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Passivhaus
Passivhaus or Passive House buildings are low-energy buildings in which the design is driven by quality and comfort, hence achieving acceptable levels of comfort through post-heating or post-cooling of fresh air. Additionally, Passivhaus building design follows the Passivhaus design criteria, as described in the Passive House Planning Package (PHPP). This article aims to introduce the Passivhaus background, development, and basic design principles. Finally, it also presents a brief description of the performance of Passivhaus buildings. 
  • 2.1K
  • 18 Apr 2022
Topic Review
Kairos
Kairos (καιρός) is an Ancient Greek word meaning the right, critical, or opportune moment. The ancient Greeks had two words for time: chronos (χρόνος) and kairos. The former refers to chronological or sequential time, while the latter signifies a proper or opportune time for action. While chronos is quantitative, kairos has a qualitative, permanent nature. Kairos also means weather in Modern Greek. The plural, καιροί (kairoi (Ancient and Modern Greek)) means the times. Kairos is a term, idea, and practice that has been applied in several fields including classical rhetoric, modern rhetoric, digital media, Christian theology, and science.
  • 2.1K
  • 07 Oct 2022
Topic Review
Biogas
Biogas refers to a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. Biogas is a renewable energy source. Biogas can be produced by anaerobic digestion with methanogen or anaerobic organisms, which digest material inside a closed system, or fermentation of biodegradable materials. This closed system is called an anaerobic digester, biodigester or a bioreactor. Biogas is primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulphide (H2S), moisture and siloxanes. The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat. Biogas can be compressed, the same way as natural gas is compressed to CNG, and used to power motor vehicles. In the United Kingdom , for example, biogas is estimated to have the potential to replace around 17% of vehicle fuel. It qualifies for renewable energy subsidies in some parts of the world. Biogas can be cleaned and upgraded to natural gas standards, when it becomes bio-methane. Biogas is considered to be a renewable resource because its production-and-use cycle is continuous, and it generates no net carbon dioxide. As the organic material grows, it is converted and used. It then regrows in a continually repeating cycle. From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released, when the material is ultimately converted to energy.
  • 2.1K
  • 22 Nov 2022
Topic Review
Polarization Holography
Polarization holography has the unique capacity to record and retrieve the amplitude, phase, and polarization of light simultaneously in a polarization-sensitive recording material and has attracted widespread attention. Polarization holography is a noteworthy technology with potential applications in the fields of high-capacity data storage, polarization-controlled optical elements, and other related fields.
  • 2.1K
  • 23 Jan 2021
Topic Review
Optical Diffraction Tomography
Optical Diffraction Tomography (ODT) is an emerging tool for label-free imaging of semi-transparent samples in three-dimensional space. Being semi-transparent, such objects do not strongly alter the amplitude of the illuminating field.
  • 2.1K
  • 28 Jan 2022
Topic Review
Drinking Bird
Drinking birds, also known as insatiable birdies, dunking birds, drinky birds, water birds, dipping birds, and “Sippy Chickens” are toy heat engines that mimic the motions of a bird drinking from a water source. They are sometimes incorrectly considered examples of a perpetual motion device.
  • 2.1K
  • 25 Nov 2022
Topic Review
The Nitrogen Bond
The nitrogen bond in chemical systems occurs when there is evidence of a net attractive interaction between the electrophilic region associated with a covalently or coordinately bound nitrogen atom in a molecular entity and a nucleophile in another, or the same molecular entity. It is the first member of the family of pnictogen bonds formed by the first atom of the pnictogen family, Group 15, of the periodic table, and is an inter- or intra-molecular non-covalent interaction.
  • 2.1K
  • 25 Mar 2022
Topic Review
Ionizing Irradiations in Food Industry
The ionizing radiations are particles or waves containing enough energy to ionize the matter when coming in contact. Their mode of action in living cells involves either the direct destruction of nucleic acid or by creating free radicals that can attack the cellular components. This cellular destruction and inactivation can be used to reduce the microbial burden in food items to increase the shelf life and safety of food, meanwhile maintaining the quality of the product. Although this technology is accepted by more than 60 countries, some consumers are reluctant to buy such products thinking that radiations might have modified their food which can also induce changes in their body after consumption. The proper scientific communication regarding the safety of ionization irradiations can change consumer behavior, and it requires the collaboration of all stakeholders in the food production chain. 
  • 2.1K
  • 05 Nov 2020
Topic Review
Fiscal Year
A fiscal year (or financial year, or sometimes budget year) is used in government accounting, which varies between countries, and for budget purposes. It is also used for financial reporting by businesses and other organizations. Laws in many jurisdictions require company financial reports to be prepared and published on an annual basis, but generally do not require the reporting period to align with the calendar year (1 January to 31 December). Taxation laws generally require accounting records to be maintained and taxes calculated on an annual basis, which usually corresponds to the fiscal year used for government purposes. The calculation of tax on an annual basis is especially relevant for direct taxation, such as income tax. Many annual government fees—such as Council rates, license fees, etc.—are also levied on a fiscal year basis, while others are charged on an anniversary basis. Some companies—such as Cisco Systems—end their fiscal year on the same day of the week each year, i.e. the day that is closest to a particular date (for example, the Friday closest to 31 December). Under such a system, some fiscal years will have 52 weeks and others 53 weeks. The calendar year is used as the fiscal year by about 65% of publicly traded companies in the United States and for a majority of large corporations in the UK. It's the case in many countries around the world with a few exceptions, for example, Australia, New Zealand, and Japan. Many universities have a fiscal year which ends during the summer to align the fiscal year with the academic year (and, in some cases involving public universities, with the state government's fiscal year), and because the university is normally less busy during the summer months. In the northern hemisphere this is July to the next June. In the southern hemisphere this is calendar year, January to December. Some media/communication-based organizations use a broadcast calendar as the basis for their fiscal year. The fiscal year is usually denoted by the calendar year in which it ends, so United States federal government spending incurred on 14 November 2022 would belong to fiscal year 2023, operating on a fiscal calendar of October–September.
  • 2.1K
  • 11 Oct 2022
Topic Review
Supergiant Star
Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars spans from about 3,400 K to over 20,000 K.
  • 2.1K
  • 12 Oct 2022
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