Compact Morphology Research Articles

Vegetable filters reinforced with fibrillated cellulose for iron removal from water and organic white wines

This work presents an effective and practical alternative for iron removal in aqueous solutions and organic white wines based on continuous filtration via mechanically prepared filters composed of vegetable fibres from Scirpus californicus (Totora) and Gunnera tinctoria (Nalca) and fibrillated cellulose (CF) extracted from Eucalyptus globulus (Eucalipto). These filter materials were characterized by techniques such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). FT-IR signals confirmed that hydroxyl and carboxyl groups were present in the fibres; SEM micrographs showed a compact surface morphology among the three fibres studied; and TGA and DMA identified a thermal improvement and an increase in the compressive strength of the blend after the addition of CF. The effect of the amount of each fibre on iron retention in water and wine was evaluated, and the results showed that filters with 15% CF presented improved iron retention performance. Moreover, the iron retention capacities or efficiencies were 139.4 mg kg −1 and 57.3% in aqueous solution and 26% in white wine using the system composed of 21% GT, 64% SC and 15% CF. These results indicate the potential of these natural fibres in the demetallization of organic wines.

Effect of nitrogen content on structural and mechanical properties of AlTiZrTaHf(-N) high entropy films deposited by reactive magnetron sputtering

There is a growing interest in the design of high entropy alloys due to their remarkable properties and applications in various fields such as aerospace, medical and automotive. AlTiTaZrHf(-N) high entropy metal-sublattice nitrides were deposited in various argon‑nitrogen gas mixtures on glass and silicon substrates. X-ray diffraction analyses reveal a transition from amorphous to an FCC single phase by increasing the nitrogen content. The films have compact or columnar morphology depending on the nitrogen flow rate. Energy dispersive spectroscopy analysis shows a decreasing of the matals content as the nitrogen flow rates ratio R N2 = N 2 /Ar + N 2 increases. XPS surface analysis reveal the formation of nitrides when the nitrogen is introduced. Evolution of hardness and Young's modulus are discussed and the maximum values are obtained for a flow rates ratio R N2 of 10% at 27.67 GPa and 205.56 GPa respectively. The same film reveals good tribological properties compared to other films. This work conclusively demonstrates that high entropy metal-sublattice nitrides can be generated in an efficient way with tunable properties. • Multicomponent AlTiTaZrHf(-N) deposited by reactive magnetron sputtering • Effect of nitrogen content on microstructure, mechanical properties and tribological performance studied • H and E are monitored by controlling the stoichiometric of N/Me.

Polybenzimidazole membranes for vanadium redox flow batteries: Effect of sulfuric acid doping conditions

Polybenzimidazole (PBI) has been considered as promising membrane material for all-vanadium redox flow batteries (VRFBs) due to its compact morphology that can hinder vanadium crossover. However, its 2–4 mS cm−1 proton conductivity remains a challenge to achieve high energy efficiency. Recently developed PBI membranes showed conductivity up to 18 mS cm−1 by pre-treatment with phosphoric acid (PA) and up to 56 mS cm−1 with KOH. However, since the operation of VRFB uses sulfuric acid (SA), pre-treatment with different chemicals generates chemical wastes. Here we investigate the effects of pre-treaments with SA at various concentrations and temperatures. The optimized membrane (25C_10M, pretreated at 25 °C in 10M SA) increases its thickness during the treatment from 10 to 17 µm, and shows an improved conductivity in 2 M SA of 9.1 mS cm−1. In V4+ containing electrolyte, the area specific resistance was 262 mΩ cm2 , which is 3.3 and 1.7 times better than for 10 µm thick standard PBI (13 µm thick in 2 M SA) and 54 µm thick Nafion 212 membranes, respectively. The selectivity is 458x104 S min cm−3, 7, 30, and 29 times better than for PA, KOH pre-swelling, and Nafion 212 membranes, respectively. A VRFB performance test with a 17 µm thick 25C_10M PBI membrane showed an energy efficiency of 89.6% at 80 mA cm−2.

Design of SnO2:Ni,Ir Nanoparticulate Photoelectrodes for Efficient Photoelectrochemical Water Splitting.

Currently, hydrogen generation via photocatalytic water splitting using semiconductors is regarded as a simple environmental solution to energy challenges. This paper discusses the effects of the doping of noble metals, Ir (3.0 at.%) and Ni (1.5–4.5 at.%), on the structure, morphology, optical properties, and photoelectrochemical performance of sol-gel-produced SnO2 thin films. The incorporation of Ir and Ni influences the position of the peaks and the lattice characteristics of the tetragonal polycrystalline SnO2 films. The films have a homogeneous, compact, and crack-free nanoparticulate morphology. As the doping level is increased, the grain size shrinks, and the films have a high proclivity for forming Sn–OH bonds. The optical bandgap of the un-doped film is 3.5 eV, which fluctuates depending on the doping elements and their ratios to 2.7 eV for the 3.0% Ni-doped SnO2:Ir Photoelectrochemical (PEC) electrode. This electrode produces the highest photocurrent density (Jph = 46.38 mA/cm2) and PEC hydrogen production rate (52.22 mmol h−1cm−2 at −1V), with an Incident-Photon-to-Current Efficiency (IPCE% )of 17.43% at 307 nm. The applied bias photon-to-current efficiency (ABPE) of this electrode is 1.038% at −0.839 V, with an offset of 0.391% at 0 V and 307 nm. These are the highest reported values for SnO2-based PEC catalysts. The electrolyte type influences the Jph values of photoelectrodes in the order Jph(HCl) > Jph(NaOH) > Jph(Na2SO4). After 12 runs of reusability at −1 V, the optimized photoelectrode shows high stability and retains about 94.95% of its initial PEC performance, with a corrosion rate of 5.46 nm/year. This research provides a novel doping technique for the development of a highly active SnO2-based photoelectrocatalyst for solar light-driven hydrogen fuel generation.

Overcoming Nanoscale Inhomogeneities in Thin-Film Perovskites via Exceptional Post-annealing Grain Growth for Enhanced Photodetection.

Antisolvent-assisted spin coating has been widely used for fabricating metal halide perovskite films with smooth and compact morphology. However, localized nanoscale inhomogeneities exist in these films owing to rapid crystallization, undermining their overall optoelectronic performance. Here, we show that by relaxing the requirement for film smoothness, outstanding film quality can be obtained simply through a post-annealing grain growth process without passivation agents. The morphological changes, driven by a vaporized methylammonium chloride (MACl)–dimethylformamide (DMF) solution, lead to comprehensive defect elimination. Our nanoscale characterization visualizes the local defective clusters in the as-deposited film and their elimination following treatment, which couples with the observation of emissive grain boundaries and excellent inter- and intragrain optoelectronic uniformity in the polycrystalline film. Overcoming these performance-limiting inhomogeneities results in the enhancement of the photoresponse to low-light (<0.1 mW cm–2) illumination by up to 40-fold, yielding high-performance photodiodes with superior low-light detection.

Electrospun BiFeO3 Nanofibers for Vibrational Energy Harvesting Application

Bismuth ferrite (BiFeO3, BFO) has found application in a wide range of fields owing to its fascinating multiferroic properties. Herein, the interplay between the piezoelectric properties and morphology of BFO nanostructures is exploited for vibrational energy harvesting application by tailoring BFO to a high aspect ratio and high surface area nanofiber morphology. This work demonstrates a facile pathway for the fabrication of high‐performance flexible nanogenerators, based on BFO nanofibers, from a cost‐effective and energy‐efficient electrospinning technique. The X‐ray diffraction data of calcined fibers confirm the formation of noncentrosymmetric crystalline perovskite phase. The morphological characterization by scanning electron microscopy shows a compact anisotropic nanofibrous morphology. For the fabrication of nanogenerators, BFO nanofibers are embedded in a piezoactive polymer matrix (polyvinylidenfluoride [PVDF]). As‐fabricated BFO/PVDF composite nanogenerators produce a high peak‐to‐peak voltage output of 7.6 V, with an average output power density of 185 ± 106 nW cm−2 upon periodic application of force through finger knocking.

Structural and bioactive characteristics of a dextran produced by Lactobacillus kunkeei AK1

In this study, structural and techno-functional characteristics of an exopolysaccharide (EPS) produced by Lactobacillus kunkeei AK1 were determined. High-performance liquid chromatography (HPLC) analysis demonstrated that EPS AK1 was composed of only glucose units. 1H and 13C Nuclear magnetic resonance (NMR) analysis revealed that EPS AK1 was a dextran type EPS containing 4.78% (1 → 4)-linked α-d-glucose branches. The molecular weight of EPS AK1 was determined to be 45 kDa by Gel Permeation Chromatography (GPC) analysis. A high level of thermal stability up to 280 °C was determined for dextran AK1 detected by Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). Dextran AK1 appeared as regular spheres with compact morphology and as irregular particles in the solution with no clear cross-linking between the chains of the polysaccharide observed by Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) analysis, respectively. X-ray diffraction analysis (XRD) analysis demonstrated that dextran AK1 had a crystalline structure. A relatively strong antioxidant activity was observed for dextran AK1 determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging and cupric reducing antioxidant capacity (CUPRAC) tests. Finally, only a digestion ratio of 3.1% was observed for dextran AK1 following the in vitro simulated gastric digestion test.

Tribological Evaluation of Ferritic-Austenitic Stainless Steel Coatings with Different Percentages of Silver

Stainless steels have been evaluated in the form of coatings or thin films deposited using magnetron sputtering in various investigations. In most of these investigations, mainly the microstructural evaluation of this type of coating has been reported, while the evaluation of wear resistance has not been widely studied. In the present investigation, ferritic-austenitic stainless steel coatings with different percentages of silver were deposited by means of unbalanced DC magnetron sputtering. A stainless steel target doped with different numbers of silver inserts (0, 1, 2, 3, and 4 inserts) was used, obtaining coatings with silver percentages of up to 7.7 at. %, in order to evaluate their tribological properties. During the synthesis, the first layer of the bilayer was deposited with argon and the other in an atmosphere of argon and nitrogen. The structure of the coatings was evaluated by use of X-ray diffraction (XRD), and the morphology and the chemical composition were studied by means of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The hardness was tested through nanoindentation, and the wear test was carried out using the pin-on-disc technique. The wear tracks were evaluated via profilometry, SEM, and EDS. In general, the deposited films exhibited BCC and FCC phases and a compact morphology, as well as good adherence to the substrate. The results of the evaluation of the mechanical properties revealed an increase in the hardness of the coatings when the silver content was augmented, obtaining values of 9.8 GPa and 12.1 GPa for coatings with 0 and 4 silver inserts, respectively. Likewise, it was found that the wear resistance of coatings was higher, up to two orders of magnitude compared to the 316L stainless steel substrate. Finally, the wear rate of the multilayers decreased slightly with an increase in the percentage of silver in the films produced, up to an order of magnitude for the coating with 4 silver inserts relative to the coating with 0 silver inserts.

Production of low-Sn Cu-Sn Alloy Coatings onto Steel Substrate Using Sodium Citrate Bath – Part 1: the Effect of Current Mode (DC or SPC) and Applied Current on the Chemical, Morphological, and Anticorrosive Properties of the Coatings

Abstratc This work reports the production of low-tin Cu-Sn alloy coatings on carbon steel substrates using a bath containing CuCl2, SnCl2, and sodium citrate. In the first part of this study, the coatings were electrodeposited by direct and simple pulse current processes (DC and SPC, respectively). Different current density values were used, while the pulse frequency and duty cycle remained constant. Independent of the current mode used, low-tin Cu-Sn coatings, showing globular surface morphology and Cu6Sn5 as the main compositional phase, were produced. Both the current mode and the applied current density affected the anticorrosive properties of the coatings. The most protective DC and SPC coatings, showing Sn content < 3 wt.% and compact morphology, were prepared using j = 80 A m-2 and jc = 167 A m-2, respectively. High charge transfer resistance values were verified even after immersion for 24 h in 0.5 mol L-1 NaCl solution.

The GLEAMing of the first supermassive black holes: II. A new sample of high-redshift radio galaxy candidates

AbstractWhile unobscured and radio-quiet active galactic nuclei are regularly being found at redshifts$z &gt; 6$, their obscured and radio-loud counterparts remain elusive. We build upon our successful pilot study, presenting a new sample of low-frequency-selected candidate high-redshift radio galaxies (HzRGs) over a sky area 20 times larger. We have refined our selection technique, in which we select sources with curved radio spectra between 72–231 MHz from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. In combination with the requirements that our GLEAM-selected HzRG candidates have compact radio morphologies and be undetected in near-infrared$K_{\rm s}$-band imaging from the Visible and Infrared Survey Telescope for Astronomy Kilo-degree Infrared Galaxy (VIKING) survey, we find 51 new candidate HzRGs over a sky area of approximately$1200\ \mathrm{deg}^2$. Our sample also includes two sources from the pilot study: the second-most distant radio galaxy currently known, at$z=5.55$, with another source potentially at$z \sim 8$. We present our refined selection technique and analyse the properties of the sample. We model the broadband radio spectra between 74 MHz and 9 GHz by supplementing the GLEAM data with both publicly available data and new observations from the Australia Telescope Compact Array at 5.5 and 9 GHz. In addition, deep$K_{\rm s}$-band imaging from the High-Acuity WidefieldK-band Imager (HAWK-I) on the Very Large Telescope and from the SouthernHerschelAstrophysical Terahertz Large Area Survey Regions$K_{\rm s}$-band Survey (SHARKS) is presented for five sources. We discuss the prospects of finding very distant radio galaxies in our sample, potentially within the epoch of reionisation at$z \gtrsim 6.5$.

An electrodeposition model with surface relaxation predicts temperature and current effects in compact and dendritic film morphologies.

We study a thin-film electrodeposition model that represents the relaxation of the deposited material by adatom diffusion on quenched crystal topographies and considers simple mechanisms of cation flux in the electrolyte. The results of numerical simulations with collimated flux and a rapid cation reduction in contact with the deposit relate the surface roughness and the adatom hop numbers with two model parameters. A comparison with the results of a collective diffusion model for vapor deposition shows differences in the surface morphologies but similarities in scaling relations, which suggest thermally activated (Arrhenius) forms for the parameters of the electrodeposition model and relate one of them to the applied current. Simulations with purely diffusive cation flux and possible pore formation in simple cubic lattices show the growth of self-organized structures with leaf shapes (dendrites) above a compact layer that covers the flat electrode. The thickness of this layer and the average dendrite size also obey scaling relations in terms of the model parameters, which predict that both sizes decrease with the applied current, in agreement with recent experimental studies. Under all flux conditions, an increase in adatom diffusivity with temperature implies an increase in the average sizes of low-energy surface configurations, independently of their particular shapes. Finally, we note that a previously proposed model for electrodeposition produced similar morphologies, but the quantitative relations for the characteristic sizes differ from those of the present model, which also advances with a consistent interpretation of temperature effects.

Morphology quantification of three-dimensional fluid invasion patterns

In many situations, patterns of immiscible fluid displacement appear obviously different at first glance, but can hardly be distinguished using the commonly applied quantification by fractal dimension. In this work, we propose the mean finger area of the invading fluid, the average distance of defending fluid elements to the invading fluid as well as a discrete surface area of a coarse grained fluid representation as three alternative methods to characterize fluid displacement patterns in three dimensional permeable media. Applying the proposed methods to X-ray microtomography data of fluid displacement experiments in bead packs of homogeneous and mixed wettability, all of the three methods allow to clearly distinguish between a compact front morphology for wetting invading liquids and a finger-like structure for non-wetting invading liquids. When compared to the fractal dimension of the fluid pattern, all three quantities reveal more details with respect to the structure of the invading liquid. Applying these methods to microtomography data of fluid displacement in heterogeneously wetting bead packs reveal a fingering structure and preferential invasion paths that are controlled by local wettability.

Enhanced Photovoltaic Performance via a Bifunctional Additive in Tin-Based Perovskite Solar Cells

Tin-based perovskites with low toxicity and a narrow band gap have been promising candidates for the fabrication of efficient lead-free perovskite solar cells (PSCs). Nevertheless, the power conversion efficiency (PCE) of tin-based PSCs still lags behind that of their lead counterparts due to the poor film quality induced by uncontrollable crystal growth and Sn2+ self-doping. Herein, we introduce a bifunctional additive, ammonium thiocyanate (NH4SCN), into the precursor solution, which is able to coordinate with SnI2 to effectively control the crystal growth of the FASnI3 perovskite and further passivate the trap states in the perovskite films. Furthermore, the modified FASnI3 perovskite displays an improved film quality, featuring a compact surface morphology with an enlarged grain size, as well as decreased trap density, resulting in the reduction of the Sn4+/Sn2+ proportion in the film. As a result, a considerably enhanced PCE from 4.45 to 8.15% has been demonstrated. More importantly, the NH4SCN-based device exhibits advanced environment stability, retaining over 70% of the initial efficiency after 100 h of exposure to 35 ± 5% relative humidity at room temperature in a dark environment. This finding provides an additive strategy to improve the efficiency and stability of tin-based PSCs.

Texture evolution and corrosion behaviour of Sn–1.5 wt% Cr coatings containing Graphene oxide

ABSTRACT Sn–1.5 wt% Cr coating incorporated with varying quantity of Graphene oxide (GO) were deposited using electrodeposition technique on mild steel strip using aqueous electrolyte bath. The aqueous bath was dispersed with GO with increasing concentrations in mg/L (31.2, 62.5, 93.7, 125 and 156.2). All the coatings exhibited compact morphology and contained Sn and Cr-oxide phases (CrO2 and Cr2O3). Potentiodynamic polarisation and impedance spectroscopy techniques showed that the coating corrosion resistance increased for the initial addition of GO till Sn–Cr–GO2 coating (from 62.5 mg/L of GO) and it decreased thereafter for higher GO additions. The corrosion current density value exhibited by pristine Sn–Cr, Sn–Cr–GO2 and Sn–Cr–GO5 (from 156.2 mg/L of GO) was 1.38, 0.5 and 4.09 µA/cm2, respectively. Characterisation of the coating texture showed that between all the coatings, low angle grain boundary fraction was highest for Sn–Cr–GO2 coatings. The highest corrosion resistance was on account of special impermeable and inert properties of GO which was uniformly distributed in the coating matrix and the presence of a large fraction of low energy low angle grain boundaries. High corrosion rate in the case of Sn–Cr–GO5 coatings was attributed to the agglomeration of GO in the coating matrix which resulted in non-uniform coating morphology with high surface defects.

Comparative analysis of the effect of Ni, Mn, Fe and Si additives on the microstructure and phase composition of hypereutectic aluminum-calcium alloys

A comparative analysis of the phase composition and morphology of primary crystals in hypereutectic alloys of the Al–Ca–Ni–X system (where X is Fe, Si, Mn) was carried out by calculation and experimental methods, including the construction of liquidus surfaces. Additional alloying of the base Al–6%Ca–3%Ni alloy with iron and silicon leads to the formation of coarse elongated primary crystals up to 100 μm in length. It was found that the addition of manganese, on the contrary, leads to the formation of relatively small (average size about 20 μm) compact primary crystals of two four-component phases. Presumably, they are phases based on ternary compounds Al9CaNi and Al10CaMn2. The composition of eutectics in quaternary alloys has been determined. All aluminum-calcium eutectics are characterized by a higher proportion of the second phases, a thinner structure compared to the aluminum-silicon eutectic in AK18 silumin, and are also capable of spheroidization upon heating, starting from 500 °C. The combination of compact and spherical particle morphology after annealing in the 63-2Mn alloy appears to be favorable for deformation. Comparison of the manufacturability of the experimental alloy Al–8%Ca–1%Ni–2%Mn and the grade silumin AK18 showed the advantage of the former. In terms of the totality of its characteristics, the experimental alloy can be considered as the basis for the development of hypereutectic alloys of a new generation as an alternative to piston silumins of the AK18 type. The experimental alloy, the microstructure of which is characterized by a compact morphology and small size of primary crystals and a fine structure of the eutectic, in contrast to hypereutectic silumins, does not require special modification.

Improved opto-nonlinear and emission properties of spray pyrolysis grown Nd:PbS nanostructured thin films

Present work reported the development of PbS nanostructured thin films with different (0.0, 0.5, 1.5 and 2.5 wt %) novel Nd doping concentrations via spray pyrolysis method. Structural parameters of films were calculated from X-ray diffraction (XRD) patterns. Raman spectroscopy showed 131.73 cm−1 and 427.90 cm−1 characteristics vibrational mode of PbS. Grain shapes and size of films were analysed from SEM micrographs and showed compact morphology of films and well-covered substrate. The optical band gaps of films were found in order of 1.38–1.77 eV. Absorption index (k), refractive index (n), optical dielectric constant and optical conductivity were calculated and correlated with Nd doping concentrations. In addition, nonlinear optics of films also were examined as a function of Nd doping concentrations. The χ(3) and n2 values were found in order of ∼1.55 × 10−10-1.27 × 10−8 esu and 1.34 × 10−9-7.8 × 10−8 esu; respectively. Films possess better opto-nonlinear properties hence may be used in optoelectronics.

Experimental and first-principles simulation study on oxidation behavior at 1700 °C of Lu2O3–SiC-HfB2 ternary coating for SiC coated carbon/carbon composites

The oxidation behavior and microstructure evolution of Lu2O3–SiC-HfB2 ceramic coating specimen at 1700 °C were investigated systematically by experimental study and first-principles simulation. The prepared ternary coating possesses a compact morphology, which effectively defends C/C substrate against oxidation at 1700 °C for 130 h, showing a good antioxidant property. The formed HfSiO4, Lu2Si2O7, and HfO2 with high melting points play an active role in developing the thermal stability of the oxidized scale. Besides, Lu and Hf atoms incline to diffuse into SiO2, which enhances its structural stability. The improved thermal property of the oxidized scale for the Lu2O3–SiC-HfB2/SiC ceramic coating can delay the effective delivery of oxygen inwardly and thus prolong its oxidation protection time. The quick volatilization of SiO2 at 1700 °C induces that some glass phase evaporates with being not completely stabilized, which causes the formation of holes and the consumption of the inner coating.

Radio Morphology of Red Geysers

Abstract We present 150 MHz, 1.4 GHz, and 3 GHz radio imaging (LoTSS, FIRST, and VLASS) and spatially resolved ionized gas characteristics (SDSS IV-MaNGA) for 140 local (z &lt; 0.1) early-type red geyser galaxies. These galaxies have a low star formation activity (with a star formation rate, SFR, ∼ 0.01 M ⊙ yr−1), but show unique extended patterns in spatially resolved emission-line maps that have been interpreted as large-scale ionized winds driven by active galactic nuclei (AGN). In this work, we confirm that red geysers host low-luminosity radio sources (L 1.4GHz ∼ 1022 WHz −1). Out of 42 radio-detected red geysers, 32 are spatially resolved in LoTSS and FIRST, with radio sizes varying between ∼5–25 kpc. Three sources have radio sizes exceeding 40 kpc. A majority display a compact radio morphology and are consistent with either low-power compact radio sources (FR0 galaxies) or radio-quiet quasars. They may be powered by small-scale AGN-driven jets that remain unresolved at the current 5″ resolution of radio data. The extended radio sources, not belonging to the “compact” morphological class, exhibit steeper spectra with a median spectral index of −0.67, indicating the dominance of lobed components. The red geysers hosting extended radio sources also have the lowest specific SFRs, suggesting they either have a greater impact on the surrounding interstellar medium or are found in more massive halos on average. The degree of alignment of the ionized wind cone and the extended radio features are either 0° or 90°, indicating possible interaction between the interstellar medium and the central radio AGN.

Pectin-based active packaging: A critical review on preparation, physical properties and novel application in food preservation

Owing to increasing environmental concerns and growing demands for food quality maintenance, biodegradable active packaging is emerging on the market to overcome the challenges faced by traditional plastic packaging. Pectin, with characteristics of low price, non-toxic and good polymerization, is an ideal material for active food packaging. This review offers the current state of studies on pectin-based active packaging. Three different film formation methods were critically summarized. Physical properties of pectin-based packaging were systemically characterized regarding various pectin structural conformation. Furthermore, preservation behaviors and related mechanisms were fully illustrated to exhibit the outstanding advantages of pectin-based active packaging in food preservation. Pectin-based active packaging can be developed in either wet or dry processes. Wet process contains casting method leading to compact surface morphology and spraying method requiring specialized equipment, while dry process mainly refers to extrusion method with higher efficiency and meets the needs at commercial production. Physical properties of packaging including mechanical, hydrophobic and thermal characteristics are enhanced by modification of pectin conformation or incorporation with bio-polymers, overcoming the weaknesses of pure pectin packaging, such as thermal instability and strong hydrophilicity. After being functionalized with active compounds, pectin-based packaging with great antimicrobial, antioxidant and barrier properties is quite suitable for food preservation. Pectin-based packaging has great advantages to extend shelf-life of food by retarding lipid oxidation, inhibiting microbial growth, controlling water movement, etc. As a result, pectin-based active packaging with great physical and functional properties, has promising prospects in food preservation. • The main methods of pectin packaging preparation are casting, spraying and extrusion. • Film physical and functional properties are modified by incorporating other polymers. • Pectin active packaging can maintain quality and extend shelf-life of packaged food. • Pectin conformation exerts influences on film properties and preservation behaviors. • Pectin-based active packaging has a promising prospect in food packaging industry.

Prospects of using plastic chip electrodes at high current density: Recovery of zinc from acidic sulfate solutions

The prospects of using a polymer composite electrode the Plastic Chip Electrode (PCE) in high current applications has been reported in this manuscript. PCE is fabricated by a simple solution casting method from a semi-fluidic slurry. This semi-fluidic slurry forms a very compact composite, due to gravitational pull, during drying and hence yielding highly compact and pitless morphology. The viscosity of the polymer has been manipulated in such a way that it balances the weight of the graphite filler. This compact and highly dense morphology of the composite helps to sustain high currents. The electrowinning of zinc from the acidic solutions has been taken as a model for demonstration. The PCE has been found stable at a current density as high as 500 ​mA ​cm−2. The corrosion behavior of PCE has been evaluated. The current efficiency was found to be more than 90% in the presence of HER retardant additive, sodium lauryl sulfate (SLS). The deposited zinc metal has been characterized by various techniques.