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Giant cell tumor (GCT) is an intermediate malignant bone tumor which mostly involves long extremity bones, less commonly involving the spine with sacral predominance. Cervical spine involvement is rare. According to literature, the selective approach for the treatment of GCT is en bloc resection with spinal reconstruction. For unusual sites, such as cervical region, which is a mobile spinal segment and critically proximate to the cervical spinal cord, great vessels, and vital organs, it is almost impossible to perform the selective approach for treatment. Alternative approaches in such situations are under investigations. We present a case of C2 vertebral body GCT, who was treated with polymethylmethacrylate intravertebral injection and was followed by adjuvant therapy with denosumab. A 16-year-old boy without any past medical history presented with progressive suboccipital and axial neck pain since 3 months earlier, which had not responded to conservative treatments. There was no neurologic deficit, and pain was significantly controlled. In the 1-year follow-up, no complication and tumor recurrence was seen. Vertebroplasty with bone cement for lytic spinal GCT lesions, followed by adjuvant therapy with denosumab, not only is a less invasive treatment but also has good results in spinal stability, patient recovery, and 12-month recurrence. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) system has gradually become a research focus in the field of renewable energy power generation, and the output efficiency of PV system is the major concern of researchers. There are obvious non-linear characteristics in the output of PV system, and it will be greatly affected by the external environment. For achieving the maximum output power, PV system must operate under the guidance of maximum power point tracking (MPPT) methods. The tracking time and accuracy of these methods need to be improved. Therefore, this study contributes to increasing the output efficiency of PV system by improving the tracking time and accuracy with using Fuzzy Gain Scheduling of Proportional-Integral-Derivative (FGS-PID) regulator in the grid-connected mode. The suggested adaptive FGS-PID scheme is implemented using two-level control system architecture, combining the benefits of fuzzy logic as well as conventional PID regulator. Ziegler–Nichols tuning method is employed to select the initial values of PID gains. In the simulations of PV system under the varying irradiance and temperature, the tracking speed and tracking accuracy of FGS-PID (scaling factors) were higher than those of ANN, ANFIS, Fuzzy, INC, P&O, PID, and FGS-PID methods. In summary, FGS-PID (scaling factors) has better performance in tracking time and accuracy than other comparison algorithms. It can improve the output efficiency of PV system in practical application. [ABSTRACT FROM AUTHOR]

To enhance the interfacial bonding between the graphene oxide nanoplatelets (GONs) and epoxy (EP) matrix, two different types of silane coupling agents (amino‐ and EP‐silane) were applied to the GONs‐EP nanocomposites. The effects of the silane compound type and silanized GON loading (0.1–0.5 wt% at an interval of 0.2) on the dry‐sliding wear response of GONs‐EP nanocomposites were then studied. The wear tests were conducted under 20 N load and 1000 m sliding distance. The results showed that the wear properties were remarkably improved by the incorporation of silanized GONs to the matrix, and the best wear behavior was obtained at 0.3 wt% silanized GONs. Most importantly, the amino‐silane coupling agent was shown to be more effective in enhancing the wear resistance of the GONs‐EP nanocomposites. After the wear tests, the composite surfaces were studied by scanning electron microscopy to find the predominant mechanisms. [ABSTRACT FROM AUTHOR]

Summary: Microgrids (MGs) are known as suitable options to accommodatethe high penetration of renewable energies, like solar and wind. MGs have provided the requirements of controlling and adjusting these sources. In addition, batteries are becoming indispensable components of MGs because of their capabilities in addressing the renewable energies' power output intermittency. In MGs, the problem of smart energymanagement along with battery sizing has been introduced as the necessity to ensure the efficient use of renewable sources and decrease traditional fossil‐fuel‐based generation technology penetration level in power systems. Accordingly, a novel method is presented in this paper to effectively address the above‐mentioned requirements, utilizing the modified shuffled frog leaping algorithm (MSFLA), applied to different case studies. The results, obtained from the numerical simulation, are compared to several well‐established optimization approaches to verify the performance of MSFLA. In terms of computational efficiency and quality of the obtained solution, the MSFLA has demonstrated promising outcomes, together with superior performance in comparison with other algorithms. The results show that the presented framework, including the battery sizing, would be very beneficial to minimize the operating cost of MGs. [ABSTRACT FROM AUTHOR]

TA series of Graphene Oxide/ Polyacrylamide (GO/PAM) super-elastic nanocomposites with different amounts of Graphene Oxide Nanosheets (GONSs) (0.5, 1, 1.5, and 2 wt. %) were synthesized using an insitu polymerization in an aqueous medium in this paper. To this end, we proposed a method for obtaining super-elastic nanocomposites with a high dispersion of GONSs in the PAM chains as well as in a rapid synthesis. Fine adaptability, powerful inner interaction between embedded GONSs into the PAM chains, and remarkable enhancement of mechanical and thermal properties of synthesized GO/PAM super-elastic nanocomposites can be considered as the unique characteristics of this synthesis method in a short time. In this study, GONSs were prepared by a modified Hummer’s procedure at ambient temperature. Fourier Transform Infrared (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), thermo-Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) were employed to characterize the internal network structure of GONSs, PAM, and GO/PAM nanocomposites. XRD investigation indicated the increase of the interlayer spacing of GONSs. The exfoliation and dispersion of GONSs in the PAM matrix were studied by XRD and FESEM. The formation of oxygen-including groups on the surface of GONSs and hydrogen linking between GONSs and PAM was confirmed by FT-IR spectra and DTA. Atomic Force Microscopy (AFM) was used to evaluate the thickness of the synthesized GONSs that was measured to be about 6.85 nm. Ultraviolet-Visible (UV/vis) spectroscopy illustrated the high percent of oxidation with more oxygen-including groups on the GONSs basal surface. Raman spectroscopy was also utilized to determine the induced disorder degree in the synthesized graphene oxide and distinguish the number of its layers. Thermal properties curves of GO/PAM nanocomposites represented an improvement trend in degradation temperature and a remaining amount up to GO-loaded (1.5 wt. %). The addition of GONSs also showed the significant improvement of viscoelastic behavior in PAM chains. The highest storage modulus (G’; 6.42 MPa) and loss modulus (G”; 0.98 MPa) are related to GO/PAM nanocomposite with 1.5 wt. % GO-loading. Based on the empirical result, the GONSs could remarkably enhance the thermal conductivity of PAM which was measured to be about 0.49 W.m-1.K-1. Thermal conductivity of GO1.5/PAM nanocomposite was about 0.9 W.m-1.K-1 that showed 84 % increase compared to the PAM. [ABSTRACT FROM AUTHOR]

Grafting 6-aminopenicillanic acid (6-APA) onto superparamagnetic γ-Fe2O3@SiO2 nanocomposites led to the production of 6-APA/γ-Fe2O3@SiO2 as a novel heterogeneous nanocatalyst. Protonation and deprotonation of 6-APA/γ-Fe2O3@SiO2 nanocomposites were investigated using quantum mechanical calculations. The behaviour of bifunctionality on this catalyst was examined and the results showed that it acts as an acid–base bifunctional system, and the reaction proceeds very well under mild and ambient conditions. The deprotonation of the COOH group is easier than the NH and NH2 groups with respect to the energy data and the results of the molecular electrostatic potential (MEP) analyses. In the presence of the nanocomposite, the protonation of the NH2 group is more favourable than the NH group. It was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometery (VSM), thermo-gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR). This reaction is not only kinetically stable but is also a spontaneous reaction and thermodynamically favored. The superparamagnetic nanocomposite was used in the preparation of 1,4-dihydropyrano[2,3-c]pyrazole derivatives under a one-pot multicomponent reaction. The nanocomposite was recyclable for at least 10 cycles without any loss in the activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The study distinguished various pyrrhotite superstructures in Cu-Au ores. • Limited resolution in XRD hindered differentiation of pyrrhotite superstructures. • Magnetic colloid technique (MCT) identified magnetic and nonmagnetic pyrrhotite. • Kikuchi patterns helped determine 4C, 5C and 6C pyrrhotite superstructures. • The combination of XRD, MCT, EDS and EBSD identified pyrrhotite superstructures. Pyrrhotite exhibits diverse non-stoichiometric superstructures with varied surface reactivities, causing contradictory flotation behaviors in industrial processes. The challenges in managing pyrrhotite in processing plants stem from the lack of systematic mineralogical techniques to distinguish its superstructures in low-grade ore samples without any preprocessing, such as purification or manual sample picking. This study established a comprehensive technique to differentiate between pyrrhotite superstructures in low-grade metal sulfide ores using spectroscopic and microscopic methods. The examined samples came from a natural copper–gold orebody from Western Australia and the flotation concentrate of the ore. Initial identification of pyrrhotite through XRD confirmed the presence of pyrrhotite in the samples but failed to discern magnetic and nonmagnetic pyrrhotite superstructures due to the samples' low pyrrhotite content and XRD peak overlaps. In this regard, magnetic colloid technique (MCT) was utilized to effectively identify the presence of both magnetic and nonmagnetic pyrrhotite superstructures in the samples. Energy-dispersive X-ray spectroscopy (EDS) analysis revealed the Fe:S (at.%) ratio ranging from 0.840 to 0.930 for both the ore and the flotation concentrate, affirming the presence of both magnetic and nonmagnetic pyrrhotite with possible 4C, 5C and 6C superstructures. Based on the information obtained from XRD, MCT and EDS, Electron Backscatter Diffraction (EBSD) analysis successfully solved the challenge of identifying pyrrhotite superstructures. By comparing Kikuchi patterns from various zones with different Fe:S ratios to reference patterns, the EBSD confirmed the presence of 4C, 5C and 6C pyrrhotite superstructures in the examined samples. This methodology establishes a comprehensive framework for identifying pyrrhotite superstructures in complex ore samples, offering insights for industrial applications. [ABSTRACT FROM AUTHOR]