Computational Experimental Methods Research Articles

EvoAI enables extreme compression and reconstruction of the protein sequence space.

Designing proteins with improved functions requires a deep understanding of how sequence and function are related, a vast space that is hard to explore. The ability to efficiently compress this space by identifying functionally important features is extremely valuable. Here we establish a method called EvoScan to comprehensively segment and scan the high-fitness sequence space to obtain anchor points that capture its essential features, especially in high dimensions. Our approach is compatible with any biomolecular function that can be coupled to a transcriptional output. We then develop deep learning and large language models to accurately reconstruct the space from these anchors, allowing computational prediction of novel, highly fit sequences without prior homology-derived or structural information. We apply this hybrid experimental-computational method, which we call EvoAI, to a repressor protein and find that only 82 anchors are sufficient to compress the high-fitness sequence space with a compression ratio of 1048. The extreme compressibility of the space informs both applied biomolecular design and understanding of natural evolution.

Harnessing the Strengths of Computational Advertising and Experimental Methods to Enhance Research Design

Computational methods such as those used in computational advertising research are often considered at odds with experimental methods. This divergent view of these two paths has frequently led to researchers examining these methodologies in isolation. In this article, we take the view that each path has value and that the strengths of one can inform the other. To this end, we provide a guide to conducting research that focuses on four strengths inherent to experimental research—the principle of control, random assignment of treatments, the exploration of underlying mechanisms, and transparency—that can provide lessons to those using computational advertising data. Similarly, we focus on three strengths inherent to computational advertising research—the collection of behavioral data, the realistic nature in which the data are obtained, and the ability to study dynamic changes over time—that can provide lessons on how to enhance experimental research. In doing so, we assist researchers in strengthening their study designs regardless of their preferred methodology.

Study on electrochemical anodization initiation and progression of binderless tungsten carbide (WC) through experimentation and simulation

This article explores the electrochemical anodization of binderless tungsten carbide (WC) using computational simulations and experimental methods. It aims to comprehend the complex relationship between anodization time, surface roughness, elemental composition, and current behavior on polished and non-polished substrates. COMSOL Multiphysics models provide the initial findings by meticulously mapping the electrolyte's potential and the current density vectors. These simulations reveal the fundamental electrochemical behaviors anticipated during anodization, particularly emphasizing the regions near the anode expected to undergo anodization. Experimental observations confirm the simulation results, showcasing how non-polished WC surfaces, replete with inherent imperfections, undergo anodization characterized by fluctuating current densities and compositional changes, highlighting the profound influence of surface defects on electrochemical processes. On the other hand, when WC substrates are polished, they show a more consistent and controlled anodization process. This suggests a close connection between the occurrence of anodization and the surface treatment, ultimately influencing the effectiveness of anodization. This comprehensive study, which combines simulation and experimentation, greatly enhances the understanding of the electrochemical anodization of WC. It suggests potential methods for enhancing surface modifications to expand the range of applications for WC, particularly in precision glass molding, aerospace, and medical industries.

Structure design and mechanism research of combined cyclone plate separator based on particle separation

Although there has been much research on the gas–solid separation equipment of cyclone plate, there is still a lot of research space for miniaturization, low resistance, and easy maintenance. In this paper, parallel gas–solid separation equipment is designed based on computational fluid dynamics and experimental verification methods to address the practical problems faced by the fresh air system of the enterprise plant. The internal flow field of the separator is studied by numerical simulation, and the structural parameters of the separator are optimized according to the performance indicators provided by the enterprise. The optimal structure that meets the performance requirements and has the best effect is determined. Subsequently, the actual performance of the optimal structure was verified by wind tunnel experiments, and the deviation between the experimental results and the numerical simulation results was compared. The results show that increasing the number of blades, adjusting the blade angle, and increasing the height of the outer cylinder are beneficial in improving the internal flow field of the separator. Among them, the blade angle significantly affects the tangential velocity and axial velocity of the separator. When these three parameters are increased, the filtration efficiency increases first and then decreases. Finally, when the number of blades is 8, the blade angle is 50°, and the height of the outer cylinder is 0.63 m, the separation efficiency is the highest, and the pressure drop is the lowest. This structure satisfies all performance indicators. The experimental results show that the minimum filtration efficiency is 92.4%, and the maximum pressure drop does not exceed 500 Pa. Compared with the numerical simulation results, the experimental value is 0.29% lower, which shows that the structure has good separation performance and has a significant reference value for the fresh air system of the industrial workshop.

Expression Pattern of RpCSP6 from Rhopalosiphum padi and Its Binding Mechanism with Deltamethrin: Insights into Chemosensory Protein-Mediated Insecticide Resistance.

The mechanisms of insecticide resistance are complex. Recent studies have revealed a novel mechanism involving the chemosensory system in insecticide resistance. However, the specific binding mechanism between olfactory-related genes and insecticides needs to be clarified. In this study, the binding mechanism between pyrethroid insecticide deltamethrin and RpCSP6 from Rhopalosiphum padi was investigated by using computational and multiple experimental methods. RpCSP6 was expressed in different tissues and developmental stages of R. padi and can be induced by deltamethrin. Knockdown of RpCSP6 significantly increased the susceptibility of R. padi to deltamethrin. The binding affinity of RpCSP6 to 24 commonly used insecticides was measured. Seven key residues were found to steadily interact with deltamethrin, indicating their significance in the binding affinity to the insecticide. Our research provided insights for effectively analyzing the binding mechanism of insect CSPs with insecticides, facilitating the development of new and effective insecticides that target insect CSPs.

Flow field analysis and performance evaluation of a mini-hydrocyclone for ultra-low inlet flow rate

It is difficult for hydrocyclone to separate oil-water under the condition of ultra-low inlet flow rate, which commonly exist in the field of energy engineering. Mini-hydrocyclone is an effective technology to solve this problem. The flow field characteristics and oil droplet migration trajectory in the mini-hydrocyclone are the key to guide its efficient work. An innovative mini-hydrocyclone are studied via computational fluid dynamics (CFD) and experiment method. The good separation performance of mini-hydrocyclone for ultra-low inlet flow rate and tiny particle size of oil droplets is verified and analyzed. Furthermore, The distribution of velocity, oil volume fraction and oil migration trajectories in the mini-hydrocyclone are analyzed systematically. The effects of oil droplet size, inlet flow rate and split ratio on the separation performance of mini-hydrocyclone are investigated. The results show that the maximum separation efficiency of the mini-hydrocyclone for 1.0 L/min ultra-low inlet flow rate is 99.98 %, when the split ratio is 30 %, the oil phase volume fraction is 2 %. Moreover, the morphological and distribution of oil core in mini-hydrocyclone are basically consistent between simulation and experiment results, under the conditions of different operating parameters. The minimum error of numerical simulation and experiment results is less than 2.23 %, the accuracy of the numerical simulation method is verified.

The Limited Incorporation and Role of Fluorine in Mn-rich Disordered Rocksalt Cathodes.

Disordered rocksalt oxide (DRX) cathodes are promising candidates for next-generation Co- and Ni-free Li-ion batteries. While fluorine substitution for oxygen has been explored as an avenue to enhance their performance, the amount of fluorine incorporated into the DRX structure is particularly challenging to quantify and impedes our ability to relate fluorination to electrochemical performance. Herein, an experimental-computational method combining 7Li and 19F solid-state nuclear magnetic resonance, and ab initio cluster expansion Monte Carlo simulations, is developed to determine the composition of DRX oxyfluorides. Using this method, the synthesis of Mn- and Ti-containing DRX via standard high temperature sintering and microwave heating is optimized. Further, the upper fluorination limit attainable using each of these two synthesis routes is established for various Mn-rich DRX compounds. A comparison of their electrochemical performance reveals that the capacity and capacity retention mostly depend on the Mn content, while fluorination plays a secondary role.

Machine Learning Orchestrating the Materials Discovery and Performance Optimization of Redox Flow Battery

AbstractThis review exploits the crucial role of computational methods in discovering and optimizing materials for redox flow batteries (RFBs). Integration of high‐throughput computational screening (HTCS) and machine learning (ML) accelerates materials discovery, guided by algorithms categorizing RFBs. A collaborative exploration, spanning macroscopic to mesoscopic scales, combines quantum machine learning with reinforcement learning, transfer learning, time series analysis, Bayesian optimization, active learning and various generative models. The collaborative integration of ML with computational techniques and experimental methods, anchored in experimentally validated Density Functional Theory (DFT) calculations and molecular dynamics (MD) simulations, proves indispensable for cost‐effective RFBs. Data collection and feature engineering are explored, emphasizing the integration of optimization goals and precise data collection within the ML framework. Feature analysis importance is highlighted, utilizing methods such as the filter, embedded, wrapper and deep learning methods for efficient energy materials exploration. Computational perspectives on materials features and operating conditions encompass membrane characteristics, fluid dynamics, temperature dependence and pressure sensitivity. Time‐dependent features and ML‐generated insights are crucial for understanding cycling performance intricacies, providing a comprehensive understanding of RFB materials.

Evaluation of the efficiency of energy complexes with the production of hydrogen, oxygen, heat and electricity

RELEVANCE of the research. The global trend of decarbonization of the national economies of the leading countries of the world implies an increase in energy production due to renewable energy sources and hydrogen. The most environmentally friendly way to produce hydrogen is the electrolysis of water using wind and solar energy. Combined production of thermal, electric energy, hydrogen and oxygen carried out by energy complexes ensures reduction of harmful emissions and increase of their economic efficiency.METHODS. In solving this problem, the method of computational experiment was used, taking into account the geographical and climatic data of the location of the energy complex, as well as the nature of consumption of thermal, electric energy and hydrogen. The calculation was implemented in Visual Basic.RESULTS. The article describes the relevance of the topic, examines the influence of the installed capacity of photovoltaic converters, geographical, climatic and cost characteristics on the efficiency of the energy complex.CONCLUSION. The structure is determined and a schematic diagram of a multi-purpose energy complex is proposed. A methodology for calculating quantitative and economic indicators of the installation has been developed. In the course of the study, it was noted that there is an optimal value of the installed capacity of a photovoltaic installation, further increase of which is inexpedient from an economic point of view. It was also determined that the combination of hydrogen gas stations based on solar installations with traditional sources of energy supply can reduce the cost of hydrogen produced, which in the future may be a solution to the problem of creating a hydrogen infrastructure.

Thermal-hydraulic performance of modified Schwartz-Diamond solid-networks triply periodic minimal surface structures

The triply periodic minimal surface (TPMS) structures are widely used as disturbance core structure in high performance heat exchangers. In this paper, four modified Schwartz-Diamond solid-networks (SD-solid) TPMS structures, one structure compressed along the flow direction (β = 2), and three structures compressed along the spanwise direction (α = 2, α = 3, and α = 4) are designed. Flow and heat transfer processes in the structures are studied with computational fluid dynamics (CFD) and experimental method. The performance enhancement criterion (PEC) is employed to evaluate the overall heat transfer performance. As the results of simulation, the overall heat transfer coefficient (hoverall) of α = 2, α = 3, and α = 4 is 10.04 %, 34.34 %, and 62.03 % higher than that of SD-solid respectively. The PEC of α = 2, α = 3, and α = 4 structures is 27.35 %, 34.17 %, and 34.95 % higher than that of the original SD-solid structure, respectively. Two samples of them (β = 2 and α = 2) are fabricated using additive manufacturing and their thermal–hydraulic performance is experimented on a flow and heat transfer experimental platform. Comparing the experimental results of the hoverall, the β = 2 structure is 68.5 % higher and the α = 2 structure is 23.06 % higher than the original SD-solid structure. However, for the average pressure drop, the β = 2 structure is 448.5 % higher and the α = 2 structure is 66.77 % lower than the original SD-solid structure. It is proved that the modified SD-solid structure compressed along the spanwise direction has the performance of enhancing heat transfer and reducing the pressure drop.

Constructions of statistical estimates of digital measurement error in the case of small samples

The paper presents a computational-experimental method for the construction of statistical estimates of the error of digital measurements carried out on complex technical objects with metrological support. The algorithm of construction of the estimation of the distribution density function of random error of measurements on the basis of complex application of methods of the theory of characteristic functions, the theory of Lie operator series and methods of statistical modeling in the processing of a limited amount of statistical information in the conditions of small samples is described. The solution of the practical problem on the construction of the estimation of the measurement error distribution density and the problem on the zero mark of the measuring instrument in the probabilistic formulation is given. The presented computational and experimental method can be used to construct statistical estimates for the probability distribution density of the general type, including those given by implicit functions, characteristic functions and operator series.

Influence of stationary porous media on fluid flow

The work examines the flow of an incompressible fluid containing a porous medium. A porous body is formed through various mechanisms. To describe the flow, a single equation is used that describes the flow of fluid in the porous and free zone. The flow is simulated based on Rakhmatulin’s two-speed model, in a laminar mode with zero speed of a discrete phase. The results of numerical simulation of the hydrodynamic features of a two-dimensional viscous flow are presented. The Kozeny-Karman relation is used as the force of interaction with the porous layer. Computational experimental methods are used to study the effects of nonuniformity of the fluid velocity field arising from a porous body. For the numerical implementation of the resulting equation, which is a generalization of the Navier-Stokes equation, a SIMPLE-like algorithm with corresponding generalizations was used. A single algorithm is used for the entire area, without identifying the free and porous zones.

Advancing thermal management in electronics: a review of innovative heat sink designs and optimization techniques.

The ongoing trend towards miniaturizing electronic devices and increasing their power densities has created substantial challenges in managing the heat they produce. Traditional heat sink designs often fall short of meeting modern electronics' rigorous thermal management needs. As a result, researchers and engineers are turning to innovative heat sink designs and optimization methods to improve thermal performance. This review article offers an overview of the latest advancements in designing and optimising advanced heat sinks for electronic cooling. It explores various techniques to enhance heat transfer, including advanced surface geometries and microchannels. Additionally, the review covers computational fluid dynamics (CFD) modelling and experimental validation methods used to refine heat sink designs. Further insight into fouling and its prevention has been discussed. The insights provided in this article are intended to serve as a valuable resource for thermal engineers, and researchers focused on managing the heat in high-power electronic systems.

Tunable growth of a single high-density ZIF nanoshell on a gold nanoparticle isolated in an optical trap.

Here, we demonstrate an all-optical method using an optical tweezer to controllably grow high quality zeolitic imidazolate framework (ZIF) nanoshells on the surface of gold nanoparticles (AuNPs) and monitor the growth via darkfield spectroscopy. Our single particle approach allows us to localize an individual NP within a microscope slide chamber containing ZIF precursors at the focus of an optical microscope and initiate growth through localized heating without affecting the bulk system. Darkfield spectroscopy is used to characterize changes to the localized surface plasmon resonance (LSPR) of the AuNP resulting from refractive index changes as the ZIF crystal grows on the surface. We show that the procedure can be generalized to grow various types of ZIF crystals, such as ZIF-8, ZIF-11, and a previously undocumented ZIF variety. Utilizing both computational models and experimental methods, we identify the thickness of ZIF layers to be self-limiting to ∼50 nm or less, depending on the trapping laser power. Critically, the refractive index of the shells here was found to be above 1.6, indicating the formation of high-density crystals, previously accessible only through slow atomic layer deposition and not through a bulk heating process. The single particle method developed here opens the door for bottom-up controllable growth of custom nanostructures with tunable optical properties.

Simulation and Experimental Study of a Novel Negative-Pressure Flapper-Nozzle Mechanism.

As the manufacturing industry evolves, the significance of control valve positioners in chemical production escalates. The flapper-nozzle system, the heart of control valve positioners, directly influences the linearity of system control. Presently, studies on the flapper-nozzle system primarily focus on dynamic system modeling and computational fluid dynamics simulations. However, traditional flapper-nozzle mechanisms often fail to achieve linear control objectives. This paper proposes a novel negative-pressure nozzle structure to tackle this issue, combining computational fluid dynamics and experimental methods, and considering gas compressibility during high-speed flow. Both simulation and experimental results suggest that the new structure improves the supply air pressure and broadens the linear pressure output range of the system, showing significant potential for practical applications.

Mathematical modeling of autocompensation devices

The article is devoted to the order of development and description of mathematical models of automatic compensation devices of all-round radar stations. The development of algorithms for spatial processing of signals in radar systems with phased antenna arrays is an important stage in the design of radar stations. This article will consider the procedure for creating mathematical models of automatic compensation devices that differ in implementation methods, namely: the number of compensation channels, the position of the main and compensation (additional) channels of the radar station (stationary or dynamic), the amplitude-phase distribution of the main and additional antennas, the representation phased antenna array, algorithms for finding the weight vector. The adequacy of the operation of the models was verified by the method of computational experiment and the results are comparable with the implemented automatic compensation devices in radar stations. The results of the computational experiment, presented in the form of graphs of the signal at the output of the automatic compensation device, as well as the passage of the matched filter, show how effective the algorithm for calculating the weight vector, allow you to visually, quickly and economically compare the efficiency of the automatic compensation devices, depending on the method of their implementation. The article discusses the algorithm for the direct formation of the weight vector and the algorithm for the formation of the weight vector through the inverse correlation whitening matrix. Mathematical models of automatic compensation devices and the results of a computational experiment can be used to train future specialists who develop and operate radar stations.

Simulation and experimental study on flow and heat transfer performance of sheet-network and solid-network disturbance structures based on triply periodic minimal surface

Triply periodic minimal surface (TPMS) structures are widely used in the field of flow and heat transfer. In this paper, four TPMS structures, Schwartz Diamond-sheet (D-sheet), Schwartz Diamond-solid (D-solid), Schoen IWP-sheet (IWP-sheet), and Schoen IWP-solid (IWP-solid), are designed based on two structure generation strategies. The above structures all are manufactured through additive manufacturing, and the material is AlSi10Mg. The samples were characterized by X-ray scanning. The flow and heat transfer performance of different TPMS structures was studied by computational fluid dynamics (CFD) and experimental methods. The results show that the pressure drop of sheet-network is larger than that of solid-network for the same TPMS type. With the same structure generation strategy, the pressure drop of Schwartz Diamond (D-type) is greater than that of Schoen IWP (IWP-type). The heat transfer performance of the TPMS structure shows the same results as the pressure drop. The performance enhancement criterion (PEC) of the solid-network TPMS is better than that of the sheet-network structure, and the D-type TPMS structure is better than the IWP-type structure. The average PEC of D-solid and IWP-solid is 31 % and 44 % larger than that of D-sheet and IWP-sheet, respectively. The average PEC of D-sheet and D-solid is 11.8 % and 1.7 % larger than that of IWP-sheet and IWP-solid, respectively. The mechanism of the higher PEC of the solid-network structure is the low pressure drop caused by the high through-hole ratio and relatively concentrated skeleton. Under the same pressure drop, the heat transfer performance of TPMS with D-type sheet structure is better. The research content of the article is mainly applied to fin-enhancement, which can replace fins in traditional heat exchangers. In actual engineering applications, the TPMS structures type is reasonably selected according to the requirements.

SINGLE-FACTOR ANALYSIS OF VARIANCE ON THE EFFECT OF BLADE'S NUMBER ON ROTOR DRAG-TYPE PERFORMANCE

The State Electricity Company supports 59% of the national electricity supply in Indonesia. The electricity supply from hydro energy is only 8.17%, so this value must be increased to reduce the supply of power plants sourced from fossil fuels. A water turbine is one of the main components in converting hydropower to electrical energy. A cross-flow type water turbine is one of the popular rotors in research in recent years. Several methods are used in turbine development research, including computational fluid dynamics and experimental methods. This research has been done using two methods: the experimental and CFD methods. The study was conducted on variations in the number of blades on the rotor, with variations in blades 3, 4, 6, 8, 10, and 12. This study aims to determine the effect of the number of blades on turbine performance. This study was carried out for five repetitions for each rotor. CFD analysis was performed using the Ansys Student version with the CFX solver. The meshing method is tetrahedral, with a speed limit of 4.91 m/s and outlet pressure according to room pressure. This study uses CFD to know the pressure contours and velocity streamlines. The results of this study were analyzed using a single-factor DOE. The most optimal number of blades is 3-blades producing 9.38 Watt of power, and the Coefficient of power is 0.0748. Analysis of Variance for the Single-Factor shows that the number of blades significantly affects the energy produced. Cross-flow rotor design with 3-blades is a good design alternative for hydro turbines.

Influence of strong solar proton events on propagation of radio signals in the VLF range in a high-latitude region

In this paper, we examine the features of RSDN-20 signal propagation in a high-latitude Earth–ionosphere waveguide during solar proton events, using computational experiment methods. We have analyzed two proton ground-level enhancement (GLE) events of December 13, 2006 (GLE70) and September 10, 2017 (GLE72). Electron density profiles were constructed using the Global Dynamic Model of Ionosphere (GDMI) and the RUSCOSMICS model, developed at PGI. We present estimated phase and amplitude changes in RSDN-20 signals during precipitation of high-energy protons in the high-latitude region of the Earth–ionosphere waveguide. From the results of computational experiments and the analysis of the electromagnetic signal attenuation based on analytical Maxwell’s equation system solution in magnetized ionospheric plasma, we have found a pattern in the signal attenuation frequency dependence associated simultaneously with the signal reflection height, electron density profiles, and the collision frequency of electrons with neutral particles and ions. We discuss limitations of the computational experiment method and compare simulation results with data from Lovozero and Tuloma observatories.

Влияние сильных солнечных протонных событий на распространение радиосигналов в диапазоне ОНЧ в области высоких широт

In this paper, we examine the features of RSDN-20 signal propagation in a high-latitude Earth–ionosphere waveguide during solar proton events, using computational experiment methods. We have analyzed two proton ground-level enhancement (GLE) events of December 13, 2006 (GLE70) and September 10, 2017 (GLE72). Electron density profiles were constructed using the Global Dynamic Model of Ionosphere (GDMI) and the RUSCOSMICS model, developed at PGI. We present estimated phase and amplitude changes in RSDN-20 signals during precipitation of high-energy protons in the high-latitude region of the Earth–ionosphere waveguide. From the results of computational experiments and the analysis of the electromagnetic signal attenuation based on analytical Maxwell’s equation system solution in magnetized ionospheric plasma, we have found a pattern in the signal attenuation frequency dependence associated simultaneously with the signal reflection height, electron density profiles, and the collision frequency of electrons with neutral particles and ions. We discuss limitations of the computational experiment method and compare simulation results with data from Lovozero and Tuloma observatories.