Energy Dispersive X-ray Research Articles

Performance evaluation of M25 grade concrete with and without replacement of cinder aggregate: an extensive experimental investigation

The global demand for cement and concrete is expected to rise by 2.4 to 3.0% annually, reaching around 4.8 billion metric tons. Current materials are insufficient to meet this demand, necessitating alternative aggregates that balance environmental impact, sustainability, economic benefits, and maintain strength and durability. Therefore, this paper is attempted to replace natural coarse aggregate (NCA) in M25 grade concrete with cinder coarse aggregate (CCA) in varying replacement proportions of 0% to 100%. The mechanical (compressive, split tensile and flexural strength) and durability (fire resistance, water absorption, and chloride ion penetration) characteristics are evaluated in order to determine the appropriate replacement percentage of cinder aggregate. Investigations have also been conducted to examine the microstructural characteristics of sustainable concrete specimens under electron scanning microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffractometry (XRD). The findings of these investigation shows that the strength properties continuously declines with the continuous replacement of CCA, but however the targeted mean strength of M25-grade concrete is still attained for all the replacement proportions. Durability characteristics improved with higher CCA content. The cost analysis for 1 m³ of sustainable concrete with CCA showed it to be quite feasible compared to conventional concrete.

Characterisation and visible light induced antibacterial activity of Cu-doped zinc oxide nanoparticles

ABSTRACT Zinc oxide particles doped with copper were produced using a cost-effective sol-gel approach at a temperature of 80°C. The process involved combining Zn(NO3)2, Cu(NO3)2, and citrate precursors. A variety of analytical techniques, including scanning electron microscopy, Energy-dispersive X-ray spectroscopy (EDX), diffuse reflectance spectroscopy (UV-Vis DRS), and energy dispersive X-ray diffraction spectroscopy (XRD), were employed to study the physical and chemical characteristics of the nanoparticles. The addition of copper resulted in a significant decrease in the size of wurtzite ZnO nanoparticles, reducing from 180 nm for undoped ZnO to 133 and 40 nm for 10% Cu-doped and 25% Cu-doped ZnO, respectively. The absorption spectra displayed a gradual shift towards the visible range as the concentration of copper in the ZnO particles increased. The calculated band gaps for the various samples were determined to be 3.1 eV for undoped ZnO, 2.3 eV and for 10% Cu-doped ZnO, and 1.8 eV for 25% Cu-doped ZnO. The antibacterial efficacy of Cu-doped ZnO was observed to be significantly greater than that of the undoped sample. Additionally, it demonstrated antibacterial activity under visible light conditions, which suggests the successful synthesis of zinc oxide particles that are induced by visible light.

Construction of a hydrazine electrochemical sensor using Ag@ZIF as the electrode material.

In recent years, the fabrication of hydrazine sensors has received extensive attention because of the toxicity of hydrazine to the environment and human beings. It is thus important to design and develop efficient electrode modifiers for the construction of hydrazine electrochemical sensors. Herein, we reported the benign synthesis of a silver (Ag)-doped zinc-based zeolitic imidazolate framework (ZIF-8). The synthesized Ag@ZIF-8 was characterized by various advanced physiochemical characterization methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). A screen-printed electrode (SPE) was modified with the prepared Ag@ZIF-8. The cyclic voltammetry (CV) and linear sweep voltammetry (LSV) methods were used for assessing its sensing towards hydrazine. The obtained results showed a reasonable detection limit (0.1 μM), sensitivity (1.98 μA μM cm-2), stability, selectivity, and repeatability using Ag@ZIF-8/SPE as a hydrazine sensor. The real-sample investigations demonstrated recovery rates of 96-97%.

Electrochemical Detection of Miltefosine in Urine Using Amino Functionalised Multi-walled Carbon Nanotubes and [Fe(CN)6]−3/−4 as a Redox Couple

Abstract Miltefosine is an alkyllylosophospholipid analogue used to treat visceral leishmaniasis. Recently, reports have been made of suspected counterfeit miltefosine on the Indian market. With the risk counterfeit drugs pose to drug resistance development, quality control of antileishmanial drugs has become important. Hence, in this study, amino-functionalized multi-walled carbon nanotubes (MWCNT-NH2) were synthesised and characterised using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Also, electrochemical impedance spectroscopy and cyclic voltammetry were used to study the electrochemical properties of the synthesised MWCNT-NH2. A complex was formed between MWCNT-NH2 and miltefosine (Mil-MWCNT-NH2). Five microliters of Mil-MWCNT-NH2 was drop-cast on glassy carbon electrode, and differential pulse voltammetry studies were carried out to assess the performance of the sensor. Using [Fe(CN)6]-3/-4 as a redox couple, a calibration study was carried out at different concentrations (0–250 µM) to establish the concentration range of the sensor. A linear response was established. With a detection limit of 1 µM, the fabricated sensor is a viable tool for detecting antileishmanial drug miltefosine in urine samples and possible application in quality control of miltefosine against counterfeiting. Graphical Abstract

Water hyacinth biomass-based biochar: Preparation and characterizations for sustainable soil amendment

AbstractThis study investigates the utilization of biochar (WHBC) from water hyacinth biomass (WHBM) for sustainable soil amendment to improve soil quality. WHBM and WHBC are prepared and characterized with thermogravimetric analysis (TGA). For that, physiochemical, proximate, ultimate, and elemental analyses are done and characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDAX) to identify the suitability of soil amendment. WH biomass is carbonized with a limited air supply in a muffle furnace, and the study found that 300–664 °C temperature is the optimum condition for producing biochar from TGA. XRD of WHBC displayed more crystallinity than WHBM. FTIR of WHBC showed higher carbon stability increment than WHBM. The SEM micrograph of WHBM showed that compact, and fibril structures and WHBC revealed macroscopic changes that can significantly improve the soil properties. EDAX analysis of WHBM and WHBC proved that various soil nutrients can be helpful for plant growth. The study shows that WHBM can be utilized as a soil quality amendment material by converting it to biochar and an effective material for carbon storage in soils.

Highly tunning of dielectric and photocatalytic properties of crystalline ZnO semiconductor: Functionality of Ba additives

Abstract In the present work, the concentration of Ba-additive played a significant role in advancing the dielectric properties and photo-removal activity of ZnO semiconductor for methylene blue dye. Ba doped ZnO semiconductor with different doping concentrations (Zn1-xBaxO, x = 0.003, 0.005, 0.007 and 0.009 wt.%) were grown by solid-state reaction route. The X-ray diffraction (XRD) data confirmed the formation of the wurtzite structure of ZnO along with the presence of BaO-based secondary phase (SP). The XRD peak intensity related to the SP was found to increase with the increase of Ba concentration. Microstructural analyses through scanning electron microscope (SEM) images and energy-dispersive X-ray analysis (EDS) showed that with the addition of Ba, a gradual increase in the grain size was observed. Furthermore, SP segregated at the grain boundary and showed an increasing trend with doping. The emergence of secondary phases with Ba concentration was confirmed with the help of supplementary spectroscopic characterizations including Fourier transform infrared spectroscopy (FTIR) and UV-Vis diffuse reflectance. The presence of BaO secondary phase has shown a benefit effect on the dielectric and photodegradation properties of ZnO material. The remarkable resistance reduction suggested that the higher Ba concentrations significantly enhance charge carrier mobility. For wastewater treatment uses, BZO9 photocatalyst exhibited a perfect degradation efficiency of 90.1% for methylene blue (MB) removal after 210 min of visible light illumination.

Microscopic Characterization Based Synthesis of Silver Nanoparticles Using Merremia quinquefolia (L.) Hallier f. Leaf Extract: Their Biological Approaches and Degradation of Methylene Blue Dye.

The green methods for the synthesis of silver nanoparticles (AgNPs) has developed popularity recently due to the low preparation costs, environmental friendliness, and non-toxicity of the precursors. In this study, AgNPs were synthesized using leaf extract from Merremia quinquefolia. Spectroscopic techniques were used for analyzing the functional groups, morphology, crystalline phase, and elemental composition of nanomaterials. The ultraviolet (UV) visible spectrometry absorption spectra of the AgNPs had a surface plasmon resonance band at 459 nm and Fourier transformed infrared spectrum (FTIR) analysis showed the presence of elements groups. X-ray diffraction (XRD) analysis indicates the crystalline structure and the energy-dispersive x-ray spectroscopy (EDAX) analysis shows strong signals for the silver element. Morphological analysis using transmission electron microscope (TEM) and scanning electron microscopy (SEM) analyses revealed that the AgNPs exhibited spherical shapes with an average size of 14 nm. Furthermore, it was indicated by the Raman spectra vibrational peak at 240 and 470 cm-1. The disk diffusion method showed that AgNPs were highly effective in inhibition of Gram-positive bacteria Staphylococcus aureus with a high inhibitory zone (14 ± 0.23 mm). Antioxidant activity, the IC50 values for assays DPPH (145.7 μg/mL) and ABTS (112.09 μg/mL), and albumin denaturation in human red blood cells showed higher anti-inflammatory activity. AgNPs had an IC50 value of 4.62 μg/mL against breast cancer (MCF-7) cells. Methylene blue (MB) degrading studies were used to assess the photocatalytic activity of AgNPs. They are at 240 min observed sunlight, the MB degradation efficiency was 94.89%. Overall, although M. quinquefolia synthesizes AgNPs for environmentally friendly applications, the study is indicated to fully understand the potential involved in treating breast cancer cells.

Methanol-Tolerant Pd-Co Alloy Nanoparticles on Reduced Graphene Oxide as Cathode Catalyst for Oxygen Reduction in Fuel Cells

The design of efficient and cost-effective electrocatalysts to replace Pt in an oxygen reduction reaction (ORR) is crucial for advancing proton exchange membrane fuel cell (PEMFC) technologies. This study synthesized Pd-Co bimetallic alloy nanoparticles supported on reduced graphene oxide (rGO) through a simple chemical-reduction method, making it suitable for low-cost, large-scale fabrication and significantly reducing the need for Pt. The nanostructures were systematically characterized using various analytical techniques, including X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDX), and cyclic voltammetry (CV). Electrochemical investigations revealed that the Pd-Co/rGO catalyst exhibits remarkable ORR performance in an alkaline environment, with an electrode-area-normalized activity rivaling that of the commercial Pt/C catalyst. Remarkably, Pd-Co/rGO demonstrated an onset potential (Eonset) of 0.944 V (vs. RHE) and a half-wave potential (E1/2) of 0.782 V (vs. RHE), highlighting its excellent ORR activity. Furthermore, the Pd-Co/rGO catalyst displayed superior methanol-tolerant ORR activity, outperforming Pt/C and monometallic Pd/rGO and Co/rGO systems. The enhanced electrocatalytic performance is attributed to the smallest size, consistent shape, and good dispersion of the alloy structure on the RGO surface. These findings establish Pd-Co/rGO as a promising alternative to Pt-based catalysts, addressing key challenges such as methanol crossover while advancing PEMFC technology in alkaline media.

Influence of elevated temperature exposure on the residual compressive strength and radiation shielding efficiency of ordinary concrete incorporating granodiorite and ceramic powders

This research investigates the potential of utilizing types of construction waste as partial cement replacements within concrete formulations. Notably, granodiorite and ceramic powders were introduced at varying substitution ratios. The impact of these waste materials on the compressive strength and radiation shielding effectiveness of traditional concrete was evaluated under both ambient and elevated temperature conditions. Additionally, several microstructural tests like X-ray diffraction (XRD), Thermogravimetric analysis (TGA), and Energy dispersive X-ray (EDX) were conducted to assess the influence of using the optimal replacement ratios of the investigated waste powders on the studied properties of concrete. Results revealed a substantial improvement in the investigated properties of the concrete. Remarkably, a 7% substitution with waste granodiorite powder (WGDP) yielded the optimal mix for compressive strength, exhibiting increases of 24.7%, 26.1%, 22%, and 28% at room temperature, 400 °C, 600 °C, and 800 °C, respectively. Likewise, a 7% replacement with waste ceramic powder (WCP) exhibited quantifiable improvements in compressive strength, with approximately 23.1%, 23.5%, 25.6%, and 32.6% at room temperature, 400 °C, 600 °C, and 800 °C, respectively. For microstructure analysis, XRD analysis confirmed enhanced pozzolanic activity with reduced portlandite and increased calcium silicate hydrate (CSH) formation for the optimal WGDP and WCP mixes compared to the control mix. TGA analysis revealed higher CSH decomposition in modified mixes, indicating greater pozzolanic reaction. Furthermore, density and EDX analyses showed denser microstructures in waste powders-incorporated mixes due to finer particle packing and secondary hydration effect. The radiation shielding investigation show that the optimum WCP mix (C7) enhances the attenuation capability of concrete. The optimum WGP mix (GD7) also contributes positively to attenuation, though to a lesser extent than C7. Ordinary concrete (CO) exhibits the lowest LAC, indicating its baseline performance in linear attenuation. Thus, the studied CM-concrete samples provide the best protection against fast neutrons which pave the way for the utilization of industrial waste, especially ceramic and granodiorite waste, in enhancing the properties of concrete towards radiation shielding against gamma rays and neutrons.

Application of a New Carbon Black Filler in SBR Composites

The microstructure and properties of a new type of carbon black produced by a domestic company through a new process were systematically characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, and X-ray diffraction (XRD). The vulcanization properties, mechanical properties, and electrical conductivity of the new carbon black with different filler amounts were investigated in styrene butadiene rubberstyrene–butadiene rubber (SBR), using the traditional reinforcing filler N660 carbon black as a control. The experimental results demonstrate that the new carbon black exhibits a stratified structure with a specific surface area of 345.96 m2/g, and its particle size distribution is primarily concentrated within the 0.1–1 μm range. When the filling ratio was 30 phr/100 phr, the tensile strength of SBR composites filled with the new carbon black increased by 12.3% and the tear strength increased by 9.6% compared with those filled with N660 carbon black. In summary, the new carbon black can significantly improve the comprehensive performance of SBR composites and reduce the production cost. This provides a new type of material for the rubber industry that takes into account both economy and performance while also providing reference data for basic research in the field of SBR.

Enhanced photocatalytic degradation of Rhodamine B using polyaniline-coated XTiO3(X = Co, Ni) nanocomposites

In this study, novel polyaniline-coated perovskite nanocomposites (PANI@CoTiO3 and PANI@NiTiO3) were synthesized using an in situ oxidative polymerization method and evaluated for the photocatalytic degradation of Rhodamine B (RhB) a persistent organic pollutant. The nanocomposites displayed significantly enhanced photocatalytic efficiency compared to pure perovskites. The 1%wt PANI@NiTiO3 achieved an impressive 94% degradation of RhB under visible light after 180 min, while 1wt.% PANI@CoTiO3 reached 87% degradation under UV light in the same duration. X-ray diffraction (XRD) confirmed that the crystalline structures of CoTiO3 and NiTiO3 remained intact post-polymerization. At the same time, Fourier transform infrared spectroscopy (FTIR) verified the successful deposition of PANI through characteristic functional group vibrations. Diffuse reflectance spectroscopy (DRS) revealed reduced band gaps of 2.63 eV for 1wt.% PANI@NiTiO3 and 2.46 eV for 1wt.% PANI@CoTiO3, enhancing light absorption across UV and visible ranges. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis demonstrated the uniform distribution of PANI, ensuring consistent surface activity and efficient charge transfer. The photocatalytic test confirmed a pseudo-first-order degradation mechanism. The study elucidates the degradation mechanism through intermediate identification via HPLC-MS analysis, highlighting N-de-ethylation, aromatic ring cleavage and eventual mineralization into CO2 and H2O as critical pathways. Furthermore, the 1wt.%PANI@NiTiO3 nanocomposite demonstrated excellent stability and recyclability, maintaining its degradation efficiency over four consecutive cycles with minimal change. These findings highlight the potential of PANI@XTiO3 nanocomposites for sustainable and efficient wastewater treatment, addressing diverse environmental challenges by tailoring photocatalysts to specific light sources.

The study of pure and Ni Doped CdO nanoparticles to explore their Antimicrobial Activity

This study focuses on the synthesis of Cadmium oxide (CdO) nanoparticles with doped transition metals like Nickel (Ni) of varying concentrations using sol gel citrate synthesis. Chemical and elemental characterization was carried out with X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible (UV-Vis) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS). The efficacy of antimicrobial properties of the synthesized nanoparticles against a wide range of Gram-positive and Gram-negative bacterial strains and fungal strains was explored. The results demonstrates that the doping of transition metals enhances the antibacterial and antifungal properties of the CdO nanoparticles and thus it can be used as antimicrobial agent in various industrial and medical fields due to its potential strength.

Mangifera indica–driven CuO nanoparticles: properties for sensing and optoelectronics

This study reports biological synthesis of Mangifera indica leaf extract–mediated copper oxide nanoparticles (CuO NPs). CuO NPs are characterized for crystal structure and crystallite size determination, absorption peak, particle size and morphological analysis, elemental composition, and functional groups’ identification using X-ray diffraction (XRD), ultraviolet–visible spectroscopy, high-resolution transmission electron microscope (HRTEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), and Fourier transform infrared (FTIR). NPs show an absorption peak ∼338 nm and Tauc’s plot gives band gap energy ∼2.2 eV. XRD pattern depicts monoclinic phase ∼18 nm average crystallite size NPs. FESEM and HRTEM micrographs confirm the needle-shaped NPs having 5:40 nm aspect ratio. The EDS spectrum, depicting the Cu and O peaks, shows that the particles are free from any type of impurity. FTIR analysis elucidates the role of bioactive chemicals in the extract in the successful formation of NPs. The photoluminescence study reveals the existence of violet, green, orange, yellow, and red emission bands. Also, NPs exhibit an electrical conductivity of 1.37 × 10–7 S/m and 5. 31 × 10–7 S/m at 100°C and 200°C. Thus, environmentally friendly, non-toxic, green-synthesized CuO NPs hold significant potential for applications in resistive sensors, solar cells, and optoelectronics devices.

Fabrication and multi-aspect characterization of polymer composite reinforced with differently stacked flax-fiber and steel-wire meshes

This study focuses on developing a new type of multi-fiber reinforced multi-layer polymer composite using natural and metal fibers. Flax fiber has shown potential as a fairly good reinforcement, but its mechanical weaknesses have led researchers to explore hybridization in composites for better performance. The paper reports on the fabrication and characterization of a unique kind of hybrid composite that uses the advantages of stainless steel along with flax fiber, resulting in a lightweight material suitable for engineering uses. In this research, SS-304 wire mesh is used along with flax fibers to make three different composites, with varying stacking arrangements. Experimental results indicate that, although the inclusion of steel wire mesh slightly reduces interlaminar shear strength, significant improvements are observed in tensile strength, flexural strength, hardness and impact resistance. Stereo-microscopy is utilized to analyze surface features and stacking sequences, while scanning electron microscopy (SEM) reveals fracture surfaces in tensile and flexural specimens. Energy-dispersive X-ray spectroscopy (EDX) mapping helps to identify the elemental compositions present in the composites. This study demonstrates that metal reinforcement can enhance the mechanical properties of flax-reinforced polymer composites, providing a lightweight and sustainable solution for engineering applications.

Towards Solid-State Batteries Using a Calcium Hydridoborate Electrolyte.

Solid-state batteries created from abundant elements, such as calcium, may pave the way for cheaper and safer electrical energy storage. Here we report a new type of solid calcium hydridoborate electrolyte, Ca(BH4)2·2NH2CH3, with a high ionic conductivity of σ(Ca2+) ~ 10-5 S cm-1 at T = 70 °C, which is assigned to a relatively open and flexible structure with apolar moieties and weak dihydrogen bonds that facilitate migration of Ca2+ ions in the solid state. The compound display a low electronic conductivity, providing an ionic transport number close to unity (tion = 0.9916). Calcium plating is observed for a Ca|Ca(BH4)2·2NH2CH3|Pt electrochemical cell and the electrodes are investigated using scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) that reveal a rugged Ca anode surface owing to the stripping process and the presence of Ca-containing domains on the Pt working electrode from the plating process. Improved electrochemical reversiblity was achieved in a three-electrode cell configuration using a CaxSn counter and reference electrode and a Sn working electrode, CaxSn|Ca(BH4)2·2NH2CH3|Sn, providing reversible Ca plating and stripping.

Sustainability metrics targeted optimization and electric discharge process modelling by neural networks

Aluminium and its alloys, especially Al6061, have gathered significant interest among researchers due to its less density, great durability, and high strength. Due to their lightweight properties, the precise machining of these alloys can become expensive through conventional machining operations for intricate products. Therefore, non-traditional machining such as electric discharge machining (EDM) can potentially be opted for the cutting of Al6061. EDM is often criticized due to its low machining rates, therefore, in the current work, cryogenic treatment (CT) has been performed on the brass electrode to evaluate the improvement in the machining rates. In addition, kerosene oil (KO) has been engaged in traditional EDM which is replaced with the deionized water (DI) based dielectric as a sustainable alternative. The machining variables such as spark voltage (SV), pulse-on-time (PON), peak current (IP), and Al2O3 powder concentration (CP) have been chosen to determine the material removal rate (MRR), surface roughness (SR), and specific energy consumption (SEC) while comparing non-treated (NT), and cryogenically treated (CT) brass electrodes during EDM. The results were analyzed through optical micrographs, scanning electron microscopy (SEM) analysis, energy dispersive x-ray (EDX) examination, and 3D surface plots. An artificial neural network (ANN) has been constructed for the better prediction of output responses. Moreover, multi-response optimization through the non-dominated sorting genetic algorithm (NSGA-II) has also been performed. The magnitudes of MRRCT, SRCT, and SECCT obtained by multi-response optimization are 64.82%, 27.45%, and 46.60% are better than the values obtained by un-optimized settings of CT brass electrodes. However, the optimal magnitudes of processing parameters are IP = 24.85 A, SV = 2.18 V, PON = 119.11 µs, and CP = 1.05 g/100 ml.

A Semi-Automated Machine-Learning Tool for Assessing Building Phases: Discriminant Analysis of Mortars from the 2022 Excavation at the Sarno Bath Complex in Pompeii

This study presents the results of the analyses of 15 structural mortars from the building at civ. 21, level +0 of the Sarno Bath complex in Pompeii. These samples were collected during recent stratigraphic excavations (year 2022) for detailed in-laboratory compositional characterization, aiming to trace the construction phases of the originating walls. The 2022 samples were firstly analyzed via quantitative phase analysis–X-ray powder diffraction. The resulting quantitative mineralogical profiles were then processed alongside those analyzed in previous studies from level +0 structures of the Sarno Baths using multivariate statistical methods, including principal component analysis (PCA) and discriminant analysis, applied to quantitative phase analysis (QPA)–X-ray powder diffraction data (XRPD), to identify and map the construction phases. This approach enabled the correlation of the 2022 samples with previously established construction phases. Polarized-light optical microscopy and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) were then primarily used for validation purposes. These methods highlighted the compositional differences between samples and revealed significant features related to the use of specific raw materials. These results confirm the reliability of the semi-automated sample processing proposed in this research, adopting discriminant analysis as a machine-learning-based tool for defining construction phases in Pompeian contexts.

Evaluation by Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy of the Effects of Root Canal Instrumentation on the Radicular Dentine.

One area of technological advancement has been the shift from stainless steel hand tools to nickel-titanium (Ni-Ti) rotary tools. This paper aims to perform an invitro comparative study to evaluate the efficacy of five endodontic manual and rotary instruments such as Kerr files, Orodeka Plex V, ProTaper Flydent NiTi super files, and ProTaper Flydent NiTi super files in combination with an ultrasonic endodontic E3D Diamantata EMS scaler used for root canal shaping. The following aspects were highlighted: effective removal of smear layer (SL) from the dentinal tubules in the coronal 1/3, middle 1/3, and apical 1/3 of the root canal, appearance of cracks in the dentinal walls by SEM analysis, and highlighting of dentin mineral content and remnant debris by EDX analysis. In the study, 48 monoradicular, uninjured teeth were taken and divided into four groups, each with 12 teeth to be canal modeled, then longitudinally sectioned; the active surface was metallized for SEM-EDX analysis. From the SEM micrograph analysis, the morphology of the crystallites, the distribution of SL components, and the highlighting of instrumentation path traces/amplitudes were observed. By analyzing the SEM photomicrographs at 750 and 800× magnification, it was possible to highlight the cracks in the root dentinal walls. Thus, in comparison with Lots I and II which did not present cracks, in Lot III multiple cracks of the root dentinal walls were identified, especially in the coronal 1/3, and in Lot IV cracks were present with preponderance in the coronal and apical 1/3 of the root canals. The EDX images with atom mapping show very well the rather homogeneous elemental distribution for Ca, N, and P, respectively inhomogeneous for Na, Ca, Si, C, N, O, and P elements, as a result of the presence of remnant products from the processing of the root dentinal walls. Root canal instrumentation performed with both manual Kerr needle instrumentation by a convection technique and the rotary, Orodeka system, by crown-down technique, resulted in minimal SL formation in all three root canal areas, unlike the ProTaper FlyDent system. Most cracks were recorded in the case of the ProTaper Flydent rotary instruments and the one in which it was paired with a diamond ultrasonic scaler. The occurrence of dentinal cracks causes a decrease in dentinal microhardness, favoring the occurrence of root fractures.

Electrochemical and surface morphology characterizations of zinc electroplated coatings

Acid baths containing sulfate still lack industrial purposes, although they are classified as low toxicity and represent smaller risks to the environment and operators when compared to the traditional alkaline baths. So, the influence of zinc concentration (Zn2+), current density ( i), temperature ( T), and pH levels were examined during the Zn electroplating process in sulfate baths over process efficiency, coating morphology, and corrosion resistance. The current efficiency decreased as decreasing i (from 30.5 mA/cm2 to 7.5 mA/cm2). Increasing both Zn2+ and T promoted a reduction in the average grain size with nodules structures spread over the coating surface as shown by scanning electron microscope (SEM) analysis. Increasing the bath acidity resulted in a higher roughness profile and a more fragile coating, while the substrate was not completely covered at low i as shown by energy-dispersive x-ray spectroscopy (EDS) analysis. As expected, two capacitive arcs were observed in the electrochemical impedance spectroscopy (EIS) test. Therefore, among the completely covered samples, the conditions Zn2+ = 50 g/L, 30.5 mA/cm2, 50 °C, and pH = 2.5 presented greater deposit homogeneity, grain refinement and increased impedance modulus (2850.26 Ω.cm2 at 30 mHz).

Elastomeric Biocomposites of Natural Rubber Containing Biosynthesized Zinc Oxide

Zinc oxide (ZnO) particles were successfully synthesized through the green method using aloe vera extract and zinc nitrate (1:1). The structure, morphology and properties of the biosynthesized ZnO (bioZnO) particles were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), time of flight secondary ion mass spectrometry (TOF-SIMS) and thermogravimetry (TG). The morphology and the size of ZnO particles were elucidated by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). Then, the ability of bioZnO to activate sulfur curing of natural rubber (NR) was tested and compared to commercial ZnO traditionally used as vulcanization activator. The bioZnO showed similar activity in the vulcanization process to commercial ZnO. NR composites containing bioZnO were pro-ecological in nature and exhibited better mechanical characteristics and durability against thermo-oxidative aging than NR with commonly used micrometric ZnO. Moreover, NR vulcanizates containing bioZnO showed good mechanical properties in dynamic conditions and satisfactory thermal stability. The present research is new and in addition to the analysis of biosynthesized ZnO particles, the effect of the activator in the vulcanization process of the NR elastomer and its influence on the properties of the final products were additionally discussed.