Essays on Resin

Click Chemistry describes the biocompatible reactions that are high yielding, that are very simple to perform, have wide scope, that need no chromatography to remove their byproducts and that can be conducted in easily removable solvents. The synthesis of first triazole was reported by Arthur Michael in 1893. In the 20th century, Huisgen discovered the catalyst of copper, 1,3-dipolar cycloaddition which required the temperature of 100 degree Celsius. This reaction of copper is a highly versatile reaction which does not require any specific reaction conditions and can easily be performed with various solvents, wide temperature range and pH, ...

Rapid prototyping is a set of various techniques that is usually used for fabricating a model or a sample using 3D computer aided design. The rapid prototyping allows prompt and effective collection of data necessary to produce a sample or a particular detail. Historically, the method was used to convert drawings into fabricated samples and details. However, the entire group of techniques is comparatively recent, as the first available options became available with the advancement and penetration of digital machines. The development in rapid prototyping is a result of progressing technological advancement and a high demand in machine tool ...

Rapid prototyping is the most convenient way to get a replica of a three-dimensional design CAD-generated 3D application way.

These physical models can be only aesthetic and useful for the study of the potential market of the product, or they may meet some or most of the mechanical requirements which would have the final piece, offering, in this case, the possibility to perform functional tests and approval before there even preliminary molds. That man made his hands the means that would shape the objects that determine their evolution, devised object, the object designed: tools, utensils, art, and beauty, among others. Use of science was done to create the elements that should give matter and harmony with their creations. ...

Complications of Removable Implant Supported Prostheses

Introduction The two main complications that result from removable implants are biological and mechanical/technical complications. There is need to assess and interpret data on the incidence of complications, both biological and technical with caution. Berglundh, Persson, and Klinge (2002), found that implant loss was the most common problem, while technical complications were observable in about 60-80% and biological complications – 40-60% of the studies they evaluated. According to Sadowsky (2007), there are no specifications on the length, distribution, and number of implants; however the suggestion for non-palatal coverage designs should be a minimum of 4 implants. In case of risk ...

With four treatment options, the patient must undergo a thorough consultation with the clinician, covering each restoration type. Each treatment presentation will include the benefits and drawbacks the that particular method, risks and/or impediments associated with placement, complications that can arise after placement and daily maintenance protocols. The presentations must be clear and concise and devoid of scientific terminology that may not be recognized by the patient. To enhance understanding, it is recommended that the presentations utilize models, photographs and/or drawings representing the final product; images of previous cases can be used if they comply with all patient confidentiality ...

Summary

While all the components of a brake system are important, it is imperative to acknowledge that some components play significant roles in the system as compared to others. One such component is the brake pad. In most cases, the brake pad is referred to as the friction material. It is responsible for generating the friction which opposed the movement of the wheel thus causing a stop to the movement of the automotive. This report is aimed at selecting a section or component of the brake system and presents its modification. As a consequence, the report highlights and discusses the ...

Explain Hardness of Water

Explain Hardness of Water The water that occurs in nature always contains salts, which exist in water as positive and negative ions. The salinity of fresh water is 1000 mg/L (1L of water contains 1000 mg of various salts or ions). The typical cations present in natural water are sodium, potassium, calcium and magnesium; the most common anions are chloride, sulfate, bicarbonate, nitrates, etc. Hardness of water refers to presence of calcium and magnesium ions. When water is heated, the reaction (Tebbutt, 1999):

takes place. Calcium carbonate, unlikely other salts, is insoluble and forms precipitate. The precipitate is ...

Lignin Chemistry

Lignin History Lignin is a plant-derived biopolymer with several applications. It is considered an effective alternative to chemically synthesized plastics that pose serious environmental problems during manufacture and disposal. Lignin is often obtained as a byproduct in paper and pulp manufacture. Lignin has to be dissolved to obtain cellulose from wood. In 1838, Anselme Payen discovered that wood contained cellulose, and oxidizable coatings (later called lignin) that bind the cellulose together (McCarthy and Islam, 2000). This coating material could be removed from wood after acid treatment and washing with an aqueous alkali solution (McCarthy and Islam, 2000). Later, several ...

The questions of birth control have always troubled mankind. The search for methods of contraception and abortion by doctors doing started in the ancient world. Throughout the history of mankind abortion is one of the oldest problems of medical ethics, philosophy, law and theology. The mention of abortion is found in ancient Chinese writing more than 4,600 years ago. There is evidence that the ancient inhabitants of Australia tore the membranes to cause miscarriage. Moreover, the women of East Africa caused an abortion with special wooden sticks. This paper is dedicated to clarification of the methods of birth ...

Uranium (U) element was discovered by a German chemist, Heinrich Klaproth, in 1789. Uranium is a radioactive element with an atomic weight of 238.02891 and an atomic number of 92. The uranium element initially discovered by Heinrich was an oxide, uranium oxide. A French chemist, Eugène-Melchoir Péligot, was the first person to produce pure uranium by reacting it with potassium in a heated platinum crucible. The element’s radioactive properties were established in 1896 by a French physicist known as Antoine Henri Becquerel. Currently, uranium can be extracted from various ores such as carnotite (K2(UO2)2VO4· ...

The ultimate goal of every medical practitioner is to provide the most efficient services to the patients. It happens to dentists who look forward to giving satisfactory and durable restorations. For a fruitful repair, Monolithic Zirconia crowns are used. A Zirconia crown is a type of ceramic crown that is worn to give a better appearance of the tooth that has been disfigured or stained for quite some time. The crown is made from a durable material that cannot be rejected by the human body (Stober et al., 2014). Zirconia crown is also used for other medical purposes such ...