Compact Surface Research Articles

Anti-classification results for weakly mixing diffeomorphisms

We extend anti-classification results in ergodic theory to the collection of weakly mixing systems by proving that the isomorphism relation as well as the Kakutani equivalence relation of weakly mixing invertible measure-preserving transformations are not Borel sets. This shows in a precise way that classification of weakly mixing systems up to isomorphism or Kakutani equivalence is impossible in terms of computable invariants, even with a very inclusive understanding of “computability”. We even obtain these anti-classification results for weakly mixing area-preserving smooth diffeomorphisms on compact surfaces admitting a non-trivial circle action as well as real-analytic diffeomorphisms on the 2-torus.

Infinitely many Riemann surfaces with a transitive action on the Weierstrass points

AbstractIn this short note, we prove the existence of infinitely many pairwise nonisomorphic, non‐hyperelliptic Riemann surfaces with automorphism group acting transitively on the Weierstrass points. We also find all compact Riemann surfaces with automorphism group acting transitively on the Weierstrass points, under the assumption that they are simple.

On the spaces of $(d + d^{c})$-harmonic forms and $(d + d^{\Lambda})$-harmonic forms on almost Hermitian manifolds and complex surfaces

In this paper, we study the spaces of (d+d^{c}) -harmonic forms and of (d+d^{\Lambda}) -harmonic forms, a natural generalization of the spaces of Bott–Chern harmonic forms (respectively, symplectic harmonic forms) from complex (respectively, symplectic) manifolds to almost Hermitian manifolds. We apply the same techniques to compact complex surfaces, computing their Bott–Chern and Aeppli numbers and their spaces of (d+d^{\Lambda}) -harmonic forms. We give several applications to compact quotients of Lie groups by a lattice.

Doodles and Blobs on a Ruled Page: Convex Quasi-envelops of Traversing Flows on Surfaces

AbstractLet A denote the cylinder $${\mathbb {R}} \times S^1$$ R × S 1 or the band $${\mathbb {R}} \times I$$ R × I , where I stands for the closed interval. We consider 2- of closed curves (“”) and compact surfaces (“”) in A, up to cobordisms that also are 2-moderate immersions in $$A \times [0, 1]$$ A × [ 0 , 1 ] of surfaces and solids. By definition, the 2-moderate immersions of curves and surfaces do not have tangencies of order $$\ge 3$$ ≥ 3 to the fibers of the obvious projections $$A \rightarrow S^1$$ A → S 1 , $$A \times [0, 1] \rightarrow S^1 \times [0, 1]$$ A × [ 0 , 1 ] → S 1 × [ 0 , 1 ] or $$A \rightarrow I$$ A → I , $$A \times [0, 1] \rightarrow I \times [0, 1]$$ A × [ 0 , 1 ] → I × [ 0 , 1 ] . These bordisms come in different flavors: in particular, we consider one flavor based on of doodles and blobs in A. We compute the bordisms of regular embeddings and construct many invariants that distinguish between the bordisms of immersions and embeddings. In the case of oriented doodles on $$A= {\mathbb {R}} \times I$$ A = R × I , our computations of 2-moderate immersion bordisms $$\textbf{OC}^{\textsf{imm}}_{\mathsf {moderate \le 2}}(A)$$ OC moderate ≤ 2 imm ( A ) are near complete: we show that they can be described by an exact sequence of abelian groups $$\begin{aligned} 0 \rightarrow {\textbf{K}} \rightarrow \textbf{OC}^{\textsf{imm}}_{\mathsf {moderate \le 2}}(A)\big /\textbf{OC}^{\textsf{emb}}_{\mathsf {moderate \le 2}}(A) {\mathop {\longrightarrow }\limits ^{{\mathcal {I}} \rho }} {\mathbb {Z}} \times {\mathbb {Z}} \rightarrow 0, \end{aligned}$$ 0 → K → OC moderate ≤ 2 imm ( A ) / OC moderate ≤ 2 emb ( A ) ⟶ I ρ Z × Z → 0 , where $$\textbf{OC}^{\textsf{emb}}_{\mathsf {moderate \le 2}}(A) \approx {\mathbb {Z}} \times {\mathbb {Z}}$$ OC moderate ≤ 2 emb ( A ) ≈ Z × Z , the epimorphism $${\mathcal {I}} \rho $$ I ρ counts different types of crossings of immersed doodles, and the kernel $${\textbf{K}}$$ K contains the group $$({\mathbb {Z}})^\infty $$ ( Z ) ∞ whose generators are described explicitly.

Heisenberg soft hair on Robinson-Trautman spacetimes

We study 4 dimensional (4d) gravitational waves (GWs) with compact wavefronts, generalizing Robinson-Trautman (RT) solutions in Einstein gravity with an arbitrary cosmological constant. We construct the most general solution of the GWs in the presence of a causal, timelike, or null boundary when the usual tensor modes are turned off. Our solution space besides the shape and topology of the wavefront which is a generic compact, smooth, and orientable 2d surface Σ, is specified by a vector over Σ satisfying the conformal Killing equation and two scalars that are arbitrary functions over the causal boundary, the boundary modes (soft hair). We work out the symplectic form over the solution space using covariant phase space formalism and analyze the boundary symmetries and charges. The algebra of surface charges is a Heisenberg algebra. Only the overall size of the compact wavefront and not the details of its shape appears in the boundary symplectic form and is canonical conjugate to the overall mass of the GW. Hence, the information about the shape of the wavefront can’t be probed by the boundary observer. We construct a boundary energy-momentum tensor and a boundary current, whose conservation yields the RT equation for both asymptotically AdS and flat spacetimes. The latter provides a hydrodynamic description for our RT solutions.

Performance of Sustainable Green Concrete Incorporating Quarry Dust and Ferronickel Slag as Fine Aggregate.

This paper presents a study on the combined use of two by-products, namely quarry dust (QD) and ferronickel slag (FNS), as a full substitute for natural sand to improve the greenness of concrete production. Quarry dust was used in increments of 25% to a maximum of 75% substitution, where nickel slag was used as the remaining proportion of fine aggregate. All the combinations of quarry dust and nickel slag were found to be compliant with AS 2758.1 and they showed notably better grading than 100% sand. In this research, standard concrete tests, such as the slump test for fresh concrete, and compression, tensile and shrinkage tests for hardened concrete, were conducted. Scanning electron microscopy and X-ray diffraction analysis were also conducted for microstructural investigation. The results concluded that the combinations of quarry dust and nickel slag in concrete as a whole substitution of sand provide similar results for these properties. Specifically, 25% quarry dust with 75% nickel slag proved to be the most promising alternative to sand, with compressive and splitting tensile strengths of 62 and 4.29 MPa, respectively, which were 16% and 20% higher than those of the control mix. Also, lower drying shrinkage was observed for this combination compared to the control mix. The higher strength is attributed to the rough texture and angular shape of both quarry dust and nickel slag providing a better mechanical interlocking. The validity of this result has also been confirmed through image analysis of micrographs from various specimens. In microstructural investigations, specimens with QD and FNS exhibited fewer voids and a more compact surface compared to the control specimen. This shows the potential for further research into the use of quarry dust and nickel slag in the production of green concrete.

Solid phase speciation controls copper mobilisation from marine sediments by methanobactin

Although marine environments represent huge reservoirs of the potent greenhouse gas methane, they currently contribute little to global net methane emissions. Most of the methane is oxidized by methanotrophs, minimizing escape to the atmosphere. Aerobic methanotrophs oxidize methane mostly via the copper (Cu)-bearing enzyme particulate methane monooxygenase (pMMO). Therefore, aerobic methane oxidation depends on sufficient Cu acquisition by methanotrophs. Because they require both oxygen and methane, aerobic methanotrophs reside at oxic-anoxic interfaces, often close to sulphidic zones where Cu bioavailability can be limited by poorly soluble Cu sulphide mineral phases. Under Cu-limiting conditions, certain aerobic methanotrophs exude Cu-binding ligands termed chalkophores, such as methanobactin (mb) exuded by Methylosinus trichosporium OB3b. Our main objective was to establish whether chalkophores can mobilise Cu from Cu sulphide-bearing marine sediments to enhance Cu bioavailability.Through a series of kinetic batch experiments, we investigated Cu mobilisation by mb from a set of well-characterized sulphidic marine sediments differing in sediment properties, including Cu content and phase distribution. Characterization of solid-phase Cu speciation included X-ray absorption spectroscopy and a targeted sequential extraction. Furthermore, in batch experiments, we investigated to what extent adsorption of metal-free mb and Cu-mb complexes to marine sediments constrains Cu mobilisation.Our results are the first to show that both solid phase Cu speciation and chalkophore adsorption can constrain methanotrophic Cu acquisition from marine sediments. Only for certain sediments did mb addition enhance dissolved Cu concentrations. Cu mobilisation by mb was not correlated to the total Cu content of the sediment, but was controlled by solid-phase Cu speciation. Cu was only mobilised from sediments containing a mono-Cu-sulphide (CuSx) phase. We also show that mb adsorption to sediments limits Cu acquisition by mb to less compact (surface) sediments. Therefore, in sulphidic sediments, mb-mediated Cu acquisition is presumably constrained to surface-sediment interfaces containing mono-Cu-sulphide phases.

Growth mechanism and the properties of CIGS thin films for zero bias photodetector devices

CuInGaSe2 quaternary thin films have been deposited using a single-source, single-step thermal evaporation technique using hydrothermally fabricated CIGS powder. Highly crystalline, homogeneous, and stoichiometric CIGS powder source was prepared by a hydrothermal method and then evaporated at substrate temperatures of room temperature, 150°C, and 300°C. The bulk and surface structural, morphological, and optical properties of the samples were analyzed. The sample deposited at room temperature did not show any phase formation; however, increasing the substrate temperature resulted in the formation of binary and quaternary phases due to interdiffusion of the species. XPS and Raman spectra analysis revealed nanocrystalline Cu2Se phase formation at the interface, while the bulk of the sample remained single-phase CIGS. A higher deposition temperature also facilitated larger grain size and a more compact surface morphology. Increasing the substrate temperature increased the likelihood of interdiffusion of the species from the evaporation flux and controlled the bulk and surface properties of the samples. CIGS/CdS active photodetectors were fabricated by deposition of a CdS buffer layer, with the sample deposited at 150°C showing the highest photocurrent along with low response and recovery times at 0 V bias.

Thurston’s asymmetric metric on the space of singular flat metrics with a fixed quadrangulation

Consider a compact surface equipped with a fixed quadrangulation. One may identify each quadrangle on the surface with a Euclidean rectangle to obtain a singular flat metric on the surface with conical singularities. We call such a singular flat metric a rectangular structure. We study a metric on the space of unit area rectangular structures which is analogous to Thurston’s asymmetric metric on the Teichmüller space of a surface of finite type. We prove that the distance between two rectangular structures is equal to the logarithm of the maximum of ratios of edges of these rectangular structures. We give a sufficient condition for a path between two points of the this Teichmüller space to be geodesic and we prove that any two points of this space can be joined by a geodesic. We also prove that this metric is Finsler and give a formula for the infinitesimal weak norm on the tangent space of each point. We identify the space of unit area rectangular structures with a submanifold of a Euclidean space and we show that the subspace topology and the topology induced by the metric we introduced coincide. We show that the space of unit area rectangular structures on a surface with a fixed quadrangulation is in general not complete.

Fabrication of CZTS Thin Film on Flexible Cu-Foil Substrate by Two-Stage Process

In this research, CZTS thin films grown on flexible Cu-foil with varying sulfurization times. Various characterization methods were employed, including X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), optical transmission, and photoluminescence (PL) measurements. Distinctive diffraction peaks characteristic of the kesterite CZTS phase were observed in the XRD analysis, occurring around at 2θ= 28.45° (112), 47° (220/204), and 56° (312/116). Additionally, some secondary phases such as Cu2S and SnS were identified. Raman spectroscopy confirmed the presence of the kesterite phase, with a prominent peak detected at approximately ~336 cm-1, attributed to sulfur atom vibrations within the kesterite structure. Apart from CZTS structure, minor peaks suggesting the presence of the Cu2SnS3 (CTS) phase was detected. EDX analysis revealed compositions with Cu-poor content and Zn-rich content across all samples, with slight variations in sulfurization dwell times affecting the chemical composition. SEM imaging at different magnifications showed alterations in surface morphology and grain structures. Films sulfurized for 30 s and 60 s displayed a granular structure morphology, while extending the dwell time to 120 s resulted in a more compact surface morphology. Optical band gap values ranged between 1.57 and 1.60 eV. PL measurements consistently exhibited strong PL emission around 1.25 eV for all samples, attributed to various transitions within the CZTS structure. The absence of observable band-to-band transitions in the PL measurements indicated the presence of intrinsic defect levels and recombination centers within CZTS. Overall, it was demonstrated in this study that CZTS thin films can be produced on flexible Cu-foils with short sulfurization times, thereby expanding the application areas of CZTS thin-film solar cells.

Design and commissioning of a versatile surface ion source

A compact and versatile ion source was designed and commissioned to be used with the new low energy ion beam facilities at TRIUMF. The ion source is based on the principle of surface ionization, in which ions are generated from a neutral atom by impact with a solid surface. The design of the ion source considered several factors, including the type of ions, intensity, energy and emittance of the extracted beams from the source. Commercially available alkali materials with an ionizer are used in the source; the ionizer is integrated with the in house design of extraction and transport system. The source performance was characterized using diagnostics techniques, and its key parameters, such as beam current, emittance, and beam species, were measured. The results showed that the compact surface ion source is able to achieve high ionization efficiency and stable operation, and is suitable for use in commissioning and operation of various ion beam facilities in particle accelerator laboratories.

Physico-chemical, functional, pasting and structural characteristics of two malted maize flours produce under optimal conditions

Maize is a popular gluten-free grain, used in many dishes in Africa and elsewhere. It provides numerous nutrients (especially starch) and contains antinutritional factors (phytates). To reduce these factors and improve the nutritional and physical potential of maize, a number of treatments are required, including malting. This study therefore investigated the physicochemical, functional, structural, and pasting properties of two malted maize varieties (Atp-Y and Coca-sr) produce under optimal conditions. After receiving the two maize varieties from the Agricultural Research Institute for development, the Atp-Y variety was soaked for 30 h at 18.66 °C with 0.37% plant salt, followed by germination at 30 °C for 218.58 h and a ripening period of 40 h, while the Coca-sr variety was soaked for 3.90 h at 20.57 °C with 0.0219% plant salt, followed by germination at 30 °C for 251.55 h and a ripening period of 58.73 h. The flours obtained were subjected to physicochemical, structural, pasting and functional analysis. These analyses showed that the protein, fibre, ash, carbohydrate, starch and energy density content were significantly influenced by the variety. The Atp-Y variety had the highest contents of Ca (855.00 mg/100 g), Na (125.36 mg/100 g) and Cu (0.53 mg/100 g). The availability of Ca, Na and divalent cations was significantly higher in the Atp-Y variety. The Coca-sr variety contributed the most to achieving the protein (40.02 to 73.88%) and lipid (27.30 to 38.08%) requirements of children aged 0 to 59 months. The contents of phytates, cyanides and condensed tannins were similar in both varieties, while oxalates (7.88 mg/100 g), trypsin inhibitors (2.07 mg/100 g) and hydrolyzed tannins (15.02 mg EC/g) were more abundant in the Coca-sr variety. Phenols, flavonoids and saponins ranged between 45.96 and 68.39 mg GAE/g, 32.13 and 39.27 mg CE/g and 0.45 mg/100 g, respectively. No significant differences were found in the physical and functional properties, although the Atp-Y variety had a higher water retention and swelling capacity. Malting variety and conditions had no significant effect on Pasting Time, Setback, Setback ratio and Stability ratio in contrast to Pasting Temperature, Peak viscosity, Holding viscosity, Breakdown and Final viscosity. The Atp-Y grade exhibited the highest pasting parameters when pasting temperature was excluded. Scanning electron microscopy showed that the microscopic structure varied from one variety to another, although the grains had similar sizes. The Microscopic dispersions of grains testifies to the enzymatic activity in the Coca-sr variety, the compact surface layer with protruding grains testifies to the fiber richness of the Atp-Y variety. The grain distribution of the particles showed that more than 50% of the grains in both types were 400 µm in size. X-ray diffraction (XRD) showed that the degradation of the crystalline structure of the starch depended on the variety and the physiological phenomena taking place there. These results clearly show that these flours are well suited for the formulation of foods with high energy and nutritional value. However, they could also be used as sweeteners in panification or as raw materials in the brewing industry.

Vibrationally driven particle formations in fluid systems with bimodal thermal inhomogeneities

This study builds on and extends an earlier investigation [Santhosh and Lappa, “On the relationship between solid particle attractors and thermal inhomogeneities in vibrationally-driven fluid-particle systems,” Phys. Fluids 35(10), 103316 (2023)]. As the predecessor work, it can be placed in a wider theoretical context, that is, a line of inquiry started a decade ago [Lappa, “The patterning behavior and accumulation of spherical particles in a vibrated non-isothermal liquid,” Phys. Fluids 26(9), 093301 (2014)] about the surprising ability of high-frequency vibrations imposed on a non-isothermal fluid containing dispersed solid particles to support the self-emergence of ordered particle structures. Here, the non-trivial relationship between the number and shape of the particle formations and the nature of the thermal conditions along the boundary of the fluid container is further explored by probing in detail the role of thermal spot multiplicity. The problem is approached in the framework of a hybrid Eulerian–Lagrangian numerical approach. The results indicate that completely new morphologies become accessible, which are not possible when only two walls are thermally active. Moreover, on increasing the angle ϕ formed by vibrations with the direction perpendicular to the adiabatic walls of the cavity, the compact surfaces formed by particles for ϕ = 0° are taken over by more complex formations, which give the observer the illusion of a flexible fabric formed by the intersection of many independent filamentary structures.

Effect of Soybean Oil on the Improvement of the Functionality of Edible Membrane-Type Food Packaging Films Based on Caseinate-Carboxymethyl Chitosan Compositions.

Edible film biopolymers are gaining attention to tackle problems of plastic waste and food safety to alleviate environmental problems associated with plastic products in food packaging. In this study, caseinate-carboxymethyl chitosan (CA-CMCH) composite films were made with the incorporation of soybean oil (SO) using a casting technique. The influence of different soybean oil concentrations at 0, 0.5, and 1% (w/w) on physical, mechanical, barrier, and surface characteristics of films composed of caseinate-carboxymethyl chitosan (CA-CMCH) was evaluated. The brightest film (L* value of 95.95 ± 0.30) was obtained with the edible film made from the control group of samples with sodium caseinate (NaCA-100; 100% NaCA). The results also indicated that samples with 1% SO in NaCA-75 and CaCA-75 had lower water vapor permeability (WVP), while those with NaCA-50 and CaCA-50 showed higher values of WVP. For mechanical properties, this study found that incorporating soybean oil into the caseinate-carboxymethyl (CA-CMCH) composite films led to an enhancement of both tensile strength and elongation at break. The morphological structures, determined using SEM, of control and composite films showed compact and homogenous surfaces. Overall, the addition of soybean oil contributed to the improvement of the functional properties of the edible films, offering potential solutions to the environmental issues associated with plastic packaging and enhancing the safety and performance of food packaging.

Influence of suspended particles and dissolved organic matters on virus enrichment in reclaimed water by two-step tangential flow ultrafiltration: Phenomena and mechanisms

Enteric virus concentration in large-volume water samples is crucial for detection and essential for assessing water safety. Certain dissolution and suspension components can affect the enrichment process. In this study, tangential flow ultrafiltration (TFUF) was used as an enrichment method for recovering enteric virus in water samples. Interestingly, the bacteriophage MS2 recovery in reclaimed water and the reclaimed water without particles were higher than that in ultrapure water. The simulated reclaimed water experiments showed that humic acid (HA) (92.16% ± 4.32%) and tryptophan (Try) (81.50 ± 7.71%) enhanced MS2 recovery, while the presence of kaolin (Kaolin) inhibited MS2 recovery with an efficiency of 63.13% ± 11.17%. Furthermore, Atomic force microscopy (AFM) revealed that the MS2-HA cluster and the MS2-Try cluster had larger roughness values on the membrane surface, making it difficult to be eluted, whereas MS2-Kaolin cluster had compact surfaces making it difficult to be eluted. Additionally, the MS2-HA cluster is bound to the membrane by single hydrogen bond with SO, whereas both the MS2-Try cluster and the MS2-Kaolin cluster are bound to the membrane by two hydrogen bonds, making eluting MS2 challenging. These findings have potential implications for validating standardized methods for virus enrichment in water samples.

Particle size-dependent anti-corrosion and mechanical behavior of green-graphene composite

In this study, Green graphene (GG) was synthesized from residual agricultural biomass through pyrolysis and prepared various sizes (2D, 37 μm, 45 μm, 53 μm, and 100 μm) via mechanical and liquid phase exfoliation. These GG samples were incorporated into an EP matrix, forming GG/EP composite coatings for carbon steel. Corrosion resistance was assessed via PDP and EIS techniques. The 37 μm-GG/EP composite coating also showed uniform distribution and compact surfaces. The 37 μm-GG/EP composite coating displayed higher corrosion inhibition (99 %) owing to the even distribution of GG within the EP matrix than the uncoated, along with enhanced hydrophobicity, tensile strength (61.3 %), fracture strain (77.2 %), and toughness (90.5 %) than pure EP coating. Improved corrosion resistance, which was found related to three main factors: first, GGs enhance the coating integrity by obstructing pores and flaws, to stop corrosive media from penetrating. Second, the well-dispersed GG sheet lengthens the diffusion pathways for corrosive agents to the carbon steel substrate, consequently lenghtening the corrosion process. Third, at 37 μm size the resititve forcefields of the GG/EP structure become the most effecitve agaisnt the corrosive media. The study also establishes GG as an eco-friendly sustainable alternative of non-renewable resource based mined compounds of Zn, etc. that are universally and traditionally used, for protective coatings.

Solving the cohomological equation for locally Hamiltonian flows, part I - local obstructions

We study the cohomological equation Xu=f for smooth locally Hamiltonian flows on compact surfaces. The main novelty of the proposed approach is that it is used to study the regularity of the solution u when the flow has saddle loops, which has not been systematically studied before. Then we need to limit the flow to its minimal components. We show the existence and (optimal) regularity of solutions regarding the relations with the associated cohomological equations for interval exchange transformations (IETs). Our main theorems state that the regularity of solutions depends not only on the vanishing of the so-called Forni's distributions (cf. [9,11]), but also on the vanishing of families of new invariant distributions (local obstructions) reflecting the behavior of f around the saddles. Our main results provide some key ingredient for the complete solution to the regularity problem of solutions (in cohomological equations) for a.a. locally Hamiltonian flows (with or without saddle loops) to be shown in [15].The main contribution of this article is to define the aforementioned new families of invariant distributions dσ,jk, Cσ,lk and analyze their effect on the regularity of u and on the regularity of the associated cohomological equations for IETs. To prove this new phenomenon, we further develop local analysis of f near degenerate singularities inspired by tools from [14] and [17]. We develop new tools of handling functions whose higher derivatives have polynomial singularities over IETs.

Design of dual carbon encapsulated porous micron silicon composite with compact surface for enhanced reaction kinetics of lithium-ion battery anodes

Developing high-performance composites with fast charging and superior cycle life is paramount for lithium-ion batteries (LIBs). Herein, we synthesized a double-shell carbon-coated porous structure composite with a compact surface (P-Si@rGO@C) using low-cost commercial micron-sized silicon (Si) instead of nanoscale silicon. Results reveal that the unique P-Si@rGO@C features high adaptability to volume expansion, accelerates electron/ion transmission rate, and forms a stable solid electrolyte interphase (SEI) film. This phenomenon arises from the synergistic effect of abundant internal voids and an external double-layer carbon shell with a dense surface. Specifically, the P-Si@rGO@C anode exhibits a high initial coulombic efficiency (ICE) (88.0 %), impressive rate-capability (612.1 mAh/g at 2C), and exceptional long-term cyclability (972.2 mAh/g over 500 cycles at 0.5C). Further kinetic studies elucidate the diffusion-capacitance hybrid energy storage mechanism and reveal an improved Li+ diffusion coefficient (from 3.47 × 10-11 to 2.85 × 10-9 cm2 s-1). Ex-situ characterization confirms the crystal phase change of micron-sized Si and the formation of a stable LiF-rich SEI. Theoretical calculations support these findings by demonstrating an enhancement in the adsorption ability of Si to Li+ (from -0.89 to -0.97 eV) and a reduction in the energy migration barrier (from 0.35 to 0.18 eV). Additionally, practical LixSi powder is shown to increase the ICE of full cells from 67.4 % to 87.9 %. Furthermore, a pouch cell utilizing the prelithiated P-Si@rGO@C anode paired with LiNi1/3Co1/3Mn1/3O2 (NCM111) cathode delivers a high initial reversible capacity of 7.2 mAh and 76.8 % capacity retention after 100 cycles. This work provides insights into the application of commercial silicon-aluminum alloy powder in the anode of high-energy LIBs.

THIN LIGNOCELLULOSIC LINERS BASED OF SPRUCE SHAVINGS

The article is devoted to determining the basic physical and mechanical properties of sheet materials up to 1.5 mm thick based on wood shavings and PVAc glue with a high proportion of water, pressed under high pressure up to 25 MPa and a temperature of around 190°C, so that the softening of lignin caused by the generated steam, allow to create a compact and non-crumbling surface. In order to characterize the physical-mechanical properties of the new wood-based sheet material with minimum thickness and characteristic elasticity, tests according to the CEPI (Confederation of European Paper Industries) standards were adopted. Procedures for tensile strength according to ISO 1924-2 (2008), Burst strength according to ISO 2758 (2014), puncture according to ASTM D781-68 (1973), water absorption according to ISO 5637 (1989) and porosity according to TAPPI Test method T460 were applied.

Aloe vera Gel–Reinforced Biodegradable Starch–PVA Blends for Sustainable Packaging of Green Chillies

ABSTRACTThe objective of the current study was to evaluate the feasibility of Aloe vera gel as a plasticizer and crosslinker in improving the properties of starch–polyvinyl alcohol blends that could find applications in packaging. The concentration of Aloe vera gel was varied (1%, 3%, 5% and 7% wt/wt) to produce SPA‐1, SPA‐3, SPA‐5 and SPA‐7 films, respectively. The plasticizing and crosslinking characteristics associated with Aloe vera gel had a positive influence on the mechanical properties of the films. Addition of Aloe vera gel increased the tensile strength of films from 27.45 MPa (control) to 32.98, 32.53 and 32.32, for SPA‐1, SPA‐3 and SPA‐5 films, respectively. Among all the films, highest elongation at break (20.62%) was observed for SPA‐3 films. Due to crosslinking, degree of swelling, water solubility and water vapour permeability for SPA‐3 films decreased by 5.58%, 38.29% and 21.44%, respectively, compared to control films. The contact angle of the SPA‐3 film significantly increased by 49.25% when compared to control samples. Scanning electron microscope images revealed compact and smooth surface microstructure of control films, and crosslinking was evident in presence of Aloe vera gel. The rate of degradation for SPA‐3 films in soil after 40 days was enhanced by 32.25% compared to control films. SPA‐1 and SPA‐3 films were tested for use as packaging material for storage of green chillies. Chillies under unpacked conditions, in control and SPA‐1 films, turned red in 3 days. Those stored in films with 3% Aloe vera gel began to change colour later (after 5 days) with no visual evidence of microbial or fungal growth. In summary, starch–polyvinyl alcohol matrix films with 3% Aloe vera gel (SPA‐3) were effective as a sustainable alternative in increasing shelf life of foodstuff.