Topic Review
Metal Sulfide Precipitation
Metal sulfide precipitation can efficiently recover several metals and metalloids from different aqueous sources, including wastewaters and hydrometallurgical solutions. 
  • 2.4K
  • 04 Jan 2022
Topic Review
Solid Waste Management in Middle East Arab Countries
Solid waste production, specifically construction waste, in Middle Eastern Arab countries has dramatically increased. This is characterized by several factors, including rapid urbanization, common food wasting habits, diverse culture, lack of proper planning of solid waste processes, insufficient equipment, as well as lack of proper funding. The exponential growth in solid waste generation rates has led to hazards to health and the environment, causing issues related to air and water pollution under the already increasing pressure of climate change.
  • 2.4K
  • 17 Nov 2022
Topic Review
Retrofitting and Strengthening of Structures
In civil engineering since antiquity, structural repair has been a very particular problem. Throughout history, human-constructed buildings have been destroyed due to time, natural disasters, and even building mistakes. In this respect, the field of engineering related to structural reconstruction and recovery seeks to identify methods and techniques to accomplish this important task. The pace of the degradation of concrete buildings throughout the world is frightening. It has now been verified that even if the structural design complies with all particular building code criteria such as concrete quality, cover, and so on, there is still an acceptable high risk of concrete degradation and reinforcing corrosion. Steel corrosion has been identified as the most severe cause of reinforced concrete degradation, capable of causing fractures, spalling the concrete cover, reducing the effective c/s area of the reinforcement, and ultimately leading to collapse. In order to repair and rehabilitate other buildings, this study sought to compile the main ideas, methods, and technologies used by these influential engineers. In fact, this report contains case studies on functional restoration. The document further addresses various types of building, such as pre-stressing, post-tensioning, deployment, and pre-stressing.
  • 2.1K
  • 24 Dec 2022
Topic Review
Classification of the Marine Selective Catalytic Reduction Systems
The marine SCR system is mainly composed of a urea solution injection system, mixer, SCR reactor, measurement system, and soot blowing system. The urea solution injection system is composed of a urea storage tank, urea injection pump, nozzle, valve, and pipeline. Additionally, a static mixer is arranged in the exhaust pipe of the marine SCR system to improve the mixing uniformity of exhaust gas and ammonia gas. 
  • 2.0K
  • 18 May 2022
Topic Review
Sustainable Housing in Rwanda
Baked clay bricks (Impunyu) is the dominant wall construction material in Rwanda. Clay deposits in the country’s lowlands are utilized for baked clay bricks. Despite the ongoing campaign, the use of wood by some local brick producers is unfriendly to the environment. Recent research has called for alternative methods in order to reduce the cost and impact on the environment. Earlier efforts with compressed earth blocks were saddled with weight and a substantial use of cement for good surface texture and adequate resistance against surface erosion. This research explored the potentials of using an appropriate dose of clay (from Muhanzi), volcanic light aggregate (Amakoro, (from Musanze)), and cement to produce unbaked shelled compressed earth blocks (SCEB). SCEB is a compressed earth block with an outer shell and inner core of different cement content or materials, compressed into a unit block. The result is a masonry unit with a higher surface resistance, durability, and desirable architectural effect produced with a 60% reduction in cement content. A weight reduction of 12% was achieved with an optimum content of 33% of the volcanic lightweight aggregate. A cost reduction of 25% was recorded over conventional compressed earth brick walls and a 54% over sand-cement block walls. Possible future trends were also identified with appreciable prospects in earthen architecture. 
  • 2.0K
  • 29 Jul 2021
Topic Review
Carbon Fiber-Reinforced Polymer Composites
Due exceptional properties such as its high-temperature resistance, mechanical characteristics, and relatively lower price, the demand for carbon fiber has been increasing over the past years. The widespread use of carbon-fiber-reinforced polymers or plastics (CFRP) has attracted many industries.
  • 2.0K
  • 10 Jun 2022
Topic Review
Culture in Maintenance Management of Public Buildings
Culture is one of the significant elements that influence the behavior of doing things the right way, without which there is a hindrance to the attainment of set goals. It has also been stated that culture is essential to maintaining public buildings, which is significant to national development. However, the level of abandonment and deterioration of public buildings is high due to a lack of culture among stakeholders in the maintenance process.
  • 1.9K
  • 08 Jun 2022
Topic Review
Eco-efficiency
The term eco-efficiency was first proposed in 1990 by Schaltegger and Sturm. However, it was in 1991 that the World Business Council for Sustainable Development (WBCSD) was responsible for introducing one of the main concepts of eco-efficiency to the world. The term was defined as the delivery of economically competitive goods and services that meet the needs of society in terms of quality of life and that the entire process of manufacturing and availability for consumption, that is, throughout its life cycle, should have the least possible impact on the environment.
  • 1.9K
  • 13 Dec 2021
Topic Review
Odor Measurement Methods
Odor pollution related to industrial activities (e.g., chemical industries, oil and gas extraction and refining facilities, waste treatment and disposal facilities) is nowadays acknowledged as a serious environmental concern. Indeed, odors are currently subjected to control and regulation in many countries. Such regulations rely on the possibility of measuring odors. The methods that have been developed and standardized over the last years to measure odors, thereby including sensorial and instrumental techniques, are here described, thereby focusing on their applicability and limitations.
  • 1.8K
  • 08 Feb 2022
Topic Review
PEC Reactors for Water/Wastewater Treatment
Now and in the coming years, how we use and treat water, greywater and wastewater will become more important. A suitably designed photoelectrocatalytic (PEC) reactor is one potential solution. The photoexcitation of suitable semiconducting materials in aqueous environments can lead to the production of reactive oxygen species (ROS). ROS can inactivate microorganisms and degrade a range of chemical compounds. In the case of heterogeneous photocatalysis, semiconducting materials may suffer from fast recombination of electron–hole pairs and require post-treatment to separate the photocatalyst when a suspension system is used. To reduce recombination and improve the rate of degradation, an externally applied electrical bias can be used where the semiconducting material is immobilised onto an electrically conducive support and connected to a counter electrode. These electrochemically assisted photocatalytic systems have been termed “photoelectrocatalytic” (PEC). The term is stated in the IUPAC Recommendations 2011 as “electrochemically assisted photocatalysis. The role of the photocatalyst is played by a photoelectrode, often a semiconductor”. A short description of photocatalysis is included as it can be beneficial for those unfamiliar with the topic, before moving onto PEC. This entry is adapted from https://doi.org/10.3390/w13091198
  • 1.7K
  • 20 Oct 2021
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