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Topic Review
Cereal Crop Residues in Green Concrete Technology
Concrete is mainly employed as a construction material. Due to the manufacturing of cement and the extent of concrete usage, numerous environmental issues and water suction have presented challenges. There is an immediate need to overcome these problematic issues by substituting natural resources with wastes and by-products of different biological processes in the production of concrete in order to make green concrete. Green concrete provides a relatively low-impact material to satisfy potential concrete demand and offers a cheaper, robust and highly reliable alternative that could fulfil future construction requirements in an environmentally safer way. Green concrete could be an alternative material that could replace those used in conventional methods of construction and help make a further step towards environmental sustainability and a circular bioeconomy.
  • 412
  • 07 Sep 2022
Topic Review
CH4 and NOx from Marine LNG Engine Exhaust
Compared to diesel, liquefied natural gas (LNG), often used as an alternative fuel for marine engines, comes with significant advantages in reducing emissions of particulate matter (PM), SOx, CO2, and other pollutants. Promoting the use of LNG is of great significance for achieving carbon peaking and neutrality worldwide, as well as improving the energy structure.
  • 188
  • 24 Jul 2023
Topic Review
Chalk
Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. Flint (a type of chert) is very common as bands parallel to the bedding or as nodules embedded in chalk. It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is often deposited around larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint). Chalk, as seen in Cretaceous deposits of Western Europe, is unusual among sedimentary limestones in the thickness of the beds. Most cliffs of chalk have very few obvious bedding planes unlike most thick sequences of limestone such as the Carboniferous Limestone or the Jurassic oolitic limestones. This may indicate very stable conditions over tens of millions of years. Chalk has greater resistance to weathering and slumping than the clays with which it is usually associated, thus forming tall, steep cliffs where chalk ridges meet the sea. Chalk hills, known as chalk downland, usually form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is well jointed it can hold a large volume of ground water, providing a natural reservoir that releases water slowly through dry seasons.
  • 5.2K
  • 29 Nov 2022
Topic Review
Challenges in Recycling of Multi-Material Composites
Transformation of waste into resources is an important part of the circular economy. The recovery of materials in the most effective way is crucial for sustainable development. Composite materials offer great opportunities for product development and high performance in use, but their position in a circular economy system remains challenging, especially in terms of material recovery.
  • 399
  • 17 Oct 2023
Topic Review
Challenges to Promote Sustainability in Urban Agriculture Models
Urban agriculture (UA) can be used as an action to promote sustainability in cities and inform public health policies for urban populations. Despite this growing recognition, its implementation still presents challenges in countries in the Global North and Global South. 
  • 556
  • 13 Feb 2023
Topic Review
Challenges to Renewable Energy Transition in China
Climate change and energy issues have become the prominent global challenge and a major concern of China. China’s energy sector, which heavily relies on fossil energy, especially coal, is the largest contributor to China’s carbon emissions. According to the International Energy Agency (IEA), China’s energy consumption accounts for nearly 90% of China’s total CO2 emissions in 2020. The carbon neutrality target poses a huge challenge to China’s energy system, causing energy transition to be the key to the overall decarbonization of China’s economy and society.
  • 2.7K
  • 07 Dec 2022
Topic Review
Changing Food Consumption Patterns and Land Requirements
The food consumed and the household size determine the land requirement for food. Continued population growth without improved living standards and adequate food production output per hectare will further exacerbate food insecurity and land shortage in Nigeria.
  • 731
  • 19 Jan 2022
Topic Review Video
Chaos and Order in the Atmosphere
The Lorenz 1963 and 1969 models have been applied for revealing the chaotic nature of weather and climate and for estimating the atmospheric predictability limit. Recently, an in-depth analysis of classical Lorenz models (LMs) and newly developed, generalized Lorenz models suggested a revised view that “The atmosphere possesses chaos and order; it includes, as examples, emerging organized systems (such as tornadoes) and time varying forcing from recurrent seasons”, in contrast to the conventional view of “weather is chaotic”. The revised view focuses on distinct predictability and time varying multistability. Distinct predictability suggests limited predictability for chaotic solutions and unlimited predictability (or up to their lifetime) for non-chaotic solutions. To support the revised view, multistability (for attractor coexistence) and monostability (for single-type solutions) are first illustrated using kayaking and skiing as an analogy. Additionally, this entry provides a list of non-chaotic weather systems and a short list of suggested future tasks.
  • 1.2K
  • 29 Nov 2022
Topic Review
Characterisation of Thunderstorms with Multiple Lightning Jumps
Several works have shown that lightning jumps are precursors of severe weather in deep-convective thunderstorms. Since 2017, the Meteorological Service of Catalonia has operationally run an algorithm that identifies lightning jumps (LJs) in real time. It has resulted in being an effective tool for nowcasting severe weather with a lead time between 15 min and 120 min in advance. This time can be of high value for managing emergencies caused by severe phenomena or heavy rains. The present research focused on the events’ analysis in which more than one lightning jump occurred, searching for those elements that differentiate single warning cases. Thunderstorms producing LJs were divided into two main categories, depending on the number of jumps triggered during the life cycle. Besides, both classes were split into two main sub-types, based on the level of the LJ that occurred. Multiple LJ thunderstorms produce more Level 2—related to severe weather—jumps than Level 1—small hail or intense precipitation—while in the case of a single LJ, the opposite behaviour occurs. In general, multiple LJ thunderstorms with at least one Level 2 jump are the more intense and have a higher vertical development. Finally, lineal and well-organised thunderstorms are the more common modes in those intenser cases. 
  • 419
  • 28 Jan 2022
Topic Review
Characteristic Features of Skouries and Other Porphyry-Cu-Au+Pd±Pt Deposits
Many giant porphyry Cu-Au, Cu-Mo, and Mo-W deposits extend from the Pacific Rim to the Mediterranean and Carpathian system in Europe, the Himalayas, China, and Malaysia. However, only certain porphyry Cu-Au deposits, associated mostly with alkaline-type intrusions, are characterized by significant Pd and Pt contents, particularly in high-grade bornite–chalcopyrite and/or flotation concentrates. Such porphyry deposits include those in British Columbia, Colorado, in the Santo Tomas II deposit, the Philippines, the Skouries porphyry deposit, Greece, Elatsite, Bulgaria, the Kalmakyr deposit, Uzbekistan, the Grasberg deposit, Indonesia, Ok Tedi, Papua New Guinea, the Mamut deposit, Malaysia, and the Bajo de la Alumbrera, Argentina.
  • 110
  • 17 Nov 2023
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