• Journal of the Korean Society for Precision Engineering
• /
• v.3 no.1
• /
• pp.40-49
• /
• 1986

Crack, craze and void are common defects which may be found in the bulk of polymeric materials such as either themoplastics or thermosets. The healing phenomena, autohesion, of these defects are known to be a intrinsic material property of various polymeric materials. However, only a few experimental and theoretical investigations on crack, void and craze healing phenomena for various polymeric materials have been reported up to date [1, 2, 3]. This may be partly due to the complications of healing processes and lacking of appropriate theoretical developments. Recently, some investigators have been urged to study the healing phenomena of various polymenic materials since the significance of the use of polymer based alloys or composites has been raised in terms of specific strength and energy saving. In the earlier published reports [1, 2, 3, 4], the crack and void healing velocity, healing toughness and some other healing mechanical and physical properties were measured experimentally and compared with predicted values by utilizing a simple model such as the reptation model under some resonable assumptions. It seems, however, that the general acceptance of the proposed modeling analyses is yet open question. The crack healing processes seem to be complicate and highly dependent on the state of virgin material in terms of mechanical and physical properties. Furthermore, it is also strongly dependent on the histories of crack, craze and void development including fracture suface morphology, the shape of void and the degree of disentanglement of fibril in the craze. The rate of crack healing may be a function of environmental factors such as healing temperature, time and pressure which gives different contact configurations between two separated surfaces. It seems to be reasonable to assume that the crack healing processes may be divided in several distinguished steps like stress relaxation with molecular chain arrangement, surface contact (wetting), inter- diffusion process and com;oete healing (to obtain the original strength). In this context, it is likely that we no longer have to accept the limitation of cumulative damage theories and fatigue life if it is probable to remove the defects such as crack, craze and void and to restore the original strength of polymers or polymer based compowites by suitable choice of healing histories and methods. In this paper, we wish to present a very simple and intuitive theoretical model for the prediction of healed fracture toughness of cracked or defective polymeric components. The central idea of this investigation, thus, may be the modeling of behavior of chain molecules under healing conditions including the effects of chain scission on the healing processes. The validity of this proposed model will be studied by making comparisons between theoretically predicted values and experimentally determined results in near future and will be reported elsewhere.

• Journal of Conservation Science
• /
• v.31 no.1
• /
• pp.75-86
• /
• 2015

A scale Armor is usually excavated in a scattered form weakened by corrosion after its burial. Therefore, they should be brought into the indoor in a safe environment for the on-site conservation treatment as it was excavated. They should be placed on a stable support with a reinforced base in the indoor treatment. In this process, the bottom surface which can not be observed after the conservation treatment is placed for a record by actual survey and photography. But this method had a limit on figuring out the whole aspects of the artifact. For compensating the defect, duplication of the artifact was considered as an alternative method for the previous two methods in the case of conservation of the scale Armor from Jinyoung 2-Area, Gimhae. Neck guard was excavated in a distorted form by the earth pressure, and was hard to recognize the original shape. However, whole real material of its original form was secured through the combination of each duplicated lamellae. Throughout the application of the duplication technique in the process of conservation of scale Armor and neck guard, it could secure the real material of the bottom surface and elevate the understanding of the artifact. Moreover, a constitution of the armor could be identified more effectively.

• Korean Journal of Heritage: History & Science
• /
• v.53 no.2
• /
• pp.140-155
• /
• 2020

The purpose of this study is to examine historical wall repair details through analysis of repair data and administrative documents of the Paradise Conservation of Gangjin Muwisa Temple. In addition, the purpose of the project is to examine the differences and commonalities between the materials and construction technology used in the building's walls. The data for repair work conducted in 1935, 1956, and 1982~3 was analyzed and the results of the research were as follows. First, data for the wall construction conducted in 1935 during the dismantling repair showed that the interior structure of the wall was found to follow that of the original, but the first, second, and final layers used different materials. The composition material of the wall consisted of clay, lime and sand, the second layer used sand and plaster, and the last layer used plaster and seaweed paste. Second, the structure of the wall interior, which was found during the 1956 repairs, consisted of wood woven horizontally and vertically. It was confirmed that this had been installed diagonally using a rope. Third, the 1982~3 repair work confirmed that the wall's interior construction conformed to the original method. The lime-sand wall was formed by mixing slacked lime, sand, soil, fodder, and seaweed grass. Fourth, when the various repairs are considered as a whole, it is clear that the interior structure of the wall was made more than 1900 years ago, and the material used in the wall changed in 1935. Fifth, the materials used for each repair differed, but each project had a common view of cultural heritage repair principles in sections that stated the significance of each project.

• Korean Journal of Heritage: History & Science
• /
• v.44 no.3
• /
• pp.92-111
• /
• 2011

This study focus on the restoration stone selection of break-out part based on material characteristics analysis and the conservational safety diagnosis using various nondestructive techniques for Jungdong and Banjukdong Stone Auariums. As a result, the original rocks of the stone aquariums body are porphyritic granodiorite with magnetite-series having igneous lineation, microcline phenocryst, veinlet and basic xenolith. As a result of the provenance presumption of the host rock, a rock around Gamgokri area in Nonsan City was identified the genetically same rock. Therefore, the rock is appropriate for restoration materials of the break-out part. The deterioration assessment showed that the stone aquariums were highly serious scaling, scale off and blackening. Particularly, the front face of Banjukdong stone aquarium needs reinforcement of structural crack (760mm) caused from igneous lineation of biotite. Blackening contaminants on the stone aquariums surface occurred by combining iron oxide, manganese oxide and clay mineral. Also, major factors of efflorescence contaminants were identified as calcite (Jungdong stone aquariums) and gypsum (Banjukdong stone aquariums). The physical characteristics of stone aquariums appeared that the original and new stone is third (moderately weathered) and second grade (slightly weathered), respectively. This study sets up an integrated conservation system from material analysis to restoration stone selection and conservational safety diagnosis of Jungdong and Banjukdong stone aquariums.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.3
• /
• pp.208-223
• /
• 2014

Since the recent restoration of the Sungnyemun gate (South gate of Seoul) which was burnt down in 2008, there were dispute about the application of traditional technique for the conservation of cultural heritage. In this research, the definition of traditional technique for cultural heritage conservation is thought and mentioned. In general, the understanding of traditional technique is based on the idea of 'tradition'. Tradition is not defined as a 'eternal doctrine existence', but a 'development of succession' and a 'living existence'. Thus 'traditional performance and craft as intangible cultural heritage' is defined as 'intangible' which also makes it difficult to define the 'original form/state' from 'the conservation of the original form' which is a major principle of cultural heritage. In case of Korea, if the 'traditional technique as intangible cultural heritage' is put into application to cultural heritage conservation, the unclear definition will cause many problems in the restoration/conservation site. This is because the site will apply this technique without any discussion of the range and limitation of 'traditional technique'. This means there will be the lack of discussion for the conservation of the cultural heritage which will not have a strict criteria for the allowable range of usage for the 'traditional material' using the vaguely defined 'traditional technique'. In this study, these application issues of the traditional technique were also considerecl, comparing the development of international wnservation principles. As a result, the conservation of 'traditional technique as intangible cultural heritage' is important, but the 'technique left inside the tangible cultural heritage' which is the 'material which is carrying the technique when it was firstly built' has more importance to preserve and need to be in the major considerations.

• Conservation Science in Museum
• /
• v.27
• /
• pp.1-22
• /
• 2022

A chimi(a roof ridge decoration) excavated from the Busosan Temple Site in Buyeo was restored in 1978 at the Buyeo Museum. The gypsum restoration material had deteriorated over time and part of it was seriously damaged and unable to bear the weight of the chimi. The chimi features traces of emergency treatment revealing that the inside of the body and some portions of the tail were reinforced several times using epoxy resin. A condition survey performed in preparation for its transfer for an exhibition found the lower body and wings of the chimi to be highly vulnerable and it was determined that the chimi needed further restoration. The dismantling of the chimi for restoration revealed several elements that provide clues to the production techniques applied by its makers, so they were subjected to inspection. This study explores the production techniques used in the chimi from the Busosan Temple Site that were revealed during the process of dismantling it for restoration. The chimi was inspected using 3D scanning and its rigid vertical shape was restored to a natural form based on the production techniques identified during the dismantling process. The existing restoration material was replaced to improve durability. 3D printed elements were produced based on 3D modelling and were joined to the original chimi to correct its shape and fill in the missing parts, restoring the chimi to its original appearance.

• Journal of Conservation Science
• /
• v.38 no.2
• /
• pp.166-179
• /
• 2022

A test piece was produced using deteriorated pine tree for the conservation treatment of woodblocks cultural heritage, and weight change, color change and penetration diffusion characteristics of the test piece according to the application of Dammar, Wax, Paraloid B-72, Animal glue and H.P.C treatment agent. As a result, it was confirmed that Dammar is the most suitable treatment agent for the strengthening of the material while maintaining the original color of the wood. A test piece was produced using deteriorated porous natural wood, which the damage condition is similar to that of woodblocks cultural heritage and the main tree of woodblocks cultural heritage based on above result, and the application of each Dammar concentration (2%, 5%) and wetting of each Dammar concentration (10%, 15%) were conducted in order to find out the application concentration and treatment method of Dammar, and weight change, penetration diffusion characteristics, etc. were observed. As a result, it was found that the Dammar 2% application was the best as an effective method for the strengthening of the material while maintaining the original color of the wood. Therefore, it is judged that Dammar 2% application is most suitable for the strengthening treatment of woodblocks cultural heritage with severe insect damage and degradation.

• Journal of the Society of Disaster Information
• /
• v.18 no.4
• /
• pp.899-907
• /
• 2022

Purpose: Although many studies on seismic fragility analysis of general bridges have been conducted using machine learning methods, studies on curved bridge structures are insignificant. Therefore, the purpose of this study is to analyze the seismic fragility of bridges with I-shaped curved girders based on the machine learning method considering the material property and geometric uncertainties. Method: Material properties and pier height were considered as uncertainty parameters. Parameters were sampled using the Latin hypercube technique and time history analysis was performed considering the seismic uncertainty. Machine learning data was created by applying artificial neural network and response surface analysis method to the original data. Finally, earthquake fragility analysis was performed using original data and learning data. Result: Parameters were sampled using the Latin hypercube technique, and a total of 160 time history analyzes were performed considering the uncertainty of the earthquake. The analysis result and the predicted value obtained through machine learning were compared, and the coefficient of determination was compared to compare the similarity between the two values. The coefficient of determination of the response surface method was 0.737, which was relatively similar to the observed value. The seismic fragility curve also showed that the predicted value through the response surface method was similar to the observed value. Conclusion: In this study, when the observed value through the finite element analysis and the predicted value through the machine learning method were compared, it was found that the response surface method predicted a result similar to the observed value. However, both machine learning methods were found to underestimate the observed values.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.2
• /
• pp.4-19
• /
• 2014

In Joseon dynasty, Gongsin-Gyoseo(Royal Edicts rewarding meritorious vassals) was issued for the reward of the contribution to the specific event of the nation. The family decided as vassals succeeded this Gongsin-Gyoseo as the family treasure to later generations. When one happened to lose this caused by an unavoidable situation such as war in this process, there were a few cases of reissuing of Gongsin-gyoseo by the nation. The confirmative reissued Gongsin-gyoseo among Gongsin-gyoseo that descended down by now are three pieces which is Park dongnyang Hoseong Gongsin-Gyoseo, Gu goeng Jeongsa Gongsin-Gyoseo, and Park jung Jeongsa Gongsin-Gyoseo. This research considered the form and mounting about these three pieces. It was indicated that the reissued Gongsin-Gyoseo was produced following the same form with the original Gongsin-Gyoseo, that is pyeongchul(moving to next lines) and daedu (writing one or two letters ahead compared to the first letter) and so on. But, it was indicated that the change of the position of the vassals in the reissued time was reflected compared to position of the original Gongsin-Gyoseo. In case of Jeonsa Gongsin-Gyoseo, it was indicated that it was 'Wonjongdaewang-whi' since the original Gongsin-Gyoseo was 'Jeongwongun-bu' and the reissued time he became the father of King Injo. Also, it was confirmed that the case of deprivation because of conspiracy such as 'Kim jajeom, Kim ryeon, Sim kiwon, Sim kisung' was produced as the original document and deleted with black ink stick. It was newly confirmed while the original Gongsin-Gyoseo was produced by a designated writer from the nation, the reissuance was written by a writer from the family of the vassals. Since the mounting of Gongsin-Gyoseo could be changed according to the favor and technique of the craftsman participated in the practical production such as Baezeopjang and economical situation of the country supplying the material, the mounting of these three Gongsin-Gyoseo should be different from the original mounting, especially because of the loss of the original by the Manchu war of 1636. The comparison result of Gongsin-Gyoseo produced in the same period with the original issued one in the record of the related Uigwe (a collection of documents from the Joseon Dynasty), the reissued one seems to be larger in the form or ratio of the mounting compared to the first issued one. First of all, the width of Byunah was expanded as twice bigger, center and both side Hoejang also was bigger as over 2cm, and the below Hoejang was expanded as 10cm, and the ratio of the upper Hoejang and the below Hoejang was wider as 1.5 times and the reissuance was 1:1 ratio. The bisect of upper shaft in Park dongnyang Hoseong Gongsin-Gyoseo is assumed as the form of an equilateral triangle, not a half-moon shape of the present, and Gu goeng and Park jung Jeongsa Gongsin-Gyoseo will be the form whose bisection form is same but the size is smaller. Chuksu is confirmed that the size is not changed significantly. Osaekdahoe can be assumed that the width was smaller compared to the first issued one. The 3 pieces of the reissued versions provide the clue of the verification for the form of the mounting of Bosa Gongsin-Gyoseo in the same production period. In the situation that the mounting of the production time was not confirmed among the currently descended Bosa Gongsin-Gyoseo, they can be very important materials.

• Cartoon and Animation Studies
• /
• s.33
• /
• pp.317-341
• /
• 2013

Found Footage Film has been increasingly addressed between film and visual art world in the age of rapid media change. With regards to this self-conscious found footage filmmaking, narrative structures are unraveled to relate new stories, images are removed from their original context only to reappear in a different context, new layers that alter the meaning are added, stereotypes from Hollywood movies are exposed, and new montages are used to destroy the illusion of the medium itself. The physical properties of the original material are also emphasized or altered in order to add a new meaning. The starting point of this study is the recognition of the origin of found footage film. It traces back to the found object from primitive impulse and found art from Dada and surrealism. Many found footage films have been at least partly inspired by Duchamp's ready-mades. These films use footages that the filmmakers did not shot, and even footage that was never intended as art. This essay deals with the found footage practices and interrogates the aesthetic implications by the concept of self-reflexivity. Self-reflexivity means consciousness turning back on itself, and found footage film is about films which call attention to themselves as cinematic constructs. It breaks with art as illusionism and exposes their own factitiousness as textual constructs. Furthermore, the inevitable mortality of celluloid and temporal reconstruction of original film will be treated. Recentely, many attention has been given to role of Found Footage Film. I hope to add the understanding of the artistic found footage film with this study.