• 건축역사연구
• /
• 제18권4호
• /
• pp.63-79
• /
• 2009

Since the 1970's, UNESCO and ICOMOS have adopted or emphasized on the principles of historic preservation. One of them is what to require a repair have not to be repaired beyond the limits of the features and techniques to have been born in those days of establishment. On the premise, this paper is to examine the materials and technique of lime plaster work in order for roof ridge, and for bond paste of stones and bricks in government constructions in the late of Joseon dynasty(17~19c). The result of this examination will come up with a basic conformity in the case of repairing the building established in the late of Joseon dynasty. This paper is carried out for the proper repair and restoration of architectural cultural properties. Construction reports and other documents in those days are examined for the study. Following conclusions have been reached through the study. The components of old plaster mixtures which agglutinate stones each other were quicklime, perilla oil, and paper fiber. The components of old plaster mixtures which point joint of black bricks consisted of slaked lime, perilla oil, paper fiber, and cereal starch. These components were the same as coat surface of roof ridges. In the case of times, one of the following sand, white clay, sap of boiled elm bark was added to these components for the purpose of high efficiency. These materials and techniques which applied to plaster work of those buildings had developed in the process of making royal tombs. But these materials and techniques were quite different from the present.

• KIEAE Journal
• /
• 제9권1호
• /
• pp.77-83
• /
• 2009

In this experiment, we used different addition ratio of the pigment and straw, to improve the decorative effect of the finishing touch while finding the kinds of clay colors taking on many sophisticated images, through the comparison between the various colors and textures of the surface. (1) To test the plaster material, added were the pigment of Red, Yellow, Black, and Green by the percentages of 0.5, 1, 1.5, 2, and 2.5, respectively, followed by the analysis of the color changes of the plaster material using the Photoshop (RGB). The results showed the bigger the addition ratio of the red color is, the higher the numeral values of RGB after it dried. However the brightness after drying didn't showed a big difference depending on the addition ratio. With the addition of the yellow pigment, the color difference between after and before drying was bigger in the order of Blue, Green and Red; the brightness increasingly rose while the saturation changed little. (2) When we scratched the plaster surface with U and V shape carving knives, the U knife didn't make a clean shape digging around the clay plaster material but with smooth textures, while the V knife made a clean cut, which represents its readily use in terms of the decorative function of the clay plaster. (3) In an experiment the surface texture was tested with different lengths and additions ratio of the straw, addition of 2cm straw by 1, 2, and 3% presented the most appropriate surface of the plaster.

• 한국정밀공학회지
• /
• 제18권9호
• /
• pp.101-109
• /
• 2001

The simulated die casting process in which the traditional plaster casting process is combined with rapid prototyping technology is being used to produce Al, Mg and Zn die casting prototypes. Because of lower mechanical properties induced by the large grain structure and incomplete filling, conventional plaster casting is not suitable for the simulated die casting process. A plaster casting process with pressurized vibration was developed for the simulated die casting process[5]. In this paper, numerical simulation for the filling stage of the process has been performed to show the effect of the pressurized vibration for complete filling. Treatment of boundary condition based on the finite element method has been proposed for imparted pressurized vibration in the plaster casting process.

• 한국세라믹학회지
• /
• 제31권10호
• /
• pp.1107-1114
• /
• 1994

Although various theories have been presented on the mechanism of setting retardation of plaster in addition to organic admixtures. The purpose of this paper is that Hydration studies of plaster of paris in the presence of carboxylic acids under alkalinity are examined in the coordination chemistry. Setting of plaster of paris is retarded by the addition of carboxylic acids except oxalic acid. And setting of plaster of paris contained 5 wt% of Ca(OH)2 is also retarded by the addition of above-mentioned carboxylic acids. The degree of retarding effect under alkalinity is found to be a function of the number of the functional group and the length of carbon chain of carboxyl acids. These reasons are attributed to the soluble complex formation, that is calcium complex formation between calcium ion and carboxylic acids. The author's proposal was confirmed by the results of electrical conductivity measurement. The formation of calcium complex was surpported by IR spectra.

• 대한치과의사협회지
• /
• 제13권2호
• /
• pp.133-136
• /
• 1975

The autor studied skin reactions and their incidences among 130 dental students and dentists to 2% Iidocaine HCI, 2% procaine HCI, direct resin, plaster of paris, zinc oxide-eugenol cement, and adhesive plaster by Patch test. The results of the studies are as follows: 1. Eighteen cases out of 130 revealed slight positive reaction toa 1 or 2 allergens. 2. Lidocaine HCL showed 1 case, procaine HCL 4 cases, direct resin 4 cases, Z.O.E. cement 1 case, adhesive plaster 13 case, and plaster of paris showed none. 3. Two delayed reaction were detected after 48 hours, one of which reacted both lidocaine HCL and direct resin, and the other one was a case of adhesive plaster.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제18권4호
• /
• pp.771-777
• /
• 1996

This study was undertaken to access the effect of toothash combined with plaster of Paris in the filling of jaw defect and the substitution as new bone during the follow up period. We used the toothash and plaster after the cyst enucleation, the apicoectomy, the extraction of supenumerary tooth with ratio of 2 : 1 by weigh. 15 consecutive patients were evaluated retrospectively. Complications were swelling, perforation, infection and treated without problems using incision & drainage, aspiration, antibiotic treatment, 2ndary buccal flap. The follow-up period ranged from 28 to 35 months. Based on radiographic and clinical observation, it may be concluded that toothash and dental plaster of Paris($CaSo_4\;{\cdot}\;1/2H_2O$) are useful for bone substitute.

• KIEAE Journal
• /
• 제7권3호
• /
• pp.57-62
• /
• 2007

Most of current building materials are made of organic compounds or at least made with chemical treatments. Though easy to use and comparatively pay less, those materials are generally not enviornmentally sound. VOC is one of harmful effects. On contrary, natural materials such as soil are usually eco-friendly, and environmentally sustainable as well if not treated in autoclaves. Acoustica materials made of such environmentally sound and sustainable could be widely used. It is aimed to prove that soil based materials could be effectively used in acoustical fields rather than the other usual materials. Experiments with various types of soil blocks and soil plaster were performed. It is proved that the soil plaster has better apsorption features than cement plaster. Soil blocks have higher absorption cofficients than soil plaster, due to the thickness, and the absorption characteristics can be controlled by the design of the blocks.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제16권2호
• /
• pp.130-136
• /
• 1994

Toothash and plaster of Paris (Calcium sulfate) have been studied for bone substitute through experimental studies and clinical studies. Toothash is like resorbable hydroxyapatite. Plaster of Paris is resorbable and biocompatible. The toothash combined with plaster of Paris has the advantages of individual characteristics. The authors used this composite material in the jaw defect filling. In operation, we could manage this implant material easily and remove the dead space. During the followup period, this composite material was resorbed gradually and substituted as new-forming bone from the surrounding tissue. Complications were minor and treated completely without problems.

• Journal of the Korean Wood Science and Technology
• /
• 제41권5호
• /
• pp.406-414
• /
• 2013

This study aims to date wooden coffins excavated from graves in Shinnae-dong, Seoul, South Korea, using dendrochronology. The species of woods used to make the coffins were identified as Pinus densiflora S. et Z., one of the major conifers in Korea. Of 12 graves, 10 were successfully dated using various red-pine chronologies of South Korea. Due to the absence of the last-formed tree ring before felling, the number of sapwood rings, used to obtain likely cutting dates, had to be estimated. The terminus post quem for two coffins without plaster frames were AD 1548 and AD 1571, respectively. Eight coffins with plaster frames yielded estimated dates from AD 1664 to AD 1799. The tree-ring dates indicated that the coffins with plaster frames in Shinnae-dong were constructed approximately 100 years later than those without plaster frames.

• Advances in environmental research
• /
• 제2권1호
• /
• pp.35-49
• /
• 2013

Research work on removal of fluoride from water, referred to as water defluoridation, has resulted into the development of a number of technologies over the years but they suffer from either cost or efficiency drawbacks. In this work, enhancement effects of phosphate and silicate on defluoridation of water by low-cost Plaster of Paris (calcined gypsum) were studied. To our knowledge, the influence of silicate on defluoridation was not reported. It was claimed, that the presence of some ions in the treated water samples, was decreasing the fluoride removal since these ions compete the fluoride ions on occupying the available adsorption sites, however, phosphate and silicate ions, from its sodium slats, have enhanced the fluoride % removal, hence, precipitation of calcium-fluoro compounds of these ions can be suggested. Percentage removal of $F^-$ by neat Plaster is 48%, the electrical conductance (EC) curve shows the typical curve of Plaster setting which begins at 20 min and finished at 30 min. The addition of phosphate and silicate ions enhances the removal of fluoride to high extent > 90%. Thermodynamics parameters showed spontaneous fluoride removal by neat Plaster and Plaster-silicate system. The percentage removal with time showed second-order reaction kinetics.