Energy Dispersive Spectroscopy Analysis Research Articles

Fabrication of MAX‐Phase Composites by Novel Combustion Synthesis and Spontaneous Metal Melt Infiltration: Structure and Tribological Behaviors

In this work, a new scheme is developed and experimentally tested for fabricating family of MAX–metal composites. This scheme combines the combustion synthesis (CS) process to obtain a porous MAX‐phase skeleton and process of metal melt infiltration spontaneously, which is then used to fabricate Ti3SiC2–TiC–Sn and Ti3SiC2–TiC–(Sn–Pb) composites. The resultant composite samples have an uneven density along the length, which steadily decrease from the point of contact of the sample with the molten tin to the opposite edge. Existence of Ti3SiC2, TiC, Sn, and (Sn and Pb) phases in the composite samples is confirmed using X‐ray diffraction and energy‐dispersive spectroscopy analyses. Comparative tribological characterizations are performed on fabricated Ti3SiC2–TiC–Sn and Ti3SiC2–TiC–(Sn–Pb) composite samples. Herein, these results are compared against standalone Sn and Sn–Pb samples as baseline and reveal major differences in friction and wear mechanisms due to addition of select MAX phases via novel CS process. As a whole, in the present study, a novel synthesis process is established to fabricate MAX‐phase composites and its enhanced tribological behavior and wear mechanisms which can have plethora of applications ranging from aerospace, automotive to biomedical sectors, are validated.

New strategy to improve the accuracy of quantitative analysis of energy dispersive spectroscopy

Elemental quantification of several single crystalline TEM samples of intermediate thickness range that cannot be quantified by the thin-film approximation method and the ZAF correction were investigated using wedge-shaped samples of known thickness fabricated by the FIB technique. ‘Thickness factor (T F )’ and ‘Thickness correction coefficient (T C )’ were proposed as error correction items of ‘thin-film approximation method’ to minimize the quantitative error that occurs when quantifying samples of intermediate thickness with TEM-EDS. As the result of T F correction, the quantification error in an Al2O3 TEM sample by TEM-EDS was reduced from about 52.15% to less than 3.28 (± 2.57) % by the correction of only one time. The self-absorption corrected line profiles and self-absorption corrected elemental mapping images in TEM samples of intermediate thickness range were also obtained by T F correction. As an example of application by T F correction, we proposed a novel method measuring thin-film thickness in normal TEM without the EELS system. The T F correction technique is a unique method to overcome the limitation of EDS quantification in the intermediate thickness range. This technique can effectively quantify characteristic x-ray lines less than 1,000 eV in the sample having intermediate thickness ranges using the conventional TEM-EDS system. It is expected to contribute significantly to understanding various characteristics or material nature related to material composition and sample thickness in nanomaterials because it provides more precise quantitative analysis information than current commercial EDS systems.

Effect of Individual Alloying Addition on the Microstructure and Creep Behavior of Squeeze Cast AZ91 Magnesium Alloy

The microstructure of AZ91 (Mg-Al) alloy is comprised of α-Mg and β-Mg17Al12 massive phase. The lower melting point associated with the β-Mg17Al12 phase results in poor creep resistance of the alloy. In the present study, the AZ91 alloy with the addition of calcium (Ca, 1wt%) and cerium (Ce, 1wt%) is cast, and their effect on the microstructure and creep behavior of AZ91 alloy have been investigated. Thermally stable phases such as Al2Ca and Al11Ce3 are introduced in the AZ91 alloy through the addition of Ca and Ce elements. Energy dispersive spectroscopy (EDS) and x-ray diffraction analysis confirmed the presence of these intermetallic phases in the microstructure. Tensile creep tests on the as-cast samples were performed at 175°C temperature under 50 MPa stress. The study shows that the creep resistance of AZ91 alloy is greatly improved with the presence of Al2Ca and Al11Ce3 intermetallic phases because of their better thermal stability than β-Mg17Al12.

Sustained antibacterial activity of orthodontic elastomeric ligature ties coated with a novel kombucha-derived bacterial nanocellulose: An in-vitro study.

Incipient carious lesions, the most common complication in orthodontic patients with fixed appliances, call for the development of novel preventive dental materials that do not rely on patient adherence. The present study aimed to assess the ability of elastomeric ligatures coated with bacterial nanocellulose (BNC) to deliver sustained antibacterial activity, during the standard 28-day interval between orthodontic appointments, without compromising their mechanical properties. Kombucha membrane was used to produce cellulose as a secondary product from the fermentation of tea broth with symbiotic bacteria and yeast culture. Characterization of BNC-coated elastomeric ligatures was performed using Fourier Transform Infrared Spectroscopy and Energy Dispersive Spectroscopy analysis. The samples were pre-treated by immersion first in isopropyl alcohol, then in 8 mL nanocellulose solution for 7 days. Tensile strain and strength of the BNC-coated and conventional ligatures were evaluated using a tensile testing machine. Direct contact and agar diffusion tests were performed to assess the antibacterial activity of nanocellulose. In addition, the release profile of BNC was evaluated. Data analysis was performed by one-way analysis of variance (ANOVA) followed by post-hoc Tukey's test and Wilcoxon signed-rank test. P values less than 0.05 was regarded as significant. There was no statistically significant difference in tensile strain and strength between the BNC-coated and conventional ligatures. The coated ligatures provided sustained antibacterial activity during the required 28 days. The use of BNC-coated elastomeric ligatures in patients with fixed orthodontic appliances might be a promising solution to plaque formation and subsequent enamel decalcification.

Synthesis of carbon quantum dots from waste Phaseolus vulgaris for the development of a fluorescence sensing probe to detect plasticizer in cookies

Dibutyl phthalate (DBP) is a commonly used plasticizer in the fabrication of various packaging materials, however upon exposure, it poses significant health and environmental hazards. These plasticizers consist of low-molecular-weight components, which permeate easily into the food matrix. Hence, the development of a cost-effective detection technique is necessary for the detection and monitoring of DBP. Therefore, this research focuses on the utilization of broken Phaseolus vulgaris-derived carbon quantum dots (PV-CQDs) as a fluorescent probe for the detection of DBP in cookies. Herein, PV-CQDs were synthesized through a hydrothermal reaction, which exhibited a blue color under UV-luminescence and localized surface plasmon resonance spectrum at 238 and 270 nm. The highest fluorescence emission intensity was recorded at 428 nm. The resulting PV-CQDs exhibited an average particle size of 1.22 ± 0.05 nm and prominent peaks obtained during infrared spectroscopy were found to be of carboxylic and hydroxyl functional groups, respectively. Transmission electron microscopy and energy dispersive spectroscopy analyses confirmed the spherical morphology and elemental composition, which include C (58.05% by weight) and O (41.92% by weight), respectively. The topographical height profile of the PV-CQDs was observed by atomic force microscopy and it was found to be approximately 100 µm with a thickness of 2.9 µm . The inherent fluorescence of CQDs demonstrated notable quenching efficiency when exposed to varying concentrations of 0.1, 0.2, 0.3, 0.4, 0.5, 1, 5, and 10 µM of DBP residue, resulting in a linear relationship with a high detection sensitivity of 3.19634 µM. Furthermore, the developed method was successfully implemented to determine DBP in cookies, achieving recovery rates within the range of 97–99%. Thus, the rapid sensing capabilities of CQDs could be highlighted as their promising potential for the detection of DBP in food products.

Ag‐Decorated Chrysanthemum‐Like CuO–TiO2 Thin Film: Enhanced Photocatalytic Degradation of Rhodamine B

Photocatalysis has attracted attention as a method for purifying pollutants, but how to simply and efficiently prepare catalyst films with high surface areas is still a challenge. Herein, a chrysanthemum‐like CuO–TiO2–Ag photocatalyst is prepared by anodic oxidation and magnetron sputtering. Scanning electron microscopy and energy dispersive spectrometry analyses show that Ag nanoparticles are uniformly modified on the surface of chrysanthemum‐like CuO–TiO2. Moreover, the influences of the thickness of the TiO2 film and the content of Ag nanoparticles on the degradation of rhodamine B (RhB) are studied by controlling the sputtering time. Among the prepared nanocomposites, the chrysanthemum‐like CuO–TiO2‐2.5‐Ag‐2 proves to have the maximal degradation level with regard to RhB by removing 91.16% RhB after 120 min under UV light. This is because the large surface area offers more active sites. In addition, the trapping experiments show that when CuO–TiO2 is decorated by Ag nanoparticles, this contributes to the movement of a number of photogenerated electrons from the conduction band of TiO2 to Ag, thereby improving the efficiency of charge transfer. The findings reveal that the photodegradation efficiency of the prepared nanocomposites in this study is greatly related to the thickness of the TiO2 film and the content of Ag nanoparticles.

Eco-Friendly Electrodeposition of Al-Zn Alloy from AlCl3-Urea Deep Eutectic Solvent

The electrodeposition of Al-Zn alloy from an aluminium chloride-urea (AlCl3-urea) deep eutectic solvent (DES) containing 0.1 M ZnCl2 near room temperature was investigated. Cyclic voltammetry demonstrates that Al and Zn can be co-deposited, but the presence of Zn(II) restrains the reduction of Al(III). Linear sweep voltammetry reveals that increasing temperature facilitates the reduction of Zn(II) and Al(III), but the promotion effect on the Zn(II) reduction is greater than that on Al(III) reduction. Chronoamperometry analysis indicates that the electrocrystallization of Al-Zn alloy on a glassy carbon electrode follows instantaneous nucleation, which is similar to that of pure Al. SEM shows that the obtained alloy coating is smooth but not compact. With the increase of temperature, the content of Zn in deposits increases, the grain grows up and the microstructure transforms from granular to cluster structure. EDS and XRD analyzes prove that the deposits are pure Al-Zn alloy and composed of α phase and η phase. Tafel polarization test confirms the as-prepared alloy coating with higher Zn content (45 wt%) possesses excellent corrosion resistance. All these findings promise an eco-friendly and simple route to produce the Al-Zn alloy coating with excellent corrosion resistance near room temperature.

Physicochemical study of natural zeolite modified with lavender essential oil

Zeolite-containing nanocomposites as candidates for Lavender oil delivery systems were investigated. The nanocomposite samples and lavender oil delivery systems were investigated by pore size distribution and X-ray diffraction (XRD), the specific surface area with Brunauer-Emmett-Teller (BET), Fourier-transform infrared (FT-IR) spectrometer, energy-dispersive spectroscopy (EDX) analysis and Scanning Electron Microscopy (SEM). These initial results could significantly contribute to the further development of applications for lavender essential oil delivery systems based on natural zeolites as innovative bioactive products.

Investigation into the alkali-activation of lithium slag: A sustainable alternative to conventional cement with optimized mechanical properties

Utilizing lithium slag as a precursor for alkali-activated cementitious materials offers a sustainable alternative to conventional cement, addressing both environmental pollution and land-use challenges posed by lithium slag waste. Additionally, this practice reduces energy consumption and CO2 emissions associated with cement production. This study presents a novel methodology involving high-temperature calcination and mechanical grinding to enhance the reactivity of lithium slag. Analytical techniques, such as X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), were employed to elucidate the mechanisms behind lithium slag's increased reactivity. Subsequently, these activated materials were used to formulate alkali-activated lithium slag cement composites (ALC). Various factors, including the calcination temperature, water-to-cement ratio, NaOH concentration, and lithium slag content, were investigated for their effects on the fluidity and mechanical properties of the mortar. Analytical techniques including XRD, scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), FTIR, and thermogravimetric analysis (TGA)/derivative thermogravimetry (DTG), were used to explore the hydration mechanisms. Results indicate that the optimal calcination temperature for lithium slag was 700 °C, while the optimal NaOH concentration was 1 mol/L. ALC exhibited robust mechanical properties, with compressive, flexural, and fluidity measures reaching 37.66 MPa, 10.13 MPa, and 200 mm, respectively. Predominant hydration products were found to be N-A-S-H and C-A-S-H. The production cost of 1 ton of ALC is $49.8, which is roughly 70% of the cost of producing 1 ton of OPC. Additionally, the total CO2 emissions and energy consumption of producing ALC amount to 60.56% and 64.95% respectively, compared to the total CO2 emissions and energy consumption of producing 1 ton of OPC.

A Facile Synthesis of Bimetallic Copper-Silver Nanocomposite and Their Application in Ascorbic Acid Detection

Background:: An important antioxidant, ascorbic acid, must be detected in several industrial samples collected from food, pharmaceuticals, and water treatment plants. Herein, we reported a method to produce a bimetallic copper-silver (Cu-Ag) nanocomposite and used it in the development of very sensitive and selective electrochemical sensor for the detection of ascorbic acid. Methods:: A simple chemistry concept was used during the synthesis process to reduce the cost while minimizing the use of dangerous chemicals and minimizing the environmental impact. The Strobilanthes kunthiana leaves extract effectively reduced the copper and silver ions, resulting in the creation of an extremely stable and evenly distributed Cu-Ag nanocomposite. Results:: As-prepared bimetallic Cu-Ag nanocomposite exhibited outstanding electrochemical activity against ascorbic acid oxidation. The nanocomposite was examined using field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), elemental mapping (EMap) and X-ray diffraction analysis (XRD) to ascertain its composition, structure, and stability. Using cyclic voltammetry (CV), the electrochemical performance of the nanocomposite and also the detection of ascorbic acid were carried out. The bimetallic Cu-Ag nanocomposite also exhibited better long-term stability and fouling resistance, making it appropriate for use in real-world applications and complex sample matrices. Conclusion:: The bimetallic Cu-Ag nanocomposite coated electrode was used to detect the concentration of ascorbic acid by amperometry. As a result, this study offered a simple chemical method for creating a bimetallic copper-silver nanocomposite with superior electrochemical qualities for the accurate detection of ascorbic acid. conclusion: Its potential use as an electrochemical sensor for the detection of ascorbic acid opens doors for a variety of industries, including biological diagnostics, judging the quality of food, and environmental monitoring. As a result, this study offers a green method for creating a bimetallic copper-silver nanocomposite with superior electrochemical qualities for the accurate detection of ascorbic acid. The created nanocomposite has a lot of potential for improving ascorbic acid detection methods while upholding sustainable material synthesis. other: NA

Electrochemical Behavior of the Oxidative Dissolution of Gold Catalyzed by Lead Ion in Thiourea Solution

ABSTRACT Thiourea is a low-toxicity gold lixiviant that has promise to substitute highly toxic cyanide for gold extraction. The electrochemical behavior of lead ion in the dissolution of gold in thiourea solution was investigated by electrochemical and analytical technique. Electrochemical results suggest that the addition of lead ion (10 mg/L and 20 mg/L) to thiourea solution increased the open circuit potential from 0.31 V to 0.32 V and 0.34 V, respectively, due to the significant increase of cathodic current density. The presence of lead ion could significantly improve the oxidative dissolution of gold and thus resulted in higher gold dissolution in thiourea solution, particularly at higher anodic potentials. The scanning electron microscope (SEM) equipped with energy dispersive spectroscope (EDS) and X-ray photoelectrode spectroscopy (XPS) analyses indicate the improvement of gold dissolution is attributed to the formation of gold-lead (AuPb2) layer on gold surface, which acts as a cathode to promote galvanic corrosion of gold. The possible mechanism is proposed that gold dissolution in thiourea solution with lead ion follows a two-step process: (1) the formation of AuPb2 layer on gold surface and (2) the dissolution of AuPb2 layer under the applied anodic potential.

Enhanced Electrical and Optical Properties of Bismuth Tantalum Oxide Thin Films through Graphene Oxide Doping.

In this study, a hybrid thin film was fabricated by doping graphene oxide in a bismuth tantalum oxide solution in the sol-gel state. The thin film was produced by a brush-coating process. The graphene oxide doping ratios used were 0, 5, and 15 wt %. In the process of producing the thin film, the prepared sol-gel solution generates contraction forces, owing to the shear stress from the bristles of the brush, forming a microgroove structure. This structure was confirmed through atomic force microscopy, transmission electron microscopy, and energy-dispersive spectroscopy analyses. As a result of line profile analysis in atomic force microscopy, the groove heights of the thin film surface at 0, 5, and 15 wt % doping were 110, 130, and 160 nm, respectively, and the width of all grooves was 1 μm. The width of all thin films was approximately 1 μm, and microgrooves were confirmed. Moreover, the hybrid thin-film formation was confirmed by X-ray photoelectron spectroscopy. By comparing the electrical properties of the bismuth tantalum oxide thin film without graphene oxide doping and the thin film doped with 15 wt % graphene oxide, it was demonstrated that the electro-optical properties increased excellently with graphene oxide doping. Typically, the threshold voltage was reduced by approximately 0.26 V. Based on these observations, graphene oxide doped bismuth tantalum oxide hybrid thin films can be considered as promising candidates for thin-film applications in next-generation displays.

Effect of nanoparticle-enhanced biocementation in kaolinite clay by microbially induced calcium carbonate precipitation

Microbially induced calcium carbonate precipitation (MICP) is a nature-based technique that has been developed over the past two decades for soil stabilization. However, the use of MICP for clay stabilization has received limited attention in the literature. On the other hand, the utilization of nanomaterials, such as nano-silica (nano-SiO2), for soil stabilization has been explored in numerous studies in the literature. This paper investigates the effect of nano-CaCO3 and nano-SiO2 on MICP stabilization in kaolinite clay. Nanoparticle-enhanced bio-cementation is introduced to effectively improve the strength of kaolinite clay at high water contents. Unconfined compressive strength (UCS) tests were conducted to evaluate the impact of the nano-bio-treatment (mixture of nano-additives and MICP) on soil strength. Additionally, the microstructure of the treated soils was examined using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, and X-ray diffraction (XRD) analyses. The results indicate that the MICP stabilization method is effective in enhancing the strength of kaolinite soil through a mixing approach. The study of UCS in the treated samples revealed that the use of nano-CaCO3 and nano-SiO2 can have either detrimental or beneficial effects on the MICP method, depending on the degree of saturation of the treated samples. The highest UCS observed for the MICP method at a target water content of 0.25 was more than three times that of untreated soil at the same moisture content. Furthermore, the increase in UCS for the samples treated with MICP was 2.5 times that of the untreated soil at a 30% target water content. The most significant finding, however, is that, at a 30% target water content, the samples improved with MICP+ 1.5% nano − SiO2 exhibited UCS values that were six and fifteen times greater than those of the untreated and MIC-treated samples, respectively. SEM images illustrated that the addition of nano-SiO2 with the MICP method led to an agglomerated soil texture, and the formation of calcium carbonate attached to the clay minerals. This results in an increase in soil strength.

Development of the nickel foam supported hydrothermally grown binder-free and highly porous magnesium-cobalt hydroxide films for supercapacitor application

Binder-free electrode synthesis has recently emerged as the superior choice for supercapacitor applications, offering excellent electrochemical properties, better adherency, large stability, as well as low resistance. The present study focused on innovative synthesis of novel binder-free films of MgCo LDH layered double hydroxide (MgCo LDH) nanoflakes by hydrothermal method on Ni-foam. The effect of different reaction times on the structural, morphological, and electrochemical properties of MgCo LDH films are systematically examined. The nanocrystalline nature of MgCo LDH films having interconnected nanoflakes is observed from structural and morphological studies. The redox entities inside the MgCo LDH nanoflakes are identified by energy dispersive spectroscopy and X-ray photoelectron spectroscopy analysis. The electrochemical study is performed in 1 M KOH in which the MgCo LDH deposited at 12 h reaction time showed better aerial capacitance of 2311.9 mF/cm2 and gravimetric capacitance of 1431.21 F/g at 6 mA/cm2. Additionally, the highest energy density of 180 Wh/cm2 is achieved at 1730 W/cm2 power density, with an 89 % coulombic efficiency. Notably, the MgCo LDH film has exhibited outstanding cycling stability, maintaining 75 % capacitance retention over 5000 charging-discharging cycles. These outcomes demonstrated the advantages of the binder-free synthesis of novel MgCo LDH films for supercapacitors and suggest that MgCo LDH is a promising electrode material for real-time supercapacitor application.

A phenomenological constitutive model of Novel Rheo Gravity Die Cast Al-15Mg2Si-4.5Si-0.01Sr-0.015B composite

The present study discusses the high temperature deformation behaviour as well as phenomenological constitutive model development of the novel Rheo gravity die cast (RGDC) Al-15Mg2Si-4.5Si-0.01 Sr-0.015B composite. Within the scope of the study, uniaxial isothermal compression tests are performed on the RGDC Al-15Mg2Si-4.5Si-0.01 Sr-0.015B composite, covering a range of strain rates from 10−3 to 10 s−1 and deformation temperatures spanning from 250 °C to 450 °C. Analysis using X-ray Diffraction (XRD), Energy dispersive spectroscopy (EDS) and Electron Probe Micro Analyzer (EPMA) revealed the presence of distinct phases within the material, including primary Al, Mg2Si, and elemental Si. The study employed three different constitutive models i.e., the Johnson-Cook (JC), modified Johnson-Cook (mJC), and sine hyperbolic Arrhenius (shA) types, to predict the flow stress of the material as a function of strain, strain rate, and deformation temperature. The results indicated that the sine hyperbolic Arrhenius type model and the modified Johnson Cook model effectively accounted the coupling effect of strain, strain rate, and deformation temperature, which affect the flow stress. Statistical analysis, specifically Pearson coefficient correlation (R), average absolute relative error (AARE) and standard deviations, established a reasonable agreement between the predicted flow stress values and the experimental flow stress data. Furthermore, it is observed that the sine hyperbolic Arrhenius type model exhibited superior accuracy compared to the modified Johnson Cook model, particularly at higher strain levels.

Accelerated carbonation of waste paper fly ash by liquid process (NaHCO3) for stabilization of Ba and Pb

The increase of energy valorization of paper sludge waste and biomass due to their high calorific value by incineration leads to an increase of waste paper fly ash (WPFA) quantities, which are in most cases considered as hazardous, and must be dealt with accordingly. The Alternative options for the management of WPFA, such as stabilization/solidification, vitrification or sintering, are not fully developed or either costly. In the present study, accelerated carbonation technology was used to reduce the hazardous nature of WPFA by improving the stabilization of metallic and metalloids trace elements (MMTE), especially Barium (Ba) and Lead (Pb) leaching. The accelerated carbonation of WPFA was found to be optimal at a water/solid ratio of 0.3 L/kg under controlled temperature and humidity conditions. The use of water saturated with 25% sodium bicarbonate (NaHCO3) improved the carbonation of WPFA and the stabilization of Ba and Pb. Batch leaching tests based on thermodynamic equilibrium was used to evaluate the solubility of the MMTE as a function of pH and at the natural pH of non‑carbonated and carbonated WPFA. Thermogravimetry, X-ray diffraction, scanning electron microscopes and energy dispersive spectroscopy analyses were performed to investigate the evolution of carbonation over time and its effect on the chemical and mineralogical properties of WPFA. After 30 days of accelerated carbonation, the leaching concentration of Ba and Pb was below the French legal limit. The leaching concentration of Ba and Pb from carbonated samples decreased 99% and 99.5% respectively. The leaching and release potential behavior of carbonated WPFA were further evaluated using the four-step sequential extraction procedure proposed by the Commission of the European Communities Bureau of Reference (BCR). The speciation of MMTE underwent significant transformation, shifting predominantly from the soluble fraction to the carbonated fraction as a result of the carbonation reaction.

MECHANICAL STIMULATION OF PIEZOELECTRIC SCAFFOLDS PROMOTES CELL OSTEOGENIC DIFFERENTIATION

Bone is a dynamic tissue that undergoes continuous mechanical forces. Mechanical stimuli applied on scaffolds resembling a part of the human bone tissue affects the osteogenesis [1]. Poly(3,4-ethylenedioxythiophene) (PEDOT) is a piezoelectric material that responds to mechanical stimulation producing an electrical signal, which in turn promotes the osteogenic differentiation of bone-forming cells by opening voltage-gated calcium channels [2]. In this study we examined the biological behavior of pre-osteoblastic cells seeded onto lyophilized piezoelectric PEDOT-containing scaffolds applying uniaxial compression.Two different concentrations of PEDOT (0.10 and 0.15% w/v) were combined with a 5% w/v poly(vinyl alcohol) (PVA) and 5% w/v gelatin, casted into wells, freeze dried and crosslinked with 2% v/v (3-glycidyloxypropyl)trimethoxysilane and 0.025% w/v glutaraldehyde. The scaffolds were physicochemically characterized by FTIR, measurement of the elastic modulus, swelling ratio and degradation rate. The cell-loaded scaffolds were subjected to uniaxial compression with a frequency of 1 Hz and a strain of 10% for 1 h every second day for 21 days. The loading parameters were selected to resemble the in vivo loading situation [3]. Cell viability and morphology on the PEDOT/PVA/gelatin scaffolds was determined. The alkaline phosphatase (ALP) activity, the collagen and calcium production were determined.The elastic modulus of PEDOT/PVA/gelatin scaffolds ranged between 1 and 5 MPa. The degradation rate indicates a mass loss of 15% after 21 days. The cell viability assessment displays excellent biocompatibility, while SEM images display well-spread cells. The ALP activity at days 3, 7 and 18 as well as the calcium production are higher in the dynamic culture compared to the static one. Moreover, energy dispersive spectroscopy analysis revealed the presence of calcium phosphate in the extracellular matrix after 14 days. The results demonstrate that PEDOT/PVA/gelatin scaffolds promote the adhesion, proliferation, and osteogenic differentiation of pre-osteoblastic cells under mechanical stimulation, thus favoring bone regeneration.

Phase Transition of Thermally Treated Polyhedral Nano Nickel Oxide with Reduced Band Gap

Nickel oxide (NiO) is a semiconducting material which exhibits a unique electronic structure. Because of its distinctive electronic properties, NiO stands as an intriguing candidate for various applications in optoelectronics, photo catalysis, and energy devices such as solar cells. In the present work efforts have been made to tailor the band gap of NiO. A simple co-precipitation method followed by heat treatment is utilized to synthesize the material. Prior to heat treatment, x-ray diffraction study of the as synthesized material showed the presence of nickel hydroxide [Ni(OH)2]. On calcination for one hour at 1000oC, a single phase NiO wasrevealed. After heat treatment it was noticed that the particle size was found to be increased. The absorption spectra of [Ni(OH)2] and NiO were recorded using UV-Vis spectroscopy method. Using Tauc plot a band gap of 4.2 eV and 1.8 eV for Ni(OH)2 and NiO was observed respectively. It is observed that a significant decrease in band gap of NiO was noticed. Surface morphological study was carried out by using FESEM, which revealed the transformation of sheet like structures of [Ni(OH)2] to polyhedral shaped NiO on calcination. The presence of nickel and oxygen was confirmed by the energy dispersive spectrometry analysis.

In situ observation of thermal-driven structural transitions of a β-NaYF4 single nanoparticle aided with correlative cathodoluminescence electron microscopy.

NaYF4 systems have been widely studied as up-conversion host matrices, and their phase transitions are flexible and worth investigating in great detail. Herein, the evolution of morphology and crystal structure of a Eu3+-doped β-NaYF4 single nanoparticle heated in an air atmosphere was investigated using in situ transmission electron microscopy (TEM). The annealing process revealed that the hexagonal β-NaYF4 phase undergoes sequential transformations into high-temperature cubic phases at both 350 °C and 500 °C. The emission characteristics of Eu3+ in the single nanoparticle after heating treatment were also analyzed using Correlative Cathodoluminescence Electron Microscopy (CCLEM). The results of CCLEM suggest a gradual decrease followed by a subsequent increase in structural symmetry. A comprehensive spectroscopic and structural analysis encapsulates the entire transformation process as NaYF4 → YOF → Y2O3. In situ energy dispersive spectroscopy analyses (EDS) support this reaction process. The aforementioned technique yields correlative lattice-resolved TEM images and nanoscale spectroscopic information, which can be employed to assess the structure-function relationships on the nanoscale.

Influence of magnesium treatment on inclusions and primary carbides in As-cast H13 die steel

In this study, the inclusions and primary carbides in H13 hot-work tool steel were investigated, both with and without magnesium treatment, utilizing various analytical techniques such as optical microscope (OM), scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and quantitative analysis methods. Furthermore, the experimental results were compared with the calculations obtained from Thermo-Calc software. The results revealed that as we move from the edge to the center of the steel, the equivalent diame-ter of inclusions increased. However, upon adding magnesium to the steel, the size of inclusions decreased, while the number of inclusions per unit area increased. The primary carbides found in H13 steel consisted of vanadium-rich MC carbides and molybdenum-chromium-rich M2C carbides. The addition of magnesium had a significant impact on the size of these primary carbides. The presence of MgAl2O4 particles acted as heterogeneous nuclei, providing nucleation sites that induced smaller sizes and more uniform distribution of primary carbides. Furthermore, it was observed that the banded segregation in the annealed microstructure became more uniform after magnesium treatment, leading to an improvement in the banded segregation.