中国古文献中所看到的古代建筑结构力学认识研究

考察古代人的结构力学认识,是对古建筑结构的分析及解释必不可少的研究之一。因为与现代建筑结构不同,古代建筑结构主要取决于当时工匠们的经验与直观判断。古代人对结构力学的认识概念,我们从中国古文献中可以看到。通过本研究发现,古代人已经有对力与荷重的力学认识以及古建筑的对称结构就是从古代力学的平衡概念出发而发展的。     

甲基三甲氧基硅烷对砂岩石刻封护性能的实验室研究

为了解砂岩石刻用甲基三甲氧基硅烷材料封护处理后的各项性能,选择四川省内风化较严重的摩崖造像区的砂岩作为实验样品,采用浸水、酸雾、盐老化、光老化、循环破坏等方法对材料的憎水性、透气性、耐老化性能进行实验测试。试验表明,砂岩样品用甲基三甲氧基硅烷封护处理后其憎水性、耐老化性都有较大的提高,透气性没有太大的改变,半涂样品经循环破坏处理后,表面出现开裂现象。通过研究表明,甲基三甲氧基硅烷材料处理砂岩后其憎水性和耐老化性都较好,但循环破坏实验提示,甲基三甲氧基硅烷材料处理石刻可能对其表面产生负作用,在石刻保护中应慎重使用。     

Koan amphorae from Halasarna – investigations in a Hellenistic amphora production centre

Ceramic amphorae have been the most popular transport and storage containers for a large variety of liquid and solid products. The amphorae of the present study were used as transport containers for wine from the island of Kos (East Aegean). Therefore, they had to fulfil certain requirements in terms of mechanical strength and toughness but also in terms of standardization of vessel size and shape. An assemblage of amphora fragments from the excavation of ancient Halasarna, an amphora production centre, will be presented. The ceramics were studied by means of their chemical and mineralogical composition and fabric. Furthermore, their material properties were measured and their mechanical performance was simulated in computer models.     

Equations of state for basin geofluids: algorithm review and intercomparison for brines

Physical properties of formation waters in sedimentary basins can vary by more than 25% for density and by one order of magnitude for viscosity. Density differences may enhance or retard flow driven by other mechanisms and can initiate buoyancy‐driven flow. For a given driving force, the flow rate and injectivity depend on viscosity and permeability. Thus, variations in the density and viscosity of formation waters may have or had a significant effect on the flow pattern in a sedimentary basin, with consequences for various basin processes. Therefore, it is critical to correctly estimate water properties at formation conditions for proper representation and interpretation of present flow systems, and for numerical simulations of basin evolution, hydrocarbon migration, ore genesis, and fate of injected fluids in sedimentary basins. Algorithms published over the years to calculate water density and viscosity as a function of temperature, pressure and salinity are based on empirical fitting of laboratory‐measured properties of predominantly NaCl solutions, but also field brines. A review and comparison of various algorithms are presented here, both in terms of applicability range and estimates of density and viscosity. The paucity of measured formation‐water properties at in situ conditions hinders a definitive conclusion regarding the validity of any of these algorithms. However, the comparison indicates the versatility of the various algorithms in various ranges of conditions found in sedimentary basins. The applicability of these algorithms to the density of formation waters in the Alberta Basin is also examined using a high‐quality database of 4854 water analyses. Consideration is also given to the percentage of cations that are heavier than Na in the waters.     

Characterization of lime mortar additivated with crystallization modifiers

Additivating mortars with crystallization modifiers is a novel approach to mitigate salt crystallization damage in historic masonry. Once verified the effectiveness of crystallization modifiers in bulk solution, the next step consists in verifying whether: (i) modifiers are still effective when mixed in mortar and going through the carbonation process and (ii) modifiers alter any mortar properties which might limit their application. This research addresses these issues for sodium ferrocyanide and borax, modifiers for sodium chloride, and sodium sulfate, respectively. Several experimental techniques have been applied to elucidate these questions. The results show that the selected modifiers are still able to alter the salt crystallization after going through the carbonation process of the mortar. Besides, no major effects of the modifiers on the fresh and hardened mortar properties were observed. It can therefore be concluded that there are no restraints for the future use of these crystallization modifiers in restoration mortars.     

烧制温度对红砖物理力学性质的影响

在多年自然营力作用下,有些古建筑的砖体正遭受着严重的风化破坏,亟需修复和加固。为此,通过试验,研究烧制温度对红砖物理力学性质的影响,以期为古建筑修复和保护提供理论参考。利用模具手工制作边长为5 cm的立方体黏土砖。利用高温炉分别在700、800、900、1 000和1 100℃的温度下烧制成红砖。然后,测试不同烧制温度下红砖的块体密度、颗粒密度、开孔孔隙率、总孔隙率、常压吸水率、饱和吸水率、毛细吸水系数、纵波波速、孔径分布、单轴抗压强度。结果表明,烧制温度会影响物理力学性质,但物理力学性质并非随着烧制温度的增加而改善。烧制温度为1 100℃时砖的性能最优,烧制温度为800℃和900℃时砖的性能中等,烧制温度为700℃和1 000℃时砖的性能差。本文分析了烧制温度为1 000℃时红砖的物理力学性质差的原因。研究结果可为古建筑修复和保护提供理论参考。     

Material Choices for Fibre in the Neolithic: An Approach through the Measurement of Mechanical Properties

Studies of the Mesolithic–Neolithic transition in Europe have focused on plants and animals exploited for food. However, the exploitation of plants for fibres underwent a significant change with the addition of domestic flax as a fibre crop. While the technology of flax fibre processing is increasingly understood by archaeologists, its material value as a fibre crop in comparison to indigenous fibre is less well explored. We examine the mechanical properties of flax and two indigenous fibres (lime bast, willow bast), by testing fibre strips for tensile properties and discuss the results in the light of material choices in these periods.     

The Experimental Study of Palaeolithic Heat‐Treatment Technology: A Case from the Shuidonggou Rock Resources,North‐West China

The application of heat‐treatment technology on lithic raw materials is an important feature of early modern human behaviour. The evidence of heat‐treated stone artefacts discovered at Localities 2 and 12 of the Shuidonggou Late Palaeolithic site, North‐West China, provides an important example for studying this technology among ancient humans in Asia during the Late Palaeolithic. The mechanism and effects of heat treatment on raw materials and the role of this technology in producing stone tools were studied by means of a simulation experiment and related analytical methods. These facilitated an in‐depth analysis of the heat‐treatment activities of the Shuidonggou occupants and their implications for cognitive ability and survival strategies of human populations at that time.     

SEM,EPR and ToF-SIMS analyses applied to unravel the technology employed for pottery-making by pre-colonial Indian tribes from Pantanal,Brazil

The present work aims at elucidating the technology applied in the fabrication of ceramic objects by the ancient ceramists that inhabited the western border of Pantanal, Mato-Grosso do Sul, with the help of a multidisciplinary approach making use of chemical and physical methods of analysis. The potshards under study show the presence of different types of additives, as determined by scanning electron microscopy (SEM) and time of flight secondary ion mass spectrometry (ToF-SIMS). The dispersion of the additives within the ceramic matrix was also addressed by SEM, which shed light on the mounting technique used by the potters to assemble the ceramic vessels. Moreover, the tensile strength conferred to the pottery by the use of a specific type of additive was evaluated by applying a mechanical test. These results were correlated with the firing temperature of the potshards, determined by means of electron paramagnetic resonance (EPR).