Scientific selection of drill bits during drilling is a key technology to achieve high-speed drilling and reduce drilling costs. Based on the analysis of bit’s working principles and its applicable conditions and in accordance with the well conditions of ultra-deep wells in Y area of Tarim Oilfield, this study has conducted mathematical statistics on a large number of actual drilling practices ...

in recent years, the groundwater resources in guilan province have played an important role in irrigating paddy fields. the goal of this study was to evaluate temporal and spatial variations of groundwater quality in a 4-year period using ordinal kriging. water samples for this study were collected from 130 wells across guilan province, in september and march from 2003 to 2006.  maps of ec and ...

information on nitrate in groundwater resources requires periodic measurements are accurate. despite the measure in some areas due to sensitive social and health community are not reported. therefore, be informed of the status of each area of water quality, modeling is essential. the purpose of this study was the application of artificial neural network method for estimating nitrate and compare...

Arsenic, a semi-metal, colourless, tasteless and odourless toxic element, is known as the “King of Poison” at present. Arsenicosis is a well-known chronic disease which occurs due to drinking of arsenic contaminated tube well water having arsenic level exceeding the normal level for a prolonged period. It is likely to create a significant health impact ranging from skin lesions to cancer culmin...

Purpose: The Wells rule is widely used for clinical assessment of patients with suspected deep vein thrombosis (DVT), especially in the secondary care setting. Recently a new clinical decision rule for primary care patients (the primary care rule) has been proposed, because the Wells rule is not suffi cient to rule out DVT in this setting. The objective was to compare the ability of both rules ...

BACKGROUND Recent studies showed that preoperative deep vein thrombosis (DVT) was common after hip fracture (HF), and preoperative DVT screening has been recommended for preventing the fatal DVT-related complications, especially in elderly HF patients with high surgical risk. However, to our knowledge, no previous studies have demonstrated the correlation between the clinical risk predictors an...

PURPOSE The Wells rule is widely used for clinical assessment of patients with suspected deep vein thrombosis (DVT), especially in the secondary care setting. Recently a new clinical decision rule for primary care patients (the primary care rule) has been proposed, because the Wells rule is not sufficient to rule out DVT in this setting. The objective was to compare the ability of both rules to...

Groundwater and raw water pollution risks of pesticides were assessed by analyses of groundwater samples and by modelling groundwater flow and chemical transport with a coupled model ‘train’ consisting of: a regional Modflow model for simulation of groundwater flow in the saturated zone (IBRAHYM, TNO 2007)) a 1-D model for simulation of water and pesticide transport in the unsaturated zone (PEA...

Directional drilling and hydraulic-fracturing technologies are dramatically increasing natural-gas extraction. In aquifers overlying the Marcellus and Utica shale formations of northeastern Pennsylvania and upstate New York, we document systematic evidence for methane contamination of drinking water associated with shale-gas extraction. In active gas-extraction areas (one or more gas wells with...