Results 91 to 100 of about 515,451 (307)

A New Spin Foam Model for 4d Gravity

, 2008
Starting from Plebanski formulation of gravity as a constrained BF theory we propose a new spin foam model for 4d Riemannian quantum gravity that generalises the well-known Barrett-Crane model and resolves the inherent to it ultra-locality problem.
Alexandrov S, Ashtekar A, Baez J C, Baez J C, Baratin A, Barrett J W, Barrett J W, Buffenoir E, Capovilla R, De Pietri R, Engle J Livine E Pereira R Rovelli C, Engle J Pereira R Rovelli C, Freidel L, Freidel L, Freidel L, Gelfand I M, Kirill Krasnov, Laurent Freidel, Livine E R Speziale S, Perelomov A, Ponzano G, Reisenberger M P, Reisenberger M P   +22 more
core   +1 more source

Spin Foams [PDF]

, 2014
The spin foam framework provides a way to define the dynamics of canonical loop quantum gravity in a spacetime covariant way, by using a path integral over histories of quantum states which can be interpreted as `quantum space-times'. This chapter provides a basic introduction to spin foams aimed principally at beginning graduate students and, where ...
openaire   +2 more sources

Electroactive Metal–Organic Frameworks for Electrocatalysis

Advanced Functional Materials, EarlyView.
Electrocatalysis is crucial in sustainable energy conversion as it enables efficient chemical transformations. The review discusses how metal–organic frameworks can revolutionize this field by offering tailorable structures and active site tunability, enabling efficient and selective electrocatalytic processes.
Irena Senkovska, Yutong Luo, Ruyan Zhao, Jianjun Zhang, Mingchao Wang, Xinliang Feng, Eike Brunner, Stefan Kaskel   +7 more
wiley   +1 more source

Auto‐Generated Valence States in Electrocatalysts for Boosting Oxygen and Hydrogen Evolution Kinetics in Alkaline Water/Alkaline Seawater/Simulated Seawater/Natural Seawater

Advanced Functional Materials, EarlyView.
This review systematically highlights the latest achievements in mixed‐valence states relevant to hydrogen and oxygen evolution reactions, providing essential insights into future directions and methods for large‐scale practical implementation. This critical review is expected to provide an overview of recent advancements in diverse valence‐state metal
Jitendra N. Tiwari, Gokul Bhaskaran, Krishan Kumar, Yun Suk Huh, Young‐Kyu Han   +4 more
wiley   +1 more source

Generation of Biocompatible Pcl Foams by Supercritical Foaming

Chemical Engineering Transactions, 2020
In this work, polycaprolactone (PCL) foams were generated by a supercritical CO2 (SC-CO2) assisted process. These foams can find application in tissue engineering as scaffolds, which require specific biological and morphological properties. SC-CO2 foaming process was carried out under different pressure and temperature conditions, in order to study the
Baldino L., Cardea S.
openaire   +3 more sources

Through Diamond Robust Surface Enhanced Raman Spectroscopy

Advanced Functional Materials, EarlyView.
Thin film diamond growth offers a unique opportunity for Surface Enhanced Raman Spectroscopy (SERS); the encapsulation of plasmonic nanostructures within a transparent, chemically stable, and physically robust coating. The diamond acts as both a window and protective layer, enabling illumination of the plasmonic nanostructures through the diamond ...
Kieran N. Twaddle, Rebecca J. Watkins, Ralph J. Moors, Massimiliano L.A. Ramsay, Richard B. Jackman   +4 more
wiley   +1 more source

New Biocide Foam Containing Hydrogen Peroxide for the Decontamination of Vertical Surface Contaminated With Bacillus thuringiensis Spores

Frontiers in Microbiology, 2018
Despite scientific advances, bacterial spores remain a major preoccupation in many different fields, such as the hospital, food, and CBRN-E Defense sector.
Esther Le Toquin, Esther Le Toquin, Sylvain Faure, Nicole Orange, Fabienne Gas   +4 more
doaj   +1 more source

Fire retardant polyisocyanurate foam [PDF]

, 1972
Fire retardant properties of low density polymer foam are increased. Foam has pendant nitrile groups which form thermally-stable heterocyclic structures at temperature below degradation temperature of urethane ...
Parker, J. A., Riccitiello, S. R.
core   +1 more source

Additive Manufacturing of NiTi Shape Memory Alloys for Elastocaloric Applications: A Review

Advanced Functional Materials, EarlyView.
Additive manufacturing enables complex NiTi architectures that overcome key limitations in elastocaloric refrigeration, including poor heat transfer and high mechanical work input. This review surveys recent advances in LPBF‐ and DED‐fabricated NiTi shape memory alloys for elastocaloric applications, highlighting process–structure–performance ...
Ignatius Andre Setiawan, Mohammad Mehrali, Jaka Tušek, Shiva Mohajerani, Xiebin Wang, Dermot Brabazon, Mohammad Elahinia, Mehrshad Mehrpouya   +7 more
wiley   +1 more source

Shock Wave Attenuation Using Foam Obstacles: Does Geometry Matter?

Aerospace, 2015
A shock wave impact study on open and closed cell foam obstacles was completed to assess attenuation effects with respect to different front face geometries of the foam obstacles.
Hongjoo Jeon, Jonathan R. Gross, Sarah Estabrook, Stylianos Koumlis, Qian Wan, Gauri R. Khanolkar, Xingtian Tao, David M. Mensching, Edward J. Lesnick, Veronica Eliasson   +9 more
doaj   +1 more source