Thermally activated transitions in a bistable three-dimensional optical trap

Nature ◽  
10.1038/45492 ◽  
1999 ◽  
Vol 402 (6763) ◽  
pp. 785-787 ◽  
Author(s):  
Lowell I. McCann ◽  
Mark Dykman ◽  
Brage Golding
Keyword(s):  
Optical Trap ◽  
Three Dimensional ◽  
Thermally Activated

Investigation on On-Board High-Pressure Composite Tanks Subjected to Localized and Engulfing Fire

2012 ◽  
Author(s):  
Kesheng Ou ◽  
Jinyang Zheng ◽  
Yongzhi Zhao
Keyword(s):  
High Pressure ◽  
Exposure Time ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Fire Exposure ◽  
Key Factors ◽  
Activation Time ◽  
Thermally Activated ◽  
Tank Pressure ◽  
Composite Tank

Safety performance of on-board high-pressure composite tanks under fire exposure has drawn extensive attention. Vehicle fires usually lead to such tanks experiencing a term of localized and engulfing fire. During this period, the composite tank would be degraded and even burst before pressure relief device (PRD) opens to release internal high-pressure gas. In this paper, experimental investigation for the tanks subjected to localized and engulfing fire was conducted on an Aluminum liner composite tank filled with hydrogen. Based on the temperature distribution and pressure rise measured in the experiment, a three-dimensional computational fluid dynamics model is developed to study the key factors influencing PRD activation time. The effects of filling medium, tank pressure and localized fire exposure time are analyzed in detail. The experimental results showed that pressure and temperature of internal gas changed little during the localized fire. In addition, filling medium and tank pressure have weak influence on the activation time of thermally-activated PRD (TPRD), but have significant effect on the activation time of pressure-activated PRD. TPRD can respond more quickly to protect the hydrogen composite tank than pressure-activated PRD. PRD activation time increases as the localized fire exposure time extends.

The mechanical properties of kinesin-1: a holistic approach

2012 ◽  
Vol 40 (2) ◽  
pp. 438-443 ◽  
Author(s):  
George M. Jeppesen ◽  
J.K. Heinrich Hoerber
Keyword(s):  
Mechanical Properties ◽  
Atp Hydrolysis ◽  
Optical Trap ◽  
Three Dimensional ◽  
In Vitro Study ◽  
Holistic Approach ◽  
Weakly Coupled ◽  
Kinesin Molecule ◽  
Mechanochemical Cycle

During the last 25 years, a vast amount of research has gone into understanding the mechanochemical cycle of kinesin-1 and similar processive motor proteins. An experimental method that has been widely used to this effect is the in vitro study of kinesin-1 molecules moving along microtubules while pulling a bead, the position of which is monitored optically while trapped in a laser focus. Analysing results from such experiments, in which thermally excited water molecules are violently buffeting the system components, can be quite difficult. At low loads, the effect of the mechanical properties of the entire molecule must be taken into account, as stalk compliance means the bead position recorded is only weakly coupled to the movement of the motor domains, the sites of ATP hydrolysis and microtubule binding. In the present review, findings on the mechanical and functional properties of the various domains of full-length kinesin-1 molecules are summarized and a computer model is presented that uses this information to simulate the motion of a bead carried by a kinesin molecule along a microtubule, with and without a weak optical trap present. A video sequence made from individual steps of the simulation gives a three-dimensional visual insight into these types of experiment at the molecular level.

Mobility of Self-Interstitial Clusters in FE and CU

1998 ◽  
Vol 527 ◽  
Author(s):  
Yu.N. Osetsky ◽  
A. Serra ◽  
V. Priego
Keyword(s):  
Cluster Size ◽  
Md Simulation ◽  
Three Dimensional ◽  
Migration Energy ◽  
Jump Frequency ◽  
Extensive Simulation ◽  
One Dimensional ◽  
Thermally Activated ◽  
Pair Potentials ◽  
Bias Model

ABSTRACTMolecular dynamics (MD) simulation has been used to study the thermally activated mobility of clusters of self-interstitial atoms (SIAs) in Fe and Cu. Such clusters are formed in metals during irradiation with energetical particles and, according to the cascade production bias model, they play an important role in the microstructure evolution of metals under irradiation. An extensive simulation of clusters from 2 to 30 interstitials has been carried out for the temperature range ≍360-1200K using long-range interatomic pair potentials. The results show that clusters bigger than two SIAs are one-dimensionally mobile. Di-interstitials have two migration mechanisms depending on the temperature. At low temperature the mechanism is one-dimensional whereas at high temperature the probability of rotation and three-dimensional migration increases. It was found that in both metals the effective migration energy of clusters estimated via their jump frequency does not depend on the cluster size, although the cluster jump frequency decreases as the cluster size increases. The mechanism of cluster migration and problems of the treatment of one-dimensional mobility are discussed.

The Effect of Surface on the Kinetics of Crystallization of Pd-Si Glassy Metals

1986 ◽  
Vol 80 ◽  
Author(s):  
A. Calka ◽  
A. P. Radliński
Keyword(s):  
Nucleation Rate ◽  
Metallic Glasses ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Growth Morphology ◽  
Thermally Activated ◽  
Glassy Metals ◽  
Dimensional Growth ◽  
Kinetics Of ◽  
Effect Of Surface

IntroductionThe isothermal devitrification by nucleation and growth of metallic glasses is usually analysed using the Johnson-Mehl-Avrami (JMA) equation: where x is the volume fraction crystallized after time t, K is a thermally activated rate constant, τ is the nucleation lag time, and n is the so-called Avrami exponent. If the nucleation conditions and growth morphology remain unchanged during the crystallization then n is a constant. There is ample experimental evidence that for the Pd-Si system the growth process is either eutectic or interface-controlled. Therefore, one expects n=3 for crystallization on pre-existing nuclei (zero nucleation rate) and n=4 for crystallization at constant nucleation rate, both for three-dimensional growth. When the growth dimensionality is decreased by one these values decrease stepwise by one as well.

scholarly journals Three-dimensional mesoporous calcium carbonate–silica frameworks thermally activated from porous fossil bryophyte: adsorption studies for heavy metal uptake

RSC Advances ◽  
2018 ◽  
Vol 8 (45) ◽  
pp. 25754-25766 ◽  
Author(s):  
Wenlei Wang ◽  
Ren He ◽  
Tianli Yang ◽  
Yunchu Hu ◽  
Ning Zhang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Calcium Carbonate ◽  
Metal Uptake ◽  
Three Dimensional ◽  
Heavy Metal Uptake ◽  
Adsorption Studies ◽  
Thermally Activated ◽  
Adsorption Capacities

Three-dimensional mesoporous calcium carbonate–silica frameworks have been created and have shown excellent adsorption capacities for Cd(ii) and Pb(ii).

Three-dimensional analysis of the magneto-optical trap for (1+3)-level atoms

2008 ◽  
Vol 77 (1) ◽  
Author(s):  
Sang-Kyung Choi ◽  
Sang Eon Park ◽  
Jingbiao Chen ◽  
Vladimir G. Minogin
Keyword(s):  
Dimensional Analysis ◽  
Optical Trap ◽  
Three Dimensional ◽  
Magneto Optical Trap
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