Search

Nanocrystalline calcium titanate (CaTiO3) doped with cerium ions (0.02 mol%) was synthesized via hydrothermal method and its luminescent properties were studied for gamma dosimetry. For the synthesized samples, the best luminescent response was achieved after annealing at 700 °C for 8 h. The synthesis was confirmed via XRD technique yielding the cyrstallite size of 22 nm for the most intense peak (121). The surface morphology was studied via scanning electron microscopy (SEM) yielding the grain size of 12 µm. The strong IR absorptions appeared at 700 cm−1 and 712 cm−1 attributed to bending mode of vibrations changing angle between Ti–O–Ti for CaTiO3 and CaTiO3:Ce respectively, as confirmed via Fourier-Transform Infrared (FTIR) Spectroscopy. Thermoluminescent (TL) response of undoped and doped samples was studied by Mikrolab RA94 TLD Reader-Analyzer having heating rate 10 °C/s, for absorbed doses 0–20 mGy from 137Cs γ-source having a dose rate 100 mSv/h. The found values at 662 keV for the photon-sensing parameters, i.e., mass attenuation coefficients (μ/ρ), mass-energy attenuation coefficient (μen/ρ), effective atomic number for photon interaction (Zeff,PI) and effective atomic number for total photon energy absorption (Zeff,PEA) were 0.07030882 cm2/g, 0.0280245 cm2/g, 13.9 and 13.4 respectively. Thus, synthesized nanophosphor has shown excellent thermoluminescent dosimetric response for gamma radiation sensing in the selected dose range. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) derived from mandarin peel biochar (MBC) at different pyrolysis temperatures (200, 400, 600, and 800 °C) have been synthesized and characterized. This high-value transformation of waste materials into fluorescent nanoprobes for environmental monitoring represents a step forward towards a circular economy. In this itinerary, CDs produced via one-pot hydrothermal synthesis were utilized for the detection of copper (II) ions. The study looked at the spectroscopic features of biochar-derived CDs. The selectivity of CDs obtained from biochar following carbonization at 400 °C (MBC400-CDs towards various heavy metal ions resulted in considerable fluorescence quenching with copper (II) ions, showcasing their potential as selective detectors. Transmission electron microscopic (TEM) analysis validated the MBC-CDs' consistent spherical shape, with a particle size of <3 nm. The Plackett–Burman Design (PBD) was used to study three elements that influence the F0/F ratio, with the best ratio obtained with a pH of 10, for 10 min, and an aqueous reaction medium. Cu (II) was detected over a dynamic range of 4.9–197.5 μM and limit of detection (LOD) of 0.01 μM. Validation testing proved the accuracy and precision for evaluating tap and mountain waters with great selectivity and no interference from coexisting metal ions. [ABSTRACT FROM AUTHOR]

Among the serious environmental problems that attracted much attention from the broader public is the high toxicity of dioxins. Considerable efforts have been made to develop techniques and materials that could help in their efficient removal from the environment. Due to its high specific surface area, numerous active sites, and outstanding structural and electronic properties, antimonene is considered for a variety of potential applications in different fields such as energy storage, electrocatalysis, and biomedicine. The present study adds to this portfolio by suggesting antimonene as a promising candidate for dioxin capture. Using density functional theory calculations, we studied the adsorption of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on pristine as well as Ca-, Ti-, and Ni-doped antimonene. Three spatial configurations of the adsorption of TCDD on antimonene were analyzed. The results obtained from the calculation of adsorption energies, charge transfer, and densities of states provide evidence that antimonene outperforms other nanomaterials that have been previously suggested for dioxin capture applications. Therefore, we propose these substrates (i.e., pristine and doped antimonene) as potential capture agents for removing such toxic organic pollutants. [ABSTRACT FROM AUTHOR]

Efforts from the scientific community and the private sector are required to lower the costs of large‐scale production of nanomaterials (NMs) to enhance their commercialization. In this work, the computer‐aided process design of large‐scale NM synthesis procedures is comprehensively reviewed. Moreover, a generalized process flow diagram for all large‐scale production processes was constructed by surveying numerous scalable experimental procedures reported in the literature. Previous studies reporting simulation cases of large‐scale production processes of NMs and nanocomposites (NCs) are also reviewed based on the type of material produced, e.g., oxides, sulfides, carbonaceous materials, organic materials, metals, and other types of NMs. Finally, technical insights from classical chemical engineering specializations, such as altering process configurations, optimizing process variables, integrating chemical processes, utilizing renewable energy sources, conducting computational calculations, employing machine learning techniques, and studying the process's environmental impact, are reviewed for large‐scale NMs and NCs synthesis. [ABSTRACT FROM AUTHOR]

Bilayer electrospun fibers aimed to be used for skin tissue engineering applications were fabricated for enhanced cell attachment and proliferation. Different ratios of PHBV-PLLA (70:30, 80:20, and 90:10 w/w) blends were electrospun on previously formed electrospun PHBV membranes to produce their bilayers. The fabricated electrospun membranes were characterized with FTIR, which conformed to the characteristic peaks assigned for both PHBV and PLLA. The surface morphology was evaluated using SEM analysis that showed random fibers with porous morphology. The fiber diameter and pore size were measured in the range of 0.7 ± 0.1 µm and 1.9 ± 0.2 µm, respectively. The tensile properties of the bilayers were determined using an electrodynamic testing system. Bilayers had higher elongation at break (44.45%) compared to the monolayers (28.41%) and improved ultimate tensile strength (7.940 MPa) compared to the PHBV monolayer (2.450 MPa). In vitro cytotoxicity of each of the scaffolds was determined via culturing MC3T3 (pre-osteoblastic cell line) on the membranes. Proliferation was evaluated using the Alamar Blue assay on days 3, 7, and 14, respectively. SEM images of cells cultured on membranes were taken in addition to bright field imaging to visually show cell attachment. Fluorescent nuclear staining performed with DAPI was imaged with an inverted fluorescent microscope. The fabricated bilayer shows high mechanical strength as well as biocompatibility with good cell proliferation and cell attachment, showing potential for skin substitute applications. [ABSTRACT FROM AUTHOR]

Piezoelectricity is pivotal for applications in micro/nanoelectromechanical (MEMS/NEMS) systems. Inducing such a property into the two-dimensional Sc2CTT′ MXenes (where T and T′ are the functionalization atoms) via homogeneous and heterogeneous surface functionalization is explored. The functionalization atoms T and T′ located at the upper and lower surfaces, respectively, are identical in the case of homogeneous functionalization, while they differ in the case of heterogeneous functionalization. Upon T and T′ exchange, an additional reverse heterogeneous configuration is generated. The heterogeneous functionalization of Sc2CT2 induces extraordinary in-plane and out-of-plane piezoelectric effects owing to symmetry breaking. Interestingly, both heterogeneous and its reverse configurations show approximately identical geometrical, energetic, and even elastic properties, but rather different piezoelectric coefficients. The obtained piezoelectric effect is more than ten times larger than the experimentally measured piezoelectricity of a MoS2-monolayer. Our study suggests a way toward more efficient nanoscale piezoelectric devices based on the Sc2C MXenes for energy conversion and storage. [ABSTRACT FROM AUTHOR]

The correlated exciton-vibrational dynamics of the Fenna-Matthews-Olson (FMO) complex is studied using Multi-layer Multi-configuration Time-dependent Hartree (ML-MCTDH) wavepacket propagation. Exciton populations and coherences are shown to be sensitive to the details of the spectral density.

Li-ion batteries (LIBs) and Na-ion batteries (SIBs) are deemed green and efficient electrochemical energy storage and generation devices; meanwhile, acquiring a competent anode remains a serious challenge. Herein, the density-functional theory (DFT) was employed to investigate the performance of V4C3 MXene as an anode for LIBs and SIBs. The results predict the outstanding electrical conductivity when Li/Na is loaded on V4C3. Both Li2xV4C3 and Na2xV4C3 (x = 0.125, 0.5, 1, 1.5, and 2) showed expected low-average open-circuit voltages of 0.38 V and 0.14 V, respectively, along with a good Li/Na storage capacity of (223 mAhg−1) and a good cycling performance. Furthermore, there was a low diffusion barrier of 0.048 eV for Li0.0625V4C3 and 0.023 eV for Na0.0625V4C3, implying the prompt intercalation/extraction of Li/Na. Based on the findings of the current study, V4C3-based materials may be utilized as an anode for Li/Na-ion batteries in future applications. [ABSTRACT FROM AUTHOR]