Search

This study investigates the thermal performance of an evacuated U-tube solar collector (ETSC) using different tube geometrical configurations. The effect of tube geometry on the overall collector efficiency is numerically analyzed and compared with experimental results. Three different ETSC configurations made of copper viz., Model 1 (M1) having one inlet and two outlets, Model 2 (M2) having one inlet and three outlets, and Model 3 (M3) having one inlet and four outlets are considered. An overall rise in temperature of heat transfer fluid at the outlets for each model is predicted and compared with a conventional U-tube (CT) for different mass flowrates and solar insolations to evaluate the collector performance. In comparison with the CT, the outlet temperature of the M3 and M1 is higher by 46.2% and 40.3%, respectively. M2 gives a nearly similar fluid outlet temperature as M1. A maximum of 35.4% enhancement in heat gain compared to the CT is observed for M3 (which is best among modified configurations) under similar operating conditions. However, at 788 W/m2 solar insolation and a constant mass flowrate of 0.0167 kg/s, the estimated thermal efficiency of M1 is higher among the three models which is 33.5% higher than the CT. The experimental results closely approximate the numerical predictions with a deviation of ± 1.1 °C. From the economic evaluation of the modified collectors, a minimum payback period of 2.5 years was observed for Model 1 which is the shortest among the investigated ETSC systems.

Self-assembled peptide hydrogels have emerged as alternatives to the conventional approaches employed in controlled drug release, wound-healing, and drug delivery, and as anti-infective agents. However, peptide hydrogels possessing antibacterial properties are less explored. In this work, we have designed three ultrashort antibacterial peptide hydrogels: Fmoc-FFH-CONH

This article proposes a model to determine the optimal performance and design conditions for a flat plate solar water collector. The model uses the hourly solar irradiation data over a year for humid subtropical climatic conditions for estimating the thermal, optical, and exergy efficiency. The proposed model has been validated with the data in the literature. Six single-objective computational intelligence (CI) techniques are used to determine the maximum exergy efficiency by optimizing the plate area of the absorber, mass flow rate, and inlet temperature of the working fluid. The statistical analysis shows that the performance of water cycle algorithm is superior in every statistical parameter. Six multi-objective CI techniques are used to evaluate the trade-off solutions between the conflicting objectives of maximizing exergy efficiency and minimizing the area of the absorber plate. Three of these algorithms are able to determine the maximum exergy efficiency with the minimum absorber plate area. A MATLAB-based GUI has also been provided to help in determining the optimal values of the decision variables under various scenarios.

This study provides the first report on the complete genome sequence and host range study of eggplant infecting Carlavirus (IND-SHM isolate) causing mosaic disease in eggplant. We report the comple...

Calophyllum inophyllum is a potential source of non-edible seed oil. Calophyllum oil is used as a biofuel and also for medicinal purposes. At the Institute of Forest Genetics and Tree Breeding, Coimbatore carried out a study in 2019, on five different clones of C. inophyllum to investigate the effect of clonal variabilty on oil yield and oil physico-chemical properties for use as a biofuel. Oil yield significantly varied among the five clones and ranged from 48.6% to 55.8%. Among the physical properties, except Kinematic Viscosity, Specific Gravity and Refractive Index, the properties such as Flash point, Fire point, Pour point and Cloud point did not vary significantly. However, all the chemical properties studied, such as Acid value, Saponification value, Iodine value and Peroxide value showed apparent variation. From the study it could be derived that clone 15 is more suitable as tree crop for biofuel purpose and the variations among the clones indicate prevalence of scope for tree improvement of C. inophyllum for specific use.

Maintaining human thermal comfort and extensive power consumption of the conventional heating ventilating and air-conditioning systems drive the researchers to look for an alternative dehumidification system. Among the potential alternatives, the liquid desiccant dehumidification system has evolved as a long-term renewable and less power consuming system due to its effective controlling capability of humidity. In the present study, an experimental investigation is carried out to demonstrate the performance of lithium bromide (LiBr) and potassium formate (HCOOK) desiccant solution mixture in a spray type counterflow-packed bed adiabatic dehumidifier. Subsequently, ternary plots and 3D-contour trade-off paradigms are patterned to assess the performance parameters using an optimal mixture design methodology. Additionally, empirical correlations are developed to pattern the performance parameters (moisture removal rate (MRR), enthalpy effectiveness (ξh) and moisture effectiveness (ξm)) as a function of blend combinations. Further, the present study endeavours to explore the application of offline calibration methods based on a balanced optimum mixture design-centred desirability approach for optimizing the mixture proportion to obtain the optimal performance parameters (i.e., MRR, ξh and ξm). The wettability area is explained based on the static contact angle on a plane glass. The results showed that the contact angle was decreased from 47.3° to 44.1° for the optimum mixture of LiBr solution (37.2%-LiBr +17.8%-HCOOK), which further confirmed the higher MRR. Lastly, the tuning effect of the liquid to gas flow rate on the dehumidifier performance and economic viability of LiBr-HCOOK blends are studied.

Anthracnose of chilli causes pre- and post-harvest fruit decay, resulting in significant yield losses. We surveyed major chilli growing regions in India and identified six Colletotrichum sp. viz., ...

Current research in dehumidification systems is mainly focused on thermally driven liquid desiccant systems. However, the selection of proper desiccant solution has a greater significance on the performance of a dehumidifier. In this perspective, current work is presented with governing equations of energy, mass and species balance to study the performance of a dehumidifier. The governing equations are solved using finite difference method coupled with Jacobi’s model for an air–desiccant contact system of a cross-flow packed bed adiabatic dehumidifier operating with different desiccant blends of lithium chloride (LiCl) and calcium chloride (CaCl2) solution. The effect of variation in blend proportion on outlet parameters of a packed bed dehumidifier is patterned under various desiccant to air (L/G) mass flow rate ratios. It is observed that the addition of CaCl2 desiccant solution into LiCl changes the nature of thermo-physical properties of blends‚ which are predicted using non-random two liquid (NRTL) equation. Further, a trade-off analysis among the performance parameters is presented. It demonstrates that dehumidifier performance paradox such as enthalpy effectiveness (ɛh), moisture removal rate (MRR) and moisture effectiveness (ɛm) have a tendency to be optimal for 35% LiCl with 5% CaCl2 blend (BL1) among all blends at L/G ratio of 2. The variation of thermodynamic properties (air temperature, humidity, desiccant temperature and desiccant concentration) inside the dehumidifier module is visualized in terms of contour plots. Furthermore, the irreversibility in heat and mass transfer operation for the optimal blend is investigated in terms of physical and chemical exergy destruction paradigm. The result of such investigation elucidated that the maximum chemical exergy destruction is 0.88 kW, whereas the physical exergy destruction is 0.06 kW.

The impact of grapefruit seed extract (GFSE) as an antibacterial agent on citric acid (CA) crosslinked sodium carboxymethylcellulose (NaCMC)/hydroxypropylmethylcellulose (HPMC) hydrogel films has been studied by incorporating different quantities of GFSE. The prepared films were examined for their physical, thermal, mechanical and antibacterial properties. It was observed that crystallinity and initial decomposition temperature of hydrogel films decreased with GFSE concentration. Furthermore, the swelling degree and tensile strength of hydrogel films were found to be 257.29 ± 5.08%–162.06 ± 1.78% and 11.61 ± 0.27–2.21 ± 0.94 MPa for increasing GFSE concentration varying from 0.25% - 1.5% (v/v). The presence of nanoparticles in the films was observed by FESEM and FETEM analysis. It was confirmed that the formation of nanoparticles (micelles) is due to the addition of NaCMC and GFSE, probably glycerides, which is one of the main components in GFSE. The hydrogel films have demonstrated excellent antimicrobial activity and elongation at break (%). Moreover, zeta potential of nanoparticles was recorded to be −55.26 mV ascertaining their stability in water that contributed to a higher antimicrobial activity against gram negative bacteria. All these outcomes prove the nanocomposite films to be a potential substitute for hydrogels loaded with synthetic drugs in wound healing and other biological applications.

In this study, a numerical model is developed to study the behaviour of conventional heat sink and phase change material (PCM) heat sink for electronics cooling applications. Two different PCMs, RT35HC (ΔTm = 34–36 °C and ΔH = 240 kJ/kg) and RT44HC (ΔTm = 41–44 °C and ΔH = 250 kJ/kg), are selected for the analysis. A comparison has been made between conventional heat sink and PCM-based heat sink under constant and variable heat flux conditions. Further, four different hybrid heat sink design configurations are studied during the cooling period (solidification) and compared with PCM-based heat sink. During the heating period, the conventional heat sink is subjected to different convective cooling environments (h = 10–50 W/m2-K). The results showed that the PCM heat sink achieved base temperature equivalent to the conventional heat sink with the heat transfer coefficient between 30 and 40 W/m2-K under the constant heat flux condition. Under the variable heat flux condition, the base temperature of the PCM heat sink is very much less than the conventional heat sink subjected to 50 W/m2-K. During the cooling period, hybrid heat sinks reduced the heat transfer coefficient by ten times less than that of the PCM heat sink.

Spatial confinement of excitons in the nano-crystalline region of semiconducting nanostructures differ significantly from the optoelectronic properties exhibited by the bulk material. We report spike-like absorption observed in the UV spectrum of a phenylalanine hexamer peptide [(Ff)

Onion (Allium cepa, L) is a very important vegetable crop in India. India is the second largest producer of onion in the world and the crop is grown on more than 1.22 million hectares. Fusarium Basal Rot (FBR) is an economically important diseasef onion that causes considerable losses in onion production up to 50% in field and 30-40% during post-harvest storage of bulbs (Gupta and Gupta 2013; Rajamohan et al. 2019). Onion plants showing chlorosis, twisting, wilting, necrosis, bulb discoloration, rot in the basal parts of bulb and roots typical to FBR were observed, in a field trial of 36 onion cultivars during October 2020 in Bangalore, Karnataka. FBR incidence varied from 30-100% in this field (Fig 1 a-d). Symptomatic bulbs were washed with water, basal plate and fleshy leaves cut into 0.5 to 1 cm-size, surface disinfected with 1.5% sodium hypochlorite (NaOCl) for 3 min, and rinsed with sterile distilled water. Twenty pieces were placed on potato dextrose agar (PDA) in Petri plates and incubated at 25°C for 7 days. Colonies from single-spore isolates on PDA showed abundant white aerial mycelium. Colonies showed light pink or purple coloration on the reverse side of the culture plate with brown center (Fig 1e-f). Macroconidia were 19.13 to 28.35 (mean= 24.2) × 4.29 to 6.06 (mean= 5.05) µm, hyaline, falcate, with slightly curved apexes, and three to five septa. Microconidia were cylindrical to ellipsoid, aseptate, hyaline 8.20 to 12 (mean=10.0) × 3.55 to 4.79 (mean= 4.29) µm (Fig 1g). Chlamydospores were round, intercalary, hyaline, single or in chains (Fig 1h). Two isolates (IBFF-09IBFF-10) were analyzed for internal transcribed spacer-ITS (White et al. 1990) and translation elongation factor 1-α (tef1) gene (O'Donnell et al. 1998) by polymerase chain reaction (PCR) and sequenced. ITS and partial tef1 gene sequences of isolates IBFF-09 and IBFF-10 were submitted to the NCBI database (GenBank accession # ON394614ON026859; # ON409480, ON093166 respectively). Phylogenetic analysis of tef1 gene placed the isolates with F. falciforme (Fig 1i). A pathogenicity test was performed by dipping roots of 28 days old healthy onion seedlings of a susceptible genotype 16/7Y GR3 into a conidial suspension (1 × 104 conidia/ml) of isolate IBFF-10 for 15 min and then transplanting the plants into pots containing sterilized potting mix. Inoculated plants developed typical symptoms of FBR and were all dead by 20 days post inoculation (Fig 1j) while the non-inoculated controls remained healthy. Pathogen was re-isolated from infected plants and showed the same morphology, ITS and tef1 sequence similarity as the original isolate, thus fulfilling Koch's postulates. Basal rot of onion by F. falciforme is reported from Mexico (Tirado-Ramírez et al. 2021). Till date, only F .oxysporum, F. proliferatum and F. solani have been implicated in onion FBR in India (Lee et al. 2021; Rathore and Patil, 2019). F. falciforme however, i prevalent in India and is reported to infect other crops (Gangaraj et al. 2022; Gupta et al. 2019; Homa et al. 2018). There is a high probability that this pathogen is contributing significantly to basal rot disease but it has not been reported yet. To our knowledge, this is the first report of F. falciforme infecting onions in India. In order to develop FBR resistant onion cultivars it is critical to identify and study the response of onion genotypes to different Fusarium spp causing the disease.

The ability to modulate self-assembly is the key to manufacture application-oriented materials. In this study, we investigated the effect of three independent variables that can modulate the catalytic activity of self-assembling peptides. The first two variables, amino acid sequence and its stereochemistry, were examined for their specific roles in the epitaxial growth and hydrogelation properties of a series of catalytic tripeptides. We observed that aromatic π-π interactions that direct the self-assembly of designed peptides, and the catalytic properties of hydrogels, are governed by the position and chirality of the proline residue. Subsequently, the influence of the third variable, an external electric field, was also tested to confirm its catalytic efficiency for the asymmetric C-C bond-forming aldol reaction. In particular, the electric field treated pff and PFF gels showed 10 and 36% higher stereoselectivity, respectively, compared with the control. Structure-property analysis using CD and FTIR spectroscopy indicates the electric field-induced beta to non-beta conformational transition in the peptide secondary structure, which corroborates with its reduced cross-link density and fibril width, respectively. Amplitude sweep rheology of the gels suggests a decrease in the storage modulus, with increased field strength. The results showed that an electric field of optimal strength can modulate the physical characteristics of the hydrogel, which in turn is manifested in the observed difference in enantioselectivity.

Air conditioning systems are used to control the air dry-bulb temperature and humidity level for human thermal comfort. In order to control the humidity level, air dry-bulb temperature needs to be brought down below its dew point temperature to condense out the moisture from the air. This eventually consumes a significant amount of total building energy in terms of electricity. Therefore, to minimize the energy consumption, researchers are stimulating their study towards an alternative latent heat load control system. In this regard, desiccant based sorption technologies are more effective compared to the conventional vapor compression system. Therefore, it is necessary to analyze the different desiccants' individual properties and their physical behavior in material perspective. In this study, an effort is devoted to explore the thermo-kinetic properties of pure LiBr, CaCl2, as well as their mixtures (LiBr:CaCl2 of 90:10; 85:15; 80:20 and 75:25) by X-ray diffraction (XRD), thermo-gravimetric (TG) and absorption rate, analyzes through numerous control experiments. The XRD study confirmed that peaks of CaCl2 and LiBr were shifted slightly for LiBr and CaCl2 mixtures due to interaction effects. The results of present investigation elucidated that mixtures of LiBr and CaCl2 showed less moisture regeneration cost than pure CaCl2 and all the mixtures revealed more rate of moisture absorption than pure LiBr and CaCl2. Further, 85:15 mixture of LiBr:CaCl2 showed higher rate of moisture absorption when compared to other prepared samples.

Solar collectors are efficient in utilising solar thermal energy for heating applications as their efficiency is quite high even in the medium temperature range, which motivated to design a high efficient collector system. In this study, an experimental investigation is carried out by developing a series of evacuated tube solar collectors with U-tube configuration using water as a working fluid. The performance of the collector system is continuously measured throughout the day. A trade-off study is carried out considering all the performance parameters. On the basis of experimental datasets, a multilayer perceptron (MLP) architecture is developed to predict thermal efficiency, useful heat gain and water outlet temperature of the evacuated tube collector as a function of solar irradiation, mass flow rate of water and water inlet temperature. It is demonstrated that the MLP model has an excellent agreement with experimental data as the mean square error is very low (

Visualization of heat flow and trajectories has been employed during buoyancy induced (natural) convection within porous rhombic 2D cavities of different base angles involving various inten...

In this study, zinc-sulfate-calcium-phosphate (ZSCAP) ceramics was prepared by calcination in the presence of microwave irradiation using precursors ZnSO4:ZnO:CaO:P2O5 in a ratio of 15:30:30:25 (by weight). The calcined ZSCAP ceramics was mixed with microcrystalline cellulose and it was further heated by microwave radiation for the preparation of cellulose/ZSCAP nanocomposites. It was found that microwave heating time played an important role in the crystalline phase of synthesized nanocomposites of cellulose/ZSCAP. Well-crystalline phases of calcium phosphate, zinc oxide and zinc sulfate were observed in the nanocomposites at 20 min of microwave heating time. Fourier transformed infrared spectroscopy (FTIR) and Raman spectroscopy confirmed that the obtained products were of cellulose/ZSCAP nanocomposites. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images indicated that reinforced ZSCAP nanostructures were embedded into cellulose matrix. Energy dispersive X-ray spectroscopy (EDS) further supported the presence of Zn, S, Ca and P in cellulose/ZSCAP nanocomposites. The thermal behavior of the products was studied using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The prepared nanocomposites showed antibacterial activity against Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity assay revealed that the prepared nanocomposites had no influence on proliferation of MG-63 cells. This rapid microwave-assisted method is simple, fast and suitable for the production of cellulose/ZSCAP nanocomposites, which finds its biomedical applications in tissue engineering and bone repair.

Recently, sorption technology has taken significant attention as an alternative process to mechanical air conditioning systems for dehumidification of air without lowering the air dry-bulb temperature below its dew point temperature. In this perspective, an aqueous lithium chloride (LiCl) is considered as a more effective desiccant in desiccant sorption systems due to its higher moisture absorption capability. In the present study, an effort is made to develop a simple correlation to predict the vapour pressure of LiCl solution as a function of solution temperature and concentration. Based on the developed correlation, an Othmer chart is constructed for LiCl solution in the concentration range of 20–40% and 15–50 °C temperature range. A trade-off analysis has also been carried out among the performance parameters. It is shown that venture of optimum outcome is observed at solution to air flow rate ratio of 8.5 with a condensation rate, moisture and enthalpy effectiveness of 0.234 g/s, 71.5% and 72.5%, respectively. Subsequently, empirical regression models are developed for predicting the performance parameters, which reveals that the developed models are robust for surrogate modelling in dehumidifier testing paradigms.

In the current study, a combined conduction-convection model is developed to analyze the effect of natural convection inside the Phase Change Material (PCM) during melting and solidification processes of a cascade Latent Heat Thermal Energy Storage System (LHTESS) and it is compared with pure conduction model. Effective heat capacity method is employed to simulate the phase change phenomena in both combined model and pure conduction models. Boussinesq approximation is used to predict the effect of natural convection inside the PCM in the combined model. The governing equations involved in the model are solved using finite element based simulation software, COMSOL Multiphysics 4.3a. Parametric study is conducted on charging and discharging processes of cascade LHTESS using both the models. The comparative study between combined model and pure conduction model demonstrated that the pure conduction model under predicts the rate of heat transfer between HTF and PCM at lower inlet velocity of HTF, where natural convection plays a significant role in the phase change phenomena. The deviation between the models decreases with increase in the inlet velocity of HTF for both charging and discharging processes. The simulation results indicated that the heat transfer phenomena inside the PCM become more conduction dominant at higher inlet velocity of HTF. The results also revealed that the inlet temperature of HTF plays a major role in decreasing the charging/ discharging time.

In this study, a weight ratio of 50:30:20 of ZnO:CaO:P2O5 was calcined using microwave and conventional thermal treatment at 800 °C to synthesize zinc oxide calcium phosphorous oxide (ZCAP) ceramics. X-ray diffraction data indicated that microwave synthesized ZCAP ceramics was less crystalline than conventionally synthesized ZCAP. Micro-Raman spectroscopy and FTIR confirmed the presence of ZnO, phosphate and carbonate groups in both heat treatment methods. The reported TGA-DSC results demonstrated that carbonate amount was very less (approx. 0.1%) in microwave synthesized ZCAP while in comparison to carbonate amount was high (approx. 0.69%) in conventionally prepared ZCAP. FESEM image analysis showed that particle sizes were comparatively smaller for microwave synthesized ZCAP than conventionally synthesized ZCAP. Hence, microwave calcinations of ZnO, CaO and P2O5 is a promising method to synthesize ZCAP ceramics compared to conventional thermal calcination treatment.

The performance of an extruded finned plate air heating solar collector is studied theoretically for paddy drying applications. Climatic conditions and solar radiation data are accounted based on Guwahati region (26.11˚N, 91.72˚E). Outlet air temperature and pressure drop are considered as controlling parameters to find optimum number of fins, fin height and fin thickness. Outlet air temperature increases and then decreases with number of fins whereas pressure drop increases with number of fins. The analysis showed that finned plate air heating solar collector with 80 fins, 0.6 Height (H) to-Duct length (D) ratio and 2 mm fin thickness yield best results for paddy drying applications at Guwahati weather conditions.

In this study, hydrogel films were prepared from sodium carboxymethylcellulose (NaCMC) and hydroxypropylmethylcellulose (HPMC) using citric acid (CA) as crosslinker. The chemical crosslinking (ester bond) between NaCMC and HPMC was confirmed by FTIR analysis. It was found that swelling degree, crystallinity and water contact angle of hydrogel films based on NaCMC-HPMC (2wt%) decrease with increase in CA from 5% to 20% (by weight). The increase in Tg and decrease in initial decomposition temperature were observed for increasing CA in NaCMC-HPMC films and were confirmed by DSC and TGA analysis, respectively. Tensile strength of hydrogel films decreases while elongation at break (%) increases with increase in CA. Highly interconnected nanoporous network and decrease in average pore diameter from micron to nanosize in cryofixed hydrogel films were found by FESEM and mercury intrusion porosimetry, respectively. The drug loading efficiency of hydrogel films was significantly higher for methylene blue compared to tetracycline. It was observed that hydrogel films release the drugs in sustained manner for 72h. The hydrogel films showed significant antibacterial activity after three days of release at 37°C in PBS (pH7.4). These findings strongly recommend that the prepared hydrogel films can be used as potential wound healing materials.

Liquid desiccant dehumidification is a promising energy-extensive process for air dehumidification, which can easily be driven by any waste or renewable heat sources. In the current study, a hybrid method is proposed by combining the solar evacuated tube collectors as a regeneration source to drive liquid desiccant system in a close-loop. Subsequently, an experimental setup has been fabricated to assess the performance of the overall system using a novel desiccant mixture. The overall energy balance between the ambient air and the liquid desiccant was also studied. Effects of independent parameters such as solution to airflow rate, solution concentration and temperature on the dehumidifier-regenerator performance parameters such as latent heat ratio, condensation rate, desiccant mass fraction index, evaporation rate, latent and enthalpy effectiveness were analyzed. The result of present investigation showed that high solution to airflow (S/A) ratio enhanced the dehumidification and low S/A ratio enhanced the liquid desiccant regeneration rate. The maximum latent heat ratio for the dehumidifier at the design condition was 0.92, and the thermal coefficient of performance of the system was found as 1.1. The airside pressure drop in the dehumidifier/regenerator was also estimated at different flow rates of desiccant. Further, adaptive neuro-fuzzy inference system (ANFIS) prediction models are developed to predict the system performance as a function of system-independent parameters. The model results exhibited a good agreement with the experimental outcomes. The latent heat ratio and evaporation rate are predicted within a mean absolute percentage error (MAPE) of 2.7% and 2.3%, respectively.

In last few decades, a substantial advancement has been observed in dehumidifier modules for their energy-conservative and environment-friendly nature; however, still uncertainty in decision-making is of concern in selection of optimum input parameters to attain an effective performance. In this perspective, an experimental study is performed in an adiabatic packed bed, counter-flow liquid desiccant dehumidifier fuelled with the blend of lithium bromide and calcium chloride solution at various operating conditions with different control settings. It is observed that air mass flux rate (Fa), solution concentration (ζ) and air specific humidity (ωa) have significant impact on condensation rate (CR), whereas, air mass flux rate (Fa) and solution temperature (Ts) are the most effective parameters for moisture effectiveness and latent heat factor, respectively. The experimentally obtained results for multiple response performance characteristics are represented based on inlet process parameters using gene expression programming (GEP). The proficiency of developed GEP meta-models is provided by statistical parameters, Taylor diagram and Theil uncertainty. Subsequently, GEP meta-model based fuzzy logic is developed for optimising dehumidifier inlet process parameters in terms of multi-responsive performance characteristics using Genetic Algorithm. The optimisation results showed that dehumidifier performance characteristics have a tendency to become optimal at Fa = 0.766 kg/m2-s, Ta = 30.745 °C, ωa = 0.023 kgwv/kgda, Fs = 1.812 kg/m2-s, Ts = 24.01 °C, and ζ = 48.1%. Finally, experiments were conducted at optimum conditions and observed proximity between the predicted and experimental outcomes, which further validates the current optimisation approach.

In this study, the influence of grapefruit seed extract (GFSE) was studied on citric acid and zinc oxide incorporated cellulose-based hydrogel films. The effect of GFSE (0.25–1.0%, v/v) on hydrogel films was examined for their physico-chemical, mechanical, thermal, antioxidant and antibacterial properties. The swelling ratio, tensile strength and thermal stability of films decreased with increase in GFSE concentrations. On the other hand, elongation (%) and antioxidant activity of films were found to be 34–60% and 25–79%, respectively for increasing amounts of GFSE. FESEM and FETEM clearly showed that two different types of nanoparticles (50–90 nm and 5–10 nm) were present in GFSE incorporated films. The release of polyphenolic compounds and zinc from films was in sustained manner. Furthermore, the fabricated hydrogel films exhibited antibacterial activity against both E. coli and S. aureus. All these results indicate that the prepared nanocomposite hydrogel films could find their potential applications in wound healing.

The existing food packaging materials made up of fossil fuel-based polymers pose a serious threat to the environment. This is the motivation behind the extensive research on biopolymer sources including polysaccharides, proteins and lipids so as to produce biodegradable food packaging materials. Amongst the existing biopolymer sources, commendable attention has been diverted to polysaccharide materials due to their abundancy, film-forming abilities and good gas barrier properties. Despite their desirable properties, polysaccharide-based films demonstrate a poor water barrier and mechanical properties. Further, they are expensive in comparison with conventional plastic materials which restrict the commercialisation. In this regards, an extensive research effort has been made to improve the inherent properties exhibited by the biopolymer-based films by fabricating composites, nanocomposites, blends and addition of cross-linking agents. Amongst available, starch is a kind of polysaccharides consisting of different ratios of amylose and amylopectin, which determines its property. Modified starch with other polymers/nanofillers exhibits improved film properties. In addition, cellulosic derivatives as ionic binders are of a good choice in controlling the moisture and also enhance the mechanical properties of food packaging films. Moreover, chitosan like polysaccharide exhibits an antibacterial activity which is an important property to produce films of higher shelf life and to maintain product integrity. The quest for producing low-cost biodegradable food packaging films derived from polysaccharides with better water barrier and mechanical properties is a never-ending process and demands a multidisciplinary approach to accomplish this goal. The present chapter mainly focuses on recent research accomplishments on polysaccharide-based films for food packaging applications.

Tomato fruits with typical anthracnose symptoms of small, sunken, dark brown lesions were observed in the farmers fields in Jalna, Maharashtra, India. Based on morphological and molecular characterization, the fungus was identified as Colletotrichum truncatum, which is reported for the first time causing anthracnose on tomato in India.