Non-invasive optical characterization and estimation of Zn porosity in gas tungsten arc welding of Fe–Al joints using CR model and OES measurements

In this study,we employed a non-invasive approach based on the collisional radiative(CR)model and optical emission spectroscopy(OES)measurements for the characterization of gas tungsten arc welding(GTAW)discharge and quantification of Zn-induced porosity during the GTAW process of Fe–Al joints.The OES measurements were recorded as a function of weld current,welding speed,and input waveform.The OES measurements revealed significant line emissions from Zn-I in 460–640 nm and Ar-I in 680–800 nm wavelength ranges in all experimental settings.The OES coupled CR model approach for Zn-I line emission enabled the simultaneous determination of both essential discharge parameters i.e.electron temperature and electron density.Further,these predictions were used to estimate the Zn-induced porosity using OES-actinometry on Zn-I emission lines using Ar as actinometer gas.The OES-actinometry results were in good agreement with porosity data derived from an independent approach,i.e.x-ray radiography images.The current study shows that OES-based techniques can provide an efficient route for real-time monitoring of weld quality and estimate porosity during the GTAW process of dissimilar metal joints.

An Innovative Finite Element Geometric Modeling of Single-Layer Multi-Bead WAAMed Part

Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead profilegeometric modeling method through the isosceles trapezoid function is proposed to build the FE model of theWAAMprocess. Firstly, a straight-line model for overlapping beads based on the parabola function was establishedto calculate the optimal center distance. Then, the isosceles trapezoid-based profile was employed to replace theparabola profiles of the parabola-based overlapping model to establish an innovative isosceles trapezoid-basedmulti-bead overlapping geometric model. The rationality of the isosceles trapezoid-based overlapping model wasconfirmed by comparing the geometric deviation and the heat dissipation performance index of the two overlappingmodels. In addition, the FE-coupled thermal-mechanical analysis, as well as a comparative experiment of thesingle-layer eight-bead deposition process show that the simulation results of the above two models agree with theexperimental results. At the same time, the proposed isosceles trapezoid-based overlappingmodels are all straightlineprofiles, which can be divided into high-quality FE elements. It can improve the modeling efficiency andshorten the simulation calculation time. The innovative modeling method proposed in this study can provide anefficient and high-precision geometricmodelingmethod forWAAMpart FE coupled thermal-mechanical analysis.

Tidal modeling based on satellite altimetry observations of TOPEX/ Poseidon, Jason1, Jason2, and Jason3 with high prediction capability: A case study of the Baltic Sea

This research aims to optimize the utilization of long-term sea level data from the TOPEX/Poseidon,Jason1,Jason2,and Jason3 altimetry missions for tidal modeling.We generate a time series of along-track observations and apply a developed method to produce tidal models with specific tidal constituents for each location.Our tidal modeling methodology follows an iterative process:partitioning sea surface height(SSH)observations into analysis/training and prediction/validation parts and ultimately identi-fying the set of tidal constituents that provide the best predictions at each time series location.The study focuses on developing 1256 time series along the altimetry tracks over the Baltic Sea,each with its own set of tidal constituents.Verification of the developed tidal models against the sSH observations within the prediction/validation part reveals mean absolute error(MAE)values ranging from 0.0334 m to 0.1349 m,with an average MAE of 0.089 m.The same validation process is conducted on the FES2014 and EOT20 global tidal models,demonstrating that our tidal model,referred to as BT23(short for Baltic Tide 2023),outperforms both models with an average MAE improvement of 0.0417 m and 0.0346 m,respectively.In addition to providing details on the development of the time series and the tidal modeling procedure,we offer the 1256 along-track time series and their associated tidal models as supplementary materials.We encourage the satellite altimetry community to utilize these resources for further research and applications.

基于混合FE-SEA法的箱梁结构噪声特性研究

为探讨箱梁结构噪声规律及其影响因素,以南昌某高架铁路箱梁为研究对象,建立混合FE-SEA模型进行数值仿真分析,并进行现场试验验证。在此基础上,探讨了板厚对结构噪声的影响规律,分析了箱梁各子系统对远场声压的声贡献量。研究结果表明:混合FE-SEA法适用于箱梁结构噪声研究;箱梁结构振动的峰值频率为125 Hz,结构噪声频率范围为50~160 Hz;箱梁顶板和翼板对远场声压级的贡献量较大:增加各板厚度能降低结构噪声,其中增加顶板厚度效果较为明显。因此在减振降噪的过程中,应着重关注顶板和翼板。

GRMP协议中的FEModel在Linux下的实现

GRMP(GeneralRouterManagementProtocol)协议是用于转发和控制单元分离(ForwardingandControlElementSeparation,ForCES)的路由器管理协议。该文介绍了如何利用Linux2.4内核中的模块、软中断、Netfilter等来实现GRMP协议模型中的转发单元模型(ForwardingElementModel,FEModel)。

Kinetics and Modeling of Chemical Leaching of Sphalerite Concentrate Using Ferric Iron in a Redox-controlled Reactor

This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical leaching of sphalerite were investigated. The shrinking core model was applied to analyze the experimental results. It was found that both the Fe3+ concentration and the redox potential controlled the chemical leaching rate of sphalerite. A new kinetic model was developed, in which the chemical leaching rate of sphalerite was proportional to Fe3+ concentration and Fe3+ /Fe2+ ratio. All the model parameters were evaluated from the experimental data. The model predictions fit well with the experimental observed values.

Vacancies and Antisites in B2 FeAl and DO_3 Fe_3Al with a Modified Analytic EAM Model

A simple modified analytic EAM model for bcc Fe and fcc Al was used to calculate the lattice constant and elastic constants of B2 FeAl and DO3 Fe3Al alloys. The formation energies of vacancy and antisite were also calculated. The present calculations are in agreement with the experimental data and the theoretical results obtained by other authors.

Comparison of wear behavior of ABS and Nylon6-Fe powder composite parts prepared with fused deposition modelling

Fused deposition modeling(FDM) is one of the latest rapid prototyping techniques in which parts can be manufactured at a fast pace and are manufactured with a high accuracy. This research work is carried out to study the friction and wear behavior of parts made of newly developed Nylon6-Fe composite material by FDM. This work also involves the comparison of the friction and wear characteristics of the Nylon6-Fe composite with the existing acrylonitrile butadiene styrene(ABS) filament of the FDM machine. This Is carried out on the pin on disk setup by varying the load(5, 10, 15 and 20 N) and speed(200 and 300 r/min). It is concluded that the newly developed composite is highly wear resistant and can be used in industrial applications where wear resistance is of paramount importance. Morphology of the surface in contact with the Nylon6-Fe composite and ABS is also carried out.

Numerical model of solidification process in binary Al Fe alloy under centrifugal casting

During the solidification process of binary Al Fe alloy under centrifugal casting, the primary phase of Al 3Fe migrates along the radius because of the density difference between the primary phase and the liquid alloy. Therefore the temperature and concentration field are affected significantly by both the fluid flow and the solid phase migration. In order to take this factor into consideration, a two phase flow numerical model has been established in column coordinate to depict the solidification process of Al Fe alloy under centrifugal casting according to the feature that there exists the solid phase migration during the process. Thus the solidification process of Al Fe alloy under centrifugal casting has been described much more pertinently. [

Numerical modelling of microstructure forming process for Al-Al_3Fe eutectic alloy

A self adjusting model was presented on the basis of the effect of temperature gradient on eutectic growth and a curved solid/liquid interface. Finite differential method was adopted to solve the model. The average lamellar spacing of the Al Al 3Fe eutectic alloy and the content fields ahead of the solidifying interface under different growth rates were calculated. Directional solidification experiments were carried out in order to prove the modification of the modeling. The experimental results are in relatively good agreement with the calculations.

A three-dimensional model for the transportation of Fe and Mn in Arha Reservoir

Coupling with a three dimensional (3D) hydrodynamic model and a suspended solids model, a 3D model for the transport of Fe and Mn in Arha Reservoir, China, was developed. The 3D velocity fields for the flood season are computed to drive the 3D model of Fe and Mn in which the processes of advection, diffusion, redox, sorption, desorption, deposition, and re suspension are included. The model has been calibrated by matching observed fluid, suspended solids, and total concentrations of Fe and Mn in the water column and in the sediment, successively. The model simulated both horizontal and vertical gradients of Fe and Mn in Arha Reservoir. It was found that Fe and especially Mn stratify in accordance with the stratification of DO during summer. The redox cycles across the water sediment interface has a principal role in the rise of Fe and Mn concentrations in the overlying water. It was also found that Fe and Mn loadings from the tributaries have a carryover effect on the water quality through a secondary contamination in the reservoir.

EFFECT OF SHS PARAMETERS OF Ni0.35Zn0.65Fe2O4 FERRITE ON MAGNETIC PROPERTIES AND ESTABLISHMENT OF MATHEMATICAL MODEL

Ni0.35Zn0.65Fe2O4 ferrite was synthesized by SHS method. In the process of SHS, combustion temperature and velocity were the main process parameters , which were decided by the Fe content, grain size of the ferrite powder, relative density and the oxygen pressure. In this paper the effects of Fe content, grain size and oxygen pressure on combustion temperature and velocity were discussed. The relation between combustion temperature and magnetic permeability was also studied and the method of polynomial regression was used to establish the mathematical model of the relation.

Evaluation of Component Activities in C-Mn-Fe-Si with Model Self-SReM4

A sub-regular solution model SELFSReM4 used to evaluate activities of the components in a homogeneous region of a quaternary system has been developed in Shanghai Enhanced Lab of Ferrometallurgy. This paper introduces the application of SELFSReM4 in evaluating activities of the components in C-Mn-Fe-Si system without SiC precipitation.

Simplified Thermodynamic Model for Pro-Eutectoid Ferrite Formation in Multicomponent Structural Steel

By introducing aparameter of difference in ferrite formation temperature between binary Fe-C and multicomponent system,and referring to the thermodynamic model for Fe-C binary system,a simplified thermodynamic model for pro-eutectoid ferrite formation in Fe-ΣXiC multicomponent structural steels(Xi=Mn,Si,Mo,Cr,Ni or Ti,etc)was suggested.The comparison of the calculated Ae3 temperatures with the measured data of steels 42 shows that the relative standard deviation and root-mean-square(RMS)error between them are only 0.71% and 8.92 K,respectively.However,the deviations between the same measured data and the values calculated from the superelement model are as high as 1.86% and 23.83 K,respectively.It can be concluded that the simplified thermodynamic model for pro-eutectoid ferrite formation in multicomponent structural steels is acceptable and the calculated Ae3 temperatures are in good agreement with the experimental data.

The Relationship between Fe Mineralization and Magnetic Basement Faults using Multifractal Modeling in the Esfordi and Behabad Areas(BMD), Central Iran

Multifractal modeling is a mathematical method for the separation of a high potential mineralized background from a non-mineralized background. The Concentration-Distance to Fault structures(C-DF) fractal model and the distribution of the known iron(Fe) deposits/mines seen in the Esfordi and Behabad 1:100,000 sheets from the Bafq region of central Iran are used to distinguish Fe mineralization based on their distance to magnetic basement structures and surface faults, separately, using airborne geophysical data and field surveys. Application of the C-DF fractal model for the classification of Fe mineralizations in the Esfordi and Behabad areas reveals that the main ones show a correlation with their distance from magnetic basement structures. Accordingly, the distances of Fe mineralizations with grades of Fe higher than 55%(43% < Fe ≤ 60%) are located at a distance of less than 1 km, whereas for surfacial faults with grades of 43% ≤ Fe ≤ 60%, the distances are 3162< DF ≤ 4365 m from the faults. Thus, there is a positive relationship between Fe mineralization and magnetic basement structures. Also, the proximity evidence of Precambrian high-grade Fe mineralization related to magnetic basement structures indicates syn-rifting tectonic events. Finally, this C-DF fractal model can be used for exploration of magmatic and hydrothermal ore deposits.

Fe-0.1C-5Mn中锰钢热变形行为研究

通过Gleeble-3500热机械模拟机研究了Fe-0.1C-5Mn中锰钢在950~1150℃变形温度、0.001~1 s^(-1)应变速率下的高温变形行为。根据单道次热压缩的真应力-真应变曲线,分析了变形条件对流变应力的影响,发现高温和低应变速率有利于动态再结晶的发生。引入Zener-Hollomon参数,建立本构方程,得到钢的热变形激活能为256.317 kJ/mol。通过对试验数据的拟合,建立了中锰钢动态回复和动态再结晶的分段流变应力模型,结果表明:模型预测值与试验值吻合较好,证明了所建模型的可靠性。

Modelling self-sensing of a magnetostrictive actuator based on a terfenol-D rod

A simplified quasi-static computational model for self-sensing applications of magnetostrictive actuators based on terfenol-D rods is presented. Paths and angle changes in the magnetic moments rotation of Tb0.3Dy0.7Fe2 alloy are studied as functions of compressive stress and magnetic field, and then used to determine the magnetization in its actuation. Then sensing of magnetic induction picked from a driving coil in an actuator is derived. The model is quick and efficient to solve moments rotation and its magnetization. Sensing results of compressive stress and magnetostriction calculated by the model are in good agreement with experiments and will be helpful in the design and control of self-sensing applications in actuators.

Fe-Zn相图不同相区温度合金化锌镀层生长过程模拟

目的 优化GA镀层的成形性能,建立GA镀层物相生长模型,调控镀层物相组成,得出最佳合金化镀层物相组成对应的工艺参数,以指导生产。方法 依据最新的Fe-Zn相图,构建镀层合金化模型,模拟镀层物相η、ζ、δ和Γ生长过程及物相沿镀层截面分布、镀层合金化过程Fe含量变化。结果 成功模拟了Fe-Zn相图不同相区物相的生长过程,模拟530℃以下温度物相转变为η→ζ→δ→Γ,530℃以上温度物相转变为η→δ→Γ。模拟得到最佳镀层物相组成对应的合金化工艺为,510℃保温9.7s,540℃保温6.8s。研究得到了合金化过程中镀层Fe含量的变化规律,在合金化前期,Fe含量增加的速率较快,随着合金化程度的提高,镀层中Fe含量的增加速率减慢。结论 建立的GA镀层物相生长模型可以模拟得到不同合金化温度下最佳的工艺参数,为合金化热处理生产GA镀层提供了工艺参考。

Electronic Structure Effect on Model Cluster for L1_2 Structure of Al_3Ti Intermetallic Compound with an Addition of Alloying Elements Fe, Ni and Cu

By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.

Nd-Fe-B片铸连续恒定浇注流量数学模型分析及工程实现

针对烧结Nd-Fe-B磁体生产过程中速凝(片铸)浇注流量较难控制的问题,建立合金熔炼坩埚连续恒定浇注流量数学模型,用工程软件计算并绘制倾角(θ)-流量(q)、时间(t)-速度(v)等函数曲线;分析函数曲线特征,发现倾转坩埚的几何形貌和状态变化是导致连续浇注流量不稳定的主要因素,在约60°与73.9°倾转角流量发生急剧变化。根据曲线特性和现场采集数据,制定短时间等角速度(即局部线性化)的恒定熔液流量控制策略,设计片铸炉的系统嵌入式间接模糊控制恒定浇注流量铸片子系统,工程化实现浇注过程液面无浪涌的连续平稳片铸,铸片厚度及其一致性均达到满意指标。