W UMa Research Articles

Optic Imaging of Two-Phase-Flow Behavior in Nanoscale Fractures

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 164549, ’Optic Imaging of Two-Phase-Flow Behavior in Nanoscale Fractures,’ by Qihua Wu, Baojun Bai, SPE, and Yinfa Ma, Missouri University of Science and Technology; and Joeng Tai Ok, Keith Neeves, and Xiaolong Yin, SPE, Colorado School of Mines, prepared for the 2013 SPE Unconventional Resources Conference, The Woodlands, Texas, USA, 10-12 April. The paper has not been peer reviewed. Gas in tight sand and shale exists in underground reservoirs with microdarcy or even nanodarcy permeability ranges; these reservoirs are characterized by small pore throats and crack-like interconnections between pores. The physics of fluid flow in these rocks, with measured permeability in the nanodarcy range, is poorly understood. Knowing the fluid-flow behavior in the nanoscale channels is of major importance for both simulation studies and calculations of the relative permeability of gas in tight shale-gas systems. Introduction Shale-gas reservoirs have pore sizes in the range of 1 to 300 nm. Additionally, the matrix permeabilities of those unconventional gas reservoirs are in the microdarcy to nanodarcy range. When fluid (gas or water) flows in a shale pore, the molecule size is quite comparable to the flow diameter. When some gas molecules strike against the pore wall, they retain a certain velocity that causes them to “slip.” Under those conditions, Darcy’s equation may not be accurate or practical for describing the fluid-flow behavior because there may be other flow mechanisms at work such as slip flow and diffusive flow. Extensive studies have been conducted on single-phase flow in tight-sand and shale gas systems, and equations have been derived to measure the relative permeability of gas and to determine the single-phase gas-slippage effect. However, under real shale-gas-reservoir conditions, two phases (mostly water and gas) typically exist. It has been reported that in some ultralow-permeability shale-gas reservoirs, water saturation could be much greater than in conventional shale-gas plays. The effects of saturated water on gas permeability/relative permeability and gas slippage still have not been investigated sufficiently. For laboratory experiments, shale samples were used in most cases in order to represent the real pore structure and distribution in the reservoir. However, there are some limitations of using shale samples in laboratory experiments. For example, water saturation and saturation distribution are difficult to measure. Meanwhile, the laboratory-on-chip technique is becoming a suitable approach for investigating fluid flow in ultrasmall pores. Nano fluidics and microfluidics have been used in different subject areas for both fundamental research and application. Some micromodels are being used to study multiphase flow under both saturated and unsaturated conditions. Furthermore, the laboratory-on-chip technique provides a means by which to directly visualize fluid-flow behavior, such as the displacement of one fluid by another, because most micro-/nanofluidic chips are made of transparent materials. Micromodels have been used to simulate numerous porous-media-transport phenomena, including microorganism transport in unsaturated porous media. However, visualization studies of fluid flow in nanochannels are still lacking, especially for shale gas and tight gas.

Study on the effect of hot dressing with wuma plaster on prevention of phlebitis induced by injecting mannitol

Objective To observe the effect of hot dressing with wuma plaster on prevention of phlebitis induced by injecting mannitol and nursing. Methods A total of 90 cases of patients with lumbar intervertebral disc herniation received 540 intravenous infusion by 20% mannitol were randomly divided into study group( n =45 ) and control group ( n = 45 ). The study group was given hot dressing with wuma plaster 30 minute by spot of sting about 2cm along the vein and the control group was not given . Phlebitis were observed in two group .Results There were 4 ( 8.87% ) of phlebitis in study group and 15 ( 33.33% ) of phlebitis in control group.There was significant difference between two groups ( x2 = 6.67, P ＜ 0.01 ). Conclusions Hot dressing with wuma plaster can reduce the phlebitis by 20% mannitol intravenous infusion. Key words: Wuma plaster; Hot dressing; Mannitol; Phlebitis; Nursing

Neural stem cells and alcohol.

This article summarizes the proceedings of a symposium held at the 2002 Research Society on Alcoholism Meeting in San Francisco, California. The aim of this symposium was to review research on the effects of ethanol on neural stems cells and neurogenesis. Ethanol is known to alter neurogenesis during development; however, recent studies indicate that the brain forms new neurons from stem cells throughout life. Furthermore, stem cells can be transplanted into the brain, creating exciting new possibilities to study brain function. The symposium covered these research areas. Dr. Michael W. Miller reviewed knowledge on the effects of ethanol on stem cell proliferation and differentiation during development. Dr. Wu Ma described studies in culture indicating that (1) neural stem cells express functional muscarinic acetylcholine receptors (mAchR), (2) mAchR-mediated proliferation involves Ca signaling and mitogen-activated protein kinase phosphorylation, and (3) phosphoinositol-3 kinase is a downstream effector for mAchR-mediated cell proliferation via activation of Akt. Drs. Kim Nixon and Fulton T. Crews followed with in vivo studies on ethanol's effects on adult neural stem cell proliferation and differentiation. Dr. W. Michael Zawada described studies directed at dopamine neuron cell transplants into mammalian central nervous system. These studies clearly establish that ethanol has significant effects on stem cells.

Character of the O–C Variation of Four W UMa Type Stars: AW UMa, AP Leo, AG Vir and AH Vir

An analysis was carried out of the secular period variation of four WU Ma type stars (AW UMa, AP Leo, AG Vir and AH Vir) using some newly determined times of minima as well as others reported in the literature. It was found that two stars show period increases, one a period decrease and the remaining shows no variation in period.