Enhanced Thermal Stability, Mechanical Properties and Structural Integrity of MWCNT Filled Bamboo/Kenaf Hybrid Polymer Nanocomposites

Recently, there has been an inclination towards natural fibre reinforced polymer composites owing to their merits such as environmental friendliness, light weight and excellent strength. In the present study, six laminates were fabricated consisting of natural fibres such as Kenaf fibre (Hibiscus cannabinus L.) and Bamboo fibre, together with multi-walled carbon nanotubes (MWCNTs) as reinforcing fillers in the epoxy matrix. Mechanical testing revealed that hybridization of natural fibres was capable of yielding composites with enhanced tensile properties. Additionally, impact testing showed a maximum improvement of ≈80.6% with the inclusion of MWCNTs as nanofiller in the composites with very high energy absorption characteristics, which were attributed to the high specific energy absorption of carbon nanotubes. The viscoelastic behaviour of hybridised composites reinforced with MWCNTs also showed promising results with a significant improvement in the glass transition temperature (Tg) and 41% improvement in storage modulus. It is worth noting that treatment of the fibres in NaOH solution prior to composite fabrication was effective in improving the interfacial bonding with the epoxy matrix, which, in turn, resulted in improved mechanical properties.

Investigation of Weight Fraction and Alkaline Treatment on Catechu Linnaeus/Hibiscus cannabinus/Sansevieria Ehrenbergii Plant Fibers-Reinforced Epoxy Hybrid Composites

The aim of the present work is to develop novel hybrid composites using areca, kenaf, and snake grass fibers as reinforcement and epoxy as the matrix. The areca, kenaf, and snake grass fibers were extracted from Catechu Linnaeus, Hibiscus cannabinus, and Sansevieria Ehrenbergii plants, respectively, and treated with 5% NaOH to improve the interfacial adhesion between the hydrophilic fiber and the hydrophobic matrix. Hybrid composites were developed by the compression molding technique and formulated based on the weight fraction of fibers. Tensile, flexural, and impact strength and hardness samples were prepared as per ASTM D 3039, ASTM D 790, ASTM D 256, and ASTM D 2240, respectively. The effects of alkaline treatment on developed hybrid composites were investigated. The developed hybrid composites with 20% wt. snake grass and 10% wt. areca fiber present interesting mechanical properties with a tensile strength of 58 MPa, flexural strength of 124 MPa, impact strength of 5.24 kJ/m2, and hardness of 88. The results indicate that maximum mechanical properties were obtained for alkaline-treated fiber composites with 20% wt. snake grass fiber compared to untreated fiber composites owing to better adhesion between the treated fiber and the matrix. The effect of alkaline treatment was analyzed by Fourier transform infrared. The fractured surfaces of tested samples were analyzed by scanning electron microscopy.

Behavioral Responses of a Generalist Pest, Spilosoma Obliqua Walker, Towards the Leaf Surface Wax Chemicals of Three Types of Jute Crop and Implications in Pest Management

Behavioral responses of a generalist pest, Spilosoma obliqua Walker (Lepidoptera: Arctiidae), towards the leaf surface wax chemicals of three types of jute crops (white jute, Corchorus capsularis, tossa jute, C. olitorious,, and mesta jute or kenaf, Hibiscus cannabinus [Malvaceae]) and their implications in pest management was studied under laboratory conditions. The GC-MS and GC-FID analyses of the jute leaf epicuticular waxes indicated the presence of 27 n-alkanes, having chain lengths from n-C14 to n-C36 and 14 free fatty acids (FFAs) having chain lengths from C12:0 to C22:0. Among the identified n-alkanes and FFAs of selected jute cultivars n-C34 (144.397±6.971 µg leaf−1) and C16:1 (37.034±0.848 µg leaf−1) of tossa jute leaves were most abundant. The host preference (white jute> tossa jute > mesta jute) of S. obliqua was evaluated simultaneously by olfactory, visual, and tactile recognition, as valid for other lepidopteran species. For olfaction [females], oviposition [gravid females], and feeding [larvae]) in S. obliqua, the most stimulating combined-synthetic-mixture of epicuticular wax components was represented by 4 n-alkanes (n-C16, n-C18, n-C20, n-C22) and 5 FFAs (C16:1, C16:0, C18:0, C20:0, C22:0) in mixture at leaf equivalent (µg leaf−1) amounts (195.209±2.950 µg, 119.777±1.857 µg, and 50.567±3.508 µg, respectively) in white jute, tossa jute, and mesta jute, respectively. Thus, the present study suggests that the synthetic blends of 4 n-alkanes and 5 FFAs of respective jute crops can be used as lures to develop baited trap as a part of integrated pest management (IPM) of S. obliqua for sustainable jute cultivation.

Ruta graveolens, Pelargonium graveolens E Hibiscus cannabinus COMO INIBIDORES NATURAIS DO CRESCIMENTO DE Candida albicans

Candidiasis is an infection caused by fungi of the genus Candida, Candida albicans being the species that most causes the disease in Brazil. The Fluconazole is the conventional medicine used as a treatment of these infections; however, it causes many adverse reactions in the patient and its continued use can induce the resistance of the pathogen. The medicinal plants can be very effective as an alternative treatment of diseases and have been used in folk medicine for years. In this study, it was evaluated the antifungal activity of extracts of Ruta graveolens, Pelargonium graveolens and Hibiscus cannabinus against the fungal development of Candida albicans, comparing the efficiency of these extracts to Fluconazole. The extracts were prepared in the concentration of 1g of the plant for each 5 mL of alcohol 70%. The data were obtained using the agar diffusion method. The minimum inhibitory concentration test (MIC) was performed, and showed that R. graveolens was able of inhibiting 100% of the pathogen when using 100 mg.ml-1 concentration. From the results obtained, it was possible to conclude that R. graveolens was the most effective extract when compared to Fluconazole, suggesting that this extract can be used as an alternative to conventional treatment to improve the efficiency of current treatments. The extracts of P. graveolens and H. cannabinus also presented antifungal activity but in smaller proportion than Fluconazole. The data from this study suggests that R. graveolens extract can be tested in future in vivo studies with the objective of proposing its use in alternative or simultaneous treatment of the synthetic drug used.

The Transcription Factor HcERF4 Confers Salt and Drought Tolerance in Kenaf (Hibiscus Cannabinus L.)

Ethylene response factors (ERF) are members of the APETALA2/ERF transcription factor family, and they play an important role in plant growth, development, and response to various environmental stresses. In the present study, an ERF transcription factor HcERF4 was isolated and characterized from kenaf. The protein encoded by the HcERF4 has 233 amino acid residues with a theoretical isoelectric point of 8.89 and a predicted molecular weight of 25.53 kDa. HcERF4 had an over than 86.97% identity to HsERF4(XP_039019980.1), and shared a closest phylogenetic relationship with Hibiscus syriacus. Subcellular localization analysis shows that HcERF4 is located in the nucleus. Transactivation assays in yeast demonstrated that HcERF4 functions as a transcriptional activator. The expression of HcERF4 was enriched in leaf and root, and can be induced by salt or drought treatments in kenaf. The VIGS-silenced HcERF4 plant showed significantly reduced plant height, stem diameter, fresh weight, and relative water content (RWC) compared with wild type plants under salt or drought stress condition; In addition, the contents of MDA, O2−, H2O2, and free proline is significantly increased, and the activities of SOD and CAT are significantly reduced. The DAB/NBT staining results showed that the H2O2 and O2− contents in HcERF4-silenced plants were consistent with the determination. Based on these results, it is proposed that HcERF4 plays an important role in regulating salt and drought stress in kenaf.

Solution of sowing methods and seeding rates for the intraductive kenaf (Hibiscus cannabinus) seeds

This research was prepared on the basis of an expedition conducted by the Department of Applied Ecology of National University of Uzbekistan in four territories adjacent to the Aral Sea: Karakalpakstan, Bukhara, Khorezm, and Navoi provinces, in particular in 20 cities of Uzbekistan. The expedition was carried out within the framework of the project “Program for adaptation to climate change in the Aral Sea Basin and mitigation of its consequences”, under the auspices and assistance of the International Development Association. Also, the Agency for the Structural Transformation of Agricultural Enterprises and the Consulting Company Intellect management took an active part in the project. The aim of the study was to assess climate change, understanding the impact of dangerous consequences, measures to adapt to climate change in Uzbekistan. To find possible objective and scientific approaches to the application in a broad sense of methods for confrontation in all areas of agricultural activity was also a potential objective of this paper. In addition, within the framework of this program, in 20 cities, local inhabitants were familiarized with the results of this study by conducting lectures, trainings and seminars for representatives of production, farms, workers of agricultural enterprises, scientific researchers, undergraduates, bachelors of higher education in the project area.

Synthesis of Ce/MgO Catalysts for Direct Oxidation of Hibiscus cannabinus Stalks to Vanillin

One possible method of producing vanillin from biomass is through controlled oxidation of lignin. Direct oxidation of kenaf stalks was chosen without having to separate the cellulose and hemicellulose components from the lignocellulosic biomass. This makes the process greener, as well as saving time. In this paper, Ce/MgO catalysts were developed for oxidation of kenaf stalks and kenaf lignin under microwave irradiation. The catalysts were characterized for their physicochemical properties using XRD and N2 adsorption–desorption isotherms. The synthesized MgO showed the presence of diffraction peaks assigned to cubic MgO while the 30Ce/MgO catalysts showed the presence of cubic fluorite of CeO2. N2 adsorption–desorption isotherms showed that all catalysts possess Type III isotherm according to IUPAC classification, indicating a nonporous structure. All catalysts were tested for direct oxidation of kenaf stalks under 300 W of microwave irradiation using H2O2 as the oxidizing agent at pH 11.5 and temperatures between 160 and 180 °C for 10–30 min with 5–15% catalyst loading. The highest vanillin yields of 3.70% and 2.90% for extracted lignin and direct biomass oxidation were achieved using 30Ce/MgO-48. In comparison, 7.80% and 4.45% were obtained using 2N of NaOH homogeneous catalyst for extracted lignin and direct biomass, respectively, at 170 °C for 20 min. The reusability test shows that 30Ce/MgO can be used up to three cycles without significant loss in catalytic activity. Other compounds detected were 4-vinylguaiacol, syringol and syringaldehyde.

Soil Conservation Effects and Economic Benefit Of Different Crops Cultivated on Gentle Slopes In The South Mining Area, China

The runoff and sand production of two fibre crops, Hibiscus cannabinus L. (Kenaf) and Boehmeria nivea L. (Ramie), under natural rainfall conditions in natural gentle sloping (less than 10°) farmlands in a in mining area were studied. Abelmoschus esculentus L. Moench (Okra) and Zea mays L. (Maize) plants were used as the control. The results showed the rank of soil erosion moduli and average runoff coefficients among tested plant species were: okra plot > maize plot (CK) > kenaf plot > ramie plot. Economic benefits were harvested from different crop treatments, with the maximum of 25,157 CNY/ha for kenaf,19,440 CNY/ha for ramie, 16,858.6 CNY/ha for okra, and 18,332 CNY/ha for corn (CK) treatment. Results suggest that planting kenaf and ramie on gentle slopes in eastern Hunan is beneficial to water and soil conservation and can effectively prevent soil erosion. Bangladesh J. Bot. 50(3): 755-761, 2021 (September) Special