Vacuum hot table

Some Techniques of Textile Conservation Including the Use of a Vacuum Hot Table... 

Textiles, as are many objects of art, are subject to the deteriorative effects of dirt, acidity, light, humidity, and mishandling. The steps by which they are conserved are detailed, including a discussion of the problems inherent in their restoration. The use of the vacuum hot table—a recent technique—is exemplified in the treatment of embroideries and two Civil War flags, and the use of adhesives is discussed in regard to this technique. 

Today, instead of the Japanese rice past method, I am using the vacuum hot table (2) with a heat-activated adhesive, which is also harmless and reversible. I am stressing here the use of the vacuum hot table in the treatment of textiles as it is a fairly recent technique for us. The vacuum hot table was designed for painting conservators and used by them in re-lining old paintings. The first published account I know of in the use of this table for textiles is by Sheila Landi (3) of the Victoria and Albert Museum in London. Another reference is by Kathryn Scott... 

An embroidery with very high tension is not a suitable problem for the vacuum hot table. The vacuum causes the piece to become absolutely flat and will make permanent creases and transform the puckers into creases. This does not apply to all embroideries, however. I have successfully done some on the vacuum hot table. 

The answer was to put the piece back on the vacuum hot table, this time adhering the almost invisible silk to the face of the textile. This was not as pleasing aesthetically as I would have liked, but at least the piece is safe and will last for many years. Otherwise it would have totally disintegrated in a few years. In another Peruvian piece of similar structure, there was no problem because the warps were strong enough to withstand the sewing down of loose surface wefts which were not held by the adhesive. 

In conclusion, the use of the vacuum hot table is not the answer to every textile conservation problem. It is one useful tool in the repertory. Each work of art, by definition, is unique. Therefore, each textile must be individually treated, using the method most applicable to the problems. 

Vacuum Hot Table, Peter Koch, Apparatebau, Hannover, West Germany. 

Table 2. Commercial Grades of Vacuum Hot-Pressed Beryllium, Composition by wt...

In order to improve the comprehensive mechanical properties of Zr02 ceramic material, the influence of different particle size and contents of TiB2 and AI2Q3 powders on the microstructure and mechanical properties of Zr02 nano composite ceramic tool and die material is investigated. Zr02 nano composite ceramic tool and die material is prepared with Vacuum hot pressing technique at 1 450 °C for 60 min at 30 MPa. The results were shown in the Table 1. 

Because of their complementary character, TLC and HPLC can be used simultaneously for the easier solution of complicated separation problems. Thus, the determination of cap-saicinoids in fruit of hot pepper Capsicum annuum L. by spectrophotometry, TLC and HPLC has been reported. Samples were homogenized with acetone followed by a homogenization with acetone-petroleum ether 1 1 v/v until the tissue was nearly white. The extract was filtered and the acetone was washed out by small amounts (0.01 ml) of water. The ether phase was dried with anhydrous NajSC and concentrated in vacuum at 30°C. The extract was separated on silica TLC plates using a petroleum ether-acetate-methanol (75 20 5) mobile phase. The capsaicinoids were scraped off the layer and further analysed by HPLC. The Rp values of carotenoids and capsaicinoids are listed in Table 2.2. It was stated that the method can be employed for the measurement of carotenoids in hot peppers [19]. 

---