Scale Model Research Articles

Optimized identification process of equivalent wind load calculations for offshore wind turbines under standstill conditions

In engineering, the wind excitations acting on the offshore wind turbine (OWT) structure cannot be obtained directly by the measured method. The traditional load simulation way may lead to poor accuracy because of the deviation between actual operational conditions and simulation environment parameters or load coefficients, which are always selected based on load spectrums, small scale model tests and engineering experience. To solve this project problem, an equivalent wind load optimization model and parameter identification process of OWT was established under the standstill conditions. Afterwards, two key load parameters in load model respectively called constant drag coefficient and unsteady lift coefficient can be obtained through recursive call on numerical model and feedback analysis using particle swarm optimization (PSO) algorithm based on measured vibration data. The applicability and accuracy of proposed calculation process was verified through an equivalent numerical model of OWT considering different particle position and wind speed. Further, the optimization identification on equivalent wind load and the drag and lift coefficients of one OWT was achieved based on measured data. It is illustrated that the identified drag coefficients show a drop trend from 0.629 to 0.154, consistent with the parameter range of 0.20–0.60 obtained from model experiments, before the wind speed reaches 6.0 m/s and then rise obviously with the increase of wind speed. On the contrary, the range of optimized lift coefficients form 0.133–0.480, which is as familiar as the experimental parameter range of 0.10–0.30, reflects a certain increase trend. Finally, the comparison between identified wind excitations and calculated loads based on the measured strain data explain that the proposed load optimization identification process have a good credibility on actual OWT.

Pengaruh Work Life Balance dan Lingkungan Kerja Non Fisik terhadap Kinerja Pegawai Pada Badan Kepegawaian Daerah Provinsi Sumatera Barat yang Dimediasi Kepuasan

Life balance in the implementation of work is an inseparable part of achieving employee job satisfaction, while job satisfaction is one of the most important parts of employee performance so that company goals are achieved effectively and efficiently. The aim of this research is to analyze the influence of work life balance and non-physical work environment on the performance of employees of the Regional Civil Service Agency of West Sumatra Province which is mediated by job satisfaction. The total population in this study was 73 people who were the samples in this study using the census or saturated sample method. Data was collected through distributing questionnaires with a Likert scale model and then testing the validity and reliability of the questionnaire. The data analysis technique used is the Smart PLS method. The results of this research are that work life balance has a positive and significant influence on employee performance at the Regional Civil Service Agency of West Sumatra Province; The non-physical work environment has a positive and significant influence on employee performance at the West Sumatra Province Regional Civil Service Agency. Work life balance has a positive and significant influence on job satisfaction at the Regional Civil Service Agency of West Sumatra Province. The non-physical work environment has a positive and significant influence on job satisfaction at the Regional Civil Service Agency of West Sumatra Province. Job satisfaction has a positive and significant influence on employee performance at the Regional Civil Service Agency of West Sumatra Province. Work life balance can be mediated by job satisfaction on employee performance at the Regional Civil Service Agency of West Sumatra Province. The non-physical work environment can be mediated by job satisfaction on employee performance at the Regional Civil Service Agency of West Sumatra Province.

An improved similarity method for stiffened plates subjected to combined loads of longitudinal compression and lateral pressure

Structures’ ultimate strength has been increasingly valued in the past few decades. The model test is an important and reliable way to estimate the ultimate strength. For large and complex structures, like ship hull structures, the test subject is usually scale models due to the limitation of loading capacity and space of laboratories. Therefore, the similarity method and the design of scale models are of great importance. The stiffened plate is the minimum unit that makes up thin-walled structures. The similarity method of the ultimate strength of stiffened plates is the base of the similarity method of large and complex structures. This paper is a further study of an existing similarity method proposed in our previous work. A stiffened plate from a real ship is taken as the subject. 22 combinations of scale ratios are used to design scale models. The 23 models (including the original model) are subjected to a combined load of longitudinal compression and lateral pressure. The non-linear finite element method is used to analyze these models. The results revealed that the previous method is only suitable for scale models with small degrees of geometrical distortion. It didn't consider the effect of geometrical distortions. An improved similarity method and scale model design method are proposed to solve these problems. The improved methods consider the geometrical distortion of scale models and are applicable to more geometrically distorted scale models. More numerical examples are performed to verify the correctness and advantage of the improved methods.

Investigation of Improved Energy Dissipation in Stepped Spillways Applying Bubble Image Velocimetry

This study investigates skimming flow regimes, two-phase air–water flow conditions, and simple measures to improve energy dissipation in stepped spillways. Experiments were conducted using two different scale physical models, 1:50 and 1:17, within separate rectangular flumes to define scale effects. Flow patterns were analyzed using the Bubble Image Velocimetry (BIV) technique, which tracks air bubbles. The introduction of splitters resulted in a 7% increase in relative energy dissipation. Additionally, the length of inception was reduced to Li/ks = 10, thereby decreasing the potential for subsequent cavitation. Beyond the BIV experiments, two experiments were conducted on the large-scale model using Acoustic Doppler Velocimetry (ADV), with and without splitters, to examine the impact of splitters on the velocity profile above the crest. In the experiment with splitters, the vertical velocity vector (v) contributed to turbulence by changing direction, thereby reducing average velocities both in front of and behind the ogee crest. This led to a reduction in energy on the downstream side of the spillway. Although the small-scale model appears unsuitable for studying two-phase flow, the change in relative energy dissipation from the baseline to the splitter configuration was practically identical for both scale models, thereby supporting the findings of the large-scale model.

Technology-Enhanced Feedback System Usability in the Context of Self-Regulation Promotion

Numerous studies have explored the integration of technology-enhanced feedback systems in education. However, there is still a need for further investigation into their specific impact on teacher satisfaction, which is essential for effective feedback delivery to students. This study addresses this gap by analyzing teachers’ satisfaction with the “Compliments and Comments Tool”, a technology-enhanced system developed to provide written feedback to students. Using a quantitative approach, this study examined teachers’ perceptions of the tool’s usability in the Slovenian education context, involving a diverse group of 3412 primary and secondary school teachers. Data were collected through surveys employing the System Usability Scale (SUS) and Technology Acceptance Model (TAM) for quantitative analysis, complemented by qualitative insights. The results showed high teacher satisfaction, valuing the tool for facilitating feedback and supporting a positive learning environment. These findings suggest that the “Compliments and Comments Tool” is a valuable addition to educational technology, promoting effective teaching and enhancing student engagement. This study emphasizes the critical role of user-centered design and system usability in educational technology, particularly in fostering effective feedback and promoting student self-regulation.

Study on static performance and dynamic characteristics of a spoke cable-truss suspen-dome system

The proposed spoke cable-truss suspen-dome structure is a new structure system based on the traditional chord-supported dome structure. In this structure, the upper lattice shell is modified to a radial cable-truss structure. The lower part of the structure is a cable network structure composed of radial cables, ring cables and radial cables. There are few research results on the mechanical properties of the new structure, so a 1:10 scale model is established, multi-condition static loading test, local cable force failure test and natural vibration characteristic test are carried out, and the measured results are compared with the finite element results. The changes of axial force and joint displacement under different loads, the changes of static properties under cable damage and the dynamic characteristics of the structure are obtained. The results show that the loading method adopted meets the test accuracy requirements. Under the action of uniform load, the upper chord, the lower chord end and the inner ring truss of the main truss are in a pure compression state. The middle bar of the lower chord span and the outer ring truss change from the compression state to the tension state with the increase of load. The structure is still in the elastic stage when part of the cable fails, and the coordinated deformation ability is strong. The base frequency of the measured structure is 7.97 Hz, and the stiffness distribution is uniform.

Particle image velocimetry in the impeller of a centrifugal pump: Relationship between turbulent flow and energy loss

Turbulent flows play a dominant role in the operation of centrifugal pumps, which find widespread use in industrial settings and various aspects of human life. The dissipation rate of turbulent kinetic energy emerges as a key parameter within these devices, with its local values exerting a significant influence on centrifugal pump performance. Recent advances in particle image velocimetry (PIV) techniques have expanded the ability to analyze complex turbulent flows across a broad spectrum of scales. In this context, this paper aims to deepen our understanding of the turbulent flow field and its correlation with energy loss in centrifugal pump impellers. To achieve this, experiments were conducted using PIV on a transparent pump operating under different conditions. Statistics of the turbulent flow were then obtained from phase-ensemble averages of velocities, vorticity, turbulence production, and local dissipation of turbulent kinetic energy. To overcome the limited spatial resolution constraint of PIV, the large-eddy PIV (LES-PIV) method was employed to estimate the local dissipation rate. In this method, it is assumed that the motion of larger scales is measured by the PIV technique, while the smaller scales (unresolved scales) are modeled by a sub-grid scale model, calculated from the strain rate tensors obtained from the measured fields. Energy losses in the impeller were studied using two methodologies: (i) a conventional method based on power measurements, and (ii) an alternative approach based on the budget of turbulent kinetic energy. Our results reveal that turbulent loss caused by turbulence production is the main source of energy loss in the pump impeller, and it is particularly pronounced in low-flow operating conditions characterized by large-scale structures. On the other hand, in situations where flow rates exceed the best efficiency point (BEP) condition, the predominant flow structures are marked by small-scale features, mainly attributed to local dissipation of turbulence. Our findings clarify the characteristics of energy losses in centrifugal pump impellers and their relationship with the turbulent flow field, and, in addition, providing a methodology for calculating the local turbulent dissipation rate and its limitations when derived from PIV measurements.

Caffeine removal using brewery’s spent grain modified with H3PO4: experimental observation and statistical analysis

This work studied the performance and reusability of the biosorbent obtained from a brewery’s spent grain (BSG), applying experimental observation and statistical analysis to caffeine removal from the real matrix. A study of caffeine removal on a batch scale, through kinetic and isotherm models, applying classical and Bayesian statistic criteria, was performed to choose the most adequate model and estimate the maximum amount adsorbed (qmax) and the equilibrium constant (Ke). The biosorbent regeneration through ultrasound and thermal oxidation and the biosorbent characteristics—including the structural changes after the regeneration cycles—were also evaluated. The best operational conditions for caffeine removal (above 80%) were obtained at natural pH and adsorbent dosage of 20 g L−1, with the qmax ranging from 5.86 to 8.83 mg g−1. Results demonstrate that acid sites disappear after adsorption indicating that caffeine binds to the adsorbent surface through hydrogen bonds (chemisorption occurrence hypothesis). The biosorbent was regenerated eight consecutive times and kept the adsorption performance above 60%. Besides, it was efficient in the alkalinity removal (80%), inorganic carbon (95%), and caffeine (98%), which shows the potential for application in the treatment of aqueous matrices.

The Impact of Bureaucratic Structures on the Performance of School Principals in Public Secondary Schools

The study investigated into bureaucratic role of principals’ leadership performance in public senior secondary schools in Rivers State. The study adopted the descriptive research design. The population of the study consisted of the two hundred and ninety six (296) principals in all the two hundred and ninety-six (296) public senior secondary schools in the 23 Local Government Areas of Rivers State. The sample of this study comprised the two hundred and ninety-six (296) principals selected from the two hundred and ninety-six (296) public senior secondary schools in the twenty three (23) Local Government Areas in Rivers State, representing 100% of the population using the census sampling technique. Out of the 296 copies of questionnaires distributed 275 representing 96% of the total number of copies, were duly completed and returned. The instrument for data collection for this study was a 30 item self-structured questionnaire titled ‘Bureaucratic Role of Principals’ Leadership Performance Questionnaire (BRPLPQ)”. The instrument was structured using the modified 4-points Likert Scale model of; Very High Extent (VHE) – 4 points; High Extent (HE) =3 points; Low Extent (LE) = 2 point and Very Low Extent (VLE) =1 point.

Active Diagnostic Experimentation on Wind Turbine Blades with Vibration Measurements and Analysis

Abstract This paper deals with the key operational problems of wind turbosets, especially offshore, where vibrations are generated by rotor blades, as a consequence of erosive wear or icing. The primary causes of the imbalance of wind turbine rotors have been characterised, the observable symptoms of which include various forms of vibrations, transmitted from the turbine wheel to the bearing nodes of the power train components. Their identification was the result of an active diagnostic experiment, which actually entered the aerodynamic-mass imbalance of a turbine rotor into a wind power train, built as a small scale model. The recording of the observed monitoring parameters (vibration, aerodynamic, mechanical and electrical) made it possible to determine a set of symptoms (syndrome) of the deteriorated (entered) dynamic state of the entire wind turboset. This provides the basis for positive verification of the assumed concept and methodology of diagnostic testing, the constructed laboratory station and the measuring equipment used. For this reason, testing continued, taking into account the known and recognisable faults that most often occur during the operation of offshore wind turbosets. Transferring the results of this type of model research to full-size, real objects makes it possible to detect secondary (fatigue) damage to the elements transmitting torque from the wind turbine rotor to the generator early, especially the thrust bearings or gear wheel teeth.

Pengembangan Sumber Daya Manusia Sebagai Faktor Yang Mempengaruhi Produktivitas Kerja Rumah Sakit Sari Asih Karawaci

Human resource development is a factor that has been empirically proven to have a significant influence on work productivity. This article discusses the results of research on the influence between the two variables. HR as a process in which employees are assisted continuously and planned to acquire or sharpen the abilities necessary to perform various functions related to their current or expected roles in the future. The explanation of HR development also aims to develop employees' abilities as individuals and find and utilize employee potential for the purpose of self-development and/or the company. This study was conducted using a rating scale model questionnaire given to respondents of 57 employees of Sari Asih Karawaci Tangerang Hospital who was the object of the research. The descriptive analysis conducted shows that human resource development is in the effective category while work productivity is in the medium category. The analysis shows that human resource development has a positive and significant influence on work productivity. To increase work productivity, employees must improve their knowledge, skills and motivation so that work productivity can be obtained optimally.

A comparative numerical investigation of effect of mechanical compression on the transport properties of gas diffusion layer fabricated by wet and dry laid methods

The gas diffusion layer (GDL), a core component of the proton exchange membrane fuel cell (PEMFC), is integral to thermoelectric and gas-liquid transport. Recognizing the impact of mechanical compression on transport properties and cell performance, it is crucial to comprehensively study the GDL's effect on effective transport performance. In this study, two types of GDLs, Toray GDL fabricated by wet-laid and Freudenberg GDL fabricated by dry-laid, are first reconstructed. Then, their stress-strain distributions under various mechanical compression ratios from 0 to 40 % are simulated using the finite element method, along with the effects of mechanical pressures on the microstructural parameters. Finally, a pore scale model is utilized to obtain the effective transport properties of the two types of GDLs under ten different compression ratios. The results show that Freudenberg GDL exhibits a more rapid stress transfer with a more uniformly distributed stress, while Toray GDL displays a slower stress transfer with a more differentially distributed stress. Notably, the pore size decreases significantly by approximately 60 % in both GDL types when the compression ratio increases from 0 % to 40 %. As the mechanical compression ratios increases from 0 to 40 %, the tortuosity of Toray GDL and Freudenberg GDL in the in-plane/through-plane direction increases by 78 %/50 % and 81 %/86 %, respectively. The conductivity of Toray GDL and Freudenberg GDL increases by 150 %/650 % and 130 %/140 % in the in-plane/through-plane direction, respectively, when the compression ratio is increased to 40 %. Additionally, a 20 % compression ratio is identified as an optimal point for both GDLs to balance gas diffusion and thermoelectric conduction.

TEMPRO: nanobody melting temperature estimation model using protein embeddings

Single-domain antibodies (sdAbs) or nanobodies have received widespread attention due to their small size (~ 15 kDa) and diverse applications in bio-derived therapeutics. As many modern biotechnology breakthroughs are applied to antibody engineering and design, nanobody thermostability or melting temperature (Tm) is crucial for their successful utilization. In this study, we present TEMPRO which is a predictive modeling approach for estimating the Tm of nanobodies using computational methods. Our methodology integrates various nanobody biophysical features to include Evolutionary Scale Modeling (ESM) embeddings, NetSurfP3 structural predictions, pLDDT scores per sdAb region from AlphaFold2, and each sequence’s physicochemical characteristics. This approach is validated with our combined dataset containing 567 unique sequences with corresponding experimental Tm values from a manually curated internal data and a recently published nanobody database, NbThermo. Our results indicate the efficacy of protein embeddings in reliably predicting the Tm of sdAbs with mean absolute error (MAE) of 4.03 °C and root mean squared error (RMSE) of 5.66 °C, thus offering a valuable tool for the optimization of nanobodies for various biomedical and therapeutic applications. Moreover, we have validated the models’ performance using experimentally determined Tms from nanobodies not found in NbThermo. This predictive model not only enhances nanobody thermostability prediction, but also provides a useful perspective of using embeddings as a tool for facilitating a broader applicability of downstream protein analyses.

Countercurrent Imbibition in Porous Media with Dense and Parallel Microfractures: Numerical and Analytical Study

Summary Countercurrent imbibition is the process in which the wetting fluid spontaneously displaces the nonwetting fluid, while the nonwetting fluid is recovered at the wetting fluid inlet. It is a major mechanism for the recovery of shale oil, shale gas, and tight oil. In shale and tight formations, microfractures are highly developed. Specifically, some typical formations, such as continental shales, consist of dense and parallel microfractures (DPFs). In DPF systems, microfractures are segregated by low-permeability matrix layers, while the very close distance betwen neighboring microfractures results in strong capillary correlation. The underlying assumptions of the classical dual-porosity (DP) model break down. Despite extensive studies on layered media, there is still no suitable model to describe imbibition in the DPF system at the representative elementary volume (REV) scale. In this study, we first numerically simulate countercurrent imbibition in DPF systems with fine grids, adopting typical continental shale parameters. For imbibition parallel to microfractures, two distinct stages are identified: an early stage where fractures are not correlated and a late stage where neighboring fractures are strongly correlated by capillarity. In both stages, cumulative oil production (Q) is proportional to the square root of imbibition time (t1/2), while the prefactors are very different. The late stage is the dominant stage in oil recovery. We note that the matrix permeability rarely contributes to imbibition parallel to microfractures at the late time, indicating that the matrix’s role here is to store fluid rather than to provide flow resistance. In addition, we rationalize the failure of the classical DP model, as it significantly overestimates fracture-matrix fluid exchange near the displacement front. Similarly, for imbibition perpendicular to microfractures, Q is also proportional to t1/2 in the late stage. After elucidating the mechanisms of fracture-fracture capillary interaction, we successfully derive analytical solutions for uni-directional countercurrent imbibition kinetics in DPF systems at the late stage, for imbibition parrallel and perpendicular to microfractures, respectively. We accordingly propose an equivalent REV scale model and examine it with fine-grid simulations. We highlight the importance of adopting anisotropic relative permeability in this DPF system at REV scale for reservoir simulation rather than simply adopting anisotropic absolute permeability. This presents a new challenge for numerical simulations at reservoir scale.

Analysis of The Efficiency of Public Expenditure on Education in Elementary Education in The State of Alagoas

Objective: This article analyzes the efficiency of public spending on education in the municipal public network in elementary education, in all cities in Alagoas, using the data envelopment analysis method, DEA. Theoretical Framework: The present work used the variable return to scale (BCC) model, since we would be dealing with municipalities with varied realities. There are two basic ways for a unit that is inefficient to become efficient. The first would be to reduce resources (inputs) and keep products constant, which would be an input-oriented orientation; the second would be doing the opposite, increasing the result (products) from the same amount of inputs, an orientation focused on outputs. Method: The data envelopment analysis method - DEA is used to estimate efficiency with traditional inputs such as school infrastructure, capital, labor and municipal wealth. As output, the Portuguese and mathematics grades in the 9th grade, in the Saeb 2019 test, are considered, multiplied by the students enrolled in this year of education; as well as the inverse of per capita expenditure on elementary education. Results and Discussion: It was concluded that most of the benchmarkings are represented by municipalities with smaller inhabitants, indicating that the population increase in municipalities increases the demand for education. Research Implications: Thus, based on technical efficiency analyses, public policies can be proposed that mitigate the deficiencies presented in elementary education. Originality/Value: This study contributes to the literature by estimating the efficiency of municipalities in terms of public spending on education and the efficiency results are the grades of public school students. The research introduces a new output to measure efficiency, and points to new evidence for public educational policies.

Subgrid scale modeling of droplet bag breakup in VOF simulations

The mesh-dependency of the breakup of liquid films, including their breakup length scales and resulting drop size distributions, has long been an obstacle inhibiting the computational modeling of large-scale spray systems. With the aim of overcoming this barrier, this work presents a framework for the prediction and modeling of subgrid-thickness liquid film formation and breakup within two-phase simulations using the volume of fluid method. A two-plane interface reconstruction is used to capture the development of liquid films as their thickness decreases below the mesh size. The breakup of the film is predicted with a semi-analytical model that incorporates the film geometry captured through the two-plane reconstruction. The framework is validated against experiments of the bag breakup of a liquid drop at We=13.8 through the comparison of the resulting drop size and velocity distributions. The generated distributions show good agreement with experimental results for drop resolutions as low as 25.6 cells across the initial diameter. The presented framework enables these drop breakup simulations to be performed at a computational cost three orders of magnitude lower than the cost of simulations utilizing adaptive mesh refinement.

Competing with autonomous model vehicles: a software stack for driving in smart city environments

This article introduces an open-source software stack designed for autonomous 1:10 scale model vehicles. Initially developed for the Bosch Future Mobility Challenge (BFMC) student competition, this versatile software stack is applicable to a variety of autonomous driving competitions. The stack comprises perception, planning, and control modules, each essential for precise and reliable scene understanding in complex environments such as a miniature smart city in the context of BFMC. Given the limited computing power of model vehicles and the necessity for low-latency real-time applications, the stack is implemented in C++, employs YOLO Version 5 s for environmental perception, and leverages the state-of-the-art Robot Operating System (ROS) for inter-process communication. We believe that this article and the accompanying open-source software will be a valuable resource for future teams participating in autonomous driving student competitions. Our work can serve as a foundational tool for novice teams and a reference for more experienced participants. The code and data are publicly available on GitHub.

Gambaran Resiliensi Akademik Mahasiswa Kelas Internasional dan Implikasinya dalam Pelayanan Konseling

This research is motivated by the number of students who have low academic resilience, this is caused by students not believing in their abilities, not being able to control themselves etc. The purpose of this study is to describe: 1) academic resilience of international class students, 2) academic resilience of international class students in terms of confidence (self belief), 3) academic resilience of international class students in terms of control (a sense of control), 4) academic resilience of international class students in terms of composure (anxiety), 5) academic resilience of international class students in terms of commitment (persistence). This research uses quantitative methods with a descriptive approach. The research sample was 72 international class students of the Guidance and Counseling Department of Padang State University who were selected using the total sampling technique. Data obtained by giving a research questionnaire in the form of an academic resilience instrument with a Likert scale model to students who have been tested for validity and data processing using descriptive statistical methods. The results showed that the academic resilience of international class students of BK UNP was generally in the high category with a percentage of (47%).

Experimental Fitting of Efficiency Hill Chart for Kaplan Hydraulic Turbine

The development of hydroelectric technology and much of the “knowledge” on hydraulic phenomena derive from scale modeling and “bench” tests to improve machinery efficiency. The result of these experimental tests is mapping the so-called “hill chart”, representing the “DNA” of a turbine model. Identifying the efficiency values as a function of the specific parameters of the flow and energy coefficient (which both identify the operating point) allows us to represent the complete behavior of a turbine in hydraulic similarity with the original model developed in the laboratory. The present work carries out a “reverse engineering” operation that leads to the definition of “an innovative research model” that is relatively simple to use in every field. Thus, from the experimental survey of the degree of efficiency of several prototypes of machines deriving from the same starting model, the hill chart of the hydraulic profile used is reconstructed. The “mapping” of all the characteristic quantities of the machine, together with the physical parameters of the regulating organs of a four-blade Kaplan turbine model, also made it possible to complete the process, allowing to identify not only the iso-efficiency regions but also the curves relating to the trend of the angle of the impeller blades, the specific opening of the distributor, and the identification of critical areas of cavitation. The development of the hill chart was made possible by investigating the behavior of 33 actual prototypes and 46 characteristic curves derived from the same reference model based on practical experiments for finding the optimal blade distributor “setup curve”. To complete this, theoretical characteristic curves of “not physically realized” prototypes were also mapped, allowing us to complete the regions comprising the diagram. The study of the unified hill charts found in previous documentation of the most famous manufacturers was of great help. Finally, the validation of the “proposed procedure” was obtained through the experimental survey of the actual efficiency of the new prototype based on the theoretical values defined in the design phase on the chart obtained with the method described.

Research and Application of Geomechanical Model Test Technology

Geomechanical model test is one of the commonly used experimental methods in the study of slope stability. It constructs the scale model of slope, simulates the geological environment and load, and carries out the corresponding load experiment to study the stability of slope and its influencing factors. This paper introduces the principles and characteristics of geomechanical model test from the aspects of similar principle, model material selection and key simulation technology.