Calculation Of Parameters Research Articles

Application of artificial intelligence in mine ventilation: a brief review.

In recent years, there has been a notable integration of artificial intelligence (AI) technologies into mine ventilation systems. A mine ventilation network presents a complex system with numerous interconnected processes, some of which pose challenges for deterministic simulation methods. The utilization of machine learning techniques and evolutionary algorithms offers a promising avenue to address these complexities, resulting in enhanced monitoring and control of air parameter distribution within the ventilation network. These methods facilitate the timely identification of resistance faults and enable prompt calculation of ventilation parameters during emergency scenarios, such as underground explosions and fires. Furthermore, evolutionary algorithms play a crucial role in the advancement of methods for visual analysis of ventilation systems. However, it is essential to acknowledge that the current utilization of AI technologies in mine ventilation is limited and does not encompass the full spectrum of challenging-to-formalize problems. Promising areas for AI application include analyzing changes in air distribution caused by unaccounted thermal draft and gas pressure, as well as developing novel approaches for calculating shock losses. Moreover, the application of AI technologies in optimizing large-scale mine ventilation networks remains an unresolved issue. Addressing these challenges holds significant potential for enhancing safety and efficiency in mine ventilation systems.

Calculation of technological parameters during constrained extrusion of unequal channels. Definition of extrusion steps and general parameters

The calculation of technological parameters of constrained extrusion of channels from non-hardening and hardening materials under plane strain with a non-coaxial arrangement of the punch and matrix is considered. The resulting analytical expressions make it possible to determine the total and specific deforming forces and the heights of the resulting walls. Keywords:die forging, extrusion, misaligned arrangement, punch, matrix, plane strain, hardening mt13@bmstu.ru

A Simplified Approach for Calculating Heat Transfer Coefficients for Fluid Guiding Elements with Alternating Redirections of Flow

AbstractFluid guiding elements (FGEs), additive manufactured inserts that enhance heat transfer, have shown the potential to reduce the size of pipe‐in‐pipe heat exchangers up to a factor of 20. Due to their unique design, the calculation of the geometrical parameters for a specific application remains challenging and was initially solved by computationally expensive computational fluid dynamics simulations. This work presents a simplified approach, which treats the fluid and the FGE as pseudo‐homogeneous to enable the fast calculation of effective heat transfer coefficients. The approach is developed based on water in laminar flow state and subsequently tested with different fluids.

Morphological analysis of ballast particles: Characterization and simplified analysis of particle morphology using imaging data

This paper introduces a novel algorithm for the rigorous characterization of three-dimensional (3D) particles, particularly for railway ballast. Degraded railway ballast must be replaced with fresh material for efficient functioning. This study examined the shape and form of degraded (used) ballast to guide future maintenance efforts. Laboratory-generated used ballast, obtained via the Los Angeles abrasion test, was compared to fresh ballast. Thirteen fundamental morphological parameters of fresh and used ballasts were investigated by utilizing the shape information obtained through 3D scanning. The algorithm efficiently processed datasets comprising multiple irregular particles and monitored the morphological characteristics of ballasts based on the shape of the particles. The trimesh library was imported for 3D processing, facilitating the mathematical calculation of diverse parameters using the developed algorithm. The algorithm also incorporated mechanisms for simultaneously storing parameters provided in various 3D configuration models. With the support of the trimesh library, a morphology analyzer was used to analyze various 3D model file formats, such as .stl, .obj, and csg. This method demonstrated its efficacy with reduced runtime and computation cost. Thus, the proposed algorithm has emerged as a valuable resource for researchers investigating the influence of ballast particle shape on the mechanical behavior of granular assemblies.

Miner pose detection algorithm based on improved YOLOv7 in the coal mine

The unsafe behavior of workers in underground mines is a major cause of accidents. Recently, deep learning technology has become more and more widely used in the computer field and has achieved remarkable results, providing new opportunities for the research of miner behavior recognition algorithms. To address the current problem of large computation volume and low detection efficiency of multi-person posture detection in underground mines, we propose an improved algorithm that introduces the GSConv convolution module into the YOLOv7-Pose model and replaces the ELEN-W module with the GSELEN module to accelerate model convergence. We also introduce a group-convolution reconstruction SPPCSPC module to reduce parameter load and calculation amount and reduce the original 17 joint points to 14 joints to further realize a lightweight model. The experimental results showed that the improved YOLOv7-Pose model in this study decreased to 135.7 MB, by about 18.8%, while maintaining model accuracy. Therefore, this improvement can achieve a lightweight algorithm and improve real-time posture detection of construction workers in underground mines while ensuring model accuracy.

Optimization Design of Mechanical Properties of Frame Plate Structure for Aircraft Repair Based on Genetic Algorithm

Designing options for aircraft frame plate repair often relies on experience. Development of optimization technique is necessary to obtain optimal design for aircraft frame plate structure. In this paper, a method to optimize the repair parameters using genetic algorithm is proposed for the structural repair of aircraft frame plate. In the design process, the parameters of the reinforced piece are considered, including the type, length, width, thickness, and the layout of the rivets. Compared with the traditional genetic algorithm, the algorithm based on this paper considers the crossover between species and so on, so it can find the optimal solution in a wider design space. The finite element software ABAQUS combined with Python tool is used for parametric modelling and calculation, and the residual stress values of the repaired part is used as the objective function. Finally, a repaired aircraft frame plate structure with best static and dynamic properties is obtained.

Synthesis, characterization, thermal, theoretical studies, antimicrobial, antioxidant activity, superoxide dismutase-like activity and catalase mimetics of metal(II) complexes derived from sugar and Schiff base

Abstract Scientists are searching for reactive oxygen species, which have been associated with various health issues like heart problems, neurological disorders, inflammation, and aging. Salen complexes have proven to be effective in multiple oxidative stress situations and have been used as catalase and superoxide mimetics. To explore this further, three mixed complexes were synthesized using a Schiff base (salen) and a sugar (d-glucose) with Co(II), Ni(II), and Cu(II) ions. These complexes were then diagnosed by different analytical and spectral techniques. Stoichiometry, stereochemistry, some physical properties, and the method of bonding complexes were measured. Comparisons of the IR and 1HNMR spectra of the ligands with the complexes demonstrated the involvement of the azomethine group of the ligand in the chelation process. The mass spectra and TGA agree with the proposed formula of the complexes, and the conductivity and UV–Vis data supported the octahedral geometry of the complexes, and information was obtained from partial parameter calculations by molecular modeling. The metal complexes exhibited strong antimicrobial and antioxidant properties when compared to standard drugs. The like-superoxide and catalyst mimetic complexes were screened using DPPH ABTS, revealing their effectiveness.

Integrated design optimization of ducted lift fan for lift enhancement and noise reduction based on nested NFFD control body

In order to enhance the aerodynamic performance and reduce the aerodynamic noise of the coaxial dual-rotor ducted fan, this paper proposes a stepwise optimization strategy based on nested NFFD (Nurbs-Based Free-Form Deformations) control body parameterization. This strategy takes into account the optimization of aerodynamic performance, which involves significant deformations, and noise reduction, which requires fine deformations. By doing so, it effectively addresses the issue of drastically increased computational complexity and time consumption associated with conventional multi-objective optimization methods. By designing the aerodynamic shape of the blades, along with aerodynamic performance parameter calculation and aerodynamic noise calculation modules, it is possible to achieve lift enhancement and noise reduction for the ducted fan. The numerical simulation results demonstrate that the flow field over the optimized blade surface is improved significantly. The lift has increased from 3.45N to 3.54N, resulting in a 2.6% enhancement. Additionally, the noise level has decreased from 72.33dB to 69.52dB, achieving a noise reduction of 2.81dB.

Development of a Closed-Loop Controller for an Arduino-Based DC Chopper using Proteus and LabVIEW

This research focuses on developing a DC-DC converter voltage regulation system using an Arduino microcontroller, addressing the instability inherent in renewable energy sources like solar panels and wind turbines. Utilizing Proteus and LabVIEW, the study employs a quantitative deductive approach to experimentally simulate and model the system over four months at the Control and Automation Laboratory of Politeknik ATI Makassar. Key challenges of conventional converters, including limited PWM flexibility, output stability, and ripple reduction, are addressed through a closed-loop control system with voltage feedback. The methodology involves extensive parameter calculations derived from literature review and expected testing scenarios to ensure precise component selection and system performance. Specific calculations guide the determination of minimum component values, facilitating the desired input and output voltage levels with minimal ripple. Simulation testing validates the system's effectiveness, demonstrating successful integration between LabVIEW and Proteus through additional library utilization. The resulting DC-DC converter voltage regulation system enables more robust control through Arduino microcontroller, enhancing stability and efficiency in renewable energy applications.

Interactions at the interfaces of the H2-brine-cement systems at elevated pressures for H2 storage

There is a global demand on assessment of potential subsurface gas storage sites in view of safely injecting hydrogen or carbon dioxide. One relevant aspect that has already been subject to thorough investigation is the mutual interaction of all participating compounds in terms of the wetting behaviour that on its turn is directly related to the predominating capture mechanisms. Given the diversity of the geophysical and geochemical circumstances, transferability of results from work conducted on one geological site to another location is limited. For instance, there is a large number of publications on wettability of many different rock types in hydrogen atmosphere that are partly controversal and strictly applicable only to the respective reported system. Hence, there is a gap in finding general model approaches that serve for a holistic understanding of predominating mechanisms and building the fundamentals for predicting the behaviour of systems that have not been studied so far. The presented work addresses this gap by quantifying mutual interactions of the participating phases in a solid-liquid-gas systems and determining the respective interfacial tensions, γSV (solid-vapor), γLV, (liquid-vapor) and γSL (solid-liquid).Neumann and Good demonstrated how to determine the solid-fluid interfacial tension based on the contact angle and the liquid-gas interfacial tension by calculating a so-called molecular interaction parameter. Up to date, this method has been applied, among others, for systems containing CO2 and solids such a teflon, glass, and steel. The methodology could be confirmed by testing systems comprising steel - H2O - CH4 /H2 and comparing the results to the aforementioned literature data.As one of the critical parts in H2 underground storage, the completion system containing a common well cement, H2 and brine was subject to this work. The interfacial tension between H2 and brine as well as the contact angle between the fluid phases and the cement were investigated experimentally up to 20 MPa, temperatures from 313.15 to 353.15 K and NaCl – concentrations of up to 10% wt. As a theoretical approach, the interfacial tension of the system H2O+H2 was investigated using the density gradient theory (DGT) in combination with the perturbed chain statistical associating fluid theory equation of state (PC-SAFT). Finally, the H2-cement interfacial tension is determined through the calculation of a so-called molecular interaction parameter. The interfacial tension data of H2O+H2 experimentally and theoretically determined in this work agree among each other as well as with previous literature data. Likewise, agreement was found between the brine+H2 interfacial tension and previous studies. The contact angle appears to be influenced mostly by pressure, producing a less H2O/brine-wet system as pressure increases. The H2-cement interfacial tension decreases from approximately 150 mN/m down to 100 mN/m, as the pressure increases from 0.1 to 20 MPa. The presented data suggest H2 to be slightly adsorbed on the one hand but the capillary entry pressure to decrease on the other, causing concerns regarding the integrity of the completion system.

Structural elucidation of ternary mixtures of L‐valine/glycyl‐L‐valine and water + 1‐decyl‐3‐methylimidazolium bromide: Apparent molar properties at infinite dilution and expansivities

AbstractThis work comprises ternary systems of water + SAIL,1‐decyl‐3‐methylimidazolium bromide, and (S)‐2‐Amino‐3‐methylbutanoic acid generally identified as L‐valine/ (S)‐2‐(2‐Aminoacetamido)‐3‐methylbutanoic acid usually described as glycyl‐L‐valine, densities, and sound speed data have been computed at four operating temperatures, i.e., 288.15 to 318.15 K. Calculated density data have utilized for calculation of various thermodynamic parameters like Vϕ (apparent molar volume), (apparent molar volumes at infinite dilution), and calculated speed of sound statistics used to determine Kϕ,s (apparent molar isentropic compression), Ks (partial molar isentropic compression at infinite dilution). In our systems, the hydrophilic‐ionic interactions that are produced by co‐sphere overlap models are predominant. The Hepler's constant is used to analyze the solute's capacity to create or destroy solvent structures. The interaction parameter is computed using the McMillan‐Mayer theory. Understanding structure‐making, solvation characteristics, and numerous modifications in the ternary system of L‐valine/Glycyl‐L‐valine, water, and [C10MIm] [Br] is aided by a variety of thermodynamic factors.

The need for universal program tool for automation of calculation of mining parameters

The need for universal program tool for automation of calculation of mining parameters

Experimental study on the mechanical property of carbon fiber reinforced polymer with the combined application of digital twin and reduced order algorithm

AbstractRecognizing the anisotropy of mechanical property transfer between carbon fiber reinforced polymer (CFRP) layers, a unidirectional reduced‐order model (UROM) is proposed to comprehensively express the mechanical properties of each layer. A crucial focus is on effectively analyzing the real‐time mechanical properties of CFRP specimens, particularly in accurately identifying and predicting the interlaminar mechanical states of anisotropic CFRP laminated specimens. Moreover, the multi fidelity surrogate (MFS) is employed to replace the computationally intensive model, amalgamating high‐fidelity sensor data with low‐fidelity data obtained from the UROM. The UROM MFS is used to reduce the amount of data in the same layer of CFRP laminates, while preserving the characteristics between different layers and preserving the interlaminar information of CFRP laminates. Finally, the stress prediction results of the UROM MFS and the unreduced MFS model were compared and analyzed. The real‐time response speed of the u‐ROM MFS digital twin (DT) model was increased by 658%. The UROM MFS DT model effectively captures the mechanical properties of each layer of CFRP laminates, enables quick calculation of model parameters, and provides accurate predictions.Highlights First, the interlayer mechanical property of CFRP is analyzed with the combined application of experimental data, DT model, and UROM MFS. Second, MFS is employed to merge high‐fidelity sensor data of CFPR laminate with low‐fidelity data obtained from UROM. Third, the digital twin framework for CFPR laminate with high response speed and calculation accuracy is proposed.

A new computationally efficient algorithm to generate global fractional vegetation cover from Sentinel-2 imagery at 10 m resolution

ABSTRACT The multi-angle method in the pixel dichotomy model (PDM) is used to produce fine spatial resolution (FSR) products of fractional vegetation cover (FVC), which involves numerous iterative computations. This phenomenon causes a low computational efficiency for global FVC. Here, we established the multi-angle equations, and simplified the two-stream approximation method to obtain multi-angle reflectance, which calculated the KDM parameters possible. Moreover, to accelerate the calculation of parameters in the multi-angle equations, land cover data were utilized as priority knowledge, which aims to decrease iterative computations to speed up the computational speed. Finally, we proposed an accelerated pixel dichotomy coupled linear kernel-driven model (PDKDM-A). By validating PDKDM-A using field measurements and FVC products, we found that the global FVC computed for various land covers exhibited strong agreement with the field measurements. The root mean square errors (RMSEs) were consistently below 0.150, except for grasslands, croplands, and cropland/natural vegetation mosaics. When comparing FVC products on the same scale, we discovered that the RMSE was less than 0.103, except for deciduous broadleaf forests. Our study demonstrates that PDKDM-A is an efficient algorithm, with the potential to quickly generate accurate global FVC products with fine spatial resolution.

Studying how changes in the structure caused by hydrogen bonding affect the corrosion resistance of polybenzoxazine-based coatings using molecular dynamics simulations

Polybenzoxazine (PBz) based coatings were prepared using designed PBz monomers for corrosion protection. The structure and properties of poly(MPM) and poly(POPM) coatings deriving from PBz monomer with methyl group and phenoxy group, respectively, were fully investigated by Fourier transform infrared spectroscopy, water contact angle measurements and electrochemical impedance spectroscopy. For the two crosslinking coating systems, the poly(POPM) coating, with a lower intermolecular hydrogen bonding ratio of 9.7 %, exhibited better hydrophobicity, stability, and corrosion resistance. This is evidenced by a water contact angle (WCA) exceeding 94° (90° for poly(MPM) system) and a charge-transfer resistance surpassing 1 GΩ cm2 (1 MΩ cm2 for poly(MPM) system) even after 30 days of immersion in a 3.5 wt% NaCl solution. The distinct performance in corrosion resistance performance between the two systems can be attributed to structural changes arising from hydrogen bonding, which were extensively investigated through solubility parameters calculation and molecular dynamics simulations in this study. The results show that the prevalence of intra‑hydrogen bonding in the poly(POPM) coating lead to a more compact structure and enhanced hydrophobicity against water, thereby enhancing the barrier ability of PBz based coatings against the penetration of corrosive substances.

Reducing plug flow effect on measured rheological results of cement-based materials: Image analysis and numerical iteration approach

The rheological properties of cement-based materials (CBM) significantly influence their workability and application in construction. Despite the common use of coaxial cylinder rheometers for measuring these properties, challenges arise, particularly at low shear rates due to plug flow within the tested samples. This study aims to investigate the impact of plug flow on rheological property measurements of CBM and proposes strategies to enhance measurement accuracy. An image analysis method and a novel numerical iteration algorithm were proposed in this study to address plug flow effects. Three series fresh cement paste with different fluidities were prepared to conduct the rheological tests. Through the image analysis method, actual shear radii at different rotor speeds were measured. The corresponding rheological parameters were determined and compared using the complete shear assumption, the image analysis method, and numerical iteration algorithm, respectively. The results indicated the great influence of plug flow on rheological results, especially at low shear rates and low fluidities, highlighting the need for its consideration in rheological parameters calculations. Moreover, the proposed numerical iteration algorithm was verified to calculate the incomplete shear state of CBM and improve the measurement accuracy of rheological parameters. The extensions and limitations of the numerical iteration algorithm in its application were discussed further.

Investigations on the defect structures for Mn2+ in CdSe nanocrystals and bulk materials and the criterion of occupation for Mn2+ in CdX (X = S, Se, Te) nanocrystals.

The spin Hamiltonian parameters and defect structures are theoretically studied for the substitutional Mn2+ at the core of CdSe nanocrystals and in the bulk materials from the perturbation calculations of spin Hamiltonian parameters for trigonal tetrahedral 3d5 clusters. Both the crystal-field and charge transfer contributions are taken into account in the calculations from the cluster approach. The impurity-ligand bond angles are found to be about 1.84° larger and 0.10° smaller in the CdSe:Mn2+ nanocrystals and bulk materials, respectively, than those (≈109.37°) of the host Cd2+ sites. The quantitative criterion of occupation (at the core or surface) for Mn2+ in CdX (X = S, Se, Te) nanocrystals is presented for the first time based on the inequations of hyperfine structure constants (HSCs). This criterion is well supported by the experimental HSCs data of Mn2+ in CdX nanocrystals. The previous assignments of signals SI as Mn2+ at the core of CdS nanocrystals are renewed as Mn2+ at the surface based on the above criterion. The present studies would be helpful to achieve convenient determination of occupation for Mn2+ impurities in CdX semiconductor nanocrystals by means of spectral (e.g., HSCs) analysis.

Measurement, correlation and thermodynamic analysis of the solubility of dicyandiamide in three binary solvents

Dicyandiamide (DCD) is an important chemical raw material. The solid–liquid equilibrium solubility of DCD in three kinds of binary solvent mixtures (N,N-dimethylformamide (DMF) + ethanol, DMF + acetonitrile, DMF + acetone) at T = (283.15–323.15) K was determined by gravimetric method. The thermodynamic parameters of DCD dissolution in solvents were studied. The solubility of DCD in the three groups of binary mixed solvents increases with the increase of temperature. In three binary mixed solvents, the solubility of DCD increases monotonically with the increase of DMF composition. The modified Apelblat model, van’t Hoff model, λh model, the nonrandom two-liquid (NRTL) model and the Apelblat-Jouyban-Acree model were used to correlate the solubility data. The results show that the modified Apelblat model have the best correlation with the solubility of DCD. The calculation of thermodynamic parameters during the dissolution process indicates that dissolution is exothermic and driven by both enthalpy and entropy. This work can provide reference for improving the crystallization process of DCD, as well as for improving the chemical production process using DCD as raw material.

Spectroscopy of the 5s5p3P0→5s5d3D1 transition of strontium using laser cooled atoms

This article presents spectroscopy results of the 5s5p3P0→5s5d3D1 transition in all isotopes of laser cooled Sr atoms and the utility of this transition for repumping application. By employing the 5s5p3P0→5s5d3D1 (483 nm) transition in combination with the excitation of 5s5p3P2→5s6s3S1 (707 nm) transition, we observe a significant increase (∼13 fold) in the steady state number of atoms in the magneto-optic trap. This enhancement is attributed to the efficient repumping of Sr atoms that have decayed into the dark 5s5p3P2 state by returning them to the ground state 5s21S0 without any loss into the other states. The absolute transition frequencies were measured with an absolute accuracy of 30 MHz. To support our measurements, we performed Fock-space relativistic coupled-cluster calculations of the relevant parameters in Sr To further increase the accuracy of the calculated properties, corrections from the Breit, quantum electrodynamical and perturbative triples were also included. The calculated branching ratio for the repumping state confirms the significantly increased population in the 3P1 state. Thereby, leading to an increase of population of atoms trapped due to the enhanced repumping. Our calculated hyperfine-splitting energies are in excellent agreement with the measured values. Moreover, our calculated isotope shifts in the transition frequencies are in good agreement with our measured values.

Towards white light emission in Dy3+/Sm3+ co-doped niobio silicate glasses via adjusting doping concentration and excitation wavelength for w-LED applications

The commercial LED has the disadvantages of low thermal stability and poor luminous quality at high temperature due to the organic resin encapsulation phosphor, and luminous glass is one of the effective ways to solve this problem. A series of niobium silicate (SiO2–Nb2O5–Na2O–K2O–Dy2O3–Sm2O3, labeled as SNNKDS) luminous glasses have been obtained by melt quenching method. The results of differential thermal analysis prove the existence of high thermal stability. The infrared spectrum, Raman spectrum and the calculation of physical parameters reveal the excellent thermal stability and stable structure of the prepared glass. The optical properties of luminescent glass have been studied in detail, the energy transfer from Dy3+ ions to Sm3+ ions has been observed, the Dy3+/Sm3+ co-doping glasses can achieve warm white light emission by changing the excitation wavelength and the doping amount of Sm3+. The variable temperature emission spectrum of SNNK:0.8D0.4 S is analyzed. At 423 K, the comprehensive emission intensity is 79.91 % of that at room temperature, the ΔC value of colorimetric shift at 473 K is 2.1 × 10−2. The warm white light output with excellent correlated color temperature (3746 K) has been achieved using glass samples encapsulated with 395 nm LED chip. The analysis shows that Dy3+/Sm3+ co-doped niobium silicate glasses can be regarded as a candidate for the w-LED applications.