scholarly journals Design of impact reduction mechanism using momentum exchange and avoidance of impact transmission by mechanical singularity inspired by Break-Fall in Judo

Author(s):  
Masafumi OKADA ◽  
Hiroaki KUROSU
2019 ◽  
Author(s):  
Christian Prehal ◽  
Aleksej Samojlov ◽  
Manfred Nachtnebel ◽  
Manfred Kriechbaum ◽  
Heinz Amenitsch ◽  
...  

<b>Here we use in situ small and wide angle X-ray scattering to elucidate unexpected mechanistic insights of the O2 reduction mechanism in Li-O2 batteries.<br></b>


Impact ◽  
2019 ◽  
Vol 2019 (10) ◽  
pp. 73-75
Author(s):  
Susumu Hara

Professor Susumu Hara is based at the Department of Aerospace Engineering, Nagoya University in Japan explains that when the Mars rover Opportunity was set to land on that planet in the first weeks of 2004, onlookers held their breath as it dropped from orbit and hurtled toward the red surface. 'Any failure in the calculations or landing systems would mean a harder than expected impact,' he highlights. 'The impacts sustained by a rover such as Opportunity can derail a mission before it even starts, damaging cargo or vital systems required to complete the mission.' Impacts occur during landing but also as the craft enters the atmosphere, when it makes sudden moves, while it is on surface or when debris strikes it. 'Therefore, a system and materials to protect a craft are vital,' outlines Hara. 'Surprisingly, the solutions to this problem are not sophisticated. In fact, most craft still employ devices resembling automobile bumpers, which absorb the energy from an impact by crumpling under the force of said impact.' Unfortunately, these cannot be reused, even during testing phases a new prototype is required after every single test run. Recent missions also employed techniques like airbags or sky cranes. While successful they too have drawbacks. 'Airbags create huge rebounds which can jostle the craft and the contents inside while sky cranes are extremely costly to develop,' Hara says. For this reason, he is dedicated to designing a new highly reliable and cost-effective shock control mechanism.


Author(s):  
Hiroki OKACHI ◽  
Tomohito J. YAMADA ◽  
Yasunori WATANABE
Keyword(s):  

1985 ◽  
Vol 50 (3) ◽  
pp. 712-725 ◽  
Author(s):  
Jiří Barek ◽  
Lubomír Kelnar

The polarographic reduction of N,N-dimethyl-4-amino-4'-hydroxyazobenzene in water-methanol medium was investigated. Evidence is presented for adsorption of the depolarizer on the electrode, and a reduction mechanism is proposed. Conditions are indicated for the determination of this compound in the concentration range 10-4-10-6 mol/l by d.c. polarography, 10-5 to 3 . 10-7 mol/l by Tast polarography, and 10-5-3 . 10-8 mol/l by differential pulse polarography.


1989 ◽  
Vol 54 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Roland Meier ◽  
Harald Frank ◽  
Reinhard Kirmse ◽  
Reiner Salzer ◽  
Joachim Stach ◽  
...  

The voltammetric behaviour of amavadine (AV) was found to be considerably different from that of the complexes of VO2+ with methyliminodiacetic acid (MIDA) and iminodiacetic acid (IDA). To get an insight in the rather complicated reduction mechanism of the latter complexes the reductions of V(III) (MIDA) and V(III) (IDA) have been studied for comparison. The species V(III) (MIDA)2 and V(III) (IDA)2 are reduced to the appropriate V(II) complexes in a chemically reversible process. VO(MIDA)2 and VO(IDA)2 are reduced to the same complexes via an ECE mechanism. The investigation of the electroreduction of AV shows that this process is not reversible in the chemical sense. As a probable explanation, the conclusion was drawn that AV and the usual V(IV)O-iminocarboxylato complexes differ in their structures.


2021 ◽  
Vol 542 ◽  
pp. 148666
Author(s):  
Qianjin Huang ◽  
Zhongqiang Zhang ◽  
Zhen Liu ◽  
Fujian Zhang ◽  
Guanggui Cheng ◽  
...  

2020 ◽  
Vol 499 (3) ◽  
pp. 3690-3705
Author(s):  
M Antonelli ◽  
B Haskell

ABSTRACT Understanding the average motion of a multitude of superfluid vortices in the interior of a neutron star is a key ingredient for most theories of pulsar glitches. In this paper, we propose a kinetic approach to compute the mutual friction force that is responsible for the momentum exchange between the normal and superfluid components in a neutron star, where the mutual friction is extracted from a suitable average over the motion of many vortex lines. As a first step towards a better modelling of the repinning and depinning processes of many vortex lines in a neutron star, we consider here only straight and non-interacting vortices: we adopt a minimal model for the dynamics of an ensemble of point vortices in two dimensions immersed in a non-homogeneous medium that acts as a pinning landscape. Since the degree of disorder in the inner crust or outer core of a neutron star is unknown, we compare the two possible scenarios of periodic and disordered pinscapes. This approach allows us to extract the mutual friction between the superfluid and the normal component in the star when, in addition to the usual Magnus and drag forces acting on vortex lines, also a pinning force is at work. The effect of disorder on the depinning transition is also discussed.


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