Deformation Behaviors and Critical Parameters in Microscale Laser Dynamic Forming

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Huang Gao ◽  
Chang Ye ◽  
Gary J. Cheng
Keyword(s):  
Critical Parameters ◽  
Thin Foils ◽  
Deformation Behaviors ◽  
Microfabrication Technique ◽  
Simulation Results ◽  
Relationship Of ◽  
The Relationship ◽  
Method Model ◽  
Ultrahigh Strain

Microscale laser dynamic forming (μLDF) is a novel microfabrication technique to introduce complex 3D profiles in thin films. This process utilizes pulse laser to generate plasma to induce shockwave pressure into the thin film, which is placed above a microsized mold. The strain rate in μLDF reaches 106–107 S−1. Under these ultrahigh strain rates in microscale, deformation behaviors of materials are very complicated and almost impossible to be measured in situ experimentally. In this paper, a finite element method model is built to simulate the μLDF process. An improved Johnson–Cook model was used to calculate the flow stress, and the Johnson–Cook failure criterion was employed to simulate failure during μLDF. The simulation results are validated by experiments, in which the deformation of Cu thin foils after μLDF experiments are characterized by scanning electron microscopy and compared with simulation results. With the verified model, the ultrafast μLDF process is generally discussed first. A series of numerical simulations are conducted to investigate the effects of critical parameters on deformation behaviors. These critical parameters include the ratio of the fillet radius to film thickness, the aspect ratio of mold, as well as laser intensities. The relationship of laser pulse energy and the deformation depth is also verified by a series of μLDF experiments.

A Novel Trans-Scale Precision Positioning Stage Based on the Stick-Slip Effect

2012 ◽  
Vol 2 (2) ◽  
pp. 1-14 ◽  
Author(s):  
Bowen Zhong ◽  
Liguo Chen ◽  
Zhenhua Wang ◽  
Lining Sun
Keyword(s):  
Friction Model ◽  
Slip Effect ◽  
Precision Positioning ◽  
Stick Slip ◽  
Kinematics Model ◽  
Lugre Friction Model ◽  
Positioning Stage ◽  
Simulation Results ◽  
Relationship Of ◽  
The Relationship

This article focuses on developing a novel trans-scale precision positioning stage based on the stick-slip effect. The stick-slip effect is introduced and the rigid kinematics model of the stick-slip driving is established. The forward and return displacement equations of each step of the stick-slip driving are deduced. The relationship of return displacement and the acceleration produced by friction are obtained according to displacement equations. Combining with LuGre friction model, the flexible dynamics model of the stick-slip driving is established and simulated by using Simulink software. Simulation results show that the backward displacement will reduce with the acceleration of the slider produced by dynamic friction force, the rigid kinematics model is also verified by simulation results which are explained in further detail in the article.

Study on the Relationship of Airbag Effect and Occupant Position

2011 ◽  
Vol 299-300 ◽  
pp. 1279-1282
Author(s):  
Xiu Chunb Wu ◽  
Kun Li ◽  
Bo Wang ◽  
Xue Shenc Su
Keyword(s):  
Computer Simulation ◽  
Traffic Accident ◽  
Simulation Method ◽  
Simulation Test ◽  
Computer Simulation Method ◽  
Simulation Results ◽  
Relationship Of ◽  
The Relationship

Computer simulation method is used to study the relations of airbag effect and occupant position. By changing the position of 50% dummy model to achieve the purpose of changing the position between airbag and occupant, three kinds of simulation test are made, and the simulation results are analyzed and compared. It is shown that between the belted occupant and airbag exists such a position or distance, at which the injury to occupant is the smallest when the traffic accident happens.

Open innovation practices adopted by private stakeholders: perspectives for living labs

Info ◽  
2015 ◽  
Vol 17 (4) ◽  
pp. 67-80 ◽  
Author(s):  
Dominic Lapointe ◽  
David Guimont
Keyword(s):  
Open Innovation ◽  
Research Literature ◽  
Extensive Literature ◽  
Content Type ◽  
Living Lab ◽  
Living Labs ◽  
Innovation Practices ◽  
Relationship Of ◽  
The Relationship

Purpose – This paper aims to explore the role of private stakeholders in the living lab (LL) ecosystem and the relationship of private stakeholders to open innovation (OI) practices. There is extensive literature on private stakeholders and OI, but seldom mention is made on the specific question of how private stakeholders integrate OI in the context of a LL. Design/methodology/approach – The authors will analyze qualitatively how private businesses that have participated in a in situ open innovation evaluate and perceived their open innovation practices. Therefore, how they relate to open innovation. Then, the authors will identify a typology of the businesses in relation to OI. Findings – The research focused on the relationship of private stakeholders to OI in the context of in situ OI activities. The results obtained are consistent with literature on OI (Chesbrough, 2003). However, there are differences: if the elements mentioned by the respondents are described in literature, their representation of OI and its components allows us to affirm that this practice is not generalised and that it is often open to interpretation. That emphasises the importance of the role LLs can play as intermediaries to accompany private stakeholders in the OI process. Private stakeholders look for a guide to develop their OI know-how and find their way in the OI ecosystem. Originality/value – The value of this paper is to bridge the research on OI done with private organisation and the research on LLs. The research literature did not pay much attention to the representation of the private stakeholders in the OI ecosystem. This paper has provided the start to open up that field.

Research on the Relationship of Flow Velocity and Particles’ Separation in Cyclone

2012 ◽  
Vol 479-481 ◽  
pp. 2529-2532
Author(s):  
Ying Zhang ◽  
Zhen Wei Zhang
Keyword(s):  
Numerical Simulation ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Structure Design ◽  
Rotating Flow ◽  
Separation Performance ◽  
Simulation Results ◽  
Relationship Of ◽  
The Relationship ◽  
Distribution Of Flow

This paper mainly focuses on the numerical simulation of flow velocity aiming to obtain the velocity distribution of flow in the cyclone. The authors took advantage of RSM turbulence model of software FLUENT to calculate the velocity distribution. Relationship between particles separation and double-layer rotating flow can be obtained based on the simulation results, which can also provide basis for the improvement of structure design and separation performance.

Highway Alignment Parameters Design and Capacity Analysis on Two-Lane Highway

2014 ◽  
Vol 539 ◽  
pp. 860-866
Author(s):  
Jiang Liu
Keyword(s):  
Capacity Analysis ◽  
Horizontal Curve ◽  
Mountainous Areas ◽  
Key Factors ◽  
Horizontal Curves ◽  
Percent Time ◽  
Simulation Results ◽  
Relationship Of ◽  
Highway Alignment ◽  
The Relationship

A two-lane highway is an undivided highway with only one lane of traffic in each direction. Two-lane highways are one of the most common roadways at mountainous areas in China. Due to the wider range to choose the horizontal and vertical curves in the design of two-lane highways, the combination of both leads to larger differences on two-lane highway capacities. Thus, the highway alignments are one of the key factors which affect the two-lane highway capacities. According to the empirical data and existing studies, it is regarded that there is no impacts on the capacity for horizontal curves with a radius more than 400m and vertical curves with the gradient less than 3%. Two concepts are defined as effective bending and effective gradient which represent the extent the horizontal curve bends and the steepness of vertical curve respectively. The method to calculate effective bending of horizontal curve and steepness of vertical curve is given and its relevant properties are also discussed. According to the simulation results and the principle of speed differences, the effective bending and effective gradient have been classified into 7 and 6 levels, separately. As a result, there will be 42 combinations of different highway alignments of two-lane highways based on the different combinations of the effective bending and effective gradient. Under this circumstance, the relationship of speed-volume and volume-PTSF (percent time spend following) are obtained from the simulation results. Finally, the capacity of two-lane highway is given under different highway alignments of two-lane highway at mountainous areas in China.

scholarly journals Mixed-Valence Cytoplasmic Iron Granules Are Linked to Anaerobic Respiration

2006 ◽  
Vol 73 (3) ◽  
pp. 993-996 ◽  
Author(s):  
S. Glasauer ◽  
S. Langley ◽  
M. Boyanov ◽  
B. Lai ◽  
K. Kemner ◽  
...  
Keyword(s):  
Ferrous Iron ◽  
Metal Particle ◽  
Ferric Iron ◽  
Solid Phase ◽  
Mixed Valence ◽  
Anaerobic Respiration ◽  
In Situ Detection ◽  
Relationship Of ◽  
The Relationship

ABSTRACT Intracellular granules containing ferric and ferrous iron formed in Shewanella putrefaciens CN32 during dissimilatory reduction of solid-phase ferric iron. It is the first in situ detection at high resolution (150 nm) of a mixed-valence metal particle residing within a prokaryotic cell. The relationship of the internal particles to Fe(III) reduction may indicate a respiratory role.

scholarly journals EFFECT OF BLASTING ON THE STABILITY OF LINING DURING EXCAVATION OF NEW TUNNEL NEAR THE EXISTING TUNNEL

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Quang Huy Nguyen
Keyword(s):  
Field Data ◽  
Damage Zone ◽  
Field Tests ◽  
Surrounding Rock ◽  
In Situ Test ◽  
The Stability ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working.

scholarly journals Abundant expression of transcription factor GATA-2 in proliferating but not in differentiated mast cells in tissues of mice: demonstration by in situ hybridization

Blood ◽  
1996 ◽  
Vol 87 (3) ◽  
pp. 993-998 ◽  
Author(s):  
T Jippo ◽  
H Mizuno ◽  
Z Xu ◽  
S Nomura ◽  
M Yamamoto ◽  
...  
Keyword(s):  
Mast Cell ◽  
In Situ Hybridization ◽  
Mast Cells ◽  
Differentiation Markers ◽  
Two Parameters ◽  
High Affinity Ige Receptor ◽  
Relationship Of ◽  
The Relationship ◽  
Receptor Beta

Although GATA-binding transcription factors (GATA-1 and GATA-2) are strongly expressed in cultured mast cells (CMCs), their expression in mast cells within tissues has not been reported. We examined the expression of GATA-1 and GATA-2 in skin tissues of mice using Northern blot analysis and in situ hybridization. mRNA for GATA-2 but not for GATA-1 was expressed in skin mast cells of WB-+/+ embryos between days 15 and 17 postcoitum (pc). The expression was downregulated on and after day 18 pc. Skin mast cells did not express GATA-2 after birth either. When the number of skin mast cells was compared with the number of GATA-2 mRNA-expressing cells, GATA-2 mRNA appeared to be expressed by mast cells only when the number was increasing. When the mRNA expression of high-affinity IgE receptor beta-subunit and mast cell carboxypeptidase A was used as differentiation markers, the expression of these mRNAs continued even after the downregulation of GATA-2 expression. To clarify the relationship of the proliferation and GATA-2 expression, proliferating CMCs derived from WBB6F1-+/+ mice were transplanted into the peritoneal cavity of mast cell-deficient WBB6F1- W/Wv mice. The CMCs stopped both the proliferation and GATA-2 expression after the transplantation, suggesting the association of these two parameters in mast cells within tissues of mice.

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