What is physical vapor deposition?5 answersPhysical vapor deposition (PVD) involves the removal of atoms from a solid or liquid through physical means, followed by their deposition onto a nearby surface to create a thin film or coating. Techniques like thermal evaporation, sputtering, laser ablation, and cathodic arc-based emission are utilized to release atoms for deposition. The process can include sputtering from a target in a plasma deposition chamber, where the substrate is maintained at a controlled temperature. PVD methods, such as magnetron sputtering, are commonly used for depositing metallic and compound thin films. The equipment used in PVD can be designed to enhance film uniformity by uniformly spraying reacting gas onto the substrate surface, thus improving film quality and reducing production costs.
What will be the future applications of Laser Direct metal deposition?5 answersThe future applications of Laser Direct Metal Deposition (LDMD) are promising and diverse. LDMD technology enables the preparation of high-performance coatings, three-dimensional direct manufacturing, and re-manufacturing of parts. It is particularly valuable in industries like automotive and energy sectors for coating, repair, and building near net shape geometries. Additionally, LDMD, a form of Directed Energy Deposition (DED), is recognized for its potential in repairing high-value components, designed materials, and production processes. The use of metal powders in LDMD, analogous to Laser Metal Deposition (LMD), is crucial for quality control and the production of various industrial products. Furthermore, advancements in LDMD technology focus on defect suppression, performance improvement, and material selection to achieve the desired functionality, making it a key technique for surface treatment in mechanical engineering and aerospace industries.
What are the primary factors contributing to scale deposition in industrial processes?4 answersScale deposition in industrial processes is primarily influenced by factors such as supersaturation, nucleation, contact time, temperature, hydrodynamic conditions (velocity, pipe diameter, Reynolds number), surface roughness, and the type and concentration of dissolved ions. The presence of dissolved salts in a supersaturated solution promotes scale formation, and the precipitation of a crystalline substance onto the site of scale formation requires supersaturation, nucleation, and adequate contact time. The effectiveness of scale inhibitors in reducing or inhibiting scale formation depends on factors such as contact time, temperature, solution pH, additive concentration, and structure. Understanding the mechanisms of scale formation and identification of the scale type are crucial for developing effective mitigation and inhibition strategies.
What are the direct air technology approaches?4 answersDirect air capture (DAC) is an important solution to curb global warming and enable a circular economy. DAC technologies use engineered contactors filled with chemicals to repeatedly capture CO2 from the air and release high purity CO2 that can be stored or used. There are two main approaches to DAC: solid sorbents and liquid solvents. Solid sorbents and liquid solvents are used as sorbent materials to efficiently capture CO2 from the air. The development of breakthrough sorbents that efficiently capture and release CO2 for sequestration is a key research direction. DAC processes can be scaled up by learning-by-doing and driving down costs. Electro-swing and humidity-swing carbon capture are new developments that can decrease the energy footprint of DAC and make it more affordable. The captured CO2 can be valorized and converted into cyclic carbonates using commercially available basic ionic liquids.
What is direct air capture?5 answersDirect air capture (DAC) is a process that involves removing CO2 directly from the atmosphere. It is an important strategy for reducing CO2 concentration and mitigating climate change. DAC technologies use various sorbent materials, both liquid-based and solid-based, to capture CO2 from the air. These sorbents efficiently capture CO2 and can release it for sequestration. DAC faces challenges such as high costs and low CO2 concentration in the atmosphere. However, researchers are exploring ways to overcome these challenges and accelerate the development of DAC systems. Some novel approaches include the conversion of captured CO2 into cyclic carbonates using basic ionic liquids, the use of Lewis acid-base interaction-derived hybrid sorbents with high CO2 capture capacities, and the investigation of solid DAC adsorbers for indoor air capture. Life cycle assessment (LCA) is also used to evaluate the environmental potential of DAC technologies.
How direct air capture unit is made?5 answersA direct air capture (DAC) unit is made by using different approaches and materials. One approach involves using a vacuum chamber with an adsorber structure housed inside. The chamber has a circumferential wall structure that is closed by inlet and outlet axial walls, allowing gas to circulate through the chamber when open and closing the interior space when closed. Another approach involves using a device with a membrane that is permeable to air and contains a solid state CO2 sorbent. The device has sorption and regeneration chambers, and air flows through the membrane from an inlet to an outlet in the sorption chamber. Stripping gas is flowed through the membrane into the regeneration chamber, and CO2 is discharged from an outlet in the regeneration chamber. These approaches provide efficient and low-cost solutions for capturing CO2 directly from air.