THE ACCURACY OF THE SPECIFIC GRAVITY METHOD FOR THE ANALYSIS OF GOLD ALLOYS

Two possible sources of error in the measurement and interpretation of the specific gravities of gold coins are investigated. First, the effect of the presence of copper was measured and found to be more significant than previously thought. It is shown that the presence of 5% of copper in a gold-silver alloy results in a measured gold content which is 3.3% too low when the coin is analysed by the specific gravity method. Secondly, the importance of cleaning the coins before measuring the specific gravity is also demonstrated.     

A SIMPLIFIED METHOD FOR ELASTIC SEISMIC ANALYSIS OF HILL BUILDINGS

Abstract

Buildings on hill slope are highly irregular and asymmetric in plan and elevation. They are subjected to severe torsion in addition to lateral forces under the action of earthquakes. In the present study, simplified 3D dynamic analysis of hill buildings based on transformation of stiffness and mass of various components about a common arbitrarily-chosen reference axis is presented. Few actual hill building problems have been analysed with the simplifed method and the rigorous method of analysis. The results of the two methods of analysis advocate the use of the simplified method in the Code of Practices of different countries. With the use of the simplified method, the configurations for buildings on hill slope can be decided by taking various trial configurations so as to obtain the most economical and safe design from the seismic point of view.     

A SIMPLE METHOD FOR ANALYSIS OF SLIDING STRUCTURES CONSIDERING VARIATIONS OF FRICTION COEFFICIENT

In this paper, the responses of multidegree of freedom (MDOF) structures on sliding foundations, subjected to harmonic or random base motions, are investigated taking into consideration the variations of friction forces. The variation of friction force is a consequence of variation of friction coefficient, which depends on such parameters as relative velocity and the existing pressure. Modelling of the friction force under the foundation raft is accomplished by using a fictitious rigid link with a rigid-perfectly plastic material. This results in identical equations of motion for the sliding structure, both in the sliding and nonsliding (stick) phases and considerably decreases the required number of time steps for the nonlinear analysis. Since the force in the link is of constant value, to consider the varying friction force, a compensatory force, which is the difference between the exact friction force and the constant force in the rigid link, is applied to the foundation raft. A model of variable friction coefficient for Teflon-steel interfaces is used for the assessment of the method and the results are compared with existing literature, through which, the capability of the method is illustrated. It is shown that by using exact model of friction lower values for the superstructure responses are predicted compared with those obtained by using Coulomb friction model. Furthermore the effect of the stiffness of the structure on the differences between the results of the two models is also studied.     

THE USE OF SPECIFIC HEAT IN THE NON-DESTRUCTIVE ANALYSIS OF SILVER/COPPER ALLOY COINS

Using partly plastic apparatus, specific heats of coins have been found calorimetricly to an accuracy of ± 3% for most coins. For silver/copper alloys the specific heat varies approximately linearly with the weight percentage composition, so the latter can be calculated for coins of unknown composition.     

A NEW METHOD FOR THE DETERMINATION OF THE PROVENANCE OF WHITE MARBLES BY CHEMICAL ANALYSIS OF INCLUSION FLUIDS: THE MARBLES OF THE MAUSOLEUM OF BELEVI/TURKEY*

A new method is presented in this paper to pinpoint the origin of white marbles using the chemical analysis of fluids occurring as micro-inclusions in calcitic or dolomitic marbles. Beside the conventional methods usually applied for this purpose, the analyses of significant anions and cations in fluids extracted from white marbles were used to characterize different types of marbles. Using this new approach it is possible to distinguish different groups of marbles which cannot be separated isotopically. A case study was performed on the mausoleum of Belevi, close to Ephesus in Turkey, and the quarries in the area of the mausoleum. The marbles used for the architecture of the mausoleum cannot be distinguished isotopically but were split into two groups when using fluid inclusion analysis. The corresponding quarry for the high-quality marble (cella walls, columns etc.) turned out to be the Kentli Çiftliği quarry, which also supplied the marbles for the classical Artemision. According to the chemical and fluid data it can be shown, however, that neither the adjacent famous antique quarry of Belevi nor the underground mine of Kusini, some 5 km away from the mausoleum, are the sources for the marbles used for the construction or decoration of the mausoleum.     

THE ANALYSIS OF GOLD COINS—A COMPARISON OF RESULTS OBTAINED BY NON-DESTRUCTIVE METHODS

This paper discusses a systematic difference between the results found when one series of Dark-Age gold coins were analysed both by neutron activation and by specific gravity analysis and when a second series of similar coins was analysed by the Oxford Milliprobe and by specific gravity. No reason is given for this systematic difference, although there is evidence that all three methods are slightly in error, two of them giving results for gold which are too high and the specific gravity method giving results which are too low.     

A 'MATRIX TECHNIQUE FOR THE ANALYSIS OF INTERRUPTED DITCH ENCLOSURES

Summary. A method is presented for the graphic display of data reflecting the physical form of neolithic interrupted ditched enclosures.     

A DOUBLE-ENTRY METHOD FOR THE CONSTRUCTION OF BI-REGIONAL INPUT-OUTPUT TABLES*

ABSTRACT. In The Netherlands, a strong tradition in the construction and updating of (inter)regional input-output tables has been built up. The paper gives a brief overview of this Dutch experience and discusses the features of the by now more or less standardized double-entry bi-regional construction method (DEBRIOT). This method systematically adds sales and export coefficients to the usual construction procedures. Thus, it introduces consistency checks at the cell level of the input-output table. Moreover, it offers a non-survey technique to estimate a regional domestic sales table that is crucial to the double-entry character of the method.     

BARBARIAN PIRACY AND THE SAXON SHORE: A REAPPRAISAL

Summary.   The tradition of Saxon and other Continental piracy is one of the longest standing tenets of Romano-British studies. It may also be one of its greatest myths, which owes more to its considerable antiquarian pedigree than to any firm basis in fact. This paper reassesses Roman military strategy around the British coast, and suggests that the 'Saxon Shore Forts' and other coastal installations played a more significant economic and logistical role than is often appreciated. Moreover, the idea that each monument fulfilled a single, dedicated function is argued to be too simplistic: instead it is proposed that individual forts served in various capacities during their operational lifetime, and quite possibly not those for which they were originally conceived.