Surface Scanning Electron Microscopy Research Articles

The Physicochemical Properties and Antioxidant Activities of the Hawthorn Pectin Extracted Using Ultra-High Pressure Assisted Acid Extraction (UPAAE).

This study aims to investigate the positive effects of ultra-high pressure assisted acid extraction (UPAAE) on both physicochemical properties and antioxidant activities of hawthorn pectin. The basic indicators, structure characterization, and antioxidant activities were measured, which could indicate the disadvantages and advantages among traditional water extraction (WE), acid extraction (AE), and UPAAE. The results show that the hawthorn pectin of UPAAE has a decrease in esterification degree, protein content, and total polyphenols, but has an increase in total galacturonic acid aldehyde compared to the hawthorn pectin of AE. In the Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) analyses, the hawthorn of UPAAE has typical pectin absorption peaks in the FT-IR spectrum and a distinct layered structure in the SEM surface image. The ion chromatography profiles show that the molar ratio of galacturonic acid to arabinose in the hawthorn pectin of UPAAE increases and 5.50 μg/mg ribose appears compared to the pectin of AE and WE. The high performance gel permeation chromatography (HPGPC) profile indicates that the molecular weight distribution of hawthorn pectin of UPAAE is more concentrated and has the highest molecular weight compared to the pectin of the other two extraction methods. In the vitro antioxidant activity analysis, the pectin of UPAAE exhibits the highest scavenging rate against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (93.70%), which is close to the scavenging rate of vitamin C (96.30%). These findings demonstrated that UPAAE is a more efficient and environmentally friendly method for pectin extraction from hawthorn. It is also an effective way to enhance its antioxidant activity, which has great application prospects in the food industries.

Study of the Microstructure of Coal at Different Temperatures and Quantitative Fractal Characterization.

In order to understand the influence of underground coal fires on coal fractures and pores, mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) are combined to study the development of coal pore and fracture under high-temperature treatment and calculate the fractal dimension to analyze the relationship between the development of coal pore and fracture and the fractal dimension. The results show that the volume of pores and fractures of the coal sample (C200) treated at 200 °C (0.1715 mL/g) is greater than that of the coal sample (C400) treated at 400 °C (0.1209 mL/g), and both are greater than the original coal sample (RC) (0.1135 mL/g). The volume increase is mainly due to mesopores and macropores, and the proportions of mesopores and macropores in C200 were 70.15 and 59.97% in C400. The MIP fractal dimension shows a decreasing trend with the increase of temperature, and the connectivity of coal samples improved with the increase of temperature. The changes in volume and three-dimensional fractal dimension of C200 and C400 showed the opposite trend and are related to the different stress of coal matrix at different temperatures. The experimental SEM images confirm that the connectivity of coal fractures and pores improves with the increase of temperature. Based on the SEM experiment, the larger the fractal dimension, the more complex the surface is. The SEM surface fractal dimensions indicate that the surface fractal dimension of C200 is the smallest and that of C400 is the largest, which is consistent with the observations made by SEM. The combination of the two fractal dimensions is used to characterize the self-similarity of coal using the fractal dimension difference. When the temperature increased to 200 °C, the unordered expansion of the coal sample resulted in the largest fractal dimension difference and the lowest self-similarity. When heated to 400 °C, the fractal dimension difference of the coal sample is the smallest, and the microstructure of coal shows a regular groove-like development.

Nano-microscopic analysis on the interaction of new and old asphalt mortar in recycled asphalt mixture

Asphalt and fillers form asphalt mortar, which plays the role of bonding and filling in the asphalt mixture, and has a significant impact on the performance of the asphalt mixture. However, it is very necessary to fully study the interaction between old and new asphalt mortar in recycled asphalt mixture. In this study, molecular dynamics simulation software (Material Studio 8.0) was used to study the interface action of old and new asphalt mortar and the mechanical properties of the mixed old and new asphalt mortar. Quantification and characterization of solubility parameters, interaction energy, and mechanical properties from a microscopic perspective. In order to better demonstrate the simulation results, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to conduct microstructural tests to clarify the interaction of old and new asphalt mortar in recycled asphalt mixtures. The results show that at 190 °C, the solubility parameter difference of the old and new asphalt mortar molecular models and the interaction energy are in the best mixing state. At this temperature, the SEM surface morphology characterization is relatively good; the quantitative characterization of the functional groups also shows that the two have a good relationship. the miscible state. The mechanical properties of new and old asphalt mortars are described at the nano and micro scales, and the mechanical properties recover after miscibility. The above results show that it is a comprehensive and reliable method to conduct multi-scale research on the interaction of old and new asphalt mortar in recycled mixtures, and provide new ideas for the research of polymer materials.

Electrochemical Deposition of Polypyrrole in the Presence of Silanes as Adhesion Promoters.

Polypyrrole adhesion to indium-tin oxide electrodes was improved by adding pre-hydrolyzed alkoxysilanes to the electrodeposition media. The pyrrole oxidation and film growth rates were studied by potentiostatic polymerization in acidic media. The morphology and thickness of the films were studied by contact profilometry and surface-scanning electron microscopy. The bulk and surface semiquantitative chemical composition was studied by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Finally, the adhesion was studied by scotch-tape adhesion test, where both alkoxysilanes showed a significant improvement in adhesion. We proposed a hypothesis for the improvement in adhesion, that involves the formation of siloxane material as well as in situ surface modification of the transparent metal oxide electrode.

Electrochemical and computational studies of an expired vilazodone Drug as environmentally safe corrosion inhibitor for aluminum in chloride medium

Through using chemical and electrochemical methods, the theoretical and experimental investigation of the expired vilazodone drug's ability to prevent corrosion on aluminium (Al) in a corrosive medium of HCl (1 M) has been examined. Weighing tests (WL), electrochemical (impedance spectroscopy (EIS), potentiodynamic polarization (PDP)), atomic force microscopy (AFM), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) tests at 25 °C have all been used to investigate Vilazodone's capability to prevent corrosion of Al in 1 M HCl in the concentration in the range of 25–150 ppm. The corrosion inhibition effect of the investigate Vilazodone's against Al in acid environment was investigated weight loss and electrochemical methods. The highest % inhibition efficiency (%IE) was 95% resulted from weight loss technique at the highest concentration for inhibitor. According to the PDP data, this examined vilazodone function as a mixed-type inhibitor, impacting both the anodic and cathodic reactions. The inhibitors covered the active points of the metal surface, according to electrochemical impedance spectroscopy (EIS), to prevent corrosion. It was discovered that the inhibitor adsorption on the Al surface obeyed the Langmuir adsorption isothermal model. AFM, SEM, and FTIR surface examinations proved the inhibitor had a significant protective effect against Al dissolution in 1 M HCl. The outcomes from chemical and electrochemical methods are relatively consistent. Vilazodone acted as an effective corrosion inhibitor, according to all of the experimental data.

Comparative Results of Vocal Fold Injury According to the Fiber-Based Laser in a Rabbit Vocal Fold Model

We assessed the safety of flexible fiber-based lasers including the potassium-titanyl-phosphate (KTP), CO2, and Holmium lasers using a rabbit vocal fold model and provided the safety evidence of laser before human clinical trial. In all, 120 male New Zealand white rabbits were used. Each laser was used to induce acute and chronic vocal fold injuries in 40 rabbits. The same laser energy with the same intensity and frequency were used in all cases, and we evaluated outcomes via surface scanning electron microscopy (SEM) and histological examination 1 day after injury. Histological and high-speed vocal fold vibration examinations were evaluated 1 month after injury. Surface injury roughness grading was done via SEM, and the Acute injury ratio and lamina propria (LP) ratio were also calculated. The dynamic glottal gap was measured through functional analyses based on recordings from a high-speed digital camera. The Holmium laser caused significantly more vocal fold damage than did the KTP and CO2 lasers as revealed by SEM and evaluation of acute and chronic injuries. Functional analysis with high-speed digital camera indicated that the holmium laser reduced dynamic glottal gap compared with the normal vocal fold, where the other lasers did not. The histological and functional analyses of rabbit vocal fold experiments indicated that fiber-based laryngeal laser surgery for vocal fold lesions could be performed relatively safely using a KTP or CO2 laser.

Uniformly dispersed flowery EuZrSe3 derived from the europium-based metal–organic framework for energy storage devices

Recently, it has become more popular to use in-situ growth of transition metal chalcogenides for efficacious supercapacitor (SCs) applications. Metal-organic framework (MOF) is considered as a good source of precursor for a transition metal. Herein, Eu-MOF was used as a precursor for Eu transition metal to fabricate EuZrSe3 via the wet chemical method. The various physical and chemical characteristics such as X-ray diffraction spectroscopy (XRD), surface Scanning electron microscopy (SEM), and Brunner-Emmet Teller were utilized to study the phase orientation, crystallinity, morphology, and textual properties of fabricated material, respectively. All the electrochemical parameters like polarization curve (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) for estimating various parameters such as specific capacitance (Cs) around 1543 F/g & detected a remarkable energy density of 97 Wh/kg at a current density around 3.0 A/g in 2.0 M alkaline KOH electrolyte. Enhanced performance of the fabricated novel electrode owing to its huge electroactive surface area and excellent electrochemical conductivity and good morphology. Despite its greater specific energy (97 Wh/kg) and high-power density (658.8 W/kg), it also has 93.58 % retention efficiency after 10,000 cycles.

Evaluation of Nisin-Loaded PLGA Nanoparticles Prepared with Rhamnolipid Cosurfactant against S. aureus Biofilms.

In this article, nisin(N)-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) were prepared using the single-solvent evaporation method with a rhamnolipid(R) cosurfactant. The antibacterial-antibiofilm effects of the prepared formulation and free nisin were evaluated against S. aureus (ATCC 25923). The characterization of NPs was analyzed using scanning electron microscopy (SEM), Zetasizer and Fourier-transform infrared spectroscopy (FTIR). The drug encapsulation efficiency and loading capacity percentages of NPs were calculated by the spectrophotometric method. The drug release of N-loaded PVA-R-PLGA NPs was determined by the dialysis bag method. The antibacterial and antibiofilm activity of N-PVA-R-PLGA NPs was determined. PVA-R-PLGA-NPs were found to be spherical with sizes of ~140 nm, according to the SEM analysis and surface charge of N-PVA-R-PLGA NPs -53.23 ± 0.42 mV. The sustained release of N (≥72% after 6 h) was measured in PVA-R-PLGA-NPs. The encapsulation efficiency percentage of N-PVA-R-PLGA NP was 78%. The MIC values of free nisin and N-PVA-R-PLGA NPs were 256 μg/mL and 64 μg/mL, respectively. The antibiofilm inhibition percentages of free nisin and N-PVA-R-PLGA NPs were 28% and 72%, respectively. These results reveal that N-PVA-R-PLGA NPs are a promising formulation for use in infections caused by S. aureus compared to free nisin.

Effect of hydraulic retention time on performance of autotrophic, heterotrophic, and split-mixotrophic denitrification systems supported by polycaprolactone/pyrite: Difference and potential explanation.

Biological denitrification is still the most important pathway to purifying nitrate-containing wastewater. In this study, pyrite (FeS2 ) and polycaprolactone (PCL) were used as electron donors to construct sole or combined denitrification systems, that is, pyrite-based autotrophic denitrification (PAD) system, PCL-supported heterotrophic denitrification (PHD) system, and split-mixotrophic denitrification system (combined PAD + PHD), all of which were operated under five different hydraulic retention times (HRTs) for 150 days. The results showed that the removal rates (RE) of nitrate (NO3 - -N) and inorganic phosphorus (PO4 3- -P) by PAD were 91% and 94%, respectively, but the effluent sulfate (SO4 2- ) concentration was as high as 168.2mg/L; the removal rate of NO3 - -N by PHD was higher than 99%, but the PO4 3- -P could not be removed ideally; the removal rates of NO3 - -N and PO4 3- -P by PAD + PHD were higher than 95% and 99%, respectively, and the effluent SO4 2- concentration was only 7.2mg/L. Through the analysis of the surface scanning electron microscope (SEM) images of the two kinds of media before and after use, it was found that the coupled mode of PAD + PHD was more favorable for biofilm formation than the sole PAD or PHD process, and the microorganisms in the PAD + PHD mode made more full use of electron donors. Moreover, the biomass of the PAD + PHD mode was lower than that of the PAD or PHD process, but the denitrification efficiency of the coupled mode was more efficient, indicating that the functional microorganisms in the PAD + PHD mode might have a certain synergistic effect. PRACTITIONER POINTS: Removal rates of NO3 -, PO4 3 -, and SO4 2 - by PAD were 91%, 94%, and -233%, respectively. Removal rate of NO3 - by PHD exceeded 99%, but PO4 3 - could not be removed ideally. Removal rates of NO3 -, PO4 3 -, and SO4 2 - by PAD + PHD were 95%, 99%, and 86%, respectively. The coupled mode was more favorable for biofilm formation than the sole PAD or PHD. The coupled mode had lower biomass but got more excellent denitrification efficiency.

Prediction of surface morphology and reflection spectrum of laser-induced periodic surface structures using deep learning

Laser-induced periodic surface structures have been extensively explored as an enabling tool for fabricating various optical surfaces because the resulting surface ripples can effectively modify surface reflectance. Here, we propose a deep-learning-based model for predicting high-quality surface scanning electron microscopy (SEM) images with detailed surface morphology corresponding to unexplored process conditions. In addition, the reflectance value at 550 nm and reflection spectra from the generated (or original) SEM images were predicted. To obtain training data, stainless steel 304 specimens were processed with femtosecond laser pulses on a large process window consisting of 32 process conditions to obtain SEM images with various surface morphologies and corresponding reflection spectra. The image prediction model is based on a conditional generative adversarial network, which generates a surface SEM image from the laser fluence and scanning speed values. The reflectance prediction model was developed based on ResNet152 and Long-Short Term Memory network. The average accuracies for the pattern period and ripple width were 98.2 and 94.6 %, respectively, and the L2 norm error for the reflection spectra was less than 4 %. It was demonstrated that the reflection spectra can be accurately predicted using only surface images, which can also be accurately generated from process parameters.

Three-dimensional bioprinting of mucoadhesive scaffolds for the treatment of oral mucosal lesions; an in vitro study

BackgroundChronic oral lesions could be a part of some diseases, including mucocutaneous diseases, immunobullous diseases, gastrointestinal diseases, and graft versus host diseases. Systemic steroids are an effective treatment, but they cause unfavorable and even severe systemic side effects. Discontinuation of systemic corticosteroids or other immunosuppressive drugs leads to relapse, confirming the importance of long-term corticosteroid use. The present study aims to fabricate a mucoadhesive scaffold using three-dimensional (3D) bioprinting for sustained drug delivery in oral mucosal lesions to address the clinical need for alternative treatment, especially for those who do not respond to routine therapy.Methods3D bioprinting method was used for the fabrication of the scaffolds. Scaffolds were fabricated in three layers; adhesive/drug-containing, backing, and middle layers. For evaluation of the release profile of the drug, artificial saliva was used as the release medium. Mucoadhesive scaffolds were analyzed using a scanning electron microscope (SEM) and SEM surface reconstruction. The pH of mucoadhesive scaffolds and swelling efficacy were measured using a pH meter and Enslin dipositive, respectively. A microprocessor force gauge was used for the measurement of tensile strength. For the evaluation of the cytotoxicity, oral keratinocyte cells' survival rate was evaluated by the MTT method. Folding endurance tests were performed using a stable microsystem texture analyzer and analytic probe mini tensile grips.ResultsAll scaffolds had the same drug release trend; An initial rapid explosive release during the first 12 h, followed by a gradual release. The scaffolds showed sustained drug release and continued until the fourth day. The pH of the surface of the scaffolds was 5.3–6.3, and the rate of swelling after 5 h was 28 ± 3.2%. The tensile strength of the scaffolds containing the drug was 7.8 ± 0.12 MPa. The scaffolds were non-irritant to the mucosa, and the folding endurance of the scaffolds was over three hundred times.ConclusionThe scaffold fabricated using the 3D bioprinting method could be suitable for treating oral mucosal lesions.

Effect of Bonding Protocols on the Performance of Luting Agents Applied to CAD-CAM Composites.

This in vitro study aimed to evaluate the effect of different bonding strategies on the micro-shear bond strength (μSBS) of luting agents to CAD–CAM composites. Surface scanning electron microscopy (SEM) and spectroscopy by energy-dispersive X-ray spectroscopy (EDS) were performed to analyze the surfaces of the composite before and after bonding treatment. Three CAD–CAM composites were evaluated: Lava Ultimate restorative (LU), Brava Blocks (BR), and Vita Enamic (VE). The LU and BR surfaces were sandblasted using aluminum oxide, while the VE surfaces were etched using a 5% hydrofluoric acid gel according to the manufacturers’ recommendations. All surfaces were subjected to the following bonding strategies (n = 15): adhesive with silane and MDP (ScotchBond Universal, 3M Oral Care, St Paul, MI, USA); adhesive with MDP (Ambar Universal, FGM, Joinville, Brazil); adhesive without silane or MDP (Prime&Bond Elect, Dentsply Sirona, Charlotte, NC, USA), pure silane without MDP (Angelus, Londrina, Brazil), and pure silane with MDP (Monobond N, Ivoclar Vivadent, Schaan, Liechtenstei). Afterwards, tygons were filled with RelyX Ultimate (3M Oral Care), AllCem (FGM), or Enforce (Dentsply Sirona), which were light-cured and subjected to the μSBS test. Data were analyzed using two-way ANOVA and Bonferroni’s post hoc test (α = 0.05). Additional blocks (n = 15) were subjected to scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) before and after the surface treatment. The μSBS values on VE surfaces were higher than those observed on LU and BR surfaces (p < 0.001). Silane without MDP (Allcem) promoted the highest μSBS values, while silane with MDP (RelyX Ultimate) provided the highest values among all bonding strategies (p < 0.001). Enforce promoted no significant difference in μSBS values. SEM and EDS analyses detected noticeable changes to the surface morphology and composition after the surface treatment. The effectiveness of the bonding strategy may vary according not only to the CAD–CAM composite but also to resin cement/bonding agent/silane used.

Comparative Study into Microstructural and Mechanical Characterization of HVOF-WC-Based Coatings

The main objective of this work was to characterize and compare the microstructural and mechanical properties as well as erosion resistance of WC-12Co and WC-10Co-4Cr coatings. The High Velocity Oxy Fuel (HVOF) process was applied to carbon manganese steel API 2H typically used in oil and gas industries. Microstructural characterization of feedstock powder and coatings was conducted using scanning electron microscope (SEM), energy dispersive X-ray spectroscopic (EDS) analysis, X-ray diffraction (XRD) for phase determination, powder particle size distribution, and surface roughness measurement. The average particle size of the former powder was 13.7 µm whereas it was 28.1 µm for the latter. The results showed that the smaller particle size tends to melt easier than the larger one, as deduced from SEM images and surface roughness measurements. EDS and XRD results of both coatings indicated the occurrence of WC decomposition where the powder particle size plays a significant role in these results. Mechanical characterization was discussed through comparing hardness, erosion, and adhesion test results of both coatings. WC-10Co-4Cr coating exhibited higher hardness than WC-12Co as well as higher erosion resistance, due to the extent of decomposition of WC and also to carbide particle size within the coating layer; these are the same reasons for the superior adhesion strength of the former coating compared to the latter one as per ASTM Standard “C633- 13”.

Photocatalytic Activity in the In-Flow Degradation of NO on Porous TiO2–Coated Glasses from Hybrid Inorganic–Organic Thin Films Prepared by a Combined ALD/MLD Deposition Strategy

A combined ALD/MLD (where ALD and MLD stand for atomic and molecular layer deposition, respectively) deposition strategy using TiCl4, H2O and HQ (hydroquinone) as precursors has been applied for the preparation of inorganic–organic thin films on soda-lime glasses. The alternate deposition of TiO2 layers, by pulsing TiCl4/H2O (ALD), and hybrid layers, using TiCl4/HQ (MLD), results in the formation of thin films that are precursors for porous TiO2-coatings after removal of the HQ template by annealing. The coated-glassed show good photocatalytic activity in the degradation of NO with up to 15% reduction of NO concentration in three successive photocatalytic cycles of 5 h each. Surface Scanning Electron Microscopy (SEM) images show that the TiO2-coating is composed of large grains that are made up of finer subgrains resulting in a porous structure with an average pore size of 3–4 nm. Transmission Electron Microscopy (TEM) images show two regions, a porous columnar structure on top and a denser region over the glass substrate. Energy Dispersive X-Ray (EDX) analysis, nanocrystal electron diffraction and Raman spectroscopy confirm the presence of the anatase phase, which, together with the porosity of the material, accounts for the observed photocatalytic activity.

Sequential Microwave-Ultrasound Assisted Extraction of Flavonoid from &lt;i&gt;Moringa oleifera&lt;/i&gt;: Product Characteristic, Antioxidant and Antibacterial Activity

Moringa oleifera leaves contain secondary metabolites in flavonoid compounds known to prevent several diseases. Therefore, appropriate extraction methods are required to produce extracts with a high yield of flavonoids from Moringa. In this study, the extraction from Moringa leaves was carried out using the sequential microwave/ultrasound-assisted extraction (MUAE) method compared with sequential ultrasound/microwave (UMAE), microwave (MAE), ultrasound (UAE), and maceration (ME). The effects of the time, temperature, and percentage of ethanol were studied on total flavonoid content using AlCl3 colorimetric assay. The extracts were analyzed by Scanning Electron Microscopy (SEM), Fourier Transforms Infrared Spectrophotometry (FTIR), and High-Performance Liquid Chromatography (HPLC). The antioxidant and antibacterial activities were tested using DPPH-scavenging and disc diffusion methods. The results of SEM surface analysis on various extraction methods show differences on each surface. The FTIR spectrum showed the presence of flavonoid O–H at 3200 cm–1, C=O at 1621 cm–1, and C–O at 1019 cm–1. In the results of HPLC, MUAE extracts 16.70 mg/ 100 g flavonoid quercetin at the retention time of 4.5 min, with the highest total flavonoids (2.89 mg QE/g), the highest antioxidant activity (IC50 72.31 µg/mL), and highest antibacterial activity (S. aureus 7 mm, E. coli 2 mm).

Synthesis, optimization and characterization of zinc oxide nanoparticles prepared by sol–gel technique

The study conducted endeavors on the synthesis of Zinc Oxide nanoparticles (ZnO NPs) using the sol–gel method at discrete calcination temperatures (500 °C, 700 °C, 900 °C). ZnO NPs were prepared using Zinc Acetate Dihydrate as a precursor, triethanolamine (TEA) as surfactant and ethanol as a solvent in the medium of Ammonium hydroxide and distilled water. The ZnO NPs thus obtained were characterized for structural and surface morphology analysis using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. XRD shows nothing but the characteristic peaks related to the ZnO phase, thus confirms the presence and purity of ZnO NPs. Also, the crystal size of NPs was derived using full-width half maxima (FWHM) of the highest peak of XRD spectra using Debye-Scherrer formula. SEM surface analysis reveals that the synthesized ZnO NPs are near-spherical in structure and homogeneous in nature with typical size ranging between 500 and 700 nm.

Experimental investigation of selective laser melting parameters for higher surface quality and microhardness properties: taguchi and super ranking concept approaches

In the current study, near net-shaped selective laser melting (SLM) technology was employed to build nickel-based superalloy Inconel 625 (IN625) parts with good quality. Taguchi method was employed to formulate a systematical study, analyze, and optimize the influencing factors, i.e., laser power (LP), scan speed (SS) and hatch distance (HD) on the resulting micro-hardness (MH) and surface roughness (SR) of the build samples. Scanning electron microscope (SEM) and X-ray diffraction analysis were carried out to characterize the powder morphology (spherical shaped particle possessing the size of 35 ± 6 μm) and the surface of the build samples. Laser power was the most contributing factor on the analyzed parameters (MH and SR), followed by the scanning speed and hatch distance. Taguchi determined optimal condition (MH: LP = 270 W, SS = 800 mm/s, HD = 0.08 mm; SR: LP = 270 W, SS = 800 mm/s, HD = 0.08 mm) which resulted in higher microhardness of 416 HV and lower surface roughness of 2.82 μm. Higher MH was attributed to the minimal porosity, while the uniform smooth surface of the build samples resulted in low SR as evident from the SEM images and surface texture analysis. Super ranking concept (SRC) was used to optimize the MH and SR simultaneously, by determining a single optimal condition (LP = 300 W, SS = 600 mm/s, HD = 0.10 mm). The obtained optimal condition resulted in a MH of 382 HV, and a SR of 3.92 μm. The results of optimal conditions are validated subjected to SEM morphologies.

Microstructural evolution of oxygen incorporated CdTe thin films deposited by close-spaced sublimation

In this work, cadmium telluride (CdTe) thin film was deposited in vacuum (pure argon ambient) as well as different argon (Ar) and oxygen (O2) ambient conditions using close-spaced sublimation (CSS) method at the deposition pressure of 1 Torr. The deposited films were characterized via X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), UV–Vis spectrophotometer and Hall Effect measurement for the analysis of structural properties, morphology, optical properties and electrical properties, respectively. XRD patterns exhibited almost similar preferential orientation plane at (111) irrespective of the O2 concentration. SEM surface morphology microstructure revealed that O2 presence had a substantial effect on grain size reaching up to 7.19 µm. Optical properties also demonstrated insignificant changes in the direct band gap values of around 1.48 eV. Carrier concentration showed an upward trend in the order of 1013 cm−3, whereby resistivity and mobility did not change substantially either in vacuum (pure Ar ambient) or in Ar/O2 ambient.

Preparation and characterization of some composite phosphate glass-Polyaniline derivatives studying their antimicrobial activity

The present work involved the preparation of mixed composite derivatives from phosphate glass and polyaniline together with additional doped samples containing increasing CuO or ZnO (3→10 mol%). All prepared pure glass and polyaniline together with their composites were characterized by structural FTIR analysis, X-ray diffraction examinations and surface scanning electron microscope (SEM). Further antimicrobial properties of the base glass, base polyaniline and composites with one of the two dopants (CuO,ZnO) were studied and evaluated. FT infrared spectrum of the base undoped glass revealed vibrational bands due to PO4 tetrahedral groups which are extended from 400 cm-1 to 1500 cm-1 within the mid region. The base polyaniline exhibits extended vibrational bands characteristic for vibrations of C – C, C- H, C = C and N – H groupings. The composite (glass + polyaniline) showed mixed or interfering vibrations of all constitutional groupings. The dopant oxides showed only limited variations to the IR spectra. X-ray diffraction patterns of base and doped glass samples revealed only undefined humps with no indication for crystalline species but only amorphous structures. On the other hand, polyaniline revealed two diffraction peaks which were correlated with crystalline components of the polymerized granular texture of the (PANI). SEM investigations revealed mostly amorphous texture for the parent glass and its derivatives but the polyaniline exhibited granular texture which extended to all composites in different forms. Glass and polyaniline composites showed varying responses to micro-organisms. In general, the composites showed favourable data.

Some polymeric imidazolates from alkylimidazolium as corrosion inhibitors of API 5L X52 steel in production water

In this work, the synthesis route and evaluation of two poly(ionic liquids) (PolyILs) derived from alkylimidazolium imidazolate to be used as corrosion inhibitors (CIs) of API 5L X52 steel exposed to oil reservoir production water (PW) are discussed. The corrosion inhibition performance of the PolyILs was investigated by potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). According to the PDP analysis, it was concluded that the PolyILs could be classified as mixed-type CIs with anodic tendency, featuring maximal inhibition efficiency (η) of 80%. The adsorption mechanism occurred through the blocking of active sites by means of electrostatic attraction forces and formation of chemical bonds. The SEM and AFM surface analyses evidenced that the metal surface in the presence of the PolyILs was less damaged by steel corrosion. Finally, the XPS studies confirmed that the CI interaction with the steel surface reduced the amount of produced corrosion products such as FeOOH and/or FeCO3.