Conservation Of Cultural Relics Research Articles

Research on the current status and trend of the application of machine learning in the field of literature and museums- Based on CiteSpace

With the development of the world economy and the rapid arrival of the digital era, machine learning technology continues to develop and is widely used in various fields, including the field of literature and museums. The article analyses and researches the relevant literature through citespace visualization software with machine learning research in the field of literature and museums as the main hotspot. It is found that in recent years, the attention to machine learning in the field of literature and museums has shown a significant growth trend, and the machine learning technology is concentrated in the conservation of cultural relics, museum management, cultural heritage protection, heritage identification, etc., which realises the automation, intelligence and personalization of the field of literature and museums and greatly improves the efficiency of work. Finally, this study summarises the current trend of machine learning research in the field of cultural and museums, and puts forward the outlook for the future development direction. By deeply analysing the current situation of machine learning research in the field of literature and exposition, it provides useful references and insights for future researchers, and helps to promote the in-depth development of the intersection between the field of literature and exposition and machine learning, and promotes the innovation and cooperation of related research.

Metabarcode insights into the airborne fungal diversity in the indoor and outdoor environments in archives from Yunnan, Southwestern China.

Monitoring dynamics of airborne fungal species and controlling of harmful ones are of vital importance to conservation of cultural relics. However, the evaluation of air quality and the community structure characteristics of microorganisms, especially fungi, in the atmosphere of archives is in a stage of continuous exploration though more than 4,000 archives were constructed in China. Seventy-two air samples were collected in this study under different spatial and weather conditions from the archives of Kunming Medical University, located in the Kunming metropolitan area, Yunnan province, southwestern China. A total of 22 airborne fungal classes, 160 genera and 699 ASVs were identified, the species diversity is on the rise with the strengthening of air circulation with the outside space, and thus the intensive energy metabolism and activity were found in the spaces with window and sunny weather, except for the higher lipid synthesis of indoor samples than that of outdoor ones. Furthermore, there were significant differences in fungal community composition and abundance between sunny and rainy weathers. A considerable number of species have been identified as indicator in various environmental and weather conditions of the archives, and temperature and humidity were thought to have significant correlations with the abundance of these species. Meanwhile, Cladosporium and Alternaria were the dominant genera here, which may pose a threat to the health of archive professionals. Therefore, monitoring and controlling the growth of these fungal species is crucial for both conservation of paper records and health of archive professionals.

Industrial computed tomography for three-dimensional cultural relic model reconstruction based on L1-αL2+TV norm minimization

Industrial computed tomography (ICT) has emerged as a valuable tool for the conservation of cultural relics since it enables the extraction of information about the internal structure of artifacts without causing any damage. However, sparse and finite angle projection computed tomography (CT) often generates images with a large number of artifacts caused by insufficient data. This paper introduces a new cone-beam CT hybrid model based on compressed sensing (CS) theory and total variance (TV) denoising using the Split Bregman algorithm to address this problem, for the first time using compressed sensing theory for CT reconstruction of cultural relics. The model combines the L1 and L2 norms and optimizes the total variance of the image as the objective function. To enhance the reconstruction of L1-L2, the paper employs the continuation strategy of α and proposes a new combination function to update α. Consequently, the reconstruction results are compared with those of traditional common methods, and the effect of different α update functions is observed on the reconstruction results. The results from the model and real CT images demonstrate that the proposed L1-αL2 + TV method yields superior reconstruction results compared to ART + TV, SART, and L1/L2 algorithms based on objective evaluation indexes such as RMSE, SSIM, and PSNR, the proposed L1-αL2 + TV method achieves SSIM improvement of at least 15.2 %. Moreover, the newly proposed combined function is better at preserving the grain of the image, resulting in a much-improved reconstruction of the contours, making it highly beneficial for subsequent conservation and restoration of heritage. Overall, this proposed L1-αL2 + TV mixture model provides low-noise and high-quality reconstruction results, while maintaining the grain of the original image, making it a great boon for heritage conservation and restoration.

The conservation and utilization of museum relics based on internet of things and fuzzy control

With the development of Internet of Things and fuzzy control theory, there are new opportunities for the conservation and utilization of museum artifacts. The traditional way of heritage restoration lacks the overall harmony of heritage restoration, which leads to the stagnation of heritage restoration level. At the same time, traditional heritage conservation is also limited to manual management, which seriously hinders the development of the overall level of museums. Artifacts are of great commemorative and research value and are objects that have been handed down to mankind for thousands of years and have been subjected to the natural environment for a long time before being excavated. Heritage conservation requires not only restoring artifacts to the greatest extent possible, but also securing the environment in which they are displayed and stored to ensure that they can be preserved for as long as possible. But the following problems exist in the conservation of cultural relics (1) the lack of strict standards for the environment in which cultural relics are stored. (2) the professional competence of the staff is not strong. (3) The lack of a strict management system (4) heritage conservation technology is backward. To solve these problems our team constructed a fuzzy control method based on fuzzy control theory to assist in the restoration of cultural relics. The model constructed by fuzzy control theory solves this problem. The fuzzy control theory constructs a model for restoration of cultural relics, taking into account the overall harmony of the relics and the accuracy of the points, which is of great significance for the restoration of museum relics. At the same time through the Internet of Things technology to build a library heritage protection system, the main content of the system is (1) the use of Internet of Things technology to build a security protection system for cultural relics (2) the use of Internet of Things technology to detect the storage environment of cultural relics (3) the use of Internet of Things technology to optimize the management process of cultural relics (4) the use of Internet of Things technology to achieve real-time monitoring of the flow of information on cultural relics. And based on this, suggestions are made to (1) improve the museum heritage protection and utilization system (2) improve the infrastructure of museum heritage protection and build a good environment for heritage storage (3) improve the quality of heritage managers. The model constructed in the article has been tested in practice and is feasible, with certain practical and theoretical values.

Study and Digital Restoration of Costumes Unearthed from the Tomb of Zhao Boyun

Abstract Ancient costumes are a valuable historical heritage of Chinese civilization, and the preservation of traditional culture is an essential contemporary research topic. However, exhibiting precious cultural relics will risk damage, but digitizing traditional costumes can effectively solve this problem through virtual exhibition, and help traditional costume culture spread more widely with the help of technology. The article took sixteen costumes worn by the owner of the tomb of Zhao Boyun of the Southern Song Dynasty in Huangyan as the object of study, analyzed their structural dimensions and fabric patterns, and digitally restored them using the style3D software system. Finally, the fuzzy analytic hierarchy process evaluated the garment restoration effect. This approach effectively combines the conservation of cultural relics and cultural inheritance with information technology and digitalization, which provides new ideas for disseminating traditional costumes and promotes the heritage and development of ancient Chinese costumes.

Mechanisms of lead-containing pigment discoloration caused by Naumannella cuiyingiana AFT2T isolated from 1500 years tomb wall painting of China

Biodeterioration of ancient wall paintings is a ubiquitous phenomenon that threatens the long-term survival of invaluable cultural heritage. In this study, the Naumannella cuiyingiana AFT2T, isolated from the surface of tomb paintings dating back 1500 years, was observed to be capable of altering the appearing colors of Pb-containing pigments. By a combination of physiological and biochemical measurements and transcriptomic analysis of strain AFT2T under Pb amendment treatments, the discoloration mechanisms were investigated further in depth. Incubation experiments showed that the discoloration reaction resulted from an interaction between Pb-containing pigments and strain AFT2T cells. Subsequently, we found that strain AFT2T had ability to assimilate Pb ions from pigments by using EDX mapping. Finally, after comparing to the controls, it is speculated that the observed discoloration is the formation of cellular product PbS and a series of additional tests were conducted to verify this. In addition, controlling the chemical composition in the culture medium was utilized to confirm the source of S which might be related to the sulfur-containing amino acids of animal proteins in the medium. Transcriptomic analysis exhibited that Pb stress strongly affected the expression of some genes in strain AFT2T, such as metal ion transport and metabolism genes and genes related to the TlpA family protein disulfide reductases. Among them, the gene of the enzyme with disulfide-bond reducing properties and the gene encoding the divalent Pb ion uptake transporter are the key genes in the process of discoloration. A combination of biochemical reactions and transcriptomic analysis was utilized to reveal the key genes involved in the discoloration of Pb-containing pigments by strain AFT2T. These results provide not only new insights and a theoretical basis for the conservation of cultural relics but also a new means for the management of heavy metal pollution in the environments.

RESEARCH ON THE DIGITAL EXHIBITION OF CULTURAL RELICS FOR CROSS-CULTURE COMMUNICATION: CASE STUDY ON CHINA-GREECE COOPERATION ON TERRACOTTA WARRIORS

Abstract. With epidemics blocking offline interactions, it is difficult to organise events such as tours of major heritage sites and outbound exhibitions of cultural relics, and new paths need to be expanded for the presentation of cultural heritage and intercultural education efforts. With the booming development of digital technology, the integration of online virtual presentation and interactive technology and the innovative design of 3D scenes provide new solutions for the intercultural communication of these precious and immovable cultural relics (e.g. archaeological sites), etc. This project is based on the Sino-Greek cooperation around the online presentation of heritage items such as the Terracotta Warriors and Horses of China and the precious collection of the National Archaeological Museum of Greece, in order to present and On the basis of communicating the value of heritage and the connection between Chinese and Greek civilisations, the project explores the development of a virtual space that integrates the Terracotta Warriors and Horses pits, the interactive virtual display of cultural relics, and the display of the achievements of scientific and technological conservation of cultural relics, so as to realise the cross-cultural exchange between China and Greece and fulfil the educational function of heritage.

Evaporation-induced crystal self-assembly (EICSA) of salt drops regulated by trace of polyacrylamide

The anisotropic growth and the different interface properties of ionic crystal at microscale make it difficult to control and obtain the ordered crystals at macroscale, resulting in rare researches on self-assembly of ionic crystal. The method of evaporation-induced crystal self-assembly (EICSA) has been demonstrated for the construction of highly ordered self-assembly configurations in the sodium chloride (NaCl) drops regulated by trace of water-soluble organic polymer (polyacrylamide, PAM) on the hydrophobic substrate. According to the dynamic behaviors of self-assembly configurations, the concentration phase diagram of configurations is given, showing that EICSA is a process from disorder to order with the increase of the amount of PAM. We interpret this phenomenon as a result of the addition of PAM promotes the nucleation and inhibits the growth, producing a large number of NaCl with small size. Meanwhile, the adhesion of PAM makes NaCl orderly assembled together. Particularly, the mechanisms of the spontaneous lifting of crystals are directly revealed through our experiments. Moreover, we develop the lattice model to explain the physical mechanisms behind the evolution of self-assembly configurations. Furthermore, the dependence of the evaporating rate from regions (III) to (I) on the mixing free energy change is found to be consistent with the Arrhenius behavior. Our results have shown a further understanding of construction and control in self-assembly of ionic crystal, which has great applications in protection of outdoor electronics, conservation of cultural relics and chemical production.

Proteomics and Immunology Provide Insight into the Degradation Mechanism of Historic and Artificially Aged Silk.

The process and mechanism of silk degradation is still a bewildering mystery in the investigation and conservation of cultural relics, which rely on the development of accurate and tailored analysis technologies. Here, two advanced approaches, proteomics and immunology, were developed for determining the deterioration behavior of historic silk fabrics and artificially aged samples from the molecular to the holistic level. The surface morphology and secondary structure of silk were destroyed during degradation. Subsequently, the proteomics and immunology analysis demonstrated a new degradation model differing from previous reports. First, the amorphous region and the looser crystalline regions were destroyed together, and the macromolecular chains were broken randomly. Then, the tight β-sheet blocks in the crystalline region were exposed and deteriorated, which expedited the degradation of tight β-sheet blocks and relatively loose blocks in the crystalline domain as well as the amorphous domain, ultimately yielding small molecule polypeptides. However, the deterioration process of ancient fabrics could be accelerated by poor burial conditions, thus showing distinct destructive characteristics. Overall, the results gave us a more comprehensive and profound understanding of the degradation process of ancient silk.

RESEARCH ON NON-DESTRUCTIVE TESTING TECHNOLOGY IN RENOVATING PROJECTS OF MUKDEN PALACE

Abstract. With the increasing emphasis on the conservation of cultural relics, the renovation work of historic buildings has become more and more important. Basically, most of the ancient buildings in China are wooden structure. Wood is a flexible material which could resist deformation in the earthquake. The drawback, however, is that they are susceptible to temperature, humidity and other external influences (which will lead to rot, cracks, tilt, foundation settlement, etc.), and poses a hidden danger to entire architecture. Besides, after years of use, the decline in mechanical properties could affects their bearing capacity. Moreover, traditional renovation methods, determining renovation and demolition in the absence of accurate and effective detection and evaluation methods, like eyeballing, knocking, which are simple and depend largely on manual experience and lacks of accuracy, will cause the loss of historical information of ancient construction. Also, Traditional way of stylobate repairing can only be qualitative analysis which are visually or empirically, deciding partial repair or comprehensive replacement. Internal damage remains unclearly and inaccurately that often result in the loss of historical information and over-repair of heritage. Paper aims to interpret with two typical example in Mukden Palace, where located in the temperate sub-humid continental climate, with a huge temperature difference between day and night, one is the stone stylobate of Dazheng Hall, the palace used for holding ceremonies, the other is the wooden structure of Ancestral Temple. Both faced with varying degrees of damage, such as foundation broken, frieze panel inclined and pillar cracked. Non-destructive Testing (NDT) Technology using in those two projects includes 3D scanning, ground penetrating, concrete ultrasonic testing and mineral element analyzing that can collect data more comprehensive than just using traditional methods, especially for internal damage. Then generating the quantitative analysis of damage category. Furthermore, discussing cause of damage and moderately protection methods of the stone stylobate and the wooden structure on the basis of testing. As well as providing references of repairing project of traditional Chinese stony heritage.

Shaking Table Tests of Dou-gong Brackets on Chinese Traditional Wooden Structure: A Case Study of Tianwang Hall, Luzhi, and Ming Dynasty

Using the Dou-gong brackets on the column of the Tianwang Palace in the Baosheng Temple from the Ming Dynasty as the research object, an experimental study was conducted on 15 groups of shaking table tests of a full-scale Dou-gong specimen made of Douglas fir. Through the analysis of dynamic magnification coefficient trends, the process of displacement characteristics of the Dou-gong in response to changes of vibration, and the rotary and sliding displacement values for each part of the Dou-gong at the largest deformation moments, major conclusions were drawn as follows. A higher vibration excitation intensity input resulted in a stronger damping effect of the Dou-gong model. The maximum deformation of each member had a strong correlation with the maximum deformation of the whole structure, among which the rotary deformation of the Lu-dou and Hua-gong occupied a dominant position. The Hua-gong with Ang, one special part of the Dou-gong, had relatively weak connection nodes during the tests; therefore more attention and relevant reinforcement measures should be taken on this part in the maintenance and conservation of cultural relics.

Deformation Monitoring System Based on 2D-DIC for Cultural Relics Protection in Museum Environment with Low and Varying Illumination

Quantifying the condition of large cultural relics, such as marine archaeological shipwreck, is important to verify stability and reliability. Deformation monitoring system plays a key role in the preservation and long-term conservation of cultural relics. Two-dimensional digital image correlation (2D-DIC) method has proven its efficiency in being able to provide accurate quantitative information of structural deformations. In this study, a deformation monitoring system with four cameras based on 2D-DIC is developed to perform noncontact, optically based measurement to monitor the deformation of shipwreck in museum environment with low and varying illumination. Because the consistency of the accuracy of 2D-DIC measurements for different locations is the most basic requirement in the application of structural deformation monitoring, selecting the appropriate exposure time and quantifying the bias errors on 2D-DIC measurements should be helpful to the optimal use of this optical nondestructive testing technique. A theoretical criterion is deduced to quantitatively characterize the dependence of interpolation bias upon natural patterns and illuminations. Then, an exposure adjustment scheme is built based on the aforementioned criterion. Numerical experiments reveal that the exposure adjustment scheme is able to provide consistency interpolation error for different natural patterns even though the environmental illumination is different as well. The deformation monitoring system with the proposed exposure adjustment scheme is promising for developing flexible and robust in situ structural health monitoring for use in museum environment with low and varying illumination, making 2D-DIC technique a really useful tool for in situ long-term monitoring of large cultural relics.

Preservation of World Heritage and China s World Heritage -Convergence, practice and development of ideology for cultural heritage conservation-

현대적인 의미에서 중국의 문화재 보존 사업은 지난 20세기 50년대부터 시작되었습니다. 1985년에 중국은 세계유산 조약에 가입했고, 1987년에 최초로 세계문화유산을 보유하게 되었습니다. 세계유산 조약과 관련된 내용들과 국제적인 보호이념이 중국에서 널리 인식되고 전파됨에 따라 중국의 세계유산 신청 열의도 지속적으로 상승하였으며, 이와 더불어 <<베네치아 헌장>>을 중심으로 한 보호자료들이 중국의 문화유산 보호 이념과 실천 체계에 중요한 영향을 미쳤고 더 나아가 중국의 전통 문화재 보호 사고방식에도 상호작용을 했습니다. 이에 따라 중국은 국제 문화유산 보호에서 앞장서는 중요한 역할을 하게 되었습니다. 이것은 1987년 이후 30년 동안, 세계문화유산 개념이 중국에 도입된 이후 경험하게 된 중국의 세계문화유산에 대한 인식, 이해와 급속한 발전의 세 단계를 진솔하게 반영한 것입니다. 그와 동시에 전 세계적인 문화유산 보호사업의 발전 맥락에서 봤을 때 중국은 전 세계와 동일하게 유산 보호의 중요한 전환점을 지나고 있으며, 새로운 문제가 제기되면 전문가와 함께 그러한 문제들을 해결하고자 합니다. 어떻게 하면 문화유산이 사회생활에 적극적인 작용을 하고 또한 지속가능한 발전을 실현할 것인가 하는 것이 현재 당면한 가장 중요한 과제입니다.In a modern sense, the conservation of cultural relics in China began in the 1950s. China was party to the World Heritage Convention in 1985 and owned the first batch of World Heritage in 1987. With the further popularization and dissemination of international conservation theories, as well as the growing interest in declaration of World Heritage, documents like The Venice Charter (1964) had great influence in theory and practice of cultural heritage conservation in China, which had an organic interaction with Chinese traditional cultural relics conservation concepts. China is playing an increasingly important role in promoting the conservation of international cultural heritage. This actually reflects the three phases that the concept of World Heritage went through in China in the last thirty years. The three phases were recognition, understanding and rapid development. Meanwhile, in the view of the development pattern of global cultural heritage conservation, China, along with the world, is facing a critical turning point in heritage conservation. New issues have been raised and need to be resolved. Currently, it is an important topic to explore a sustainable way of enabling cultural heritage to play a positive role in social life.

Removal efficiency of an integrated adsorption/photocatalysis system for reducing low concentrations of nitrogen oxides in microenvironments of museums for cultural relics conservation

Nitrogen oxides (NOx) could pose a threat to the conservation of cultural relics and could also enhance the corrosion induced by other pollutants such as sulphur dioxides and organic acids. The NOx removal rate was studied through a combination of adsorption onto bamboo charcoal and photocatalysis. The integrated NOx removal efficiency by both methods was evaluated in both lab and pilot scales. The studies have shown that the direct use of biomass can remove moderate level of NOx; while higher level of NOx removal was achieved by using bamboo charcoal carbonized at 520℃. The photocatalytic oxidation of NOx was found to be well fit with Langmuir–Hinshelwood model. The different carriers of photocatalysis combined with adsorbents were compared, and the optimised process was shown to reduce the nitrogen monoxide and nitrogen dioxide level to 2.76 and 0.68 µg/m3, respectively, in 20% relative humidity (RH). An integrated device was developed, and the results have demonstrated that the combined technologies of photocatalysis and adsorption can have great removal potential for reducing NOx and therefore in improving the air quality under different RH conditions.

Nondestructive testing and assessment of consolidation effects of earthen sites

Earthen sites are widely distributed throughout China, and most of them belong to archaeological sites with significant values, which not only directly witness the origin, formation and development of Chinese civilization, but also possess important values for conservation and exhibition. Many researches and practices on their conservation and consolidation have been carried out; however, the consolidation effect is mainly judged by visual observation and expert evaluation. Scientific assessment of conservation and consolidation effects is a challenging issue. Many instruments in other fields cannot be directly applied to the conservation of cultural relics due to their peculiarity. In order to assess the effects of field conservation experiments, this paper tries to understand the consolidation effects at Liangzhu site using nondestructive or micro-damage methods, including thermo-physical parameters testing, infrared thermal imaging, high-density microelectrode resistivity testing, portable microscope observation, and hydrophilic and hydrophobic testing, and thereby explores the practicable methods for evaluating the properties of consolidation materials for earthen sites treatment.

Digital Technology in the protection of cultural heritage Bao Fan Temple mural digital mapping survey

Abstract. Peng Xi county, Sichuan province, the Bao Fan temple mural digitization survey mapping project: we use three-dimensional laserscanning, multi-baseline definition digital photography, multi-spectral digital image acquisition and other technologies for digital survey mapping. The purpose of this project is to use modern mathematical reconnaissance mapping means to obtain accurate mural shape, color, quality and other data. Combined with field investigation and laboratory analysis results, and based on a comprehensive survey and study, a comprehensive analysis of the historical Bao Fan Temple mural artistic and scientific value was conducted. A study of the mural’s many qualities (structural, material, technique, preservation environment, degradation, etc.) reveal all aspects of the information carried by the Bao Fan Temple mural. From multiple angles (archeology, architecture, surveying, conservation science and other disciplines) an assessment for the Bao Fan Temple mural provides basic data and recommendations for conservation of the mural. In order to achieve the conservation of cultural relics in the Bao Fan Temple mural digitization survey mapping process, we try to apply the advantages of three-dimensional laser scanning equipment. For wall murals this means obtaining three-dimensional scale data from the scan of the building and through the analysis of these data to help determine the overall condition of the settlement as well as the deformation of the wall structure. Survey analysis provides an effective set of conclusions and suggestions for appropriate mural conservation. But before data collection, analysis and research need to first to select the appropriate scanning equipment, set the appropriate scanning accuracy and layout position of stations necessary to determine the scope of required data. We use the fine features of the three-dimensional laser scanning measuring arm to scan the mural surface deformation degradation to reflect the actual state of the mural surface patch model. For the degradation of the surface of the pigment layer, we use the patch model to simulate the scan obtained from an analysis. Statistics calculated relatively objective mural surface area from volume data, providing more accurate quantitative data for the mural conservation, especially, providing a viable technology for accurate monitoring of continued degradation. We believe, in order to make use of the three-dimensional laser scanning technology in a digital heritage conservation application, the technology should not only be used to record the object geometry and play a role in record keeping aspects, but, rather, should be used during the investigation to protect against targeted degradation and a more meaningful interpretation function. Like the development of the medical application of X-ray technology not only retains a picture, but more importantly, through this technical interpretation of patient pathology, guides doctors in carrying out the treatment work. Therefore, in the process of digitization of cultural heritage research, the focus should shift to the use of digital technology in the analysis of heritage object degradation and degradation monitoring surveys can promote the application of digital technology in the conservation of cultural heritage.

An experimental study on application of sticky rice–lime mortar in conservation of the stone tower in the Xiangji Temple

Sticky rice–lime mortar is one of the most important technological inventions in the Chinese architectural history. In this work, an experimental study on the application of sticky rice–lime mortar in conservation of the stone tower in the Xiangji Temple was performed by means of the property characterization, SEM, XRD and DSC-TG analysis. Our Results indicate that paper fiber is the most effective admixture to endure freezing–thawing cycles and increase the compressive strength of sticky rice–lime mortar, and the use of aluminum sulfate reduces the drying shrinkage values and increases the compressive strength because of the formation of ettringite in sticky rice–lime mortar. It is suggested that 6% aluminum sulfate or 3% paper fiber may be the appropriate admixture of sticky rice–lime mortar in conservation of cultural relics. Based on the results of laboratory experiment, the sticky rice–lime mortar with 3% paper fiber is selected as the grouting material for the conservation of the Xiangji Temple tower.

"Saltman" a new archaeological discovery: scientific investigation and conservation

The conservation and scientific investigation of organic materials in general and ancient human remains in particular have always been a topic of immense interest to scholars. The so called “Iceman” is one example which has attracted both general the public and experts worldwide since its discovery in 1991. The discovery of the Saltman in Iran in 1994, in a remarkable condition of preservation, is another example of this. The remains were found in a salt mine located in the village of Hamzehloo, near Zanjan. After the initial investigation by archaeologist, all the finds were transferred to Research Center for Conservation of Cultural Relics for scientific investigation and preservation. All the remains were subjected to Carbon-14 dating, radiographic examinations, computer tomography, texture examinations, genetic research, chemical, biological and physical examinations of the hair, trace element analysis, technological and compositional examinations and lastly conservation of all the remains.