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The present study develops machine learning-based surrogate models for similarity criterion for solidification. The solidification rate R and Niyama criterion value from the simulation results are compiled, pre-processed, and then used to train the models. A regularization approach is used to minimize variance and avoid overfitting, with the base learners as three-layer artificial neural network (ANN). The predictions from the surrogate model are compared to the training data across both the solidification rate R and Niyama criterion value, considering the different factors affecting the solidification of castings. The trained model has a mean percentage error in the solidification rate R and Niyama criterion value of ~9.89% and ~1.90%, respectively, for the entire dataset. The results show that the predicted and training values are consistent with the parameter changes during the solidification of the castings. Factors affecting the solidification process of castings were evaluated. It is found that the casting temperature has the greatest influence on the solidification of castings, and the validity of the surrogate model is verified by pouring. [ABSTRACT FROM AUTHOR] more...

In the context of tight sandstone reservoirs in the Ordos Basin characterized by compact and heterogeneous rock formations, conventional fracturing techniques yield monolithic fracture shapes, rendering 3D reservoir reconstruction unattainable. This study investigates the principles governing balanced initiation and propagation of fractures in multi-cluster fracturing within unconventional fracturing technology. Employing a large-scale true triaxial simulation experiment system, we utilize the dimensional analysis method (π theorem) to design a physical simulation experiment similarity criterion. Through various experimental adjustments involving proportioning, curing, and mechanical testing, we generate an artificially cured rock mass with mechanical parameters akin to the target layer. The rock mass is maintained at a size of 30 cm × 30 cm × 30 cm. Systematic physical simulation experiments on unconventional volume fracturing are carried out using the 30 cm-sized dense sandstone outcrop rock mass. Taking the conventional fracturing technology as a reference and manipulating experimental conditions and design parameters, we simulate the non-equilibrium initiation and extension behaviors of fracturing fractures under five unconventional volume fracturing technologies, namely hydraulic pulse pretreatment, temporary plugging between clusters, flow-limiting method, cyclic loading and unloading, and pulse intermittent fracturing. Through this, we elucidate the non-equilibrium initiation and extension laws governing multi-cluster fractures. Comparative analysis with conventional fracturing, known for inducing stress interference on fractures and inhibiting their expansion, revels that the five unconventional volume fracturing techniques mitigate stress interference in multi-cluster fracturing. This promotes uniform fracture initiation and expansion, facilitating the creation of complex fractures and larger reconstructed volumes. Among these techniques, inter-cluster block fracturing stands out for its exceptional ability to generate complex fracture networks. The research culminates in the development and refinement of a balanced fracture and extension control technique tailored for multiple cluster fractures in bulk fracturing. This technique significantly contributes to enhancing the degree of 3D reconstruction achievable in unconventional tight oil and gas reservoirs. more...

The problem of buildings and structures durability during their long-term operation in aggressive environments is discussed. It is closely connected with the problem of destruction of composite materials as a random process of birth, development, and death of defects at chemical corrosion. The content of the study is to analyze the influence of non-stationary chemical reactions occurring in real conditions on these processes. The analysis is carried out taking into account the incidental physical phenomena affecting corrosion, the most important of which is the diffusion of initial substances and reaction products occurring under different hydrodynamic conditions, i.e., the nature of fluid motion and its pressure which stimulates corrosion. The synthesis of three processes – chemical kinetics, diffusion, and hydrodynamics – allows us to study one of the possible scenarios of corrosion process development as a Markov process based on the statistical theory of the "weakest" link and the joint distribution of the random material and geometric parameters. Numerical analysis of changes in elastic and electrical properties of composite materials under these conditions allows us to substantiate the technology of non-destructive control of changes in the state of the structure. The research results are based on mathematical and statistical modeling. [ABSTRACT FROM AUTHOR] more...

Abstract Aiming at the problem that the geomagnetic sensor is vulnerable to external interference in the navigation process, this paper analyzes the frequency distribution range of geomagnetic signal and the noise characteristics in geomagnetic signal and proposes an improved morphological filtering and Hilbert–Huang transform (IMMF–IHHT) algorithm to extract and recognize the features of geomagnetic measurement signal. To avoid frequency aliasing and distortion caused by empirical mode decomposition, an improved morphological filtering algorithm based on mean constraint is used to preprocess the measured signal. The Hilbert spectrum of the decomposed signal is solved, the signal components are discriminated by the similarity criterion, and the signal components in line with the frequency range of the geomagnetic signal are extracted and processed to reconstruct the geomagnetic measurement signal. Simulation and experiments show that the signal-to-noise ratio and root-mean-square error of IMMF–IHHT combination algorithm are better than MF-HHT combination algorithm and IHHT algorithm. This algorithm has good signal feature extraction and recognition ability. more...

• A new type of CSHT for a cyclic desalination system was presented. • Establishment of two-phase flow model of heat and mass transfer in FLUENT. • Analysis of factors' influence on thermal performance of CSHT. • Combination of sensitivity analysis and orthogonal test to seek the optimal schemes. • Energy efficiency of CSHT is higher than the national standard in China. This paper designed a kind of circulating solar heat collection tubes (CSHT) for a cyclic desalination system. CSHT was consist of tubes with vacuum layer, I-shaped and U-shaped connectors. In order to analyze the influence of factors of solar intensity (I), inlet fluid temperature (T i), inlet velocity (u) and tube diameter (D) on the thermal performance of CSHT, phase transformation process in tubes was simulated by FLUENT , and User-Defined Functions of mass and heat source terms were introduced. Results showed outlet temperature and vapor mass fraction were both positively correlated with I and T i , but negatively correlated with u and D. Then sensitivity analysis was introduced and conducted for ranking the factors, and their average sensitivity values were in descending order of I , D , u , T i. Under orthogonal test, three optimal schemes (D = 25 mm) of simulation were picked out, and their average heat collection efficiency and exergy efficiency were 81.31% and 77.50%, respectively. Finally, similarity criterion was applied to transmit information of quantitative data from experimental model to corresponding prototype. Through similarity criteria analysis, three optimal schemes were obtained under the condition of tube diameter is 37 mm (diameter is 25 mm in numerical simulation). Optimal operation velocities can be 0.097 m/s, 0.127 m/s and 0.164 m/s respectively in the pilot of CSHT, under the solar intensity values of 800 W/m2, 1000 W/m2 and 1200 W/m2. [ABSTRACT FROM AUTHOR] more...

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

In the three-degree-of-freedom virtual flight test, the scaled model has no translational motion, which will result in the model's dynamics being different from that of free flight, and this difference will directly affect its effectiveness in simulating free flight and the design of the flight control law. In this paper, the longitudinal and lateral-directional dynamic characteristics of virtual flight are studied from the three aspects of modal characteristics, disturbance response characteristics, and control response characteristics. The dynamic characteristic difference between the virtual flight test and free flight is analyzed. In addition, the scaling ratio of the model will also lead to differences in the flight control law design methods of virtual flight and full-size aircraft. The control law design method of the virtual flight test is established by studying the similarity relation of control law parameters between full-size aircraft and the scaled model, and the correctness of similar design of closed-loop control law parameters of the scaled model is verified by a virtual flight test. Finally, the attitude control law parameters obtained from the virtual flight test are applied to the six-degree-of-freedom flight simulation of a full-size aircraft, and the simulation results show that the three-axis attitude control law designed based on the virtual flight test also has good performance in the six-degree-of-freedom flight of the full-size aircraft, and the response of attitude angle and angular rate are approximately the same for both. Generally, the steady aerodynamic data of the aircraft are obtained through the traditional static wind tunnel test to construct the aerodynamic model of the aircraft. The aerodynamic model established by this method may not be able to accurately simulate the actual dynamic flight. However, the actual test flight of full-size aircraft has many disadvantages, such as high cost and high risk. To simulate real flight on the ground, the method of placing the scaled model in a wind tunnel for dynamic flight is proposed, which is called wind tunnel–based virtual flight testing (WTBVFT). The scaled model is connected with the strut through a three-degree-of-freedom rotation mechanism and installed in the wind tunnel test section, so that the model has three degrees of freedom of angular motion and no translational motion. This paper analyzes the differences in dynamics between virtual flight and free flight under open-loop and closed-loop control. The results show that the virtual flight test can simulate the angular motion of free flight well and can be used to design, verify, and simulate the attitude control law of full-size aircraft well. [ABSTRACT FROM AUTHOR] more...

Based on the deformation theory, wear theory and similarity theory, the similarity relations of the various factors influencing the sand erosion phenomenon between in laboratory simulation working condition and in actual working condition were analyzed, and the similarity criterion of the wind sand test was proposed. In order to ensure a mutual conversion between the erosion damages of the engineering materials in the actual wind and sand environment and that in the laboratory simulation environment, this criterion restricted the numerical relations of the various parameters of the wind and sand environment between in actual and laboratory simulation working conditions. By adjusting the proportional relations of the sand - dust concentrations as well as the erosion speeds between in laboratory simulation and actual working conditions, the test speed was controlled and accelerated. Based on this criterion, the values of various parameters in the laboratory simulation wind and sand test could be designed, and the damage degree of engineering materials in the actual wind and sand environment in central and western Inner Mongolia could be predicted through the test mentioned above. The wind and sand test similarity criterion provided a theoretical basis and a basis for parameter selection for evaluating the erosion damage of engineering materials in a wind and sand environment by means of a simulation test. more...

In this research some methods of the similarity theory were quantitatively applied to the description of the relationship between the efficiencies of the photocatalytic hydrogen production and photocurrent generation for the first time. Two possible similarity criteria, namely, such as the ratio of the number of electrons involved in the photocatalytic reaction to the generation of photocurrent ones and the ratio of energies transformed in the case of photocatalytic hydrogen evolution to the photocurrent, were obtained by the dimensional analysis. The literature data allow checking the first criterion. The application of the first possible similarity criterion to the samples with different chemical nature, solid solutions, series, in which the synthesis time or the ratio of catalyst components, electrolyte amount or its nature is changed, was analyzed. It was shown that the ratio of electrons may serve as the similarity criterion only under the conditions of geometric and physical similarities. more...

Hyperspectral images (HSIs) usually have high spectral resolution and low spatial resolution. 3D convolutional neural networks (3D-CNNs) can successfully extract joint spectral and spatial information. But these networks do not provide high reconstruction accuracy in the spatial domain. To solve this problem, a different structure of 3D-CNN is suggested in this work. At first, different levels of decomposition dependent on the image types, i.e., low-resolution (LR) or high-resolution (HR) training images, are performed on the images by using the non-subsampled contourlet transform. To do this optimally, a similarity criterion is defined to determine the appropriate order of the decomposition levels. The defined similarity criterion is also used to select the appropriate training data from among the decomposed components at the network input, for the corresponding output. Then, according to the sparsity value of the decomposed components of LR and HR images, proper 3D-CNNs are individually designed. Finally, the networks are trained based on types of relations between the LR and HR image components. The proposed method is experimented on three different datasets. The results show superiority of the proposed method with respect to some competitors in terms of several measures. [ABSTRACT FROM AUTHOR] more...

Aiming at the problem that the geomagnetic sensor is vulnerable to external interference in the navigation process, this paper analyzes the frequency distribution range of geomagnetic signal and the noise characteristics in geomagnetic signal and proposes an improved morphological filtering and Hilbert–Huang transform (IMMF–IHHT) algorithm to extract and recognize the features of geomagnetic measurement signal. To avoid frequency aliasing and distortion caused by empirical mode decomposition, an improved morphological filtering algorithm based on mean constraint is used to preprocess the measured signal. The Hilbert spectrum of the decomposed signal is solved, the signal components are discriminated by the similarity criterion, and the signal components in line with the frequency range of the geomagnetic signal are extracted and processed to reconstruct the geomagnetic measurement signal. Simulation and experiments show that the signal-to-noise ratio and root-mean-square error of IMMF–IHHT combination algorithm are better than MF-HHT combination algorithm and IHHT algorithm. This algorithm has good signal feature extraction and recognition ability. [ABSTRACT FROM AUTHOR] more...

Model tests are an important method to predict the design and long-term performance of structures and are widely used to analyze the seismic performance, wind resistance, etc., of special structures. For geomaterials, it is difficult to find a material with similar properties to soil in some dimensions. This shortage hinders several kinds of geotechnical model tests that should be implemented with the in situ soil in a 1:1 ratio. Thus, a long-term prediction for tens or hundreds of years cannot be achieved. To guide long-term prediction of freezing soil temperatures, considering the nonlinear change in thermal parameters and the effect of thermal boundary conditions during the soil freezing process, the similarity criterion of the heat conduction process in a frozen soil is derived based on similarity transformation theory. Additionally, for the simulation of frozen soil heat conduction, a general expression of the model soil thermal parameters is given. Based on model tests and numerical simulations, an indirect method is proposed to verify the similarity criterion deduced herein. The results show that the similarity criterion considering the influence of the third kind of boundary conditions is more suitable for engineering practice and can better reflect the evolution of soil freezing temperatures. This research has a theoretical effect on the model test design and model soil preparation of frozen soil temperature fields, and provides a useful method for the future performance prediction of frozen soil thermal problems. [ABSTRACT FROM AUTHOR] more...

Agglomerative Hierarchical Clustering (AHC) is a general type of Hierarchical Clustering (HC) that forms clusters from the "bottom-up." This paper focuses on the development of AHC methods based on ensemble-based approaches. Accordingly, we develop an AHC framework based on clusters clustering along with an innovative similarity criterion that performs clustering through ensemble approaches. The proposed algorithm consists of three main steps. In the first step, a group of single AHC methods are combined to detect relationships between samples and as well as the formation of initial clusters. The similarity of the samples is calculated using an innovative similarity criterion based on the clusters created. In the second step, all the initial clusters created by different methods are re-clustered to form hyper-clusters. After clusters clustering, each sample is assigned to a hyper-cluster with maximum similarity to create the final clusters in the third step. The comprehensive experimental study has been performed to evaluate the performance of the proposed algorithm based on several benchmark datasets from the UCI machine learning repository. The results clearly show that the proposed ensemble AHC-based framework performs better than the state-of-the-art methods. [ABSTRACT FROM AUTHOR] more...

Objectives This paper proposes an experimental bench for manufacturing submersible high-pressure blowing systems (HPBS).MethodsBased on the isentropic blowing model of Laval spray and Bernoulli equations, the mathematical modeling of high-pressure air blowing-off and discharging is accomplished. Based on similarity criterion, a HPBS reduced-scale experimental bench of the Strouhal and the Euler similarity is designed, including the pressure vessel prototype selection and parameter calculation of ballast water tanks and seawater tanks. Under different initial conditions including back-pressures at operating depth of 300, 200 and 100 m, flow areas with sea valve opening degree of 100%, 75% and 50%, and blowing-off pressures of 25, 20 and 15 MPa, the performance of the experimental bench is evaluated. Results The results show that, under the above conditions, the maximal pressure of the compressed air in the ballast water tank is lower than the vessel regulation pressure, and the expansion volume of the compressed air in the ballast is beyond the vessels' regulation cubage.ConclusionsThis proves that the experimental bench can satisfy the performance requirements of submersible HPBS. more...

The research purpose is to develop a methodology that increases the reliability of reproduction and research on models made of equivalent materials of complex nonlinear processes of deformation and destruction of structured rock masses under the influence of underground mining operations to provide a more accurate prediction of the occurrence of dangerous phenomena and assessment of their consequences. New approaches to similarity criterion based on the fundamental laws of thermodynamics; new types of equivalent materials that meet these criteria; systems for the formation of various initial and boundary conditions regulated by specially developed computer programs; new technical means for more reliable determination of stresses in models; new methods for solving inverse geomechanical problems in the absence of the necessary initial field data have been developed. Using the developed methodology, a number of complex nonlinear problems have been solved related to estimates of the oscillatory nature of changes in the bearing pressure during dynamic roof collapse processes; ranges of changes in the frequency of processes during deformation and destruction of rock mass elements, ranges of changes in their accelerations; parameters of shifts with a violation of the continuity of the rock mass under the influence of mining: secant cracks, delaminations, gaping voids, accounting for which is necessary to assess the danger of the formation of continuous water supply canals in the water-protection layer. more...

This study conducted the numerical models validated by wind-tunnel experiments to investigate the issues of Re-independence of indoor airflow and pollutant dispersion within an isolated building. The window Reynolds number (Rew) was specified to characterize the indoor flow and dispersion. The indicators of RRC (ratio of relative change) or DR (K_DR) (difference ratio of dimensionless concentration) ≤ 5% were applied to quantitatively determine the critical Rew for indoor flow and turbulent diffusion. The results show that the critical Re (Recrit) value is position-dependent, and Recrit at the most unfavorable position should be suggested as the optimal value within the whole areas of interest. Thus ReH,crit = 27,000 is recommended for the outdoor flows; while Rew,crit = 15,000 is determined for the indoor flows due to the lower part below the window showing the most unfavorable. The suggested Rew,crit (=15,000) for indoor airflow and cross ventilation is independence of the window size. Moreover, taking K_DR ≤ 5% as the indicator, the suggested Rew,crit for ensuring indoor pollutant diffusion enter the Re-independence regime should also be 15,000, indicating that indoor passive diffusion is completely determined by the flow structures. The contours of dimensionless velocity (U/U0) and concentration (K) against the increasing Rew further confirmed this critical value. This study further reveals the Re-independence issues for indoor flow and dispersion to ensure the reliability of the data obtained by reduced-scale numerical or wind-tunnel models. [ABSTRACT FROM AUTHOR] more...

When heavy equipment are airdropped, the cabin cross-section is largely blocked, and rapid moving of heavy equipment will cause drastic changes in cabin pressure and even damage the health of cabin crew.Therefore, it is necessary to carry out numerical simulation of the pressure change in the airdrop cabin of the transport aircraft, and to lay a foundation for further research.The fluid-solid coupling problem of variable acceleration linear motion in x direction under the combined action of traction pull of parachute, gravity, friction and aerodynamic force in the cabin of transport aircraft is taken as the research object.Based on the motion overset grid, numerical simulation of dynamic pressure variation in the forward compartment of a transport aircraft with heavy load airdrop is carried out.The influence of the model size, incoming velocity, cabin blockage and launching position on the dynamic pressure in the cabin is analyzed, and the similarity criterion related to the cabin pressure during the heavy equipment airdrop wind tunnel test is proposed.The results show that:the closer the airdrop object from the frontal wall cabin, the higher the flow velocity and the bigger the degree of cabin cross-section blockage, the bigger the dynamic pressure change in cabin, and vice versa.In the wind tunnel test, non-dimensional cabin pressure with reference of the front cabin pressure at the airdrop beginning is the most accurate and appropriate cabin pressure similarity criterion. more...

A new method for selecting dimensionless relaxation time in the lattice Boltzmann model was proposed based on similarity criterion and gas true physical parameters. At the same time, the dimensionless relaxation time was modified by considering the influence of the boundary Knudsen layer. On this basis, the second-order slip boundary condition of the wall was considered, and the key parameters in the corresponding combined bounce-back/specular-reflection boundary condition were deduced to build a new model of unconventional gas microscale flow simulation based on the lattice Boltzmann method suitable for high temperatures and high pressures. The simulation results of methane gas flow driven by body force in infinite micro-channels and flow driven by inlet-outlet pressure differential in long straight channels were compared with the numerical and analytical solutions in the literature to verify the accuracy of the model, and the dimensionless relaxation time modification was formally optimized. The results show that the new model can effectively characterize the slippage effect, compression effect, gas density and the effect of boundary Knudsen layer in the micro-scale flow of unconventional natural gas. The new model can achieve a more comprehensive characterization of the real gas flow conditions and can be used as a basic model for the simulation of unconventional gas flow on the micro-nano scale. more...

This paper presents a profound study on the formation of three typical types of defects (i.e., lack of fusion, keyholes, and gas pores) observed in selective laser melting (SLM) printed Inconel 718 samples, along with their correlations with mechanical properties of the samples. Computed tomography, scanning electron microscopy, and mechanical property tests revealed that the three types of defects fall into three stages of porosity evolution classified by recently-proposed dimensionless numbers ηm (melting efficiency) and ηv (vaporization efficiency). Meanwhile, experimental tests verified that the mechanical properties of products, such as strength and elongation, are remarkably sensitive to lack of fusion. However, these properties are slightly affected by the keyholes and gas pores. An optimal process window characterized by dimensionless numbers is realized by adjusting the processing parameters and employing different powders. This process window allows products to have relatively low defects and high mechanical performances. A quantitative relation between processing parameters, dimensionless numbers, defects, and mechanical properties is established based on these observations. This relation, along with the optimal process window, is believed to enhance the quality of SLM products of Inconel 718 alloy and can be further extended to SLM with other metal materials. [ABSTRACT FROM AUTHOR] more...

The main objective of this work is to analyse the problem of determining the boundary of elastoplastic zone with various methods of machining parts by cutting. The structure of complex theoretical and experimental studies of energy–power parameters of the technological processes is considered. The method for calculating the processes of plastic deformation of metals based on a closed set of equations of continuum mechanics is proposed for the theoretical study of energy–power parameters of the technological processes. The expressions, which make possible the reproduction of the spatial pattern of the strain distribution within the metal at the diamond smoothing and grinding, are obtained. This allows visualizing the mechanism of the deformation and simplifying the analysis of the deformed state of the material. Functional relationship between the power of the deformation and parameters of the machining conditions at the diamond smoothing and grinding is established. Various methods for determining the cutting forces during machining with chip removal as well as approaches to determining deflected mode of a material are considered. A method for express calculation of cutting forces using well-known engineering techniques is proposed. The experimental and calculated data on determination of the sizes of plastically deformable zone of difficult-to-cut materials are analysed. The mechanism of inhibition of dislocations and energy conversion during deformation is considered in detail. As a result, a dislocation–kinetic approach is developed, based on the concept of dislocation as a quasi-particle of a strain quantum. Using the dislocation–kinetic approach, the mathematical model is developed, which allows us to calculate a magnitude of the zone of leading cold hardening that is confirmed by comparison with experimental data. The Starkov’s model is improved; the physical meaning of coefficient in formulas for calculating boundaries of cold-hardening zones is explained. A new similarity criterion is introduced, which relates dissipation of plastic strain energy and rate of rearranging of temperature field. more...

A method is proposed for thermal calculation of a new improved design of electrodialysis apparatus. The calculations showed that the mean temperature of the proposed dialyzer design (after 600 sec of solution separation process) is less than the mean temperature of a prototype. With some modification, this method can be used for calculating other electrodynamic apparatuses. [ABSTRACT FROM AUTHOR] more...

The comparison of head-related transfer functions (HRTFs), e.g., for validating different acquisition methods, requires a meaningful way of quantifying HRTF differences – a problem to which literature offers no standardized approach. This impedes the comparability and interpretability of studies. The present work therefore addresses the lack of proper understanding of the behavior of commonly used distance metrics by applying seven metrics to individually measured and approximated HRTF datasets. Covering a variety of spectral deviations, we perform both intra-individual comparisons (contrasting different levels of spectral detail for the same individual) and inter-individual comparisons (assessing metric reactions to non-individual cue differences). The metrics exhibit selective reactions to distinct spectral alterations. Particularly, the results demonstrate that spectrally localized errors go undetected by five out of seven metrics. Further analysis emphasizes inconsistencies in metric correlation patterns. These observations highlight the need for a multi-dimensional metric, capturing various types of HRTF differences for a proper assessment of errors. more...

It is necessary to simulate effects of propeller power accurately, when the stall performance of propeller aircraft is simulated by scaled free-flight test. Based on the analysis of similarity criterion of the model's free flight stall test and the similarity criterion of the propeller's dynamic model, the similarity criterion relation to be followed in the free flight stall test of the propeller model is deduced. Actual free-flight test is performed to examine the method by aircraft model with four turbo-prop engines. The free-flight test result shows that the method can reflect the state of propeller power operation at the stall, the stall speed and stall characteristics accurately and agree with the results obtained by wind tunnel test. It can provide important data support for aircraft stall test flight, and provide theory and test method for domestic research on free flight test of propeller model. more...

Introduction. The problem of adequate modeling of physical processes and objects is an urgent task of modern science. Automation of work in this area increases the accuracy of modeling and saves money on full-scale modeling of objects under study. The research objective was to create a computer program that would automatically form dimensionless similarity criteria based on the initial set of parameters.Materials and Methods. The calculation algorithm is based on к-theorem of similarity theory and the basic provisions of the dimensional theory.Research Results. The computer program is developed. It enables to get all the theoretically possible similarity criteria for the simulation of the physical process or object of interest. Discussion and Conclusions. The results obtained can be used in the industrial and scientific modeling of physical objects of research, calculation of new similarity criteria, solving problems of describing complex processes, etc. more...

3D-HEVC is the state-of-the-art standard to compress three-dimensional videos. One of the 3D-HEVC novel tools is the DIS tool, which is used to efficiently compress smooth and homogeneous areas of depth maps by using four different prediction modes. The decision of which DIS mode will be used is done through the SVDC similarity criterion in the DIS original definition. This article proposes the substitution of the complex SVDC criterion for simpler and more hardware friendly criteria as SATD, SSE, and SAD. These alternative criteria were evaluated in terms of encoding efficiency and hardware impacts in comparison with the SVDC. Dedicated DIS hardware were designed using each one of each criterion and these designs were described in VHDL and synthesized for TSMC 40 nm. The best results were found with SAD criteria, with losses of only 0.2% in coding efficiency and with expressive gains of more than 50 times in power and more than 35 times in area, when compared with SVDC. The reached results showed that the use of a simpler similarity criterion is an important alternative to be used in DIS tool, mainly if an efficient hardware design is required. [ABSTRACT FROM AUTHOR] more...

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

The object of research is the methods of handwriting recognition. The article reviews the basic principles of optical recognition. The aim of the work is to present an algorithm for text recognition in the image, which has high accuracy with a small training sample. To achieve this goal, an original similarity criterion is proposed, which can be used to effectively compare the formed structural models of symbols. The reader is offered a detailed consideration of the algorithm of the mentioned similarity criterion. Ref. 5, pic. 4 more...

The relevance of research of material strain nature based on physical models equivalent to rocks is substantiated. To identify the dependencies and mechanism of unstable rock strain in the vicinity of mine working junctions, an experimental technique has been developed and presented. The method of physical modeling using equivalent materials was applied in the research. Strength characteristics of the rock equivalent material were calculated using the formulas proposed by G.N. Kuznetsov. The equivalent material was prepared based on two components, sand and paraffin. The mix formulation was selected, and ultimate compressive strength of the equivalent material was determined. The experiment was performed for three options of the physical models: an intact rock mass, a rock mass with a single mine working, and a rock mass with mine working junctions. Testing of the models made of the equivalent material was performed through uniaxial vertical loading using a hydraulic press. Based on the model testing findings, the dynamics of fracture propagation and crushing of the enclosing equivalent material in the vicinity of an artificial cavity, simulating a mine working, has been demonstrated. Besides, the graphs of relative strain versus vertical loading for each stage of the stepwise loading of these three model options were produced. The findings of the strain-stress distribution modeling for the equivalent material around the cavities simulating mine working junctions were analyzed. The strain testing findings for the materials simulating rock behavior are expected to be used as the initial data for analysis of physical and numerical simulation, as well as for developing engineering documentation with regard to the selection of parameters for supporting mine working junctions. more...

Flow characteristics inside the compressor are of great importance for aeroengine performance under the high adverse pressure gradient. To meet the need for quick performance estimation, the numerical simulation is a meaningful investigation method to predict the similarity flow characteristics of aeroengine compressor at high Mach flight. Thus, this paper aims to satisfy the accuracy of compressor flow field at high altitude based on the similarity criterion. The accuracy for solution results by the application of the similarity criterion and the derivation of compressor boundary conditions is verified with the experimental data. Then, the parametric definitions of air intake are put forward to get the inlet boundary conditions of compressor. The comparative simulation results are conducted between similarity and prototype flow fields at design boundary conditions. The results show that among the most important dimensionless criterion is Mach number at high-speed flow, so the same equivalent mass flow and equivalent speed are recommended. In addition, the flow characteristics of the compressor at high altitude and high Mach number have a good similarity. Consequently, it can extend to further study compressor performance of aeroengine at different flight altitudes and Mach numbers. more...

Heavy K-type derrick is one of the most important load-carrying parts in deep well oil drilling rig. Field test is a useful way of obtaining the dynamic characteristic parameters of the derrick but inherent disadvantages such as high cost, site condition limit its application. It is economical and effective to make reduced-scale dynamic model and do experiments for improving design of the derrick prototype. Based on similarity principle, we develop a reduced-scale dynamic model of the derrick prototype with geometric similarity ratio of 10. Dynamic test for the model and harmonic-response analysis for the derrick prototype have been conducted, respectively. The result shows that the maximum deviation of frequency and displacement between test and analysis is small, which proves the rationality and validity of the design and manufacturing of the dynamic model. Also, the test and harmonic-response analysis data indicate that in drilling process, the rotation of the rotary table can hardly ever cause the severe vibration of the derrick. The experimental dynamic test of reduced-scale derrick model can replace the field test of the derrick prototype and provides reference for dynamic characteristic research of the derrick prototype. [ABSTRACT FROM AUTHOR] more...

The ensemble clustering tries to aggregate a number of basic clusterings with the aim of producing a more consistent, robust and well-performing consensus clustering result. The current paper wants to introduce an ensemble clustering method. The proposed method, called consensus function based on two level clustering (CFTLC), introduces a new consensus clustering where it makes a cluster clustering task through applying an average hierarchical clustering on a cluster–cluster similarity matrix obtained by an innovative similarity metric. By applying the average hierarchical clustering algorithm, a set of meta clusters has been attained. Considering each meta cluster as a consensus cluster in the consensus clustering output, it then assigns each data point to a meta cluster through defining an object-cluster similarity. Before doing anything, CFTLC converts the primary partitions into a binary cluster representation where the primary ensemble has been broken into a number of basic binary clusters (BC). CFTLC first combines the basic BCs with the maximum cluster–cluster similarity. This step is iterated as long as a predefined number of meta clusters are ready. At the subsequent step, it assigns each data point to exactly one meta cluster. The proposed method has been experimentally compared with the state of the art clustering algorithms in terms of accuracy and robustness. [ABSTRACT FROM AUTHOR] more...

Molecular‐docking is an essential tool in the drug designing process, where a small molecule ligand (drug) binds with disease‐causing protein molecule to prevent its further activity. Docking process helps in predicting the most appropriate configuration and the optimal interaction energy between the interacting molecules (ligand and protein) to form a stable complex. Based on this idea, a new learning‐based single image super‐resolution reconstruction (LSI‐SRR) method is proposed here. Estimation of a high resolution (HR) patch is achieved by optimising the interaction energy between the input low resolution patch and its corresponding candidate patches appropriately chosen from the training image dataset via Genetic algorithm. Structured‐spatiogram based measure; a new and competent similarity criterion is proposed to select potentially efficient training images which encompass better statistical and structural co‐relation with the input image. The proposed method is tested on synthetic and real‐time images at different magnification factors. Performance analysis of the proposed work is compared with some of the representative state‐of‐the‐art LSI‐SRR methods. Experimental results demonstrate that the proposed method produces HR images with enhanced image details, minimal artefacts and most importantly enables an efficient trade‐off between the image qualities to speed than the competing methods. [ABSTRACT FROM AUTHOR] more...

The water supply system of Sanhekou Water Control Project adopts DN2000 large diameter regulating valve, which has not been used in practice. Therefore the model test is used to simulate the valve and verify the prototype design. In this paper, a 1:5 scale model was set up according to the geometric similarity criterion and the DN400 model was used to simulate the prototype. The results show that the DN2000 large caliber valve has better capacity of flow and pressure regulation. The test results of the model parts are in good agreement with the CFD calculation results mid the model parts meet the similar-design criteria. [ABSTRACT FROM AUTHOR] more...

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

Copyright of Progress in Physics of Metals / Uspehi Fiziki Metallov is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

At present, ship model tests are based on the normal mode at home and abroad. With the development and application of abnormal hydraulic model, it is necessary to study abnormal ship model. The similarity criterion of abnormal ship model is deduced from the similarity theory of normal hydraulic model in this paper. Some factors that affect the maneuverability of the abnormal ship model are discussed by theoretical analysis of ship maneuvering. The influence of the K and T index of different variable rate on the abnormal ship model maneuvering and the dimensional effect of the abnormal ship model are obtained, which can be used as a reference for the study of the abnormal ship model. more...

In navigation work, the geomagnetic sensor signal is susceptible to interference, so the calibration process is necessary to compensate sensor model error. However, we found the noise error in the geomagnetic sensor leads to a considerable calculation error in the calibration coefficient matrix, which is a big obstacle in obtaining the accurate signal. To improve the calibration effect, this paper analysis the characteristic of geomagnetic sensor’s noise error, and then proposes the improved Hilbert-Huang transform (IHHT) algorithm to preprocessing these noise before calibration. IHHT creatively proposes an attention Hilbert spectrum, which is robust to strong noise recognition and localization. The adaptive median filtering is employed on strong noise regions. Additionally, a similarity criterion for Intrinsic Mode Function (IMF) processing is presented to save computational resources and time. Confirmed by simulation, IHHT algorithm depresses noise to be close to 0 mGuass, and declines sample variance to 13.963 $mGuass^{ {2}}$ , which shows effective noise reduction capability. The experiment result shows IHHT algorithm considerably enhances calibration performance, as the calibration error drops by more than 50% compared with the results using state-of-the-art methods. [ABSTRACT FROM AUTHOR] more...

Featured Application: A new approach for investigating snowdrifts around buildings and snow loads on building roofs based on a new facility named the "snow–wind combined experimental facility" is proposed in this paper. First, the method proposed in this paper is convenient and economical, and also the experimental results prove that the method is feasible and reliable. In this paper, only experiments on snowdrift around a cube were chosen for the verification for the sake of generality, but this method could also be adopted for the prediction of snowdrift around complex building environments and snow loads on various shapes of building roofs. Unbalanced, or non-uniform, snow loads caused by snow drifting or sliding in cold regions with heavy snowfalls, can be a serious problem for the building industry. However, the methods for predicting snow distribution still need to be improved. Field observation is the most direct and reliable method to study snow distribution, but because the natural environment is uncontrollable and varies dramatically, sometimes conclusions may be confused under the influence of the many variables in the investigation. This paper proposes a snowing experiment approach using an outdoor snow–wind combined experiment facility for the study of snow distribution. The facility can produce a stable and controllable wind field and snowfall environment. Experiments which focused on snowdrift around a building were conducted during the winter to make an evaluation of the repeatability and reliability of the new approach. Finally, from the analysis of results, it was demonstrated that the experimental facility was stable and that the similarity criterion adopted for the snowing pattern was reliable. Especially, the minimum value of the friction speed ratio was suggested to ensure the test accuracy. [ABSTRACT FROM AUTHOR] more...

Flow characteristics inside the compressor are of great importance for aeroengine performance under the high adverse pressure gradient. To meet the need for quick performance estimation, the numerical simulation is a meaningful investigation method to predict the similarity flow characteristics of aeroengine compressor at high Mach flight. Thus, this paper aims to satisfy the accuracy of compressor flow field at high altitude based on the similarity criterion. The accuracy for solution results by the application of the similarity criterion and the derivation of compressor boundary conditions is verified with the experimental data. Then, the parametric definitions of air intake are put forward to get the inlet boundary conditions of compressor. The comparative simulation results are conducted between similarity and prototype flow fields at design boundary conditions. The results show that among the most important dimensionless criterion is Mach number at high-speed flow, so the same equivalent mass flow and equivalent speed are recommended. In addition, the flow characteristics of the compressor at high altitude and high Mach number have a good similarity. Consequently, it can extend to further study compressor performance of aeroengine at different flight altitudes and Mach numbers. [ABSTRACT FROM AUTHOR] more...

• A new similarity criterion for FOWT's model testing is proposed; • The optimal TSR matching of the prototype and the model is taken into account; • The similarity of the reduced frequency is taken into account; • Numerical simulations under surge motion show better reproduction of prototype turbines. Floating offshore wind turbines have rapidly advanced in recent years, prompting numerous experiments. Small-scale turbines require blade redesign with low Reynolds number airfoils due to the scale effect. Consequently, the chord length of these blades no longer corresponds to the length scale, leading to dissimilar dynamic aerodynamic phenomena during platform movement. To address this, a new criterion is proposed for wind tunnel tests of floating offshore wind turbines. The criterion incorporates reduced frequency correction and optimal tip speed ratio (TSR) matching. It ensures hydrodynamic similarity through Froude number similarity and avoids excessive low wind speed through wind speed correction. Optimal TSR matching ensures the model and prototype turbines operate within similar power curve intervals. Reduced frequency corrects the platform sine motion parameters, providing the model turbine with a dynamic aerodynamic effect similar to the prototype. The National Renewable Energy Laboratory's 5 MW wind turbine is chosen as the prototype, and the model wind turbine blades are designed using NACA 4412 airfoil and the criterion of thrust coefficient similarity. The sub-module of the FAST, AeroDyn is employed to validate the new criterion for different surge motions between the NREL 5 MW and the model. Under the new similarity criterion, the model turbine exhibits a relative root mean square error of 4.61 % and 1.54 % in power coefficient and thrust coefficient, a significant improvement compared to the current similarity criterion's relative root mean square error of 24.74 % and 8.36 %. The results reveal a circular trend variation in both thrust coefficient and power coefficient with position. Notably, the new criterion demonstrates a closer alignment with the dynamic aerodynamic characteristics of the prototype when contrasted with the current similarity criterion. Furthermore, this model design, tailored for the NREL 5 MW turbine, can be applied to model experiments with various turbine configurations. It has been successfully verified for the IEA 15 MW turbine, exhibiting promising simulation results. The proposed similarity criterion is suitable for wind tunnel testing, addressing the problem that the current similarity criterion cannot reflect the dynamic aerodynamic characteristics of prototype wind turbines. Additionally, it enables experiments on different prototype configurations using a single model turbine, reducing wind tunnel testing costs. [ABSTRACT FROM AUTHOR] more...

The objective of the current research was to develop methodology for diagnosing industrial gas turbine engine bearings using the standard performance parameters. This paper presents mathematical thermal model of combined thrust and radial bearing and provides the model application examples for diagnostics. more...

In the article, using the criterion analysis method, the analysis of the stability of total costs, the sensitivity of parameters to changes in the initial data (to the analysis of the influence of errors in the initial data) is carried out, and recommendations are given on the use of the obtained parameters for 10 kV distribution electrical networks. more...