A5051674112- Glass properties and applications
- Silicon Nanostructures and Photoluminescence
- Luminescence Properties of Advanced Materials
- Semiconductor materials and devices
- Material Dynamics and Properties
- Adsorption and Cooling Systems
- X-ray Spectroscopy and Fluorescence Analysis
- Microwave-Assisted Synthesis and Applications
- Surfactants and Colloidal Systems
- Ion-surface interactions and analysis
- Metal and Thin Film Mechanics
- Spectroscopy and Quantum Chemical Studies
- X-ray Diffraction in Crystallography
- Microwave and Dielectric Measurement Techniques
- Microstructure and mechanical properties
- Ammonia Synthesis and Nitrogen Reduction
- Phase Change Materials Research
- Catalytic Processes in Materials Science
- Aerogels and thermal insulation
- Membrane Separation and Gas Transport
- Photonic and Optical Devices
- Adhesion, Friction, and Surface Interactions
- Thin-Film Transistor Technologies
- Advanced Chemical Physics Studies
- Nanomaterials and Printing Technologies
University of Edinburgh
2018-2025
Egypt Nanotechnology Center
2011-2016
University of Kent
2009-2016
IBM Research - Zurich
2011
University of Trento
2006-2009
Assiut University
2008
Climate change and the continual rise in cooling demand means more efficient environmentally friendly refrigeration technologies are required than ever. One attractive route to reducing future is improve adsorption based on natural refrigerants such as ammonia. The choice of ammonia adsorbent plays an important role achieving improved efficiency suitable operating conditions. This paper reports a detailed study suitability zeolites applications. Systematic Monte Carlo simulations were...
Climate change and the continual rise in cooling demand means more efficient environmentally friendly refrigeration technologies are required than ever. One attractive route to reducing future is improve adsorption based on natural refrigerants such as ammonia. The choice of ammonia adsorbent plays an important role achieving improved efficiency suitable operating conditions. This paper reports a detailed study pore size thermal efficiency, desorption temperature capacity ammonia–carbon...
This paper reports a molecular-dynamics study on the clustering of ${\text{Eu}}^{3+}$ ions incorporated in ${\text{SiO}}_{2}$ glass. Classical experiments were carried out $x{\text{Eu}}_{2}{\text{O}}_{3}\text{\ensuremath{-}}(100\ensuremath{-}x){\text{SiO}}_{2}$ ($x=0$, 1, 2, 3, 4, and $5\text{ }\text{mol}\text{ }%$) glasses using empirical pairwise Morse interatomic potentials. Due to statistically improved simulation results, averaged over hundreds ions, effects...
Extended x-ray absorption fine structure has been measured on two powdered samples of (70)Ge and (76)Ge as a function temperature from 20 to 300 K. The effect isotopic mass difference the amplitude relative atomic vibrations is neatly evidenced by dependence Debye-Waller factors. also detected nearest-neighbor average ineratomic distances, thanks resolution better than 10 fm.
This paper describes the structure of Er3+-doped SiO2–HfO2 waveguides containing nanocrystals HfO2. Pure and 1 mol% 70SiO2–30HfO2 films were deposited by sol–gel method on amorphous SiO2 substrates using dip-coating technique. Each waveguide has experienced a single thermal treatment at temperatures ranging from 900 to 1200 °C, for either short (30 min) or long (24 h) durations. Crystallization microstructure studied x-ray diffraction (XRD). The local environments hafnium erbium ions...
Large-scale classical and quantum simulations are used to generate a-Si:H structures. The bond-resolved density of the occupied electron states discloses nature microscopic defects responsible for levels in gap. Highly strained bonds give rise band tails midgap states. latter originate mainly from stretched bonds, addition dangling can act as hole traps. This study provides strong evidence photoinduced degradation (Staebler-Wronski effect) driven by strain, thus supporting recent work on...
Slippery liquid-infused porous surfaces (SLIPS) are an innovation that reduces droplet-solid contact line pinning and interfacial friction. Recently, it has been shown a liquid analogue of Young's law can be deduced for the apparent angle sessile droplet on SLIPS despite there never being by with underlying solid. Since angles solids used to characterize solid-liquid interactions wetting solid liquid, is our hypothesis liquid-liquid surface characterized SLIPS. Here, we first present theory...
Rare-earth-doped glasses are key materials for optical technology due to the luminescent properties of $4{f}^{n}$ ions. The crystal-field model describes effect local environment on transitions between $4f$ electrons. We present a detailed modeling study spectra sodium disilicate glass, $33{\mathrm{Na}}_{2}\mathrm{O}\ifmmode\cdot\else\textperiodcentered\fi{}67{\mathrm{SiO}}_{2}$, doped with $0.2%$ and 1.0 mol% ${\mathrm{Eu}}_{2}{\mathrm{O}}_{3}$. This uses very large molecular dynamics...
We perform a complete classical molecular dynamics study of the dielectric heating water in microwave (MW) region. MW frequencies ranging from 1.0 to 15.0 GHz are used together with series well-known empirical force fields. show that ability an field correctly predict response liquids radiation should be evaluated on basis joint comparison predicted and experimental static constant, frequency-dependent spectra, profiles. argue this is essential when multicomponent studied. find both...
A major limitation of amine-based post-combustion carbon capture technology is the necessity to regenerate amines at high temperatures, which dramatically increases operating costs. This paper concludes effect solvent choice as a possible route modify thermodynamics and kinetics characterizing involved amine regeneration reactions discusses whether these modifications can be economically beneficial. We report experimentally benchmarked computational chemistry calculations monoethanolamine...
${\mathrm{Er}}^{3+}$-doped $\mathrm{Si}{\mathrm{O}}_{2}\text{\ensuremath{-}}\mathrm{Hf}{\mathrm{O}}_{2}$ glassy waveguides with $\mathrm{Hf}{\mathrm{O}}_{2}$ concentrations ranging from $10\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}50\phantom{\rule{0.3em}{0ex}}\mathrm{mol}\phantom{\rule{0.2em}{0ex}}%$ were prepared using the sol-gel route and deposited on $v\text{\ensuremath{-}}\mathrm{Si}{\mathrm{O}}_{2}$ substrates dip-coating technique. The local environment around...
The equilibrium cluster fluid state of a symmetric binary mixture particles interacting through short-ranged attractive and long-ranged repulsive interactions is investigated Monte Carlo simulations. We find that the clustering behavior this system controlled by cross-interaction between two types particles. For weak cross-attraction, displays composite individual components, i.e., components can both form giant clusters independently distribute evenly in system. strong we instead resulting...
Recent experiments with undersaturated aqueous glycine solutions have repeatedly exhibited the presence of giant liquid-like clusters or nanodroplets around 100 nm in diameter. These re-appear even after careful efforts for their removal and purification solution. The composition these is not clear, although it has been suggested that they are mainly composed glycine, a small very soluble amino acid. To gain insights into this phenomenon, we study aggregation at concentrations below...
Silica-hafnia glass-ceramics waveguides activated by Er<sup>3+</sup> ions were fabricated sol-gel route. X ray diffraction and optical spectroscopy showed that after an adapted heat treatment, the resulting materials a crystalline environment. Analysis of luminescence properties has demonstrated erbium are, at least partially, trapped in phase. Losses measurements different wavelength highlight very low attenuation coefficient indicating this nanostructured material is suitable for single...
We present a complete classical molecular dynamics (MD) study of the dielectric heating liquid monoethanolamine (MEA) at microwave (MW) frequencies ranging from 1.0 to 10.0 GHz. The detailed properties predicted by series existing empirical force fields MEA were carefully compared experimental results. find that all evaluated unable accurately predict static constant, frequency-dependent spectra, and MW profiles MEA, although GROMOS-aa (all-atom GROningen simulation) is most accurate those...
The analysis of the EXAFS signals from 70Ge and 76Ge has evidenced low-temperature effect isotopic mass difference on amplitude relative atomic vibrations. This is reflected in Debye-Waller factors first three coordination shells, nearest-neighbour average interatomic distances, evaluated with femtometer accuracy. experimental results are agreement theoretical expectations.
The importance of the formation giant clusters in solution, nature and industry, is increasingly recognized. However, relatively little attention has been paid to solutions small, soluble but nonamphiphilic molecules. In this work, we present a general methodology based on molecular dynamics that can be used investigate such systems. As case study, focus apparently stable pentaethylenehexamine (PEHA) water. These have as templates for construction bioinspired silica nanoparticles. To better...
We use Monte Carlo simulations to investigate the effect of incorporating calcium chloride salt into nanoporous carbon on performance an ammonia–carbon adsorption refrigeration system. Simulations ideal slit-pores with pore sizes 1, 2, and 3 nm, each containing ion densities 0.0, 0.25, 0.5 nm−3, were carried out at temperatures between 0 30 °C ammonia pressures up 15.0 bar. The results reveal that 1 nm pores are able achieve a good using waste heat below 100 drive process, but adding these...
A recent CO2 capture experiment suggests that microwaves might be beneficial for regeneration of aqueous amine solutions due to both thermal and nonthermal effects [S. J. McGurk et al., Appl. Energy 192, 126 (2017)]. We use classical molecular dynamics simulate heating using electromagnetic radiation with different frequencies in microwave infrared regions. The were selected based on the partial vibrational density states water amine. Unlike case, we found preferential or can achieved their...