Boerhaave's Furnace. Exploring Early Modern Chemistry through Working Models

This article discusses the (re)construction and use of an Early modern instrument, better known as Herman Boerhaave's (1668–1738) little furnace. We investigate the origins, history and materiality of this furnace, and examine the dynamic relationship between historical study and reconstructing and handling an object. We argue that combining textual analysis with performative methods allows us to gain a better understanding of both the role of lost material culture in historical chemical practice, pedagogy, and knowledge production, and provide a deeper understanding of the embodied experiences and knowledge of historical actors. Having made and used two versions of Boerhaave's furnace, we provide insight in what present-day working models can tell us about historical materials and practices approximately three centuries ago.     

X荧光成分分析实验对测量陶瓷器热释光年代的影响研究

为了考察对一件已经经过X荧光分析实验的陶瓷样品进行热释光年代测定时,年代结果是否会受到X荧光分析实验的影响及其影响程度,本工作选取了古代与现代的陶器、瓷器及三彩样品共26件,在常规、经过胎体成分分析、经过釉层成分分析三种实验条件下测量比较热释光年代的变化.研究发现,对不同时代不同类型的样品,X荧光成分分析实验对热释光测年的影响程度不同;对部分样品的测年结果无影响,对部分样品的年代有增大的影响,但增大的程度不会使热释光测年结果产生真假颠倒的结论.     

实验法探讨瓷胎元素组成和烧成温度对热膨胀法测温的影响

高温技术是我国古陶瓷科技发展史上最重要的技术成就之一,而古陶瓷测温是古陶瓷研究领域中的核心研究内容。热膨胀法具有比较直接和精确判定古陶瓷烧成温度的特点,然尚存在部分标本测量误差较大等问题。鉴于此,本研究充分考虑我国南北方古瓷胎组成配方和结构性能特点,运用实验考古学方法模拟制备具有我国古陶瓷典型瓷胎配方和不同烧结状态的标准参考样,采用热膨胀仪科学化表征瓷胎重烧热膨胀曲线上转折点与其化学组成、烧成温度间的耦合关系,并深入剖析其影响规律及内在机理,同时确立瓷胎化学组成中Al₂O₃含量和自身烧结状态是影响热膨胀法判定古陶瓷烧成温度准确性和适用性的关键技术参数。本研究有助于科学化认知现有热膨胀测温方法,补充和完善使用热膨胀仪判定古陶瓷烧成温度的方法和理论体系。     

Revisiting the potential of carbonized grain to preserve biogenic 87Sr/86Sr signatures within the burial environment

Strontium (Sr) isotope analysis of archaeological crops is a potential method of provenancing and identifying the movement of crops in the past, but there remains uncertainty about whether original ⁸⁷Sr/⁸⁶Sr values can be obtained from carbonized buried grains. We have determined that hydrochloric acid (HCl) leaching removes some, but not all, exogenous Sr from carbonized cereal grains buried in soil for up to one year. We conclude that while further work could refine the leaching method, Sr isotope analysis of archaeological cereal grains can distinguish crops sourced from outside a particular (e.g., local) area if it can be shown that leaching moves grain ⁸⁷Sr/⁸⁶Sr values significantly away from the expected Sr signature.     

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.     

New experimental evidence on the relation between percussion flaking and flake variation

Controlled experiments in percussion flaking allowed for objective analysis of relationships between variables of flake production and those variables which are attributes of the final result. The independent variables, those controlled by the flintknapper in the production of stone tools, include force and angle of blow, platform thickness and exterior platform angle. The dependent variables are those attributes of the flakes which are often used in current lithic analyses and include interior platform angle, length, thickness and flake termination. The results clearly show that exterior platform angle is highly significant for understanding many aspects of flake production. These and other relationships between the independent and dependent variables are also discussed.     

Does international recognition matter? Support for unilateral secession in Catalonia and Scotland

How much do the prospects of international recognition of a possible new state affect the domestic support for secession? To answer this research question, we adopted a most similar systems design and conducted a Web‐based survey experiment in Catalonia and Scotland. Respondents were presented with plausible scenarios regarding the international recognition of a hypothetical independent state by other countries and were subsequently asked whether they would support a unilateral declaration of independence. The results show that the prospects of international recognition as a sovereign and independent state influence the degree of support for a unilateral declaration of independence in both cases. This effect was moderated by the intensity of nationalist sentiment and the motivations for independence. Respondents with more outspoken nationalist sentiments were only marginally influenced by these scenarios or treatments. Moreover, participants whose preferences towards secession were driven by ethno‐political motivations were less influenced by international factors than those who wanted an independent state for economic or political reasons.     

Recognising burnt vein quartz artefacts in archaeological assemblages

The primary aims of this study were to determine how vein quartz behaves in an open wood fire and to suggest how burnt quartz may reliably be distinguished from unburnt quartz. Experimental burning was conducted on 10–50 mm pieces of knapped quartz collected from outcrops and beach cobbles near a later Mesolithic and Neolithic quartz scatter at Belderrig, north County Mayo, Ireland. Burning resulted in considerable fragmentation, with the majority of post-burning fragments <10 mm in size. Compared to experiments with flint, few quartz pieces were expelled from the hearth during burning, probably due to lower water content. Burning reduced the lustre and transparency of quartz and oxidized any iron-bearing rock impurities to a red-brown or pink colour, but these changes could only be diagnostic of burning where unburnt quartz of the same type is available for comparison. Burning did not affect the texture of the quartz, though quartz grain boundaries became more visible in some samples. Under the microscope, all >5 μm fluid inclusions in quartz lost their fluid contents, often with the development of fluid escape structures, and this is likely to be a reliable discriminant between burnt and unburnt vein quartz generally, even in the absence of unburnt material for comparison. Burning also creates microfractures, but this feature does not provide a diagnostic test of burning as there is considerable overlap between burnt and unburnt samples in microfracture density.     

SIMULATION OF NONLINEAR SOIL-STRUCTURE INTERACTION ON A SHAKING TABLE

A new method to simulate soil-structure interaction effects in shaking table tests has recently been presented by the authors. In this method, analog circuits or digital signal processors are used to produce soil-foundation interaction motions in real time. Their expressions of soil-structure interaction motions are based on published rigorous formulations of impulse response functions or flexibility functions of foundations resting on or embedded in homogeneous or layered soils of semi-infinite extent. In this paper the method is further extended to take the “far field” soil non-linearity into account. An example of non-linear soil-structure interaction simulation using the present method is also described.