408 research outputs found
Evidence-Based Medicine; Climbing a Mountain for a Better Decision-Making
Evidence-Based Medicine is a relatively new term used in medical sittings and Health Information Technology (HIT). It is a form of medicine that integrates practitioners’ expertise with the best available practical evidences to improve better patient care. Evidence-Based Medicine has increasingly been used and incorporated into daily medical practices to overcome the shortcomings in the conventional standard care. The purpose of this literature review is to highlight the importance of Evidence-Based Medicine and how it can act as a crucial tool in decision-making to empower the quality of medical services for better patient outcomes
Chapter 12 Carbonation of mine tailings waste
This chapter introduces general information about the mine tailing waste residues: their sources and properties. It also highlights the carbonation of such residues done with/without pretreatment through single/multiple step(s). It concerns with detailed description of anorthosite, ultramafic, ophiolitic complexes tailing waste residues and red mud with further demonstration about its processes such Bayer, calcination-carbonation showing the effects of different parameters. Finally, the reader finds the practical applications of these carbonated tailing waste residues, where more studies are recommended to enhance their utilization
Chapter 11 Carbonation of cement-based construction waste
This chapter highlighted the concept of cement/concrete carbon cycle and summarizes the utilization studies of such type of materials through mineral carbonation of different types of cement-base construction wastes
Chapter 6 Carbonation technologies
This chapter discusses some selected carbonation processes to identify the stage at which each technology is ready for implementation by using the nine Technology Readiness Levels Available technologies that implemented the multistep aqueous carbonation processes were discussed. These technologies were divided into two groups. The first deals with technologies for natural serpentine carbonation, such as the Nottingham University process (TRL3), the Ã…bo Akademi process (TRL3), the Shell process (TRL7), and the US National Energy Technology Laboratory process (TRL3); while, the second deals with technologies for alkaline waste carbonation (AWC) such as The High Gravity Carbonation (HiGCarb) pilot-scale project in Taiwan (TRL3) for Basic Oxygen Furnace slag, and Mohamed and El-Gamal\u27s Fluidization (MGF) Process (TRL6) for variety of AWC such as cement Kiln dust (CKD), fly ash, and steel slags. Five case studies for the use of the MGF process were presented. These are (a) CKD; (b) EAF steel slag; (c) manufacturing of sewerage pipes from (i) bitumen-based modified elemental sulfur, (ii) crushed sand, dune sand, and carbonated Ladle Furnace (LF) slag as aggregate material; and (iii) carbonated ground granulated blast furnace slag (GGFBS) as a filler; (d) demonstration in actual underground sewerage environment for ordinary Portland cements concrete, as a reference, sulfate resistance cement concrete, and two types of sulfur concrete, one of which was manufactured with modified sulfur cement as well as carbonated fly ash; and (e) demonstration in saline, and variable acidic environments, whereby the products were manufactured using elemental sulfur, modified sulfur cement, sand, and carbonated CKD using the MGF process. Details regarding hydration mechanisms, factors that control the hydration process, optimum operating conditions for the hydration process, carbonation processes, degree of sequestration, and optimum carbonation parameters were discussed. Carbonated products were evaluated using X-ray diffraction analysis, thermo-gravimetric analysis, and scanning electron microscopy. Finally, the potential leachability and long-term stability of carbonated products were evaluated
Chapter 7 Laboratory carbonation methods: testing and evaluation
This chapter is concerned with the carbonation methods, which are used in laboratory studies for mineral carbonations as well as the experimental methods that are used to calculate the carbon uptakes. In addition, the maximum theoretical uptake, carbonation efficiency, and ratio are discussed. Carbonation reactors such as fluidized bed, spouted bed, high gravity rotating bed, ultrasound, and autoclave are presented and discussed. Also, the calcium looping reactor for both calcination and carbonation is included. For all the reactors, the basic operating principles, as well as the carbonation controlling parameters, are highlighted and evaluated
Chapter 10 Carbonation of calcium carbide residue
In this chapter, the background information about the manufacturing of calcium carbide, sources of calcium carbide residue (CCR), chemical and mineralogical properties of CCR, current as well as potential utilization of CCR, current disposal practices, and the different treatment techniques for carbon sequestration and production of viable products for various industrial applications were discussed. The utilization aspects varied from the construction industry to civil works, waste management industry, and future horizons, whereby the production of high value-added products is emphasized through some examples. A newly developed natural carbonation process was discussed. The MGF has many advantages such as (a) the process is fit the recent environmental applications; (b) the ability to optimize the required reaction time; (c) eliminating the need for additional thermal and mineralogical experiments required to determine carbon sequestration efficiency and ensure sustainable use of CO2 during the application process. Indirect carbonation techniques for producing pure calcium carbonate and other valuable products such as xonotlite and calcium formate were discussed. The system-based design approach, where the process is augmented with techniques to prevent aggregation during the carbonation process, such as the jet flow system, and the chemical-based approach, where chemical reagents were used to leach specific metal ions, were evaluated. Finally, the production of CaO-based sorbents using calcium carbide residue (CCR) was discussed. The Ca-looping process was debated and the factors that impact the thermal stability of the produced synthetic sorbents. Modification processes such as hydration treatment, thermal pretreatment, material modification, and incorporation of inert support materials were evaluated with specific examples such as briquette, foaming, copyrolysis, and carbon templating
Chapter 4 Carbonation reaction kinetics
This chapter summarizes the carbonation reaction mechanisms and the available mathematical models that might describe carbonation performance. A variety of models such as shrinking core, progressive conversion, particle-pellet, and unreacted core shrinking models are discussed. It further highlights the derivation steps for several cases based on the determination of the limiting step: the rate-limiting or diffusion-controlling step
Chapter 5 Mineral carbonation
In this chapter, accelerated carbonation technology (ACT) is discussed. Both direct and indirect carbonation processes used in the ACT are highlighted, emphasizing using the alkaline solid waste materials as the feedstock for the carbonation. The principles of accelerated carbonation reaction in view of process chemistry, ion equilibrium in solution, carbonate precipitation, formation of solid carbonates, calcite crystal growth, the thermodynamic stability of formed products, and modeling of reaction kinetics are discussed.rnFactors that affect the carbonation efficiency such as surface activation, flue gas characteristics, nature of the carbonation reactor, the reacting media, and the product themselves are discussed. The following carbonated products are identified and discussed: (a) carbonates-based minerals (soda ash, calcium carbonates, bicarbonate, magnesium carbonates, iron carbonates, etc.); (b) hydroxides-based chemicals, such as calcium and sodium hydroxides; (c) minerals such as hydro-magnesite, calcite, halite, and dolomite that can be used as cementitious materials for cement-based concrete materials; (d) other minerals such as nesquehonite, lansfordite, dypingite and artinite that can be used as aggregates and cementitious materials; (e) chloride-based chemicals, such as HCl, NaOCl, or chlorine-based polymers, such as PVC; and (f) hydrogen.rnThe possible utilization of the carbonated products, such as lower- and higher-end calcium carbonate products, mono-dispersed nanoparticles, silica, and the whole carbonated solid alkaline waste materials, are discussed. Finally, life cycle assessments of several alkaline solid wastes, including ultra-fine (UF) slag, fly-ash (FA) slag, and blended hydraulic slag cement (BHC), in an autoclave reactor are discussed
Chapter 14 Carbonation of cement kiln dust
The sources and characteristics of various types of ash and waste produced in the cement industry, such as CKD, cement bypass dust, ordinary Portland cement, and recycled concrete aggregate, are discussed. Current CKD utilization in civil works, geotechnical applications, roads and pavement structures, treatment of hazardous wastes, waste containment barriers, permeable reactive barriers for groundwater remediation, and wastewater neutralization are discussed. Also, the potential use of CKD for carbon sequestration is evaluated. Hydration of CKD and the newly formed hydrated products, such as hydrated lime [C–H], calcium silicate hydrates [C3S2H3], calcium aluminate hydrates [C3AH6], calcium aluminate trisulfate hydrate [C6AS3H32] or the calcium aluminate mono-sulfate hydrate [C4ASH18], are discussed. Also, CKD carbonation methods such as (a) Mohamed and El Gamal fluidization (MGF) process; (b) batch carbonation process; (c) column carbonation process; (d) rotating tube furnace carbonation process; (e) ultrasonic carbonation process; and (f) indirect carbonation, were discussed. Finally, CKD kinetic modeling, which describes the carbonation reaction, is discussed with emphasis on the type of carbonation reactor (static vs. dynamic)
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