ABSTRACT
At least one in five of all planetary nebulae are the product of a common envelope (CE) interaction, where the companion in-spirals into the envelope of an asymptotic giant branch (AGB) star ...ejecting the nebula and leaving behind a compact binary. In this work we carry out 3D smoothed particle hydrodynamics simulations of the CE interaction between a 1.7 M⊙ AGB star and a 0.6 M⊙ companion. We model the AGB structure using a 1D stellar model taken at the seventh thermal pulse. The interaction takes place when the giant is on the expanding phase of the seventh thermal pulse and has a radius of 250 R⊙. The post-CE orbital separations varies between 20 and 31 R⊙, with the inclusion of recombination energy resulting in wider separations. Based on the observed short in-spiral time-scales, we suggest that thermal pulses can trigger CEs, extending the ability of AGB stars to capture companions into CEs, that would lead to the prediction of a larger population of post-AGB, post-CE binaries. Simulations that include a tabulated equation of state unbind a great deal more gas, likely unbinding the entire envelope on short time-scales. The shape of the CE after the in-spiral is more spherical for AGB than red giant branch stars, and even more so if recombination energy is included. We expect that the planetary nebula formed from this CE will have different features compared to those formed from red giant branch stars.
CCS (Carbon dioxide Capture and Storage) projects have been focused on as one of state-of-art technologies to prevent the CO sub(2) emission in the atmosphere. In a project, the CO sub(2) collected ...from factories is injected into the geological reservoir at deep underground through well and stored in the reservoir. It is expected that the well will have gradual degradations due to high temperature, high pressure and high concentration CO sub(2) at deep underground. The process of the degradations should be investigated to prevent from leaking the CO sub(2) through the well. In this study, the variation of pore structure and air permeability by the carbonation of the hardened cement paste exposed to the supercritical CO sub(2) under water, salt water and sealed condition was examined focusing on the carbonation progress. The pore structure of small sample (diameter 4mm and height 4 mm) became denser at 1 day of exposure all cases because of the precipitation of CaCO sub(3) in capillary pores while the carbonation of C-S-H occurred at 7 days to make pores coarse in the case of supercritical CO sub(2) in water. It was experimentally found that the slight carbonation makes pores denser and leads to the reduction of the air permeability. The hardened cement paste using oil well cement with fly ash had denser pore structure to make permeability smaller than that using only oil well cement. It is attributed to Pozzolanic reaction of fly ash at high temperature. Thus, it was suggested that fly ash has a potential to apply to the CCS well from a view point of the prevention of CO sub(2) gas leakage.
CCS (Carbon dioxide Capture and Storage) projects have been focused on as one of state-of-art technologies to prevent the CO2 emission in the atmosphere. In a project, the CO2 collected from ...factories is injected into the geological reservoir at deep underground through well and stored in the reservoir. It is expected that the well will have gradual degradations due to high temperature, high pressure and high concentration CO2 at deep underground. The process of the degradations should be investigated to prevent from leaking the CO2 through the well. In this study, the variation of pore structure and air permeability by the carbonation of the hardened cement paste exposed to the supercritical CO2 under water, salt water and sealed condition was examined focusing on the carbonation progress. The pore structure of small sample (diameter 4mm and height 4 mm) became denser at 1 day of exposure all cases because of the precipitation of CaCO3 in capillary pores while the carbonation of C-S-H occurred at 7 days to make pores coarse in the case of supercritical CO2 in water. It was experimentally found that the slight carbonation makes pores denser and leads to the reduction of the air permeability. The hardened cement paste using oil well cement with fly ash had denser pore structure to make permeability smaller than that using only oil well cement. It is attributed to Pozzolanic reaction of fly ash at high temperature. Thus, it was suggested that fly ash has a potential to apply to the CCS well from a view point of the prevention of CO2 gas leakage.
We present an analytical model that describes the response of companion stars after being impacted by a supernova in a close binary system. This model captures key properties of the luminosity ...evolution obtained from 1D stellar evolution calculations fairly well: a high-luminosity plateau phase and a decaying tail phase. It can be used to constrain the pre-supernova binary properties from the observed photometry of the companion star several years after the explosion in a relatively simple manner. The derived binary parameters are useful in constraining the evolutionary scenario for the progenitors and the physics of binary interactions. We apply our model to some known stripped-envelope supernova companions (SN1993J, SN2001ig, SN2006jc, SN2011dh, SN2013ge). Combined with other observational constraints such as the pre-supernova progenitor photometry, we find that SN1993J and SN2011dh likely had relatively massive companions on wide orbits, while SN2006jc may have had a relatively low-mass companion on a tight orbit. This trend suggests that type IIb supernova progenitors evolved from stable mass transfer channels and type Ibc progenitors may have formed from common-envelope channels. The constraints on orbital separation helps us probe the highly uncertain common-envelope physics for massive stars, especially with multiple epochs of companion observations. We also highlight possible limitations of our model due to the assumptions made in the underlying 1D models.
Background/Aims: The safety of gastric endoscopic submucosal dissection (ESD) in users of a P2Y12 receptor antagonist (P2Y12RA) under current guidelines has not been verified.
Methods: Patients ...treated by gastric ESD at Okayama University Hospital between January 2013 and December 2020 were registered. The postoperative bleeding rates of patients (group A) who did not receive any antithrombotic drugs; patients (group B) receiving aspirin or cilostazol monotherapy; and P2Y12RA users (group C) those on including monotherapy or dual antiplatelet therapy were compared. The risk factors for post-ESD bleeding were examined in a multivariate analysis of patient background, tumor factors, and antithrombotic drug management.
Results: Ultimately, 1,036 lesions (847 patients) were enrolled. The bleeding rates of group B and C were significantly higher than that of group A (p=0.012 and p<0.001, respectively), but there was no significant difference between group B and C (p=0.11). The postoperative bleeding rate was significantly higher in dual antiplatelet therapy than in P2Y12RA monotherapy (p=0.014). In multivariate analysis, tumor diameter ≥12 mm (odds ratio OR, 4.30; 95% confidence interval CI, 1.99 to 9.31), anticoagulant use (OR, 4.03; 95% CI, 1.64 to 9.86), and P2Y12RA use (OR, 3.40; 95% CI, 1.07 to 10.70) were significant risk factors for postoperative bleeding.
Conclusions: P2Y12RA use is a risk factor for postoperative bleeding in patients who undergo ESD even if receiving drug management according to guidelines. Dual antiplatelet therapy carries a higher risk of bleeding than monotherapy. (Gut Liver 2023;17:404-411)
Background/Aims: The safety of gastric endoscopic submucosal dissection (ESD) in users of a P2Y12 receptor antagonist (P2Y12RA) under current guidelines has not been verified.
Methods: Patients ...treated by gastric ESD at Okayama University Hospital between January 2013 and December 2020 were registered. The postoperative bleeding rates of patients (group A) who did not receive any antithrombotic drugs; patients (group B) receiving aspirin or cilostazol monotherapy; and P2Y12RA users (group C) those on including monotherapy or dual antiplatelet therapy were compared. The risk factors for post-ESD bleeding were examined in a multivariate analysis of patient background, tumor factors, and antithrombotic drug management.
Results: Ultimately, 1,036 lesions (847 patients) were enrolled. The bleeding rates of group B and C were significantly higher than that of group A (p=0.012 and p<0.001, respectively), but there was no significant difference between group B and C (p=0.11). The postoperative bleeding rate was significantly higher in dual antiplatelet therapy than in P2Y12RA monotherapy (p=0.014). In multivariate analysis, tumor diameter ≥12 mm (odds ratio OR, 4.30; 95% confidence interval CI, 1.99 to 9.31), anticoagulant use (OR, 4.03; 95% CI, 1.64 to 9.86), and P2Y12RA use (OR, 3.40; 95% CI, 1.07 to 10.70) were significant risk factors for postoperative bleeding.
Conclusions: P2Y12RA use is a risk factor for postoperative bleeding in patients who undergo ESD even if receiving drug management according to guidelines. Dual antiplatelet therapy carries a higher risk of bleeding than monotherapy. (Gut Liver 2023;17:404-411)
Background/Aims: The safety of gastric endoscopic submucosal dissection (ESD) in users of a P2Y12 receptor antagonist (P2Y12RA) under current guidelines has not been verified.
Methods: Patients ...treated by gastric ESD at Okayama University Hospital between January 2013 and December 2020 were registered. The postoperative bleeding rates of patients (group A) who did not receive any antithrombotic drugs; patients (group B) receiving aspirin or cilostazol monotherapy; and P2Y12RA users (group C) those on including monotherapy or dual antiplatelet therapy were compared. The risk factors for post-ESD bleeding were examined in a multivariate analysis of patient background, tumor factors, and antithrombotic drug management.
Results: Ultimately, 1,036 lesions (847 patients) were enrolled. The bleeding rates of group B and C were significantly higher than that of group A (p=0.012 and p<0.001, respectively), but there was no significant difference between group B and C (p=0.11). The postoperative bleeding rate was significantly higher in dual antiplatelet therapy than in P2Y12RA monotherapy (p=0.014). In multivariate analysis, tumor diameter ≥12 mm (odds ratio OR, 4.30; 95% confidence interval CI, 1.99 to 9.31), anticoagulant use (OR, 4.03; 95% CI, 1.64 to 9.86), and P2Y12RA use (OR, 3.40; 95% CI, 1.07 to 10.70) were significant risk factors for postoperative bleeding.
Conclusions: P2Y12RA use is a risk factor for postoperative bleeding in patients who undergo ESD even if receiving drug management according to guidelines. Dual antiplatelet therapy carries a higher risk of bleeding than monotherapy. (Gut Liver 2023;17:404-411)
PDF
