X-ray Diffraction Results Research Articles

Optical Study on Temperature-Dependent Absorption Edge of γ-InSe-Layered Semiconductor

We have studied the variations in the temperature-dependent absorption edge of a bulk InSe-layered semiconductor using photoconductivity (PC) measurements. From both the X-ray diffraction (XRD) and Raman experimental results, the structural phase of the as-prepared InSe sample was confirmed to be γ-polytype. Upon heating from 15 K to 300 K, the absorption edge of PC spectra was found to shift significantly toward lower energy, and the absorption edge as a function of temperature was further analyzed by the Varshni’s relationship and Bose–Einstein empirical equation. The Urbach energy as a function of temperature was obtained by fitting the absorption tail below the absorption coefficient of the PC spectrum, and the effective phonon energy can be derived from the temperature-dependent steepness parameter associated with Urbach energy. Our study indicates that the broadening of the absorption edge in the as-synthesized bulk γ-InSe is caused by a combination of electron/exciton–phonon interactions and thermal/structural disorder.

Synergistical improvement in toughness and strength of multi-doped W-Hf-Y2O3 alloy via formation of complex oxide particles

As the primary candidate material for plasma facing components (PFCs) in fusion reactor, the serious brittleness of tungsten has become an urgent issue to be solved. In this work, a multi-doped W-Hf-Y2O3 alloy was prepared by high-energy ball milling and spark plasma sintering, aiming at improving its toughness through formation of complex oxide particles. Complex Y2Hf2O7 with pyrochlore structure were developed in the multi-doped WHY alloy due to dissolution and precipitation mechanism, which was confirmed by the combined characterization results of X-ray diffraction (XRD), electron probe microanalysis (EPMA) and transmission electron microscope (TEM). Complex oxide particles of Y2Hf2O7 with average size of 38.8 nm were densely distributed in the alloy. The formation of complex Y2Hf2O7 particles with nano-scale size not only consumed the impurity of oxygen, but also played a critical role in grain refinement because of Zener pinning effect. Improvement in mechanical properties of the multi-doped WHY alloy was then achieved, and the fracture toughness and compressive strength reached 19.7 MPa·m1/2 and 2223.4 MPa, respectively.

Composite energy storage cement-based mortar including coal gasification slag/paraffin shape-stabilized phase change material: physical, mechanical, thermal properties

Using renewable sources to generate energy is an approach to realize a sustainable energy system. Utilizing gasification slag, a solid waste from the coal gasification process, as a porous material not only substantially increases the value of the waste but also enhances thermal performance. This study develops a novel shape-stabilized coal gasification slag/paraffin (CGS-P) phase-change material for use in cement mortar to reduce indoor temperature fluctuations. Using a simple impregnation method, paraffin is incorporated into porous coal gasification slag to produce CGS-P. Coal gasification slag containing 30 % paraffin (CGS-P(30 %)) can maintain its structure without leakage at 60 °C. The thermal and chemical characteristics as well as the specific surface area of CGS-P(30 %) are characterized via X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, Brunauer–Emmett–Teller (BET) analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM)–energy-dispersive X-ray spectroscopy. The results of XRD and FT-IR analyses indicate that CGS-P(30 %) is a combination of paraffin and CGS, with no new substances formed. Furthermore, the BET, SEM, and TGA results confirm that the pores in CGS can effectively encapsulate approximately 30 % paraffin and that CGS-P(30 %) exhibits good thermal stability. The DSC analysis results show that CGS-P(30 %) has suitable phase-change temperatures and latent heat (18.02 °C and 59.30 J/g, respectively, during the endothermic phase). Furthermore, incorporating 30 % CGS-P(30 %) into the cement mortar (CESCM30) results in good mechanical and thermal performance. Particularly in hot climates, CESCM30 can notably reduce indoor temperatures, alleviate indoor cooling energy consumption, and indirectly reduce CO2 emissions. Therefore, CGS derived CGS-P is a promising material for accommodating solar thermal energy.

Assessing the Effect of Fe2O3 Nanoparticles on Catalase Activity in Patients with Chronic Periodontitis: In Vitro study and Molecular Docking

Periodontal disease, also known as gum disease, is a chronic inflammatory condition that affects the supporting structures of the teeth, including the gums and underlying bone. It is primarily caused by a bacterial infection resulting from poor oral hygiene practices. The main objectives of the current study were to synthesize iron oxide nanoparticles (Fe2O3-NPs) and their characteristics were analyzed through UV, SEM, and X-ray analysis. Additionally, the dispersion of the synthesized NPs was investigated using UV and TEM techniques. The study also aimed to assess the kinetic behavior and the impact of Fe2O3-NPs on catalase activity in the saliva of the patient and control groups. The findings revealed a significant increase in catalase activity (p>0.05) in both serum and saliva of all patient groups compared to the control group. The UV-visible spectrum shows that the absorption peaks for synthesized α- and γ-iron oxide nanoparticles was at 225 nm. According to the SEM image analysis, the primary particle size of the nano-particles is approximately 26.8 nm. The X-ray diffraction results indicate that the Fe2O3-NPs range in size from 14 nm to 26 nm. UV and TEM study conclude that water a suitable solvent for Fe2O3-NPs dispersion on kinetic study of catalase (CAT) activity. The kinetic data cleared that the α-Fe2O3-NPs have an inhibitory effect for the total activity of salivary CAT in the samples of both healthy and patients with chronic periodontitis. Lineweaver–Burk graph showed that (α-Fe2O3) inhibit catalase by un comp. inhibition. γ-Fe2O3-NPs inhibited total salivary CAT activity in healthy and patients with chronic periodontitis samples. Lineweaver –Burk graph showed that (γ-Fe2O3) inhibit catalase by uncompetitive inhibition.

Exogenous application of salicylic acid and putrescine triggers physiological and biochemical changes in plants to improve growth and bioactive constituents of Ammi majus L

Ammi majus L. is a rich source of coumarins in addition to various flavonoids, alkaloids, and terpenoids. Medicinal products of Ammi majus seed, with sunlight exposure, are worldwide used for the treatment of vitiligo (pale-white patches on the skin). To increase the content of seed-coumarins and to investigate the physiological reasons in this respect, two net-house experiments were conducted using foliar-spray treatments (0, 25, 50, 100 and 200 mg L−1) of salicylic acid (SA) (Experiment 1) and putrescine (PUT) (Experiment 2). All studied parameters were improved due to the foliar application of both growth elicitors (SA and PUT). The best outcomes for SA and PUT were obtained at 50 mg L−1 which maximally increased the growth characteristics, physiological and biochemical attributes, and seed quality parameters. In comparison to the control, 50 mg L−1 of SA and PUT increased the chlorophyll content by 26.3% and 25.5%, carotenoid content by 31.4% and 18.5%. In addition 50 mg L−1 of both SA and PUT gives the best results of FTIR (Fourier Transform Infrared Spectrophotometer) & XRD (X-ray Diffraction) analysis. In GC–MS analysis, 50 mg L−1 of SA and PUT increases the Methoxsalen content (17.44 and 16.81%) and 7H-Furo[3,2-g]. Bown (1995) [1] Benzopyran-7-one, 4,9-dimethoxy content(14.92 and 13.93%) and p-camphorene content (13.11 and 12.27%) in contrast to the control. Other important constituents were Pimpinellin (6.31 and 4.08%), Bergapten (8.72 and 6.220, Isospathulenol (7.80 and 2.47), Octadecenoic acid (5.78 and 3.59) and Vitamin E (1.48 and 0.16).

Investigation of the role of sintering temperature on microstructure, ac conductivity, and dielectric constant of single phase NiSnO3 nanopowder

This study investigates the effect of sintering temperature on the structural and electrical properties of co-precipitated nickel stannate (NiSnO3) nanopowder. Sintering temperatures, determined using Thermo Gravimetric Analysis (TGA), reveal a pure hexagonal perovskite structure through X-ray diffraction (XRD) analysis. Crystallite size increased from 10.56 nm to 26.04 nm and lattice strain decreased from 23.05×10−3 to 2.35×10−3 with higher sintering temperatures, analyzed via the Scherrer formula. d-spacing values from SAED patterns align with XRD results, and TEM analysis shows particle size growth from ∼11.43 nm to ∼28.16 nm as sintering temperature rises from 600°C to 900°C. Elemental composition has been confirmed through EDX, and elemental mapping analysis. Impedance spectroscopy via Cole-Cole plots indicated non-Debye-type or multiple relaxations with depressed semicircles due to grain and grain boundary effects. The sample sintered at 900°C exhibits the highest conductivity (8.35×10−5 Ω−1cm−1) with lowest activation energy of 0.31 eV and maximum dielectric constant values, with a minimum relaxation time of 0.00029 sec. Also the frequency variation of Z′′ and M′′ confirm the presence of non-Debye type relaxation. Scaling behavior of the imaginary part of complex impedance and conductivity spectra confirms temperature-independent conduction and relaxation mechanisms. These materials are used in energy storage applications.

Osmotic absorption behaviors of imidazolium ILs in digestive system and their effective removal way

Considering the controversial safety and risk solutions of ionic liquids (ILs), more essential basic researches are required as their applied fields become broader and applied scale grows larger. Under this background, the permeation behaviors of six common imidazole ILs on porcine gastric and enteric membranes together with the feasibility of their removal by adsorption with montmorillonite were investigated in vitro. Through the single-factor investigation of different cations, anions and ionic liquid concentrations, the current results show that the IL of 1-ethyl-3-methylimidazolium bromide ([Emim]Br) has the strongest permeation capacity on the gastric membrane during the tests. The cumulative permeation amount of Qn can reach 0.72 mg/cm2, and the cumulative permeation percentage alsoreaches 95.77 %; the whole permeation process conforms to the Hixcon-Crowell model. As comparison, the maximum cumulative penetration percentage of [Emim]Br on enteric member was determined as 89.11 %, and related models was also compared. In order to remove the potential IL in digestive tract, montmorillonite was screened out from those popularily used antidotes in clinic and the adsorption of [Emim]Br in gastric fluid by montmorillonite has been proved more consistent with the second-order kinetics and Langmuir model. The results of molecular simulation, infrared spectrum (IR), X-ray diffraction (XRD) and thermogravimetric (TG) characterization exhibit that [Emim]Br has been successfully adsorbed into the interlayer of montmorillonite. As a whole, the study provided a scientific and effective way to diminish the hidden danger of ionic liquid entering the blood through the digestive system.

Cytotoxic potential of Curcuma caesia rhizome extract and derived gold nanoparticles in targeting breast cancer cell lines

Among all types of cancer, breast cancer is the most aggressive, as it is responsible for most of the cancer related death of women. Though several medical therapies are available, the scenario of curing such disease is not favorable. Therefore, there is an urgent need to find alternatives to deal with it. The knowledge of ethnopharmacy might give some better solution to mitigate such deadly diseases. Here, we are using the rhizome of Curcuma caesia Roxb. (Black turmeric), as well as gold nanoparticles (GNPs) synthesized with it to check their specific cytotoxic potentiality against breast cancer cell lines. In our study, ethanolic extract was used to evaluate the cytotoxic effect of the rhizome. GNPs were synthesized by using the same extract and characterized by UV–Vis spectroscopy (UV–Vis), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Thermo gravimetric analysis (TGA). The TEM, XRD, FTIR and TGA results revealed the successful synthesis and capping of GNPs. The UV–Vis Spectrum showed a sharp and narrow absorption peak at 550 nm and HRTEM confirmed both the stability and successful synthesis of the nanoparticles. The MTT assay of the crude extract revealed strong cytotoxicity against breast cancer cell lines viz. MCF-7 (ER+) and MDA MB-231 (Triple Negative Breast Cancer, TNBC) by showing IC50 values as 15.70 ± 0.029 and 21.57 ± 0.031 μg/mL respectively. For extract mediated GNPs, the IC50 values were found to be 6.44 ± 0.045 and 5.87 ± 0.031μg/mL respectively in both breast cancer cell lines. As the IC50 value for GNPs was found to be much lower than that of crude extract, it indicates a higher efficiency of the GNP. However, both the rhizome extract and its mediated GNPs showed more toxicity towards MDA MB-231 (TNBC) cell lines. It was also observed that the GNPs showed more toxicity towards TNBC cell lines compared to the rhizome extract. No toxicity was found in case of other cell lines such as L 929 and HeLa for both crude extract as well as for GNPs. These observations suggests that both the crude rhizome extract and its derived GNPs exhibit selective cytotoxic potential against breast cancer cell lines, which might be exploited for target specific treatment. Moreover, with an understanding of the mechanism behind the GNPs therapeutic efficiency, it can be developed as a personalized therapy to treat such type of cancers.

Experimental investigation on Nano-Al2O3 and hydroxypropyl methyl cellulose (HPMC) modified cement-based coatings for corrosion resistance

In this work, cementitious coatings doped with nano-Al2O3 (NA) and hydroxypropyl methyl cellulose (HPMC) were prepared in order to enhance corrosion resistance of steel bar. The electro-chemical behaviors and corrosion inhibition properties of coated steel bar and tensioned coated steel bars (subjected to 10 %, 30 % and 50 % yield load) were analyzed in 3.5 wt% NaCl solution for 840 h (35 days). At the end of electrochemical test, coating overall performance was evaluated by visual inspection. In addition, scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS) were used to examine microstructure and elemental composition of coatings. To comprehend the anti-corrosion mechanism of the coatings, X-ray diffraction (XRD) and infrared spectroscopy (FTIR) analysis to characterize products composition and chemical groups. Test results obtained by linear polarization resistance and electrochemical impedance spectroscopy indicated that both tensile and non-tensile coatings resistance show an increasing trend followed by a decrease with increasing NA content. Cementitious coatings incorporating 1 % NA and 0.12 % HPMC by weight of cement exhibited the best corrosion protection. The LPR fluctuates around 3700 Ω cm2, which is about twice as much as a single doped NA coating. Whether subjected to tensile loads or not, OCP values for all coated steel bar were below −0.273 V/SCE, indicating has a 90 % probability of being in active-corrosion. The corrosion resistance of tensioned coated bars decreased as time and increased load level. According to SEM and TEM image, HPMC forms a thin and continuous film on the substrate surface, which acts as a barrier to the penetration of moisture and corrosive agents. Coatings doped with 1 % NA and 0.12 % HPMC formed denser integrated polymer films at the microscopic. FTIR and XRD results showed that coating incorporated NA consumed the cement hydration product Ca(OH)2 to generate more nanofibers filling pores and microcracks. Coatings incorporating HPMC show better resistance to carbonization.

Design and construction of bio carbon derived Bi2Fe4O9 nanocomposites sensor for clad modified optical fiber sensors for detection of ethanol gas

Bio carbon (BC) derived Bi2Fe4O9 hybrid sensor was fabricated via sonochemical approach. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and N2 adsorption-desorption were used to determine the structural, morphological and porosity characteristics, respectively. The materials' gas-sensing properties were evaluated using a clad-modified optical fiber sensor. The orthorhombic structure with Pbam space group of Bi2Fe4O9 confirmed by the relative diffraction pattern. All sharp intense diffracted patterns might be indexed based on the standard value ((JCPDS card No. 74-1098). Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images illustrate those granular sheets with aggregated spherical shaped morphology of BC and Bi2Fe4O9, respectively. The pristine Bi2Fe4O9 exhibits Raman modes at 378 cm−1 and 617 cm−1, which is ascribed to the orthorhombic structure. The orthorhombic structure was already confirmed from XRD results. BFOG5 sample shows high SSA (107.5 m2/g) and pore size (38.4 nm), which is nearly 2.2 times greater than that of pristine Bi2Fe4O9 (54.3 m2/g and 23.4 nm). Fiber optic sensor was fabricated and tested for ethanol gas with various gas concentrations (0–500 ppm). The sensitivity (defined as slope of fitted line) enhanced from 14.69 (count/%) for bare Bi2Fe4O9 to 33.94 (count/%) for Bi2Fe4O9/BC (BFOG5). The response and recovery time was 25 s and 20 s for Bi2Fe4O9/BC (BFOG5) sensor, which is higher than that of bare Bi2Fe4O9 (42 s and 33 s). Our findings pave the way for a unique hybrid Bi2Fe4O9/BC composite to be used in a highly sensitive C2H5OH gas sensor system at RT.

Effect of calcination temperature on structural, optical, and morphological properties of RAlO3 (R = La, Sm) perovskite oxides

RAlO3 (R = La, Sm) have attracted the research community due to their interesting optoelectronic properties and viable applications. The solution combustion method allows for a faster process and lower calcination temperature than the traditional solid-state method and is an economical alternative to wet chemical synthesis for producing RAlO3. This work explores the thermal, structural, morphological, optical, and electrical properties of RAlO3 (R = La, Sm) synthesised by the solution combustion method using urea as fuel. Thermogravimetric analysis—differential thermal analysis (TGA-DTA) showed the crystallization temperatures of lanthanum aluminate (LaAlO3) and samarium aluminate (SmAlO3) at 864 and 887 °C, respectively. The x-ray diffraction (XRD) and Rietveld analysis revealed the structure of LaAlO3 as rhombohedral (R-3c) and SmAlO3 as orthorhombic (Pbnm). The LaAlO3 and SmAlO3 samples calcinated at 800 °C showed crystallite size (D) of 19.26 nm and 19.06 nm, respectively. The field emission scanning electron microscopy (FE-SEM) images show a highly porous and large sheet-like morphology with voids and cracks. High resolution transmission electron microscopy (HR-TEM) images and the selective area electron diffraction (SAED) pattern show crystalline nature and the indexed planes agreed with the XRD results. The LaAlO3 and SmAlO3 samples had specific surface areas of 16.374 and 12.953 m2 g−1, respectively. The TGA-DTA results were affirmed by Fourier transform infrared spectroscopy (FT-IR) results which showed only the presence of metal-oxide bonds for materials annealed at and above 800 °C. These results were further validated by the electron dispersive x-ray spectroscopy (EDX) and the x-ray photoelectron spectroscopy (XPS) showing no additional peaks. The band gap of 5.08 and 4.82 eV were calculated from ultraviolet-visible spectroscopy (UV–vis) for LaAlO3 and SmAlO3, respectively. The results imply that the solution combustion technique using urea as fuel is a viable route for synthesising RAlO3.

Influence of aluminium in wetting characteristics of Zn-Al alloy

In this article, the effect of aluminium in Zn-5 wt%Al alloy is studied after heat treatment at 375 ⁰C focusing particularly on its effect at grain boundaries or grain boundary junctions. The understanding of such behaviour is crucial for microstructural controlling during alloy processing, ensuring better alloy performance for various applications. Using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), the microstructural and crystallographic study of the alloy was carried out. The SEM results of the annealed sample show a lenticular-shaped wetting layer corresponding to the lower energy of the grain boundary. It was observed that Zn is distributed throughout the sample, while the concentration of Al is increased at the grain boundaries as evidenced by the elemental spectra. XRD result confirms that no new phases are formed thereby confirming the formation of an Al-rich solid solution at the grain boundary. The absence of new phases indicates that aluminium in the alloy tends to lower grain boundary energy by occupying grain boundary positions, rather than forming a new compound, thereby reaching thermodynamic equilibrium. This study is important for developing advanced engineering materials with solid-state lubrication capabilities, for diverse industrial applications.

Aftermath of Ag embedding on structural, optical, and supercapacitor electrode attributes of USP-grown CuO thin films

Here, ultrasonic spray pyrolysis method (USP) was utilized to produce pure and silver doped copper oxide nanostructures on glass substrates. Thereafter, several characterization techniques were conducted on the grown samples to delve into their morphological, structural, electrochemical, and optical aspects. The mentioned analyses were carried out by performing x-ray photoelectron spectroscopy, scanning electron microscope, X-ray diffraction, electrochemical impedance spectroscopy, galvostatic charge-discharge, cyclic voltammetry, and UV–visible spectroscopy measurements. Thus, the impact of silver impurity doping on the relevant aspects of host material were recorded as well as the features of unspoiled copper oxide films. Accordingly, the samples, as indicated by X-ray diffraction results, possessed (002) preferential plane orientation of copper oxide material along with the crystallite sizes ranging from 52.52 nm to 75.02 nm due to the imperfections caused by the silver doping. The scanning electron microscope images exhibited that the silver doping did not form significant modifications in the host material morphology where nanowire-like structures observed. The presence of the suggested materials in the films was verified by the x-ray photoelectron spectroscopy. Also, the UV–visible spectroscopy measurements detected that optical absorbance edge and bandgap energy values red shifted as a result of the impurity doping. The electrochemical supercapacitors performances of the silver doped copper oxide nanostructured thin films were inspected by using the GCD, EIS, and CV. The silver doped copper oxide films demonstrated a specific capacitance value of 66 F/g at a current density of 1 A/g in 1 M KOH electrolyte. From Nyquist plot, Rs, Rcor, Rpo, Ccor and Cc were obtained as 2.327 × 103 Ω.cm2, 43.63 × 103 Ω.cm2, 4.580 × 103 Ω.cm2, 111.5 × 10-6 S*s^a. cm-2 and 101.1 × 10-6 S*s^a. cm-2, respectively. The results indicated that the electrochemically synthesized the silver doped copper oxide electrodes can be obtained and developed as an alternative electrode material for supercapacitors (SCs).

Study on the Preparation and Fluorescence Properties of Sr3Y(PO4)3: Dy3+/Tm3+

In this article, the high temperature solid-state method is adopted to synthesize Sr3Y(PO4)3: Dy3+/Tm3+ fluorescent powder. By testing and characterizing the X-ray diffraction (XRD) as well as the exciting and emitting spectrum, analyzing fluorescence lifetimes and chromaticity coordinates, we studied phase structures and optical properties of Sr3Y(PO4)3: Dy3+/Tm3+. Results of XRD show the Sr3Y(PO4)3 fluorescent powder is synthesized. Along with the increasing of adulterate concentrations, XRD peaks show overall shift. Under excitation by 352 nm, Sr3Y(PO4)3: Dy3+ exhibits blue and yellow emitting peaks at 485 nm and 575 nm, which, respectively, correspond to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions. And under excitation by 360 nm, Sr3Y(PO4)3: Tm3+ exhibits blue emitting peak at 455 nm, which corresponds to the 1D2→4F3 transition. The luminous intensity maximum of Sr3Y(PO4)3: Dy3+ occurs at 485 nm when the Dy3+ molar percentage of adulterate concentration is 0.05. The luminous intensity maximum of Sr3Y(PO4)3: Tm3+ occurs at 455 nm when the Tm3+ molar percentage of adulterate concentration is 0.05. According to the CIE, it is proved that Sr3Y(PO4)3: Dy3+ is a single matrix phosphor that can produce cold white light, and Sr3Y(PO4)3: Tm3+ is a mixed matrix phosphor that can produce blue light.

Preparation of tunable magnesium atom-doped nickel oxide films with short response time and high coloring efficiency by sol-gel method

Nickel oxide, a representative electrochromic material, is commonly employed in environmentally conscious optoelectronic devices, such as multifunctional smart windows. In this paper, novel electrochromic nickel oxide films doped with magnesium atoms were prepared on indium tin oxide (ITO) substrates by sol-gel spin-coating method, and the results of X-ray diffraction and scanning electron microscopy show that the spin-coating is unique in that the existence of a small number of cracks on the surface of the sample is conducive to the enhancement of the electrochemical properties. UV–visible spectrophotometer and electrochemical workstation were used to explore the effect of Mg-atom doping concentration on the electrochromic performance of the nickel oxide thin films, and the results showed that at an annealing temperature of 400 °C, the optical modulation amplitude of the samples with a doping concentration of 4 % reached 43.12 %, and the coloring time and the fading time were reduced to 4.0 s and 3.1 s, respectively, with an increase in the coloring efficiency to 42.25 cm2C−1. In conclusion, Mg doping has an important reference value for the study of electrochromic performance of NiO thin films, and has good prospects for electrochromic applications.

Critical microstructural modifications of Cu/Zn/Al2O3 catalyst during CO2 hydrogenation to methanol

This contribution reports the impact of the reaction pressure (1, 10, 20 and 30 bar) on the deactivation of the commercial catalyst Cu/ZnO/Al2O3 during the CO2 hydrogenation to CH3OH. The best performance was obtained at 30 bar with ≈ 30 % of initial CO2 conversion (XCO2) and CH3OH space-time-yield (STYMEOH) of 255 mgMeOH/gcat.h. Although the initial conversion decreased drastically the activity was kept along all the reaction time, ≈ 5 %. The analysis of fresh and post-reaction samples using X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Electron Microscopy (SEM-FEG, STEM, HRTEM), and Raman Spectroscopy demonstrated profound microstructural changes, characterized by phase sintering, formation of Cu-aluminate, segregation of phases, an imbalance among Cu-species, as well as the presence of coke. As the catalyst Cu/ZnO/Al2O3 has a particular microstructure, these modifications provoked the loss of the geometric configuration of the active sites, which might also originate a disturbance in the electronic interactions, resulting in activity loss. HRTEM and STEM image (dark field) of the passivated sample showed the presence of crystalline nanostructures (d < 4 nm) attributed to Cu0, surrounded by amorphous phases. STEM images of spent samples also reveals the development of hierarchical and elongated nanostructures spread on all the spent catalysts. This result foresees the co-existence of small nanoparticles (< 5 nm) with large ones in all the catalyst surface, corroborating XRD results. It is noteworthy that the hydrothermal environmental developed inside the reactor originated from the high pressure and the continuous H2O production, both which may favor the phase sintering and aluminate formation.

Effect of ultrasound/CaCl2 co-treatment on the microstructure, gelatinization, and film-forming properties of high amylose corn starch

The effect of ultrasound/CaCl2 co-treatment on aggregation structure, thermal stability, rheological, and film properties of high amylose corn starch (HACS) was investigated. The scanning electron microscopy (SEM) images revealed the number of starch fragments and malformed starch granules increased after co-treatment. The differential scanning calorimetry (DSC) results showed the co-treated HACS got a lower gelatinization temperature (92.65 ± 0.495 °C) and enthalpy values (ΔH, 4.14 ± 0.192 J/g). The optical microscope images indicated that lesser Maltase crosses were observed in co-treated HACS. The results of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) indicated ultrasound influenced the compactness of amorphous zone and CaCl2 damaged the crystalline region of HACS granules. Additionally, the rheology properties of HACS dispersion demonstrated the apparent viscosity of co-treated dispersion increased as the ultrasound time prolonged. The mechanical strength and structural compactness of HACS films were improved after ultrasound treatment. The mechanism of ultrasound/CaCl2 co-treatment improved the gelatinization and film-forming ability of HACS was that (i) ultrasound wave loosened the HACS granules shell, promoted the treatment of CaCl2 on HACS granules, and (ii) ultrasound wave improved the uniform distribution of HACS dispersion, increased the interaction between CaCl2 and starch chains during the process of film-forming.

Bismuth oxide effects on optical, structural, mechanical, and radiation shielding features of borosilicate glasses

Four glasses were synthesized using traditional melting and then the annealing process to study the possible enhancement effects of heavy metals like Bi2O3 on the borosilicate glass system for the composition ((50-x)B2O3–5SiO2–40MgO-xBi2O3 where x = 5, 10, 15, and 20). The structural features were investigated using Fourier-transform infrared (FT-IR) analysis and X-ray diffraction (XRD). Many physical and mechanical parameters have been studied. Optical absorption was measured for all samples to investigate direct and indirect transitions for optical band gap energy (Eg) and Urbach’s energy (EU) and extract various optical properties. The well-known Phy-X simulation was utilized to achieve the study’s goal of calculating the shielding parameters of various gamma energies. Based on XRD results, the amorphous nature of all samples was observed. Adding Bi2O3 instead of the B2O3 side improves the ionizing radiation shielding properties and glass transparency. For example, the MAC values at 15 keV increased from 34.75244 to 73.80841 cm2/g with adding Bi2O3. At the same time, the glass transparency rose from 62 % to 72 %. In contrast, adding Bi2O3 reduced the glass stability according to mechanical and structural properties results. For example, Young’s modulus reduced from 88.745 to 62.109 GPa with increasing Bi2O3. The packing density (Vt) also decreased from 0.606 to 0.468. Based on the results, the current glass is valid for use in a radiation shielding field.

Synthesis of LiCo1-XNiXO2 nanomaterial by hydrothermal method as cathode for lithium ion battery

The compounds of LiCoO2 (LCO) and LiCo1-xNixO2 (LCNO), with (x=0,0.25,0.5,0.75,1) were synthesized as cathode active material for lithium–ion batteries using hydrothermal technique in this study. Structure and morphology characterization were conducted for all prepared samples. The crystalline results indicate that both LCO and LCNO possess a rhombohedral structure, while the morphology results show irregular shapes. Electrochemical tests were carried out for LiCoO2 and LiCo0.25 Ni0.75O2 samples only. From the electrochemical measurements, the LiCo0.25 Ni0.75O2 demonstrate higher charge and discharge capacities compared to the LiCoO2 electrode, findings which are consistent with the electrochemical impedance spectroscopy (EIS) results. The X-ray diffraction (XRD) results of both the prepared Lithium Cobalt Oxide (LCO) and Lithium Cobalt Nickel Oxide (LCNO) samples reveal characteristic peaks at specific angles (2θ) indicating crystallographic planes. For LCO, peaks were observed at 18.96°, 37.40°, 38.35°, 39.07°, 45.29°, 49.45°, and 59.62° corresponding to crystallographic planes (003), (101), (006), (012), (104), (015), and (107) respectively. These peaks confirm the formation of a rhombohedral LiCoO2 nanostructure with space group (R-3m no.166), consistent with standard data (JCPDS 00-016-0427). The EDX spectra of the synthesized Lithium Cobalt Oxide (LCO) and Lithium Cobalt Nickel Oxide (LCNO) were analyzed. The results showed the presence of oxygen (O), cobalt (Co), and nickel (Ni) elements. However, the peak corresponding to lithium (Li) was not visible due to its low activation energy. Finally, the synthesis and characterization of LiCoO2 (LCO) and LiCo1-xNixO2 (LCNO) compounds were conducted, with electrochemical tests indicating superior performance of LiCo0.25 Ni0.75O2 over LiCoO2

SrAl2O4: Ce: Synthesis and dosimetric characteristics of a new highly sensitive TL phosphor for dosimetry

Strontium aluminate (SrAl2O4) doped with different Ce concentrations was synthesized by the solid-state reaction method to find the best thermoluminescent response. The crystal structure of the material has been analyzed by Rietveld refinement of X-ray diffraction (XRD) results. The effects of different dopant concentrations and thermal annealing regimes on TL sensitivity and the optimum conditions for producing dosimeters with superior sensitivity to commercial dosimeters were investigated. It has been shown that the maximum TL sensitivity is obtained at a concentration of 0.3 mol% Ce and a heat treatment at 1000 °C for 2 h. The TL glow curve of Ce-doped strontium aluminate (SrAl2O4) pellets shows three TL peaks at 90, 150, and 250 °C. The dosimetric characteristics of the new material examined in this work are linear response in the dose range with applications in personal and environmental dosimetry; TL sensitivity; minimum detection dose; reproducibility; energy dependence; and TL signal fading. Based on the results obtained, the synthesized material is a dosimeter with a sensitivity 2.44 times higher than the commercial dosimeter TLD-100 (LiF:Ti,Mg).