Pore structure evolution during lignite pyrolysis based on nuclear magnetic resonance

Increasing attention is being paid to the clean and efficient mining and utilization of coal resources. Lignite is a major component of coal; however, its high moisture and volatile contents and low calorific value cause it to have low mining and utilization efficiencies. During the dehydration, upgrading and in-situ heat injection or underground coal gasification of lignite, its pore structure plays an important role in the pyrolysis and product transfer processes. Therefore, it is necessary to systematically study the high-temperature pore structure of lignite. The evolution of pore fissures in gas-pyrolyzed lignite was studied by nuclear magnetic resonance combined with a gas heating reactor and test device. We found that the total connectivity, porosity and permeability of lignite increased between temperatures of 25 °C and 250 °C, then decreased at 350 °C and increased again at 450 °C. At 450 °C, the porosity, effective porosity and permeability of lignite were 18.32%, 30.22% and 856.98 md, respectively. The evolution in the pore structure parameters of lignite with temperature was observed to determine the changes in seepage channels that occur during the processes of lignite mining and utilization

Mechanical effects on KATP channel gating in rat ventricular myocytes.

Cardiac KATP channels link metabolism with electrical activity. They are implicated in arrhythmias, secretion of atrial natriuretic peptide and protection of the heart from hypertrophy and failure. These processes may involve mechanosensitivity. KATP channels can be activated by mechanical stimulation and disrupting the cortical actin increases the activity. We propose that KATP channels are modulated by local bilayer tension and this tension is affected by cortical F-actin. Here we measured KATP background activity and stretch sensitivity with inside-out patches of rat ventricular myocytes before and after disrupting F-actin. Disrupting F-actin potentiated background activity but did not influence the slope sensitivity in the semilog relationship of NPo vs. suction that is a measure of the change in dimensions between closed and open states. Thus actin alters prestress on the channel probably by parallel elastic sharing of mean cortical tension with the bilayer

K_ATP response to suction.

<p>Current was recorded at −60 mV in symmetrical solutions at the indicated pressures. A: Two data segments of 2.8 min with 2 min of intervening data omitted to show steady state behavior. K_ATP was inhibited by 0.2 mM ATP and activated by suction. B: K_ATP response to pressure ladders. C: Traces a to e show longer term activity and are marked with corresponding letters in B. D: All-points histograms were constructed using the data segments (1.6 sec each) in B at 0, −20 and −40 mm Hg, respectively.</p

Effect of cytoB on the response to pressure steps.

<p>A: Recordings from a patch before and after cytoB treatment. B: Recordings in another patch before and after exposure to phalloidin (10 µM) followed by cytoB (20 µmol/L) (phal+cytoB). C: The semilog plots of <i>NP_o</i>-pressure relationship before and after treatment with cytoB. The two semilog plots are parallel while the intercept is increased by cytoB (n = 6; <i>P</i><0.05) suggesting cytoB increases the background activity only. D: The semilog plots of <i>NP_o</i>-pressure relationship before and after treatment with phalloidin followed by cytoB (phal+cytoB). The two semilog graphs coincides and the increment in background activity induced by cytoB was abolished by application of phalloidin in advance (n = 5; <i>P</i>>0.05).</p

Effect of thymosin-β4.

<p>A: Recordings from the same patch before (control) and after thymosin-β4 (Tβ4, 50 µg/ml) treatment. B: Recordings from another patch before (control) and then treatment with G-actin (100 µg/ml) followed by thymosin-β4 (50 µg/ml) (actin+Tβ4). C: The semilog plot of <i>NP_o</i>-pressure relationships before (control) and after treatment with thymosin-β4 (Tβ4). The two fits are parallel while the <i>NP_o</i> is increased by thymosin-β4 (n = 7; <i>P</i><0.05). D: The semilog plotting of <i>NP_o</i>-pressure relationships before (control) and after treatment with G-actin followed by thymosin-β4 (actin+Tβ4). The two semilog plots are parallel and the intercept isn’t increased by thymosin-β4 due to combined application of G-actin (n = 5; <i>P</i>>0.05).</p