scholarly journals Cast Structure in Alloy A286, an Iron-Nickel Based Superalloy

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 711 ◽  
Author(s):  
Frisk ◽  
Andersson ◽  
Rogberg
Keyword(s):  
Mathematical Model ◽  
Pore Formation ◽  
Hot Ductility ◽  
Central Section ◽  
Cross Sectional ◽  
Equiaxed Zone ◽  
Nickel Based Superalloy ◽  
Central Porosity ◽  
Continuously Cast ◽  
Iron Nickel

The structure and segregation of a continuously cast iron-nickel based superalloy were investigated. Cross-sectional samples were prepared from the central section of a 150 × 150 mm square billet. The microporosity was measured from the surface to the center and theoretical conditions for pore formation were investigated. A central porosity, up to 10 mm in width, was present in the center of the billet. The measured secondary arm spacing was correlated with a calculated cooling rate and a mathematical model was obtained. Spinel particles were found in the structure, which acted as inoculation points for primary austenite and promoted the formation of the central equiaxed zone. Titanium segregated severely in the interdendritic areas and an increase of Ti most likely lead to a significant decrease in the hot ductility. Precipitates were detected in an area fraction of approximately 0.55% across the billet, which were identified as Ti(CN), TiN, η-Ni3Ti, and a phosphide phase.

Validation of mathematical model of electrothermal calculation of DC catenary on the basis of scale model

2018 ◽  
Vol 77 (4) ◽  
pp. 222-229 ◽  
Author(s):  
A. V. Paranin ◽  
A. B. Batrashov
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Scale Model ◽  
Contact Network ◽  
Scaled Model ◽  
Cross Sectional ◽  
Current Collection ◽  
Topological Features ◽  
Study Results ◽  
Real Physical Process

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

scholarly journals METHODS OF FORMULATING AND SOLVING OPTIMIZATION PROBLEMS OF CUTTING LOGS OF LARGE SIZE BY BAR-SAWING METHOD WITH CUTTING OUT ONE BAR AND FIVE PAIRS OF SIDE EDGING BOARDS WITH SUBSEQUENT SAWING LUMBER FOR EDGED BOARDS

2017 ◽  
Vol 7 (1) ◽  
pp. 137-150
Author(s):  
Агапов ◽  
Aleksandr Agapov
Keyword(s):  
Mathematical Model ◽  
Objective Function ◽  
Optimization Problem ◽  
Optimization Problems ◽  
Target Function ◽  
Cross Sectional ◽  
Optimization Task ◽  
Cutting Out ◽  
The Mathematical Model ◽  
The Relationship

For the first time the mathematical model of task optimization for this scheme of cutting logs, including the objective function and six equations of connection. The article discusses Pythagorean area of the logs. Therefore, the target function is represented as the sum of the cross-sectional areas of edging boards. Equation of the relationship represents the relationship of the diameter of the logs in the vertex end with the size of the resulting edging boards. This relationship is described through the use of the Pythagorean Theorem. Such a representation of the mathematical model of optimization task is considered a classic one. However, the solution of this mathematical model by the classic method is proved to be problematic. For the solution of the mathematical model we used the method of Lagrange multipliers. Solution algorithm to determine the optimal dimensions of the beams and side edging boards taking into account the width of cut is suggested. Using a numerical method, optimal dimensions of the beams and planks are determined, in which the objective function takes the maximum value. It turned out that with the increase of the width of the cut, thickness of the beam increases and the dimensions of the side edging boards reduce. Dimensions of the extreme side planks to increase the width of cut is reduced to a greater extent than the side boards, which are located closer to the center of the log. The algorithm for solving the optimization problem is recommended to use for calculation and preparation of sawing schedule in the design and operation of sawmill lines for timber production. When using the proposed algorithm for solving the optimization problem the output of lumber can be increased to 3-5 %.

A mathematical model for calculating cross-sectional properties of modern wind turbine composite blades

2014 ◽  
Vol 64 ◽  
pp. 52-60 ◽  
Author(s):  
Lin Wang ◽  
Xiongwei Liu ◽  
Lianggang Guo ◽  
Nathalie Renevier ◽  
Matthew Stables
Keyword(s):  
Mathematical Model ◽  
Wind Turbine ◽  
Cross Sectional ◽  
Composite Blades

scholarly journals Formation of Annual Ring Eccentricity in Coarse Roots within the Root Cage of Pinus ponderosa Growing on Slopes

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 181 ◽  
Author(s):  
Antonio Montagnoli ◽  
Bruno Lasserre ◽  
Gabriella Sferra ◽  
Donato Chiatante ◽  
Gabriella Stefania Scippa ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Root System ◽  
Pinus Ponderosa ◽  
Cross Sectional Area ◽  
Root Segment ◽  
Mechanical Forces ◽  
Sectional Area ◽  
Coarse Roots ◽  
Cross Sectional ◽  
Branching Point

The coarse roots of Pinus ponderosa included in the cage are the ones most involved in tree stability. This study explored the variations in traits, such as volume, cross-sectional area, and radius length of cage roots, and used those data to develop a mathematical model to better understand the type of forces occurring for each shallow lateral root segment belonging to different quadrants of the three-dimensional (3D) root system architecture. The pattern and intensity of these forces were modelled along the root segment from the branching point to the cage edge. Data of root cage volume in the upper 30 cm of soil showed a higher value in the downslope and windward quadrant while, at a deeper soil depth (>30 cm), we found higher values in both upslope and leeward quadrants. The analysis of radius length and the cross-sectional area of the shallow lateral roots revealed the presence of a considerable degree of eccentricity of the annual rings at the branching point and at the cage edge. This eccentricity is due to the formation of compression wood, and the eccentricity changes from the top portion at the branching point to the bottom portion at the cage edge, which we hypothesize may be a response to the variation in mechanical forces occurring in the various zones of the cage. This hypothesis is supported by a mathematical model that shows how the pattern and intensity of different types of mechanical forces are present within the various quadrants of the same root system from the taproot to the cage edge.

Experimental Study on the Surface Roughness in Mesoscopic-Scale Grinding of Nickel-Based Superalloy

2016 ◽  
Vol 1136 ◽  
pp. 9-14
Author(s):  
Yun Guang Zhou ◽  
Ya Dong Gong ◽  
Yang Sun ◽  
Zhong Xiao Zhu ◽  
Qi Gao
Keyword(s):  
Mathematical Model ◽  
Surface Roughness ◽  
Feed Rate ◽  
Theoretical Basis ◽  
Spindle Speed ◽  
Range Analysis ◽  
Mesoscopic Scale ◽  
Nickel Based Superalloy ◽  
Grinding Parameters ◽  
Grinding Tool

This paper uses micro-grinding tool with 500# grains and 0.9 mm diameter to grind nickel-based superalloy Inconel600 through three factors(grinding depth, feed rate, spindle speed ) at three levels orthogonal grinding experiment in mesoscopic scale. Then according to the range analysis of surface roughness, the primary and secondary influencial factors are found; the micro grinding parameters are optimized ,the results show: the influence of the feed rate(vf)is the biggest, followed by the spindle speed(n), the grinding depth(ap) is minimal, when n=50kr/min, vf=100μm/s, ap=6μm, the grinding surface roughness is minimum: Ra=579nm; finally , the regression mathematical model of micro grinding surface roughness is established, the relative error of the calculated value and experimental measurements is low, showing that this regression mathematical model is accurate and effective. This study provides a theoretical basis for the micro grinding parameters and surface quality control of nickel-based superally.

On the Relationship between Inclusions and Pores, Part II: Dendritic Structure, Pressure Drop in the Liquid and Pore Precipitation

2014 ◽  
Vol 790-791 ◽  
pp. 302-307 ◽  
Author(s):  
Arash Safavi Nick ◽  
Hasse Fredriksson
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Pore Formation ◽  
Pressure Field ◽  
Primary Dendrite ◽  
Dendritic Structure ◽  
Steel Sample ◽  
Continuously Cast ◽  
The Relationship ◽  
Scanning Electron

There is a relationship between pores and inclusions. As hypothesis goes, inclusions have an affinity to gather inside the pores and form clusters. Focus of this paper is how solidified dendritic structure affects the pressure field in the liquid and pore precipitation in austenitic stainless steel. Steel sample is a continuously cast bloom. Temperature profile and width of the mushy zone of the strand is modeled according to a constant temperature at the strands surface. Thermal analysis has been performed with differential thermal analysis (DTA) and differential scanning calorimeter (DSC). Dendrite arm spacing (DAS) is measured with light optical microscopy (LOM) and scanning electron microscopy (SEM). DAS is represented as the weight average of the distance between parallel sets of primary dendrite stems. Pressure field is calculated based on Darcys law. Pore formation is described through segregation of the gas components and pressure field in the liquid.

scholarly journals Application of an Improved Mathematical Model to the Analysis of Cross-Sectional EBIC of GaN-Based LEDs

2006 ◽  
Vol 12 (S02) ◽  
pp. 752-753
Author(s):  
CM Parish ◽  
CL Progl ◽  
AD Batchelor ◽  
PE Russell
Keyword(s):  
Mathematical Model ◽  
Cross Sectional

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005

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