The meteoritic origin of Tutankhamun's iron dagger blade

Scholars have long discussed the introduction and spread of iron metallurgy in different civilizations. The sporadic use of iron has been reported in the Eastern Mediterranean area from the late Neolithic period to the Bronze Age. Despite the rare existence of smelted iron, it is generally assumed that early iron objects were produced from meteoritic iron. Nevertheless, the methods of working the metal, its use, and diffusion are contentious issues compromised by lack of detailed analysis. Since its discovery in 1925, the meteoritic origin of the iron dagger blade from the sarcophagus of the ancient Egyptian King Tutankhamun (14th C. BCE) has been the subject of debate and previous analyses yielded controversial results. We show that the composition of the blade (Fe plus 10.8 wt% Ni and 0.58 wt% Co), accurately determined through portable x‐ray fluorescence spectrometry, strongly supports its meteoritic origin. In agreement with recent results of metallographic analysis of ancient iron artifacts from Gerzeh, our study confirms that ancient Egyptians attributed great value to meteoritic iron for the production of precious objects. Moreover, the high manufacturing quality of Tutankhamun's dagger blade, in comparison with other simple‐shaped meteoritic iron artifacts, suggests a significant mastery of ironworking in Tutankhamun's time.     

Polarization Light Curves and Spectra of AM-Her Polars

Some polarization spectra and light curves are being generated to explore the properties of AM-Her(culis) shocks for which the cyclotron emission is self-consistently calculated. Here, we quantify several of the relationships between the polarization and the properties of the magnetic field for magnetic white dwarf oscillating radiative accretion shocks. We discuss the properties of the polarization for time scales ≫ tosc, the oscillation period of the radiative shocks. The time-averaged polarization curves are calculated for a polar cap composed of independently oscillating flux tubes. We choose our funnels to cover the polar cap subtending an angle of 18° from the polar axis. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hydrogeological aspects of groundwater drainage of the urban areas in Kuwait City

Residential areas in Kuwait City have witnessed a dramatic rise in subsurface water tables over the last three decades. This water rise phenomenon is attributed mainly to over irrigation practices of private gardens along with leakage from domestic and sewage networks. This paper presents a comprehensive study for urban drainage in two selected areas representing the two hydrogeological settings encountered in Kuwait City. In the first area, a vertical drainage scheme was applied successfully over an area of 1 km². The system has been under continuous operation and monitoring for more than 4 years without problems, providing a permanent solution for the water rise problem in this area. The hydrogeological system has approached steady state conditions and the water levels have dropped to about 3·5 m below the ground surface. In the second area a dual drainage scheme, composing of horizontal and vertical elements, is proposed. Horizontal elements are suggested in the areas where the deep groundwater contains hazardous gases that may pose environmental problems. The proposed drainage scheme in the second area has not yet been implemented. Field tests were conducted to assess the aquifer parameters in both areas and a numerical model has been developed to predict the long‐term response of the hydrogeological system in the two areas under consideration. Copyright © 2001 John Wiley & Sons, Ltd.     

Fifty years of stacking

Common-Mid-Point (CMP) stacking is a major process to enhance signal-to-noise ratio in seismic data. Since its appearance fifty years ago, CMP stacking has gone through different phases of prosperity and negligence within the geophysical community. During those times, CMP stacking developed from a simple process of averaging into a sophisticated process that involves complicated mathematics and state-of-the-art computation. This article summarizes the basic principles, assumptions, and violations related to the CMP stacking technique, presents a historical overview on the development stages of CMP stacking, and discusses its future potentiality.     

Modeled Influence of East Asian Black Carbon on Inter-Decadal Shifts in East China Summer Rainfall

Two inter-decadal shifts in East China summer rainfall during the last three decades of the 20th century have been identified.One shift occurred in the late 1970s and featured more rainfall in the Yangtze River valley and prolonged drought in North China.The other shift occurred in the early 1990s and featured increased rainfall in South China.The role of black carbon(BC) aerosol in the first shift event is controversial,and it has not been documented for the second event.In this study,the authors used Geophysical Fluid Dynamics Laboratory's(GFDL's) atmospheric general circulation model known as Atmosphere and Land Model(AM2.1) ,which has been shown to capture East Asian climate variability well,to investigate these issues by conducting sensitive experiments with or without historical BC in East Asia. The results suggest that the model reproduces the first shift well,including intensified rainfall in the Yangtze River and weakened monsoonal circulation.However,the model captures only a fraction of the observed variations for the second shift event.Thus,the role of BC in modulating the two shift events is different,and its impact is relatively less important for the early 1990s event.     

2-D electrical imaging in some geotechnical investigation of Madhupur clays,Bangladesh

Electrical imaging or electrical tomography is a survey technique suitable for the investigation of areas of shallow complex geology, where the use of other electrical and electromagnetic techniques is less effective. An electrical image has been delineated at a site located in front of the Department of Geological Sciences, Jahangirnagar University, Dhaka, Bangladesh. 16 soil samples were collected from two boreholes located on the image line and geotechnical parameters such as unit weight, water content, grain size, plastic limit, liquid limit and plasticity index were measured in the laboratory. These geotechnical parameters were compared with the measured electrical resistivity.     

基于静稳天气下气球探空实验的中国沙漠地区沙尘气溶胶的垂直分布（英文）

塔克拉玛干沙漠是亚洲沙尘气溶胶的重要源地。为探讨塔克拉玛干地区沙尘气溶胶的理化特性与时空变化,研究其环境与气候效应,本文分析了四个季节在中国敦煌(塔克拉玛干沙漠内)取得的探空气球观测数据,包括气溶胶的数浓度、粒径分布、质量浓度及在西风主导下的水平输送通量。气溶胶数浓度的垂直廓线显示,来自沙漠地区的矿物粒子对局地环境与气候有重要影响,且所有季节都存在长距离输送。粒子谱分布显示局地有大量粗粒子输入。结果说明,源于塔克拉玛干沙漠的沙尘气溶胶的背景输送有着重要的科学意义,需进一步研究其对东亚和西太平洋地区环境与气候的影响。     

Impact of European Black Carbon on East Asian Summer Climate

The remote response of the East Asian summer monsoon(EASM)to European black carbon(EUBC)aerosols was studied by using an ensemble of sensitivity experiments with the Geophysical Fluid Dynamics Laboratory(GFDL)atmospheric general circulation model(AGCM)Atmospheric Model version 2.1(AM2.1).The results show that EUBC causes an enhanced EASM.The resulted enhanced southwesterly brings more moisture supply from the Bay of Bengal,which causes an increase in precipitation over the Yangtze River valley,northeastern China,the eastern part of the Yellow River valley,and the Tibetan Plateau.Diagnostic examination suggests that EUBC induces enhanced tropospheric heating over most of the Eurasian Continent through a propagating wave train and horizontal air temperature advection.This phenomenon results in intensified thermal contrast between land and ocean,which accounts for the enhanced EASM.Moreover,reductions in EUBC emission in 1992 may have contributed to decadal weakening of the EASM in the early 1990s.