银纳米薄膜试片在博物馆藏展材料评估筛选中的应用

Oddy测试法是一种最为常用的评估材料是否适合博物馆文物储藏与展示的测试方法,其缺点在于采用活性低的块状金属试片,需要28天的测试周期,同时试片表面平整度以及人为主观因素会影响目测结果的准确性.本工作制备了银纳米薄膜试片替代Oddy测试法中块状金属试片,以半径10mm玻璃圆片为基质,银薄膜厚度约为200～220nm.实验结果表明,采用银纳米薄膜试片后,腐蚀现象在14d后可充分显现并分化,延长至28d时腐蚀现象基本无大变化,有效的缩短了测试周期.同时尝试结合数码图像采集技术,有利于进一步的腐蚀现象数据化分析研究工作,从而得到更加客观准确的测试结果.     

清代淮河流域旱涝灾害的人为因素分析

本文根据历史文献的记载,对清代淮河流域的水旱灾害进行了量化分析,得出了此时期旱涝灾害发生的基本情况。淮河流域的旱涝灾害有的是纯自然力所为,但更多的是人们利用自然的失当所致。本文主要从人为活动因素即人类的不当行为入手,对清代淮河流域旱涝灾害发生的原因作一初步考察。     

Post‐CO2 injection alteration of the pore network and intrinsic permeability tensor for a Permo‐Triassic sandstone

The aim of this study was to determine the process–structure–property relationships between the pre‐ and post‐CO₂ injection pore network geometry and the intrinsic permeability tensor for samples of core from low‐permeability Lower Triassic Sherwood Sandstone, UK. Samples were characterised using SEM‐EDS, XRD, MIP, XRCT and a triaxial permeability cell both before and after a three‐month continuous‐flow experiment using acidic CO₂‐rich saline fluid. The change in flow properties was compared to those predicted by pore‐scale numerical modelling using an implicit finite volume solution to the Navier–Stokes equations. Mass loss and increased secondary porosity appeared to occur primarily due to dissolution of intergranular cements and K‐feldspar grains, with some associated loss of clay, carbonate and mudstone clasts. This resulted in a bulk porosity increase from 18 to 25% and caused a reduction in mean diameter of mineral grains with an increase in apparent pore wall roughness, where the fractal dimension, D_f, increased from 1.68 to 1.84. All significant dissolution mass loss occurred in pores above c. 100 μm mean diameter. Relative dilation of post‐treatment pore area appeared to increase in relation to initial pore area, suggesting that the rate of dissolution mass loss had a positive relationship with fluid flow velocity; that is, critical flow pathways are preferentially widened. Variation in packing density within sedimentary planes (occurring at cm‐scale along the ‐z plane) caused the intrinsic permeability tensor to vary by more than a factor of ten. The bulk permeability tensor is anisotropic having almost equal value in ‐z and ‐y planes but with a 68% higher value in the ‐x plane (parallel to sedimentary bedding planes) for the pretreated sample, reducing to only 30% higher for the post‐treated sample. The intrinsic permeability of the post‐treatment sample increased by one order of magnitude and showed very close agreement between the modelled and experimental results.     

Analysis of the Effect of Provisional Ties on the Construction and Current Deformation of Mallorca Cathedral

This article presents the analysis of the structure of Mallorca Cathedral taking into account the influence on the structural behavior of auxiliary iron ties used during the construction process. Recent studies (Roca et al. 2012, 2013) presented some hypotheses about the construction process of the cathedral. This article complements the previous results by considering the use of auxiliary ties as temporary stabilizing device during the construction. Evidence of the use of ties during the construction has been recognized after a comprehensive survey. The study of the role of such ties and the effect of their later removal are studied by a FE analysis carried out on a representative bay of the structure. The study includes a time-dependent FE analysis after the removal of the ties to assess the long-term structural behavior. The results of the numerical analysis are compared with the deformation trends identified by means of a recent monitoring campaign.     

Wettability alteration of caprock minerals by carbon dioxide

One of the critical factors that control the efficiency of CO₂ geological storage process in aquifers and hydrocarbon reservoirs is the capillary‐sealing potential of the caprock. This potential can be expressed in terms of the maximum reservoir overpressure that the brine‐saturated caprock can sustain, i.e. of the CO₂ capillary entry pressure. It is controlled by the brine/CO₂ interfacial tension, the water‐wettability of caprock minerals, and the pore size distribution within the caprock. By means of contact angle measurements, experimental evidence was obtained showing that the water‐wettability of mica and quartz is altered in the presence of CO₂ under pressures typical of geological storage conditions. The alteration is more pronounced in the case of mica. Both minerals are representative of shaly caprocks and are strongly water‐wet in the presence of hydrocarbons. A careful analysis of the available literature data on breakthrough pressure measurements in caprock samples confirms the existence of a wettability alteration by dense CO₂, both in shaly and in evaporitic caprocks. The consequences of this effect on the maximum CO₂ storage pressure and on CO₂ storage capacity in the underground reservoir are discussed. For hydrocarbon reservoirs that were initially close to capillary leakage, the maximum allowable CO₂ storage pressure is only a fraction of the initial reservoir pressure.     

Dwelling(s) in a north‐west Arabian oasis: decoding residential architecture at Taymāʾ

The definition of an ancient, autochthonous north‐west Arabian residential architecture is still a major void in the archaeology of the region. This preliminary case study is intended to shed some light on this “blind spot” by presenting and analysing the architectural complex E‐b9 from Taymā? (c. fourth/third century BCE until the first/early second century CE). A meticulous study of the architecture identified a modular concept as a key to understanding the complex. Furthermore, underlying patterns of household organisation can be deduced from the architectural remains resulting in the definition of potential household units. Those are indicated by a set of activity areas which are congruent with patterns of accessibility and the use of specific wall types. These findings provide insights into the organisation of households and daily life in the oasis of Taymā?, and may help to define local or regional traditions in the future.     

Temporary consolidation and packaging of fragile cultural relics at underwater archaeological sites to maintain their original state during extraction

The flexible sponge/epoxy composite can wrap underwater artefacts in any shape and forms a protective shell after curing, thus effectively wrapping and reinforcing the artefacts. However, the hydroscopicity of the sponge itself limits the underwater application of the sponge/epoxy composite. In this study, a novel polyurethane sponge was prepared by modified with super-hydrophobic multi-wall carbon nanotubes (SH-MWCNTs@PU sponge). Compared with the pristine PU sponge, the water-contact angle on the surface of SH-MWCNTs@PU sponges increased from 103.3 ± 1.82 to 152.6 ± 1.54^o, and oily epoxy resin was able to cover the surface completely. The study shows that when SH-MWCNTs@PU sponges/epoxy resin composite material is used underwater, it prevents both water from entering the sponge and also the inside epoxy resin from overflowing into the water. Moreover, the composite materials have excellent toughness after reinforcement under water (flexural strength = 3.56 MPa) and the soft sponges can be moulded to wrap any type of underwater artefacts. In the laboratory, when taking a broken, three-dimensional blue-and-white porcelain pot as a research subject, the entire retrieval process—temporary stabilization, packaging, extraction and reinforcement material removal—was simulated to evaluate systematically all the technological aspects of safely excavating fragile underwater relics.     

Post-flood assessment of emergency evacuation policies in the Red River basin, Southern Manitoba

A discrete choice experiment (DCE) was used as a part of a post‐flood survey among the residents of four small urban communities on the Red River ‐ Emerson, Morris, Ste. Agathe, and St. Adolphe ‐ to assess their preferences for emergency evacuation policies. The respondents were asked to choose repeatedly among three hypothetical evacuation policies described in terms of (a) the type of evacuation (mandatory, voluntary, no evacuation), (b) notification time for evacuation (1, 2, 4 days), (c) post‐evacuation flood relief (75%, 80% current, 90%), and (d) an overall evaluation of the risk of hazardous flooding, i.e. chances of over‐dike flooding or breaching through dikes (99%, 75%, and 50%). The survey results indicated that, despite significant differences between Ste. Agathe and other communities in the magnitude of impact of the 1997 flood, overall, a voluntary evacuation seemed to be preferred at the 50 percent risk of hazardous flooding; whereas the preference for a mandatory evacuation was related to a 99 percent risk. A notification time of 2 days for evacuation was preferred over that of 1 day but the preference for 2 days was not statistically different from that of 4 days. In both types of evacuation a 10 percent increase in the amount of flood relief was preferred over the current amount of 80 percent and the marginal utility of a 5 percent decrease was nearly equivalent to the suggested 10 percent increase. Because of such ability of the DCE to assess tradeoffs of alternative choices/policies, the paper suggests further applications of the model for eliciting floodplain residents' preferences for various flood management issues. Dans le cadre d'une enquête effectuée auprès des résidents de quatre petites communautés urbaines ‐ Emerson, Morris, Ste‐Agathe et St‐Adolphe ‐ à la suite des inondations de la rivière Rouge, les préférences du public quant à la politique à suivre en cas d'évacuation ont étéétudiées. L'évaluation a été menée à partir d'un modèle à choix discret. Les personnes interrogées devaient choisir entre trois hypothèses d'évacuation, hypothèses établies sur les bases suivantes: a) le type d'évacuation (obligatoire; volontaire; non‐évacuation); b) le délai accordé avant l'évacuation (1, 2 ou 4 jours); c) les secours procurés à la suite de l'évacuation (75%, les 80% actuels, 90%); et, d) une évaluation d'ensemble des dangers d'inondation, par exemple, les possibilités qu'une digue soit submergée, ou que les digues rompent par endroits (99%, 75% et 50%). Les résultats de l'enquête montrent que, dans l'ensemble, malgré une différence significative dans l'importance de l'impact de l'inondation de 1997 à Sainte‐Agathe et dans les autres communautés, le choix d'une évacuation volontaire était préféré quand ne se présentait qu'une possibilité d'inondation de 50 pour cent; la préférence pour une évacuation obligatoire n'étant indiquée que dans le cas de 99 pour cent de risques d'inondation. Un avertissement avant évacuation de 2 plutôt qu'l jour était préféré par les personnes interrogées, mais, statistiquement parlant, il n'y avait pas de différence notable entre un choix de 2 ou de 4 jours. Dans les deux types d'évacuation proposés, on préférait une augmentation de 10 pour cent des secours par rapport aux 80 pour cent actuels, l'utilité marginale d'une baisse de 5 pour cent étant presque équivalente aux 10 pour cent d'augmentation suggérés. En raison des possibilités qu'offre un modèle à choix discret pour évaluer les compromis possibles entre les différents choix et politiques d'évacuation proposés, cet article suggère que d'autres études à partir d'un tel modèle soient menées afin d'établir les préférences de ceux qui résident dans des plaines susceptibles d'inondation quant à la prévention et à la gestion de ces inondations.     

图象处理方法在研究薄膜试片腐蚀特性中的应用

薄膜试片测试法是一种能够全面有效地对博物馆藏展材料进行评估筛选的测试方法,对其腐蚀现象进行图象采集及进行数据化分析能够得到更为客观准确的测试结果.本工作对应该测试法设计了专门图像采集的硬件装置,采用密闭光源和彩色工业摄像机,可以得到清晰的试片图像.软件系统将采集图像、打开原始图像、图像分割处理、材料分级评价等功能模块化,并根据具体功能设计实现了基本应用的可视化界面.实验表明,该系统能够快速、准确地对藏展材料对试片的腐蚀现象进行数据化分析,使藏展材料的评估分级由人工目测走向计算机视觉计算,具有快速、客观、误差小等特点.     

丙烯酸树脂B72丙酮溶液在陶瓷文物修复中应用比例研究

作为加固剂和封护剂,丙烯酸树脂B72(简称B72)是国内外应用极其广泛的文物保护修复材料,但作为黏接剂在陶瓷修复粘接、补全、涂层饰色流程中的应用比例及范围几乎未见相关研究实例。文章梳理了B72材料性能和配制方式,通过不同比例B72丙酮溶液固化及作业时间和应用状态实验,提出其作为黏接剂在陶瓷文物粘接、补全、涂层饰色修复流程中的应用比例标准、适用范围和配方比例。研究结果可为文物保护者提供B72简便高效的应用甄选方案。