Search

A biodegradable film was developed using an ionic liquid as a plasticiser, and rice starch having medium amylose content. The physical, mechanical and electrical properties of the developed films were determined and analysed employing the principles of chemometrics. The water vapour transmission and elongation of the films increased with 1-butyl-3-methylimidazolium chloride (BMIMCl) concentration. The highest melting temperature was 133.4°C when the concentration of BMIMCl was 4% (w/w). The crystallinity and extent of modification were characterised by XRD and FTIR. The highest conduction of film was 0.29 S/m while the lowest resistance observed was 3.42 Ωm. The chemometric analysis of parameters of the film was carried out in terms of hierarchical cluster analysis (HCA) and principal component analysis (PCA). This study demonstrated the possibility of using rice starch with BMIMCl as the plasticiser to design an electroconductive film having the desired heating characteristics.

Main issues of large-scale and large-area production of the solar cell are the high cost of fabrication due to the involvement of costly and sophisticated equipment and the use of costly materials in fabrication. Here, an effective and low-cost approach has been proposed for the fabrication of reduced graphene oxide (rGO)–ZnO/silicon heterostructure solar cells. The hybrid composite of rGO–ZnO has been synthesized by using a low-cost chemical method and deposited on a pcSi substrate by a sol-gel process for application in heterojunction solar cells. The morphology, crystal phase, surface functional groups, and optoelectronic properties of the heterostructure have been investigated by using SEM, XRD, the Fourier transform infrared (FTIR) spectroscopy, the Raman spectroscopy, and the UV-vis spectroscopy. The ${I}$ – ${V}$ characteristics of the fabricated heterojunction cell show a power conversion efficiency of 4.35% ( $V_{\text {oc}}= {0.51}$ V, ${J}_{\text {sc}}= {14.47}$ mA $\cdot $ cm−2, and fill factor (FF) = 51.60) due to having enhanced conductivity/charge transfer efficiency by the hybrid semiconductor. This simple approach assures the low-cost mass production of heterojunction solar cells.

Green synthesis method is an effective approach for reduction of graphene oxide (GO) and the surface tuning of graphene nanosheets. In this work, facile green approach for the reduction of graphene oxide was adopted by utilizing phytochemical extracts of Citrus grandis (Pomelo) and Tamarindus indica (Tamarind). FTIR analysis showed significant reduction/elimination of the peaks that corresponds to the oxygen containing groups. XRD and Raman analysis confirmed the successful reduction of GO after treating with fruit extracts. The morphological analysis by SEM and TEM images further confirmed the formation of graphene nanosheets. The conductivity of both Pomelo-rGO (P-rGO) and Tamarind-rGO (T-rGO) were found to be 104-folds higher than that of GO. The electrochemical characterization of the synthesized rGO was done by cyclic voltammetry (CV). Specific capacitance of 65.25 F/g and 47.33 F/g were recorded for T-rGO and P-rGO, respectively. The results showed that this green synthesis route is promising for the large-scale production of rGO.

Electrochemical water splitting has brought clean route of green energy generation through its hydrogen evolution capability having no environment impact in the form of global warming. The related technology experiences challenges associated with cost, durability and mass production of hydrogen separated from water. Proper morphological design of highly active and low cost materials for both electrodes and electro-catalyst has become essential to deal with these issues. Here iron alloy cylindrical electrodes with screw pitched morphology and low cost ferrous hydroxide nano-particles have been introduced as an electrode and electro-catalyst respectively in compact integrated water electrolysis cell to catalyze both reactions in same electrolyte. Theoretical model of screw pitched electrode has been made to enhance sharp surface area for efficient Hydrogen and Oxygen evolution. It demonstrates water electrolysis using low cell voltage of 1.68 V at current density of 500 mA/cm2 with long term durability over 80 h having utilization efficiency of 73.88% and Faradaic efficiency of 80.714%. The experiments including high speed synthesis of nano-catalysts performed at room temperature provide guarantee of saving energy. This works promises a significant move towards mass production of hydrogen fuel through inexpensive method of water splitting.

This article presents a low-cost fabrication of binary/coupled ZnO–SnO2 composite semiconductors for heterojunction solar cells using a simple and effective sol-gel approach. Here, the synthesis and characterization of coupled ZnO–SnO2 nanocomposites are carried out with varied stoichiometry designated as ZnO–SnO2(20:80), ZnO–SnO2(50:50), and ZnO–SnO2(80:20). The X-ray diffraction (XRD) spectra confirmed an excellent crystalline domain in the order of ZnO–SnO2(80:20) > ZnO–SnO2(50:50) > ZnO–SnO2(20:80). Nanorods formation of ZnO–SnO2 has been confirmed through the scanning electron microscopy (SEM) micrograph. The improvement in photoconversion efficiency of solar cell from 3.39% to 3.98% was achieved due to increasing photo-excited free carrier generation with a significant change of nanorods dimensions. Furthermore, the UV–vis spectroscopy exhibited impressive transmittance of 85% in the wavelength range of 200–1000 nm. A bandgap modulation of 3.66–3.40 eV has been achieved. The power conversion efficiency (PCE) of 3.98 ( ${J}_{\text {sc}} = {18.83}$ mA/cm2, ${V}_{\text {oc}} = {0.581}$ V, and FF = 36.37) is determined using ZnO–SnO2(80:20), which is almost twice of that of a single semiconductor-based Al/ZnO/p-Si/Al solar cell.

In the present investigation, a paper-based pH indicator was developed using anthocyanin from purple rice bran for rapid food quality monitoring. The efficiency of the indicator was studied in different buffer solutions of pH range 2–10. The indicator was made with 150 mg/L anthocyanin concentration shows a distinct L, a, and b values of color. Furthermore, the indicator was tested in different liquid foods with varying pH and indicating distinct color in every pH value. The degradation behavior of a value (redness) of the indicator was investigated in 4 and 25 °C. The degradation behavior at 4 and 25 °C was best fitted with first-order kinetics (R2 = 0.99 and 0.97) than zero-order (R2 = 0.98 and 0.96). In addition, the performance of the indicator was compared with the previous research observations. The present study manifested a green route of monitoring for liquid food quality using low-cost and highly sensitive pH indicator.

A fast and efficient route is a key challenge in synthesis of graphene oxide (GO). In the present work, we report the synthesis of highly oxidized graphene (HOG) via 2 step chemical oxidation method by using a mixture of H2SO4 and HNO3 as the intercalating and initial oxidizing agent followed by KMnO4 as the final oxidizing agent. The XRD results of HOG showed peaks at 2θ = 9.7 (d spacing = 9.1 A) which is the largest ever reported in such a short synthesis time. Raman spectroscopy confirmed the XRD results which proved that HOG is highly oxidized. UV–vis spectra provided evidence of the presence of an ample number of oxygen functionalities, such as hydroxyl, carboxyl, epoxide, and carbonyl on graphene oxide. SEM results exhibited the presence of wrinkles and folds along with a rough surface in HOG. The GO prepared by this method took only 3.5 hrs and is more oxidized compared to the ones prepared by Hummers method.

Artificial photosynthesis based on solar guided water splitting is essential to obtain green renewable energy sources which is a potential replacement of fossil fuels. This paper presents a water splitting design with proper choice of non-precious and easily available composite metal (Fe, Ni, Mn and Al) based electrode to evolve the cleanest form of H2 and O2 separately through water electrolysis with a low voltage of 1.6 V using NaOH electrolyte of pH 12.7. The power supply embedded with solar panel connecting to the electrodes (anode/cathode) is maintained at a voltage level of 1.5–5 V in order to initiate the electrolysis process (electrolyte NaOH, pH = 12.7). This process leads to movement of H+ and OH− ions to cathode and anode kept within the gas chambers and the H2 gas evolved is stored. Experimental results show a high rate of H2 evolution that falls in the range of (7.3 × 1015 to 37.3x 1015) molecules s−1 and current density is found to be 2.6 mA cm−2 at 1.6 Volt which is far better than that of many state-of-the-art techniques. The proposed design setup along with the composite materials based electrode, produces a high rate of Hydrogen gas from H2O with high current density in low voltage.

Complex multi-photon quantum interference states are indispensable requisites for integrated quantum optic processing and quantum communication technologies. Here, two mode interference (TMI) coupler has been presented to demonstrate HOM model of multi-photons (N > 2) Quantum interference. The experiment of three and four photons quantum interference have been performed and coincidence rate of three and four photons quantum interference have been measured and quantum visibilities are obtained as ∼ 0.783 ± 0.009 and ∼ 0.85 ± 0.009 respectively at 3 dB TMI coupling length of 11.5 μm. High fabrication tolerance of quantum fidelity of TMI coupler has been achieved due to having less number of design parameters in comparison to directional coupler and multimode interference coupler. Our results pave the way to achieve multi-photons quantum entanglement in compact device.

This paper proposes a cost-effective sol–gel method for synthesis of ZnO nanostructure to make Al/ZnO/p-Si/Al heterojunction solar cell. Here, crystalline ZnO nanostructure was grown on p-silicon and annealed at 300 °C, 400 °C and 500 °C for application in heterojunction solar cell. The optimum temperature for obtaining uniform crystalline nanostructure was 500 °C, as confirmed from XRD and SEM imaging. As investigated by UV–Vis spectroscopy, the ZnO nanostructure layer exhibited high transmittance in the visible spectrum and has a direct band gap of 3.26–3.28 eV. The power conversion efficiency of Al/ZnO/p-Si/Al solar cell is enhanced from 1.06 to 2.22% due to increase in surface area of ZnO by formation of crystalline nanostructure due to increase of annealing temperature. The optimum value of short-circuit current (Isc) and open-circuit voltage (Voc) was measured using current–voltage (I–V) under AM 1.5 illuminations and found to be 9.97 mA and 460 mV, respectively.

The infected lung of COVID-19 patients has four stages–early, progressive, peak, and absorption. Clinical analysis is required for the treatment of COVID-19 patients. In this direction, chest-computed tomography (CT) plays an important role. The extraction of clinical features of infected lungs from Chest CT images needs the image processing techniques to suppress the image information of other organs located in the chest. Here, we have applied a quantum edge extraction algorithm on a chest CT image to extract clinical information such as ground glass opacity (GGO), crazy paving pattern (CPP), and consolidation that appeared in four stages of COVID-19. We have extracted more sharp edges, specifically in the smooth regions of clinical patterns, using our proposed approach compared to other existing operator-based edge extraction algorithms. The analysis of extracted images can assess the damage of infected lung of the above stages of COVID-19 patients immediately after admitting to the hospital and may help the physician for continuous monitoring of patients during the treatment of severe acute respiratory symptoms caused due to COVID-19.

An optical pulse controlled 2x2 two mode interference (OTMI) coupler having silicon core surrounded by Graphene clad has been introduced as fundamental gates of optical processing. Considering strong light –matter interactions and nonlinear optical property of graphene, we have shown coupling characteristics depending on additional phase change between the excited surface plasmon polariton modes propagating through the silicon core. By applying optical pulse energy of 0.82 pJ and width of 4 ps on graphene clad, the NOT, AND, and OR logic gates are demonstrated. The coupling length of the proposed device is ~ 3.2 times less than that of already reported optical device based on SPP modes. Our results promise to obtain the development of integrated of optical processor with high speed, compact and low power optical logic gates having high fabrication tolerance.

Citrus fruits exhibit a high level of different phytoconstituents, of which the changes in the different parts of the fruit during ripening have not been thoroughly studied yet. Thus, in this study, we have investigated how different parts of pomelo fruit (Citrus grandis L.) are modified throughout the development of two consecutive growing seasons. In detail, the main phytochemical compounds, such as total phenolic content, total flavonoid content, antioxidant capacity, DPPH free radical scavenging activity, Ferric reducing antioxidant power (FRAP), and naringin and tannin content, were analyzed. A systematic metabolism of these compounds was found during the development of the fruit, but some pomelo tissues showed a fluctuating trend, suggesting a dependence on the different growing season. Focusing on the tissue distribution of these compounds, the fruit membrane contained the highest level of total phenolic and flavonoid content, fruit flavedo displayed the highest antioxidant capacities and FRAP activities, whereas maximum accumulation of naringin was noticed in fruit albedo. Instead, the highest DPPH free radical scavenging activity and tannin contents were found in the pomelo juice. Regarding the distribution of compounds, a possible bias pattern for the accumulation of those compounds has been noticed throughout the fruit development. From the GC-MS analysis, a total of 111 compounds were identified, where 91 compounds were common in both seasons. Overall, these results could be useful for the food processing industry as guidelines for excellent quality foods and for introducing health-beneficial products and components into our daily diets.

Graphical abstract, Highlights • Resin and enzymatic hydrolysis combined with sonication is applied for the first time. • Sonication-assisted resin debittering results in a lowered level of bitterness. • Sonication markedly influenced the phytochemical properties of pomelo juice. • Sonication assisted enzymatic hydrolysis improved the flavor, chemical and phytochemical properties. • Significant improvement in enzymatic activities and degradation of naringin., In the present study, sonication assisted debittering of pomelo fruit juice was carried out and the effect of sonication along with resin/enzyme on the chemical, phytochemical and volatile composition of juice was also investigated. The optimum conditions for sonication coupled debittering using resin were 50 kHz, 2 min, and 45 ℃ while 50 kHz, 60 min, and 60 ℃ were obtained for enzyme hydrolysis. Sonication treatment not only reduced the debittering time but also enhanced the adsorption and hydrolysis of naringin by 17% and 20% in resin and enzyme respectively. In addition, enzymatic activity was also improved and weakened C-O bonds in naringin. At the same time, sonication significantly affected the bioactive compounds of juice, chemical composition, and volatile compounds of juice. Flavor compounds including octanal, linalool, citral, and ethyl butyrate were enhanced by sonication-assisted enzymatic treated juice.

Polyaniline–graphene quantum dots (PANI–GQDs) are considered as an important candidate for applications in photovoltaic cells. In this work, GQDs were prepared using sono-Fenton reagent from reduced graphene oxide (rGO). PANI–GQD hybrid was also synthesized using the chemical in situ polymerization method. The synthesized materials were characterized using UV–visible (UV–Vis) spectroscopy, photoluminescence (PL) spectroscopy, current–voltage (I–V) characteristic, thermal gravimetric analysis (TGA), Raman spectroscopy, and X-ray diffraction (XRD). Dynamic light scattering was also used to estimate the lateral size of GQDs. The enhanced visible-light absorbance in the hybrid was confirmed by UV–Vis analysis and the decrease in intensity around 3461 cm−1 in FT-IR spectra was due to the interaction between functional groups of PANI with GQDs. This led to improved thermal stability and conductivity as observed from TGA and I–V analysis, respectively. Moreover, the Raman spectrum for PANI–GQDs showed a decrease in the peak at ~ 1348 and ~ 1572 cm−1 as compared to PANI and GQDs. Similarly, from the XRD profile of PANI–GQDs, a shift in peak was observed due to an alteration in the microstructure. A sandwich device with cell structure glass/ITO/PANI–GQDs/Al was fabricated and its application was tested. Current density–voltage (J–V) curve of the device was measured with a Keithley SMU 2400 unit under an illumination intensity of 100 Wm−2 simulating the AM 1.5 solar spectrum. The hybrid exhibited photovoltaic properties, and 0.857% efficiency was observed in response to the applied voltage. This work suggests that PANI can be used as an alternative material for photovoltaic cells.

Limonin, a highly oxygenated triterpene biomolecule of citrus fruits is responsible for delayed bitterness of its juice lowering consumer's acceptability. Hence, limonin detection is essential for appropriate debittering intrusions. A novel interdigitated capacitive sensor using magnesium silicate-poly vinyl alcohol (MgSiO

Here, Graphene clad plasmonics waveguide is introduced as a two surface plasmonic polariton modes interference (GTSPPMI) coupler to obtain optically manipulated quantum interference. The manipulation of Handel Ou Handel (HOM) quantum interference is demonstrated theoretically in nano-scale two modes coupler through refractive index modulation in Graphene clad with incidence of an ultra fast optical pulse energy. The quantum entanglement of fidelity ~ 97.5% is obtained by incidence of optical pulse of energy 5.12 pJ and width 3.8 ps in Graphene cladding. Our results promise to obtain fast and compact optical reconfiguring of quantum plasmonics circuit in comparison to electrooptic and themooptic coupler.

ZnO nanostructures are promising for a wide range of applications, including gas sensors. Ethanol sensing using ZnO remains unexplored though. In this paper, we report ethanol-sensing using un-doped ZnO nano flowers and Mg doped ZnO nano flowers. These are grown using a rather simple chemo-thermal process, making this a plausibly scalable technology. To study the structural and morphological properties of undoped ZnO and Mg doped ZnO nanoflowers, Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), x-ray diffraction and Field Emission Scanning Electron Microscopy (FESEM) are carried out. Ethanol sensing properties of undoped ZnO and Mg doped ZnO nanoflower devices are investigated toward different ethanol concentration (concentration range of 1–600 ppm at 100°C–200°C). Our findings show that 15% Mg doped ZnO nano flower is better than ZnO nano flower for ethanol gas-sensing applications.

Maturity determination of pomelo fruits having health-benefiting attributes is an important issue to enhance the quality of harvesting. Here, an interdigitated electrode (IDE) based sensor is introduced to detect its maturity by determining the naringin content. The sensor was made by depositing amberlite IRA-400 as a sensing layer on IDE patterned PCB substrate at room temperature with hydrothermal and spin-coating techniques. The sensor exhibits excellent selectivity for naringin, high sensitivity of 0.008 µA for 10 ppb of naringin, and reusability up to 3-4 times for naringin quantification in maturity testing of fruits. The pomelo fruits start to mature when maximum values of current response and naringin content are found at 140 DAFS. The naringin content decreases as maturity progresses and maximum phytochemical attributes were obtained at 180-220 DAFS. The IDE sensor assures an appropriate period of plucking of pomelo fruits improving harvesting practices and trade of citrus fruits.