Energy Parameters Research Articles

Ductility and cracking behavior of UHPC-RC composite beam under bending test based on acoustic emission parameters

Ultrahigh-performance concrete (UHPC) possesses improved mechanical properties due to its high strength, durability, and toughness. Currently, there is a single method for detecting the cracking behavior and evaluating the ductility of the UHPC-reinforced concrete (RC) composite beam. As an important part of structural non-destructive monitoring techniques, the acoustic emission (AE) technique can be used to analyze the damage pattern of the structure by the variation characteristics of its individual parameters. On this basis, four-point bending tests were carried out on the RC beam and UHPC-RC composite beam, and the AE technique was used for ductility analysis and cracking behavior monitoring. The results showed that the UHPC material enhanced the flexural capacity of the UHPC-RC composite beam. The AE ring counts and energy parameters could be used to analyze the cracking process of the UHPC-RC composite beam during flexural damage. The proposed new ductility indices, AE ring counts ductility index (ARD) and AE energy ductility index (AED), differed from the displacement ductility indices within the range of 2 %, providing a new method for calculating ductility indices of concrete structures. During the failure stage, the UHPC-RC composite beam produced more tensile cracks at the early stage of cracking and the stage of damage compared to the RC beam. In addition, the b value of the RC beam had a large range of fluctuations during the failure stage, indicating that the RC beam produced more micro-cracks and macro-cracks and more damage compared to the UHPC-RC composite beam.

LUMINI PACKAGE FOR AB INITIO MODELING OF DOSIMETRIC EXPERIMENTS

The paper presents the capabilities of the new Lumini code for ab initio modeling of dosimeter efficiency parameters. It is based on a scaling method that allows unifying the parameters of the kinetic model of the dosimeter without the numerous approximations used to interpret experimental results of thermal-, phosphorescence, and partial illumination of irradiated semiconductors. For the first time, the Monte Carlo method was used to consider the influence of statistical fluctuations in the energy and kinetic parameters of the model on the dosimetric parameters of typical dosimeters. As a first step, the data of Lumini's interpretation of the experimental TLD spectra of 500K dosimeters irradiated on the M-30 microtron was discussed.

Spin-Dependent Regulation of The Electronic and Magnetic Properties of Poly(3-Alkylthiophene) Oligomers and Their Composites with Aromatic Nanoadditives

The energy and spin parameters of poly(3-alkylthiophene) oligomers and their composites with aromatic hydrocarbons are calculated. The coexistence of polarons with different degrees of delocalization in the studied compounds has been identified. Periodic changes in the electronic and spin properties of composites were detected, initiated by the interaction of oligomers with aromatic nanoadditives. The anisotropic parameters of the spin Hamiltonians of the studied systems are obtained and their high-resolution EPR spectra are calculated.

Kinetic investigation on palladium‐catalyzed carbonylation of allyl alcohol

AbstractPalladium‐catalyzed carbonylation of allyl alcohol to 3‐butenoic acid has been investigated. A significant effect of halide promoters, p‐tolylsulfonic acid (TsOH), water, solvents, and PPh3 concentration activity and selectivity has been studied. Detailed kinetics of this reaction was investigated in a temperature range of 363–383 K. The influence of parameters such as stirring speed, allyl alcohol, catalyst, benzyltriethylammonium chloride (BTEAC), TsOH concentrations, and CO partial pressures on the activity and selectivity has been studied. An empirical rate equation was suggested and found to be fairly consistent with observed rate data. In addition, the activation energy and kinetic parameters were evaluated.

Evaluation framework for bitumen-aggregate interfacial adhesion incorporating pull-off test and fluorescence tracing method

The interfacial adhesion between bitumen and aggregate is crucial to maintain the mechanical performance of asphalt pavement. Numerous indicators characterize the bonding ability of bitumen to aggregate; however, indicators based on limited conditions are used infrequently to effectively evaluate the interfacial adhesion between bitumen and aggregate. This study introduces a method to assess adhesion and moisture damage resistance at the bitumen-aggregate interface by combining the pull-off test with the fluorescence tracing method. The improved pull-off test considers different bitumen film thicknesses, ambient temperatures, material combinations, and moisture damage conditions, and the fluorescence tracing method and surface energy parameters are utilized to precisely detect the extent of bitumen adherence to the aggregate. The findings of this study are summarized as follows. (1) The bitumen stripping ratio characterizes the influence of ambient temperature and bitumen film thickness, and the pull-off strength/work quantifies the influence of ambient temperature and material combination. (2) The indicators derived from surface free energy theory exhibit lower sensitivity to material combinations compared with the pull-off performance indicators, with a coefficient of variation for both adhesion and stripping work of approximately 6 % compared to 14.29 %–70.13 % for the pull-off performance indicators. (3) The pull-off strength indicator dominates the pull-off performance evaluation, with the bitumen stripping ratio necessary at 0°C and pull-off work significant at 40°C to evaluate adhesive properties. In addition, the bitumen stripping ratio increment should be considered alongside pull-off strength loss ratio when estimating anti-moisture damage performance. (4) The fluorescence tracing method shows great potential in terms of enhancing the accuracy of bitumen stripping ratio detection in the pull-off test, with bitumen stripping ratio discrepancies at 0°C–40°C ranging from 0.98 % to 7.16 % for 70#-Limestone and 2.10–9.21 % for 70#-Granite. The methodology presented in this study represents a promising framework to determine the interfacial adhesive properties of asphalt mixtures with high accuracy.

Electronic Descriptor to Identify the Activity of SACs for E-NRR and Effect of BF3 as Electrolyte Ion.

Electrochemical nitrogen reduction reaction (e-NRR) is an eco-friendly alternative approach to generate ammonia under ambient conditions, with very low power supply. But, developing of an efficient catalyst by suppressing parallel hydrogen evolution reaction as well as avoiding the catalysts poisoning either by hydrogen or electrolyte ion is an open question. So, in order to screen the single atom catalysts (SACs) for the e-NRR, we proposed a descriptor-based approach using density functional theory (DFT) based calculations. We investigated total 24 different SACs of types TM-Pc, TM-N3C1, TM-N2C2, TM-NC3 and TM-N4, considering transition metal (TM). We have considered mainly BF3 ion to understand the role of electrolyte and extended the study for four more electrolyte ions, Cl, ClO4, SO4, OH. Herein, to predict catalytic activity for a given catalyst we have tested 16 different electronic parameters. Out of those, electronic parameter dxz↓ occupancy, identified as electronic descriptor, is showing an excellent linear correlation with catalytic activity (R2=0.86). Furthermore, the selectivity of e-NRR over HER is defined by using an energy parameter ▵G*H-▵G*NNH. Further, the electronic descriptor (dxz↓ occupancy) can be used to predict promising catalysts for e-NRR, thus reducing the efforts on designing future single atom catalysts (SACs).

Substantiation of the methodology for calculating the design of a small-sized hydraulic pulse vibrator

A methodology for the design calculation of a new design of a hydraulic pulse vibrator with a valve pressure pulse generator of a parametric type has been developed, which allows determining its energy, power and geometric parameters.

Recent perspective on polymeric Semimetal (Si, Ge and As) and nonmetal (N and P) doped C70-Fullerene system: Comparative electronic, dynamic behavior and chemotherapy docking with ADMET analysis

Fullerene system, based on carbon atoms, was studied and its structural modification was built with consideration of several elements such as Si, N, P, Ge, and As, where doped modified systems were constructed. Synthetic routes survey was considered to acquire the structures' availability in further applications related to structure properties investigation. The computational investigation of these designed systems was described using the most popular approach of density functional theory (DFT). Electronic behavior for all systems was studied especially through density of states (DOS) spectra, molecular electrostatic potential (MEP), and frontier molecular orbitals (FMOs) for best comparison towards stability with less energetic properties, where C-fullerene was predicted as a more stable candidate as its ∆E with value of 1.714 eV. Molecular dynamic simulation (MD) was considered to predict the stability of the atoms in the system during the physical movement at 100 ps. A polymeric model of triple Fullerene rings was linked for each Semimetal atom (Si, Ge, and As) to predict the radial distribution function (RDF) and dynamic behavior for stability conditions. The calculated energy parameters such as potential, kinetic, and non-bond energies mainly described the system movement stability during the simulation time. Molecular docking analysis of the modified doped systems was performed for chemotherapy prediction of the studied systems against breast cancer target protein (5NWH) to evaluate the inhibition strength through active sites binding affinity. The estimated binding affinity of Si-fullerene was found the most favorable result (-12.73 kcal/mol). ADMET properties were estimated for further drug-like prediction through comparative pharmacokinetic factors.

Mathematical modeling for the efficiency function of the Retiro small hydroelectric power plant turbine-generator set

ABSTRACT Many authors use an efficiency constant for the turbine-generator set to calculate energy generation in hydroelectric projects. This often does not reflect reality because the efficiency of this system is relative and is related to the potential of the net head height and the flow of turbine discharge. The present work aims to perform a mathematical modeling for an analysis of the efficiency of the Turbine-Generator Small Hydroelectric Power Plant (SHPP) Retiro. To perform this analysis, a model based on a second-degree polynomial function was employed. A multivariate regression technique was applied by the Least Square Method (LSM) to obtain the coefficients of the function. To verify the behavior of the measured and adjusted data, the Determination Coefficient (R2) of Root Mean Square Error (RMSE) algorithm was applied. The RMSE Mean of 0.022 and the RMSE Std of 0.029 suggest that the second-degree polynomial function is more consistent and stable across different training and validation datasets. The R2 value of 0.993 indicates that 99.3% of the variability in the data is explained by the model. The Omnibus, Durbin-Watson, and Jarque-Bera tests were applied to diagnose potential issues related to normality, autocorrelation, and adequacy, thereby validating the accuracy and significance of the model. The Hessian matrix technique was also used to verify the critical points of the function. The critical point corresponding to a water head of 11.47 meters and a turbine flow of 145.1 m3/s presented the highest operational efficiency. This study allows presenting a turbine efficiency function, its Hill Curve and a generator efficiency function with its corresponding Efficiency Curve. For efficiency analysis in several flow, height and power settings. The technique has proved efficient and can be an applicable tool in energy parameter studies for other hydroelectric projects with the same characteristics as SHPP Retiro.

Analysis of thermophoretic and Brownian diffusions in hydromagnetic curvilinear flow of Carreau nanofluid with activation energy and heat generation

This study presents a theoretical analysis of the thermophoretic and Brownian diffusion effects on the magnetized flow of Carreau nanofluid over a stretchable curved surface. The investigation includes the impact of heat generation and activation energy, which are incorporated into the energy and concentration equations, respectively. The mathematical model of the boundary layer flow is formulated as a set of nonlinear partial differential equations using curvilinear coordinates. These equations are transformed into ordinary differential equations through the application of appropriate similarity variables. The resulting system is solved numerically by using the shooting method along with the Runge-Kutta technique. The accuracy of the numerical results is further verified by the Keller-box method, a finite difference technique. The obtained results are also checked by giving a comparison table with the published data in the literature. Furthermore, the convergence of the solutions is also checked by a convergent series method known as the homotopy analysis method (HAM). The study examines the influence of several key parameters, including the radius of curvature, Weissenberg number, Prandtl number, Lewis number, Brownian and thermophoretic diffusions parameters, Hartmann number, heat generation parameter, activation energy parameter, temperature difference parameter, chemical reaction parameter, and power law index. The effects of these parameters on momentum, temperature, concentration distributions, mass and heat transfer rates, and as well as the skin friction coefficient are examined through graphs and tables. Graphical observations declare that the velocity field diminishes against the rising values of the Hartmann number and Weissenberg number. However, the velocity profile rises with improved values of the radius of curvature parameter and power law index parameter. It is also noticed that the magnitude of the concentration field rises with growing values of the Brownian parameter, activation energy parameter and Lewis number, whereas it shows a decreasing manner against the enhanced values of the thermophoresis parameter and temperature difference parameter.

Investigation of PCVSi− defect in 4H–SiC as a candidate for a qubit

Abstract Exploration of spin defects in semiconductors for possible qubits encourages the development of the quantum field. Silicon carbide (SiC) is a suitable platform to carry spin defects, due to its excellent electrical, mechanical and optical properties, together with its convenience for crystallographic growth and doping processes. In this study, a negatively charged phosphorus-vacancy (PCVSi −) defect, consisting of a silicon vacancy and nearby substitution of a phosphorus atom to a carbon atom in 4H–SiC, is investigated by first-principles calculations. This defect is demonstrated to possess a high spin (S = 1) with relatively low formation energy. Computed zero-phonon line energy and zero-field splitting parameters of this defect are close to those of neutral divacancy (VCVSi 0), negatively charged nitrogen-vacancy center (NCVSi −) and some other color centers, which indicate a similarity of both optical and spin properties among them. Moreover, the electron spin coherence time of this defect turns out to be 1.15–1.40 ms. Such a long coherence time provides the defect with reliability for quantum information processing. Our results show that the PCVSi − defect can be a promising candidate for a qubit.

Navigating Ball Mill Specifications for Theory-to-Practice Reproducibility in Mechanochemistry.

The rising prospects of mechanochemically assisted syntheses hold promise for both academia and industry, yet they face challenges in understanding and, therefore, anticipating respective reaction kinetics. Particularly, dependencies based on variations in milling equipment remain little understood and globally overlooked. This study aims to address this issue by identifying critical parameters through kinematic models, facilitating the reproducibility of mechanochemical reactions across the most prominent mills in laboratory settings, namely planetary and mixer mills. Through a series of selected experiments replicating major classes of organic, organometallic, transition metal-catalyzed, and inorganic reactions from literature, we rationalize the independence of kinematic parameters on reaction kinetics when the accumulated energy criterion is met. As a step forward and to facilitate the practicability of our findings, we provide a freely accessible online tool[†] that allows the calculation of respective energy parameters for different planetary and mixer mills. Our work advances the current understanding of mechanochemistry and lays the foundation for future rational exploration in this rapidly evolving field.

Electroosmotically assisted peristaltic propulsion of blood-based hybrid nanofluid through an endoscope with activation energy

The main aim of this research work is to analyze the peristaltic pumping of hybrid nanofluid through an endoscope. Here, blood is considered as base fluid and iron-oxide and gold are considered as nanoparticles. The non-Newtonian behavior of blood is studied through the Casson fluid model. The effect of nanoparticles is included in the mathematical formulation by using the modified version of Buongiorno model. Moreover, the effects of motion due to electroosmosis, activation energy, and Joule heating are also considered in fluid flow. The obtained non-linear system of equations after imposing lubrication approach is solved using Mathematica. The flow properties subject to variation in different involved parameters is analyzed through graphical results. It is assessed from graphical results that for larger Casson fluid parameters, fluid flow is more accelerated. It is also observed that presence of hybrid nanoparticles improves the velocity profile as well as cooling tendency of the working fluid when compared with the case of mono nanofluid. The electroosmotic phenomenon works a key parameter that can control the fluid flow by either assisting and opposing the flow. It has observed that a larger Debye length parameter, assisting electric field, and larger activation energy parameter reduce the nanoparticle concentration.

Navigating Ball Mill Specifications for Theory‐to‐Practice Reproducibility in Mechanochemistry

AbstractThe rising prospects of mechanochemically assisted syntheses hold promise for both academia and industry, yet they face challenges in understanding and, therefore, anticipating respective reaction kinetics. Particularly, dependencies based on variations in milling equipment remain little understood and globally overlooked. This study aims to address this issue by identifying critical parameters through kinematic models, facilitating the reproducibility of mechanochemical reactions across the most prominent mills in laboratory settings, namely planetary and mixer mills. Through a series of selected experiments replicating major classes of organic, organometallic, transition metal‐catalyzed, and inorganic reactions from literature, we rationalize the independence of kinematic parameters on reaction kinetics when the accumulated energy criterion is met. As a step forward and to facilitate the practicability of our findings, we provide a freely accessible online tool[†] that allows the calculation of respective energy parameters for different planetary and mixer mills. Our work advances the current understanding of mechanochemistry and lays the foundation for future rational exploration in this rapidly evolving field.

Influence of couple stress, radiation, and activation energy on MHD flow and entropy generation in Maxwell hybrid nanofluid flow over a flat plate

Countless engineering applications rely on heat and mass transportation technologies. Limitations in thermal conductivity and mass diffusivity are common in conventional fluids. Nanofluids, which are essentially base fluids with nanoparticles suspended in them, have superior thermal characteristics than base fluids without the nanoparticles. Maxwell hybrid nanofluids have the potential to improve mass and heat transport even further by combining the characteristics of two different types of nanoparticles. The magnetohydrodynamic (MHD) flow and heat transmission properties of a Maxwell hybrid nanofluid through a flat plate are investigated in this work. The novelty of this research lies in its exploration of the combined impressions of couple stress and activation energy on the flow behaviour. The equations governing the problem undergo transformation and are handled by means of the bvp4c solver. The vital discoveries disclose that the nanoparticle concentration and magnetic field strength act as opposing forces to fluid velocity. And also, it is detected that the friction coefficient rises by 2.68% as the value of volume fraction of copper nanoparticles ranges from 0 to 0.105. It is found that there is a decrement of 29.7% in the heat transmission rate when the values of Eckert number lie between 0 and 0.6. It is observed that the reaction rate and activation energy parameters play opposite roles against fluid concentration. It is discovered that the entropy generation increases with factors that enhance friction and heat dissipation (Maxwell and Brinkman parameters). The results show that the Sherwood number drops 4.4% when the activation energy parameter is set to values between 0 and 3.

Correlation of Water and Energy Parameters in a South of Minas Gerais Water Supply System

Objective: The objective of this study is to investigate the correlation between water and energy parameters in order to obtain water and energy consumption, according to studies by a local water utility. Theoretical Framework: The main theories presented here are the water and energy balances of a water supply network, whose authors can be found throughout the work. Such concepts are fundamental, as they allow correlating the parameters that are the objective of the study. Method: The methodology adopted for this research comprises a literature review to obtain the necessary theoretical basis, as well as data collection carried out through campaigns by the research group throughout its trajectory, in previous works. The processing of the collected data was carried out using water and energy balances, with the consequent correlation of such parameters in relation to water losses in the sector under study. Results and Discussion: The results obtained revealed that losses can reach up to R$249,949.06 in 5 years in the sector under study, reconciling water and energy losses due to the inefficiency of the system under study. Research Implications: This research, due to its approach, can guide measures to increase water and energy efficiency in sanitation companies, resulting in important financial and environmental gains for society by reducing water and energy waste and reducing operating costs, with resulting financial relief for society. Originality/Value: This study contributes to the literature by correlating water and energy parameters in the study of water distribution losses, having revealed the monetary values ​​of the losses and their impacts on society.

Improving the Efficiency of Submersible Multistage Pumps Based on the Hydrophobization of the Flow Part Surfaces

The paper presents an experimental study of an assembly of five stages of an electric centrifugal pump (ECP) installation, the flow part of which is modified according to the principles of biomimetics, namely using the “lotus leaf effect”. The object of the study was a 5A-35 ECP. The surfaces of the blade systems of impellers and guide devices of stages 5 A-35 were hydrophobized using the method of applying surfactant layers. The degree of impellers hydrophobicity was estimated by the wetting angle average value measured by three drops at three different points on the impeller surface. The impellers surface roughness under study was determined by the arithmetic mean profile deviation Ra and the profile height irregularities Rz. The issues related to the surfactant coating modification effect salt deposition and corrosion were studied. For this purpose, the surfaces of the original and modified impellers were subjected to intensive forced salt deposition as a result of prolonged exposure to saline solution. The conclusion about the samples corrosion resistance degree was made by changing their mass, which was due to the salt deposits formation during 15 hours of stay in solution, as well as using the drop method. Both methods have shown that the surfactant coating can serve as a salt deposition inhibitor, and the pump impeller modified by it has increased corrosion resistance. Thus, during comparative tests, a smaller mass of salt was deposited on the modified impeller sample during 15 hours of exposure in saturated saline solution than on the original sample. This indicates that the surfactant layer prevents the salt deposits fixation on the working surfaces of the pump stage. On the modified sample examined by the drop method, the indicator color changed in 20 minutes, and on the original one – in 2 minutes. Experimental studies have been carried out, during which the operation energy parameters of a five stages 5A-35 pumping package with initial and modified surfactant-coated impellers have been determined. The studies have shown a 2 % increase in efficiency in the pum-ping package of stages with modified impellers. The results of the study can be useful in the oil production, chemical industry, as well as in the housing and communal services sector.

Entropy generation in Casson nanofluid flow over a lubricated wall in the presence of induced magnetic field and activation energy

ABSTRACT The research on entropy generation in a mechanical system is quite imperative owing to its immense applications in the production of advanced cooling devices and medical appliances. The basic need on this research is how to optimize the irreversibilities within the systems and channelize that energy towards the benefit. This study elucidates the entropy generation analysis of a Casson nanofluid near a stagnation point over a lubricated vertical wall. A thin film of shear-thinning liquid with power law index of 0.5 is employed on the wall to ensure the lubrication. The effect of induced magnetic field and the chemical reaction stimulated by the activation energy is also incorporated within the flow. The non-linear PDEs of the substantive problem along with the compatible interfacial and boundary conditions are reverted into ODEs with the aid of suitable similarity transformation, and then cracked numerically using the sixth-order Runge Kutta method assisted with Nachtsheim–Swigert shooting practice. One of the significant findings reveals that the fluid friction irreversibilities in the entropy generation are diminished with the magnetic parameter and the Casson parameter, whereas the thermal irreversibility predominates over the total entropy generation for the escalating values of the activation energy parameter.

Nanocrystalization effects on the structural, electrical and thermoelectric properties of 10KNbO3-10Fe2O3-50B2O3-30V2O5 glass for non-volatile electronic-memory devices

AbstractThe composition: 10KNbO3-10Fe2O3-50B2O3-30V2O5 (in mol%) is produced using the conventional melt quenching method and their corresponding glass–ceramic nanocomposites were studied. The structural properties of the as-quenched sample and its heat-treated samples were investigated using X-ray diffraction and differential thermal analysis. Density (ρ) was found to decrease with increasing average nanocrystallite size as the molar volume increases. Studies on thermoelectric power have been carried out. The glass–ceramic nanocomposite after 2 h of heating exhibits significant improvement of electrical conductivity. The activation energy (W), polaron radius (rp) and other parameters have been estimated in the non-adiabatic region. The current–voltage (I–V) curve of each sample was measured. A temporal analysis of current & voltage in nonlinear I–V curves show pinched hysteresis loop, which is the memristor’s fingerprint. The glass–ceramic nanocomposite after 2 h of heating exhibits a large switching window. The results of the study enable us to predict that they will be helpful for future applications of non-volatile electronic-memory devices.

Significance of magnetic field and Darcy–Forchheimer law on dynamics of non-Newtonian hybrid nanofluid flow over a spinning disc with Arrhenius activation energy and shape factor

Purpose The purpose of the study is to explore the three-dimensional heat and mass transport dynamics of the magneto-hydrodynamic non-Newtonian (Casson fluid) hybrid nanofluid flow comprised of − as nanoparticles suspended in base liquid water as it passes through a flexible spinning disc. The influence of a magnetic field, rotation parameter, porosity, Darcy−Forchheimer, Arrhenius’s activation energy, chemical reaction, Schmidt number and nanoparticle shape effects are substantial physical features of the investigation. Furthermore, the influence of hybrid nanofluid on Brownian motion and thermophoresis features has been represented using the Buongiorno model. The novelty of the work is intended to contribute to a better understanding of Casson non-Newtonian fluid boundary layer flow. Design/methodology/approach The governing mathematical equations that explain the flow and heat and mass transport phenomena for fluid domains include the Navier−Stokes equation, the thermal energy equation and the solutal concentration equations. The governing equations are expressed as partial differential equations, which are then converted into a suitable set of non-linear ordinary differential equations by using the necessary similarity variables. The ordinary differential equations are computed by combining the shooting operation with the three-stage Lobatto BVP4c technique. Findings Graphs and tables are used in the process of analysing the characteristics of velocity distributions, temperature profiles and solutal curves at varying values of the parameters, along with friction drag, heat transfer rate and Sherwood number. It has been revealed that the radial and axial velocities decrease when the Casson parameter value increases and that the rate of heat transmission is higher in hybrid nanofluids with nanoparticles in the shape of a blade. The increase in Brownian motion and thermophoresis parameters causes a rise in the temperature profile. Also, an increase in the activation energy parameter improves the solutal curve. The use of nanoparticles was shown to improve extrusion properties, the rotary heat process and biofuel generation. Originality/value All results are presented graphically and all physical quantities are computed and tabulated. The current results are compared to previous investigations and found to agree significantly with them.