Surface Morphology Research Articles

Comparative study on dehydration of isopropanol and acetonitrile by pervaporation using PEBA/PANI/zeolite mixed matrix membranes

ABSTRACT Isopropanol (IPA) and Acetonitrile (ACN) solvents form azeotrope with water and separation by conventional processes is energy intensive. So, Pervaporation (PV) process became quite prominent and an alternative technique for dehydration of azeotropic mixtures. The selection of membrane places a crucial role in pervaporative separation and Mixed Matrix Membranes (MMMs) were widely employed. In this context, MMMs designated as PEBA-PANI and PEBA-PANI-4A were prepared by embedding PANI, zeolite 4A fillers in PEBA matrix. The synthesised zeolite particles, pristine PEBA and MMMs were characterised by XRD, FTIR, as well as contact angle measurements. Further, surface morphology and average particle size of zeolite particles are observed using SEM. Sorption studies with varying composition of isopropanol, and acetonitrile aqueous mixtures were correlated with their PV performances. The PEBA-PANI-4A MMMs showed higher % sorption of 11.34 and 8.57 for IPA–Water and ACN–Water systems respectively. Similarly greater pervaporation flux and selectivity of 0.28 kg/m2h and 720 were obtained for IPA–Water and 0.068 kg/m2h and 564 for ACN–Water systems at 10 wt. % water concentration. The PV results revealed that the MMMs exhibited better performance than pristine PEBA. All three membranes showed greater sorption, flux and selectivity for IPA-Water system than ACN-Water system.

Geometrical incompatibility regulated pattern selection and morphological evolution in growing spherical soft tissues

Surface morphological patterns are widely observed in natural systems, which are closely correlated to vital biological functions and inspire surface morphology designs in soft matter systems. Geometrical incompatibility widely exists in biological tissues across different length scales and plays an important role in growth-induced pattern selection and morphological evolution of soft tissues. However, the underlying physical mechanism of growth-induced pattern formation and post-buckling evolution in geometrically incompatible spherical soft tissues remain elusive. Here, the effect of geometrical incompatibility on the growth-induced pattern selection and post-buckling evolution are investigated through swelling experiment, theoretical analysis and numerical simulation. The results show that not only the instability pattern but also the instability threshold can be regulated by manipulating geometric incompatibility. Notably, when the geometrical incompatibility parameter exceeds a critical value, spontaneous instability is observed before growth. With continuous growth, the core–shell soft sphere buckles into a periodic buckyball pattern and evolves toward a bean-shaped pattern, and then undergoes a wrinkle-to-fold transition into a labyrinth topography. Our results demonstrate, both experimentally and theoretically, that geometrical incompatibility can guide the growth-induced pattern formation and morphological evolution effectively. This study not only enhances our understanding of the growth-induced pattern selection and morphological evolution in spherical soft tissues, but also provides an inspiring insight for the fabrication of morphological patterns on curved surfaces.

Characterization, mechanical, corrosion, and in vitro apatite-formation ability properties of hydroxyapatite-reduced graphene oxide coatings on Ti6Al4V alloy by plasma electrolytic oxidation

Hydroxyapatite-reduced graphene oxide (HA/rGO) nanocomposite coatings were developed on Ti6Al4V alloy using plasma electrolytic oxidation (PEO). The PEO electrolyte comprised calcium acetate (C4H6CaO4) and calcium glycerophosphate (C3H7O5CaP). Prior to integrating reduced graphene oxide into the coating solution, parameters such as voltage and current density were optimized using scanning electron microscopy (SEM). The influence of various current densities and graphene concentrations on coating properties was analyzed. Coating phase structures, surface morphologies, functional groups, and chemical compositions were characterized by X-ray diffraction (XRD), SEM, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and energy dispersive spectroscopy (EDS). Raman spectroscopy confirmed the presence of graphene in the coatings. Surface morphology examinations revealed that surface cracks appeared at voltages above 350 V due to thermal stresses. Increasing current density reduced the number of porosities but increased pore size. Adding graphene to the solution to form HA/rGO coatings further decreased both the number and size of porosities. XRD analysis identified phases of titanium, anatase, rutile, titanium phosphide, tri-calcium phosphate (TCP), and hydroxyapatite in the coatings. Corrosion properties were assessed via potentiodynamic polarization tests in simulated body fluid (SBF) solution. Tribological and mechanical properties were evaluated by pin-on-disk and microhardness, respectively. The in vitro apatite-formation ability of the coatings was assessed by immersion in SBF at 37 °C, with ion concentration changes measured by inductively coupled plasma spectrometry (ICP). Results indicated that increasing current density reduced porosities and increased the Ca/P ratio.

Bamboo durability: Understanding the combined effect of weathering and mildew infection

Bamboo has been widely used in outdoor applications and heat treatment is a typical industrial technique for improving its durability. Weathering and mildew are the two main types of deterioration that occur on bamboo. However, there are few studies on the deterioration of bamboo properties and degradation mechanism under such combined effect. Therefore, in this study, the effect of weathering on the mildew infection value (MIV) of natural bamboo (NB) and heat-treated bamboo (HB) were compared. The changes in surface color, morphology, and chemical composition of NB and HB during accelerated UV weathering were characterized. Meanwhile, the MIV of bamboo samples after different weathering durations was evaluated and the influencing mechanism was explored. The results revealed that the decomposition of starch and hemicellulose during heat treatment resulted in the generation of levoglucosan and acids, thereby providing a new nutrient source and a more suitable environment for mildew growth. HB exhibited superior color stability and anti-weathering characteristics compared to NB. Moreover, certain photodegradation products from HB demonstrated anti-fungal and anti-weathering properties, which resulted in a temporary resistance to mildew in weathered samples. However, after long-term exposure, the cracks on the surface of HB caused by weathering facilitated the colonization of mildew hypha by releasing inner nutrients, leading to severer mildew infection.

Enhancement of Tribological Performance of PTFE/aramid Fabric Liner under High-Temperature and Heavy-Load through Incorporation of Microcapsule/CF Multilayer Composite Structure

Liners suffer from low service life under high-temperature and heavy-load conditions, hindering their widespread use in aerospace applications. A novel strategy of incorporating polyaryl ether sulfone/polymethylphenlsiloxane (PES/PMPS) microcapsules and carbon fibers (CFs) into the polytetrafluoroethylene (PTFE)/aramid fabric liner was used. At the micro-scale level, the worn surface morphology and the transfer film morphology were analyzed to reveal the tribological mechanisms. At the nano-scale level, molecular dynamics simulation was used to analyze the formation mechanism of the transfer film. The results showed that the friction coefficient and wear rate of the liner with microcapsule/CF multilayer structure were reduced by 17% and 24%, respectively. The incorporation of microcapsule/CF multilayer structure can be effectively applied to enhance the tribological performance of liners in harsh operating conditions.

Study on the behavior of AAEMs removal and the evolution of microscopic characteristics in high alkali coal under different acids

ABSTRACT In this paper, the removal behavior of alkali and alkaline earth metals (AAEMs) and the evolution of microscopic characteristics in high alkali coal under the leaching of inorganic and organic acids are studied. The results show inorganic acids have better effect on the removal of AAEMs because of their stronger ability to convert carboxylate and phenol salts into covalent carboxylic acids and phenols. Citric acid has a slightly weaker effect than inorganic acids, and oxalic acid has the least effect. The improvement of slagging characteristics is consistent with the removal ability. Sulfuric acid, hydrochloric acid and citric acid are more effective in enhancing the calorific value of coal, with an enhancement of about 0.60 MJ/kg. After leaching, the pores and cracks in the coal are developed, and the mesopores have a tendency to shift to a lower pore size range. This trend is most pronounced in citric acid leached coal and hydrochloric acid leached coal. Sulfuric acid seriously damage the surface morphology, which results in a tendency of large pore transfer in S-form coal.

Angular- and polarization-insensitive free-standing graphene oxide films for broadband light absorbing applications

Free-standing graphene oxide (FSGO)-based films with angular and polarization insensitivities are demonstrated for broadband absorption applications. The modified Hummers’ method was used to prepare the GO powder. An easily scalable process (evaporation-induced self-assembly) was used to synthesize the FSGO films. The FSGO broadband absorbers with omni-direction and polarization-independent nature was achieved by varying the GO concentrations. The FSGO films were prepared at different GO concentrations to achieve different thicknesses (2–15 μm). The FSGO film with the highest GO concentration (∼10 mg/ml) exhibited high absorptance (α = 0.91) in the broadband region (i.e., 250–2500 nm). The transition from narrow band absorber to a broadband absorber is achieved by varying the GO concentration. The optimized FSGO film (8 mg/ml) shows α of 0.91 with angular and polarization-insensitivity in the visible region. At concentrations <8 mg/ml, the FSGO films are translucent and do not exhibit broadband absorption behavior. Spectroscopic ellipsometry measurements indicate the low refractive index nature of the FSGO films (n = 1.7–1.2 at 400–800 nm). The low refractive index combined with the unique surface morphology of the FSGO films resulted in broadband absorption. Optical simulations were performed to validate the absorption mechanism of the FSGO films.

Fabrication of novel metal oxide nanosheets-decorated carbon nanofibers for highly efficient removal of ultra-small nanoplastics

The extensive use of plastic products leads to white pollution and the formation of nanoplastics (NPs) through physicochemical processes. Due to their large specific surface area and small size, NPs can easily enter the human body, posing significant health risks. In this work, we prepared NiFe2O4 nanosheets-decorated carbon nanofibers (NiFe2O4@CNF) via electrospinning, carbonization, hydrothermal growth, and low-temperature calcination for NPs removal. Characterization techniques, including SEM, FTIR, XRD, XPS, and zeta potential analysis, assessed the surface morphology, functional groups, crystal structure, chemical composition, and surface charge of the NiFe2O4@CNF adsorbent. Adsorption kinetics, isotherms, and thermodynamics studies demonstrated that the adsorption process follows pseudo-second-order kinetics and the Langmuir model, indicating chemisorption and monolayer adsorption with a maximum adsorption capacity of 147.842 mg/g. Thermodynamic data confirmed that the reaction is spontaneous and endothermic. Additionally, the practical application of the adsorbent was evaluated by studying the effects of pH, competing ions, and different water bodies on adsorption behavior, all showing high removal efficiency and robust performance. Computer simulations further provided understanding into the driving forces and the binding sites of adsorption. These results underscore the efficacy of NiFe2O4@CNF for NPs removal and provide critical insights for designing advanced environmental remediation materials.

Recycling of Sewage Sludge: Synthesis and Application of Sludge-Based Activated Carbon in the Efficient Removal of Cadmium (II) and Lead (II) from Wastewater.

The limited supply of drinking water has aroused people's curiosity in recent decades. Adsorption is a popular method for removing hazardous substances from wastewater, especially heavy metals, as it is cheap, highly efficient, and easy to use. In this work, a new sludge-based activated carbon adsorbent (thickened samples SBAC1 and un-thickened samples SBAC2) was developed to remove hazardous metals such as cadmium (Cd+2) and lead (Pb+2) from an aqueous solution. The chemical structure and surface morphology of the produced SBAC1 and SBAC2 were investigated using a range of analytical tools such as CHNS, BET, FT-IR, XRD, XRF, SEM, TEM, N2 adsorption/desorption isothermal, and zeta potential. BET surface areas were examined and SBAC2 was found to have a larger BET surface area (498.386 m2/g) than SBAC1 (336.339 m2/g). While the average pore size was 10-100 nm for SBAC1 and 45-50 nm for SBAC2. SBAC1 and SBAC2 eliminated approximately 99.99% of Cd+2 and Pb+2 out the water under all conditions tested. The results of the adsorption of Cd+2 and Pb+2 were in good agreement with the pseudo-second-order equation (R2 = 1.00). Under the experimental conditions, the Cd+2 and Pb+2 adsorption equilibrium data were effectively linked to the Langmuir and Freundlich equations for SBAC1 and SBAC2, respectively. The regeneration showed a high recyclability for the fabricated SBAC1 and SBAC2 during five consecutive reuse cycles. As a result, the produced SBAC1 and SBAC2 are attractive adsorbents for the elimination of heavy metals from various environmental and industrial wastewater samples.

Fluidized spanlastics for intranasal brain delivery of lacosamide aiming to control Status Epilepticus: Design, Characterization, Ex-vivo permeation, Radioiodination and In-vivo biodistribution studies

Status Epilepticus (SE) is a neurological condition characterized by anomalous brain activity, causing repetitive seizures lasting for more than 5 min or periods of unusual behavior without returning to a normal level of consciousness between episodes. Chitosan has shown various pharmaceutical benefits, particularly in intranasal administration. In the current manuscript, novel ultra-deformable vesicles (fluidized spanlastics) loaded with lacosamide (LCM), a model anti-epileptic drug, were formulated and compared with their chitosan containing counterparts. The formed vesicles were assessed for their particle size (PS), zeta potential (ZP), entrapment efficiency (EE%) and storage stability. Surface morphology, pH and viscosity measurements, in-vitro release study and release kinetics, and ex-vivo permeation across nasal sheep mucosa were carried out on the optimized formulations. The bio-distribution and pharmacokinetic studies were performed using the radioiodinated-LCM (131I-LCM) utilizing different routes of administration to assess the in-vivo performance of intravenous solutions (IVs), intranasal solutions (INs) and the intranasal administered optimized formula (INFS). LCM-vesicles showed PS ranging from 109.90 to 418.4 nm, negative ZP values ranging from −28.00 to −48.30 mV in case of regular vesicles and shifted to +16.70 to +18.72 mV in case of chitosan coated vesicles, high EE% values having a range of 65.76–97.25 % and good storage stability properties. The optimized formulation showed spherical shape and enhanced ex-vivo permeation approximately 4-fold higher compared to LCM solution. The results of the in-vivo study demonstrated that the brain/blood ratio (B/B) of INs was 3.3-fold higher than IVs and INs of 131I-LCM in the first 5 min. Accordingly, the prepared system has been shown to possess a promising potential for brain diagnosis and/or therapy.

A method to integrate hydraulic structure models into 3D terrain models for irrigation infrastructure visualization

Seamless integration of three-dimensional (3D) terrain models and hydraulic structure models is a technical challenge in the construction of 3D virtual scenes for irrigation areas. This study proposes a level-of-detail (LOD)-based dynamic classification integration method for hydraulic structure models and 3D terrain models, called CM-D-LOD. Hydraulic structures are classified according to their point, line, and surface morphologies, as well as their dependence on or independence of the terrain into four categories: point-like hydraulic structures independent of terrain, line-like hydraulic structures dependent on terrain, surface-like hydraulic structures dependent on terrain, and surface-like hydraulic structures independent of terrain. By utilizing the proposed model classification integration method, a visualization management platform for virtual geographical environments of irrigation areas is developed, and experiments are conducted in the Zhuluo Ba Irrigation Area within the large economic zone along China’s eastern coast. Results demonstrate that the integration accuracy can be controlled between 0.2 and 0.7 m and that the 3D virtual scene of the irrigation area can be updated in real time. The proposed classification integration method transforms the traditional global model integration approach into a more efficient one, significantly improving the efficiency of constructing virtual geographical scenes for irrigation areas.

Size and Morphology Dependent Activity of Cu Clusters for CO2 Activation and Reduction: A First Principles Investigation.

Various Cu-based materials in diverse forms have been investigated as efficient catalysts for electrochemical reduction of CO2; however, they suffer from issues such as higher over potential and poor selectivity. The activity and selectivity of CO2 electro reduction have been shown to change significantly when the surface morphology (steps, kinks, and edges) of these catalysts is altered. In light of this, size and morphology dependent activity of selected copper clusters, Cun (n=2-20) have been evaluated for the activation and reduction of CO2 molecule. The phase-space of these copper clusters is rich in conformations of distinct morphologies starting from planar, 2D geometries to prolate-shaped geometries and also high-symmetry structures. The binding efficiency and the activation of CO2 are highest for medium sized clusters (n=9-17) with prolate-morphologies as compared to small or larger sized CunCO2 clusters that are existing mainly as planar (triangular, tetragonal etc.) or highly-symmetric geometries (icosahedron, capped-icosahedron etc.), respectively. The best performing (prolate-shaped) CunCO2 conformations are quite fluxional and also they are thermally stable, as demonstrated by the molecular dynamics simulations. Furthermore, on these CunCO2 conformations, the step-by-step hydrogenation pathways of CO2 to produce value-added products like methanol, formic acid, and methane are exceptionally favorable and energy-efficient.

A study on the mechanisms and influencing factors of interfacial physicochemical interactions between asphalt and mineral aggregates based on multiscale evaluation methods

The elucidation of interfacial physicochemical mechanisms between asphalt and mineral aggregates is vital for comprehending the interface formation in asphalt mixtures and enhancing their performance. To this end, multiscale evaluation methods were used to investigate the mechanisms and influencing factors of interfacial physicochemical interactions between asphalt and mineral aggregates (IPIAMA). Initially, the dynamic shear rheometer (DSR) was used to measure the complex shear modulus (G*) of various asphalt mastics. Subsequently, the interface film thickness was calculated using G* in conjunction with the Hashin and Mori-Tanaka (MT) micromechanical models. This indicator facilitated quantitative assessments and the analysis of influencing factors. The results indicated that the MT model underestimated the interface film thickness by approximately 0.08–0.29 % compared to the Hashin model, a discrepancy attributable to assumptions regarding aggregate particle interlocking. Moreover, the interface film thickness systematically varied with factors such as aggregate content, type of aggregate, and type of asphalt, ranging from 0.24 to 0.53 μm. To further elucidate the IPIAMA mechanisms behind these variations, the fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and the ultraviolet test (UV) testing were conducted. FTIR tests demonstrated that the primary components of mineral aggregates—dolomite, calcite, and quartz—contributed to the physical adsorption increments on asphalt functional groups by 0.0185, 0.0509, and 0.004, respectively. SEM images revealed that dolomite and calcite possessed more surface fissures and pores than quartz. XPS tests showed that calcium carbonate and magnesium carbonate chemically reacted with asphalt, resulting in electron shifts of 0.9 eV and 1.1 eV, respectively, while silicon oxide only exhibited electron shifts when combined with a silane coupling agent-modified asphalt. UV tests demonstrated that lighter asphalt fractions were preferentially absorbed into the pores and micro-cracks of mineral aggregates. Consequently, the complex IPIAMA involved physical adsorption, chemical reactions, and selective absorption, strongly correlating with factors such as mineral composition, surface morphology, and asphalt type.

Characterization and comparability study of a series of novel fluorinated polyacrylates with a rigid cyclohexane mesogenic core

Surface reconstruction has always been a pain point in the study of short-chain perfluoroalkyl acrylate polymers, and how to maintain the balance between environmental protection and good performance is the key issue. We exploited the high efficiency and selectivity of the reaction between the isophorone di-isocyanate group and the hydroxyl group, and the rigid cyclohexane structure contained in their molecule to efficiently prepare a series of novel fluoro acrylate monomers (IFAM) containing rigid cyclohexane as mesogenic core and their homopolymers (PIFAM) with different lengths of short-chain perfluoroalkyl side chains. Their structures, liquid crystal behavior, thermal properties, surface chemical compositions, surface morphologies, and hydrophobicity were characterized and comparatively studied by FTIR, NMR, XRD, POM, DSC, TGA, XPS, AFM, and static/dynamic contact angle tester and dodecafluoroheptyl methacrylate (DFMA) and its homopolymer as a contrast. The results demonstrated that both the synthesized monomers and homopolymers possessed the expected chemical structures with thermotropic liquid crystalline behavior. Furthermore, the thermal stability and hydrophobicity of the polymers increased with the extension of the fluorocarbon chain length. The incorporation of the mesocrystalline motif and appropriate length of fluoroalkyl tails in the PIFAM polymers would enhance hydrophobic stability, as it promoted the crystallinity of the side chains and limited the structural rearrangement of the fluorocarbon chains. This study offers a straightforward method for synthesizing fluoro acrylate polymers with stable surface properties, highlighting their potential application in hydrophobic coatings.

Tailoring the Thermoelectric Properties of 3D-Printed n-Type Bi1.7Sb0.3Te3 with Incorporated Edge-Oxidized Graphene.

Using three-dimensional (3D) printing technology to fabricate Bi2Te3-based thermoelectric (TE) generators opens a potential way to create shape-conformable devices capable of recovering waste heat from thermal energy sources with diverse surface morphologies. However, pores formed in 3D-printed Bi2Te3-based materials by the removal of the organic ink binder result in unsatisfactory performance compared to the bulk materials, which has limited the widespread application of the ink-based 3D printing process. Furthermore, managing the volatile Se element in the n-type materials poses significant technological challenges compared to the p-type counterparts, resulting in a scarcity of research on 3D printing of n-type Bi2Te3. Here, we synthesized edge-oxidized graphene (EOG)-incorporated Se-free n-type Bi1.7Sb0.3Te3 (BST) using a direct ink writing (DIW) process with a binder-free novel ink. The incorporated EOG provides connectivity between small BST grains separated by pores and induces a bimodal-like grain structure during the DIW and sintering process. The optimal EOG content of 0.1 wt % in 3D-printed n-type BST simultaneously achieved both carrier transport control and active phonon scattering, due to its unique microstructure. A maximum ZT of 0.71 was obtained in the 0.1 wt % EOG/BST materials at 448 K, comparable to commercial bulk n-type Bi2Te3-based materials. Further, a single-element device composed of the EOG-BST material exhibited a 2-fold improvement in performance compared to pure-BST. These results open a technological route for the application of 3D printing technology for ink-based TE materials.

Evaluation of antioxidant, antibacterial, and anti-inflammatory activities of deodorizer distillate-derived silver nanoparticles

Silver nanoparticles (AgNPs) were synthesized using a sustainable green approach utilizing deodorizer distillates of canola (CODD) and soybean oil (SODD) as both reducing and capping agents. This synthesis approach resulted in the formation of pale-yellow colored CODD-AgNPs and SODD-AgNPs, which was confirmed by distinctive absorption peaks at 420 nm and 408 nm, respectively via Ultraviolet-Visible (UV–Vis) spectroscopy. Fourier Transform Infrared (FTIR) analysis provided insights into the functional group interactions between CODD and SODD with their AgNPs. X-ray diffraction (XRD) confirmed the face-centered cubic lattice structure of both CODD-AgNPs and SODD-AgNPs. Further characterization via Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) revealed the sizes, shapes, and surface morphologies of CODD-AgNPs and SODD-AgNPs. Assessment of antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method demonstrated superior radical scavenging efficacy by CODD-AgNPs (IC50 value 1.07±0.04 µg/mL) and SODD-AgNPs (IC50 value 1.14±0.23 µg/mL) compared to CODD and SODD. Evaluation of antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) via disc diffusion method revealed potent antibacterial activities of CODD-AgNPs and SODD-AgNPs at 100 µg/mL concentration, surpassing the antibacterial efficacy of CODD and SODD. Furthermore, CODD-AgNPs and SODD-AgNPs exhibited significant anti-inflammatory potential at 500 µg/mL concentration, with IC50 values of 187.2 ± 1.28 µg/mL and 203.9 ± 2.08 µg/mL, respectively, highlighting their potential therapeutic applications. In conclusion, this study demonstrates the effective utilization of CODD and SODD in synthesizing AgNPs with enhanced biological functionalities, making them promising candidates for various biomedical applications.

Comparison of remineralizing efficacy of two novel preparation of arginine and theobromine on white spot lesion - an in vitro SEM analysis

ABSTRACT Purpose Evaluation of the efficacy of two novel formulations of arginine and theobromine in remineralizing artificial enamel defects using in vitro testing techniques- Microhardness and SEM Materials and methods Enamel slabs measuring 3 mm by 3 mm by 1.5 mm were created using 11 healthy premolars that were excised for orthodontic treatment. Group 1 (control, treated with merely a remineralization solution), Group 2 (0.05% arginine in 10 ml distilled water), and Group 3 (2% theobromine in 10 ml distilled water) were the three groups to which the slabs were randomly allocated (n = 7 per group). The pH cycle was run for 14 days, starting with a 72-h demineralization period and ending with 11 days of remineralization in the corresponding solutions. Prior to and during remineralization, microhardness was measured, and surface features were assessed using scanning electron microscopy (SEM). Statistical analysis, including Paired T Test, one-way ANOVA, and post hoc Tukey tests, determined that the mean values were significant at the 0.05 level. Results The control group showed a mean microhardness increase from 192.09 ± 19.30 to 208.58 ± 5.76. The arginine group increased significantly from 217.20 ± 4.24 to 304.00 ± 15.96, and the theobromine group from 214.09 ± 7.67 to 283.14 ± 10.91. Statistical analysis indicated that both arginine and theobromine groups had significantly greater microhardness improvements compared to the control (p < 0.05). SEM revealed that although arginine and theobromine enhanced enamel microhardness, surface morphology remained irregular and non-uniform. Conclusion Arginine and theobromine improve enamel microhardness and promote remineralization, but they do not create a uniform surface texture. Further research is needed to optimize their use and explore long-term effects on enamel surface uniformity.

Effect of different mouthwash solutions on the surface morphology, nanohardness and flexural modulus of nickel-titanium orthodontic wire

Objective: This laboratory study aimed to evaluate the effect of different mouthwash solutions on the surface and mechanical properties of NiTi arch wire. Methods: This experimental study was conducted at the Department of Preventive Dental Sciences, College of Dentistry, Princess Nourah bint Abdulrahman University, Saudi Arabia from September 2023 to November 2023. A 30 mm NiTi wires in length with 0.017 × 0.022” in dimensions were selected and equally divided into four groups: Control (G0) group wires were immersed in distilled water (DW); G1 wires were immersed in antiseptic mouthwash; G2 wires were immersed in fluoridated mouthwash; and G3 wires were immersed in therapeutic mouthwash. Surface morphology, nanohardness, and flexural modulus were evaluated at 24-hours, four weeks, and eight weeks’ time points. Data were statistically analyzed using a two-way analysis of variance (P&lt;0.05). Results: The arch wires immersed in DW showed insignificant effects on surface roughness, nanohardness, and flexural modulus at different time points. However, all the experimental groups showed a significant effect of time and immersion solutions on the said properties (P&lt;0.05). At the end of eight weeks, G3 showed the highest surface roughness (0.346 ± 0.032 µm) and the lowest nanohardness (1.350 ± 0.412 GPa) and flexural modulus (3.960 ± 0.140 MPa) compared to other study groups. Conclusions: The efficiency of tooth realignment could be influenced by the detrimental influence of fluoride and hydrogen peroxide mouthwash solutions on superelastic NiTi arch wires. doi: https://doi.org/10.12669/pjms.40.9.9428 How to cite this: Sawan NM, Gassem AAB. Effect of different mouthwash solutions on the surface morphology, nanohardness and flexural modulus of nickel-titanium orthodontic wire . Pak J Med Sci. 2024;40(9):---------. doi: https://doi.org/10.12669/pjms.40.9.9428 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Improved surface morphology and reduced V-pits density of lattice-matched AlInN films grown by atmospheric pressure metalorganic chemical vapor deposition

AlInN has emerged as a promising material for advanced optoelectronic and electronic devices due to its unique properties. However, achieving AlInN layers with excellent surface morphology remains challenging. Here, Al0.83In0.17N layers lattice-matched to GaN/sapphire were grown by atmospheric-pressure metalorganic chemical vapor deposition at 875 °C. The lowest surface roughness measured by atomic force microscopy was 0.37 nm after optimizing the growth temperature and flux of precursors. The roughness value was constant in the range of 15–72 nm film thickness. Introducing a TMI pre-flow period before AlInN growth, further reduced roughness to 0.28 nm, although a graded inclusion of Ga into the AlInN near the GaN/AlInN interface was observed. This improved surface morphology was interpreted by the In-surfactant effect enriched by the pre-flow in the early stage of AlInN. Additionally, the V-pits density was as low as 2×105 cm−2, primarily due to high growth pressure and also influenced by relatively high growth temperature. Analysis of Al incorporation using second-order reaction model suggests that the severe parasitic reactions between TMA and NH3 at atmospheric pressure can be effectively eliminated by a high total gas flow rate of 72 slm, ensuring in-plane uniformity in surface morphology and relatively good crystalline quality.

Revealing the surface structure and morphology evolution of Co nanoparticle supported on ZrO2 surfaces

The optimization of structure-dependent activity of supported metal catalysts has driven the dynamic determination of the morphology of Co nanoparticles on ZrO2 using atomic-level simulations. Density functional theory (DFT) calculations combined with ab initio molecular dynamics (AIMD) simulations were used to investigate the surface structure, nucleation mechanism and morphology evolution of Con clusters supported on different ZrO2 facets. As the size of the Con (n = 1–5) cluster increases, the competition between Co-Co bonding and the interaction of Con clusters with the ZrO2 surface further promotes the nucleation of larger clusters. Co atoms prefer to nucleate into large clusters on both c-ZrO2(111) and t-ZrO2(101) surfaces, but this behavior is unfavorable on the m-ZrO2(-111) surface. The analysis of electric properties suggests that the types of hybrid orbitals and the number of electron transfer accounts for the difference in energies of Con clusters on ZrO2 surfaces. Further, the AIMD simulations verified the stable structure of small Co5 cluster obtained by DFT, and predicted the morphology of large Co13 clusters on ZrO2 surfaces under realistic reaction conditions, consistent with the experimental SAM images. Our work provides an intuitive understanding of structure and morphology evolution of catalysts for the targeted design of catalysts to achieve the desired activity and explore more reaction possibilities.