COMPLETION OF THE SEISMIC REFRACTION SURVEY TO LOCATE THE VALLUM AT VINDOBALA,HADRIAN'S WALL*

The vallum is a major earthwork along the south side of Hadrian's Wall. All surface traces of it have been obliterated over a 500-m-long stretch past the fort of Vindobala at Rudchester, Northumberland. To the west of the fort, the vallum's course had previously been delineated by running shear-wave seismic refraction lines to obtain depth profiles of rockhead. We have now run more seismic refraction lines, using both shear waves and compressional waves, to the south-west and south of the fort, and thereby located the complete course of the vallum at Vindobala. The seismic refraction technique is successful at this site because the glacial drift cover is thin, so the vallum ditch was cut down into bedrock. During the second phase of seismic work, compressional waves gave better results than shear waves. Previously, test profiles using compressional waves had failed to locate the vallum ditch west of the fort where the surface elevation is lower; we now interpret that failure as being due to a shallow water table within the drift, which would have eliminated the compressional-wave velocity anomaly. Although the vallum does not pre-date the fort at Vindobala, its asymmetrical course around the fort suggests that it may already have been under construction to the west when the decision to build the fort was taken.     

QUICK SURVEY OF THE POSSIBLE CAUSES OF DAMAGE ENHANCEMENT OBSERVED IN SAN GIULIANO AFTER THE 2002 MOLISE,ITALY SEISMIC SEQUENCE

On October 31 and November 1, 2002, two earthquakes of magnitude 5.4 and 5.3 hit the area at the border between the Molise and Puglia regions in Southern Italy. The damage pattern in the epicentral area qualified the quake as an intensity VII MCS event, although providing a notable exception relevant to the small village of San Giuliano di Puglia. Since the first macroseismic survey, it appeared clear that in S. Giuliano the intensity was two degrees higher with respect to three neighbouring villages located within a radius of 3 km. Soon after the quake, our team started a campaign of microtremor HVSR measurements (Horizontal to Vertical Spectral Ratio), then we installed accelerometers and carried out damage and geological surveys. Finally, we performed a geoelectrical tomography and two profiles of Vs velocity with depth using the NASW technique (Noise Analysis of Surface Waves). The preliminary observations indicate that ground motion amplification is present in S. Giuliano within the frequency band that may affect building. A strong velocity contrast 20 m deep causes the predominant peak. More amplification could be due to more complicated, 2D effects. As regards the damage pattern, it divides S. Giuliano in three zones showing different characteristics and seismic behaviour. A building-by-building survey is still under way to better evaluate vulnerability variations in different zones of the village. However, the acquired data so far is sufficient to propose site amplification as a possible cause of the damage enhancement observed in S. Giuliano.     

A PRACTICAL MODEL FOR SEISMIC ANALYSIS OF REINFORCED CONCRETE SHEAR WALL BUILDINGS

A simple macro-model for reinforced concrete shear walls is proposed, which consists of spring elements representing flexure and shear behaviour. The model for flexural behaviour is based on section analysis, while the model for shear behaviour is based on key parameters of the flexural behaviour. Four wall test specimens are selected to evaluate the reliability of the model. Modelling parameters for the backbone curves and the hysteretic rules are examined by conducting static and time history analyses, with the hysteretic response of a test specimen compared to that calculated using the proposed model. Results show some differences between measured and calculated shear force versus shear distortion relationships, but the model is acceptable because the differences do not significantly affect calculated global response. Parametric studies are also conducted to examine the influence of modelling parameters on seismic demand and capacity, which are the major design parameters for structural performance evaluation. Differences due to variation in modelling parameters are not significant, further indicating that the proposed model is reasonable.     

GEOPHYSICAL SURVEY AT BODEN VEAN,CORNWALL, INCLUDING AN ASSESSMENT OF THE MICROGRAVITY TECHNIQUE FOR THE LOCATION OF SUSPECTED ARCHAEOLOGICAL VOID FEATURES*

A geophysical survey was conducted at Boden Vean, St. Anthony Meneage, Cornwall, over the site of a buried chamber thought to be the remains of a souterrain or fogou. A combination of geophysical techniques was successfully applied including an experimental microgravity survey over the location of the buried chamber itself. Magnetometer survey revealed a complex palimpsest of archaeological activity extending throughout the surrounding landscape, centred on a rectangular ditched enclosure containing the fogou. A series of gravity anomalies were recorded in the vicinity of the latter which were consistent with the collapsed section of the feature recorded by the Cornish Archaeological Unit. Further gravity anomalies suggested the presence of additional void features, possibly related to the extended passages of the fogou.     

万里长城的地理界线意义

长城,不仅是中华民族古老文化的象征,而且是一条实际存在的重要地理界线。历代长城的布设都是以自然地理环境为基础,其走向与我国半湿润与干旱气候分界线基本一致。因此,长城也就成为我国农区和牧区分界线的标志。长城的延伸或回退,基本上反映了农区与牧区的扩张或收缩。从政治地理的角度来考察长城。可以认为,它是我国历史上各民族政治力量相互对峙、较量形成的"力"的平衡带,长城,一方面发挥了分隔两个政治单元的功能,它们延伸或收缩在一定程度上反映了两种力量对比的变化;另一方面,在先进与落后两种势力的对撞中.客观上却促进了相互间经济和文化的交流,促进了不同民族的融合。今日长城作为领土扩张和防御的军事设施作用已不复存在。但是长城在地理上的许多界限指标意义仍然存在,它依然是许多地理事物的敏感地区。     

A NEW LOOK AT KINCAID: MAGNETIC SURVEY OF A LARGE MISSISSIPPIAN TOWN

Abstract

Despite extensive work by the University of Chicago in 1934–44, Kincaid has remained one of the least understood of the large mid-South Mississippian mound complexes. Between 2003 and 2009, large-scale magnetic gradient survey was done on 33.6 ha of the site, roughly half of the total site area and 65 percent of the larger and more accessible Massac County portion. The survey was highly successful, revealing large numbers of cultural features, including palisades, structures, pit features, and midden areas. This paper presents the preliminary results of the geophysical survey, complemented by small-scale groundtruthing excavations. Together these have significantly expanded and refined our understanding of this large prehistoric town. Kincaid is clearly much larger than once thought, both in terms of total site area and area of habitation. The site also exhibits much greater internal complexity, as evidenced by internal palisades and numerous small mounds and earthen platforms.     

SEISMIC RESPONSE CONTROL OF A CABLE-STAYED BRIDGE BY VARIABLE DAMPERS

Cable-stayed bridges exhibit unique responses under a strong motion. It is partly due to the complexity in their damping mechanism. Recently, the benchmark problem of a cable-stayed bridge was developed to clarify the effectiveness of various seismic control strategies. Due to the new development of magnetorheological dampers, the application of variable dampers in bridges becomes possible. In this study, the effectiveness of the nonlinear viscous damping force scheme and the two-step friction damping force scheme are investigated. It is found that the nonlinear viscous damping force scheme is effective to control the response of the cable-stayed bridge with less demand for the damping force capacity of a damper. In addition, the two-step friction damping force scheme shows the improvement over conventional friction damping because the energy dissipation of a damper can be increased.     

SEISMIC BEHAVIOUR OF A R/C WALL: NUMERICAL SIMULATION AND EXPERIMENTAL VALIDATION

This paper describes the numerical simulation of the seismic behaviour of a mock-up of a six-floor building, constituted by two parallel R/C walls and experimentally tested on a shaking table. Within the scope of an international benchmark the mock-up was submitted to three earthquakes with intensities up to 0.71 g, which induced nonlinear behaviour in the concrete and reinforcement. For the numerical simulations concrete is discretised with 2D finite elements, and its behaviour reproduced via a constitutive model with two scalar damage variables. Steel rebars are discretised with 2-noded truss elements, and their constitutive behaviour under cyclic conditions reproduced by the Menegottb-Pinto model. Specific attention is devoted to Rayleigh damping, focusing on two different strategies: (i) disregarding the damping contribution, or (ii) adopting a damping matrix that takes into account the stiffness changes during the nonlinear analyses. Main results and strategies for simulating the benchmark axe presented, with emphasis on the comparison between the numerical and the experimental results, which show good agreement when the damping contribution is neglected.     

国际直接投资国外研究动态

加入WTO后中国吸引FDI实践中出现了诸如数量大,质量差,地区分布不均,与我国产业结构调整方向不一致等突出问题。国际学者对于发展中国家吸引外资从FDI宏观决定因素、FDI进入东道国市场的模式选择、FDI区位分布等方面有着深入研究。这些研究结果可以作为我们理解我国吸引外资问题的有益借鉴:(1)东道国自身的经济运行状况、政治制度、金融制度、文化、宗教等因素组成的投资软环境已成为制约FDI流入的重要因素,应加强投资软环境的建设,为国内外企业提供有稳定良好预期的投融资环境,提高我国利用外资的质量。(2)FDI区位分布是一个动态过程,也是一个双向多边的互动过程,应正确看待来自其他国家和周边地区的影响,把政策着眼点放在如何提高FDI质量、结构的调整,而不仅仅局限于数量的增加。(3)某一个跨国公司或者同一行业内或不同行业之间的初始投资经验和业绩会对后来进入者具有示范效应。需要适应、引导和规范这种变化的功能。     

THE IMPACT OF SOLUBLE SALTS ON THE DETERIORATION OF PHARAONIC AND COPTIC WALL PAINTINGS AT AL QURNA,EGYPT: MINERALOGY AND CHEMISTRY*

The wall paintings of Al Qurna in Egypt were studied by means of XRD and ICP–AES in order to determine their mineralogical and chemical composition, and to evaluate the impact of soluble salts on their deterioration, including the identification of the building materials and pigments used. Soluble salts analysis showed that NaCl is the most common soluble salt in the bedrock, ground water and surface water samples. The building materials are affected by the ground water, while the wall paintings in the area are affected by the Upper Egypt climatic conditions, which were studied in order to detect their role in the deterioration cycle in the area.     

A DAMAGE MODEL FOR THE ANALYSIS OF THE SEISMIC RESPONSE OF MONUMENTAL BUILDINGS

In this paper the Author proposes a damage model for the analysis of masonry plates and shells, which is based on an improvement of a previous constitutive model. The modifications introduced, connected to the head joint damage, allow us to study the influence of masonry texture on the damage modes once the mechanical characteristics of the elements constituting the masonry and the results of tests on simple assemblages are known. Having a nonlinear constitutive model is certainly one of the basic elements for understanding the damage mechanisms in masonry buildings. If, in fact, an elastic-linear constitutive model may be used under normal loading conditions, in critical situations it is necessary to model the damage and the dissipation mechanisms that occur between the elements, stone (brick) and mortar, in correlation with their characteristics and kind of masonry. To validate the model a comparison is made between the numerical and experimental results, in the case of tests available in the literature in masonry panels subjected to out-of plane loading and in a real structure through the observation of the damage in Umbria (Italy) surveyed after the 1997 earthquake.     

A REASSESSMENT OF THE CHRONOLOGY OF MOUND A AT TOQUA

Abstract

The Toqua site (40MR6) is one of the most thoroughly excavated Late Mississippian mound sites in East Tennessee. The site has been a focal point of research on late prehistory in southern Appalachia, but there are issues surrounding its chronological placement. The radiometric dates obtained for the site in the 1970s and the archaeomagnetic dates reported in 1999 have large standard deviations. These dates are too imprecise to be useful for a temporal placement of the site that is clear enough for current discussions of the development of Mississippian culture. A newly obtained Accelerator Mass Spectrometry (AMS) date from the large platform mound (Mound A) allows a reevaluation of the occupation sequence of the Toqua site. This date provides an anchor for a refined chronology for Mound A. In addition to the new AMS date, this refined chronology is based on complementary lines of evidence, including architectural evidence, mortuary practices, pottery traditions, and shell gorget styles.     

INTERPRETING THE SOCIAL MEANING OF DIFFERENT SHAPES OF HOUSE STRUCTURES BY EXAMINING THE FLOW OF RESOURCES: A CASE STUDY OF SAQACENGALJ AT THE SOUTHERN TIP OF TAIWAN

Social differentiation is characterized by differences in social status and wealth, which are established and maintained by controlling and constraining the labour and flow of resources. This would affect the development of various aspects of a settlement in establishing hierarchical relationships. This study focuses on identifying the variations in the distribution of certain resources, such as imported goods, that help interpret the social meaning, particularly with regard to social status and wealth, of house structures having different shapes in an ethnic settlement in Taiwan. A petrographic study and residue analysis of the pottery along with spatial examination of the material remains were conducted to achieve the goal.     

THE ASSESSMENT OF TOTAL SEISMIC MOMENT

In this paper we address two problems: (a) the estimation of the total moment release for the calculation of average strain rates and (b) the assessment of the contribution to the total moment of earthquakes smaller than those available in regional or global catalogues. We also examine the bias associated with the different methods currently in use to estimate earthquake recurrence and total rate of seismic moment release, which are important considerations in engineering seismology and tectonics.     

基于MWVD的中心城市扩展与城市群整合研究

本文拟运用MWVD(Multiplicatively Weighted Voronoi Diagram)方法,从中心城市郑州影响区范围的历史扩展演化入手,以河南周边省会城市的发展竞争为背景,探讨中原城市群整合的方案和思路。通过定量计算与空间可视化模拟显示,得出结论:对于河南而言,仅实现郑汴一体化对于提升中心城市的辐射影响力还是不够的,必须尽早实现郑汴洛一体化,甚至中原城市群一体化,才有利于凸显组合型的辐射力和影响力。