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Topic Review
Very-High-Temperature Reactor
The very-high-temperature reactor (VHTR), or high-temperature gas-cooled reactor (HTGR), is a Generation IV reactor concept that uses a graphite-moderated nuclear reactor with a once-through uranium fuel cycle. The VHTR is a type of high-temperature reactor (HTR) that can conceptually have an outlet temperature of 1000 °C. The reactor core can be either a "prismatic block" (reminiscent of a conventional reactor core) or a "pebble-bed" core. The high temperatures enable applications such as process heat or hydrogen production via the thermochemical sulfur–iodine cycle.
  • 902
  • 16 Nov 2022
Topic Review
Proton Exchange Membrane Fuel Cells
Proton exchange membrane fuel cells (PEMFCs) operate by converting the chemical energy in a fuel into electrical energy. The most crucial parameters in the operation process are the temperature, pressure, relative humidity, and air stoichiometry ratio. The classical structure of a PEMFC consists of a proton exchange membrane, anode electrode, cathode electrode, catalyst layers (CLs), microporous layer (MPLs), gas diffusion layers (GDLs), two bipolar plates (BPs), and gas flow channels (GFCs). The mechanical behavior and the conductivity of the protons are highly dependent on the structure of the MEAs.
  • 902
  • 20 Feb 2023
Topic Review
Perovskite Solar Cells with g-C3N4
Perovskite solar cells (PSCs) have attracted great research interest in the scientific community due to their extraordinary optoelectronic properties and the fact that their power conversion efficiency (PCE) has increased rapidly in recent years, surpassing other 3rd generation photovoltaic (PV) technologies. Graphitic carbon nitride (g-C3N4) presents exceptional optical and electronic properties and its use was recently expanded in the field of PSCs. The addition of g-C3N4 in the perovskite absorber and/or the electron transport layer (ETL) resulted in PCEs exceeding 22%, mainly due to defects passivation, improved conductivity and crystallinity as well as low charge carriers’ recombination rate within the device. Significant performance increase, including stability enhancement, was also achieved when g-C3N4 was applied at the PSC interfaces and the observed improvement was attributed to its wetting (hydrophobic/hydrophilic) nature and the fine tuning of the corresponding interface energetics. 
  • 902
  • 26 Apr 2021
Topic Review
Evolution of Access Network Sharing
Network sharing is part of a fundamental principle of statistical multiplexing of link capacity. Regardless of whether the nodes are setting up connections that reserve capacity in the Plain Old Telephone Service (POTS), or sending packets in a connection-less packet-switched network, the overall link capacity is only a fraction of the total interconnection capacity required if all nodes attempted communicating at once. Network sharing also applies to the progressive aggregation of link capacity where the ratio of multiplexing increases in moving from the access towards the core. From the mid-90s’, the concept of sharing was extended to also cover the multi-tenant use of the network, where third party network operators compete with the incumbent national operator, so that the same common infrastructure is shared across multiple competing entities. The degree to which infrastructure is shared is limited, on the one hand by physical and logical boundaries that separate resources, and on the other hand by economic complexities such as settlements, agreements and regulations that complicate the sharing process.
  • 902
  • 27 Oct 2020
Topic Review
Nanostructures Based on Cobalt Oxide
Cobalt oxide (Co3O4) is known to follow the spinel structure as (Co2+)[Co23+O4. The high spin Co2+occupies the interstitial sites of tetrahedral (8a) whereas low spin Co3+are known to occupy the interstitial sites of octahedral (16d) of the close-packed face-centered cubic lattice of CoO.Co2O3. The p-type conductivity of the material (CoO.Co2O3) is known to originate from the vacancies of Co in the crystal lattices or/and excess oxygen at interstitial sites.  Furthermore, 1D nanostructures of Co3O4  have been investigated over the past decades as an active material for chemical analytes detection owing to its superior catalytic effect together with its excellent stability.
  • 902
  • 06 Aug 2021
Topic Review
Digital and Smart Cities
Mobility is notoriously a key aspect of our modern economy and humans' way of life. In an edge situation such as the current coronavirus pandemic, transportation is one of the first affected mechanisms of a city. In our paper, we highlight the potential of operations research and computational intelligence tools for cities' services. The contributions involves aspects of optimization, internet-of-thing and internet-of-value (brought with concepts of Blockchain). When we sum up all these tools, it becomes possible to envision the potential that emerging software and systems can bring to society, associated with the wave of innovation surroundings the smart cities.
  • 901
  • 21 Jan 2021
Topic Review
Homogenization in the Dairy Industry
The homogenization treatment and the main effects responsible for its application in the food industry are defined. It is shown how the main applications have evolved towards the increase of the functionality of food and valorization of waste from the food industry as a consequence of technological development of valves and the higher pressures applied. Finally, high pressure homogenization technology is recognized as a soft and green technology with great potential for use in the food industry.
  • 900
  • 05 Nov 2020
Topic Review
Sustainable Water and Energy Supply
This entry aims to reveal the economic, technical, and environmental impacts of different system configurations (centralized or decentralized, components, and technologies) on transition plans to achieve a higher share of renewable energy and desalination supplies for regions facing water scarcity. The main contribution of this research is the comparative evaluation of on-grid decentralized or distributed renewable-powered desalination systems for sustainable water and energy supply planning. Applying a novel nexus approach, an interactive multi-period planning model is developed to highlight synergies and to identify conflicts of planning both energy and water sectors at the same time as endogenous subsystems of one overall system. For studying these synergies in this study, the pace of technology deployment and the path of decline in overall costs are assumed to be a function of experience and knowledge as two-factor learning curves. Using data from 81 projects, the levelized cost and capacity factor of utility-scale photovoltaic and wind supplies in the Middle East were calculated. The results indicate that a scenario with a decentralized water sector and renewable-powered multiple-effect distillation technology has the best overall performance among the proposed scenarios. The authors consider that the current study provides novel insights: (1) Designing and planning both the water and energy sectors at the same time, (2) detailed representation of short-term operational aspects in long-run planning of the water and energy sectors to capture the inherent variability of renewable energy resources, (3) modeling the water sector with centralized and decentralized on-grid renewable-powered desalination systems, (4) proposing a new methodology to study the synergies and conflicts of designing the water and energy sectors as an integrated system/separated system, and (5) estimating the two-factor learning curves for wind, photovoltaic, reverse osmosis desalination, and multi-effect distillation desalination industries in the Middle East.
  • 900
  • 27 Oct 2020
Topic Review
Kar-go
Kar-go, is an autonomous delivery vehicle, designed and built by British company, Academy of Robotics Ltd, a UK company, registered in Wales. The vehicle uses self-drive / driverless car technology to drive itself to locations where it delivers packages autonomously.
  • 900
  • 18 Oct 2022
Topic Review
Nondestructive Monitoring in RC Elements
The structural and damage assessment of a reinforced concrete (RC) beam subjected to a four-point bending laboratory test is presented. Different nondestructive testing (NDT) techniques have been used with distributed fiber optic sensors (FOS) and acoustic emission (AE) sensors. The recorded AE activity results in good agreement with FOS strain measurements. At different loading steps, digital image correlation (DIC) analysis was also conducted.
  • 900
  • 30 Oct 2020
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