艾比湖流域农田土壤重金属的环境风险及化学形态研究

采集土壤样品,测定8种重金属（As、Cd、Cr、Cu、Hg、Ni、Pb、Zn）的总量及各形态含量,然后采用多种方法并结合土壤背景值进行分析。结果表明：艾比湖流域农田土壤中8种重金属的含量值均未超过国家土壤质量二级标准的限值, 8种重金属可以辨识为2个主成分,重金属Cd、Hg、Pb和Zn的较高风险区主要分布在研究区的中部,重金属As、Cr、Cu和Ni的较高风险区主要分布在研究区南部靠近荒漠、山地以及研究区边缘区域,重金属As、Cr和Ni均以残渣态为主,其他形态含量较低。农田土壤中重金属的生物毒性以Cb为最大,Pb和Hg次之。     

Predicting rock mechanical properties of carbonates from wireline logs (A case study: Arab-D reservoir,Ghawar field,Saudi Arabia)

Four hundred plug samples from the Arab-D carbonate reservoir, Ghawar field, were tested for acoustic and mechanical properties at increasing triaxial stress. The results show that the rock mechanical parameters are primarily functions of porosity and, to a lesser degree, of mineralogy, texture and pore fabric (in order of degree of impact from higher to lower). The rock mechanical parameters of the intact matrix rock show no significant changes with stress under reservoir condition.     

Causes of rockfalls in AI-Huwayshah area, Yemen

According to topography of Yemen, most areas and villages are located at obligated crest, toe of mountain and under cliffs. Therefore Al-Huwayshah consisting of Tawilah sandstone group is characterized by steep slope reach to 90℃ in some areas. This area is affected by strong tectonic movements and faults that occurred during the geological epochs. This effect enhances to find out fractures and joints as well as the rocks become brittle and ready to slide depending on the position of area. And there are some fractures and joints on the surface of the areas due to tectonic movement associated with opening the Red Sea and Gulf of Aden. The rainfalls, fractures, joints, earthquakes, gravity, vegetations, temperatures and human activities play a big role in the processes of rockfalls and landslides in this area. All those factors are considered as the basic causes and catalyzed factors for occurrence of rockfall in the studide area. In addition, the authors carried out laboratory test for many rock samples to get the physical properties of the rocks.     

Hydrocarbon Generation Potential of the Organic-Rich Naifa Formation,Say’un–Masila Rift Basin,Yemen: Insights from Geochemical and Palynofacies Analyses

Natural Resources Research - The Say’un–Masila rift, one of the most important basins of Yemen, contains unconventional resources of organic-rich rocks. In the present work, geochemical...     

Groundwater protection from cadmium contamination by permeable reactive barrier in Qian＇an of Jilin, China

This research studies the reliability of an activated carbon permeable reactive barrier in removing cadmium from a contaminated shallow aquifer. Laboratory tests have been performed to characterize the equilibrium and kinetic adsorption properties of the activated carbon in cadmium-containing aqueous solutions. A 2D numerical model has been used to describe pollutant transport within a groundwater and the pollutant adsorption on the permeable reactive barrier （PRB）. In particular, it has been considered the case of a PAB used to protect a lake or downstream from Cd （II） contaminated groundwater. Numerical results show that the PAB can achieve a long-term efficiency by preventing lake or downstream pollution for several months.     

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in harbor sediments from Sea Lots, Port-of-Spain, Trinidad and Tobago

Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in nearshore marine surficial sediments from three locations in Trinidad. Sediments were sampled at Sea Lots on the west coast, in south Port-of-Spain Harbor, south of Sea Lots at Caroni Lagoon National Park, and on Trinidad’s east coast at Manzanilla. Total PCB concentrations in Sea Lots sediments ranged from 62 to 601 ng/g (dry weight {dw}), which was higher than at Caroni and Manzanilla, 13 and 8 ng/g dw, respectively. Total OCP concentrations at Sea Lots were ranged from 44.5 to 145 ng/g dw, compared with 13.1 and 23.8 n/g (dw), for Caroni and Manzanilla respectively. The concentrations of PCBs and of some OCPs in sediments from Sea Lots were above the Canadian interim sediment quality guidelines. To date, this data is the first report on the levels of PCBs and other organochlorine compounds from Trinidad and Tobago.     

Cross-calibration of DIMM monitors at Oukaimden observatory and Marrakesh site

Over the past years, several differential image motion monitors (DIMM) have been built almost everywhere. The DIMM instrument is made up of simple material such as telescope, mask, camera ..., and it is widely used in seeing measurement campaigns. In order to carry out a prospecting campaign, for the European Extremely Large Telescope (ELT) project, in the Moroccan High Atlas, we have built a new DIMM instrument in our laboratory. To characterize this instrument, we have carried out a cross-calibration between DIMM monitors using different configurations. In this paper we will present the results of those various experiments respectively at Oukaimden site and at the “École Normal Supérieure” (ENS) in the city of Marrakech.     

Multiple reference consistency check for LAAS: a novel position domain approach

Since the traditional Maximum Likelihood-based range domain multiple reference consistency check (MRCC) has limitations in satisfying the integrity requirement of CAT II/III for civil aviation, a Kalman filter-based position domain method has been developed for fault detection and exclusion in the Local Area Augmentation System MRCC process. The position domain method developed in this paper seeks to address the limitations of range domain-based MRCC by focusing not only on improving the performance of the fault detection but also on the integrity risk requirement for MRCC. In addition, the issue of the stability of the Kalman filter in relation to the position domain approach is considered. GPS range corrections from multiple reference receivers are fused by the adaptive Kalman filter at the master station for detecting and excluding the single reference receiver’ failure. The performance of the developed Kalman filter-based MRCC has been compared with the traditional method using experimental data. The results reveal that the vertical protection level is slightly better in the traditional method compared with the developed Kalman filter-based approach under the fault-free case. However, the availability can be improved to over 97% in the proposed method relative to the traditional method under the single-fault case. Furthermore, the fault-tolerant positioning result with an accuracy improvement of more than 32% can be achieved even if different fault types are considered under the single-fault case. In particular, the algorithm can be a candidate option as an augmentable complement for the traditional MRCC and can be implemented in a master station element of the LAAS integrity monitoring architecture.     

The Jinadriyah anticlines: a surface model for oil fields in eastern Saudi Arabia

Mesozoic oil in Saudi Arabia exists in north/south-oriented anticlines. Such anticlines are usually studied using subsurface data. The present study introduces, for the first time in Saudi Arabia, a surface analog for these anticlines. The study covers two northerly oriented anticlines located in the Jinadriyah area at 15 km to the northeast of the Riyadh city. They are named herein the North and South Jinadriyah anticlines. The outcrops in both anticlines belong to the Lower Cretaceous Yamama Formation which consists of limestone in its lower part and limestone with shale in its upper part. The study included initially detailed interpretation of Google Earth and Landsat TM images to map the structural pattern of the anticlines. Detailed field mapping confirmed the satellite image interpretation and helped describe the geometry of the two anticlines in detail. The 3.5-km-long South Jinadriyah anticline is an open doubly plunging asymmetric anticline. The western flank is dissected by 13 minor reverse faults of north–south orientation. The North Jinadriyah anticline is about 5.5 km long and is relatively more complex than the South Jinadriyah anticline. It consists of northern, central, and southern segments that differ from each others in orientation and style. The anticline is dissected by 18 minor faults of different orientations and sense of displacement. Two perpendicular fracture sets with one being parallel to the anticline axes were recorded in the two anticlines. Both anticlines are interpreted as fault-propagation folds that were formed during the Late Cretaceous first Alpine orogeny. The mid-Late Tertiary second Alpine orogeny and Late Tertiary eastward tilting of the Arabian Plate increased the degree of folding and faulting.