AIMS Low socioeconomic status is associated with increased cardiovascular disease risk. We hypothesized that psychobiological pathways, specifically slow recovery in blood pressure and heart rate variability following mental stress, partly mediate social inequalities in risk. METHODS AND RESULTS Participants were 123 men and 105 women in good health aged 47-58 years drawn from the Whitehall I...

The aim of this study is to optimize performance functions of turbofan engines considering the off-design model of turbofan engine as well as employing multi-objective genetic algorithm. The design variables including high-pressure compressor pressure ratio, low-pressure compressor pressure ratio, fan pressure ratio and bypass ratio are calculated in such a way that the corresponding functions ...

PURPOSE This study evaluated the effect of Tai Chi Chuan (TCC) on the autonomic nervous modulation in older persons. METHODS Twenty TCC practitioners and 20 normal controls were included in this study. The stationary state spectral heart rate variability (HRV) measures between TCC practitioners and normal controls, and the sequential changes in HRV measures after classical Yang's TCC were com...

The accurate prediction of wellbore temperature distribution helps to accurately estimate well pressure profile and bottom-hole pressure (BHP) which is important in the under-balanced drilling (UBD) operation. In this paper effect of temperature variation due to heat transfer of drilling fluid with the formation and also oil and gas production from the reservoir into the annulus in under-balanc...

This paper presents analytical solutions and simulations for pressure transient behavior of the partially penetrating wells (PPWs). The Newman’s product method was adopted to develop the basic instantaneous source functions which characterize the response of PPWs. These results were obtained based on the solution of fully penetrating wells (FPWs) and they were presented in Laplace domain. Furth...

Determination of the borehole and fracture initiation positions is the main aim of a borehole stability analysis. A wellbore trajectory optimization with the help of the mud pressure may be unreasonable since the mud pressure can only reflect the degree of difficulty for the initial damage to occur at the wellbore rather than the extent of the wellbore damage. In this work, we investigate...

Even with the fractured wells, primary oil recovery of low-permeability reservoirs is still poor in Block X Shengli Oilfield. To further enhance recovery, water injected into reservoir. Different from conventional injection scheme, maximum daily rate proposed scheme by Oilfield reaches 2000 m3, and average around 1500 m3. Thus, well spacing certain pattern not suitable for novel scheme. In pape...

Hydraulic conductivity variations around the boreholes in uniformly graded sands for cyclic water injection pressure have been evaluated by laboratory tests. Prototype laboratory devices have been designed and constructed for this research. The cell has a capability to model the well, the boundary condition and to measure the hydraulic conductivity. While increasing water injection pressure, hy...

control of well drilling operations poses a challenging issue to be tackled. the loss of well control could lead to the occurrence of blowout as a severe threat, involving the risk of human lives and environmental and economic consequences. conventional proportional-integral (pi) controller is a common practice in the well control operation. the small existing margin between pore pressure and f...