郑州商文化陶字符量化分析

对郑州商文化陶字符量化分析结果显示,早商文化陶字符使用以具有首都地位的郑州早商文化遗址最为集中,具有较强的地域性。郑州早商文化陶字符分期演进中出现一些分界现象,缘于商文化的兴盛和文化中心的转移。郑州商文化陶字符多出现于祭祀场所和手工业作坊遗址具有特殊意义的遗迹,表明其主要为生活、手工业生产、祭祀活动中有关数量、日期、位序、族属、地点等信息的记录遗存。     

舞阳贾湖墓葬的统计学初步分析

本工作旨在了解贾湖单人墓随葬品数量与墓主人性别、年龄以及墓葬分期之间的关系。根据墓葬样本的实际情况,本工作使用t-检验、单因素和双因素方差分析的方法进行了初步的统计学分析。结果显示,贾湖墓葬随葬品总量与性别无关,但与墓主人的死亡年龄有关,壮年随葬品较丰富。同时,随葬品数量受到性别和死亡年龄的交互影响比较显著,女性少年儿童的随葬品数量最多,男性壮年的随葬品次之。从随葬品的种类上看,除少年儿童组最多外,女性壮年墓葬占有石制品最多;男性壮年墓葬占有骨、牙制品最多。本工作还发现陶器和骨、牙制品的数量在不同时期存在着较显著变化,第二期时骨、牙制品和陶制品的数量较多。本工作认为,女孩随葬品数量较多的情况可能与母系氏族社会重女习俗有关,不同性别的壮年侧重随葬不同质地的物品则可能暗示着贾湖先民们已经出现了一定程度的社会分工,陶和骨、牙制品在第二期时比较丰富的现象可能与这一时期渔猎采集活动较活跃有关。     

“华光礁一号”南宋沉船船板中硫铁化合物分析

鉴于硫铁化合物对海洋出水木质文物的特殊危害,通过 X射线衍射(XRD)、等离子体发射光谱(ICP-AES)和 X射线光电子能谱(XPS)等分析手段,对“华光礁一号”南宋沉船船板残块中的硫铁化合物进行了分析研究。结果表明,所采集的样品中含有大量的 Fe和 S元素,并且其分布深度至少可达 4cm。两种元素的化学状态基本可分为铁的氧化物、硫铁化合物、硫酸盐和其它还原性硫四大类。其中,硫铁化合物主要以 FeS和 FeS₂形式存在,并已部分氧化成硫酸盐。因此,在后续的保护处理过程需着重对其酸化过程进行控制,以有利于文物的长期保存。     

The oldest evidence of painted furniture from Sweden – The 12th century chair from Suntak

The 12th century Suntak chair is one of the earliest pieces of furniture known from Sweden. A close examination revealed minute remnants of possible colour pigments on several parts of the chair. Chemical analyses of the pigments revealed the presence of several colours such as black, white and red. This paper attempts to shed light upon the identification and origin of the pigments as well as the time of painting. The original use and the setting of the chair will also be discussed.     

Late medieval copper alloying practices: a view from a Parisian workshop of the 14th century AD

161 late medieval copper-based day-to-day items have been analysed, mostly consisting of small artefacts such as dress fittings. The items were all recently excavated from a 14th century AD metallurgical workshop located in Paris. Eight well-defined copper alloys have been identified that refer to various constraints, the most important one being economics. According to the model proposed, most of the alloys were obtained by dilution of a fresh brass master alloy by scrap metal containing small amounts of zinc, tin and lead. Pure lead was added separately in relatively large quantities, with a limit of 6 wt% Pb marking the boundary between leaded and unleaded alloys. It has been found that the less the cost of the artefact, the more the fresh brass is diluted. For the medium-size castings such as cast vessels, alloys containing large quantities of lead or alloys rich in antimony were used. Such complex alloying strategy pertains more to a small industrial-like plant organisation rather than to craftsman activity, as further supported by a variety of archaeological and historical evidence.     

SHAPE MEMORY ALLOYS IN SEISMIC RESISTANT DESIGN AND RETROFIT: A CRITICAL REVIEW OF THEIR POTENTIAL AND LIMITATIONS

Shape memory alloys (SMAs) are a class of materials that have unique properties, including Young's modulus-temperature relations, shape memory effects, superelastic effects, and high damping characteristics. These unique properties, which have led to numerous applications in the biomedical and aerospace industries, are currently being evaluated for applications in the area of seismic resistant design and retrofit. This paper provides a critical review of the state-of-the-art in the use of shape memory alloys for applications in seismic resistant design. The paper reviews the general characteristics of shape memory alloys and highlights the factors affecting their properties. A review of current studies show that the superelastic and high-damping characteristics of SMAs result in applications in bridges and buildings that show significant promise. The barriers to the expanded use of SMAs include the high cost, lack of clear understanding of thermo-mechanical processing, dependency of properties on temperature, and difficulty in machining.     

FRAGILITY OF STANDARD INDUSTRIAL STRUCTURES BY A RESPONSE SURFACE BASED METHOD

National and international regulatory standards require industrial risk assessment, taking into account natural hazards including earthquakes, in the framework of Quantitative Risk Analysis (QRA). Seismic fragility analysis of industrial components may be carried out similarly as what has been done for buildings, even though some peculiar aspects require the development of specific tools. In the present paper a contribution to the definition of a rational procedure for seismic vulnerability assessment of standardised industrial constructions in a probabilistic framework is given. The method covers a range of components of the same structural type. Seismic reliability formulation for structures is used. Both seismic capacity and demand are considered probabilistic with the latter assessed by dynamic analyses. The application example refers to shell elephant foot buckling of unanchored sliding tanks. A regression-based method is applied to relate fragility curves to parameters varying in the domain of variables for structural design.     

Physical and Numerical Approaches for the Optimal Insertion of Seismic Viscous Dampers in Shear-Type Structures

This article presents the results of an exhaustive parametric analysis which compares the performances offered by various systems (which lead to both classical and non classical damping matrices) of added viscous dampers in shear-type structures. The aim of the research work here presented is the identification of the system of added viscous dampers which maximizes the dissipative properties under an equal “total size” constraint. The choice of the systems of added viscous dampers considered in the comparison is carried out both using a numerical approach (based upon the use of genetic algorithms) and a physically based approach (based upon the properties of classically damped systems). The comparison is carried out through the numerical evaluation of the dynamic response of representative shear-type structures to both stochastic and recorded earthquake inputs. The results obtained using both approaches indicate that a damping system based upon the mass proportional damping component of the Rayleigh viscous damping matrix (referred to as MPD system) is capable of optimizing simultaneously a number of different performance indexes, providing the best “overall” damping performances. The MPD system is characterised by viscous dampers (a) which connect each floor to a fixed point and (b) which are sized proportionally to the corresponding floor mass.     

Inelastic Demand Spectra of Bi-Linear Models for Capacity Spectrum Method and Response of Simple Structures under Near-Source Records

A very useful tool for the preliminary design of structures is the elastic demand spectrum that can be used in the capacity spectrum method. A pseudo-acceleration relationship has to be assumed when constructing a demand spectrum. This assumption results in large errors for long period structures with large damping ratios and the conventional demand spectra require a substitute elastic structure. In the present study, the conventional demand spectra are extended to bi-linear models. Pseudo-acceleration is still assumed but results in acceptably small errors, when a constant viscous damping coefficient for a single-degree-of-freedom (SDF) structure is calculated from the tangent stiffness and the damping ratio is set at 5% in both elastic and yield phases. For nonlinear structures, tangent stiffness dependency of damping force could be acceptable because energy absorption is primarily the result of structural nonlinear deformation. To extend the conventional demand spectra to a bi-linear model, effective period calculated from the secant stiffness has to be used. The use of effective period introduces no approximation because the peak displacement of the SDF structure is computed from nonlinear analysis in the time domain. The method presented in this study is also valid if damping coefficient proportional to initial elastic spectra is used. In this case, the pseudo-acceleration is defined as the base shear coefficient that is required to produce the peak displacement of the SDF structure in a static manner. We present demand spectra of bi-linear models for a number of near-source records from large earthquakes, and spectral ratios of two horizontal components. The effects of different types of ground motion on the response reduction factor due to inelastic deformation are investigated.     

Seismic Resistance Evaluation of Unreinforced Masonry Buildings

The article presents seismic resistance evaluation study of unreinforced brick masonry buildings. The study was carried out as part of the Ph.D. research work of the first author. As part of the study, in addition to the standard laboratory tests, a dynamic field test was carried out on single-story, single-room unreinforced masonry structure. The model structure was tested in actual ground conditions against simulated earthquake vibrations produced through controlled explosions, especially designed for this purpose. Based on masonry properties accrued from lab and field tests, finite element models of the brickwork system were also studied. Finally, the software named, “Shear Damage Index (SDI),” developed as part of this study, was used to plot contours of shear demand (shear stress) to shear capacity (shear strength) ratio on the numerical model and hence to identify potential weak zones in the model for possible strengthening of those locations.