Results 71 to 80 of about 238,679 (287)

Null infinity as an open Hamiltonian system

Journal of High Energy Physics, 2021
When a system emits gravitational radiation, the Bondi mass decreases. If the Bondi energy is Hamiltonian, it can thus only be a time-dependent Hamiltonian. In this paper, we show that the Bondi energy can be understood as a time-dependent Hamiltonian on
Wolfgang Wieland
doaj   +1 more source

Quantum fluctuating geometries and the information paradox [PDF]

, 2017
We study Hawking radiation on the quantum space-time of a collapsing null shell. We use the geometric optics approximation as in Hawking's original papers to treat the radiation.
Campiglia, Miguel, Eyheralde, Rodrigo, Gambini, Rodolfo, Pullin, Jorge   +3 more
core   +3 more sources

Effect of Laser Deoxidation on Adhesive‐Bonded Aluminum in an Oxygen‐Free Atmosphere

Advanced Engineering Materials, EarlyView.
This study investigates laser ablation of aluminum under oxygen‐free conditions. The goal is to produce oxide‐free substrates that enable improved adhesive bonding with epoxy. Optimized laser parameters (90% overlap, 300 µJ) combined with oxide‐free substrates result in the highest tensile strength of the adhesive bond.
Sandra Gerland, Finn‐Lennard Janthur, Sarah Seffer, Jörg Hermsdorf, Ludger Overmeyer, Annika Raatz   +5 more
wiley   +1 more source

The causal structure of dynamical charged black holes

, 2010
We study the causal structure of dynamical charged black holes, with a sufficient number of massless fields, using numerical simulations. Neglecting Hawking radiation, the inner horizon is a null Cauchy horizon and a curvature singularity due to mass ...
Ashtekar A, Birrell N D, Dong-han Yeom, Dong-il Hwang, Dunne G V, Ewan D Stewart, Gnedin M L, Hamade R S, Hawking S W, Hayward S A, Hong S E Hwang D Yeom D Zoe H, Hwang D Stewart E D Yeom D, Hwang D Yeom D, Kaminaga Y, Nielsen A B Yeom D, Nordstrom G, Novikov I D, Ori A, Press W H, Strominger A, Sungwook E Hong, Susskind L, Wald R M, Yeom D Zoe H   +23 more
core   +1 more source

Collapsing strange quark matter in Vaidya geometry [PDF]

, 2000
Exact solutions of the gravitational field equations for a mixture of a null charged strange quark fluid and radiation are obtained in a Vaidya space-time.
Bonnor, Cheng, Cheng, Cheng, Cheng, Dai, Dwiwedi, Husain, K.S. Cheng, Lake, Ori, Poisson, Sullivan, T. Harko, Vaidya, Wang, Witten   +16 more
core   +2 more sources

Creating Ti–Fe α/β Alloys by Diffusion‐Driven Solid‐State Processing

Advanced Engineering Materials, EarlyView.
This study proposes making alloys containing fast diffusing elements that are difficult to produce by ingot metallurgy, by diffusion‐driven solid‐state HIP processing of elemental powders and low‐temperature homogenisation. Here, novel Fe‐Ti α–β alloys are formed having fine α–β lamellae, a small β prior grain size without significant intermetallics ...
Jiaqi Xu, Xun Zhang, Jack M. Donoghue, Albert D. Smith, Rahul Unnikrishnan, Rhys Thomas, Vahid Nekouie, Jie Luo, Dongchen Hu, Michael Preuss, Philip J. Withers   +10 more
wiley   +1 more source

Initial data transients in binary black hole evolutions

, 2011
We describe a method for initializing characteristic evolutions of the Einstein equations using a linearized solution corresponding to purely outgoing radiation.
Babiuc M, Babiuc M C Szilagyi B Winicour J Zlochower Y, Bishop N, Bishop N T, Christian Reisswig, Denis Pollney, Gómez R, Lovelace G, Misner C W, Nigel Bishop, Pollney D Reisswig C Schnetter E Dorband N Diener P, Reisswig C, Reisswig C   +12 more
core   +1 more source

Additive Manufacturing of Continuous Fibre Reinforced Composites: Process, Characterisation, Modelling, and Sustainability

Advanced Engineering Materials, EarlyView.
Additive manufacturing provides precise control over the placement of continuous fibres within polymer matrices, enabling customised mechanical performance in composite components. This article explores processing strategies, mechanical testing, and modelling approaches for additive manufactured continuous fibre‐reinforced composites.
Cherian Thomas, Amir Hosein Sakhaei
wiley   +1 more source

Scanning circular array with null constraints onthe radiation pattern

Electronics Letters, 1996
The authors examine the problem of using a circular antenna array to scan a given radiation pattern over an angular sector of the array plane, while satisfying null constraints at prescribed directions of interference. We solve the problem using an algorithm based on the discrete Fourier transform.
openaire   +2 more sources

Copper Nanocrystallization in Anodic Oxide Films of Ti–Cu‐Based Bulk Metallic Glass and Its Effect on the Corrosion Resistance and Cytocompatibility

Advanced Engineering Materials, EarlyView.
Viktoriia Shtefan, Thorgund Nemec, Ute Hempel, Annett Gebert and coworkers demonstrate that anodic treatment of Ti–Cu‐based metallic glass in a nontoxic pyrophosphate electrolyte forms a protective bilayered Ti/Zr‐oxide film enriched with Cu nanocrystals.
Viktoriia Shtefan, Nora Fernández Navas, Thorgund Nemec, Ivan Kaban, Ute Hempel, Andrea Voss, Volker Hoffmann, Darius Pohl, Annett Gebert   +8 more
wiley   +1 more source