Abstract: In the process of acidizing operation, especially in ultra-high temperature wells, metal components such as wellbore tubing and surface equipment are severely corroded by acid fluids, leading to operational challenges in oilfield production. At present, the ad-dition of corrosion inhibitors is one of the most effective methods to mitigate metal corrosion. Pyridine residues, quinoline quaternary ammonium salts, aldehyde ketone amine condensates, acetylenic methyl ammonia and imidazoline corrosion inhibitors have been widely studied in the industry. Among them quaternary ammonium salts are widely used in oilfield production due to their excellent corrosion resistance, low toxicity and good water solubility. However, their limited heat resistance makes them unsuitable for ultra-deep exploration wells or scientific research wells. This study fo-cuses on N-heterocyclic quaternary ammonium salt-based corrosion inhibitors (alkyl quinolinium quaternary ammonium salts), which can withstand temperatures up to 200°C, meeting the requirements of ultra-high temperature wells.

Abstract:

The 1,3 -dipolar cycloaddition reaction of nitrile oxides, prepared in situ from pyridine aldehyde oximes, with propargyloxy- or propargylaminocoumarins afforded the corresponding new 3,5-disubstituted isoxazoles in moderate to good yields. As oxidants for the formation of nitrile oxides utilized (diacetoxyiodo)benzene (PIDA) at room temperature or under microwave irradiation or tert-butyl nitrite (TBN) under reflux. Preliminary in vitro screening tests for some biological activities of the new compounds have been performed. Compounds 12b and 13a are potent LOX inhibitors with IC₅₀ 5 μΜ and 10 μΜ, respectively, while hybrids 12b and 13a exhibit moderate to low anticancer activities on Hela, HT-29, and H1437 cancer cells.

Abstract:

Self-cleaning solar mirrors coatings are targeted at reducing the amount of cleaning water, saving on the costs of solar fields ordinary maintenance and therefore on costs of electricity produced with concentrated solar technology. Different approaches have been tailored for mirrors of BSM and FSM architectures, having in common that the self-cleaning coating is the last layer exposed to fouling, a sort of solar mirror “skin”. The most recent trend in this sector is to give this skin sensing properties, so that it can self-diagnose its performance in terms of soiling and/or failure toward the ambitious goal of solar field and CSP digitalization. Starting from the previous results about auxetic aluminum nitrides and ZnO transparent composites developed for substituting alumina as BSM self-cleaning skin, here it has been explored the possibility of conferring sensing properties to this skin, by means of utilizing their piezoelectric properties, that can be correlated to dust dep-osition and hence to the soiling of the surface, and/or electrical their resistive behavior that can be useful for monitoring failure event. Good d33 values obtained for the sputtered piezoelectric AlN and tailored electrical properties of ZnO composites, combined to self-cleaning effect and optical clarity in the full solar range, enable the utilization of produced coatings as potential self-aware solar mirrors skin.

Abstract: Incorporation of enzyme immobilized ZnO nanoparticles in to hydrophilic polymer Polymethyl metharcylate (PMMA) has been considered in this present study with the goal of developing antimicrobial hydrophobic textile coatings. The enzyme immobilized nanoparticles polymer coatings on textiles by dip coating, using the polymer Polymethyl methacrylate and proteolytic enzymes alpha chymotripsin immobilized green synthesized, amino functionalized ZnO nanoparticles. Immobilization of enzymes on nanoparticles with large surface to volume ratio provides obvious advantage. Alpha chymotripsin was immobilized on amino functionalized ZnO nanoparticles dispersed in n-proponal. The enzyme immobilized ZnO nanoparticles were used for making the ZnO/PMMA polymer nanocomposite coating. This coating was applied on cotton textile by dip coating and the coated textiles were evaluated for antimicrobial and hydrophobicity Properties.

Abstract: Carbon dots (CDs) are metal-free carbon-based nanoparticles. They possess excellent photoluminescent properties, various physical properties, good chemical stability, high water solubility, high biocompatibility, and tunable surface functionalities, suitable for biomedical applications. Their properties are subject to synthetic conditions such as pH, reaction time, temperature, precursor, and solvent. Until now a large amount of articles on synthesis and biomedical applications of CDs using their photoluminescent properties have been reported. However, their researches on magnetic properties and especially, diamagnetic chemical exchange saturation transfer (diaCEST) in magnetic resonance imaging (MRI) are very poor. The diaCEST MRI contrast agents are based on exchangeable protons of materials with bulk water protons and thus, different from conventional MRI contrast agents which are based on enhancements of proton spin relaxations of bulk water and tissue. In this review, various syntheses, characterizations, magnetic properties, and potential applications of CDs as diaCEST MRI contrast agents are reviewed. Finally, future perspectives of CDs as the next generation diaCEST MRI contrast agents are discussed.

Abstract: In this article, nanopowder zinc sulfide (ZnS) was chemically precipitated starting from Zn powder and diluted HCl to make a ZnCl2 solution followed by a reduction process using a laboratory-prepared Na2S. Na2S was produced by dissolving NaOH in distilled water. Then, according to the stochiometric values of the compound, high-purity S powder was added while heating and stirring the mixture to a temperature of approximately 105 oC. The mixture was finally dried under a vacuum at 200 oC. The produced ZnS was studied using SEM coupled with EDS, XRD analysis, UV-Vis, and FTIR techniques. The results confirmed the synthesis of nanoscale ZnS powder and its chemical composition. To prepare ZnS pellets, the ZnS nanopowder was compacted and sintered under an Argon atmosphere at 400°C for 8 hours. The SEM and EDS examined the microscopic structure of the sintered pellets. The sintered ZnS pellets were also used as an evaporation source for thin deposition via E-beam evaporation. Furthermore, the optical properties of the deposited thin films were studied using UV-Visible spectroscopy in the wavelength range of 190 -1100 nm, where the energy gaps (Eg) were calculated for thin films with thicknesses of 111 nm and 40 nm, and they were around 4.72 eV and 5.82 eV, respectively. This article offers a facile production route of a high-purity ZnS nanopowder and its application as an evaporation source for the E-beam deposition of ZnS thin films.

Abstract: In this study, we designed and fabricated a lightweight and high-precision K-band corrugated horn antenna with a wide operating frequency using chemical silver plating and three-dimensional (3D) printing technology. The corrugated horn antenna was mainly made of polymer materials, with a metal silver coating on the inner surface, and its mass was only 17% of that of a steel corrugated horn antenna. 3D printing technology achieved the integrated solidification and molding of the complex internal structure of the K-band corrugated horn antenna. The antenna had a return loss mostly below −20 dB in the range of 18.0–27.0 GHz and a gain of over 14 dB in the range of 18.0–24.0 GHz. The measured results of the directional pattern agreed well with the simulation results. This technology is expected to bring revolutionary changes to the overall design and manufacturing process of small satellites and radar systems.

Abstract:

The Selective Catalytic Oxidation of ammonia (NH₃-SCO) is gaining attention due to the hazardous nature of NH₃ and its inclusion in emission reduction frameworks such as the National Emission Ceilings Directive and the Gothenburg Protocol (1999). Copper-based hydroxyapatite (Cu/HAP) catalysts have emerged as a promising solution, offering high activity and cost-effectiveness.This study evaluates two preparation methods: a one-pot co-precipitation technique and post-synthesis copper deposition, varying contact time and copper concentration. The influence of copper loading and preparation method on catalyst performance in NH₃-SCO was investigated in a continuous flow reactor over a temperature range of 200–500°C, with a fixed gas hourly space velocity (GHSV) of 120,000 h⁻¹ and an NH₃/O₂ ratio of 0.03.X-ray diffraction and DR-UV spectroscopy confirmed the high crystallinity of HAP and provided insights into copper speciation. X-ray photoelectron spectroscopy revealed that Cu/HAP catalysts prepared via one-pot co-precipitation predominantly contained isolated Cu²⁺ species, which were associated with high catalytic activity in selective NH₃-SCO. Conversely, a higher degree of copper structuring was observed in catalysts prepared by post-synthesis deposition, particularly at higher Cu loadings.These findings highlight the potential to tailor Cu structuring on HAP to enhance performance in NH₃-SCO through optimized preparation strategies.

Abstract: Autonomous vehicles (AVs) represent a transformative advancement in transportation, with object detection serving as a critical component for their safe and efficient operation. This paper provides a thorough analysis of object detection techniques tailored for autonomous vehicles, encompassing traditional methods, deep learning-based approaches, and emerging trends. We begin by examining classical techniques such as Haar cascades and Histogram of Oriented Gradients (HOG), highlighting their limitations in handling complex real-world scenarios. Subsequently, we delve into state-of-the-art deep learning models, including Convolutional Neural Networks (CNNs), Region-based CNNs (R-CNNs), You Only Look Once (YOLO), and Single Shot Detectors (SSDs), evaluating their accuracy, speed, and robustness in diverse driving conditions. The study also explores the integration of sensor fusion techniques, combining data from cameras, LiDAR, and radar to enhance detection reliability. Challenges such as occlusions, adverse weather, and real-time processing constraints are discussed, along with potential solutions. Furthermore, we analyze the impact of dataset quality, annotation methods, and evaluation metrics on model performance. Finally, the paper outlines future directions, including the adoption of transformer-based architectures, edge computing, and continual learning for improved adaptability. This comprehensive review aims to guide researchers and practitioners in selecting and advancing object detection methodologies to meet the evolving demands of autonomous driving systems.

Abstract: Nickel-doped Fe3O4/graphene oxide powders were synthesized by the co-precipitation method varying the Ni/Fe ratio, and the activity of the materials towards the oxygen reduction reaction in a microbial fuel cell (MFC) was studied. The samples presented X-ray diffraction peaks associated with magnetite, maghemite and Ni ferrite, as well as evidence of Fe2O3. Scanning electron micrographs showed exfoliated sheet decorated with nanoparticles and transmission electron micrographs showed spherical nanoparticles about 10 nm diameter well distributed onto the individual graphene sheet. The electrocatalytic activity for the oxygen reduction reaction (ORR) was studied by cyclic voltammetry in an air saturated electrolyte, finding that the best catalyst was the sample with a 1:2 Ni/Fe ratio, using a catalyst concentration of 15 mg/cm2 onto a graphite felt. The 1:2 Ni/Fe catalyst provided an oxygen reduction potential of 397 mV and a maximum oxygen reduction current of -0.13 mA; for comparison, an electrode prepared with GO/Fe3O4 showed a maximum ORR of 369 mV and a maximum current of -0.03 mA. The MFC’s with vertical proton membrane were prepared with Ni-doped Fe3O4 and Fe3O4/graphene oxide and tested for 24 h; reached a stable OCV of +400 mV and +300 mV OCV, respectively.

Abstract: Purity determination of precious metal is very crucial due to the economic value and hence metals like gold used for making jewelry must reflect the true value. Quantitative determination of jewelry is very important to ensure product integrity and consumer protection. The aim of the current study is to assess and compare the performance of EDXRF technique in the quality determination of gold jewelry. A total of 119 jewelry items containing gold of varying purity were assessed in the study and compared with fire assay. In conclusion, EDXRF technique appears to be a comparable alternative for rapid determination of elemental composition of gold in alloys especially for finished and semifinished ornaments. Further refinements in analytical accuracy may even replace destructive methods in practice.

Abstract:

Currently in order to calculate the number of covalent bonds for cyclic unsaturated organic molecules there are equations that include the index of hydrogen deficiency (IHD), a σ-bonds derivation from the Euler characteristic for planar graphs and other empirical formulations. However the IHD which is also known as the degree of unsaturation (DOU) requires to assign a numerical value for the pi(π) bonds and rings without knowing their precise number in a molecule, and all the other equations that are used to determine the numerical value of sigma(σ) and single bonds are made up of variables such as the number of rings, double and triple bonds. In this manuscript we present a novel type of mathematical model that was deduced by using chemical graph theory and can be applied to calculate the value of covalent bonds and rings for cyclic organic molecules with double or triple bonds only knowing the number of atoms, their corresponding valences and a new chemical concept which we called total unsaturation (TU) that represents the degree of unsaturation expressed as a percentage. The objective of this study is to highlight a deeper mathematical relationship formed by multiple structural elements of a molecule in order to enhance the correlations between graph theory and organic chemistry from a different perspective that is primarly focused on the number of bonds.

Abstract:

Fluorescent chemosensors are increasingly becoming relevant in recognition chemistry due to their sensitivity, selectivity, fast response time, real-time detection capability, and low cost. Boronic acids have been reported for the recognition of mycolactone, the cytotoxin responsible for tissue damage in Buruli ulcer disease. A library of fluorescent arylboronic acid chemosensors with various signaling moieties with certain beneficial photophysical characteristics (i.e. aminoacridine, aminoquinoline, azo, BODIPY, coumarin, fluorescein, and rhodamine variants); and a recognition moiety (i.e. boronic acid unit) were rationally designed and synthesized using combinatorial approaches; purified and fully characterized using a set of complementary spectrometric and spectroscopic techniques such as NMR, LC-MS, FT-IR, and X-ray crystallography. In addition, a complete set of basic photophysical quantities such as absorption maxima (l_abs^max), emission maxima (l_em^max), Stokes shift (∆λ), molar extinction coefficient (ε), fluorescence quantum yield (Φ_F), and brightness were determined using UV-vis absorption and fluorescence emission spectroscopy techniques. The synthesized arylboronic acid chemosensors were investigated as chemosensors for mycolactone detection using the fluorescent-thin layer chromatography (f-TLC) method. Compound 7 (with a coumarin core) emerged the best (l_abs^max = 456 nm, (l_em^max = 590 nm, ∆λ = 134 nm, ε = 52816 M^-1cm^-1, Φ_F = 0.78, and brightness = 41197 M^-1cm^-1).

Abstract: With the advancement of new synthetic techniques, 5-Methyl-2-ethylfuran (5-MEF) has emerged as a promising renewable biofuel. In this study, the potential energy surfaces for the unimolecular dissociation reaction, H-addition reaction, and H-abstraction reaction of 5-MEF were mapped at the CBS-QB3 level. The temperature- and pressure-dependent rate constants for these reactions on the potential energy surfaces were determined by solving the master equation, using both transition state theory and Rice-Ramsperger-Kassel-Marcus theory. The results showed that the dissociation reaction of the C(6) site on the branched chain of 5-MEF has the largest rate constant and is the main decomposition pathway, while the dissociation reaction of the H atom on the furan ring has a lower rate constant and is not the main reaction pathway. In addition, the dissociation of H atoms on the branched chain and intramolecular H-transfer reactions also have high-rate constants and play an important role in the decomposition of 5-MEF. H-addition reactions mainly occur at the C(2) and C(5) sites, and the generation of the corresponding products through β-breakage becomes the main reaction pathway. With the increase of temperature, the H-addition reaction at the C(2) site gradually changes to a substitution reaction, dominating the formation of C₂H₅ and 2-methylfuran.

Abstract: Periodically modulated optical coatings, fabricated by depositing conformal films on modulated substrates, offer unique capabilities for spectral and spatial filtering of light. However, conventional deposition methods often do not achieve the required replication and conformality on submicron-size structured surfaces. In this paper, we compare various thin film deposition techniques, including electron beam evaporation, atomic layer deposition, and ion beam sputtering, to evaluate their ability to control multilayer coating growth on periodically modulated substrates. Our study demonstrates that both single-layer and multilayer coatings produced by ion beam sputtering effectively replicate the initial geometry of structured surfaces, thereby enhancing optical performance.

Abstract: The recent fast advances in consumer electronics, especially in cell phones and displays, have led to the development of ultrathin, hence flexible, glasses. Once available, such flexible glasses have proven to be of great interest and usefulness in other fields, too. Flexible photonics, for instance, has quickly taken advantage of this new material. At first sight, “flexible glass” appears to be an oxymoron. Glass is, by definition, fragile and highly breakable: its structure has puzzled scientists for decades, but it is evident that in most conditions it is a rigid material, so how can it bend? This possibility, however, has aroused the interest of artists and craftsmen since ancient times: thus, in Roman times the myth of flexible glass was born. Furthermore, the myth appeared again in the Middle Age, connected to a religious miracle. Today, however, flexible glass is no more a myth but a reality, due to the fact that current technology permits to produce micron-thick glass sheets, and any ultrathin material can be bent. Flexibility is coming from the present capability to manufacture glass sheet at a tens of microns thickness coupled with the development of strengthening methods; it is also worth highlighting that, at nanometric scale, silicate glass presents plastic behavior. The most significant application area of flexible glass is consumer electronics, for the displays of smartphones and tablets, and for wearables, where flexibility and durability are crucial. Automotive and medical sectors are also gaining importance. A very relevant field, both for the market and the technological progress, is solar photovoltaics; mechanical flexibility and lightweight have allowed solar cells to evolve toward devices that possess the advantages of conformability, bendability, wearability, and moldability. The mature roll-to-roll manufacturing technology also permits to achieve high-performance devices at low cost. Here, a brief overview of the history of flexible glass and some examples of its application in solar photovoltaics are presented.

Abstract: A series of new 3-alkyl substituted cis- and trans-(±)-3,4-dihydro-6,7-dimethoxy-1-oxo-1H-isochromene-4-carboxylic acids (cis-/trans-1-3) was synthesized through the reaction of 6,7-dimethoxyhomophthalic anhydride with aliphatic aldehydes of varying chain lengths. Their structure and configuration were elucidated using spectral methods, including 1H-, 13C-, DEPT-135-NMR, and HRMS analyses. A deductive conformational analysis was performed for determining the preferred conformations in solution and to explain the observed vicinal coupling constants.

Abstract: To investigate the specific performance enhancement of oilfield surfactants by using sodium p-aminobenzenesulfonate as a connecting group, cationic surfactant N,N-dimethyl-N-(oxiran-2-ylmethyl)dodecan-1-aminium (DDPA) and zwitterionic gemini surfactant 4-[bis(3-(dodecyldimethylamino)-2-hydroxypropyl)amino]benzenesulfonate sodium (DDBS) were synthesized. The oil recovery performance of these surfactants was compared, revealing that DDBS outperforms DDPA in thermal stability, wettability, adsorption, and resistance to temperature and salinity variations, as well as surface/interface activity, except for emulsification. Core flooding experiments, simulating the conditions of the Xinjiang oilfield, demonstrated that DDBS can achieve the same enhanced oil recovery effect at a concentration that is 1/15 of that of DDPA. DDBS and DDPA can incrementally improve recovery rates by 7.9% and 8.5%. Furthermore, the synergistic formulation of DDBS with sodium dodecylbenzenesulfonate (SDS) significantly optimized performance, achieving a reduction in interfacial tension to 0.0301 mN m^(-1). This study provides a research and data foundation for the application of new surfactants in petroleum extraction.

Abstract: Solid waste treatment and resourceization critically depend on waste characterization. Heavy metals and critical raw materials are found as trace elements in solid waste dumps. Their reliable quantification plays a critical role for decision risk regarding effective waste management. Reliable quantification of trace elements is a very difficult issue. Hence, the paper addresses a new conservative approach for data analysis in screening for trace element in waste dumps. We propose a theoretical model for statistical data interpretation to overcome the drawbacks of the conventional approaches that are based on unproved hypotheses, like binomial, Poisson or Gaussian distributions of the particles carrying the analyte. Our model addresses concentration values close to the limit of quantification (LOQ) of an analytical method. The model fills the gap of data analysis in case where a set of laboratory outcomes are uniform distributed. Our approach cope with results reported as lower than LOQ. The model was applied on XRFS results carried on tailings to emphasize the differences among classic, robust and conservative data analyses. Classical analyses overestimate the concentration values and sub-evaluate the associated uncertainties which enhances the decision risk. The paper demonstrates that conservative approach is mandatory in case of screening for trace elements if concentration values are uniform distributed. The model can be applied to any solid waste dump, regardless the analytical method used for trace element screening.

Abstract: Oxovanadium and zinc complexes are reported as insulin-mimetics. They inhibit several proteins including enzymes which belong to the same class of membrane sensitive phosphatases, similar in terms of general architecture and biochemistry of the active site. Borrowing from this summary, we explore the structural and electronic properties of representative oxovanadium and zinc complexes as computed in isolation and upon binding to PTEN and PTP1B phosphatases. Using crystallographic data and quantum chemistry calculations, we investigate how bonding nature and structural flexibility of the studied inhibitors affects efficiency of their binding to the active sites of the enzymes: albeit different, the two active sites represent evolutionary variant choices of the same type of biochemistry of phosphatases. As a result of our studies, we address optical responses which can be suitable for diagnostics and discuss engineering of AI assisted protein embedding to alter electronic states of metal centres which may be beneficial for biomedical and quantum information applications within the bio-spintronics of tomorrow.