<abstract><title style='display:none'>Abstract</title> Graphene has achieved a great amount of popularity and interest from the science world because of its extraordinary physical, mechanical and thermal properties. Graphene is an allotrope of carbon, having one-atom-thick planar sheets of sp2 bonded carbon atoms densely packed in a honeycomb crystal lattice. Many methods to synthesize graphene have been developed over a short period and we believe it is necessary to create a list of the most notable approaches. This article focuses on the methods to synthesize graphene in an attempt to summarize and document advancements in the synthesis of graphene research and future prospects.</abstract>

Graphene synthesis: a Review

<abstract><title style='display:none'>Abstract</title>A simple oxidation synthesis route was developed for producing magnetite nanoparticles with controlled size and morphology. Investigation of oxidation process of the produced magnetite nanoparticles (NP) was performed after synthesis under different temperatures. The phase transformation of synthetic magnetite nanoparticles into maghemite and, henceforth, to hematite nanoparticles at different temperatures under dry oxidation has been studied. The natural magnetite particles were directly transformed to hematite particles at comparatively lower temperature, thus, maghemite phase was bypassed. The phase structures, morphologies and particle sizes of the produced magnetic nanoparticles have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX) and BET surface area analysis.</abstract>

Department of Physics, University of Science and Technology Bannu, Pakistan

Department of Physics, Kohat University of Science and Technology, Kohat, Pakistan

Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS Institute of Information Technology, Lahore, Pakistan

Transformation mechanism of magnetite nanoparticles

<abstract><title style='display:none'>Abstract</title>Raman spectroscopy is a most often used standard technique for characterization of different carbon materials. In this work we present the Raman spectra of polycrystalline diamond layers of different quality, synthesized by Hot Filament Chemical Vapor Deposition method (HF CVD). We show how to use Raman spectroscopy for the analysis of the Raman bands to determine the structure of diamond films as well as the structure of amorphous carbon admixture. Raman spectroscopy has become an important technique for the analysis of CVD diamond films. The first-order diamond Raman peak at ca. 1332 cm−1 is an unambiguous evidence for the presence of diamond phase in the deposited layer. However, the existence of non-diamond carbon components in a CVD diamond layer produces several overlapping peaks in the same wavenumber region as the first order diamond peak. The intensities, wavenumber, full width at half maximum (FWHM) of these bands are dependent on quality of diamond layer which is dependent on the deposition conditions. The aim of the present work is to relate the features of diamond Raman spectra to the features of Raman spectra of non-diamond phase admixture and occurrence of other carbon structures in the obtained diamond thin films.</abstract>

Study of CVD diamond layers with amorphous carbon admixture by Raman scattering spectroscopy

<abstract><title style='display:none'>Abstract</title>Vanadium dioxide VO2 has been paid in recent years increasing attention because of its various applications, however, its oxidation resistance properties in air atmosphere have rarely been reported. Herein, VO2(B) nanobelts were transformed into VO2(A) and VO2(M) nanobelts by hydrothermal route and calcination treatment, respectively. Then, we comparatively studied the oxidation resistance properties of VO2(B), VO2(A) and VO2(M) nanobelts in air atmosphere by thermo-gravimetric analysis and differential thermal analysis (TGA/DTA). It was found that the nanobelts had good thermal stability and oxidation resistance below 341 °C, 408 °C and 465 °C in air, respectively, indicating that they were stable in air at room temperature. The fierce oxidation of the nanobelts occurred at 426, 507 and 645 °C, respectively. The results showed that the VO2(M) nanobelts had the best thermal stability and oxidation resistance among the others. Furthermore, the phase transition temperatures and optical switching properties of VO2(A) and VO2(M) were studied by differential scanning calorimetry (DSC) and variable temperature infrared spectra. It was found that the VO2(A) and VO2(M) nanobelts had outstanding thermochromic character and optical switching properties.</abstract>

VO2(B) conversion to VO2(A) and VO2(M) and their oxidation resistance and optical switching properties

<abstract xml:lang="en"><title style='display:none'>Abstract</title>In this research work, we prepared γ-Fe2O3 nanoparticles by thermal-decomposition of Fe3O4. The Fe3O4 nanoparticles were synthesized via co-precipitation method at room temperature. This simple, soft and cheap method is suitable for preparation of iron oxide nanoparticles (γ-Fe2O3; Fe3O4). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), vibrating sample magnetometer and differential scanning calorimeter (DSC). The XRD and FT-IR results indicated the formation of γ-Fe2O3 and Fe3O4 nanoparticles. The TEM images showed that the γ-Fe2O3 and Fe3O4 were spherical, and their size was 18 and 22 nm respectively. Magnetic properties have been measured by VSM at room temperature. Hysteresis loops showed that the γ-Fe2O3 and Fe3O4 nanoparticles were super-paramagnetic.</abstract>

Synthesis of maghemite (γ-Fe2O3) nanoparticles by thermal-decomposition of magnetite (Fe3O4) nanoparticles

<abstract><title style='display:none'>Abstract</title>Thin films of manganese-doped cadmium oxide (CdO:Mn) with different Mn-doping levels (0, 1, 2, 3 and 4 at.%) were deposited on glass substrates by employing an inexpensive, simplified spray technique using a perfume atomizer at 375 °C. The influence of Mn incorporation on the structural, morphological, optical and electrical properties of CdO films has been studied. All the films exhibit cubic crystal structure with a (1 1 1) preferential orientation. Mn-doping causes a slight shift of the (1 1 1) diffraction peak towards higher angle. The crystallite size of the films is found to decrease from 34.63 nm to 17.68 nm with an increase in Mn doping concentration. The CdO:Mn film coated with 1 at.% Mn exhibit a high transparency of nearly 90 % which decreases for higher doping concentration. The optical band gap decreases with an increase in Mn doping concentration. All the films have electrical resistivity of the order of 10−4 Ω·cm.</abstract>

Effect of doping concentration on the structural, morphological, optical and electrical properties of Mn-doped CdO thin films

<abstract>
<title style='display:none'>Abstract</title>
In this work, NiO–ZnOnanocomposite (NC)was prepared through a facile, low-temperature,sol–gel route. Zinc acetate dihydrate, nickel chloride hexahydrate, cetyltrimethyl ammonium bromide (CTAB), and citric acid were used in the synthesis of the material. Then, the sample was kept in the muffle furnace at a temperature of 600°C for 2 h. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), UV–Visible spectroscopy, and photocatalytic and antifungal investigations were used to characterize the synthesized nanocrystallites. The XRD data showedthe polycrystalline hexagonal ZnO nanoparticles and cubic NiO crystallites. FTIR studies confirmed the presence of Zn-O and Ni-O bonds in the sample. The FESEM analysis showed the morphology of nanocrystallitescharacterized by their homogeneous shape and size. The absorbance curves from the UV–Visible spectroscopy investigation revealed the bandgap of 3.17 eV. The research findings demonstrate that the NiO–ZnO NC possesses the significant level of selected microbial pathogens. Industrial dyesmake water unhealthy for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable, and causes a severe threat to human health and environmental safety. Hence, it is necessary to develop efficient and environmentally friendly technology to remove MB from wastewater. The ZnO–NiO NC degraded the MB dye pollutant under visible irradiation (125 W), according to photocatalytic tests. After 120 min of exposure, the photocatalytic investigations demonstrated 75% degradation efficiency.
</abstract>

Microstructural, antifungal and photocatalytic activity of NiO–ZnO nanocomposite

<abstract>
<title style='display:none'>Abstract</title>
Nanobainitic steels exhibit an exceptional combination of high strength, good plasticity, impact toughness, and wear resistance. They are suitable for the production of large mass components through the open-die forging process. Subsequently, the forgings are air-cooled. An obstacle of this method is the extended time required for the large forgings to undergo a bainitic transformation, making the industrial implementation of this process economically unjustifiable. Nevertheless, nanobainitic steels also allow for the open-die forging of small batches of structural elements with high property requirements. A technological limitation lies in the necessity of performing a series of operations, leading to a prolonged processing time dependent on the shape of the product and the degree of deformation. Therefore, inter-operational reheating is often necessary, incurring costs and time consumption. This is particularly relevant to forgings with a mass ranging from a few to several dozen kilograms, which, due to their low thermal capacity, rapidly dissipate heat to the surroundings and tools. Designing an economical process with a limited number of reheating cycles requires advanced knowledge of material behavior under thermo-mechanical deformation parameters, including boundary conditions where a significant decrease in plasticity occurs and the risk of crack initiation. To obtain this information, a comprehensive analysis of the influence of thermo-mechanical parameters applied during the deformation of nanobainitic steel at relatively low temperatures on the flow characteristics and crack formation was conducted. To achieve this goal, the Digital Image Correlation method, the finite element method modeling considering damage criteria, and the macrostructural evaluation of deformed specimens were employed.
</abstract>

Evaluation of cracking risk of 80MnSi8-6 nanobainitic steel during hot forging in the range of lower temperature limits

<abstract>
<title style='display:none'>Abstract</title>
Enhancing the service life of natural rubber (NR) products, including antioxidants, is crucial to prevent rubber degradation and enhance its oxidation resistance. Phenolic antioxidant 2246 and cerium complex of p-amino salicylic acid (PAS-Ce) are utilized as NR antioxidants. Numerous studies have qualitatively analyzed the antioxidant mechanisms of these compounds. Building upon this perspective, this study quantitatively assessed the protective mechanisms of these antioxidants by combining experimental data with molecular simulations. Additionally, it compared their impacts on the thermal oxidative aging performance of NR. The findings revealed that the PAS-Ce/NR system exhibited the highest mechanical performance retention following multiple days of thermal-oxidative aging. Analyzing the PAS-Ce/NR system through ATR-FTIR and DTA techniques demonstrated that it had the lowest C=O content after thermal-oxidative aging. Furthermore, calculating the activation energy required for thermal-oxidative aging decomposition using the Kissinger and FWO methods indicated that PAS-Ce/NR had the highest activation energy, suggesting superior inhibitory effects against thermal-oxidative aging. Quantum mechanical simulations also illustrated that the dissociation energy of the O-H bond in antioxidants 2246 and PAS-Ce was lower than that of the C-H bond in NR. However, PAS-Ce exhibited a quicker capture of radical species, effectively delaying the oxidation reaction rate of NR molecular chains and thus more efficiently inhibiting the aging process. These insights contribute significantly to comprehending the antioxidative mechanisms in NR aging.
</abstract>

Mechanical properties and quantum mechanical simulations of natural rubber composites with cerium complexes under aging conditions

<abstract>
<title style='display:none'>Abstract</title>
It is essential to retrofit deep beams with shear inadequacies because these beams, although they have the same shear and flexural reinforcements as ordinary beams, are more susceptible to shear failure. Hence, it is of great significance to overcome the shear weaknesses in deep beams. This research paper aims to experimentally examine the effectiveness of near-surface mounted (NSM) carbon fiber reinforced polymer (CFRP) for retrofitting reinforced concrete (RC) deep beams subjected to shear forces. The study involved three different types of specimens. The first specimen was constructed with concrete throughout its span and included shear stirrups. The second specimen was divided into two halves, with one half lacking shear reinforcements and the other half having them. The third specimen had steel web reinforcement in one half of the span, while the other half was strengthened using NSM CFRP U-wrap strips and externally bonded horizontal CFRP strips. The proposed strengthening method significantly increased the shear strength of the deep beams, surpassing that provided by steel web reinforcement alone. Furthermore, the NSM CFRP strengthened specimen exhibited a change in failure mode from shear to flexural failure. In comparison to the control beam without stirrups, the beams strengthened with NSM CFRP U-wrap strips demonstrated an impressive 82% improvement in shear strength, while the beam with shear reinforcement showed a 23 % enhancement in load capacity. The proposed strengthened scheme is capable of enhancing the structural performance and load-carrying capacity effectively. A finite element model was generated utilizing ABAQUS software to simulate the behavior of the tested deep beams and verified against the experimental outcomes. The numerical models successfully predicted the behavior of the RC deep beams strengthened with NSM CFRP when compared to the experimental data.
</abstract>

Shear strengthening of deficient RC deep beams using NSM FRP system: Experimental and numerical investigation

<abstract>
<title style='display:none'>Abstract</title>
Sulfate attack is one of the most significant durability issues for cement-based grouts, which are widely used to repair concrete structures in sulfate-rich environments. The purpose of this study was to investigate the impact of nano-SiO2 emulsion on the sulfate resistance of cement-based grouts. The durability of the mixes was evaluated on the basis of weight loss and compressive strength. X-ray diffraction (XRD) and scanning electron microscopy (SEM) of hardened grout matrix were used to analyze the hydration products and microstructure of the hardened grout matrix. The results indicate that the hydration degree of nano-SiO2-modified samples is higher than that of the control sample. The compressive strength from highest to lowest was 16 NSE, 10 NSE, NSP, and the control sample. The XRD and SEM results suggest that the deterioration of properties may be attributed to the formation and growth of ettringite (AFt) crystals, which may result in crack generation and extension and in the corrosion of gypsum, leading to exfoliation. The addition of nano-SiO2 to cement-based grouts through a preprepared emulsion, which facilitates dispersion within the cement matrix, has the potential to reduce AFt and gypsum contents, enhance microstructure density, decrease the migration channels of <inline-formula><alternatives><inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_msp-2024-0010_ieq_001.png"/><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>SO</mml:mtext></mml:mrow><mml:mn>4</mml:mn><mml:mrow><mml:mn>2</mml:mn><mml:mo>−</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math><tex-math>\[\text{SO}_{4}^{2-}\]</tex-math></alternatives></inline-formula>, and ultimately improve the resistance to sulfate attack. This work will provide a novel route to enhance the sulfate resistance of cement-based grouts, which may be serviced in a sulfate-rich environment.
</abstract>

The influence of nano-SiO2 emulsion on sulfate resistance of cement-based grouts

<abstract>
<title style='display:none'>Abstract</title>
The KOBO extrusion process is an unconventional method of extrusion based on the phenomenon of superplasticity as an effect of a special state caused by the oscillatory motion of the die at a certain angle a certain frequency. It significantly lowers the extrusion force and makes it possible to extrude lightweight metals and alloys (e.g. aluminum and magnesium alloys) in cold extrusion with high extrusion ratios compared to conventional hot extrusion.
This work studies the influence of the tool (die) geometry on process realization parameters and the properties of the extrudate. Experimental studies of cold KOBO extrusion were performed using dies with different face portion geometry. The obtained extrudate obtained from EN-AW 7075 aluminum billets was examined for mechanical properties and macro/microstructure, showing that, with adequate modifications to the tool face part geometry, it is possible to lower the extrusion force and obtain extrudate with desired properties.
</abstract>

Analysis of the influence of dies geometry on the process extrusion force and properties of the extrudate obtained in the process of cold extrusion of 7075 aluminum alloy by the KOBO method

<abstract xml:lang="en"><title style='display:none'>Abstract</title>Auxetic materials are endowed with a behavior that contradicts common sense, when subjected to an axial tensile load they increase their transverse dimension. In case of a compression load, they reduce their transverse dimension. Consequently, these materials have a negative Poisson’s ratio in such direction. This paper reviews research related to these materials. It presents the theories that explain their deformation behavior and reveals the important role represented by the internal structure. Their mechanical properties are explored and some potential applications for these materials are shown.</abstract>

Auxetic materials — A review

<abstract xml:lang="en"><title style='display:none'>Abstract</title>Duck eggs are one of the most versatile cooking ingredients in which residue eggshells are discarded. Raw duck eggshells were calcined at temperatures between 300 to 900 °C, for 1, 3, and 5 h. Both the raw and calcined duck eggshells were characterized by FTIR, STA, XRD, XRF, TEM, BET, a particle size analyzer, and an impedance analyzer. The proper calcination conditions are: 900 °C and 1 h, yielding calcium oxide with a purity of 99.06 % w/w. The calcium carbonate of the rhombohedral form (CaCO3) transforms completely into the calcium oxide or lime of the face centered cubic form (CaO) at 900 °C, as shown by XRD diffraction patterns. The transmission electron microscopy (TEM) images of the calcium oxide reveal a moderately good dispersion of nearly uniform particles. The calcium oxide has a white color, a spherical shape, high porosity, and narrow particles size distribution. The percentage of ceramic yield of the calcium oxide is 53.53, as measured by STA (TG-DTA-DTG). The calcium oxide has a N2 adsorption-desorption isotherm indicating the meso-porosity range. The dielectric constant and the electrical conductivity of the calcined calcium oxide are 35 and 1:0×10−6(Ω·m)−1, respectively, at the frequency of 500 Hz.</abstract>

Center for Advanced Studies in Industrial Technology and The Materials Engineering Department, Faculty of Engineering, Kasetsart University, Bangkok, 10900, Thailand

The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok, 10330, Thailand

Preparation and properties of calcium oxide from eggshells via calcination

<abstract xml:lang="en"><title style='display:none'>Abstract</title>Silver colloidal nanoparticles were prepared according to the chemical reduction method in which the ascorbic acid was used as a reducing agent and sodium citrate as a stabilizing agent. The absorption spectra of all prepared samples obtained using the UV-Vis spectrophotometer showed a surface plasmon peak at a wavelength of about 420 nm. The size of the silver nanoparticles was controlled by changing the pH values of the reaction system. At high pH, smaller size silver nanoparticles were obtained compared to low pH values. This difference can be attributed to the difference in the reduction rate of the precursor. In addition to the inverse proportionality between the size and the pH value it is clear that increasing the pH value enables us to obtain spherical nanoparticles while at low pH, rods and triangular particle shapes were formed. Poor balance between nucleation and growth processes could be the cause of this result.</abstract>

Physics Department, Jordan University of Science and Technology, Irbid, Jordan

Al-Huson University College, Al-Balqa applied University, Huson-Irbid, Jordan

pH effect on the aggregation of silver nanoparticles synthesized by chemical reduction

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