Scanning Electron Microscopy-energy Dispersive Spectroscopy Research Articles

Corrosion inhibitive performance of Kopsia teoi extracts towards mild steel in 0.5 M HCl solution

This study investigates the capacity of Kopsia teoi (K. teoi) to inhibit corrosion, employing its stem extracts to prevent mild steel (MS) corrosion in 0.5 M HCl. In this study, three distinct extracts: dichloromethane alkaloid (KTDAE), dichloromethane non-alkaloid (KTDNAE), and methanol (KTME) were employed to investigate their corrosion mitigation performance, involving electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) techniques. EIS results demonstrated a significant increase in inhibition efficiency with concentration for each extract, reaching 87.04, 90.62, and 93.51 % for KTDAE, KTDNAE, and KTME, respectively. According to PD analysis, Kopsia teoi extracts (KTEs) functioned as mixed-type inhibitors. Surface analysis through scanning electron microscopy-energy dispersive X-ray spectroscopy exhibited notable improvements in the morphology of treated MS plates, revealing the establishment of a protective surface film. Langmuir isotherm confirmed that KTEs formed a monolayer on MS surface, and the calculated free energies of adsorption were −25.924, −26.809, and −27.687 kJ mol−1 for KTDAE, KTDNAE, and KTME, respectively. This suggests effective adsorption through both physisorption and chemisorption mechanisms. Consequently, the results of this study highlight the encouraging effectiveness of KTEs as corrosion inhibitors for MS in acidic environments.

Comparative study on the preparation of phosphate-based geopolymers using different activators

Fly ash has the potential to be used as the precursor in the acid-activated geopolymer preparation, fly ash can react with phosphorus-containing activators to form geopolymers, but different types of activators present different activation effects on fly ash. In this study, common liquid phosphoric acid (PA), liquid aluminum dihydrogen phosphate (ADP), solid sodium dihydrogen phosphate (SDP) and solid potassium dihydrogen phosphate (PDP) are used as a single-component or composite activators and fly ash as raw material to prepare phosphate-based geopolymers (PGEOs). The effect of different activators on setting time, pH, electrical conductivity (EC) and compressive strength of PGEOs were assessed. Moreover, the activation mechanism of different activators on fly ash was revealed by using X-ray diffraction, Fourier transform infrared spectroscopy, Mercury Intrusion Porosimetry, X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy-Energy Dispersive Spectroscopy. The results showed that geopolymer prepared using ADP exhibited the highest compressive strength among the different activators, but combining ADP and PA would prolong setting time. However, the unreacted SDP and PDP particles were detected in geopolymers activated by PA+SDP and PA+SDP composite activator due to insufficient geopolymerization. Nonetheless, combining PDP or SDP with PA as composite activator is more effective than the single-component PDP or SDP activator in improving compressive strength. The pH values of the geopolymers increased with the curing time while EC showed a decreasing trend which was independent of the activator type. AlPO4 phase was found in all samples, and Al-containing phases are the main strength-given component of PGEOs.

Surface Modification of Graphene Oxide for Fast Removal of Per- and Polyfluoroalkyl Substances (PFAS) Mixtures from River Water.

Per- and polyfluoroalkyl substances (PFAS) make up a diverse group of industrially derived organic chemicals that are of significant concern due to their detrimental effects on human health and ecosystems. Although other technologies are available for removing PFAS, adsorption remains a viable and effective method. Accordingly, the current study reported a novel type of graphene oxide (GO)-based adsorbent and tested their removal performance toward removing PFAS from water. Among the eight adsorbents tested, GO modified by a cationic surfactant, cetyltrimethylammonium chloride (CTAC), GO-CTAC was found to be the best, showing an almost 100% removal for all 11 PFAS tested. The adsorption kinetics were best described by the pseudo-second-order model, indicating rapid adsorption. The isotherm data were well supported by the Toth model, suggesting that PFAS adsorption onto GO-CTAC involved complex interactions. Detailed characterization using scanning electron microscopy-energy dispersive X-ray spectroscopy, Fourier transform infrared, thermogravimetric analysis, X-ray diffraction, and X-ray photoelectron spectroscopy confirmed the proposed adsorption mechanisms, including electrostatic and hydrophobic interactions. Interestingly, the performance of GO-CTAC was not influenced by the solution pH, ionic strength, or natural organic matter. Furthermore, the removal efficiency of PFAS at almost 100% in river water demonstrated that GO-CTAC could be a suitable adsorbent for capturing PFAS in real surface water.

Advancement in embedding Pb quantum dots into a Porous-Si matrix for superior X-ray radiation detection: An extended gate approach

This study reports on the synthesis of porous silicon (PS) and porous silicon doped with lead (PS–Pb) using an electrochemical method with a primary focus on optimizing key synthesis parameters to enhance material properties. During the synthesis, hydrofluoric acid (HF) and ethanol ratios were maintained at 4:1, which was crucial in achieving the desired structural properties. A structural analysis of the synthesized nanocomposites was conducted using Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (FESEM-EDX). This structural analysis validated the successful incorporation of lead (Pb) into the samples. Among the key aspects of this study were the evaluation of the I–V characteristics of the PS-Pb nanocomposites. Based on the findings of I–V measurements, an increase in the bias voltage was observed, which was directly correlated with an increase in measured current, indicating significant changes in electrical properties as a result of Pb doping. Furthermore, the responses of these materials to X-ray pulse irradiation under various conditions were successfully measured and compared, enhancing the understanding of their potential as radiation detectors. The optimal electrochemical conditions for synthesizing PS and Pd-PS were identified as 90 V, 100 mA, 1 s, and 100 V, 100 mA, 0.5 s, respectively. As a result of optimizing electrochemical synthesis parameters, lead-doped porous silicon (Pb-PS) exhibited a marked reduction in pore size, decreasing from an average of 420.88 nm in undoped PS to 244.54 nm in Pb-PS. This structural refinement correlated with improved electrical properties; I–V measurements demonstrated that the current response at a bias voltage of 0.3 V improved from 1.6×10−5 A to 6.23×10−4 An under identical conditions. Furthermore, these materials responded to X-ray radiation and showed enhanced sensitivity, with Pb-PS detectors achieving a lower response time and higher current under X-ray exposure compared to undoped PS. These findings open up new avenues for employing these nanocomposites in advanced applications, particularly in fields that require precise and efficient radiation detection, such as medical imaging and environmental monitoring. This work represents a significant contribution to the field, illustrating the potential of these custom-engineered materials for the advancement of modern healthcare and detection technologies.

INFLUENCE OF PRECURSOR MOLARITY AND LEAF EXTRACT CONCENTRATION ON PHYSICAL PROPERTIES OF ZINC OXIDE (ZnO) NANOPARTICLES SYNTHESIZED USING MORINGA OLEIFERA LEAF EXTRACT

Zinc oxide nanoparticles (ZnONPs) exhibit optical, electrical, and magnetic properties depending on their size and morphology. These properties are essential for using ZnONPs in various fields such as cosmetics, electronics and medicine. The properties and applications of ZnONPs depend on how they are synthesized, whether physical, chemical, or biological. This study aimed to produce ZnONPs by utilizing the leaf extract of Moringa oleifera and to study the effect of precursor molarity and leaf extract concentration on physical properties. The precipitated compound was characterized using X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), and Scanning Electron Microscopy-Energy Dispersive X-ray spectroscopy (SEM-EDAX). Here, we prepared ZnONPs under four different molarity (0.2[Formula: see text]M, 0.3[Formula: see text]M 0.4[Formula: see text]M, and 0.5[Formula: see text]M) and two different leaf extract concentrations (10[Formula: see text]ml, 15[Formula: see text]ml). We analyzed the difference obtained in the average particle size in each case. From the XRD the major diffraction peaks are observed at 36.3, 47.53, 36.33, and 36 for 0.2[Formula: see text]M, 0.3[Formula: see text]M, 0.4[Formula: see text]M, and 0.5[Formula: see text]M, respectively. The average particle size was found to be in the range of 12–30[Formula: see text]nm. UV study was used to inspect the optical nature of the prepared ZnONPs and SEM confirmed the sample’s morphology. Investigations on the role of precursor molarity and leaf extract concentration in synthesizing ZnONPs indicated that average particle size increases with increasing precursor molarity and leaf extract concentration. The study also suggested that synthesizing metal oxide nanoparticles using botanical extract is an eco-friendly alternative to physical and chemical methods.

Simple distance-based thread analytical device integrated with ion imprinted polymer for Zn2+ quantification in human urine samples.

This article presents the development of a distance-based thread analytical device (dTAD) integrated with an ion-imprinted polymer (IIP) for quantitative monitoring of zinc ions (Zn2+) in human urine samples. The IIP was easily chemically modified onto the thread channel using dithizone (DTZ) as a ligand to bind to Zn2+ with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as well as 2,2-azobisisobutyronitrile (AIBN) as cross-linking agents to enhance the selectivity for Zn2+ detection. The imprinted polymer was characterized using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Under optimization, the linear detection range was from 1.0 to 20.0 mg L-1 (R2 = 0.9992) with a limit of detection (LOD) of 1.0 mg L-1. Other potentially interfering metal ions and molecules did not interfere with this approach, leading to high selectivity. Furthermore, our technique exhibits a remarkable recovery ranging from 100.48% to 103.16%, with the highest relative standard deviation (% RSD) of 5.44% for monitoring Zn2+ in human control urine samples, indicating high accuracy and precision. Similarly, there is no significant statistical difference between the results obtained using our method and standards on zinc supplement sample labels. The proposed method offers several advantages in detecting trace Zn2+ for point-of-care (POC) medical diagnostics and environmental sample analysis, such as ease of use, instrument-free readout, and cost efficiency. Overall, our developed dTAD-based IIP method holds potential for simple, affordable, and rapid detection of Zn2+ levels and can be applied to other metal ions' analysis.

Performance of solid-oxide fuel cells operating with different sustainable fuel reformates

Solid oxide fuel cells (SOFCs) are recognized for their outstanding fuel flexibility and high efficiency in converting chemical energy into electrical energy. This research presents experiments on SOFCs fed with humidified hydrogen and hydrogen-rich gaseous reformates derived from methanol and ammonia: methanol steam reforming (MSR), methanol decomposition (MD), and ammonia decomposition (AD), at 700–850 °C. Results of SOFCs operating with MD reformate on different types of SOFCs, which to the best of our knowledge aren't available in the literature, are presented and compared with other reformate types for the first time. MD-reformate yielded the highest cell performance, with the least disparity in power density from humidified hydrogen, followed by AD-, and MSR-reformates. The study compares the direct internal reforming method, and the innovative Combined Electro-Thermo-Chemical cycle's potential. Introducing the concept of critical power density, the research evaluates fuel utilization across SOFC types. Scanning Electron Microscopy imaging and Energy-Dispersive X-ray Spectroscopy analyses confirm the viability of CO as a fuel, with no carbon deposits on the anodes when using MD-reformate. The findings demonstrate the suitability of using methanol- and ammonia-decomposition products in SOFCs and their compatibility with hybrid power generation cycles.

Imaging porosity evolution of tight sandstone during spontaneous water imbibition by X-ray Micro-CT

Water imbibition is an important process in reservoir rocks during hydraulic fracturing and water-based enhanced oil recovery operations. However, the water imbibition behavior in tight sandstones has not been fully understood due to their complex pore structure, including the presence of nano and micron-sized pores and throats, surface properties, and wide variation in mineralogy. The present study focuses on the effect of spontaneous water imbibition on the porosity evolution of a tight sandstone. Within this context, a core of Torrey Buff sandstone was characterized by using a combination of multiscale imaging methods (X-ray Computed Tomography, Scanning Electron Microscopy), laboratory experiments (porosity-permeability measurements), and analytical techniques (X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy-Energy Dispersive Spectroscopy, and Thermogravimetry). The studied tight sandstone core has a porosity of 12.3 % and permeability of 2.05mD with minerals of quartz (58 %), clays (kaolinite and illite, 23 %), K-feldspar (7 %), dolomite (7 %) and calcite (5 %). Primary and secondary pores, ranging in size from 60 to 140 μm and 30–50 μm, respectively, are mostly filled with highly-soluble carbonate minerals and hydrophilic illite, which influence the spontaneous water imbibition capacity of the tight sandstone. The multiscale imaging technique indicates that after a 10-h long water imbibition experiment, the average pore size of the tight sandstone increased by 1.28 %, reaching 2.35 % at the rock-water contact and 0.13 % at the top of the core. In other words, throughout the core, the porosity changes upon water imbibition are not uniform but show an almost linear trend. This observation could be explained by the significant contribution of highly-soluble carbonates and hydrophilic illite on the microstructure of the tight sandstone. This study implies that multiscale imaging techniques, crucial in examining spontaneous water imbibition, hold promise for further research in enhanced oil recovery or hydraulic fracking in tight sandstones.

Characterization of Microplastic Degrading Indigenous Bacteria from Ambon Bay Waters

Microplastic degradation by bacteria can degrade low-density polyethylene (LDPE). This study aimed to analyze the potential of Ambon Bay bacteria for microplastic degradation, the condition of microplastics after degradation, and identification of the potential for microplastic degradation. The results of isolation revealed as many as 20 bacterial isolates, which correlated with physicochemical conditions in the waters of Ambon Bay. Nine of them could degrade microplastics as indicated by the presence of a clear zone, namely KA1, KA2, KA3, KA4, KA5, KA9, KA10, KS6, and KS8. They were checked for biofilm formation, microplastic hydrophobicity, and percentage of microplastic weight reduction. Four isolates with the highest percentage of microplastic weight reduction on day 40 were KA1, KA2, KA3, and KA10 at 36.19%, 10.16%, 28.39%, and 17.07%, respectively. The results of LDPE microplastic degradation showed differences using field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM/EDS), attenuated total reflection-fourier transform infrared (ATR-FTIR), and X-ray diffraction (XRD). The bacterial isolates identified were KA1 (Bacillus cereus), KA2 (Bacillus toyonesis), KA3 (Bacillus paramycoides), and KA10 (Escherichia coli). Indigenous bacteria from the waters of Ambon Bay have the potential to degrade LDPE microplastics, which causes structural changes, decreased crystallinity, weight, and C=C groups in microplastics after degradation, with bacterial isolate KA1 identified as Bacillus cereus showing the best potential with degradation of LDPE microplastics by 36.19%.

Characterization of bone and dung biochars for potential use as precursors for artificial fertilizers

The Fourier Transform Infrared technique was utilized to measure the infrared spectra of bone and dung chars at ambient temperature. The spectra of the investigated char samples showed some notable similarities, suggesting that the compounds have functional groups which display bands at similar wavenumbers in IR spectrum. Additionally, correlations between the chars and the terra preta soils were found. This implies that the investigated biochars and the terra preta soils share comparable characteristics. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy showed the existence of calcium, phosphorus, magnesium and oxygen in the bone char which are classified as macronutrients. In addition, the bone char contained two micronutrients (nickel and chlorine) and one non-essential nutrient (sodium). The dung char was constituted with all the macronutrients found in the bone char and in addition it had traces of sulfur which is also a macronutrient. Iron, manganese and chlorine were present in the dung char as micronutrients. There was also the presence of sodium and aluminum which are classified as non-essential nutrients. Zinc which is also fundamental in soil fertility was detected using Atomic Adsorption Spectroscopy in all the chars. Both the samples are alkaline with pHs ranging between 9 and 11. The results of this research will be useful in determining which biochars are best suited for production of synthetic fertilizers.

Investigation of the influence of different types of electrolytes on the performance of the Electrochemical Discharge Machining process during micromachining of molybdenum

Electrochemical Discharge Machining (ECDM) is a hybrid process that integrates the principles of Electrochemical Machining (ECM) and Electrical Discharge Machining (EDM) to create micro-holes in both conductive and non-conductive materials that are typically difficult to machine. Given the unpredictable nature of this hybrid method, the composition of the electrolyte emerges as a critical factor influencing the accuracy and performance of the machining process. Consequently, the optimization and analysis of electrolytes are pivotal for the efficient utilization of energy during ECDM and for ensuring machining precision. This study aims to experimentally investigate the impact of various types of electrolytes and their concentrations. These are divided into two categories: neutral solutions, which include sodium nitrate (NaNO₃) and sodium chloride (NaCl), and alkaline solutions, comprising sodium hydroxide (NaOH) and potassium hydroxide (KOH), as well as a mixture of both NaOH and KOH. The evaluation metrics considered include the Material Removal Rate (MRR), Tool Wear Rate (TWR), overcut (OC), Heat Affected Zone (HAZ) and surface quality. It was observed that alkaline solutions, particularly the mixed electrolyte, resulted in higher MRR and HAZ, reduced TWR, and the production of micro-holes with minimized overcut compared to using KOH and NaOH separately or neutral solutions, while also enhancing surface quality. Further analysis using Scanning Electron Microscopy (SEM) images and Energy-Dispersive Spectroscopy (EDS) of the brass tools used with different electrolytes revealed that tools used in KOH and mixed electrolytes exhibited less wear and material erosion compared to those used in NaOH and neutral solutions.

High-Temperature Cyclic Oxidation Behavior and Microstructure Evolution of W- and Ce-Containing 18Cr-Mo Type Ferritic Stainless Steel.

Due to the recurrent starting and stopping operations of automobiles during service, their engines' hot ends are continually subjected to high-temperature cyclic oxidation. Therefore, it is crucial to develop ferritic stainless steels with better high-temperature oxidation resistance. This study focuses on improving the high-temperature cyclic oxidation performance of 18Cr-Mo (444-type) ferritic stainless steel by alloying with high-melting-point metal W and the rare earth element Ce. For this purpose, a high-temperature cyclic oxidation experiment was designed to simulate the actual service environment and investigate the high-temperature cyclic oxidation behavior and microstructure evolution of 444-type ferritic stainless steel alloyed with W and Ce. The oxide structure and composition formed during this process were analyzed and characterized using scanning electron microscopy/energy dispersive spectroscopy (SEM-EDS) and electron probe X-ray micro-analyzer (EPMA), in order to reveal the mechanism of action of W and Ce in the cyclic oxidation process. The results show that 18Cr-Mo ferritic stainless steel alloyed with W and Ce exhibits an excellent resistance to high-temperature cyclic oxidation. The element W can promote the precipitation of the Laves phase between the matrix and the oxide film, and the small-sized Laves phase can inhibit the interfacial diffusion of oxidation reaction elements and prevent the inward growth of the oxide film. The element Ce can refine oxide particles and reduce the thickness of the oxide film. CeO2 particles within the oxide film can serve as nucleation sites for the formation of oxide particles from reactive elements, and they also contribute to pinning the oxide film, thereby enhancing its adhesion.

Direct carbonation of porous materials produced from self-hardened paper mill fly ash

A high-Ca fly ash generated from a paper mill using a fluidized bed boiler was used as the potential medium to sequester CO2 via the direct carbonation process. In this study, the fly ash samples were exposed to accelerated carbonation to produce hardened pastes. The influence of the porosity controlled by the amount of foam in the matrix for maximizing CO2 sequestration was determined. The effect of porosity on carbonation was evident. The samples prepared with 40 % foam and a water-to-fly ash ratio of 0.79 recorded porosities of 56.1 % (carbonated) and 66.8 % (naturally carbonated (NC)) with the lowest mechanical strength of 2.1 and 1.1 MPa, respectively. These naturally carbonated (NC) samples have been cured naturally without using high CO2 pressure. Meanwhile, the samples prepared with 10 % foam and a water-to-fly ash ratio of 0.5 recorded porosities of 41.1 % (carbonated) and 52.9 % (NC) with the highest strength at 10.2 and 4.6 MPa, respectively. The highest carbonation efficiency determined by thermogravimetric analysis was obtained from the carbonated samples with 40 % foam. Scanning electron microscopy–energy-dispersive spectroscopy depicted the areas with high Al/Si content but low Ca–O content (dark areas) and carbonated areas with high Ca–O content (bright areas). Mercury intrusion porosimetry was used to determine the pore size distribution, whereby the samples were dominated by large capillary pores, resulting in their high porosity in this study.

In-Situ Synthesis of CuO/TiO2 Nanocomposite Onto Amine Modified Cotton Fabric for Antibacterial Durability and UV Protection

ABSTRACT In this research work, we explore antibacterial activity and the UV-protection of cotton fabric functionalized with copper oxide-titanium dioxide nano composites particles (CuO+TiO2 NCPs). Cotton fabrics (Cot) were treated with L-methionine (Am) and functionalized with bimetallic CuO+TiO2 NCPs by pad and rolling technique. Cu(NO3)2 and titanium isopropoxide (TIP) were used as sources of Cu(OH)2 and TiO2 colloid respectively, which were then converted into CuO and TiO2 nanoparticles (NPs) for making antibacterial and UV-protective cotton. The method yielded a crystallite size of CuO and TiO2 NPs of 18.09 and 32.5 nm, respectively. FTIR, Raman spectroscopy, High-resolution scanning electron microscopy-Energy dispersive Spectroscopy (HRSEM), (EDS), X-ray photo spectroscopy (XPS), thermal gravimetric analysis (TGA), and XRD were used to analyze the functional group, morphology, chemical composition, thermal stability and crystalline structure of the functionalized cotton fabric samples. The results showed that an esterification reaction occurred between Am and OH in cotton fabric, which further enhanced the binding of NCPs. AmCot-CuO+TiO2 NCPs exhibit outstanding antibacterial activity against gram-positive S. aureus and gram-negative E. coli. The UV protection factor (UPF) for AmCot-CuO+TiO2 NCPs reached 50+; thus, multifunctional cotton fabrics with excellent antibacterial and anti-ultraviolet properties were obtained.

Preparation, characterization and photocatalytic studies of defect pyrochlore, KMn0·33Te1·67O6 and its composite with g-C3N4

Skeletal materials belonging to the defect pyrochlore family have been the subject of considerable interest due to their remarkable properties. In this work, a highly efficient, stable and visible light active composite photocatalytic system consisting of defect pyrochlore of composition KMn0·33Te1·67O6 (KMnTeO) and g-C3N4 (g-CN) has been successfully prepared by simple physical mixing of pre-prepared KMnTeO and g-CN components synthesized in solid state and thermal treatment of low-cost melamine, respectively. Structural, morphological and optical properties of as-prepared catalysts were deduced from powder X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR), Raman, Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (FESEM-EDX), Transmission Electron Microscopy-High Resolution Transmission Electron Microscopy (TEM-HRTEM), Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–Vis DRS), X-ray Photoelectron Spectroscopy (XPS) and Photoluminescence (PL) measurements. The lattice parameter “a” of parent KMnTeO was obtained from Rietveld refinement of its powder XRD pattern. The FT-IR and Raman spectra of KMnTeO gave characteristic bands belonging to the defect pyrochlore structure. The photocatalytic activities of KMnTeO and composite KMnTeO-g-CN were evaluated by the degradation of methylene blue (MB). Scavenger experiments were carried out to identify the reactive species responsible for the degradation of MB. Furthermore, the reusability and stability of the photocatalysts were explored. The probable photocatalytic mechanism for MB degradation over the composite KMnTeO-g-CN was surmised according to the scavenger experiments. The work provides a new approach for the development of novel defect pyrochlore based composite photocatalysts to treat industrial wastewater containing organic pollutants.

Catalytic upgrading of Naomaohu coal pyrolysis volatiles over NiAl and NiLiAl oxides

Catalytic upgrading of volatiles is an essential technology to improve the product distribution of pyrolysis for the clean and efficient utilization of low-rank coals. In this work, novel acid-base bifunctional catalysts composed of Ni/Li/Al oxides were designed and prepared using LDH precursors with tunable chemical composition and structural properties. The catalysts were systematically characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), physisorption, NH3-temperature programmed desorption (NH3-TPD), CO2-temperature programmed desorption (CO2-TPD), H2-temperature programmed reduction (H2-TPR), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). A two-stage fixed bed reactor was employed to evaluate the performance of the catalysts. Characterization results suggest that the crystal size of NiO and the surface area of the catalyst decreased with increasing Li content and decreasing Ni content in the catalyst, while the pore volume and pore diameter were positively correlated with Li content. Moreover, the addition of Li reduced the amount of weak acid sites and raised the amount of total basic sites. Consequently, the bifunctional catalysts boosted the yield of light tar and the contents of aromatics and phenols in tar. Specifically, with the highest total acid sites (569 μmol/g) promoting the cracking of heavy pitch components, Ni2.5Li0.5Al1 decreased the content of pitch in tar to 23.8 wt%, representing a 42.7 % drop from the corresponding non-catalytic pyrolysis. Accordingly, it improved the light tar yield to 7.2 wt%, which was 18 % higher than non-catalytic pyrolysis. 450 °C is identified as a suitable temperature for the catalytic upgrading of volatiles from Naomaohu coal; higher catalysis temperatures at 500 °C and 550 °C led to lower tar yield and lower phenols content, along with higher gas yield and more carbon deposition.

Development and Characterization of a Remanufactured Motorcycle Clutch Hub from End-of-Life Aluminium Alloy

This study aims to employ reverse engineering in the development of the Yamaha CY 80 motorcycle clutch hub using end-of-life (EOL) aluminium alloy obtained from automotive vehicle scraps. The remanufactured motorcycle clutch hub underwent characterization and transient thermal analysis by integrating the geometric and structural features of the clutch hub. The EOL aluminium was thoroughly washed with a sodium hydroxide (NaOH) solution, cleaned with running water, and dried under sunlight to remove impurities trapped on the metal surfaces. The EOL aluminium alloy was melted in a gas furnace, and the molten metal was cast into the clutch hub using a permanent mold designed with the geometric features and characteristics of the Yamaha CY 80 motorcycle clutch hub. The EOL aluminium alloy was characterized using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The remanufactured CAD model of the Yamaha CY 80 motorcycle clutch hub was subjected to transient thermal analysis using ANSYS Workbench to predict the thermal behavior of the clutch hub during operation. The FTIR spectra exhibited the following distinctive bands: Al-O stretching modes in octahedral and tetrahedral structures, as well as symmetric bending of Al-O-H, with wavenumbers between 340 and 3131 cm-1 for -OH bonds and between 2109 and 1688 cm-1 for H-O-H bonds. The SEM-EDS micrographs indicated that the two main elements were bromine and silicon. Results from the transient thermal analysis indicated that the minimum and maximum temperatures were 40.109 °C and 250.09 °C within a time frame of 240 seconds. The maximum total heat flux was 30,271,000 W/m2. The compressive yield strength and tensile yield strength obtained in this study were 280 MPa, while the ultimate tensile strength was measured at 310 MPa. The alternating stress levels ranged from 62.05 MPa to 275.8 MPa. This study established that the material is susceptible to fatigue failure, as the alternating stress levels were below the material’s yield strength of 280 MPa.

Effect of ZrO2 on the phase relations for CaO-SiO2-TiO2 system related to efficient extraction of titanium from titania-bearing slag

The selective crystallization and phase separation process has been regarded as a promising process for the recycling of titanium from titania-bearing furnace slag, however, the composition modification mechanism still remains unclear due to the lack of fundamental thermodynamic data. In the present work, the influence of ZrO2 addition on the equilibrium phase relations and the 1400 °C isotherm for CaO-SiO2-TiO2 system were experimentally determined by using the high temperature equilibration-quenching technique, and Scanning Electron Microscopy-Energy Dispersive X-ray Spectrometry, and X-ray diffraction analysis. The equilibrium solid phases of rutile (TiO2), perovskite (CaTiO3), and tridymite (SiO2) are determined to be coexisting with the liquid phase. In addition, comparisons of present results with thermodynamic calculation by FactSage show significant discrepancies. The present work is important for enriching the thermodynamic database of titania-bearing slag oxide systems as well as optimizing the selective crystallization and phase separation process.

High entropy (HfTiZrVNb)B2 ceramic particulate reinforced Al matrix composites: Synthesis, mechanical, microstructural and thermal characterization

This study aims to introduce a novel type of particulate reinforced Al matrix composite. High entropy (HfTiZrVNb)B2 ceramic particulate reinforced Al matrix composites were produced via a combined process of different powder metallurgy methods. Firstly, boride compounds (HfB2, TiB2, ZrB2, VB2, NbB2) were synthesized in the laboratory scale using the related metal oxide, boron oxide, and magnesium by mechanochemical synthesis (MCS) and leaching processes under optimum conditions. Secondly, the synthesized and purified boride powders were mixed in equimolar ratios using a planetary ball mill for 72 h, and they were sintered at 2000 °C under 30 MPa via spark plasma sintering (SPS). Thirdly, equimolar high entropy (HfTiZrVNb)B2 bulks were crushed, converted into powder forms, and added into Al powders at different amounts as 1, 2, 5, 10, and 15 wt %. Lastly, these powder blends were mechanically alloyed in a vibratory ball mill for 6 h, cold pressed and pressureless sintered at 630 °C for 2 h. For characterization techniques, X-ray diffractometry (XRD), thermal analysis, scanning electron microscopy/energy dispersive spectrometry (SEM/EDS), density measurements using pycnometer and Archimedes' methods, microhardness and dry sliding wear tests were conducted on the sintered composites. The highest hardness (∼1.5 GPa) and the lowest wear rate (∼0.0012 mm3/Nm) were obtained in the Al-15 wt % (HfTiZrVNb)B2 sample.

Mining Metal‐Biomolecular Framework/PANI Composite CO Sensor: Material Synthesis, Gas Sensing Performance and Mechanism

AbstractIn addressing the issue of poor gas sensitivity in semiconductor CO sensor materials used in mining, such as pure PANI. This study utilized an ice‐water bath in combination with an in‐situ polymerization method to synthesize a new composite material consisting of Cu(II)‐racemic glutamate nanofibers and PANI. The morphology, structure, and chemical bonds of the composite material were analyzed using scanning electron microscopy‐energy dispersive spectroscopy (SEM‐EDS) and spectral analysis. The material's ability to detect CO (100–500 ppm) at room temperature was investigated, revealing a response value of up to 6.8 % for 400 ppm CO detection when the composite material was deposited on a ceramic interdigital electrode. The material exhibited good selectivity and responsiveness to CO detection at room temperature, attributed to the heterojunction formed between Cu(II)‐racemic glutamate nanofibers and PANI, which enhanced carrier migration. Consequently, the Cu(II)‐racemic glutamate nanofiber/PANI composite(Cu(II)‐RGlu/PANI) material shows promise as a high‐performance sensing material for CO detection at room temperature and as a low‐power, integrable sensor material for underground coal mines. This research contributes to the development of a theoretical framework for such applications.