Essays on Crystals

Question #1: Graphical illustration of energy changes during the formation of the nucleus in homogeneous solidification phenomenon.

The solidification phenomenon of a metal starts with the formation of nuclei in a liquid melt, the nuclei forms a stable nuclei in the same melt, and finally formation of the solidified structure of grained crystals. The structure is illustrated in the following diagrams. Figure 1. Solidification process

Question #2: Comparison between homogeneous and heterogeneous nucleation

In the homogenous nucleation, the nuclei are synthesized from metal solidifying atoms. In heterogeneous nucleation, the nucleating agents are the impurity atoms as well as the container surfaces

Question #3: Production of large silicon single crystals

The large silicon single crystals are generated by the use of pure silicon seed crystals in a silicon melt in the Czochralski process.

Question #4: What are a metal alloy and solid solution?

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The crash of Air France 447 is considered the biggest disaster ever to hit Air France and Airbus since the beginning of their venture into this industry. All of the 228 passengers and crew of the flight were killed in this accident (Palmer, 2013). Due to the delay in the recovery of the black box from the ocean bed, the investigations and final report, published by BEA, took nearly three years for completion (Jonathan, 2011). The final investigation revealed that the accident occurred due to the inconsistent data indicated by the FMC (Flight Management Computer System) regarding the fluid ...

Electrophilic Aromatic Substitution to yield 4-Bromoacetanilide

Introduction Halogenation is a common process in organic synthesis. It is used in industrial and research synthesis as halogenated compounds are used for numerous widely used goods, including plastics. The lab aimed to perform monohalogenation of acetanilide. The reaction is specific since it is performed without catalyst. The typical halogenation is realized in presence of Lewis acid. Halogens molecules are electrophilic, and do not actively react. In presence of Lewis acid, the interaction is rather active.2 The lab used catalyst-free halogenation. The acetanilide molecule contains the acylated amine. As a result, the electronic density is shifted towards the amine ...

GEOL1202 Planet

The rock was picked up on crystal beach, Halifax, Nova Scotia, Canada. The rock was on the white sand beach. Because of the abundance of this rock, it is possible the beach sand is a combination of this type of rock, pummeled into sand over thousands of years.

Observations:

The rock is rounded, like a squished tennis ball. It is about the size of the palm of a medium male hand. The rock is white whith small black flecks of another rock type in it. This rock was laying on the beach with hundreds of similar rocks. It seemed to ...

Stone Formation in the Kidney/ Role of Citrate in the Kidneys

Kidney stones are calcified or solidified molecules taking place in the upper urinary tract and the kidney. Kidney stones are usually composed of calcium as oxalate, phosphate, or carbonate. Stone formation in the kidney happens when the amount of mineral salts in the urine becomes saturated, during which the mineral will automatically crystallize (Rao et al., 2011). Stone formation is further facilitated by increasing amount of calcium in urine and dehydration. High levels of calcium in urine can indicate kidney disorder, prolonged incapacitation, hyperthyroidism or overactive thyroid, excessive intake of milk or aluminum and vitamin D. Stone formation in ...

<Institution> Based on the 2013 Annual National Survey on Drug Use and Health, which was conducted by the Substance Abuse and Mental Health Services Administration (SAMHSA), there were approximately 24 million Americans (ages 12 and up) who used illicit drugs a month before the survey was conducted (National Institute on Drug Abuse, 2015). From this figure, 1.5 Americans used cocaine (National Institute on Drug Abuse, 2015). Knowing that many people continue to use prohibited drugs despite the fact that it is associated with many adverse effects, I became interested on this area, specifically on understanding what could help ...

Introduction:

Occupational exposure to silica crystals has long been identified and recognized in most of the industries. There are various industries that involved the silica dusts, where some are highly exposed beyond the threshold limits for the substances. The problem with the occupational exposure of workers to silica crystals are often not taken seriously be employer and employee alike. Exposure to silica in the occupational environment results to health effects such as silicosis and other related diseases. People who are working with these crystals are prone to respiratory effects as well. There is a problem in the safety and health ...

Etienne Malus was the one who discovered polarization back in 1808. The law that is credited to her, the Malus law states that when light passes through an ideal polarizer, the intensity of light will have a value of cos2 θ, theta being the angle of the light source (“Polarization”). In 1920s, Edwin Land is the inventor of the first polarizer (“Polarization”). He also founded the Polaroid company. This was made possible because of the Herapathite crystals, which are needle-like, aligned on a film producing a polarizer. The polarized light that is parallel to the crystals are absorbed, the ones ...

1. Discuss how aquamarine forms and explain the chemical composition (elements)

Aquamarine gemstones are members of the prominent beryl group of minerals. Beryl crystals are among the valued gems that occur naturally. Aquamarine and beryl in general, is composed of atoms of beryllium, aluminium, silicon, and oxygen. The chemical formula for beryl is Be3Al2SiO6 (Scheper 12). Aboriginal rocks facilitate the growth conditions for aquamarine formation. As the plutonic plate condensed, minerals were crystallized to create gemstones like aquamarine. The dimension of the crystal is proportionate to the cooling rate. Large crystals are created when the pace of cooling is extremely slow. In addition, Aquamarine is found in naturally occurring geological ...

The Mobile Phone: Parts and Choice of Materials

The mobile phone is one of the greatest inventions of all time (Guthrie, 2008). It has revolutionized the way people communicate and perform their day to day activities. Cell phones allow remote communication with people in far-away places, including those in other continents. Initially, cell phones were only meant to people to call and send short messages in the form of SMSs. However, cell phones have now advanced and are being used for a wide variety of purposes including taking pictures and videos, listening to music, browsing the internet, playing games, organizing events amongst other uses. The functionalities that a phone ...