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Resistive Sensors: Fundamentals to Applications
Published in Ankur Gupta, Mahesh Kumar, Rajeev Kumar Singh, Shantanu Bhattacharya, Gas Sensors, 2023
Many industries like steel industries, power plants, hydrogen plants deal with gases that are either toxic in nature or are highly inflammable. A recent accident in the Bhilai steel plant, India (2020), injured six people. Similarly, methane emissions are much higher in power plants, which generate electricity from natural gases like in the case of most of the US power plants. Methane is a greenhouse gas that hampers the ozone layer. In a venture to explore alternatives for non-renewable resources of energy, hydrogen is emerging as a promising option. Hydrogen is a highly inflammable gas that creates an explosion if 4% of it comes in contact with air. The Fukushima Daiichi disaster in Japan (2011) is one of the popularly known accidents in which huge explosions occurred due to hydrogen leakage. In order to ensure the safety of workers in workplaces, it is necessary to install leak detection units in abundance. Now, if the number of units to be installed is huge, the cost is one of the primary concerns. In this case, too resistive sensors offer attractive solutions. The portable sensors can be fabricated in a very cost-effective manner, especially opting chemical or hydrothermal routes of synthesis of sensing materials and integration of the sensors with CMOS platforms appear to be enticing.
Sources of Stress and Service Failure Mechanisms
Published in Colin R. Gagg, Forensic Engineering, 2020
There is an insidious mode of brittle failure that will often be encountered in service – that of hydrogen embrittlement. When atomic hydrogen enters a metallic material, it can result in a loss of load-carrying ability, loss of ductility or sub-microscopic cracking. Hydrogen embrittlement is an insidious failure mechanism that can cause unexpected and sometimes catastrophic brittle failure at applied stresses well below the yield strength of the material. Hydrogen embrittlement is therefore considered to be the Achilles’ heel of high-strength ferrous steels and alloys. Hydrogen embrittlement does not affect all metallic materials equally; the most vulnerable are high-strength steels, titanium alloys and aluminium alloys. Although the phenomenon is well-known, extensive research has failed to pinpoint the precise mechanism at play. However, hydrogen embrittlement mechanisms are thought to be diffusion controlled, with current thinking suggesting the susceptibility of any material is directly related to the characteristics of its trap population. In turn, the trap population of any material is related to its microstructure, dislocations, carbides and other elements present in the structure. Therefore, diffusion is controlled by the rate of escape of hydrogen from the traps. It follows that the nature and the density of traps will control the diffusion coefficients.
Thermochemical Conversion of Biomass to Power and Fuels
Published in Jay J. Cheng, Biomass to Renewable Energy Processes, 2017
Hasan Jameel, Deepak R. Keshwani
The production of hydrogen from biomass, via gasification, has a very high level of interest due to its potential use in fuel cells. A fuel cell is an electrochemical device that combines hydrogen and oxygen to produce electricity, with water and heat as its byproduct. Since the conversion of the fuel to energy takes place via an electrochemical process, instead of combustion, the process is clean, quiet, and highly efficient. If efficiency is defined as the ratio of the amount of useful energy to the total energy input, fuel cells have theoretical maximum efficiencies between 80% and 85%. In practice, fuel cell efficiencies are between 35% and 60%. It is expected that the overall tank to wheel efficiency for a car that uses hydrogen based fuel cells will be higher than that for a gasoline or diesel based automobile.
A comprehensive review on techno-environmental analysis of state-of-the-art production and storage of hydrogen energy: challenges and way forward
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Md Rasel Ahmed, Tirtha Barua, Barun K. Das
This concept is founded on the transformation of electricity into hydrogen, application to other industries (like transportation) and aid in their transition to carbon neutrality. The alternative of VRE connection and power transformation to hydrogen by water electrolysis is given particular attention in this study since it enables the efficient use of almost all renewable energy’s surplus that would otherwise be limited. Hydrogen can be used as a building material, in industry (such as the chemical sector), and as a fuel for a variety of vehicles, including land, air, and marine vehicles. It may also be integrated into the grid for natural gas (Widera 2020). Figure 1 shows the P2G flow diagram. The flow diagram represents the overall process of P2G where the HRES for hybrid renewable energy sources.
A Review on Research and Technology Development of Green Hydrogen Energy Systems with Thermal Management and Heat Recovery
Published in Heat Transfer Engineering, 2023
Lixin Cheng, Zhixiong Guo, Guodong Xia
Hydrogen is a clean fuel without toxic emissions and the only by-product is water vapor. It can be applied in fuel cells for electricity generation or combined heat and power systems for heat supply and electricity generation [25,26, 43,44]. The energy yield of hydrogen is 120 − 141.8 kJ/kg depending on temperature, which is about 2.75 times greater than hydrocarbon fuels. Application of hydrogen in transportation system whether as a fuel in combustion engines or fuel cells in electric cars has received much attention in recent years. Vehicles fueled by hydrogen drastically decrease dependence on fossil fuel and conspicuously mitigate tailpipe emissions. The efficiency of hydrogen fuel cell vehicles is three times more than gasoline engines [45]. There are several types of fuel cell technologies mainly categorized based on the membranes used and the mobile ions involved, including PEMFCs, solid oxide, alkaline, direct methanol, phosphoric acid, and molten carbonate fuel cells. Among these different types of fuel cells, PEMFCs have been widely recognized as a promising technology for a range of stationary, transportation, auxiliary, portable, and mobile power supply applications.
Pseudo pair potential between protons in dense hydrogen from first principles
Published in Molecular Physics, 2022
Robbie S. Robinson, Praveer Tiwari, Jeffrey M. McMahon
Hydrogen is the lightest and most abundant element in the universe. Despite its electronic simplicity, its behaviour is surprisingly complex [1], even when compared with other elements. Previous works [2,3], for example, have shown an especially rich [4,5] (albeit yet incomplete) phase diagram of hydrogen as well as many of the outlying thermodynamic conditions governing the quantum behaviour [2,6,7]. In 1935, Wigner and Huntington showed [8] that hydrogen would dissociate into a metallic state with pressure. More recent works [9,10] have suggested the transition to occur more precisely occur around 447 [11–13]–550 GPa [14] at lower temperatures. Significant interest in dense hydrogen continues because of the remarkable expected properties including, for example, superconductivity at high temperatures [15,16], quantum liquid–liquid transition in the ground-state [17] and several other novel types of quantum fluids [18]. Understanding the quantum behaviour of dense hydrogen can lead to technological advancements, including inertial confinement fusion [19], the most powerful, light-weight rocket fuel [20], high-temperature superconductivity [7] (for energy transmission and generation), superfluidity [5], and provide insight on fundamental properties for heavier-element systems [21,22].