How common is Ice used in dentistry?5 answersIce is commonly used in dentistry for various purposes such as reducing post-endodontic pain, controlling discomfort during local anesthesia injections, and providing topical anesthesia. Studies have shown that ice massage can significantly decrease dental pain intensity by 50% or more, comparable to the effects of transcutaneous electrical stimulation and acupuncture. Additionally, the application of ice for topical anesthesia of oral mucosa has been found to be an effective alternative to lidocaine 5% gel, with lower pain ratings during buccal injections. Furthermore, the use of cold saline during root canal irrigation has been effective in reducing postoperative pain in cases of irreversible pulpitis with apical periodontitis. These findings highlight the common and beneficial use of ice in various dental procedures for pain management and patient comfort.
How can ice be used as a mold for casting?5 answersIce can be used as a mold for casting by a process called ice templating or freeze casting. This process involves shaping macroporous materials by exploiting the unidirectional crystallization of ice. It has been widely applied to various classes of materials, including ceramics and polymers. The process involves pouring ceramic slurries or colloidal solutions around an ice pattern and then curing them at sub-freezing temperatures. The ice pattern is then removed, leaving behind a solid mold with a porous structure. The success of this process depends on various parameters such as formulation, process conditions, and the mechanical properties of the materials used. Understanding and controlling these parameters are critical for optimizing the structure and properties of the ice templated materials.
Impurities in the ice cube?5 answersImpurities in ice cubes are expelled from the growing ice lattice into the unfrozen portion of the solution during the freezing process. These impurities can be freeze-concentrated in veins between ice crystals, (micro)pockets within the ice structure, or on the ice surface. The location of impurities within the frozen sample is important as it affects their reactivity and availability. Impurities located close to the ice surface are more easily accessible to gas-phase oxidants and can be released back into the environment more readily compared to impurities buried in the frozen bulk. The compartmentation and phase speciation of impurities in ice are essential for understanding their fate. Environmental scanning electron microscopy (ESEM) allows for direct observation of impurities in ice samples, providing information about their location and compartmentation in dynamically changing conditions. The microstructural location of impurities in natural polycrystalline ice can be examined using controlled preferential sublimation in a low-vacuum SEM, which reveals concentrated impurities at the triple junctions, grain boundaries, and grain interiors. Impurities in polar ice can influence the physical properties of the ice and their localisation inside the microstructure is still under debate. Dust particles and sulfates are commonly found as impurities in ice cores, with their mineralogy varying with depth.
How do second phase materials affect ice?3 answersSecond phase materials have a significant impact on ice. In the context of refrigeration, a bottom mount refrigerator utilizes a thermal battery or phase change material to increase energy efficiency and compartment sizes. This phase change material aids in ice production by removing heat from the water in the ice maker. In the field of air-conditioning, an ice storage system uses different phase-change materials to store low-temperature heat energy via phase change, changing liquid into solid. This system minimizes electric power consumption and electric charge. In the context of spacecraft thermal control systems, phase change materials, such as water, can store thermal energy during peak heat loads and release it during minimum heat loads, reducing system mass. In the realm of pavement engineering, phase change materials incorporated into asphalt pavements can prevent freezing temperatures and assist in melting snow and ice, enhancing the thermal response of the pavement.
What is devitrification?4 answersDevitrification is the process of transforming an amorphous material into a crystalline structure. It involves the development of crystalline phases from the amorphous matrix. Devitrification can occur in various materials, including silicate glasses, metal alloys, and plant tissues. The stability of the amorphous phase and the nature of the crystalline phases formed during devitrification depend on factors such as temperature, composition, and the presence of alloying elements. In some cases, devitrification can be controlled or induced for specific purposes, such as the regeneration of plant seedlings or the improvement of crucibles used in semiconductor and photovoltaic applications. Analytical techniques like X-ray diffraction, electron microscopy, and thermal analysis are commonly used to study the devitrification behavior of different materials.
Can we mix dry ice with boric acid and bti?1 answersDry ice can be mixed with boric acid and BTI (Bacillus thuringiensis and/or Bacillus sphaericus) for combating mosquito larvae. However, it is important to note that the abstracts provided do not specifically mention the mixing of dry ice with boric acid and BTI. Therefore, it is recommended to consult additional sources or scientific literature to obtain more information on the compatibility and effectiveness of this mixture for mosquito control.