scholarly journals Study of the Penetration and Diffusion Characteristics of Inorganic Solidified Foam in Rock Fractures

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Yi Lu ◽  
Tao Wang ◽  
Qing Ye
Keyword(s):  
Effective Diffusion ◽  
Rock Fractures ◽  
Prediction Formula ◽  
Diffusion Distance ◽  
Coal Fire ◽  
Diffusion Characteristics ◽  
Diffusion Pattern ◽  
The Right ◽  
Fluid Penetration ◽  
And Diffusion

To explore the penetration and diffusion law in coal and rock fractures when inorganic solidified foam (ISF) is used to prevent coal fire, the penetration experiment was conducted; the results showed that the penetration pressure fluctuates within a certain range and decreases with the diffusion distance. In theXYplane, the diffusion pattern presents an ellipsoid shape, and the diffusion area becomes increasingly large over time; in theXZplane, the foam fluid penetration changes from dense to loose in theXdirection and it does not undergo downward penetration and diffuses via its own weight in theZdirection; in theYZplane, it is loose on the left and dense on the right. The viscosity of ISF was tested and then the time-varying formula was fitted. The formula of the effective diffusion radius for foam fluid diffusing in the fracture channel was determined theoretically. The permeability coefficient and other related parameters were calculated in terms of the penetration pressure and diffusion time of two monitoring points. At last, the prediction formula of effective diffusion distance of foam fluid was verified with the remaining seven monitoring points and all the relative error of monitoring is within 10%.

scholarly journals Numerical Study of the Influence of Secondary Air Uniformity on Jet Penetration and Gas-Solid Diffusion Characteristics in a Large-Scale CFB Boiler

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5679
Author(s):  
Xiong Zheng ◽  
Jin Yan ◽  
Jinping Wang ◽  
Xiaofeng Lu
Keyword(s):  
Penetration Depth ◽  
Large Scale ◽  
Numerical Study ◽  
Diffusion Distance ◽  
Boiler Load ◽  
Cfb Boiler ◽  
Diffusion Characteristics ◽  
Jet Penetration ◽  
Secondary Air ◽  
And Diffusion

The uniformity of secondary air (SA) in large-scale CFB boilers has an important influence on gas-solid flow and combustion, but was seldom considered in previous studies. Numerical simulation based on the Eulerian–Eulerian and RNG k-ε turbulence models was conducted to explore the influence of SA uniformity and load variation on jet penetration, diffusion characteristics and gas-solid mixing in the first 600 MW supercritical CFB boiler. The results showed that better SA uniformity was conductive to the uniformity of SA penetration and gas-solid mixing along the furnace height, although the penetration depth and diffusion distance showed an opposite trend. In addition, the penetration depth and diffusion distance got enhanced with higher boiler load. The inner and outer SA jets could not cover the furnace width, and the uneven SA uniformity led to a huge deviation of the solid concentration within 10 m of the air distributor. Eventually, a calculation model was successfully established for predicting the penetration depth of inclined thermal SA jets during boiler operation.

Neuroimaging of Children With Takayasu Arteritis

2021 ◽  
pp. 088307382199128
Author(s):  
Hafize Emine Sönmez ◽  
Ferhat Demir ◽  
Semanur Özdel ◽  
Şerife Gül Karadağ ◽  
Esra Bağlan ◽  
...  
Keyword(s):  
Takayasu Arteritis ◽  
Internal Carotid ◽  
Laboratory Data ◽  
Left Middle Cerebral Artery ◽  
Mri Findings ◽  
Cranial Mri ◽  
Magnetic Resonance Imaging Mri ◽  
The Right ◽  
And Diffusion ◽  
Left Middle

Objective: Takayasu arteritis is a rare granulomatous chronic vasculitis that affects the aorta and its main branches. Neurologic manifestations can accompany the disease; however, there is no study on neuroimaging in children with Takayasu arteritis. Therefore, we aimed to evaluate cranial magnetic resonance imaging (MRI) in pediatric Takayasu arteritis patients. Materials and Methods: Demographic, clinical, and laboratory data were obtained retrospectively. Results: The study included 15 pediatric Takayasu arteritis patients. All patients presented with constitutional symptoms. Additionally, 6 patients suffered from headache, 2 had syncope, 1 had loss of consciousness, and 1 had convulsion. All patients underwent cranial and diffusion MRI a median 12 months after diagnosis. Cranial MRI findings were normal in 12 patients, whereas 3 patients had abnormal findings, as follows: stenosis in the M1 and M2 segments of the left middle cerebral artery (n = 1); diffuse thinning of the right internal carotid, middle cerebral, and right vertebral and basilar artery (n = 1); as a sequela, areas of focal gliosis in both the lateral ventricular and posterior periventricular regions (n = 1). Among these 3 patients, 1 had no neurologic complaints. Conclusion: Abnormal MRI findings can be observed in pediatric Takayasu arteritis patients, even those that are asymptomatic; therefore, clinicians should carefully evaluate neurologic involvement in all pediatric Takayasu arteritis patients.

Organic Heterojunctions for Photovoltaic Applications: C60 Growth on Pentacene

2010 ◽  
Vol 1263 ◽  
Author(s):  
Rebecca Ann Cantrell ◽  
Paulette Clancy
Keyword(s):  
Atomic Scale ◽  
Short Axis ◽  
Energy Functions ◽  
Potential Energy Functions ◽  
The North ◽  
Diffusion Characteristics ◽  
Static Energy ◽  
Semi Empirical ◽  
Organic Heterojunctions ◽  
And Diffusion

AbstractUsing atomic-scale Molecular Dynamics (MD) and energy minimization techniques in conjunction with semi-empirical MM3 potential energy functions, we consider the adsorption of a C60 molecule on a series of hypothetical pentacene structures that vary only in the tilt of the angle that the short axis of the pentacene molecules makes with the underlying surface (the long axis lying essentially flat, as on a metal substrate). Important relationships were discovered between the angle adopted by the short axis of pentacene on the surface, φ1, and the adsorption and diffusion characteristics of C60. Static energy calculations show that there is a transition of the deepest energy minima from between the pentacene rows at low values of φ1 to within the rows at high values of φ1, where φ1 is the angle the pentacene short axis makes with the surface. MD confirms this trend by the predominant residence locations at the extreme φ1 values. Furthermore, MD results suggest that the C60 traverses the pentacene surface in the east-west direction for lower φ1 values (φ1 ≤ 40°) and in the north-south direction for higher φ1 values (φ1 ≥ 70°). Taking both static and dynamic results together, the most favorable tilt angles for mono-directional nanowire growth should occur between 70° and 80° off-normal.

scholarly journals Experimental and Simulation Studies on Adsorption and Diffusion Characteristics of Coalbed Methane

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3445 ◽  
Author(s):  
Donghyeon Kim ◽  
Youngjin Seo ◽  
Juhyun Kim ◽  
Jeongmin Han ◽  
Youngsoo Lee
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Coalbed Methane ◽  
Equilibrium Time ◽  
Diffusion Characteristics ◽  
Adsorbed Methane ◽  
Cbm Production ◽  
Lump Coal ◽  
And Diffusion

Coalbed methane (CBM) content is generally estimated using the isotherm theory between pressure and adsorbed amounts of methane. It usually determines the maximum content of adsorbed methane or storage capacity. However, CBM content obtained via laboratory experiment is not consistent with that in the in-situ state because samples are usually ground, which changes the specific surface area. In this study, the effect of the specific surface area relative to CBM content was investigated, and diffusion coefficients were estimated using equilibrium time analysis. The differences in adsorbed content with sample particle size allowed the determination of a specific surface area where gases can adsorb. Also, there was an equilibrium time difference between fine and lump coal, because more time is needed for the gas to diffuse through the coal matrix and adsorb onto the surface in lump coal. Based on this, we constructed a laboratory-scale simulation model, which matched with experimental results. Consequently, the diffusion coefficient, which is usually calculated through canister testing, can be easily obtained. These results stress that lump coal experiments and associated simulations are necessary for more reliable CBM production analysis.

Altered microstructure integrity of the amygdala in schizophrenia: a bimodal MRI and DWI study

2010 ◽  
Vol 41 (2) ◽  
pp. 301-311 ◽  
Author(s):  
B. Tomasino ◽  
M. Bellani ◽  
C. Perlini ◽  
G. Rambaldelli ◽  
R. Cerini ◽  
...  
Keyword(s):  
Emotional Processing ◽  
Structural Magnetic Resonance Imaging ◽  
Apparent Diffusion Coefficients ◽  
Tissue Organization ◽  
Water Diffusivity ◽  
Apparent Diffusion ◽  
Magnetic Resonance Imaging Mri ◽  
The Right ◽  
And Diffusion

BackgroundThe amygdala plays a central role in the fronto-limbic network involved in the processing of emotions. Structural and functional abnormalities of the amygdala have recently been found in schizophrenia, although there are still contradictory results about its reduced or preserved volumes.MethodIn order to address these contradictory findings and to further elucidate the possibly underlying pathophysiological process of the amygdala, we employed structural magnetic resonance imaging (MRI) and diffusion weighted imaging (DWI), exploring amygdalar volume and microstructural changes in 69 patients with schizophrenia and 72 matched healthy subjects, relating these indices to psychopathological measures.ResultsMeasuring water diffusivity, the apparent diffusion coefficients (ADCs) for the right amygdala were found to be significantly greater in patients with schizophrenia compared with healthy controls, with a trend for abnormally reduced volumes. Also, significant correlations between mood symptoms and amygdalar volumes were found in schizophrenia.ConclusionsWe therefore provide evidence that schizophrenia is associated with disrupted tissue organization of the right amygdala, despite partially preserved size, which may ultimately lead to abnormal emotional processing in schizophrenia. This result confirms the major role of the amygdala in the pathophysiology of schizophrenia and is discussed with respect to amygdalar structural and functional abnormalities found in patients suffering from this illness.

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