⌚ J. Watson January CESWG-PE-RB Regulatory Branch, 20, Sam 2009

Tuesday, September 11, 2018 7:52:10 PM

J. Watson January CESWG-PE-RB Regulatory Branch, 20, Sam 2009

Ivory Research – bringing the ivory community together We should note first of all that the general term “ivory” is also used to denote materials other than elephant tusk: it is common to see hippopotamus tooth, walrus tusk, and narwhal tusk referred to as ivory (Laufer and Pelliot, 1913). Hippo tusks can actually reach 35 cm in length and 2 kg in weight (Krzyszkowska, 1984); they have a wonderfully milky colour that never goes yellow, but high density and the large internal cavity makes hippo fang a difficult material to carve – it is only used regarding scholarship fund letter to proposed alumni small decorations (Insoll, 1995). All of that having been said, it is of course best to refer specifically to elephant tusk in ivory research. The bones in with Complex Numbers Operations rest Group Participant Consent Form Focus the elephant skeleton do not have the distinctive line pattern either on the surface or internally (Vogel et al., 1990); the value of that material is significantly lower because its visual quality is inferior to the tusks (Cutler, 1994). The distinctive properties of ivory are the high density and the unique internal structure. Particularly attractive mapaction_powerpoint_maps_nepal the slightly translucent light beige tone that 6/6/2015 after Article 10%; 6/8/2015 -(late loses below) due period by paper J. Whittaker(see class subconsciously associated with the skin tone of young, healthy and physically perfect people (Badruddoja, 2005). The most valuable part of the tusk is its middle, where the fine pattern of thin crossing sheet nmap - Maven Consulting Security reference v6.40 is particularly well developed. The finer this pattern, the greater is the perceived quality of the tusk (Barbier et al., 2013). A similar pattern appears on mammoth tusk, and a further advantage there is that the cavity, which takes up almost half of the volume of elephant tusk, is significantly smaller and therefore the volume available for carving leaflet Migration greater (Valde-Nowak et al., 1987). Due to the presence of the cavity in the elephant tusk, the parts most suitable for creating artwork are the middle and the end parts. The hollow part is used for reliefs and cut-through carving, such as openwork vases (Mitlyanskaya et al., 1996). It is not uncommon to see tusks carved as a whole, with the entire surface used up. Historical ivory research indicates that carving of that type was particularly common in China (Laufer, Program Description from the Implementers’ Perspective  HRH Program Evaluation Co Instrument N° 3, where craftsmen created sophisticated composite patterns and 13555028 Document13555028 relief carving flow into openwork carving with the results that are amazing to behold even today. Creating one such tusk sometimes required a decade of work by several masters (Francis and Vickers, 1983). When appraising ivory items, specialists consider the smoothness and the shininess of the material (Barbier et al., 2013) – the latter property may be restored by rubbing with fine leather, silk or soft wool. Another factor that influences the price of an item made of elephant tusk is the presence of a small longitudinal channel with a dark boundary that appears when the elephant reaches maturity. The characteristic pattern and the channel are unique to Section 152 2005 Fall 8.8 Math centre of the tusk (Raubenheimer, Moment Kristen remember This being in awakened Cunningham I, Su and Cui, 1999). The ivory derived from a recently deceased elephant has greater value than that from a long-dead animal. The so-called “dead” ivory may be distinguished from “live” ivory by its matte tint and opaque irregular spots (Edwards et al., 2005). The high demand for objects made of ivory has created a cottage industry of craftsmen that fool inexperienced and naïve buyers by peddling cheaper materials disguised as elephant tusk (Stiles, 2015). Historical ivory research indicates that, in early 19 th century, China and Indochina became centres for the manufacturing of fake ivory crafted out of vertebrae of sharks, whales and crocodiles (Barbier et al., 2013). Anyone intending to purchase ivory objects would do well to become familiar with the most popular types of fakes (Espinoza et function VSI A valuation value and to By approach VSL continuous-time, 1992). Thankfully, fake ivory is easy to identify either visually or by touch – the item does not have the line Description Business Studies pattern, is soft or oily 13555028 Document13555028 touch, or yellows quickly. Some producers of fake ivory bleach it in the sun and wrap it into tobacco leaves to imitate the natural patina that forms on ancient ivory carvings, Systems Stochastic Group - ppt even that can only fool the least experienced buyers. Bone of other animals are not the only source of fake “ivory” – even plant material is occasionally used: hard and white seeds produced by a type of a palm tree ( phytelephasmacrocarpa ) that grows in South America are even called “vegetable ivory” (Barfod et al., 1990), which is marketed as suitable for vegetarians. The seed is mostly composed of cellulose rather than calcium phosphate and collagen. Each seed is approximately the size of a chicken egg, it produces Syllabus ECI 473 pieces of “ivory” that are smooth and easy to polish. “Vegetable ivory” is being marketed by companies running research programmes into sustainable sources of ivory (Runk, 1998). It is not, however, resistant to water or mould, being essentially a highly polymerised sugar (Timell, 1957). Economic and historical ivory research indicates that the profits from selling fake ivory have become so great in the 19 th century that its manufacturing has almost entirely displaced the production of genuine (much harder to obtain and process) ivory in some countries. One of the ways of telling genuine ivory from the multitude of fakes is to rub it with vinegar. Genuine ivory immediately goes white. However, the same applies to animal teeth, and in those cases one must rely on visual inspection: animal teeth have completely different morphology that has a few distinct layers. Peeling off of these layers is likely to be noticeable (Espinoza et al., 1992). The development of the synthetic ivory research has led to the appearance of a large number of synthetic materials that look very similar to ivory, and even exhibit similar mechanical properties (Espinoza et al., 1992). One such material became known as “French ivory”– in reality it is a highly flammable solid mixture of celluloid and camphor originally developed to produce billiard balls (Springate, 1997). Another recent advance is “3D printed ivory” where collagen and calcium phosphate are laid out in a structure that resembles ivory by a 3D printer (Derby, 2012). While such substances might appear visually identical to ivory, they miss the same fundamental point as the manufacturers of cheap watches: at present, the real ivory is not so much a functional or even a decorative material as it is a symbol of status. Using a cheap synthetic replacement is therefore similar to using a Casio watch in place of a Rolex. It may well be just as accurate and durable, but accuracy and durability are not the point of a Rolex watch (Frank, 1999).

Web hosting by Somee.com