Deformations In Vertical Direction Research Articles

Accurate 3D morphological computational model reconstruction of suspended cells imaged through stratified media by the precise depth-varying point spread function method.

Accurate three-dimensional (3D) morphological computational models of cells are important in a number of biological studies. This study proposes a precise depth-varying point spread function (PDV-PSF) method for reconstructing 3D computational models of suspended cells from two-dimensional (2D) confocal image stacks. Our approach deblurs the 2D images in horizontal plane and corrects the deformation in vertical direction to overcome the refractive index mismatch problem caused by suspended cells imaging through stratified media. Standard fluorescent polystyrene spheres and Jurkat T-lymphocytes are selected to evaluate the validity and accuracy of this PDV-PSF method. Qualitative and quantitative results demonstrate that our approach has superior performance in 3D morphological computational models reconstruction of suspended cells.

Development and testing of a wireless multi-axis toolholder dynamometer for milling and drilling process

The cutting force provides important information such as tool condition, chips information, and machining parameters selection. Thus, many researchers have proposed some methods for cutting force monitoring. However, most of them are only applied in the laboratory due to lower flexibility and complex installation. In this paper, a split multi-axis toolholder dynamometer is proposed and developed, which can equip different types of machining spindle and fit for multi-size tool. It consists of six capacitive sensors that can sense four deformations in vertical direction and two deformations in circumferential direction. Meanwhile, the distance between two plates in the vertical and circumferential capacitive sensors was adjusted separately. An acquisition and wireless transmission unit was designed to detect the capacitive variation and then transfer data to upper computer. Finally, a standard tool holder and a force sensing unit, a bottom socket, an acquisition and wireless transmission unit, a lithium battery, a cover were installed and debugged as a whole system. To validate its static and dynamic characteristics, various tests are conducted. The result demonstrates that the toolholder dynamometer can accurately and reliably monitor four-axis cutting force in the milling and drilling operations.

Comparative analysis of reactor pressure vessel failure using two thermo-fluid-structure coupling approaches

Reactor pressure vessel (RPV) failure analysis is a thermo-fluid-structure coupled problem involving the melt pool heat transfer and RPV structural failure. It is of great importance to the qualification of severe accident mitigation strategies as well as the general assessment of severe accident risk in light water reactors. Two coupling approaches, i.e. volume loads mapping (VLM) and surface loads mapping (SLM), are widely employed to resolve this problem. The present study was intended to compare the performance of the two coupling approaches by simulating vessel failure problems of the FOREVER-EC2 experiment and a reference boiling water reactor (BWR) during a postulated severe accident. Simulations of the experiment using the two different approaches showed good agreements with experimental data in terms of total deformation in vertical direction of bottom point and wall thickness changes. The spatial distributions of creep strain and total deformation were also similar between the two approaches. For the reference BWR case, good agreements were achieved between the two approaches in predicting the maximum creep strain and the total deformation in vertical direction of bottom point. The deformation rate of the vessel wall was slow at the beginning, and then increased with time, and finally accelerated to a drastic deformation prior to vessel failure. Similar spatial distributions of creep strain and total deformation were also predicted by the two approaches. Although the SLM approach predicted the deformation acceleration began slightly earlier than the VLM, the difference between the predicted failure times was negligible if considering the very long vessel failure time (~104s) and various uncertainties. Generally speaking, the VLM approach was computationally more efficient than the SLM, while both approaches had similar performances in terms of their predictability of experiment and applicability to reactor case.

A Comparison of Negative Compressibility between 3D Cellular Models Constructed by 2D Hinging Wine‐Rack and Hexagonal Honeycomb Mechanisms

Herein, two kinds of 3D hexagonal honeycomb equivalent models are proposed, enlightened by the octahedron model constructed by the wine‐rack mechanism. They differ in their unit‐cell arrangement forms, which are array and homogeneous arrangements, respectively. Referring to the analysis of the octahedron model, the expressions of compressibility properties of the two new models are given and the conditions for obtaining negative compressibility are analyzed. Comparing these two models with the octahedron model, it is found that although the three models are quite different in externality, they have similar mechanical properties (Young's modulus, Poisson's ratio, and compressibility), and all have image symmetry in both horizontal directions. Further analysis shows that these three models are so unified that they can be expressed by a more general model, from which another model with negative compressibility can be deduced. Finally, a new method to improve negative compressibility property is concluded from comparing the three models, that is, increasing the number or length of rods without deformation in vertical direction can effectively improve negative compressibility property in this direction and weaken negative compressibility property in the other two directions.

Deformation mechanism of the Cryostat in the CADS Injector II

Thermal contraction and expansion of the Cryostat will affect its reliability and stability. To optimize and upgrade the Cryostat, we analyzed the heat transfer in a cryo-vacuum environment from the theoretical point first. The simulation of cryo-vacuum deformation based on a finite element method was implemented respectively. The completed measurement based on a Laser Tracker and a Micro Alignment Telescope was conducted to verify its correctness. The monitored deformations were consistent with the simulated ones. After the predictable deformations in vertical direction have been compensated, the superconducting solenoids and Half Wave Resonator cavities approached the ideal “zero” position under liquid helium conditions. These guaranteed the success of 25 MeV@170 uA continuous wave protons of Chinese accelerator driven subcritical system Injector II. By correlating the vacuum and cryo-deformation, we have demonstrated that the complete deformation was the superposition effect of the atmospheric pressure, gravity and thermal stress during both the process of cooling down and warming up. The results will benefit to an optimization for future Cryostat’s design.

리브플러스 PC슬래브의 수평전단강도 평가

본 연구는 PC와 RC부분이 만나는 접합면에 대한 구조적 거동과 수평 전단강도 평가를 위한 실험적 연구이다. 접합면에서의 수평전단 내력은 접합면의 거칠기나 전단보강근 유무에 따라 결정되어진다. 본 연구에서는 전단 보강근의 형상이 루프형과 래티스형로 구분하고, 보강근 간격 등에 따라 총 4개의 수평전단강도 실험체를 제작하여 실험을 수행하였다. 실험결과, 접합면에서 수평전단 강도는 수직방향 변형에 의해 지배됨을 알 수 있었다. 보강근 형상에 따른 비교 결과, 루프형의 실험체가 평균 초기균열하중, 평균 최대하중 및 접합면의 평균 초기강성 측면에서 각각 33.7%, 45.9%와 55.2%정도 큰 것으로 나타났다. 현행의 국내 전단강도 평가식과 비교한 결과, 루프형 전단보강 실험체는 2.32~4.23배, 래티스형 전단보강 실험체는 1.65~3.06배 상회하는 것으로 나타났다. 따라서 접합면의 거동이나 구조설계기준에 의한 내력이 안전측으로 평가되어 현장에 적용하는 데에는 별다른 문제는 없는 것으로 판단된다. This study investigates the horizontal shear behavior of an interface between precast concrete (PC) and topping concrete(RC), and evaluates the horizontal based on the investigations by the experimental. Horizontal shear strength in connected surface is determined by the roughness an interface and the shear reinforcement or not. In this study, the main experimental parameters are the shear reinforcement types in the shape of loop-type and lattice-type, rebar spacing. A total of four specimens were shear strength tested and manufactured. As a result, the horizontal shear strength of reinforced connected surface was found to be controlled by deformation in vertical direction. Comparison of reinforcement shape, the mean initial crack load loop type specimens, the average maximum load and the junction of the average in terms of initial stiffness, respectively 33.7%, 45.9% and 55.2% were large enough. Evaluation results for shear strength equation of existing standard domestic, the loop-type reinforced 2.32 to 4.23 times, lattice-type reinforced 1.65 to 3.06 times appears to be higher. Behavior of interface or strength of structural design criteria was fairly safe side. It does not have any problems in the applied field is considered.