Asymmetric ion transport through "Janus" MoSSe sub-nanometer pores.

We conduct all-atom molecular dynamics simulations to systematically investigate the underlying mechanisms governing ion transport through a sub-nanometer pore decorated with negative charges in a "Janus" MoSSe membrane. The charge imbalance between S and Se atoms on each side of the membrane induces different types of ion adsorption processes depending on the pore inner charge configuration, and the polarity of external biases, which leads to asymmetry in ionic I-V characteristics. Statistical analysis of the total translocation times including adsorption-desorption processes, and ion dwell times indicates that potassium ions predominantly remain adsorbed during their interaction with the membrane before undertaking a quick translocation through the pore. High applied biases suppress cation adsorption, which results in fast translocation with the current flow boosted by negative inner charges around the pore. We also show that in a membrane consisting of several "Janus" layers, the applied bias necessary to overcome the sub-nm pore barrier increases with the number of layers, providing control over the ionic current.

Environmentally sustainable ethyl levulinate synthesis from delignified sugarcane bagasse using ternary eutectic solvent under MW-xenon irradiation: engine performance and emission assessment.

For the first time, a synergistic energy-efficient combination of microwave-xenon (MW-XE) irradiations in presence of photoactive ternary acidic deep eutectic solvents (TADES) has been applied for intensification of ethyl levulinate synthesis from delignified sugarcane bagasse (DSB) under mild (90 min, 90 °C) and environmentally benign process conditions. The Taguchi orthogonal designed optimized conditions (20 W/cm3 of MW specific irradiation power input, 1 mol/mol of FeCl3 to citric acid ratio, 90 min of reaction time, 150 W of XE specific power input) rendered maximum 61.3 mol% of EL yield (selectivity: 87.70 [Formula: see text] 0.5%). Remarkably, synergistic effect of MW and XE irradiation significantly enhanced the EL yield (61.3 mol%) compared to the individual MW (34.52 mol%) and XE (22.67 mol%) irradiation at otherwise optimized reaction conditions. Moreover, the MWXE irradiated reactor (MWXER) exhibited a significant 79.10% increase in EL yield compared to the conventional thermal reactor (CTR), at the expense of 10% less energy consumption. The ethyl levulinate could be recovered efficiently through green protocol from reaction mix resulting in high purity (97 [Formula: see text] 0.5%) and TADES was sustainably reused in the process. The optimally generated product EL when blended (5 and 10 vol.%) with B10 and B20 (10% and 20% biodiesel-diesel blend) could provide 21-31% reduction in HC and 7.3-36% reduction in CO in comparison with petro-diesel. It was also explored that, at similar optimal parametric combinations, the TADES produced 29.5% greater EL yield in comparison with the standard ionic liquid BMIMCl. The life cycle environmental impact analysis (LCEIA) of the overall process revealed that the 5 vol.% EL blending with B10 contributed lowest environmental impacts mitigating marine ecotoxicity, human toxicity, fossil depletion, and climate change by 77.9%, 77.4%, 78.4% and 77.5%, respectively.

Ion Trapping and Thermionic Emission across Sub-nm Pores.

Ionic transport through a graphene biomimetic subnanometer (sub-nm) pore of arbitrary shape and realistically decorated by intrinsic negatively charged sites is investigated by all-atom molecular dynamics (MD) simulations. In the presence of external electric fields, cation trapping-assisted translocation occurs in the vicinity of the 2D subnanometer pore, while the anion current is blocked by the negative charges. The adsorbed cations in such asymmetrically charged nanopores are located on the top of the nanopore instead of blocking the pore, as suggested previously in highly symmetric pores such as crown ethers. Our analysis of the different types of energy involved in ion translocations indicates that electrostatics is the dominant factor controlling ion transfer across these sub-nm pores. A physical model based on the thermionic emission formalism to account for the free energy barriers to ion flow reproduces the I-V characteristics.

Life cycle assessment of waste printed wiring board-derived Ag photocatalyst for sustainable fermentable sugar production.

An exploratory work involving waste printed wiring board (WPWB)-derived inexpensive silver oxide (Ag2O)-grafted silica-alumina composite photocatalyst (SAA) using quartz halogen and UVA irradiations (QHUV) (wavelength: 315 nm-1000 nm) has been revealed. The efficacy of the novel SAA photocatalyst was assessed in the synthesis of fermentable sugar (FS) by photo-hydrolysis of pure crystalline cellulose (PCC) in the QHUV-assisted batch reactor (QHUVBR), and the process parameters (5% AgNO3 doping, 7.5% catalyst concentration, 20 min PH time, and 80 °C PH temperature) were optimized using Taguchi orthogonal array design. The BET analysis of the optimal SAA catalyst possessed high surface area (27.24 m2/g), high pore volume, and pore diameter (0.042 cc/g and 13.1684 nm), respectively, whereas the XRD indicated the presence of significant crystalline phases of Ag2O. EDS mapping displayed the uniform distribution of silver active sites on silica-alumina support of the optimal SAA photocatalyst. The optimized parametric conditions in QHUVBR resulted in a maximum FS yield of 77.53% which was significantly higher compared to that achieved (34.52%) in a conventionally heated batch reactor (CHBR). Besides, the energy consumption was 75% more in CHBR (600 W) in comparison with QHUVBR (150 W), making the process energy-efficient and cost-effective. The environmental sustainability could be ascertained from the life cycle assessment (LCA) study in terms of low climate change, ionizing radiation, metal depletion, human toxicity, and other potential indicator values.

An image forensic technique based on JPEG ghosts.

The unprecedented growth in the easy availability of photo-editing tools has endangered the power of digital images. An image was supposed to be worth more than a thousand words, but now this can be said only if it can be authenticated or the integrity of the image can be proved to be intact. In this paper, we propose a digital image forensic technique for JPEG images. It can detect any forgery in the image if the forged portion called a ghost image is having a compression quality different from that of the cover image. It is based on resaving the JPEG image at different JPEG qualities, and the detection of the forged portion is maximum when it is saved at the same JPEG quality as the cover image. Also, we can precisely predict the JPEG quality of the cover image by analyzing the similarity using Structural Similarity Index Measure (SSIM) or the energy of the images. The first maxima in SSIM or the first minima in energy correspond to the cover image JPEG quality. We created a dataset for varying JPEG compression qualities of the ghost and the cover images and validated the scalability of the experimental results. We also, experimented with varied attack scenarios, e.g. high-quality ghost image embedded in low quality of cover image, low-quality ghost image embedded in high-quality of cover image, and ghost image and cover image both at the same quality. The proposed method is able to localize the tampered portions accurately even for forgeries as small as 10 × 10 sized pixel blocks. Our technique is also robust against other attack scenarios like copy-move forgery, inserting text into image, rescaling (zoom-out/zoom-in) ghost image and then pasting on cover image.

Life cycle sustainability assessment of optimized biodiesel production from used rice bran oil employing waste derived-hydroxyapatite supported vanadium catalyst.

The present work encompasses the production of biodiesel from an inexpensive waste, viz., used rice bran oil (URBO) through concurrent esterification and transesterification reactions employing the prepared waste duck bone (WDB)-derived natural hydroxyapatite (NAHAp) supported vanadium impregnated solid catalyst (VNAHAp). The optimal VNAHAp catalyst possessed 92.23 m2/g surface area which was much superior to 61.46 m2/g of the V-catalyst (VCHAp) prepared using commercially available hydroxyapatite (CHAp). The optimal (Box-Behnken design) concurrent trans/esterification reaction conditions for biodiesel (FAME) production from URBO and methanol were 5 wt.% catalyst concentration, 8:1 methanol/URBO mole ratio, and 35 wt% NH4VO3 loaded VNAHAp (35VNAHAp) catalyst that resulted in 99.05% FAME yield deploying a low-energy infrared radiator assisted batch reactor (LIRABR) which ensured significantly high FAME yield at milder temperature (60°C) and in shorter reaction time (30 min) compared to a conventionally heated batch reactor. The product biodiesel and its blend with commercial diesel conformed to ASTM D7467-10 specifications. The life cycle assessment (LCA) of the entire process advocated superior sustainability of the biodiesel production using 35VNAHAp catalyst in the LIRABR compared to their conventional counterparts. Valorization of two potential wastes, viz., URBO and WDB, under milder process conditions involving LIRABR and 35VNAHAp resulted in lower environmental impacts, thus rendering a sustainable biodiesel production process towards a greener earth.

E-waste derived silica-alumina for eco-friendly and inexpensive Mg-Al-Ti photocatalyst towards glycerol carbonate (electrolyte) synthesis: Process optimization and LCA.

Valorization ofe-waste, i.e. waste printed circuit board (WPCB) through mechano-chemical activation to obtain silica as the catalyst support and alumina as the catalyst precursor for eco-friendly synthesis of inexpensive highly proficient photocatalyst has been explored. The WPCB derived silica-supported layered double oxide photocatalyst (MATLSW) and its counterpart (MATLSC) involving commercial silica and alumina precursors were synthesized through the wet-impregnation method under energy-efficient solar simulated quartz halogen lamp (SSQHL) irradiations to improve its photocatalytic properties compared to conventional methods. The prepared MATLSWpossessed a significantly low band-gap-energy (1.58 eV) that rendered efficient photocatalysis in the green-synthesis of glycerol carbonate (GC) (an effective electrolyte). The catalytic performance of the optimal MATLSWresulted in a superior yield of GC (98.68%) compared to that rendered by MATLSCcatalyst (GC yield: 96.56%) at optimal process conditions. Detailed life cycle assessment (LCA) of the entire process (deploying Ecoinvent 3.5 database) dictated conducive environmental impacts concerning 1 kg GC synthesis alongside a scale-up study for 1 MT GC synthesis encompassing silica-alumina extraction from WPCB, MATLSW preparation, and employment of SSQHL-radiated batch reactor (SSQHLBR) (56.64% less energy consumption than conventional). The overall process deploying the novel MATLSWin conjunction with the effectual reactor demonstrated superiority over the conventional GC synthesis process through appreciable reductions of environmental impact parameters, namely GWP, FDP, and HTP by 5.78%, 3.60%, and 5.72% respectively. The developed green process for e-waste utilization can procreate an effective waste management protocol towards a cleaner world.

Functionalization of electronic, spin and optical properties of GeSe monolayer by substitutional doping: a first-principles study.

Substitutional doping has traditionally been used to modulate the existing properties of semiconductors and introduce new exciting properties, especially in two-dimensional materials. In this work, we have investigated the impact of substitutional doping (using group III, IV, V, and VI dopants) on the structural, electronic, spin, and optical properties of GeSe monolayer by using first-principles calculations based on density functional theory. Our calculated binding energies, formation energies and phonon dispersion curves of the doped systems support their stability and hence the feasibility of physical realization. Our results further suggest that switching between metallic and semiconducting states of GeSe monolayer can be controlled by dopant atoms with a different number of valence electrons. The band gap of the semiconducting structures can be tuned within a range of 0.2864 eV to 1.17 eV by substituting with different dopants. In addition, most of the doped structures maintain the low effective mass, 0.20m0to 0.59m0for electron and 0.21m0to 0.52m0for hole, which ensures the enhanced transport properties of GeSe based electronic devices. Moreover, when Ge is substituted with group V dopants, a magnetic moment is introduced in an otherwise non-magnetic GeSe monolayer. The optical absorption coefficient of the doped structures can be significantly improved (>2×) in the visible and infrared regions. These intriguing results would encourage the applications of doped GeSe monolayer in next-generation electronic, optoelectronic and spintronic devices.

Intensified wheat husk conversion employing energy-efficient hybrid electromagnetic radiations for production of fermentable sugar: process optimization and life cycle assessment.

This article reports an energy-efficient green pathway for the sustainable conversion of an abundant agro-residue viz. wheat husk (WH) into fermentable sugar (FS). The intensification effects of tungsten-halogen (TH) (150 W) and ultraviolet (UV) (100 W) irradiations on the pretreatment and subsequent hydrolysis of WH have been experimented with and optimized by Taguchi Orthogonal Design Array (TODA). In this study, two commercial catalysts, viz. Amberlyst-15 (A15) and nano-anataseTiO2 (NAT) have been used in varying concentrations for the WH conversion process in a novel TH-UV radiated rotating reactor (THUVRR). At optimized peracetic acid pretreatment conditions [90 °C reaction temperature; 1: 2.5 w/w of WH: H2O2; 1: 5 w/w of WH: CH3COOH (1 M); 2h of reaction time] maximum 20.2 wt. % FS yield and 15 wt. % isolated lignin (purity 97.6 %) were obtained. Subsequently, the pretreated WH (PWH) was hydrolyzed at optimized conditions [(700C reaction temperature; 7.5wt. % catalyst concentration (1:1 w/w A15: NAT); 1: 30 w/w of WH: water; 30 min reaction time)] in THUVRR to render maximum yield of FS (36.9g/ L) (67.4 wt. %), which was significantly greater than that obtained (20.2g/ L) (38.42 wt. %) employing a conventional thermal reactor (CTR). Besides, the energy consumption was 70% more in CTR (500 W) in comparison with THUVRR (150 W); thus, demonstrating markedly superior energy-efficiency vis-à-vis appreciable improvement in FS yield in THUVRR over CTR. Overall sustainability of the process analyzed by LCA proved the approach to be energy-saving and environmentally benign and is expected to be applicable to similar lignocellulosic agro-wastes.

Preservation of Aloe vera and soybean flour fortified Granny Smith apple through optimised quartz-halogen radiated vacuum drying: kinetics and quality evaluation.

BACKGROUND: Granny Smith (GS) apple has low protein content and poor antimicrobial properties; hence it has been blended with Aloe vera (AV; high ascorbic acid, antimicrobial and antioxidant properties) and soybean flour (SF; rich in phenols, flavonoids, ascorbic acid, total antioxidant and protein) in different proportions to obtain fortified GS, i.e. GSAVSF. Moreover, GS being a perishable fruit, its moisture content should be reduced to enhance shelf life. Accordingly, this GSAVSF was osmotically pre-dehydrated and finally dried through energy-efficient quartz-halogen radiation (QHR) assisted vacuum-drying (QHRVD) to produce dried GSAVSF i.e. (DGSAVSF) under optimized conditions. RESULTS: The optimally dehydrated DGSAVSF product resulted in minimum moisture (4.85% w/w) and maximum protein (6.24 g kg-1 ) content. The application of osmotic dehydration and QHRVD afforded acceptable colour of DGSAVSF compared to GSAVSF (ΔEI * = 10.07 ± 0.21). A parametric drying model was formulated that corroborated well with Fick's equation. QHRVD rendered high moisture diffusivity (1.49 × 10-8 m2 s-1 ) and low activation energy (27.64 kJ mol-1  K-1 ). Appreciable quality improvements with respect to fresh GS concerning ascorbic acid (176.05%), total phenolic (579.07%), total flavonoid (333.33%) contents and 2,2'-diphenyl-1-picrylhydrazyl radical scavenging activity (446.71%) could be achieved. The product demonstrated satisfactory shelf life (1 × 104 CFU g-1 : aerobic mesophilic; 1 × 104 CFU g-1 : mould and yeast) and high rehydration ratio (4.25 ± 0.1). CONCLUSION: The enrichment of GS with AV and SF along with optimal drying protocols could provide a quality fortified DGSAVSF through an energy-proficient sustainable process. The highly nutritious product with suitable colour, microbial stability and rehydration ratio also satisfied a 9-point hedonic scale, thus confirming consumer acceptability. © 2020 Society of Chemical Industry.

Printed Circuit Board-Derived Glass Fiber-Epoxy Resin-Supported Mo-Cu Bimetallic Catalyst for Glucose Synthesis.

A glass fiber-epoxy resin (GFER) framework derived from mixed waste printed circuit boards (MWPCBs) was utilized to prepare a cost-effective, reusable Mo-Cu bimetallic Bronsted-Lewis solid acid catalyst through wet-impregnation under near-infrared radiation (NIRR) activation. The efficacy of the novel Mo-Cu catalyst was assessed in the synthesis of glucose through hydrolysis of jute (Corchorus olitorius) fiber, and the process parameters were optimized (Mo precursor loading: 1.0 wt %, catalyst concentration: 5 wt %, hydrolysis temperature: 80 °C, and hydrolysis time: 10 min) through Taguchi orthogonal design. The GFER support and the prepared catalysts were characterized through thermogravimetric, X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Brunauer-Emmett-Teller (BET)-density functional theory, and TPD analyses. The optimal Mo-Cu catalyst and the GFER support possessed 45.377 and 7.049 m2/g BET area, 0.04408 and 0.02317 cc/g pore volume, 1.9334 and 0.7482 nm modal pore size, and surface acidity of 0.48 and 0.40 mmol NH3/g catalyst, respectively. X-ray photoelectron spectroscopy bands confirmed the coexistence of Mo6+ and Cu2+ species; XRD and FTIR analyses indicated the presence of MoO3 and CuO crystalline phases in all prepared catalysts. The optimal catalyst prepared through NIRR (wavelength 0.75-1.4 µm)-activated hydrothermal treatment resulted in a significantly greater glucose yield (75.84 mol %) than that achieved (53.64 mol %) using a conventionally prepared catalyst. Thus, an energy-efficient application of NIRR (100 W) could significantly improve catalytic properties over conventional hydrothermal treatment (500 W). The present investigation provides an innovative application of MWPCB-derived GFER as a promising cost-effective support for the preparation of highly efficient inexpensive solid catalysts for sustainable synthesis of glucose from low-cost waste jute fiber.

Effects of intermittent CO2 convection under far-infrared radiation on vacuum drying of pre-osmodehydrated watermelon.

BACKGROUND: Watermelon, a tropical seasonal fruit with high nutrient content, requires preservation through drying due to its perishable nature. Nevertheless, drying of watermelon through conventional processes has a negative impact either on the drying time or on the final product quality. In this work, osmotic dehydration of watermelon followed by far-infrared radiation-assisted vacuum drying (FIRRAVD) was optimized to develop dehydrated watermelon with minimum moisture content. Significantly, during FIRRAVD, an attempt was made to further intensify the drying rate by forced convection through intermittent CO2 injection. Drying kinetics of each operation and physicochemical qualities of dried products were evaluated. RESULTS: FIRRAVD was a viable method of watermelon drying with appreciably high moisture diffusivity (Deff,m ) of 4.97 × 10-10 to 1.49 × 10-9 m2 s-1 compared to conventional tray drying. Moreover, intermittent CO2 convection during FIRRAVD (ICFIRRAVD) resulted in appreciable intensification of drying rate, with enhanced Deff,m (9.93 × 10-10 to 1.99 × 10-9 m2 s-1 ). Significantly, ICFIRRAVD required less energy and approximately 16% less time compared to FIRRAVD. The quality of the final dehydrated watermelon was superior compared to conventional drying protocols. CONCLUSIONS: The novel CO2 convective drying of watermelon in the presence of far-infrared radiation demonstrated an energy-efficient and time-saving operation rendering a dehydrated watermelon with acceptable quality parameters. © 2017 Society of Chemical Industry.