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The properties of organic fibre-based hybrid materials are influenced by a variety of factors and even minor changes in these variables can outcome in substantial discrepancies in strength. In this regard, the current study aims to optimise various influencing parameters such as weight percentage, alkaline treatment concentration, and fabrication parameters (compression moulding pressure, and temperature), with the goal of enhancing the overall strength of the composite. Calotropis gigantea-stem and Prosopis juliflora-bark fibres were used in varying weight percentages to create epoxy-based hybrid composites. After fabrication the mechanical characterisation like tensile, flexural, and impact properties of the composites were tested. Taguchi experimental design was applied, and the results were analysed using a hybrid Taguchi-grey relational investigation method. It was observed that a combination of 20 wt.% Calotropis gigantea/20 wt.% Prosopis juliflora/6 % NaOH pretreatment/100 °C temperature with 14 MPa pressure and had the most desirable mechanical properties in the fabricated composites. Calotropis gigantea ranks first in enhancing the composite strength, followed by Prosopis Juliflora, NaOH pretreatment%, compression moulding temperature and pressure. This work highlights the significant role of Calotropis gigantea and Prosopis Juliflora fibres in enhancing composite strength and provides valuable insights for future research in the field of hybrid composite development.

Natural fibre–polymer composites are widely used because they are economical and ecologically beneficial in a variety of applications. In order to improve its performance, this study focuses on examining the mechanical characteristics of an epoxy composite material that has been reinforced with banana fibre mats that have undergone NaOH treatment. Additionally, using various configurations both with and without eggshell powder (ESP), the compression moulding method was used to fabricate and investigate the impact of ESP on these mechanical qualities. The results showed that the composite with 25 weight percent banana fibre and 2.5 weight percent ESP had the maximum tensile strength (31.21 MPa), bending strength (33.69 MPa), and impact strength (2.84 kJ/m2). Strong interfacial adhesion between the banana and eggshell components was discovered via the microscopic examination of shattered surfaces. Notably, compared to untreated banana composites, the alkaline-treated banana materials showed fewer occurrences of pull-outs and fractures, leading to noticeably better mechanical performance.

The characteristics of natural fiber reinforced composites such as light weight, non-abrasive, nonflammable, nontoxic, low cost and biodegradable have grabbed the attention of current researchers in the area of composites. The objective of this study is to examine the interlaminar shear strength of the polyester based wood and woven jute hybrid composite. To accomplish this objective, the following parameters such as (i) wood density, (ii) wood weight ratio, (iii) woven jute type, (iv) number of jute layers, (v) cryogenic treatment duration and (vi) alkaline treatment duration, each at three different levels were picked and optimized using the Taguchi method. The fibers were pretreated with 5% of NaOH solution for different length of time to reduce the moisture absorption. The L27 orthogonal array was selected for the chosen parameters and the required composite materials were fabricated using hand lay-up techniques. The fabricated composites were then subjected to cryogenic treatment by immersing in liquid nitrogen at 77 K for different period of time. The interlaminar shear strength of the fabricated hybrid composites was done according to ASTM standard. The morphological features and degree of dispersions of fibers into the matrix of the fabricated hybrid composites were further studied and discussed.

Abstract This investigation is carried out to understand the effects of water absorption on the mechanical properties of hybrid phenol formaldehyde (PF) composite fabricated with Areca Fine Fibres (AFFs) and Calotropis Gigantea Fibre (CGF). Hybrid CGF/AFF/PF composites were manufactured using the hand layup technique at varying weight percentages of fibre reinforcement (25, 35 and 45%). Hybrid composite having 35 wt.% showed better mechanical properties (tensile strength ca. 59 MPa, flexural strength ca. 73 MPa and impact strength 1.43 kJ/m2) under wet and dry conditions as compared to the other hybrid composites. In general, the inclusion of the fibres enhanced the mechanical properties of neat PF. Increase in the fibre content increased the water absorption, however, after 120 h of immersion, all the composites attained an equilibrium state.

This study looks at how incorporating nanofiller into sisal/flax-fibre-reinforced epoxy-based hybrid composites affects their mechanical and water absorption properties. The green Al2O3 NPs are generated from neem leaves in a proportion of leaf extract to an acceptable aluminium nitrate combination. Both natural fibres were treated with different proportions of NaOH to eliminate moisture absorption. The following parameters were chosen as essential to achieving the objectives mentioned above: (i) 0, 5, 10, and 15% natural fibre concentrations; (ii) 0, 2, 4, and 6% aluminium powder concentrations; and (iii) 0, 1, 3, and 5% NaOH concentrations. Compression moulding was used to create the hybrid nanocomposites and ASTM standards were used for mechanical testing such as tension, bending, and impact. The findings reveal that combining sisal/flax fibre composites with nanofiller improved the mechanical features of the nanocomposite. The sisal and flax fibre hybridised successfully, with 10% fibres and 4% aluminium filler. The water absorption of the hybrids rose as the fibre weight % increased, and during the next 60 h, all of the specimens achieved equilibrium. The failed samples were examined using scanning electron Microscopic (SEM) images better to understand the composite’s failure in the mechanical experimentations. Al2O3 NPs were confirmed through XRD, UV spectroscope and HPLC analysis. According to the HPLC results, the leaf’s overall concentrations of flavonoids (gallocatechin, carnosic acid, and camellia) are determined to be 0.250 mg/g, 0.264 mg/g, and 0.552 mg/g, respectively. The catechin concentration is higher than the phenolic and caffeic acid levels, which could have resulted in a faster rate of reduction among many of the varying configurations, 4 wt.% nano Al2O3 particle, 10 wt.% flax and sisal fibres, as well as 4 h of NaOH with a 5 wt.% concentration, producing the maximum mechanical properties (59.94 MPa tension, 149.52 Mpa bending, and 37.9 KJ/m2 impact resistance). According to the results, it can be concluded that botanical nutrients may be used effectively in the manufacturing of nanomaterials, which might be used in various therapeutic and nanoscale applications.

The present study is aimed at investigating the effect of hybridisation on Kevlar/E-Glass based epoxy composite laminate structures. Composites with 3 mm thickness and 16 layers of fibre (14 layers of E-glass centred and 2 outer layers of Kevlar) were fabricated using compression moulding technique. The fibre orientation of the Kevlar layers had 3 variations (0, 45 and 60°), whereas the E-glass fibre layers were maintained at 0° orientation. Tensile, flexural, impact (Charpy and Izod), interlaminar shear strength and ballistic impact tests were conducted. The ballistic test was performed using a gas gun with spherical hard body projectiles at the projectile velocity of 170 m/s. The pre- and post-impact velocities of the projectiles were measured using a high-speed camera. The energy absorbed by the composite laminates was further reported during the ballistic test, and a computerised tomographic scan was used to analyse the impact damage. The composites with 45° fibre orientation of Kevlar fibres showed better tensile strength, flexural strength, Charpy impact strength, and energy absorption. The energy absorbed by the composites with 45° fibre orientation was 58.68 J, which was 14% and 22% higher than the 0° and 60° oriented composites.

Natural fibre-based composites are replacing traditional materials in a wide range of structural applications that are used in different environments. Natural fibres suffer from thermal shocks, which affects the use of these composites in cold environment. Considering these, a goal was set in the present research to investigate the impact of cryogenic conditions on natural fibre composites. Composites were developed using polyester as matrix and jute-fibre and waste Teak saw-dust as reinforcement and filler, respectively. The effects of six parameters, viz., density of saw-dust, weight ratio of saw-dust, grade of woven-jute, number of jute layers, duration of cryogenic treatment of composite and duration of alkaline treatment of fibres on the mechanical properties of the composite was evaluated with an objective to maximise hardness, tensile, impact and flexural strengths. Taguchi method was used to design the experiments and response-surface methodology was used to model, predict and plot interactive surface plots. Results indicated that the duration of cryogenic treatment had a significant effect on mechanical properties, which was better only up to 60 min. The models were found to be statistically significant. The study concluded that saw-dust of density 300 kg/m3 used as a filler with a weight ratio of 13 wt.% and a reinforcement of a single layer of woven-jute-fibre mat of grade 250 gsm subjected to alkaline treatment for 4 h in a composite that has undergone 45 min of cryogenic treatment presented an improvement of 64% in impact strength, ca. 21% in flexural strength, ca. 158% in tensile strength and ca. 28% in hardness.

The objective of this study was to explore the association between serum uric acid (SUA) levels and cardiovascular risk factors in the Indian population. This was a cross-sectional, population-based study. The study enrolled adults aged 20 years and above residing in rural, sub-urban, and urban. All participants completed a detailed questionnaire, underwent anthropometric measurements, and had blood samples collected. Participants were divided into three tertiles based on their SUA concentrations. A total of 2976 participants were included in this study, with 865 from rural, 1030 from sub-urban, and 1081 from urban populations. The mean values of cardiovascular risk factors were significantly higher in tertile 3 (p < 0.001) as compared to the other tertiles. However, we observed a negative trend between the increase of SUA and SUA/Scr ratio and HbA1c levels (Pearson correlation r = −0.068; p < 0.001 and r = −0.140; p < 0.001, respectively). The healthy and prediabetic groups did not show any significant change in HbA1c with increasing SUA levels, while an inverse trend was observed in diabetics. In the diabetic population, both men and women showed an inverse trend between increasing SUA levels and HbA1c in both known and newly diagnosed diabetes (p < 0.001). The study found a positive association between SUA levels and cardiovascular risk factors. However, HbA1c was inversely correlated with increasing SUA tertiles in both known and newly diagnosed diabetes, as compared to the general population. Additionally, both men and women with diabetes consistently showed an inverse relationship between increasing SUA/SCr ratio and HbA1c levels. • HbA1c was found to be inversely correlated with increasing SUA tertiles. • No significant HbA1c change observed with increasing SUA levels in healthy and prediabetic groups. • Diabetic men and women showed inverse association between SUA/SCr ratio and HbA1c. • Multivariate analysis found significant positive correlation between SUA and metabolic risk factors. [ABSTRACT FROM AUTHOR]

Aims: South Asia has emerged rapidly as an epicentre of non‐communicable diseases (NCDs) specifically diabetes and cardiovascular diseases. The prevalence rate, risk factors and aetiology of NCDs in different socio‐demographic settings are not clearly understood. This study was performed to assess the prevalence of diabetes and atherosclerosis and their risk factors in urban, sub‐urban and rural communities of South India. Methods: Three communities [Nallampatti (rural), Thadagam (sub‐urban) and Kalapatti (urban)] in South India were selected for participation in the KMCH‐NCD Studies. Study volunteers were administered a detailed questionnaire, underwent anthropometric measurements, clinical measurements including blood pressure, glycated haemoglobin (HbA1c), non‐fasting lipid profile and serum creatinine. Carotid intima‐media thickness was measured using B‐mode ultrasound. Multiple logistic regression analyses were performed to understand the association of risk factors with diabetes and atherosclerosis. Results: A total of 2976 native participants, ≥20 years of age were screened. The prevalence of diabetes was 16%, 26% and 23% respectively in the rural, sub‐urban and urban study populations. Association of obesity with diabetes was observed in only urban population while hypertension and dyslipidaemia showed association in both urban and semi‐urban populations. Association of diabetes with atherosclerosis was observed in urban and semi‐urban populations. Hypertension in semi‐urban and obesity and dyslipidaemia in urban population showed association with atherosclerosis. Conclusions: Diabetes and atherosclerosis burden reported in the three different communities were higher than previous reports, especially in rural and sub‐urban regions. No traditional risk factor is identified to be associated with prevalence of diabetes and atherosclerosis in rural population. These findings suggest an urgent need for investigation into the role of non‐traditional risk factors like environmental or occupational exposures may help to better understand the aetiology of diseases in non‐urbanized communities. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to describe the distribution and comparison of carotid intima thickness in two completely different demographics in South India. Materials and Methods: Data were obtained from 865 participants in rural Nallampatti and 1081 participants from urban Kalapatti in the state of Tamil Nadu. Local ethics committee approval and written and informed consent were obtained from all participants. Carotid intima thickness was measured on all participants using high-resolution B-mode ultrasound. Atherosclerosis was defined as a carotid intima-media thickness of ≥1 mm. Results: The prevalence of atherosclerosis was 10.3% in rural Nallampatti compared to 7.8% in urban Kalapatti. On binary logistic regression analysis, diabetes and hypertension were associated with atherosclerosis in rural areas, but this significance disappeared after adjustment for confounding factors. In urban areas, diabetes appeared to be significantly associated with atherosclerosis even after adjustment for confounding factors. Conclusion: Our data suggest a surprisingly increased prevalence of atherosclerosis in a rural farming population even though traditional risk factors for atherosclerosis such as diabetes and hypertension did not show a significant association after adjustment for confounding factors. If confirmed, this provides a rationale to do large-scale studies to explore the role of nontraditional risk factors in rural India that could have an impact on atherosclerosis and cardiovascular disease. [ABSTRACT FROM AUTHOR]

Background: India is facing triple epidemic of Non communicable diseases (NCDs) including high body mass index (BMI), high blood pressure and high blood glucose, contributing to more than half of deaths of all mortality, however, information in different demographics is limited, especially, in India. The aim of the study is to compare the prevalence of overweight, obesity, hypertension, and diabetes, along with the occurrence of multi-morbidity, across gender-specific populations in rural, suburban, and urban regions of India., Methods: This was a cross-sectional, population-based study including adults aged 20 and above in rural, suburban, and urban areas near Coimbatore, India. All participants were interviewed using a detailed questionnaire and had their anthropometric measurements, including height, weight, blood pressure, and blood samples collected. Gender specific and location specific prevalence of overweight, obesity, hypertension, diabetes, and multimorbidity were assessed., Results: This study included 2976 individuals, of which 865 were from rural areas, 1030 from sub-urban areas, and 1081 from metropolitan areas. The mean systolic and diastolic blood pressure were higher in rural participants than in sub-urban and urban participants, despite the fact that the prevalence of hypertension was higher in sub-urban (47.1%) than in rural (36.4%) and urban (39.7%, p < 0.001). In sub-group analysis, sub-urban areas had a greater prevalence of hypertension in both men and women (53.5% and 41.7%, p < 0.001) than rural areas (41.9% and 31.3%, p = 0.001) or urban areas (45.9% and 35.5%, p < 0.001). Compared to rural (16.1%) and urban (23%), sub-urban areas had a greater prevalence of diabetes (25.8%, p < 0.001). Urban residents (47.5%) had higher rates of overweight and obesity than rural (31.4%) and sub-urban (34.1%, p < 0.001) residents. The association between diabetes and hypertension was present in the unadjusted model and persisted even after age and BMI adjustments. Though not in men, higher levels of education were associated to a higher prevalence of diabetes in women. Diabetes was associated to being overweight or obese in women, however this association was significantly reduced once BMI was taken into account. The overall multimorbidity was 3.8%, however, women had a higher overlapping prevalence (2.8%) compared to men (1%, p < 0.001)., Conclusions: Diabetes and hypertension were prevalent comorbidities across all demographics, with higher rates in suburban and urban areas. Women exhibited higher rates of multimorbidity than men, regardless of the demographic area., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)