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Topic Review
Doping (Semiconductor)
In semiconductor production, doping is the intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical and optical and structural properties. The doped material is referred to as an extrinsic semiconductor. A semiconductor doped to such high levels that it acts more like a conductor than a semiconductor is referred to as a degenerate semiconductor. In the context of phosphors and scintillators, doping is better known as activation. Doping is also used to control the color in some pigments.
  • 1.0K
  • 08 Nov 2022
Topic Review
Thermophotovoltaic Cell
Generally, waste heat is redundantly released into the surrounding by anthropogenic activities without strategized planning. Consequently, urban heat islands and global warming chronically increases over time. Thermophotovoltaic (TPV) systems can be potentially deployed to harvest waste heat and recuperate energy to tackle this global issue with supplementary generation of electrical energy.
  • 1.0K
  • 29 Nov 2021
Topic Review
High-Performance Laser Scribing of Thin Film Solar Cells
The development of thin-film photovoltaics has emerged as a promising solution to the global energy crisis within the field of solar cell technology. However, transitioning from laboratory scale to large-area solar cells requires precise and high-quality scribes to achieve the required voltage and reduce ohmic losses. Laser scribing has shown great potential in preserving efficiency by minimizing the drop in geometrical fill factor, resistive losses, and shunt formation. However, due to the laser induced photothermal effects, various defects can initiate and impact the quality of scribed grooves and weaken the module’s efficiency. In this regard, much research has been conducted to analyze the geometrical fill factor, surface integrity, and electrical performance of the laser scribes to reach higher power conversion efficiencies.
  • 1.0K
  • 26 May 2023
Topic Review
Bimetallic Ni-Based Catalysts CO2 Methanation
CO2 methanation has recently emerged as a process that targets the reduction in anthropogenic CO2 emissions, via the conversion of CO2 captured from point and mobile sources, as well as H2 produced from renewables into CH4. Ni, among the early transition metals, as well as Ru and Rh, among the noble metals, have been known to be among the most active methanation catalysts, with Ni being favoured due to its low cost and high natural abundance. However, insufficient low-temperature activity, low dispersion and reducibility, as well as nanoparticle sintering are some of the main drawbacks when using Ni-based catalysts. Such problems can be partly overcome via the introduction of a second transition metal (e.g., Fe, Co) or a noble metal (e.g., Ru, Rh, Pt, Pd and Re) in Ni-based catalysts. Through Ni-M alloy formation, or the intricate synergy between two adjacent metallic phases, new high-performing and low-cost methanation catalysts can be obtained.
  • 1.0K
  • 12 May 2021
Topic Review
Vanguard TV3
Vanguard TV3, also called Vanguard Test Vehicle Three was the first attempt of the United States to launch a satellite into orbit around the Earth. Vanguard 1A was a small satellite designed to test the launch capabilities of the three-stage Vanguard and study the effects of the environment on a satellite and its systems in Earth orbit. It was also to be used to obtain geodetic measurements through orbit analysis. Solar cells on Vanguard 1A were manufactured by Bell Laboratories. At its launch attempt on December 6, 1957, at Cape Canaveral Air Force Station , the booster ignited and began to rise, but about two seconds after liftoff, after rising about four feet (1.2 m), the rocket lost thrust and fell back to the launch pad. As it settled the fuel tanks ruptured and exploded, destroying the rocket and severely damaging the launch pad. The Vanguard satellite was thrown clear and landed on the ground a short distance away with its transmitters still sending out a beacon signal. The satellite was damaged, however, and could not be reused. It is now on display at the National Air and Space Museum of the Smithsonian Institution. The exact cause of the accident was not determined with certainty, but it appeared that the fuel system malfunctioned. Other engines of the same model were modified and did not fail.
  • 1.0K
  • 25 Oct 2022
Topic Review
Hexapod Robots
The static stability of hexapods motivates their design for tasks in which stable locomotion is required, such as navigation across complex environments. This task is of high interest due to the possibility of replacing human beings in exploration, surveillance and rescue missions. For this application, the control system must adapt the actuation of the limbs according to their surroundings to ensure that the hexapod does not tumble during locomotion.
  • 1.0K
  • 25 Aug 2021
Topic Review
Pedestrian–Vehicle Interaction at Unsignalized Crosswalks
A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), to generate a document that supports the development of future research, compiling the various studies focused on the analysis of the pedestrian-vehicle interaction at unsignalized crosswalks. Firstly, 381 studies were identified by applying the search protocol in the database sources; however, only nine studies were included in this review because most of the studies are not focused on this type of crosswalks or have not considered the micro-simulation perspective. For each study, an analysis of the used methodology for data collection was carried out, in addition to what type of model it was applied, including the variables that represent the PVI (Pedestrian-Vehicle Interaction). The outcomes obtained by this systematic review show that although the video camera observation technique is the most used, it is possible to complement them with other tools to add specific field information. Additionally, variables such as the adjacent yields, speed variables vehicles, pedestrian attitude, and the number of pedestrians waiting at the crossing were those most used in the cellular automata model or micro-simulation, which are the commonly developed models to simulate this interaction.
  • 1.0K
  • 25 Apr 2020
Topic Review
Demand Response Products
Demand response refers to planning, implementing and monitoring the use of electricity to generate changes in the consumers' demand profile to adapt to different needs. Thus, a Demand Response Product can be defined as the contractual framework which guarantees that the service provided by flexible consumers satifies the minimum requirements of the related service to the final user of such flexibility (network operator, energy trader, aggregator, etc.) Demand Response is a key element of future power systems due to its capacity to defer grid investments, improve demand participation in the market and absorb renewable energy source variations. In this regard, Demand Response can play an important role in delivering ancillary services to power systems.
  • 1.0K
  • 18 Mar 2021
Topic Review
Indoor Environmental Quality
A discussion of sustainability in architecture cannot be meaningfully carried out without the inclusion of most buildings’ central purpose, namely the provision of indoor environments that are accommodating of occupants’ needs and requirements. To this end, building designers and operators are expected to demonstrate compliance with codes and standards pertaining to indoor environmental quality (IEQ). However, the majority of conventional IEQ standards, codes,and guidelines have a single-domain character, in that they address IEQ in terms of a number of isolated domains (i.e., thermal, visual, acoustic, air quality). In this context, the present contribution explores the current state of multi-domain IEQ evaluation approaches and the necessary conditions for their further development and application. Toward this end, a number of common building rating schemes were selected and analyzed in detail. The results of this assessment imply the necessity of both short-term improvements of the existing schemes in terms of the transparency and plausibility of the applied point allocation and weighting strategies and the fundamental need for a deeper empirically grounded understanding of the nature of occupants’ perception of and behavior in the built environments.
  • 1.0K
  • 23 Oct 2020
Topic Review
Structure of Miruk-Jõn Hall Kumsan-Sa Temple in Korean
The Miruk-jõn Hall of Kumsan-sa Temple (reconstructed in 1635, National Treasure No. 62) is in Gimje-si, Jeollabuk-do in the southern region of Korea. The Miruk-jõn Hall is a pagoda hall with a diminished structure, and the interior is thought to have been built in an ancient style. Miruk-jõn is a three-storied building, and the pillar spacing is five ken (2) (bays) for the first story, five ken for the second story, and three ken for the third story. In the second story, both Hatamas (the last interval between pillars) are narrowed.
  • 1.0K
  • 26 Apr 2022
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