Magmatic systems are the engines driving volcanic eruptions and the source of fluids responsible for the formation of porphyry-type ore deposits. Sudden variations of pressure, temperature and volume ...in magmatic systems can produce unrest, which may culminate in a volcanic eruption and/or the abrupt release of ore-forming fluids. Such variations of the conditions within magmatic systems are commonly ascribed to the injection of new magma from depth. However, as magmas fractionating at depth or rising to the upper crust release CO2-rich fluids, the interaction between carbonic fluids and H2O-rich magmas stored in the upper crust (CO2 flushing), must also be a common process affecting the evolution of subvolcanic magma reservoirs. Here, we investigate the effect of gas injection on the stability and chemical evolution of magmatic systems.
We calculate the chemical and physical evolution of magmas subjected to CO2-flushing using rhyolite-MELTS. We compare the calculations with a set of melt inclusion data for Mt. St. Helens, Merapi, Etna, and Stromboli volcanoes. We provide an approach that can be used to distinguish between melt inclusions trapped during CO2 flushing, magma ascent and decompression, or those affected by post-entrapment H2O-loss. Our results show that CO2 flushing is a widespread process in both felsic and mafic magmatic systems. Depending upon initial magma crystallinity and duration of CO2 input, flushing can either lead to volcanic eruption or fluid release. We suggest that CO2 flushing is a fundamental process modulating the behaviour and chemical evolution of crustal magmatic systems.
•New method to identify magmatic processes from chemistry of melt inclusions.•CO2 flushing is a common process both in mafic and felsic systems.•CO2 flushing can lead to volcanic eruptions or the release of magmatic fluids.
Flushing and erythema are frequent skin symptoms in rosacea. Because their adequate treatment remains a clinical challenge, new treatment options are explored, such as oral β-blockers.
To evaluate ...the efficacy of oral β-blockers for rosacea-associated facial flushing and erythema.
PubMed, Embase, Web of Science, and Cochrane Library were systematically searched, including studies providing original data on the efficacy of oral β-blockers in rosacea patients with facial flushing and/or persistent erythema. Risk of bias was assessed using the Cochrane Risk of Bias tool, Newcastle-Ottawa scale, and Quality in Prognosis Studies tool.
Nine studies evaluating the use of carvedilol, propranolol, nadolol, and β-blockers in general were included. Articles studying carvedilol and propranolol showed a large reduction of erythema and flushing during treatment with a rapid onset of symptom control. Bradycardia and hypotension were the most commonly described adverse events.
Most studies had a retrospective design with a small sample size, and outcome measurement was often subjective.
Oral β-blockers could be an effective treatment option for patients with rosacea with facial erythema and flushing that does not respond to conventional therapy. Larger prospective trials with objective outcome assessment are needed to validate the promising results of these studies.
The flushing phenomenon may represent a physiologic or a pathologic reaction. Although flushing is usually benign, it is prudent that the physician remains aware of potentially life-threatening ...conditions associated with cutaneous flushing. A thorough investigation should be performed if the flushing is atypical or not clearly associated with a benign underlying process. The diagnosis often relies on a pertinent history, review of systems, physical examination, and various laboratory and imaging modalities, all of which are discussed in the 2 articles in this continuing medical education series. This article reviews flushing associated with fever, hyperthermia, emotions, menopause, medications, alcohol, food, hypersensitivity reactions, rosacea, hyperthyroidism, dumping syndrome, superior vena cava syndrome, and neurologic etiologies.
Cosolvent flushing has evolved as a viable technology for the remediation of groundwater resources contaminated with non‐aqueous phase liquids (NAPLs). This study investigates the effect of ...cosolvents on the interphase mass transfer of NAPLs into the flushing solutions, a key process that controls the effectiveness of the enhanced dissolution technology. A series of laboratory‐scale flow cell experiments were conducted to test the effect of cosolvent content, mean grain diameter and flushing velocity on the interphase mass transfer of NAPLs present in saturated porous media pooled form. The cosolvent and NAPL selected for this purpose are ethanol and 1,2‐dichlorobenzene, respectively. The experimental results are interpreted using a two‐dimensional numerical model and validated with a one‐dimensional analytical solution. The best fit mass transfer coefficients estimated from the model are used to develop Sherwood correlations expressed in terms of the Peclet and Schmidt numbers and the porous media main grain diameter. It is observed that the presence of the cosolvent can have an important impact on the interphase mass transfer coefficient. Specifically, the Sherwood correlation is found to be inversely proportional to the Schmidt number, expressed as a function of the viscosity and density of the cosolvent flushing solution. The developed Sherwood correlations can potentially be used in modeling studies and field applications involving the enhanced dissolution of entrapped NAPLs.
Key Points
Flushing experiments were performed to assess impact of cosolvent content on interphase mass transfer from pooled non‐aqueous phase liquids in porous media
Flushing solution content, expressed in terms of the Schmidt number, strongly influences interphase mass transfer coefficient
Sherwood correlations, expressed as a function of the Schmidt number and the Peclet number, are developed
The effect of a plate installation upstream of an orifice was investigated as a new method for improving the pressurized flushing efficiency. A plate with three different widths (B
T
) was installed ...at four different distances (L
T
) upstream of the orifice. According to the results, the plate installation significantly increased the pressurized flushing efficiency due to the wake vortices formed upstream of the orifice. The flushing efficiency increased up to a maximum value of 11.5 times relative to what was calculated for the experiment without plate for the same conditions. For the best configuration of the plate width and its distance from the outlet (i.e., L
T
/D
O
= 0.7 and B
T
/D
O
= 0.5, D
O
is the orifice diameter), the length, width, and depth of the flushing cone increased by approximately 160, 90, and 240% relative to the control experiment under the same conditions, respectively. Four empirical equations based on the effective and dimensionless variables were developed, enabling the users to make predictions based on the flushing cone volume and dimensions. Finally, the importance of each effective parameter in the derived equations were analyzed using sensitivity analysis method. The sensitivity analysis results showed the greater impact of outlet discharge of the orifice and the plate distance than its width on the flushing cone volume and dimensions.
Depressive disorder (DD) affects approximately 20 % of adolescents worldwide, but it is underdiagnosed due to the lack of objective biomarkers. Niacin skin flushing response (NSFR) is an objective ...and noninvasive biomarker of adult depression; however, its effectiveness has not been assessed in adolescents.
This study included 198 adolescents with 50 % healthy controls (HC). Linear mixed-effects model and multiple linear regression analyses were performed to assess differences in NSFR between the DD and HC groups. Logistic regression models based on NSFR were constructed, and the area under curve (AUC) was calculated to evaluate the performance of models. Spearman correlations were calculated to assess the relationships between NSFR and disease duration and hormone levels associated with puberty.
Adolescents with DD displayed significantly attenuated and delayed NSFR compared to HC. NSFR effectively distinguished DD patients from HC with AUC values of 0.719 (sensitivity = 0.844) and 0.721 (sensitivity = 0.829) determined in the discovery and validation sets, respectively. Within the DD group, the maximum degree of NSFR was negatively correlated with the disease duration (r = −0.28, p = 0.011), and the overall degree of NSFR was positively associated with prolactin (r = 0.29, p = 0.039) and thyroxine (r = 0.29, p = 0.027) levels.
Future investigations will be necessary to confirm our results in an independent sample set.
This study provides the first evidence of the utility of NSFR as an objective auxiliary diagnostic biomarker for adolescent depression. It provides new clues to understand the pathophysiology of the disease, and helps promote precise diagnosis, treatment, and prognostic evaluation of adolescent depression.
•A relatively large cohort of adolescents with or without depression was used.•Niacin skin flushing response (NSFR) was attenuated and delayed in patients.•Diagnostic model based on NSFR showed fair predictive power in two sample sets.•NSFR was positively associated with thyroxine and prolactin levels in patients.•Our results supported the value of NSFR as a biomarker for adolescent depression.
A set of orthogonal experiments using three factors (flushing pressure, flushing frequency, and flushing time) was used to study the anti-clogging performance of a patch-type dentation ...labyrinth-channel emitter. After irrigation, the change in the emitter discharge was tested, and the discharged particle size distribution was measured using a laser particle size analyser. The results showed that the flushing treatments had a significant effect on the anti-clogging performance of the emitter and extended the emitter's service life by 35.2% on average. Among the three factors, the flushing pressure lengthened the emitter's service life most. With more irrigation events, the discharged particle sizes V10, V50, and V90 (i.e. the particle size with accumulating particle volumes of 10%, 50% and 90%, respectively) decreased under different flushing treatments. However, particle sizes were still larger than those without the flushing. Particles of all sizes could be trapped in the emitter channel. However, coarse particles were trapped more easily, which was the major reason for emitter clogging. Flushing treatments helped the discharge of sediments. The analysis of variance indicated that the flushing pressure had a significant effect on the discharge of coarse particles and flushing time had an obvious impact on fine particles. Elevating the flushing pressure was the major method to extend the life of emitters for water with large particles >18.04 μm diameter and extending the flushing time was the main way for water with particles <1.20 μm diameter.
•Measures taken increased the average service life of emitter by 35.1%.•Particle size of discharged sand particles after flushing is larger.•Flushing pressure has a significant effect on coarse sand particles and service life.•Flushing time has a positive effect on fine sand particle removal.
Soft coal seams are characterized by high gas content, high tectonic stress, low strength, and low permeability; thus, gas extraction from soft coal seams is rather difficult, and outburst accidents ...commonly occur in their driving face. To enhance gas extraction and thus prevent outburst disasters, a novel in-seam borehole discontinuous hydraulic flushing (ISBDHF) technology was proposed in this work. By adopting a multiphysical coupling model and a new FLAC
3D
and COMSOL Multiphysics combined numerical solving method, we first analyzed the enhanced gas extraction mechanism of hydraulic flushing using the numerical simulation method. After that, this new technology was applied in the Xinjing coal mine, and its application results were systematically investigated. The numerical simulation results showed that the generation of new fractures in the plastic failure zone caused by hydraulic flushing could not only increase the coal permeability by 2–3 orders of magnitude, but also decrease its gas sorption time from 1 day to several minutes due to the decrease in matrix size. Therefore, hydraulic flushing enhances gas extraction by the combined effect of increasing permeability and increasing diffusion. Moreover, nearby flushing cavities may interact with each other under multicavity conditions, further improving the permeability-increasing and diffusion-increasing effects. After adopting ISBDHF technology in the Xinjing coal mine, the borehole number and gas extraction period in the driving face decreased by 73.5 and 77.8%, respectively, while the gas extraction rate increased from 28.20 to 34.35%, which improved the coal roadway excavation speed by 1.37 times.
Coal seam gas is a kind of precious energy, but it also will be a terrible disaster in coal mining if not well controlled. Underground coal seam gas drainage is one of the most effective methods for ...lowering the risk of gas disaster. However, it is difficult to extract gas in many coal seams with low permeability, especially in tectonic coal seams, which were severely crushed or even pulverized by tectonism. The key to improving the gas drainage efficiency is stress relief and permeability increase. There are many conventional technologies to improve the gas drainage efficiency of a single coal seam, but they are inoperative on the special thick coal seam with a soft mylonitic tectonic coal sub-layer at the lower part. In this paper, to enhance gas drainage in this coal seam, we presented a hydraulic flushing gas drainage technology. Numerical simulation was conducted to analyze the stress evolution, plastic damage, permeability changes and gas drainage of the coal after hydraulic flushing. Further, abundant field experiments were carried out to investigate and verify the mechanism of stress relief and permeability increase. The results show that, after adopting the hydraulic flushing gas drainage technology, more tectonic coal in the thick coal seam was flushed out and the big hole in the tectonic coal sub-layer enlarged the range of stress relief and permeability increase, and the gas drainage efficiency increased significantly.
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