Miracle-dz/UniFAR-FTUs huggingface dataset:
Development and testing of new exchange correlation functionals

in English Catalysts are used in 90% of the world’s chemical processes to produce 60% of its chemical products, and they are thus very important to our modern society. We therefore seek to better understand current catalytic materials, so that we can find alternatives that will improve the energy efficiency, selectivity or similar of current chemical processes, or to make new technologies economical feasible. Kohn-Sham density functional theory (KS-DFT) has proven to be a powerful theory to find trends in current catalytic materials, which can empower a more informed search for better alternatives. KS-DFT relies on accurate and efficient approximations to the exchange correlation functional, yet these functional approximations have lacked a systematic way to estimate the underlying uncertainties. A Bayesian error estimation approach provides a mechanism for calculating approximative uncertainties, and so accurate, computationally feasible exchange-correlation approximations that incorporate it have been called for. This thesis presents significant steps forwards towards providing general applicable exchange-correlation functional approximations with Bayesian error estimation capabilities. A semi-empirical approach was used with a machine learning toolset to improve accuracy and transferability of the functional approximations. The toolset includes Tikhonov regularization of smoothness in a transformed model space, for ensuring sensible model solutions; an explicit model compromise with a geometric mean loss function, for ensuring generally applicable models; a robust MM-estimator loss function, for ensuring resistance to outliers in data; and a hierarchical bootstrap resampling estimating prediction error validation method, for selecting the model complexity that provide best transferability outside the training data. Three new semi-empirical functional approximations have been made: BEEF-vdW, mBEEF, and mBEEFvdW. It is shown that these functionals are able balance the accuracy of predicting energetics of covalent and non-covalent chemistry better than any comparative functional that we have tested, and they could therefore become the functional approximations of choice for understanding chemical processes at the solid-gas and solid-liquid interfaces.
Kinetics of persistent photoconductivity in crystalline III–V semiconductors

Abstract Although persistent photocurrent (PPC) in photoconductive III–V semiconductors is known to be dominated by dispersive reaction kinetics, which produce a stretched exponential function decay, exp[−(t/τ)β], where τ is the effective reaction time and β (<1.0) is the dispersion parameter, the reason for the occurrence of the PPC is still not clear. Here, we discuss the origin of dispersive kinetic relaxation associated with a DX-like centre, i.e. deep levels associated with donors in III–V semiconductors. It is suggested that lattice relaxation of DX-like centres, accompanied by multi-phonon processes, may play a role in the dispersive nature of the PPC.
Understanding perovskite formation through the intramolecular exchange method in ambient conditions

Abstract. Among the methods to prepare hybrid organic–inorganic perovskite films, the intramolecular exchange method was the first one that made possible to prepare perovskite solar cells with efficiencies higher than 20%. However, perovskite formation by this method is not completely understood, especially in ambient conditions. In this work, perovskite films were prepared by the intramolecular exchange method in ambient conditions. The spin coating speed and the frequency of the MAI solution dripping onto PbI2(DMSO) were varied during the deposition steps. With the combination of these two parameters, a rigid control of the solvent drying was possible. Thus, depending on the chosen conditions, the intermediate (MA)2Pb3I8·2DMSO was formed with residual PbI2. Otherwise, direct formation of perovskite film was attained. A mechanism for the direct formation of bulk perovskite was proposed. We also investigated how the posterior thermal annealing affects the crystallinity and defects in perovskite films. With prolonged thermal annealing, the excess of MAI can be avoided, increasing the efficiency and decreasing the hysteresis of the solar cells. The best perovskite solar cell achieved a stabilized power output of 12.9%. The findings of this work pave the way for realizing the fabrication of efficient perovskite solar cells in ambient atmosphere, a very desirable condition for cost-efficient large scale manufacturing of this technology.
Biomimetic reduction of O2 in an acid medium on iron phthalocyanines axially coordinated to pyridine anchored on carbon nanotubes

An efficient and inexpensive catalyst for the oxygen reduction reaction (ORR) is the key missing component for large-scale development of fuel cells. Bio-inspired tethered electrocatalysts could be the solution to this problematic reaction. Either unsubstituted Fe phthalocyanine (FePc) or Fe hexadecachloro-phthalocyanine (16(Cl)FePc) was anchored to carbon nanotubes (CNTs) via a pyridine axial ligand. The results show that the fifth coordination plays a major role in increasing the catalytic activity of FePc and 16(Cl)FePc for the ORR. The coordination also allows the decoupling of the metal centre from the carbon support, thus changing the geometrical and electronic structure and hindering the production of H2O2. The pentacoordinated catalysts were stable in acidic pH according to the rotating disk analysis, but the activity of the hexadecachloro compound was not higher than that of the unsubstituted phthalocyanine. Cl atoms reduced the coupling between O2 and Fe, mismatching the energy of the frontier orbitals and lowering the activity towards the reduction of O2.
Reverse clustering: an outline for a concept and its use

ABSTRACT In this study, a new perspective on the application of the clustering approach is proposed. The perspective aims to identify the values of the parameters of clustering, including the choice of the algorithm itself, which lead to a possibly faithful rendering of a partition of data, which is known a priori. Motivation and possible interpretations are discussed which can be associated with such a reverse identification process. The essential motivation is associated, but not limited, to the primary objective of cluster analysis, i.e. gaining insight into the structure of the given data-set or family of data-sets. We propose to use evolutionary strategies for reverse analysis to be carried out in view of the characteristics of the problem considered. The concept and the feasibility of the proposed computational approach are illustrated by the analysis of an exemplary data-set. The preliminary results obtained are promising in both technical and cognitive terms.
Effect of Different Auxins Alone and Mixture of Benzene Aminopurine (BAP) and Kinetin (Kn) Along with Auxin 2,4-D on In Vitro Growth and Multiplication of Callus in B5 Medium Derived from Embryonic Cotyledon Excised Explants of Ashwagandha (Cultivated)

Ashwagandha (Withania somnifera) belongs to the member of family Solanaceae, having enormous aromatic properties and medicinal properties, has been included in an ancient (early) text of Ayurveda. It is very useful as an, contraceptive, amoebocide, bactericide, abortifacient, anodyne, and diuretic. But the risks of fungal infections are very high in these plants. Due to its over use this plants is going towards extinction so in vitro microprogation is a best method to protect this plant as well as to produced value added compounds in a very short time without any external environmental hazards. Higher percentage of in vitro morphogenic response was exhibited by explants mature embryo followed by explants mature cotyledon leaves. Half B5 medium (gamborg medium) with NAA, IBA, 2,4- Di-chlorophenyl acetic acid (2,4-D), BAP, Kinetin (Kn) and Sucrose (5% w/v) was employed either separately or in mixture. Cotyledonary leaves are generally produces callus in callus induction media and after several sub culturing its produces shoots and roots in shoot and root induction media. Regenerated plantlets were obtained successfully in the field after hardening. Mostly for in vitro organogenesis MS medium has been employed bus it has been also done in B5 medium with cotyledonary leave's explants of Withania somnifera.
Creating Binary Cu–Bi Compounds via High-Pressure Synthesis: A Combined Experimental and Theoretical Study

Exploration beyond the known phase space of thermodynamically stable compounds into the realm of metastable materials is a frontier of materials chemistry. The application of high pressure in experiment and theory provides a powerful vector by which to explore this uncharted phase space, allowing discovery of complex new structures and bonding in the solid state. We harnessed this approach for the Cu–Bi system, where the realization of new phases offers potential for exotic properties such as superconductivity. This potential is due to the presence of bismuth, which, by virtue of its status as one of the heaviest stable elements, forms a critical component in emergent materials such as superconductors and topological insulators. To fully investigate and understand the Cu–Bi system, we welded theoretical predictions with experiment to probe the Cu–Bi system under high pressures. By employing the powerful approach of in situ X-ray diffraction in a laser-heated diamond anvil cell (LHDAC), we thoroughly explo.
Effects of Rb Incorporation and Water Degradation on the Stability of the Cubic Formamidinium Lead Iodide Perovskite Surface: A First-Principles Study

Despite the major improvements in device efficiency, perovskite solar cells (PSCs) are limited by their poor stability due to the degradation toward moisture. Recently studies have demonstrated that the perovskite materials can be stabilized by adding more inorganic elements such as Cs and Rb. However, the specific mechanism is not yet fully established. In this paper, first-principles calculations were employed to investigate the effects of Rb incorporation and water degradation on cubic formamidinium lead iodide (FAPbI3) perovskite. The termination dependence of the structural stability of the representative (100), (010), and (001) surfaces was characterized by surface energies. The PbI2-terminated (001) surface was found to be the most stable surface structure. The Rb dopants were found to be energetically favorable, existing on the surface more than staying in the inner atomic layers. Furthermore, the degradation mechanism was investigated by water adsorption on the Rb-incorporated FAPbI3 (001) surfac.
C-Glycosylated cinnamoylfuran derivatives as novel anti-cancer agents

A series of C-glycosylated cinnamoylfuran derivatives were synthesized in excellent yield from free sugars. The C-glycosylated furan derivatives were prepared under aqueous reaction conditions. The anticancer potentials of the synthesized compounds were evaluated on the basis of their comparative cytotoxic effects on cancer cells (MCF-7 and HeLa) and normal cells (NKE). Among 28 compounds evaluated for their cytotoxic effects on cancer cells, three compounds (compounds 8, 24 and 28) were shown to have significant cytotoxic effects on MCF-7 and HeLa cell lines and comparatively less toxicity against normal NKE cell line. Based on its selectivity index, compound 24 was considered the most promising anticancer agent amongst the above three compounds. Further biochemical studies with compound 24 showed that both intrinsic and extrinsic pathways of apoptosis contribute to compound 24 mediated cytotoxicity.
Boron nitride nanotube-modified silicon oxycarbide ceramic composite: synthesis, characterization and applications in electrochemical energy storage

Polymer-derived ceramics (PDCs) such as silicon oxycarbide (SiOC) have shown promise as an electrode material for rechargeable Li-ion batteries (LIBs) owing to the synergy between its disordered carbon phase and hybrid bonds of silicon with oxygen and carbon. In addition to their unique structure, PDCs are known for their high surface area (~822.7 m g), which makes them potential candidates for supercapacitor applications. However, low electrical conductivity, voltage hysteresis, and first cycle lithium irreversibility have hindered their introduction into commercial devices. One approach to improving charge storage capacity is by interfacing the preceramic polymer with boron or aluminium prior pyrolysis. Recent research has shown that chemical interfacing with elemental boron, bulk boron powders and even exfoliated sheets of boron nitride leads to enhancements in thermal and electronic properties of the ceramic. This thesis reports the synthesis of a new type of PDC composite comprising of SiOC embedded with boron nitride nanotubes (BNNTs). This was achieved through the introduction of BNNT in SiOC pre-ceramic polymer at varying wt. % loading (0.25, 0.5 and 2.0 wt.%) followed by thermolysis at high temperature. Electron microscopy and a range of spectroscopy techniques were employed to confirm the polymer-to-ceramic transformation and presence of disordered carbon phase. Transmission electron microscopy confirmed the tubular morphology of BNNT in the composite. To test the material for electrochemical applications, the powders were then made into free-standing paper-like electrodes with reduced graphene oxide (rGO) acting as support material. The synthesized free-standing electrodes were characterized and tested as electrochemical energy storage materials for LIBs and symmetric supercapacitor applications. Among the SiOCBNNT composite paper tested as anode materials for LIBs, the 0.25 wt. % BNNT composite paper demonstrated the highest first cycle lithiation capacity corresponding to 812 mAh g (at a current density of 100 mA g) with a stable charge capacity of 238 mAh g when asymmetrically cycled after 25 cycles. On the contrary, the 0.5 wt. % BNNT composite paper demonstrated the highest specific capacitance corresponding to 78.93 F g at a current density of 1 A g and a cyclic retention of 86% after 185 cycles. This study shows that the free carbon content of SiOC-BNNT ceramic composite can be rationally modified by varying the wt. % of BNNT. As such, the paper composite can be used as an electrode material for electrochemical energy storage.
Physicochemical and ion exchange studies of resin derived from phydroxybenzoicacidand ethylenediamine with formaldehyde

A number of resins have been synthesized by reacting p-hydroxybenzoic acid with diamines and formaldehyde in presence of 2M HCl as catalyst, proved to be selective chelating ion-exchange resins for certain metals. The present paper reports the synthesis, characterization and ion exchange properties of a pHEF terpolymer. Chelation ion exchange properties have also been studied for Fe3+, Cu2+, Ni 2+, Co2+, Zn2+, Cd2+, Pb2+ ions employing a batch equilibrium method. It was employed to study the selectivity of metal ion uptake involving the measurements of distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over wide pH range and in a media of various ionic strengths. The terpolymer showed higher selectivity for Fe3+, Cu2+ and Ni 2+ions than for Co2+, Zn2+, Cd2+, and Pb2+ ions. The resin pHEF was synthesized by the condensation of p-hydroxybenzoic acid and ethylenediamine with formaldehyde in the presence of a hydrochloric acid catalyst. Terpolymer was characterized by elemental analysis, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and UV- Visible spectral studies. The number average
Kinetic study of nickel laterite reduction roasting by palm kernel shell charcoal

Demand to process nickel-bearing laterite ore increase as continuous depletion of high-grade nickel-bearing sulfide ore takes place. Due to its common nickel association with iron, processing nickel laterite ore into nickel pig iron (NPI) has been developed by some industries. However, to achieve satisfying nickel recoveries, the process needs massive high-grade metallurgical coke consumption. Concerning on the sustainability of coke supply and positive carbon emission, reduction of nickel laterite ore using biomass-based reductor was being studied.In this study, saprolitic nickel laterite ore was being reduced by palm kernel shell charcoal at several temperatures (800–1000 °C). Variation of biomass-laterite composition was also conducted to study the reduction mechanism. X-ray diffraction and gravimetry analysis were applied to justify the phenomenon and predict kinetic model of the reduction. Results of this study provide information that palm kernel shell charcoal has similar reducing result compared with the conventional method. Reduction, however, was carried out by carbon monoxide rather than solid carbon. Regarding kinetics, Ginstling-Brouhnstein kinetic model provides satisfying results to predict the reduction phenomenon.
Conducting Polymer/SWCNTs Modular Hybrid Materials via Diels–Alder Ligation

The development of a facile covalent strategy for the fabrication of organic conducting polymers (OCPs)/carbon nanotubes (CNTs) based molecular hybrid materials remains a challenge and is expected to address the detrimental intrinsic bundling issue of CNTs. In view of the pristine CNTs’ ability to undergo Diels–Alder reactions with dienes, we report the synthesis of a novel poly(3-hexylthiophene) (P3HT) based organic conducting polymer (OCP) with terminal cyclopentadienyl (Cp) groups. The synthetic strategy employed is based on a combination of in situ end group functionalization via Grignard metathesis (GRIM) polymerization and a subsequent end group switching via reaction with nickelocene. Characterization data from Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI–TOF MS) fully support the successful synthesis of monofunctional Cp-capped P3HT, which was found to be highly reactive toward dienophile end-capped polystyrene (PS). The Cp-capped P3HT was subsequently ligate.
Thermal Performances of a Small-Scale Regenerative Combustion Chamber for Ultra-Micro Gas Turbine

ABSTRACT New manufacturing techniques and technologies have led to the development of a new research topic focusing on fluid dynamics and combustion at small scale, in particular in the last 20 years. One of the most promising technologies is represented by the ultra-micro gas turbines, which were developed with the aim of providing a portable and clean power source for devices, such as unmanned aerial vehicles and drones, global positioning system, exoskeletons for military applications, and backup emergency power supply. Currently, not many prototypes have been built because of the issues posed by scaling down the system. Among these there are excessive fluid dynamic and thermal losses decreasing the overall efficiency, elevated combined thermal and mechanical stress of components, and the necessity of developing high speed bearings. This study focuses on investigating experimentally a possible solution to effectively recover heat contained in the combustion products to preheat the unburned mixture, increasing the overall efficiency. Thus, an 18-mm internal-diameter regenerative combustion chamber surrounded by two sets of helicoidal channels was developed. The combustion chamber included a sintered steel porous medium to allow the flame to stabilize. The combustion products were recirculated in order to maximize the heat transferred to the cold mixture, with benefits in terms of flammability limits and fuel consumption. Mass flow rate and equivalence ratio were varied in the tests and the gas temperatures at different locations within the combustion chamber were measured, along with the composition of the combustion products. The heat released was included in the range 65 W and 343 W. Tests were run in both a non-insulated and insulated configuration and comparisons were made. Resulted showed the achievement of clean combustion of liquefied petroleum gas with combustion efficiency higher than 99% for lean mixtures. Also, a good level of heat recovery was achieved, reaching 45% and 23% of heat transferred to the reactants from the exhaust gases in the insulated and non-insulated combustion chamber, respectively.
Synthesis of anti-inflammatory 2,3-unsaturated O-glycosides using conventional and microwave heating techniques

Abstract The preparation of eight 2,3-unsaturated O-glycosides from D-glycals and alcohols, using montmorillonite K-10 as an acid catalyst, is described. The Ferrier rearrangement products were obtained in good yields using conventional heating and microwave irradiation but the reaction time was substantially reduced employing the latter procedure. The yields were slightly lower under microwave exposure. Five of the di-O-acetylated products were deacetylated to the glycosides in excellent yields. The acetylated products possess good anti-inflammatory property suggesting that the acetyl group plays an important role in reducing the inflammation. Among the compounds tested, glycosides containing thiophene as an aglycone present much better inflammation reducing characteristics than the analogues without this function.
IN VITRO ANTIOXIDANT ACTIVITY OF BARK EXTRACTS OF OROXYLUM INDICUM (L) VENT

Objectives: The aim of the present work is to screen the antioxidant potentiality of the bark extract of Oroxylum indicum (L) Vent, ethnomedicinally prescribed plant as hepatoprotective. Methods: Bark extracts were prepared using soxhlet apparatus. Total phenol, flavonoid, and total alkaloid were analyzed using Folin–Ciocalteu assay, aluminum chloride colorimetric assay, atropine standard, respectively. Antioxidant capacity and free radical scavenging potentialities were done by several in vitro methods, viz . ; 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide scavenging activity, reducing power assay, metal chelating activity, ferric reducing ability of plasma (FRAP) assay, and thiobarbituric acid (TBA) method. Result: Total phenol, flavonoid, and alkaloid were found to be highest in methanolic extract of O. indicum (L) Vent. Methanolic extract of the bark showed very low inhibitory concentration (IC50) and effective concentration values for DPPH assay and reducing power assay compared to another extract. In hydrogen peroxide scavenging activity assay, the lowest IC50 value was recorded in methanolic extract with 153.45±0.06 μg/ml. The FRAP assay for O. indicum methanolic extract showed the highest activity at 940.09±0.07 μg/mL of ascorbic acid equivalent. The ferric reducing capacity and TBA values of the plant extracts confirmed the presence antioxidant principles in the bark of the said plant. Conclusion: These underused plants may be used for mitigating the detrimental effect of oxidative stress and reactive oxygen species-mediated disease and thus justifies its use in folklore medicines.