Hydrogen energy storage in porous media

The demand for sustainable and clean energy sources has become increasingly vital in addressing the challenges of climate change and energy security. Hydrogen, with its high energy density and potential for carbon-free energy conversion, has emerged as a promising candidate for future energy systems. Efficient storage and retrieval of hydrogen...

Automated and high-throughput reactivity analysis in homogeneous catalysis: The deactivation complexity of Mn(I) hydrogenation catalysts

In this thesis, I highlighted a number of projects aimed at developing and testing new simulation methods for studying complex reactive systems, with a particular emphasis on simulation strategies based on the concept of bonding graphs. These mathematical structures provide useful tools for a variety of algorithms developed over the last few...

Automated actual evapotranspiration estimation: Hybrid model of a novel attention based U-Net and metaheuristic optimization algorithms

Actual evapotranspiration (ET_a) plays a crucial role in the water and energy cycles of the earth. An accurate estimate of the ET_a is essential for management of the water resources, agriculture, and irrigation, as well as research on atmospheric variations. Despite the importance of accurate ET_a values,...

HiREX: High-Throughput Reactivity Exploration for Extended Databases of Transition-Metal Catalysts

A method is introduced for the automated analysis of reactivity exploration for extended in silico databases of transition-metal catalysts. The proposed workflow is designed to tackle two key challenges for bias-free mechanistic explorations on large databases of catalysts: (1) automated exploration of the chemical space around each catalyst...

Physics-based modelling and data-driven optimisation of a latent heat thermal energy storage system with corrugated fins

Solid-liquid phase transformation of a phase change material in a rectangular enclosure with corrugated fins is studied. Employing a physics-based model, the influence of fin length, thickness, and wave amplitude on the thermal and fluid flow fields is explored. Incorporating fins into thermal energy storage systems enhances the heat transfer...

A comparative study for H₂–CH₄ mixture wettability in sandstone porous rocks relevant to underground hydrogen storage

Characterizing the wettability of hydrogen (H₂)–methane (CH₄) mixtures in subsurface reservoirs is the first step towards understanding containment and transport properties for underground hydrogen storage (UHS). In this study, we investigate the static contact angles of H₂–CH₄ mixtures, in contact...

Microfluidics-based analysis of dynamic contact angles relevant for underground hydrogen storage

Underground Hydrogen Storage (UHS) is an attractive technology for large-scale (TWh) renewable energy storage. To ensure the safety and efficiency of the UHS, it is crucial to quantify the H₂ interactions with the reservoir fluids and rocks across scales, including the micro scale. This paper reports the experimental measurements...

High-Power Digital Transmitters for Wireless Infrastructure Applications (A Feasibility Study)

Fully digital transmitters (DTXs) have the potential of replacing analog-intensive transmitter (TX) line-ups in future massive multiple-input and multiple-output (mMIMO) systems since they hold the promise of higher system integration level and energy efficiency. DTX operation so far has been limited to low RF output powers. This article...

ReNeGate: A Reaction Network Graph-Theoretical Tool for Automated Mechanistic Studies in Computational Homogeneous Catalysis

Exploration of the chemical reaction space of chemical transformations in multicomponent mixtures is one of the main challenges in contemporary computational chemistry. To remove expert bias from mechanistic studies and to discover new chemistries, an automated graph-theoretical methodology is proposed, which puts forward a network formalism...

Pore-scale modelling and sensitivity analyses of hydrogen-brine multiphase flow in geological porous media

Underground hydrogen storage (UHS) in initially brine-saturated deep porous rocks is a promising large-scale energy storage technology, due to hydrogen's high specific energy capacity and the high volumetric capacity of aquifers. Appropriate selection of a feasible and safe storage site vitally depends on understanding hydrogen transport...

Contact angle measurement for hydrogen/brine/sandstone system using captive-bubble method relevant for underground hydrogen storage

Subsurface porous formations provide large capacities for underground hydrogen storage (UHS). Successful utilization of these porous reservoirs for UHS depends on accurate quantification of the hydrogen transport characteristics at continuum (macro) scale, specially in contact with other reservoir fluids. Relative-permeability and capillary...

Energy Efficient and Intrinsically Linear Digital Polar Transmitters

One of the biggest challenges in modern transmitter (TX) design, when going from the fourth generation (4G) to fifth generation (5G) communications network, is to handle the increased linearity requirements without introducing any compromise in the energy efficiency of the TX line-up. In analog systems, high quality for the TX signal can be only...

Atomic Layer Deposition of ZnO on InP Quantum Dot Films for Charge Separation, Stabilization, and Solar Cell Formation

To improve the stability and carrier mobility of quantum dot (QD) optoelectronic devices, encapsulation or pore infilling processes are advantageous. Atomic layer deposition (ALD) is an ideal technique to infill and overcoat QD films, as it provides excellent control over film growth at the sub-nanometer scale and results in conformal...

A Highly Linear Wideband Polar Class-E CMOS Digital Doherty Power Amplifier

This article presents the first application of a digital-intensive intrinsically linear digitally controlled class-E technique in a Doherty configuration. By careful nonlinear segmentation and multiphase RF-clocking along with overdrive-voltage control and automatic duty-cycle correction, it is shown that even the nonlinearities related to...

Computational Approach to Molecular Catalysis by 3d Transition Metals: Challenges and Opportunities

Computational chemistry provides a versatile toolbox for studying mechanistic details of catalytic reactions and holds promise to deliver practical strategies to enable the rational in silico catalyst design. The versatile reactivity and nontrivial electronic structure effects, common for systems based on 3d transition metals, introduce...

Gas chimney detection based on improving the performance of combined multilayer perceptron and support vector classifier

Seismic object detection is a relatively new field in which 3-D bodies are visualized and spatial relationships between objects of different origins are studied in order to extract geologic information. In this paper, we propose a method for finding an optimal classifier with the help of a statistical feature ranking technique and combining...

Phase modeling of indoor radio propagation channels