bluuebunny/crossref_metadata_2025 huggingface dataset:
Construction of PROTAC-Mediated Ternary Complex Structure Distribution Profiles Using Extensive Conformational Search
Authors: Kudo Genki , Hirao Takumi , Harada Ryuhei , Shigeta Yasuteru , Hirokawa Takatsugu , Yoshino Ryunosuke
Published: April 2024

Proteolysis-targeting chimeras (PROTACs) are heterobifunctional small molecules that recruit E3 ubiquitin ligases to a target protein and induce its ubiquitination by forming a ternary complex. For rational PROTAC design, computational methods that provide molecular insights into these association structures are required. In this study, we attempted extensive conformational search of PROTAC-mediated ternary complex structures using enhanced conformational sampling methods. Stable conformations were extracted from the molecular dynamics’ ensembles by constructing Markov state models as their distribution profiles. These insights provided rational structure–activity relationships for PROTACs through the protein-ligand interaction analysis and the modeling of the ubiquitination system.
Predicting Colloidal Interaction Parameters from Small Angle X-Ray Scattering Curves using Artificial Neural Networks and Markov Chain Monte Carlo Sampling
Authors: Wong Kelvin , Runzhang Qi , Ye Yang , Zhi Luo , Guldin Stefan , Butler Keith
Published: April 2024

Small Angle X-Ray Scattering (SAXS) is a characterization technique which allows for the study of colloidal interactions by fitting the structure factor of the SAXS profile for a selected model and closure relation. However, the applicability of this approach is constrained by the limited number of existing models which can be fitted analytically, as well as the narrow operating range for which the models are valid. In this work, we demonstrate a proof-of-concept for using an artificial neural network (ANN) trained on small-angle x-ray scattering (SAXS) curves obtained from Monte Carlo (MC) simulations to predict values of the effective macroion valency (Zeff) and the Debye length (κ) for a given SAXS profile. This ANN, which was trained on 200,000 simulated SAXS curves, was able to predict values of Zeff and κ for a test set containing 25,000 simulated SAXS curves with ±20% accuracy to the ground truth values. Subsequently, an ANN was used as a surrogate model in a Markov Chain Monte Carlo sampling algorithm to obtain maximum a posteriori (MAP), associated confidence intervals estimates and details of correlations of Zeff and κ for an experimentally obtained SAXS profile.
Illuminating Anions in Biology with Genetically Encoded Fluorescent Biosensors
Authors: Cook Mariah , Phelps Shelby , Tutol Jasmine , Adams Derik , Dodani Sheel
Published: April 2024

Anions are critical to all life forms. Anions can be absorbed as nutrients or biosynthesized. Anions shape a spectrum of fundamental biological processes at the organismal, cellular, and subcellular scales. Genetically encoded fluorescent biosensors can capture anions in action across time and space dimensions with microscopy. The firsts of such technologies were reported more than 20 years ago for monoatomic chloride and polyatomic cAMP anions. However, the recent boom of anion biosensors illuminates the unknowns and opportunities that remain for toolmakers and end users to meet across the aisle to spur innovations in biosensor designs and applications for discovery anion biology. In a first-of-its-kind review, we will canvas progress made over the last three years for biologically relevant anions that can be classified as halides, oxyanions, carboxylates, and nucleotides.
Concepciones acerca de la enseñanza en docentes de Ingeniería: diseño y validación de un cuestionario de dilemas y estudio descriptivo
Authors: Buffa Fabián Alejandro , García María Basilisa , Moro Lucrecia Ethel , Menna Maximo , Massa Paola Andrea , Fanovich María Alejandra , Fuchs Vanesa Mabel
Published: April 2024

El presente trabajo consiste en el diseño y validación de un cuestionario de dilemas elaborado para indagar concepciones sobre la enseñanza en docentes de ingeniería. El marco teórico desde el cual fueron interpretadas las concepciones es el de las teorías implícitas, asumiendo que son representaciones que, si bien están explícitamente constituidas en la memoria cognitiva, poseen cierto carácter implícito desde la posibilidad que tiene el sujeto de hacerlas conscientes y verbalizarlas. La versión final del cuestionario consiste en doce dilemas que abarcan aspectos vinculados con “qué” y con “cómo” se enseña. Cada dilema tiene tres opciones de respuesta, correspondiendo cada una con las tres concepciones sobre la enseñanza obtenidas en un estudio previo de carácter cualitativo. La versión final del instrumento mostró un grado de fiabilidad aceptable (Alfa de Cronbach = 0,702). La prueba piloto aplicada a una muestra de 100 docentes de la Facultad de Ingeniería de la Universidad Nacional de Mar del Plata mostró que este instrumento es útil para describir sus concepciones sobre la enseñanza.
Retos y oportunidades para una evaluación cualitativa, bidimensional y por competencias de ingeniería
Authors: Merchán Rubiano Sandra Milena , Rodriguez-Rico Hernando
Published: April 2024

La evaluación por competencias es un campo de estudio con amplia producción sobre estándares, marcos de referencia e implementaciones tecnológicas en distintas áreas disciplinares, que se valoran mayoritariamente desde la perspectiva metodológica. No obstante, se encuentran pocas contribuciones que permiten valorar los potenciales y desafíos que implican su implementación a la luz de los factores socioculturales involucrados (las creencias, los valores, las comprensiones); entendiéndose las prácticas de evaluación como acciones que configuran el hecho social de la educación. El trabajo que se presenta reflexiona sobre algunos de estos aspectos a partir de indagar a una muestra de actores del proceso evaluativo en el Programa de Ingeniería de Sistemas de la Universidad El Bosque, con el fin de valorar la práctica actual de evaluación de aprendizajes, y de reconocer los retos y oportunidades que deben tenerse en cuenta para la implementación de un sistema de evaluación por competencias.
Desarrollo de la metodología de aprendizaje basado en problemas en un curso de ingeniería
Authors: Rodríguez Ruth , Angulo Sánchez Lilliam , Leitón Sancho Natalie
Published: April 2024

Las carreras universitarias relacionadas con temas de ciencia, tecnología, ingeniería y matemáticas están experimentando más que nunca con nuevas metodologías para impartir clases. Aunque la Metodología Basada en Problemas (PBL por sus siglas en inglés) no es nueva, muchas universidades aún no han desarrollado procedimientos específicos que se ajusten al contenido de sus cursos. Este informe detalla la metodología experimental que se pretende aplicar en el curso de Probabilidad y Estadística Descriptiva. Curso que es común para todas las carreras de ingeniería en una universidad privada en Costa Rica. En esta primera etapa, se encuentra que alrededor del 50% de los estudiantes apoyan la metodología y la recomiendan para otros cursos. En el corto tiempo de aplicación de la metodología, no hay diferencias significativas en el rendimiento académico de los estudiantes, sin embargo, la información recopilada es el insumo principal para el desarrollo de nuevos programas y procesos de capacitación de docentes en la metodología PBL.
Análisis descriptivo de los factores de impacto en las pruebas Saber Pro de estudiantes de Ingeniería Electrónica
Authors: Castro Casadiego Sergio , Guevara Ibarra Dinael , Acevedo Jaimes Leidy Julieth , Medina Delgado Byron
Published: April 2024

En este documento se presentan y analizan los resultados obtenidos al aplicar un instrumento de recolección de información a estudiantes de ingeniería electrónica de la Universidad Francisco de Paula Santander, con el fin de determinar los factores de impacto en las pruebas Saber Pro.  En su mayoría, las opciones de respuesta se encontraron en escala de Likert y se indagó respecto al nivel aptitudinal de los estudiantes, su preparación para las pruebas y el nivel en el que debe mejorarse la preparación de los módulos que se evalúan en la prueba de estado. Se obtuvo información de relevancia para contribuir en la toma de decisiones y el mejoramiento continuo tanto en los procesos de aprendizaje, como en el desempeño de los estudiantes en las pruebas Saber Pro. Con esto, se fortalecen los procesos implementados por el programa académico en pro de la reacreditación del programa académico en alta calidad.
Estrategia curricular para desarrollar habilidades tecnológicas en estudiantes de Ingeniería Química y Licenciatura en Ciencias Alimentarias
Authors: Matos Mosqueda Luisa , Crespo Zafra Lourdes Mariana , Benítez Cortés Isnel , Portuondo Padrón Roberto
Published: April 2024

El objetivo de este trabajo es diseñar una estrategia curricular para la formación y el desarrollo de habilidades prácticas tecnológicas en estudiantes de las carreras de Licenciatura en Ciencias Alimentarias e Ingeniería Química y se implementa en una Planta Piloto para la producción de alimentos. Se sustenta en la necesidad de establecer los componentes de la esfera de autorregulación cognitiva instrumental en unidad, a partir de la formación del componente instrumental, cognitivo y el metacognitivo. Se logra que el estudiante concientice los elementos del control y de la dirección de los procesos tecnológicos.
Futuro de la Ingeniería Industrial en las instituciones de educación superior de la ciudad de Bogotá
Authors: Sánchez Celis Juan Carlos , Santos Hernández Andrés Felipe , Rivera Rodríguez Hugo Alberto
Published: April 2024

El programa de ingeniería industrial ha venido experimentando una disminución en la cantidad de matriculados en primer curso en las Instituciones de Educación Superior acreditadas de la ciudad de Bogotá; cada vez son menos los estudiantes interesados en cursar esta carrera en esas instituciones según cifras del Sistema Nacional de Información para la Educación Superior. Mediante el Análisis Estructural de Sectores Estratégicos en este programa, se identificó la percepción de lo que ocurre en este subsector de la educación, a través de un tipo de investigación exploratoria, que busca, a partir de los resultados obtenidos, inferir algunos argumentos del fenómeno tratado, entre otros con la finalidad de proponer y documentar estrategias que contribuyan a la perdurabilidad del programa de ingeniería industrial en las Instituciones de Educación Superior acreditadas en la ciudad de Bogotá.
Frataxin deficiency shifts metabolism to promote reactive microglia via glucose catabolism
Authors: Sciarretta Francesca , Zaccaria Fabio , Ninni Andrea , Ceci Veronica , Turchi Riccardo , Apolloni Savina , Milani Martina , Della Valle Ilaria , Tiberi Marta , Chiurchiù Valerio , D’Ambrosi Nadia , Pedretti Silvia , Mitro Nico , Volontè Cinzia , Amadio Susanna , Aquilano Katia , Lettieri-Barbato Daniele
Published: April 2024

Immunometabolism investigates the intricate relationship between the immune system and cellular metabolism. This study delves into the consequences of mitochondrial frataxin (FXN) depletion, the primary cause of Friedreich’s ataxia (FRDA), a debilitating neurodegenerative condition characterized by impaired coordination and muscle control. By using single-cell RNA sequencing, we have identified distinct cellular clusters within the cerebellum of an FRDA mouse model, emphasizing a significant loss in the homeostatic response of microglial cells lacking FXN. Remarkably, these microglia deficient in FXN display heightened reactive responses to inflammatory stimuli. Furthermore, our metabolomic analyses reveal a shift towards glycolysis and itaconate production in these cells. Remarkably, treatment with butyrate counteracts these immunometabolic changes, triggering an antioxidant response via the itaconate-Nrf2-GSH pathways and suppressing the expression of inflammatory genes. Furthermore, we identify Hcar2 (GPR109A) as a mediator involved in restoring the homeostasis of microglia without FXN. Motor function tests conducted on FRDA mice underscore the neuroprotective attributes of butyrate supplementation, enhancing neuromotor performance. In conclusion, our findings elucidate the role of disrupted homeostatic function in cerebellar microglia in the pathogenesis of FRDA. Moreover, they underscore the potential of butyrate to mitigate inflammatory gene expression, correct metabolic imbalances, and improve neuromotor capabilities in FRDA.
Thermally Activated Delayed Fluorescence in Organic Semiconductors and Its Application in Light-Emitting Diodes
Authors: Melnykov Serhii , Helzhynskyy Igor , Bulavinets Tetiana , Stakhira Pavlo
Published: April 2024

The presence of the effect of thermally activated delayed fluorescence (TADF) in organic light-emitting materials (emitters), manifested in the "collecting" of triplet excitons in organic semiconductor complexes that do not contain noble metals, creates excellent prerequisites for the application of TADF materials in the technology of manufacturing organic light-emitting diodes (OLED). The significant progress in solving theoretical and technical problems, achieved in the process of development of highly efficient TADF materials, paves the way for the formation of the future of organic electronics. This review presents the analyses of the nature of the long-term fluorescence generation mechanism at the molecular level and the up-to-date strategies for designing TADF donor-acceptor materials, as well as exciplex intermolecular complexes. Special attention is focused on the analysis of TADF emitter ambipolar materials with a highly twisted, rigid molecular structure, which reveal a tendency towards the multi-channel emission mechanisms and their implementation in a variety of OLED structure architectures.
Cosmic Aspects of Sharma-Mittal Holographic Dark Energy Model in Brans-Dicke Theory of Gravity
Authors: Aditya Y. , Tejeswararao D. , Prasanthi U.Y. Divya
Published: April 2024

We investigate the cosmological scenario involving spatially homogeneous and anisotropic Bianchi type-V I0 space-time in the context of the Sharma-Mittal holographic dark energy model within the framework of Brans-Dicke’s theory of gravitation. In order to achieve this objective, the Hubble, deceleration, equation-of-state parameters have been discussed. The deceleration parameter (q) is used to measure the pace at which the expansion of the universe is accelerating. The equation-of-state parameter (ωsmhde) characterizes the quintessence and vacuum areas of the universe. All the parameters demonstrate consistent behaviour following the Planck 2018 data. We assess the dynamical stability by defining the squared speed of sound and examining its behaviour. In addition, the energy conditions and the variation of ωsmhde and ω′smhde in the model indicate the present accelerating expansion of the universe.
Spectral and Temporal Properties of CXOUJ122956.7+075728 (ULX-1), an Ultraluminous X-Ray Source in NGC 4472
Authors: Devi A. Senorita
Published: April 2024

This report presents a comprehensive analysis of the spectral and temporal characteristics of a highly significant Ultraluminous X-ray Source (ULX) designated as CXOUJ122956.7+075728 (ULX-1) situated in the elliptical galaxy NGC 4472 within the Virgo cluster. ULX-1 exhibits a soft spectral state, featuring a cool accretion disk component with kTin ∼ 0.15 keV, accompanied by a power-law tail displaying a steep power-law photon index, Γ ∼ 2.8. The spectral findings strongly support an estimated black hole mass of approximately 3.30 × 103 M⊙ under an isotropic emission model, and around 1.47 × 103 M⊙ in an extreme beaming scenario. Temporally, ULX-1 displays significant variability on time scales of 0.5, 1, and 2 ks, suggesting the possibility of instabilities within the accretion disk contributing to this behavior. However, despite this temporal variability, the power spectra analysis of this soft ULX reveals no signatures of pulsations, distinguishing it from certain pulsating ULXs (PULXs) typically associated with neutron stars. This absence of pulsations in ULX-1 further underscores its unique spectral and temporal characteristics within the broader context of ULX phenomena.
Traversable Wormholes in f(R) Gravity Sourced by a Cloud of Strings
Authors: Goswami Parangam , Baruah Anshuman , Deshamukhya Atri
Published: April 2024

Wormhole solutions in General Relativity (GR) require exotic matter sources that violate the null energy condition (NEC), and it is well-known that higher-order modifications of GR and some alternative matter sources can support wormholes. In this study, we explore the possibility of formulating traversable wormholes in f (R) modified gravity, which is perhaps the most widely discussed modification of GR, with two approaches. First, to investigate the effects of geometrical constraints on the global characteristics, we gauge the rr–component of the metric tensor and employ Padè approximation to check whether a well–constrained shape function can be formulated in this manner. We then derive the field equations with a background of string cloud and numerically analyse the energy conditions, stability, and amount of exotic matter in this space-time. Next, as an alternative source in a simple f (R) gravity model, we use the background cloud of strings to estimate the wormhole shape function and analyse the relevant properties of the space-time. These results are then compared with those of wormholes threaded by normal matter in the simple f (R) gravity model considered. The results demonstrate that string cloud is a viable source for wormholes with NEC violations; however, the wormhole space-times in the simple f (R) gravity model considered in this study are unstable.
Bianchi Type-III Viscous Holographic Ricci Dark energy Cosmological model in Brans-Dicke theory of Gravitation
Authors: Satyanarayana P.E. , Sireesha K.V.S.
Published: April 2024

This paper investigates and examines a wide range of findings related to the description of holographic Ricci dark energy (HRDE) with the bulk viscosity within Universe's late-time accelerated expansion in the framework of an anisotropic Bianchi type-III cosmological model with pressure-less matter content in the Brans-Dicke theory of gravity. We are using the relationship between the metric potentials to obtain a precise conclusion to the field equations, resulting in a rapid expansion. Several major cosmological parameters, including Hubble, deceleration, matter energy density, Ricci dark energy density (RDE), and Equation of state (EoS), are used to investigate the physical behavior of our dark energy model. We detected some of the viscosity of the holographic Ricci dark energy model using current cosmological observations. We describe how the model's physical and geometric properties are compatible with recent compilations.
Nonclassicalities of the Superposition State of Coherent and Photon-Added-Coherent State
Authors: Giri Sandip Kumar
Published: April 2024

The nonclassical properties of the hybrid coherent state (HCS), which is the superposition state of the coherent state and photon-added coherent (PAC) state, is investigated analytically. We evaluated the photon number statistics, the Wigner-Yanase skew information, the Mandel Q factor and the quadrature squeezing of the HCS to quantify its nonclassicality. This superposition state exhibits more nonclassical properties than the PAC state and even the superposition state of coherent state and single-photon-added coherent (SPAC) state. We reported that the addition of more photons to the PAC state part of the HCS generally quantifies more nonclassicalities. The nonclassical properties of the HCS also depend on the amplitudes of coherent state and the PAC state in the HCS.
Effects of Topological Defects and Magnetic Flux on Dissociation Energy of Quarkonium in an Anisotropic Plasma
Authors: Abu-Shady Mohamed , Inyang Etido P.
Published: April 2024

In this paper, we investigate the effects of anisotropic parameters, topological defects, and magnetic flux on the dissociation energy of bottomonium in an anisotropic quark-gluon plasma. We use the three-dimensional Schrödinger equation and derive the energy eigenvalues. Our findings show that the dissociation energy decreases with increasing temperature, but there is a slight shift towards higher values when the magnetic flux is increased. Furthermore, the inclusion of topological defects causes further shifts in the dissociation energy at high temperatures. Additionally, we analyze the impact of anisotropic medium on dissociation energy, both with and without considering topological defects. We observe that including topological defects results in higher values for the dissociation energy across all temperatures, while ignoring them leads to lower values at all temperatures studied. Moreover, we consider the baryonic chemical potential and find that its effect on dissociation is negligible compared to temperature variations. These findings provide valuable insights into the behavior of heavy quarkonium systems under different physical conditions and contribute to our understanding of topological effects in anisotropic media.
Weakly Nonlinear Bio-Thermal Convection in a Porous Media Layer Under Rotation, Gravity Modulation, and Heat Source
Authors: Kopp Michael I. , Yanovsky Volodymyr V.
Published: April 2024

In this paper, the influence of gravitational modulation on weakly nonlinear biothermal convection in a porous rotating layer is investigated. We consider a layer of porous medium saturated with Newtonian fluid, containing gyrotactic microorganisms, and subject to gravitational modulation, rotation, and internal heating. To analyze linear stability, it is sufficient to represent disturbances in the form of normal modes, while nonlinear analysis includes a truncated Fourier series containing a harmonic of the nonlinear interaction. A six-dimensional nonlinear Lorentz-type model is constructed, exhibiting both reflection symmetry and dissipation. We determined heat and mass transfer using a weakly nonlinear theory based on the representation of a truncated Fourier series. Additionally, the behavior of nonstationary Nusselt and Sherwood numbers was investigated by numerically solving finite amplitude equations. Applying the expansion of regular perturbations in a small parameter to a six-dimensional model of Lorentz equations with periodic coefficients, we obtained the Ginzburg-Landau (GL) equation. This equation describes the evolution of the finite amplitude of the onset of convection. The amplitude of convection in the unmodulated case is determined analytically and serves as a standard for comparison. The study examines the effect of various parameters on the system, including the Vadasz number, modified Rayleigh-Darcy number, Taylor number, cell eccentricity, and modulation parameters such as amplitude and frequency. By varying these parameters, in different cases, we analyzed heat and mass transfer, quantitatively expressed by the Nusselt and Sherwood numbers. It has been established that the modulation amplitude has a significant effect on the enhancement of heat and mass transfer, while the modulation frequency has a decreasing effect.
Influence of Exchange and Correlation Interactions on the Spin Polarized Electronic Structure and Magnetic Properties of Ga0.75Mn0.25P in the B3 Blende Structure
Authors: Bouteldja Noureddine , Belabbas Mohamed , Taleb Rachid
Published: April 2024

This study focuses on investigating the influence of exchange and correlation interactions on the spin polarized electronic structure and magnetic properties of Ga0.75Mn0.25P in the B3 Zinc Blende phase. First-principle calculations were performed by systematically varying the Hartree-Fock (HF) exchange (α) value from 0 to 25% using the onsite exact-exchange functional for the treatment of the correlated electrons. The electronic and magnetic properties unveil that Ga0.75Mn0.25P manifests a half-metallic ferromagnetic behaviour at deferent values of HF exchange. Moreover, as the fraction (α) parameter increases, the band gap increases, leading to modifications in the spin polarized band structures. Additionally, our investigations indicate that exchange and correlation interactions cause an increase in the lattice parameter and volume of the compound. Furthermore, these interactions result in a decrease in the magnetic moments of P and Ga atoms, while the Mn moments increase. These findings provide valuable insights into the behavior of Ga0.75Mn0.25P and offer potential applications in the design of spintronic devices.
Effect of Biosynthesized Silver Nanoparticles on The Optical, Structural, and Morphological Properties of TiO2 Nanocrystals
Authors: Tasiu Jamila , Onimisi Muhammad Y. , Yusuf Abubakar S. , Danladi Eli , Tasie Nicholas N.
Published: April 2024

The development of efficient metal doped semiconductors for Photovoltaic applications has gained a lot of research attention. In this present paper, pure and silver nanoparticles (AgNPs)-modified TiO2 nanocrystals (NCs) with different amount of AgNPs (say 50, 100, 150, 200, and 250 µL) were achieved and the effects of AgNPs on the TiO2 NCs were explored systematically. The optical, structural and morphological properties were probed using UV-visible spectrophotometer, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results of the optical studies showed a characteristic peak of TiO2 and the redshifting of the peak position was observed by introducing AgNPs. The synergetic effects from AgNPs and TiO2 results to diminished band gap. The XRD result confirmed the formation of a tetragonal anatase TiO2 phase with a decrease in crystallite size with increasing AgNPs content. The SEM images show enhanced nucleation and film growth with presence of shining surface which can be seen to contribute to good photon management by enhancing light scattering. The unadulterated TiO2 and AgNPs-modified TiO2 have spherical morphology and uniform size distribution ranging from 20 to 30 nm. This study established the view that surface modification of TiO2 with AgNPs is a viable approach towards achieving an efficient light photocatalyst.
Tribological Properties at 20 and 500°C of TiN and CrN Cathodic ARC Coatings Deposited on Ti-6Al-4V Alloy
Authors: Klimenko Illya O. , Belous Vitaliy A. , Podhurska Viktoriya Ya. , Ostash Orest P. , Ovcharenko Valeriy D. , Tolmachova Galyna N. , Kolodiy Igor V. , Ishchenko Mykhailo G. , Babayev Ivan M. , Kuprin Oleksandr S.
Published: April 2024

Tribological properties of TiN and CrN coatings deposited by cathodic arc method at three different bias potentials -50, -150 and -300V on Ti-6Al-4V alloy in pair with alumina have been investigated. X-ray diffraction analysis showed that single-phase textured cubic nitrides of TiN and CrN were formed in these coatings. It is shown that the friction coefficient of the coatings is practically equal to that established for the Ti6Al4V alloy, but the wear rate is more than an order of magnitude lower than for the titanium alloy substrate. Coatings deposited at a potential of -50 V show optimal tribological properties at temperatures 20 and 500°C. Friction coefficients for TiN coatings are 0.4-0.8 at 20°C and 0,75 at 500°C; for CrN coatings they are 0.5 at 20°C and 0,7 at 500°C. Wear rates for TiN coatings are 0.86·10-5 мм3/Нм at 20°C and 3.56·10-5 мм3/Нм at 500°C; for CrN coatings they are 1.43·10-5 мм3/Нм at 20°C and 7.13·10-5 мм3/Нм at 500°C.
Single and Multiphoton Optical Transitions in Atomically Thin Layers of Transition Metal Dichalcogenides
Authors: Rasulov Rustam Y. , Rasulov Voxob R. , Urinova Kamolakhon K. , Mamatova Makhliyo A. , Akhmedov Bakhodir B.
Published: April 2024

The article discusses the production and properties of two-dimensional atomic layers of transition metal dichalcogenides (TMDs), focusing on the optical properties of monolayers. It begins with an introduction to the discovery of graphene production methods and the subsequent interest in TMDs. The basic properties of TMD monolayers, their crystal structure, and Brillouin zone are detailed. The article explores the energy spectrum of electrons in different valleys and the effective Hamiltonian describing states in parallel spin bands. The discussion extends to the matrix elements of interband optical transitions, including single-, two-, and three-photon transitions. Equations are provided to calculate probabilities of optical transitions, incorporating factors such as polarization vector, frequency of light, and temperature of the sample. Theoretical analysis of constituent matrix elements for these transitions is outlined, emphasizing quantum mechanical aspects. The article contributes researching of the optical behavior of transition metal dichalcogenides (TMDs) monolayers, particularly in structures with complex compositions.
Thermographic Method of Activated Carbon Packing Quality Diagnostics in NPP Air Filters
Authors: Azarenkov Mykola , Lytvynenko Volodymyr , Kolenov Ivan , Haluza Oleksii , Chupikov Anatoly , Sokolenko Volodymyr , Roskoshna Olena , Kanishcheva Mariya , Shatov Valeriy
Published: April 2024

The work is devoted to the tasks of safe operation of nuclear power plants, namely the prevention of inert radioactive gases, iodine, and its compounds from entering the air. The latter is particularly dangerous because it can accumulate in the human body. One of the methods of air purification is the use of air filters filled with activated carbon granules that have undergone preliminary treatment of thermal expansion and impregnation. At the same time, there is a problem with evaluating the change in local aerodynamic resistance as a result of the shape change of granules and their compaction when activated carbon is filled into the filter. For this purpose, the model that calculates the spatial field of movement of ventilation gases through a chamber that simulates an adsorber of the AU-1500 type filled with carbon granules was created. To verify the model, it was necessary to develop approaches to the assessment of the topology of the intergranular space and to draw up ideas about the possible inhomogeneities of such topology due to inhomogeneities in the compaction of granules during backfilling and vibration effects during operation. Therefore, an experimental model based on the assumption that air passage channels are spatially contiguous with electric current passage channels if a potential difference is applied to the "input-output" sections was proposed. Clusters of areas with heterogeneous packing by measuring the temperature distribution, which is released in the form of Joule heat were identified. Correlations between the characteristics of the spread of temperature fields and modes of current trans-mission have been established. It is shown that the obtained experimental data correlate with theoretical calculations of the flow of ventilation gases. The created set of methods allows optimization of the aerodynamic characteristics of the filter to improve their functional properties.
Temperature Dependence of Dielectric Relaxation of Absorption Spectra in the Chlorobenzene Iodobenzene System
Authors: Azizov Samir
Published: April 2024

The article presents the results of a study of the temperature dependence of the dielectric constant ε' and the dielectric loss index ε" of the chlorobenzene-iodobenzene system at wavelengths λ = 6.32; 4.01; 3.21; 2.14; 1.18 and 0.75 V temperature range ‑40℃÷+30℃. The static dielectric constant was determined at a frequency of 7 MHz. The temperature dependence of the time of dielectric relaxation of molecules in the liquid state was determined. It was established that in the specified temperature‑frequency range the dispersion region consists of two parts. Analysis of the temperature dependence of dielectric polarization relaxation in the system chlorobenzene-iodobenzene shows that the relaxation times of the components do not depend on their short-range order. It was also discovered that the rate graph showing the dependence of the logarithm of the relaxation time on the reciprocal of the temperature logτ ~ 1/T, consists of two parts and the value of the static dielectric permeability ε∞ is non-additive. To explain these results, it is assumed that clusters are formed in this system, the same as in the pure components.
Mechanism of Hydrogen Production in The Processes of Radiation Heterogeneous Splitting of Water with the Presence of Nano-Metal and Nano-MeO
Authors: Garibov Adil , Jafarov Yadigar , Imanova Gunel , Agayev Teymur , Bashirova Sevinj , Aliyev Anar
Published: April 2024

In the study, the optimal values of the ratio of the distance between particles to the particle size in the radiation-heterogeneous radiolysis of water in nano-Me and nano-MeO systems were determined. In those systems, the effect of water density and system temperature on the radiation-chemical release of molecular hydrogen obtained from thermal and radiation-thermal decomposition of water was considered. The article also determined the effect of particle sizes and the type of sample taken on the radiation chemical yield of molecular hydrogen. In the presented article, the change of molecular hydrogen according to adsorbed water and catalyst was studied. Thus, in the case of a suspension of nano-zirconium in water, the energy of electrons emitted from the metal is completely transferred to water molecules, which leads to an increase in the yield of hydrogen. When radiolysis of water in the presence of nano-metals, energy transfer can be carried out mainly with the participation of emitted electrons. Therefore, in the case of radiolysis of water in suspension with n-Zr, the yield of hydrogen increases by 5.4 times compared to the processes of radiolysis in an adsorbed state. However, in radiation-heterogeneous processes of obtaining hydrogen from water in contact with metal systems, it is necessary to take into account that as a result of these processes surface oxidation occurs and after a certain time the systems are converted to n-Me-MeO+H2Oliq. systems. For nano sized oxide compounds, the mean free path of secondary electrons formed as a result of primary processes of interaction of quanta with atoms is commensurate with the particle sizes of nano-oxides (λ ≈ R_(H-оxides)). Further, these electrons interact with the electronic subsystem of silicon. For nanocatalysts, the length of free paths of secondary and subsequent generations of electrons is greater than the size of catalyst particles (R_cat≤100nm). Usually, their energy is sufficient to conduct independent radiolytic processes in the contact medium of the catalyst.
Sustainable urban infrastructure: A comprehensive review of environmental safety practices in civil engineering
Authors: Jamal Mohamed Ibrahim F.
Published: April 2024

This comprehensive review paper addresses the contemporary challenges and future trajectories in the domain of sustainable urban infrastructure within civil engineering. The escalating pace of urbanization demands immediate transformative measures, underscoring the joint responsibility of the civil engineering community to construct cities that are not only habitable but also inclusive and environmentally conscious. The document extensively examines critical facets, including green building design, renewable energy integration, sustainable water management, and waste reduction and recycling. The prioritization of research endeavors in these domains is intricately linked to regional needs, environmental complexities, and societal preferences. Throughout the review, there is a consistent emphasis on the indispensable role of sustainable and resilient practices in the development of urban infrastructure, stressing the necessity for innovative solutions to address the intricate interplay of factors influencing urban environments. The concluding remarks underscore the urgency for the civil engineering community to spearhead the implementation of transformative practices, contributing to the evolution of cities that are not only resilient but also pivotal in fostering a sustainable and equitable future.
A step by step analysis to solve the equation of motion in space and time using basis splines - A class room example
Authors: Chandrasekhar K. N. V.
Published: April 2024

The use of splines to model the geometry and perform iso-geometric analysis is fast replacing conventional finite element analysis. In this paper, the main objective is to analyze the equation of motion using basis splines. The equation of motion is a function of both space and time. The finite difference method is used to evaluate the newer values of the function at each time step. The splines are used to determine the mass matrix and the stiffness matrix. The sample code is also presented. The displacement vector at each time step is shown using graphs. The graphs clearly show how the member vibrates at each time step and the state of the beam. The analysis clearly shows how the Galerkin method can be applied with a weak formulation to solve for the displacement vector in a step-by-step method. Two problems are discussed, the first is a classroom example, and the second is a home work example, which may require a bit of effort to determine the value of the nodal displacement vector at several nodes for each time step.
Preface
Authors: Burakowski Wojciech , Stokłosa Janusz
Published: April 2024

Preface
Coherence of radial implicative fuzzy systems with nominal consequents
Authors: Coufal David
Published: April 2024

In the paper we are interested in the question of coherence of radial implicative fuzzy systems with nominal consequents (radial I-FSs with NCs). Implicative fuzzy systems are fuzzy systems employing residuated fuzzy implications for representation of IF-THEN structure of their rules. Radial fuzzy systems are fuzzy systems exhibiting the radial property in antecedents of their rules. The property simplifies computational model of radial systems and makes the investigation of their properties more tractable. A fuzzy system has nominal consequents if its output is defined on a finite unordered set of possible actions which are generally quantitatively incomparable. The question of coherence is the question of under which conditions we are assured that regardless the input to the system is, an output of the system exists, i.e., the output is non-empty. In other words, a fuzzy system is coherent if it has no contradictory rules in its rule base. In the paper we state sufficient conditions for a radial I-FS with NCs to be coherent
Low Complexity Greedy Power Allocation Algorithm for Proportional Resource Allocation in Multi-User OFDM Systems
Authors: Dessouky Moawad I. , Al-Hanafy Waleed E. , Odhah Najib A. , El-Samie Fathi E. Abd
Published: April 2024

Multi-User Orthogonal Frequency Division Multiplexing (MU-OFDM) is an efficient technique for achieving high downlink capacity in high-speed communication systems. A key issue in MU-OFDM is the allocation of the OFDM subcarriers and power to users sharing the channel. In this paper a proportional rate-adaptive resource allocation algorithm for MU-OFDM is presented. Subcarrier and power allocation are carried out sequentially to reduce the complexity. The low complexity proportional subcarriers allocation is followed by Greedy Power Allocation (GPA) to solve the rate-adaptive resource allocation problem with proportional rate constraints for MU-OFDM systems. It improves the work of Wong et al. in this area by introducing an optimal GPA that achieves approximate rate proportionality, while maximizing the total sum-rate capacity of MU-OFDM. It is shown through simulation that the proposed GPA algorithm performs better than the algorithm of Wong et al., by achieving higher total capacities with the same computational complexity, especially, at larger number of users and roughly satisfying user rate proportionality.
Skill-Based Bimanual Manipulation Planning
Authors: Szynkiewicz Wojciech
Published: April 2024

The paper focuses on specification and utilization of manipulation skills to facilitate programming of bimanual manipulation tasks. Manipulation skills are actions to reach predefined goals. They constitute an interface between low-level constraint-based task specification and high level symbolic task planning. The task of the robot can be decomposed into subtasks that can be resolved using manipulation skills. Rubik’s cube solving problem is presented as an example of a 3D manipulation task using two-arm robot system with diverse sensors such as vision, force/torque, tactile sensors.
Optimizing the Structure of Vector Bend and Strain Sensor on the Base of Three-Core Microstructured Fiber
Authors: Goncharenko Igor A. , Marciniak Marian , Konojko Alexei I. , Reabtsev Vitaly N.
Published: April 2024

In the paper the optical sensor allowing measuring a direction, values and localization of bends and stresses in building structures is described. The sensitive element of the sensor is the microstructured fiber with three cores. The use of three-core fiber makes it possible to define the direction of deformation. Distribution of mode fields in fiber cores depending on fiber structure and bend value and direction is analyzed. The optimization of the sensitive element parameters depending on the application is proposed.
High Q-factor Fabry-Perot Microresonator as an Alternative to Microdisk in Electro-Optical Modulator for Microwave-Photonic Receivers
Authors: Baghdasaryan Hovik V. , Marciniak Marian , Knyazyan Tamara M.
Published: April 2024

In the last decade a new idea has been suggested for receivers of communication systems, namely, in microwave receivers’ architecture. Though superheterodyne radio-frequency receivers are best suited to the needs of contemporary wireless communication, however stray radiation of their local oscillator (heterodyne) interferes with neighboring radio-devices and permits to locate the covert receiver. To overcome this drawback the signal transfer to optical range has been suggested. By this conversion, not only an elimination of receiver’s stray radiation is attained but also vast advantages of photonic signal processing become available. The key element of existing microwave-photonic receivers is electro-optical microdisk modulator. However, its realization is complicated and as an alternative an electro-optical modulator based on high Q-factor Fabry-Perot microresonator is suggested. Comparative analysis of both types of modulators is performed, and advantages of high Q-factor Fabry-Perot microresonator based modulator are highlighted.
Traffic Type Influence on Performance of OSPF QoS Routing
Authors: Czarkowski Michał , Wolff Maciej , Kaczmarek Sylwester
Published: April 2024

Feasibility studies with QoS routing proved that the network traffic type has influence on routing performance. In this work influence of self-similar traffic for network with DiffServ architecture and OSPF QoS routing has been verified. Analysis has been done for three traffic classes. Multiplexed On-Off model was used for self-similar traffic generation. Comparison of simulation results was presented using both relative and non-relative measures for three traffic classes. Results were commented and analyzed. The basic conclusion is that performance for streaming and best-effort class for self-similar traffic is higher than performance for the same class with exponential traffic (Poisson). The other important conclusion is relation between performance differences and offered traffic amount.
Minimizing Cost of Network Upgrade for Overlay Multicast – Heuristic Approach
Authors: Szostak Maciej , Walkowiak Krzysztof
Published: April 2024

A rapid increase of the Internet users and traffic at the rate of 31% in years 2011–2016 contributes to emerging of new approaches to the content distribution. Among other approaches, the overlay multicasting seems to be one of the most interesting concepts according to relatively low deployment costs and large scalability. In this paper, the authors formulate a new incremental multicast overlay design problem. In particular, authors assumed that the overlay network is to be upgraded due to an increase of the number of participating users and the need to improve the streaming quality. However, the existing multicast tree structure is assumed to remain fixed. The goal was to minimize the cost of the upgrade, represented in euro/month. To achieve it, for each peer participating in the transmission, a link type offered by one of the ISPs was selected and overlay trees were constructed, rooted at the source of the content. The authors also present a new heuristic algorithm to efficiently solve this problem. According to experiments, the biggest factor influencing the upgrade cost and determining possible streaming quality values that the system can be upgraded to is the initial tree structure.
Interworking and Cross-layer Service Discovery Extensions for IEEE 802.11s Wireless Mesh Standard
Authors: Gierłowski Krzysztof
Published: April 2024

With the rapid popularization of mobile end-user electronic devices, wireless network technologies begin to play a crucial role as networks access technologies. While classic point-to-multipoint wireless access systems, based on fixed infrastructure of base stations providing access to clients, remain the main most popular solution, an increasing attentionis devoted to wireless mesh systems, where each connecting client can extend overall resources of the network by becoming a network node capable of forwarding transit traffic. This ability results in severe reduction of the necessary network infrastructure, provides through coverage (thereby offering significant step towards ubiquity of network access) and offers massive redundancy. One of the most promising wireless mesh solutions currently being developed is an IEEE 802.11s standard, based on popular Wi-Fi technology. It combines low deployment costs with comprehensive suite of mechanisms able to operate a self-forming, autoconfigurable, dynamically extending, and secure mesh solution. However, despite its advantages, the standard lacks sufficient support for a number of functionalities, which can lead to significant inefficiency and degradation of service quality in real-world IEEE 802.11s network deployments. In the paper we propose a number of extensions of IEEE 802.11s mechanisms, designed to provide better service quality in case of real-world deployment scenarios, especially in case of large systems. Both propositions introduce modifications to mesh path discovery and interworking procedures, while retaining compatibility with standard solution. Their basic functionality and efficiency have been verified by means of simulation model in large-scale, self-organizing mesh structure. Subsequently they have been implemented and tested in real-world, access network testbed deployment. The results clearly indicate their utility, particularly in case of larger deployments of this network system type.