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1.
本研究以细菌纤维素作为纸质档案的加固剂,制备不同质量分数的细菌纤维素水分散液,均匀喷涂在纸张上,对纸张进行加固处理。采用万能材料试验机、耐折度仪、扫描电镜、柔软度仪、光泽度仪、厚度仪、非接触式分光光度仪、pH计和超景深显微镜等,表征细菌纤维素对纸质档案的加固作用;利用TG/DTG热分析仪和红外光谱仪,表征细菌纤维素对纸质档案微观结构的影响。结果表明,质量分数为0.3%的细菌纤维素加固纸张后,纸质档案的机械强度提高最明显,加固纸张的效果最好;细菌纤维素在加固纸张的同时增加了纸张的稳定性,且没有改变纸张的微观结构。  相似文献   

2.
ABSTRACT

The tomb of Tutankhamen in the Valley of the Kings, Egypt, one of the major attractions of the World Heritage Site of Ancient Thebes and its Necropolis on the West Bank of modern day Luxor, is today a destination for mass tourism. Visitors to the tomb increase relative humidity, elevate carbon dioxide levels, and encourage natural ventilation which facilitates entry of dust into the tomb. These conditions negatively impact the wall paintings and remaining artifacts in the tomb and create an uncomfortable environment for visitors. The deposition of dust inside the tomb collects on uneven wall painting surfaces, obscures their legibility and necessitates cycles of cleaning, which in turn leads to further damage. Developing environmental management strategies in the tomb to counter the effects of visitors and mitigate dust entry is an important component of the collaborative project between the Getty Conservation Institute (GCI) and Egypt’s Ministry of Antiquities (MoA) to conserve the tomb. These included implementation of a filtered-air supply and exhaust ventilation system to stabilize the interior microclimate and reduce dust in order to improve visitor comfort and contribute to the long-term preservation of the tomb.  相似文献   

3.
《文物保护研究》2013,58(4):281-297
Abstract

Cellulose poultices are frequently used in stone and wall painting conservation for the purposes of soluble salt extraction, consolidation and cleaning. They have the reputation of being easy and pleasant to work with, have a neutral pH, high water absorption and plasticity, exhibit good conformance and adhesion to the substrate, and in most cases leave minimal residues after clearance. The cellulosic materials from which they are composed range from cotton wool, blotting paper or newspaper, to cellulose powders, the latter now by far the most common form of cellulose used today by conservators. Drawbacks of these products include poor water retention when applied to vertical surfaces, a tendency to redistribute salts further into the object substrate, and poor long-term treatment effectiveness for salt extraction. Hence cellulose poultices are used frequently due to good working properties, but apparently are in some situations not very effective. In this paper, existing knowledge of these poultices is outlined, followed by investigations undertaken to fill some of the knowledge gaps. Investigations include characterization of poultice properties such as pore size distribution and workability, and of moisture transport processes within poultice/substrate systems including moisture penetration depth, moisture distribution, and poultice shrinkage during drying. Cellulose powder products known under the trade name Arbocel®, extensively tested and used in conservation over several decades, were a particular focus. Resulting guidelines include counter-intuitive measures such as (when used for salt extraction purposes) the use of thinner poultices to reduce drying shrinkage and salt redistribution further into the substrate. The relatively uniform pore size distribution (around 10 μm) of Arbocel® poultices makes them more appropriate for salt extraction on substrates with a medium-coarse pore size (i.e. 15 μm and above), while on fine porous substrates (10 μm and below), the extraction will not be as efficient.  相似文献   

4.
ABSTRACT

This paper proposes a new way of interpreting particulate matter deposition indoors. The rate of deposition of dust in surfaces is presented as the result of the combination of two main factors: the concentration of suspended particles close to surfaces, and their capacity to deposit, expressed as the deposition velocity. We suggest that either of these two factors can be altered in order to mitigate deposition. The implications of this perspective are explored using in-situ measurements in a historic property (Apsley House, London) and a computational fluid dynamics model of aerosol deposition. The cases studied involve the effect of outdoor wind on the ingress of particles, the consequences of leaving the main door open, and the effects of the ventilation system on deposition. The results demonstrate that simulations can be used reliably to explore hypothetical scenarios or situations that would be experimentally challenging. The inputs and outputs of the computational model are discussed in view of its usability in preventive conservation.  相似文献   

5.
This paper studies the influence of poultice type and application techniques on the desalination efficiency of two limestone substrates having similar porosities (22–25%) but different pore size distributions: microporous Bateig Novelda and macro porous Tosca Rocafort stones. Three poultice types are compared: pure sepiolite (fine porous), sepiolite and aggregate (medium porous), and pure cellulose powder (coarse porous). Four application techniques are studied: (i) direct application on the stone, (ii) pre-wetting before poultice application, (iii) Japanese paper before application, and (iv) pre-wetting?+?Japanese paper before application. Samples were taken from poultices on the one hand, and from substrates at different depths on the other hand. Their content in soluble salts was estimated by ionic conductivity measurements. After three application runs, the best result for both substrates is achieved with the combined application of coarse- and fine-porous poultices (FPs) (desalination depth: 4.5/6?cm for macro/micro-porous substrates). The FP is also able to extract salts properly, but the desalination depth achieved is less important (3?cm). A direct poultice application without pre-wetting nor Japanese paper is to be preferred for both stone types.  相似文献   

6.
《文物保护研究》2013,58(1):23-29
Abstract

Upon aging, paper documents and books become progressively damaged. Paper deacidification is a fundamental conservation intervention. In this study, we report on the use of nanoparticles of titanium dioxide (TiO2) and magnesium hydroxide (Mg(OH)2) associated with hydroxyethylcellulose (HEC) to inhibit acidification, photo-induced degradation, and biodeterioration of paper. With the aid of ultrasound, Mg(OH)2 nanoparticles with a narrow size distribution can be obtained through homogeneous precipitation in water. Furthermore, to demonstrate the efficacy of the nanocomposite and the performance of treated and untreated paper, photo- and thermal-induced degradation is discussed. The results show that using the controlled double-jet precipitation (CDJP) it is possible to synthesize Mg(OH)2 particles with a narrow size distribution (18–87 nm). The nanocomposite of Mg(OH)2–TiO2–HEC increases the durability of paper by imparting fungal growth resistance (D = 34.6 mm), moderate alkalinity (pH = 8.4), mechanical reinforcement (from 817–896 N/m), and UV protection. Additionally, there is a slight color difference (ΔE* = 0.8) between the treated and untreated paper. Both photodegradation and thermal degradation indicate that the paper treated with this nanocomposite (Mg(OH)2–TiO2–HEC) has increased stability.  相似文献   

7.
《文物保护研究》2013,58(3):199-210
Abstract

Descente des vaches (1836) by Théodore Rousseau in the Mesdag Collection in The Hague is barely readable and its paint layers are in poor condition. The surface of the painting is strongly deformed and cracked, the whole painting has darkened and especially the greens have lost all or most of their colour resulting in brown passages. Large passages of the painting that were painted with multiple thick and medium-rich layers have darkened dramatically. This paper proposes that the degradation of Emerald green (Cu(C2H3O2)2·3Cu(AsO2)2, copperacetoarsenite) – the main green pigment used in this painting – is a significant factor in the cause of the darkening. Electron backscatter images reveal that the Emerald green particles are shown different degrees of degradation: from partially to completely disintegrated. Elemental maps show that arsenic is distributed throughout the paint cross section, with relatively higher concentrations around iron- and aluminium-containing particles, and in the varnish layer. Imaging-Fourier-transform infrared microscopy detects copper soaps in the degraded Emerald green-containing layers. Analytical data from four paint cross sections strongly suggest that Emerald green reacts with free fatty acids derived from the binding medium forming copper soaps and mobile arsenic-based species. Chemical laboratory experiments fully support this hypothesis. Emerald green and palmitic acid in chloroform form copper palmitate and arsenic trioxide (arsenolite, cubic) under room temperature and normal light conditions. The degradation of Emerald green particles in Descente des vaches has resulted in a loss of light-reflecting surfaces and in newly formed compounds in the paint, both contribute to the colour change from green to brown.  相似文献   

8.
目前的档案修裱黏合剂普遍使用纯淀粉浆糊,但纯淀粉浆糊形成的淀粉膜抗拉力弱、脆性大、易断裂,使得修裱后的纸张强度与耐久性不高。针对这一问题,将淀粉浆糊中添加不同比例的碳纤维进行改性,通过检测纯淀粉浆糊与改性淀粉浆糊所修裱的纸张的物理与化学性能,包括耐折度、撕裂度、抗张强度、pH值、白度,对比分析不同比例碳纤维改性淀粉浆糊对档案纸张强度的影响。结果表明,当碳纤维在淀粉中的质量比为1%时,修裱纸张的各项性能得到了显著提升。  相似文献   

9.
This study examined multiple factors associated with the processof public opinion including relevant predispositions, mediause, interpersonal discussion, and perceptions of communityopinion in order to test a theoretical model of public opinion.We conceptualized these factors as intrapersonal, media, andsocial ‘filters’ within the public opinion process.To test the impact of these filters, we conducted a survey withtwo independent samples—the first sample was collectedduring the introduction phase of a community ballot issue andthe second just a week before the issue vote. Findings indicateall three filters impacted public opinion regarding the ballotissue. Within these filters, important subprocesses were analyzedto better understand each filter's contribution to the formationof public opinion. Ordinary least squares (OLS) regression equationsused to test the proposed process model revealed that the intrapersonalfilter accounted for a substantial amount of the overall variancein public opinion, but that media and social filters were alsoimportant predictors. Results highlight the importance of communicationvariables in the formation of public opinion. Received for publication May 4, 2006. Accepted for publication April 19, 2007.  相似文献   

10.
《文物保护研究》2013,58(3):164-171
Abstract

With the aim of developing a new easy-to-use method for rescuing flood-damaged paper, the effect of saltwater on the inhibition of fungal growth on paper was investigated. This procedure could be used instead of, or assisted by freeze drying. Cellulose-digesting Trichoderma reesei, three types of fungi representative of fungi growing on paper (T. reesei, Aspergillus terreus, and Aureobasidium pullulans) and various naturally airborne fungi were cultured on cellulosic materials in liquid media containing artificial seawater with different salt concentrations. The addition of salts successfully inhibited the growth of T. reesei on microcrystalline cellulose at the concentration of 3.2% (m/m) or higher. The critical salt concentration, 3.2%, is within the general range of salt content in seawater. Other solutions of salts similar to sodium chloride also inhibited fungal growth. Although the observed growth-inhibiting effect was attributed to the high osmotic pressure of the salt solution, physiological effects depending on ion species used were also considered to be possible. The growth of all three types of fungi on copy paper was inhibited effectively when the salt concentration was increased. The growth of various fungi on pure cellulose, with enough oxygen supplied to pores, was completely inhibited (as assessed by visual examination) for 24 days at salt concentrations of 3.5% (m/m) or greater. The fact that the effect of saltwater on cellulosic materials was observed even under optimum medium conditions implies that fungi would be considerably inhibited on flood-damaged paper immersed in saltwater. This method is a promising first aid measure when circumstances do not allow for flood-damaged paper to be dried immediately.  相似文献   

11.
纸质文献在长期保存和使用过程中,由于年代久远,环境中灰尘颗粒的覆盖、霉菌滋生、气体侵蚀等因素,泥斑、水渍、霉斑、油斑等在所难免。有些污渍会污染纸张,附着于纸张表面或渗透到纤维内部,影响纸张寿命;有些遮盖字迹影响阅读。清洗纸质文献的就显得尤为重要,是修复工作中非常重要的一项内容,是修补、托裱等修复工作的前期工作。中国自古至今所使用的清洁方法比较单一,水洗是常用的方法。本文针对国内外近些年来清洁技术、设备的研究、发展及其应用,在分析对比各类清洁方法的基础上,针对不同的污染物类型介绍具有实操性的技术与方法,以便于指导实际工作,填补我国清洁设备与技术的空白。  相似文献   

12.
ABSTRACT

Research into dust deposition rates on the wall paintings in the State Apartments at the Palace of Westminster, London, UK, began during the restoration of the encaustic floor tiles. The study has broadened to inform day-to-day preventive care for the extensive fine art collections on display and the intricately decorated Gothic interiors, providing a powerful tool for the forthcoming restoration and renewal of the Palace. Different monitoring methods, using optical microscopy, macro-photography and software-based image analysis, were investigated. Qualitative analysis with SEM-EDX and optical microscopy allowed the identification of a number of anthropogenic, geogenic and biological sources of particulate matter, while quantitative results elucidated deposition trends, highlighting both seasonal and works-related impacts. Results indicated that mitigation measures taken to protect works of art and limit the diffusion and deposition of particulate matter on surrounding surfaces were successful. A new dust monitoring method, based on imaging of vertical surfaces and on a recently developed image analysis workflow (CHIJ) operated in open-source software (ImageJ) was trialled alongside more traditional methods for measuring dust deposition through collection of particulate matter on proxies. Results showed significant discrepancies between data acquired directly on wall painting surfaces as compared to horizontal glass slides. The advantages, limitations and complementarity of both monitoring methods were identified, and their potential contributions to the development of data-driven conservation approaches for heritage sites were assessed. The relatively low-tech methods and equipment used present useful and adapted tools for collection managers and conservators to inform their decision-making processes.  相似文献   

13.
The conservation of wooden objects is complicated by their response to changes in their environment. In particular, filling voids in wooden objects can be difficult when their dimensions might be expected to alter over time. A short survey of conservators showed that a wide variety of materials have been, and are being used for this purpose. Following conservation work undertaken on a wooden coffin, the author wished to investigate the properties of cellulosic materials and their suitability in the conservation of wooden objects. This paper shares the results of experiments that were conducted to determine the way in which hydroxypropyl cellulose (HPC) and paper pulp fills respond in various conditions, as compared to other fill materials used by conservators. The compatibility of the HPC and paper pulp fills with wood is satisfactory enough to be able to recommend their use in the conservation of wooden artefacts, but ideally further experiments would be carried out, and on a wider variety of fill materials.  相似文献   

14.
在海量信息中检索时,与用户查询相关的信息常常被漏掉,而与查询无关的信息———信息垃圾,却大量地出现在检索结果中。改进文本信息检索系统的质量,提高检索效能,已成为亟待解决的问题。本文针对能够影响检索效力的一个易被忽略的因素———修饰语,研究其在文本信息检索中的作用。为此,构建了修正的向量空间模型(Modified Vector Space Model,MVSM),并以英文文本进行试验,进而说明修饰语的作用。  相似文献   

15.
none 《文物保护研究》2013,58(4):253-266
Abstract

The use of sodium nitrite (NaNO2) as a corrosion inhibitor for wet archeological metal objects presents potential advantages of near neutral pH, low concentration, effectiveness on several metals, and compatibility with organic materials. The effectiveness of NaNO2 as a corrosion inhibitor for storage of chloride-containing marine archeological metal objects from the wreck of the USS Monitor was evaluated using marine-corroded carbon steel analogs. The samples were tested in varying concentrations of NaNO2 and evaluated visually and by monitoring solution chemistry using ion chromatography (IC). It was found that a concentration of 1000 ppm NaNO2, replaced four times, was effective at protecting corroded carbon steel in the presence of chlorides. Nitrite solutions were no more rapid than sodium hydroxide (NaOH) at extracting chlorides from marine steel at equal concentrations and were considerably slower than 2% NaOH. IC analyses indicated that NO2 does not easily oxidize to NO3 under normal conditions, but does so readily when a polarizing current is applied, making nitrites unsuitable for electrolytic reduction treatments. Sodium nitrite does show promise as a storage solution prior to desalination of marine metals or after desalination to prevent flash corrosion during rinsing baths.  相似文献   

16.
Searching for health information is a core activity for health library and knowledge workers, whether seeking to support health care workers in overcoming barriers to accessing drug information, exploring the potential of text mining in developing search filters, translating search filters for use on alternative databases, or the importance of updating search filters to ensure their ongoing utility.  相似文献   

17.
The webbing clothes moth Tineola bisselliella (Hummel, 1823) is one of the most common museum pests and can be found all over the world. The larvae damages objects made of feather, wool, fur, and other keratinaceous materials. Pheromone traps are important tools in integrated pest management, which allow the detection of infestations and evaluation of their extent. Organic-rich dust (detritus) or other materials of animal origin, such as dead birds, can be an alternative food source for the moths. This paper analyzes monitoring data collected with pheromone traps from six different museums in Vienna and Berlin and tries to differentiate between moths resulting from infested objects or moths coming from other food sources, such as organic-rich dust. Annual totals of moths trapped and catch rate (moths per trap) are important guides for selecting appropriate remedial measures. Long-term data (over six years) enabled us to interpret monitoring results and differentiate between active infestation of objects and cleaning or housekeeping problems. However, detailed knowledge of the site and buildings, availability of high-quality food for the larvae, and lack of regular cleaning are also important factors to consider when interpreting the data.  相似文献   

18.
Objective:There are no existing validated search filters for the group of 37 Organisation for Economic Co-operation and Development (OECD) countries. This study describes how information specialists from the United Kingdom''s National Institute for Health and Care Excellence (NICE) developed and evaluated novel OECD countries’ geographic search filters for MEDLINE and Embase (Ovid) to improve literature search effectiveness for evidence about OECD countries.Methods:We created the draft filters using an alternative approach to standard filter construction. They are composed entirely of geographic subject headings and are designed to retain OECD country evidence by excluding non-OECD country evidence using the NOT Boolean operator. To evaluate the draft filters’ effectiveness, we used MEDLINE and Embase literature searches for three NICE guidelines that retrieved >5,000 search results. A 10% sample of the excluded references was screened to check that OECD country evidence was not inadvertently excluded.Results:The draft MEDLINE filter reduced results for each NICE guideline by 9.5% to 12.9%. In Embase, search results were reduced by 10.7% to 14%. Of the sample references, 7 of 910 (0.8%) were excluded inadvertently. These references were from a guideline about looked-after minors that concerns both OECD and non-OECD countries.Conclusion:The draft filters look promising—they reduced search result volumes while retaining most OECD country evidence from MEDLINE and Embase. However, we advise caution when using them in topics about both non-OECD and OECD countries. We have created final versions of the search filters and will validate them in a future study.  相似文献   

19.
薛翔宇  张涛 《大观周刊》2012,(36):43-43
沙尘暴主要是春季发生的危害我国及东亚地区的灾害性天气现象。这些颗粒主要来自于经过传统方法翻耕、土壤表面缺少覆盖物的农田或退化的草原。防御沙尘暴的主要措施是在裸露的农田上实行作物残茬覆盖;在退化的草原上种植牧草;建立防风屏障等。  相似文献   

20.
ABSTRACT

Sandstone is a common sedimentary rock that is easily carved due to its weakly cemented fine grains and relatively low strength. Therefore, numerous large-scale grottoes in China are made of sandstone. However, these sandstone cultural heritage structures are often seriously damaged due to temperature and humidity changes, air pollution, biodeterioration, and repeated dissolution and crystallization of soluble salts. In general, it is imperative that a consolidant capable of providing cohesion by infilling pores between the stone grains is synthesized. In recent years, it has been reported that using organic consolidation materials for sandstone protection comes with various negative effects, such as a short lifetime, poor compatibility, and preservation damage. Using inorganic consolidation materials to protect sandstone seems to be one of the research trends for the future. Herein, this paper introduces a permeable, inorganic magnesium-based material (MMH solution) for silica sand consolidation. To assess this consolidant, the paper investigates the influence of varying molar ratios of MgO:MgCl2·6H2O:H2O on properties such as penetration depth, consolidation weight, colour variation, and compressive strength. The results demonstrate that the molar ratios of MgO:MgCl2·6H2O:H2O can significantly affect the consolidation performance. Additionally, it is believed that the MMH solution of MgO:MgCl2·6H2O:H2O?=?5:1:16 can be successfully used for the consolidation of silica sand, as the cubic specimens’ surface micrographs show good compatibility between the consolidation product and sand grains. Experiments (i.e. weight loss rate and mineralogical compositions analysis) are performed to evaluate the cubic specimens’ water resistance properties after being immersed in water. Furthermore, the consolidation material’s failure mechanism as a self-sacrificing material is preliminarily analyzed. Results indicate that MMH solution is a promising conservation material that shows great potential for consolidating severely weathered sandstone.  相似文献   

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