39Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 single crystals

Recently, there has been a surge of interest in [011]-poled Mn: PIN-PMN-PT piezoelectric single crystals for high-power transducers. These crystals boast impressive electromechanical coupling coefficients, piezoelectric constants in the transverse mode, and excellent heat resistance due to their high mechanical quality factor. To effectively design transducers using these crystals, understanding their material constants is crucial. Our study focused on determining these constants by employing the resonance method. We created eleven different resonators, analyzed their impedance spectra, and derived seventeen elastic compliance, piezoelectric, and dielectric constants. The precision of the obtained material constants was enhanced by minimizing the difference between the impedance spectra found through finite element analyses and actual measurements of each resonator. The accuracy of these derived constants was validated by comparing the impedance spectra obtained from analysis with those measured experimentally. This novel approach demonstrated a capability to derive more precise material constants than prior studies. These refined material constants hold the potential to enable more precise and effective design of acoustic transducers constructed from the single crystals.

Exploring the Development of Natural Biopolymer (Chitosan)-Based Proton Exchange Membranes for Fuel Cells: A Review

Fuel cells use proton exchange membranes (PEMs) to transform a chemical energy into electricity. Hydrogen is the most common fuel used in fuel cells. PEMs are selective barriers that only let protons pass through, obstructing gases and other species like electrons. A polymer electrolyte is a substance containing both positively and negatively charged ions and generally used to create PEMs. Nafion is one perfluorinated sulfonic acid membrane, which is the most popular polymer used in PEMs. This substance exhibits great chemical stability, strong mechanical qualities, and high proton conductivity. PEMs have a number of issues, one of which is their propensity to degrade with time, especially at high temperatures and in the presence of pollutants. In order to address this, researchers are looking into new materials and methods to enhance the performance and durability of PEMs, such as adding nanomaterials, coming up with new polymer architectures, and establishing cutting-edge manufacturing techniques. Biopolymer based PEMs such as chitosan have demonstrated great potential to be used in PEMs. They are environmentally friendly and economical. However, the key challenge in using chitosan in fuel cells is their relatively poor ionic conductivity. Researchers have developed various strategies to improve their conductivity, such as doping with conductive materials or incorporating functional groups that enhance charge transfer. Overall, chitosan has shown promise as renewable and sustainable materials for use in fuel cells. The review summarizes the current development and evolution of chitosan-based PEMs.

Enhanced high-power behaviors of Mn-doped Pb (In1/2Nb1/2) O3-Pb(Mg1/3Nb2/3) O3-PbTiO3 piezoelectric crystals through combining direct and alternating current polarization

Elevating both the mechanical quality factor and piezoelectric properties is pivotal for enhancing the efficiency of high-power piezoelectric devices. Mn-doped Pb (In1/2Nb1/2) O3-Pb(Mg1/3Nb2/3) O3-PbTiO3 (Mn: PIN-PMN-PT) single crystals have previously exhibited a notable mechanical quality factor, yet encountered a substantial decline in piezoelectric coefficient. In pursuit of the concurrent optimization of these parameters, we explored the co-enhancement of mechanical quality factor and piezoelectric coefficient in [001]-oriented Mn: PIN-PMN-PT single crystals by employing a synergistic approach (DCP-ACP) involving direct-current poling (DCP) and alternating-current poling (ACP). Our investigation reveals a remarkable improvement, with the piezoelectric coefficient and mechanical quality factor experiencing a notable surge of 53% and 118%, respectively, compared to the outcomes achieved with DCP alone. Compared to the ACP method, the piezoelectric coefficient and the mechanical quality factor were improved more than 7% and 18%, respectively. Moreover, the coercive field and remnant polarization of the single crystals witnessed a substantial upswing post DCP-ACP. The results are attributed to the elimination of the 71° domain walls, as observed through polarized light microscopy. Here we demonstrate Mn: PIN-PMN-PT single crystals are expected to has high mechanical quality factor and strong piezoelectric constants through DCP-ACP, thus suggesting a new route to high performance ferroelectrics.