饱水木质文物的风冷干燥脱水研究

许多出土饱水木质文物因其降解严重、含水率较高,容易在脱水过程中出现不可逆的收缩变形以及开裂现象,从而遭到严重破坏。因此,饱水木质文物脱水方法的研究是文物保护工作中的重要课题。为探究风冷冷冻法对饱水木质文物脱水的效果,以一批无法复原的出土饱水木质文物为研究对象,在对其材种、含水率、基本密度及化学成分进行了测定和分析后,使用一台风冷电冰箱在-18℃条件下对样品进行了风冷干燥脱水处理,记录脱水时间和脱水效果,并分析了该方法的传质传热特点,证明了风冷干燥法用于饱水木质文物的脱水干燥能够取得良好效果,并且具有对文物干预小、适用性广、操作简便、成本低廉等优点,为饱水木质文物的脱水处理提供了一种新的思路。     

Capillary Active Interior Insulation Systems for Wall Retrofitting: A More Nuanced Story

To thermally upgrade exterior masonry walls, interior insulation is often the only possible retrofitting technique, especially when dealing with historic buildings. Unfortunately, it is also the riskiest post-insulation technique, as frost damage, interstitial condensation, and other damage patterns might be induced. To diminish those risks, nowadays so-called capillary active interior insulation systems are often promoted. These systems aim a minimal reduction of the inward drying potential, while interstitial condensation is buffered.

Currently, several capillary active systems are on sale. These different types have, however, widely varying properties. In this article, a closer look at the hygrothermal properties and the working principle of a number of “capillary active” interior insulation systems is made. The spread in capillary absorption coefficients and the vapor diffusion resistances of the different systems is discussed and their influence is illustrated. Based on all this, a more nuanced view on capillary active insulation systems is pursued.

Abbreviations: AC: aerated concrete; CaSi: calcium silicate; GM: glue mortar; GB: gypsum board; HAMFEM: Heat Air and Moisture Finite Element Method; MW: mineral wool; PE: polyethylene; PIR: polyisocyanurate; PUR: polyurethane; VIP: vacuum insulation panel; WFB: wood fiber board; XPS: extruded polystyrene; sd_dry: dry vapor diffusion resistance factor; µ_dry: dry vapor diffusion resistance     

Energy use by Eem Neanderthals

An analysis of energy use by Neanderthals in Northern Europe during the mild Eem interglacial period is carried out with consideration of the metabolic energy production required for compensating energy losses during sleep, at daily settlement activities and during hunting expeditions, including transport of food from slain animals back to the settlement. Additional energy sources for heat, security and cooking are derived from fireplaces in the open or within shelters such as caves or huts. The analysis leads to insights not available from archaeological findings that are mostly limited to durable items such as those made of stone: Even during the benign Eem period, Neanderthals faced a considerable heat-loss problem. Wearing tailored clothes or some similar measure was necessary for survival. An animal skin across the shoulder would not have sufficed to survive even average cold winter temperatures and body cooling by convection caused by wind. Clothes and particularly footwear had to be sewn together tightly in order to prevent intrusion of water or snow. The analysis of hunting activity evolvement in real time further shows that during summer warmth, transport of meat back to the base settlement would not be possible without some technique to avoid that the meat rots. The only likely technique is meat drying at the killing site, which indicates further skills in Neanderthal societies that have not been identified by other routes of investigation.     

青海汉代漆奁的脱水报告

采用聚乙二醇滴渗喷涂、真空冷冻干燥等浸饱水漆木器的脱水处理方法,对北方干燥地区槽朽漆木器进行了脱水保存。处理后器物尺寸稳定,色泽良好,保持了原貌。     

书画装裱材料——宣纸形稳定性的研究

为了加强纸质物的保护,对书画装裱材料宣纸的湿形稳性变化规律进行了研究。通过对不同条件下干燥方法对宣纸形变影响的研究,对纸张变形的原因进行了探讨。实验结果表明,宣纸具有随湿度变形的特性,变形程度与纸的纤维组成和干燥方法有关。采用梯度干燥的方式纸张的尺寸稳定性没有明显的改善。厚度和收缩率相关分析说明二不存在相关性。随着纸张干湿交替处理次数的增多,其变形性趋于减小。为提高纸张的形稳性,可预先进行处理。     

上海元代水闸遗址出土木构件无损冻干初探

传统的冷冻脱水过程通常需要将电阻温度传感器(RTD)插入到物料中以监测温度变化从而确定干燥终点,这种方式对于处理木质文物来说具有一定的破坏性,无法做到无损或微损。本研究尝试采用无损方式对定型加固剂浸渍液即时浓度进行分析,并对冷冻干燥终点进行预测。采用这种无损技术成功地对志丹苑元代水闸遗址出土的30件木构件进行真空冷冻脱水定型处理,既达到了预期的定型保护效果,又确保了木构件的安全。     

Post-Roman crop production and processing: Archaeological evidence from Goldthorpe,South Yorkshire

The remains of a ditched field system dating from the late Iron Age to the early post-Roman period, and two associated corn drying ovens (dating to the 5th–6th centuries AD) were revealed during archaeological excavations at Goldthorpe, South Yorkshire. The site was excavated during 2012 and 2013, during which bulk environmental samples were taken in order to retrieve any surviving botanical remains from deposits associated with the corn drying ovens, and other features across the excavated area. Early post-Roman occupation is under-represented in the archaeological record, especially in northern England, as such human activity and subsistence during this period are currently not well understood. This paper combines evidence for the field system, the physical remains of the corn drying ovens and their associated botanical remains to further understand early post-Roman change and continuity in landscape use and crop production and processing practices.     

出土、出水饱水木质文物冷冻干燥研究进展

冷冻干燥是稳定出土、出水饱水木质文物的主要方法之一。该方法基于水由固态直接成为气态的升华过程不产生表面张力的原理,可避免饱水木材脱水时受到干燥应力的破坏。数十年来,经过实验实践和不断完善,冷冻干燥在出土、出水降解木材的稳定中取得了很好的效果,在大型、厚重木质文物的保护方面得到成功应用。本研究基于在出土、出水含盐饱水木质文物保护方面的多年实践,对国内外在脱盐、抗菌、热浸、预冻和升华干燥工艺等方面的进展进行了回顾,并提出了解决一些现有问题的技术设想。     

Soluble Salts Amplify the Effect of Small Heterogeneities in the Structure of Porous Building Materials During Drying

Salt crystallization is a major cause of degradation in old buildings. One of the issues that stills need clarification is regarding the influence of the salts on the capillary absorption and subsequent drying of porous building materials. This article presents an experimental study that included capillary absorption and evaporative drying tests on two types of material (lime mortar and ceramic brick) using pure water or saturated solutions of six salts (sodium chloride, sodium sulfate, sodium nitrate, sodium carbonate, potassium nitrate, or potassium carbonate). The results of capillary absorption agree only roughly with the linear relationship, predicted by theory, between sorptivity and the square root of the ratio between viscosity η and surface tension σ of the solution (σ/η)^1/2. This poor agreement is probably due to material heterogeneity. The drying dynamics was regular and showed little dispersion between specimens, but only for the uncontaminated materials. Indeed, the drying dynamics of the salt contaminated materials was often irregular or diverged among similar specimens, and the same happened with their salt decay patterns. The main conclusion is that soluble salts can amplify the effects on drying of the small structural heterogeneities that porous building materials normally depict.     

古建筑木结构的保护问题

我国古建筑以木结构体系为主,主要承重材料是木材。木材是生物体,由有机物组成,容易发生腐朽、虫蛀、火灾和力学性能衰减等劣化,其中腐朽和虫蛀等生物危害的发生最为普遍。本文重点介绍了古建筑修缮和保护中,木材的保存、干燥、木材防腐处理的通用药剂和使用方法,针对古建筑保护中存在的树种选择困难、木材防腐处理质量和木材含水率过高等问题,提出建议,为古建筑木结构的保护和维修提供最新的信息。