Red Sea palaeoclimate: stable isotope and element-ratio analysis of marine mollusc shells

The southern Red Sea coast is the location of more than 4,200 archaeological shell midden sites. These shell middens preserve archaeological and climatic archives of unprecedented resolution and scale. By using shells from these contexts, it is possible to link past environmental information with episodes of human occupation and resource processing. This chapter summarises current knowledge about the marine gastropod Conomurex fasciatus (Born 1778) and discusses its use in environmental and climatic reconstruction using stable isotope and elemental ratio analysis. It offers a review of the most recent studies of shell midden sites on the Farasan Islands, their regional importance during the mid-Holocene, theories about seasonal use of the coastal landscape, and preliminary results from new methods to acquire large climatic datasets from C. fasciatus shells

Using the acoustic sound pressure level for quality prediction of surfaces created by abrasive waterjet

The paper deals with an innovative way of cutting materials by abrasive waterjet with a view to increase its quality. In the research work, we were concerned with the search for a relationship between surface roughness and noise in the abrasive waterjet cutting process. Innovation lies in the use of negative characteristic of the technology—noise, which is a carrier of information about the quality of cutting process. In this way, the noise can be positively used in the on-line control of the technological process. The final result is a project for control of the process of abrasive waterjet cutting of materials by means of feedback according to the on-line measurement of acoustic pressure level L aeq (dB). Instantaneous information about the state of cut according to the instantaneous value of L aeq amplitude allows the automatic regulation of traverse speed of cutting head v p (mm.min−1), which is, together with the pressure p (MPa), one of the most important technological factors of control of production technology from the point of view of economic indicators and qualitative indicators of a semiproduct. The proposed model has been experimentally verified and was simulated in Matlab

Determination of technologically optimal factors of modulated waterjet

This paper deals with two methods of determination of technologically optimal factors of a hydrodynamic resonance system leading to the acquiring of maximal fundamental frequency, amplitude, pressure, and energy of oscillations of a liquid jet. These factors are determined by the differential method and the method of state space search into depth. Furthermore, theoretically predicted results are presented, interpreted, and compared with results of laboratory measurements. The benefit of the study is the optimization itself, either for the optimal input factors of the prototype or a maximum possible modification of existing equipment in order to achieve the highest possible material disintegration efficiency.Web of Science601-417917

Pre-Hispanic Fishing Structures Preserved on the Central Coast of Ecuador

Marine resource exploitation is documented for the central coast of Ecuador from 10.000 yr B.P., with a wide range of fishing techniques developing through time. Most recently, dozens of stone fishing structures have been identified at the Liguiqui archaeological locality, on the Manta Peninsula of Manabí Province. These resemble fish traps such as have been recorded worldwide, though no similar devices have previously been reported on the Pacific coast of tropical or subtropical South America. A preliminary study of the Liguiqui structures is presented here, assessing their geologic, environmental, cultural and chronological context. It is hypothesized that they could have had a double function as fish traps and as fish attractors/containers, and that they were most likely built during the Pre-Hispanic Manteño cultural period.Fil: Favier Dubois, Cristian Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Storchi Lobos, Daniela. Universidad de Buenos Aires. Facultad de Filosofía y Letras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lunniss, R.. Universidad Técnica de Manabí; EcuadorFil: Mora Mendoza, A.. Escuela Superior Politécnica del Litoral; EcuadorFil: Ortiz Aguilú, J. J.. Universidad Técnica de Manabí; Ecuado