scholarly journals A comparison of Lagrangian/Eulerian approaches for tracking the kinematics of high deformation solid motion.

2009 ◽  
Author(s):  
Thomas L. Ames ◽  
Grant V. Farnsworth ◽  
David Isaac Ketcheson ◽  
Allen Conrad Robinson
Chromosoma ◽  
2021 ◽  
Vol 130 (1) ◽  
pp. 27-40
Author(s):  
Guoqing Liu ◽  
Hongyu Zhao ◽  
Hu Meng ◽  
Yongqiang Xing ◽  
Lu Cai

AbstractWe present a deformation energy model for predicting nucleosome positioning, in which a position-dependent structural parameter set derived from crystal structures of nucleosomes was used to calculate the DNA deformation energy. The model is successful in predicting nucleosome occupancy genome-wide in budding yeast, nucleosome free energy, and rotational positioning of nucleosomes. Our model also indicates that the genomic regions underlying the MNase-sensitive nucleosomes in budding yeast have high deformation energy and, consequently, low nucleosome-forming ability, while the MNase-sensitive non-histone particles are characterized by much lower DNA deformation energy and high nucleosome preference. In addition, we also revealed that remodelers, SNF2 and RSC8, are likely to act in chromatin remodeling by binding to broad nucleosome-depleted regions that are intrinsically favorable for nucleosome positioning. Our data support the important role of position-dependent physical properties of DNA in nucleosome positioning.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 803
Author(s):  
Bernd-Arno Behrens ◽  
Johanna Uhe ◽  
Tom Petersen ◽  
Christian Klose ◽  
Susanne E. Thürer ◽  
...  

The current study introduces a method for manufacturing steel–aluminum bearing bushings by compound forging. To study the process, cylindrical bimetal workpieces consisting of steel AISI 4820 (1.7147, 20MnCr5) in the internal diameter and aluminum 6082 (3.2315, AlSi1MgMn) in the external diameter were used. The forming of compounds consisting of dissimilar materials is challenging due to their different thermophysical and mechanical properties. The specific heating concept discussed in this article was developed in order to achieve sufficient formability for both materials simultaneously. By means of tailored heating, the bimetal workpieces were successfully formed to a bearing bushing geometry using two different strategies with different heating durations. A metallurgical bond without any forging defects, e.g., gaps and cracks, was observed in areas of high deformation. The steel–aluminum interface was subsequently examined by optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It was found that the examined forming process, which utilized steel–aluminum workpieces having no metallurgical bond prior to forming, led to the formation of insular intermetallic phases along the joining zone with a maximum thickness of approximately 5–7 µm. The results of the EDS analysis indicated a prevailing FexAly phase in the resulting intermetallic layer.


2021 ◽  
Vol 10 (3) ◽  
pp. 119
Author(s):  
Hakan A. Nefeslioglu ◽  
Beste Tavus ◽  
Melahat Er ◽  
Gamze Ertugrul ◽  
Aybuke Ozdemir ◽  
...  

Suitable route determination for linear engineering structures is a fundamental problem in engineering geology. Rapid evaluation of alternative routes is essential, and novel approaches are indispensable. This study aims to integrate various InSAR (Interferometric Synthetic Aperture Radar) techniques for sinkhole susceptibility mapping in the Kirikkale-Delice Region of Turkey, in which sinkhole formations have been observed in evaporitic units and a high-speed train railway route has been planned. Nine months (2019–2020) of ground deformations were determined using data from the European Space Agency’s (ESA) Sentinel-1A/1B satellites. A sinkhole inventory was prepared manually using satellite optical imagery and employed in an ANN (Artificial Neural Network) model with topographic conditioning factors derived from InSAR digital elevation models (DEMs) and morphological lineaments. The results indicate that high deformation areas on the vertical displacement map and sinkhole-prone areas on the sinkhole susceptibility map (SSM) almost coincide. InSAR techniques are useful for long-term deformation monitoring and can be successfully associated in sinkhole susceptibility mapping using an ANN. Continuous monitoring is recommended for existing sinkholes and highly susceptible areas, and SSMs should be updated with new results. Up-to-date SSMs are crucial for the route selection, planning, and construction of important transportation elements, as well as settlement site selection, in such regions.


2021 ◽  
pp. 1-18
Author(s):  
Xin Li ◽  
Jie Zhang ◽  
Cuinan Li ◽  
Weilin Chen ◽  
Jingbin He ◽  
...  

Abstract The borehole stability of the coalbed methane (CBM) well has always been vital in deep CBM exploration and development. The borehole instability of the deep CBM well is due to many complicated reasons. The change in the surrounding rock temperature is an important and easily overlooked factor among many reasons. In this research, we used methods that include experiment and numerical simulation to study the characteristic law of the borehole deformation induced by the changes in the surrounding rock temperature of deep CBM well. The experimental results of the stress–strain curves of five sets of experiments show that when the experimental temperature rises from 40 °C to 100 °C, the average stress when coal samples are broken gradually decreases from 81.09 MPa to 72.71 MPa. The proportion of plastic deformation in the entire deformation stage gradually increases from 7.8% to 25.7%. Moreover, the characteristics that some key mechanical parameters of coal samples change with the experimental temperature are fitted, and results show that as the experimental temperature rises from 40 °C to 100 °C, the compressive strength, elastic modulus, and main crack length of coal samples show a gradually decreasing trend. By contrast, the Pois-son's ratio and primary fracture angle show a gradually increasing trend. Moreover, the relativity of the linear equations obtained by fitting is all close to 1, which can accurately reflect the corresponding change trend. Numerical simulation results show that a high temperature of the surrounding rock of the deep CBM well results in a high range of stress concentration on the coal seam borehole and high deformation.


Author(s):  
P.A. Radchenko ◽  
◽  
S.P. Batuev ◽  
A.V. Radchenko ◽  
◽  
...  

The fracture of high-strength impactor in interaction with a steel barrier is investigated. Three typesof head parts of the impactor are considered: flat, hemispherical and ogival. Normal and oblique interactions with velocities of 700 and 1000 m/s are investigated. Modeling is carried out by the finite element method in a three-dimensional formulation using the author's software EFES 2.0.The limit value of intensity of plastic deformations is used as a fracture criterion. The influence of the striker head part shape, interaction velocity, interaction angle on the fracture of the impactor and the barrier has been investigated. Conditions under which the striker ricochets were defined.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sourabh Shukla ◽  
Awanikumar P. Patil ◽  
Ashlesha Kawale ◽  
Anand Babu Kotta ◽  
Inayat Ullah

Purpose Effect of grain size on degree of sensitization (DOS) was been evaluated in Nickel free steel. Manganese and nitrogen contained alloy is a Ni-free austenitic stainless steels (ASS) having type 202 grade. The main purpose of this investigation is to find the effect of recrystallization on the DOS of stainless steel after the thermo-mechanical processing (cold work and thermal aging). Design/methodology/approach In the present investigation, the deformation of 202 grade analyzed using X-ray diffraction (XRD) and microstructural testing. Optical microstructure of Ni-free ASS has been done for cold worked samples with thermally aged at 900°C_6 h. Double loop electrochemical potentiodynamic reactivation test used for findings of degree of sensitization. Findings Ni-free ASS appears to be deformed more rapidly due to its higher stacking fault energy which gave results in rapid transformation from strain induced martensite to austenite in form of recrystallized grains, i.e. it concluded that as cold work percentage increases more rapidly recrystallization occurs. XRD results also indicate that more fraction of martensite formed as percentage of CW increases but as thermal aging reverted those all martensite to austenite. So investigation gives the conclusion which suggests that with high deformation at higher temperature and duration gives very less DOS. Originality/value Various literatures available for 300 series steel related to the effect of cold work on mechanical properties and sensitization mechanism. However, no one has investigated the effect of recrystallization through thermomechanical processing on the sensitization of nickel-free steel.


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