Case Study of Ambient Pressure Effects on Pore Shape in Solid

2017 ◽  
Vol 31 (4) ◽  
pp. 796-804 ◽  
Author(s):  
Shih-Yen Hsiao ◽  
Peng-Sheng Wei
Keyword(s):  
Ambient Pressure ◽  
Pressure Effects ◽  
Pore Shape

scholarly journals Durability of Stone Cladding in Buildings: A Case Study of Marble Slabs Affected by Bowing

Buildings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 229 ◽  
Author(s):  
Sousa ◽  
Sousa
Keyword(s):  
Element Model ◽  
Pressure Effects ◽  
Wind Pressure ◽  
Stability Evaluation ◽  
Building Facade ◽  
Building Facades ◽  
Anchoring Strength ◽  
Wind Pressures ◽  
Loss Of Strength

Bowing is an uncommon pathology that can affect marble stone cladding of building façades, causing a large permanent deflection and the degradation of the flexural and anchoring strength of the stone slabs, which can lead to the cladding falling from the façades. Moreover, the combination of bowing with wind pressure effects on the building façades can increase the risk of fracture and collapse of the stone slabs, especially if this combination is not properly evaluated during design. Motivated by a case study, this work describes a stability evaluation of a 15-year-old building façade coated with marble stone cladding affected by bowing and subjected to wind pressures. This evaluation was focused on the stone slabs, and was performed through finite element model (FEM) numerical simulations of these slabs submitted to wind pressures and through lab tests using samples of stone slabs removed from the building façade. The results obtained demonstrated stability problems on the stone slabs caused by wind pressure-induced stresses combined with the loss of strength due to aging and bowing effects, especially for slabs with larger dimensions.

Subsea Rigid Jumper Design Optimization for Sour Service Application

2019 ◽  
Author(s):  
Benjamin Toleman ◽  
Chaojun Huang ◽  
Mahesh Sonawane ◽  
Rohit Shankaran ◽  
Danny Foster
Keyword(s):  
Cross Flow ◽  
Pressure Effects ◽  
Fatigue Design ◽  
Trade Offs ◽  
Physical Limitations ◽  
Service Application ◽  
Viv Suppression ◽  
Design Options ◽  
Sour Service

Abstract Subsea rigid jumpers are designed to meet numerous criteria including thermal and pressure effects, environmental and riser / pipeline interaction loads, slugging, and other field specific requirements. Jumper VIV can be a concern in fields with strong bottom currents. Without the benefit of detailed VIV fatigue analysis, designers must rely on experience and engineering judgement on placement of strakes if VIV is identified as a concern. VIV mitigation is even more challenging because the jumpers can contain numerous long and short design options to accommodate tolerances for subsea well locations and installation tolerances of subsea PLETS and manifolds. This paper will discuss a case study on optimization of 12 M-shaped jumpers designed for a sour service application in Gulf of Mexico. VIV fatigue assessment of the preliminary jumper design and the methodology adopted to optimize the jumper design and placement of VIV suppression will be discussed. Challenges in meeting high target fatigue life due to sour service application will be discussed. The key challenges whilst optimizing an acceptable VIV suppression solution are the assumed effectiveness of strakes, cost / available inventory of strakes, and physical limitations for placement of strakes. This paper will highlight the trade-offs that are required to strike a balance between strength and fatigue design requirements when using straked buoyancy modules vs. regular strakes. The paper will also highlight the current limitations in design code that relies on standards developed for pipeline application. An alternative method / modification to the DNV F105 approach used to calculate the cross-flow induced in-line VIV fatigue damage is also discussed.

An estimation of modelling parameters for condensed multi-component fuels

2011 ◽  
Vol 225 (5) ◽  
pp. 1229-1235
Author(s):  
V Raghavan ◽  
W T James ◽  
A S Rangwala
Keyword(s):  
Physical Properties ◽  
Ambient Pressure ◽  
Kinetics Parameters ◽  
Pyrolysis Products ◽  
Exponential Factor ◽  
Step Procedure ◽  
Global Reaction ◽  
Thermo Physical Properties ◽  
Pyrolysis Gases

A case study to evaluate the thermo-physical properties and chemical kinetics parameters, which are employed to model the gas-phase combustion taking place over the surface of a condensed fuel, has been presented. This procedure relies on accurate experimental measurements of gaseous pyrolysis products. The pyrolysis gases can be treated as a virtual fuel, namely C xH yO z, where x, y, and z are estimated by performing atom balances for C, H, and O atoms in all the pyrolysis species. Thermo-physical properties of this virtual fuel are calculated based on the temperature and species concentration of the pyrolysis mixture. Similarly, based on the rate constant values of the reactant species present in the pyrolysis mixture, Arrhenius parameters such as pre-exponential factor and activation energy have been calculated. Polymethylmethacrylate (PMMA) is used as an example fuel in this study, and a step-by-step procedure for the estimation of the thermo-physical properties and global reaction kinetics parameters of PMMA at low to moderate ambient pressure environment is presented. In general, the technique discussed here can be applied to any condensed fuel. Following the procedure reported in this study, modelling parameters can be evaluated for complex fuels.

scholarly journals Switching deformation mode and mechanisms during subduction of continental crust: a case study from Alpine Corsica

Solid Earth ◽  
2017 ◽  
Vol 8 (4) ◽  
pp. 767-788 ◽  
Author(s):  
Giancarlo Molli ◽  
Luca Menegon ◽  
Alessandro Malasoma
Keyword(s):  
Shear Zone ◽  
Continental Crust ◽  
Ambient Pressure ◽  
Deformation Mode ◽  
Shear Zones ◽  
Small Scale ◽  
Low Grade ◽  
Stick Slip ◽  
Brittle Ductile Transition

Abstract. The switching in deformation mode (from distributed to localized) and mechanisms (viscous versus frictional) represent a relevant issue in the frame of crustal deformation, being also connected with the concept of the brittle–ductile transition and seismogenesis. In a subduction environment, switching in deformation mode and mechanisms and scale of localization may be inferred along the subduction interface, in a transition zone between the highly coupled (seismogenic zone) and decoupled deeper aseismic domain (stable slip). However, the role of brittle precursors in nucleating crystal-plastic shear zones has received more and more consideration being now recognized as fundamental in some cases for the localization of deformation and shear zone development, thus representing a case in which switching deformation mechanisms and scale and style of localization (deformation mode) interact and relate to each other. This contribution analyses an example of a millimetre-scale shear zone localized by brittle precursor formed within a host granitic protomylonite. The studied structures, developed in ambient pressure–temperature (P–T) conditions of low-grade blueschist facies (temperature T of ca. 300 °C and pressure P ≥ 0. 70 GPa) during involvement of Corsican continental crust in the Alpine subduction. We used a multidisciplinary approach by combining detailed microstructural and petrographic analyses, crystallographic preferred orientation by electron backscatter diffraction (EBSD), and palaeopiezometric studies on a selected sample to support an evolutionary model and deformation path for subducted continental crust. We infer that the studied structures, possibly formed by transient instability associated with fluctuations of pore fluid pressure and episodic strain rate variations, may be considered as a small-scale example of fault behaviour associated with a cycle of interseismic creep and coseismic rupture or a new analogue for episodic tremors and slow-slip structures. Our case study represents, therefore, a fossil example of association of fault structures related to stick-slip strain accommodation during subduction of continental crust.

Thermal and Flow Fields Modeling of Fast Spark Discharges in Air

2006 ◽  
Vol 129 (1) ◽  
pp. 55-65 ◽  
Author(s):  
O. Ekici ◽  
O. A. Ezekoye ◽  
M. J. Hall ◽  
R. D. Matthews
Keyword(s):  
Ambient Pressure ◽  
Early Time ◽  
Spark Discharge ◽  
Pressure Effects ◽  
Local Thermal Equilibrium ◽  
Heat Conducting ◽  
Current Profile ◽  
Spark Plug ◽  
Time Flow ◽  
History Of

In this study, a two-dimensional axisymmetric computational model of spark discharge in air is presented to provide a better understanding of the dynamics of the process. Better understanding of the modeling issues in spark discharge processes is an important issue for the automotive spark plug community. In this work we investigate the evolution of the shock front, temperature, pressure, density, geometry, and flow history of a plasma kernel using various assumptions that are typically used in spark discharge simulations. A continuum, inviscid, heat conducting, single fluid description of the flow is considered with radiative losses. Assuming local thermal equilibrium, the energy input due to resistive heating is determined using a specified current profile and temperature-dependent gas electrical conductivity in the gap. The spark discharge model focuses on the early time flow physics, the relative importance of conduction and radiation losses, the influence of thermodynamic model choice and ambient pressure effects.

Exploring the Suitability of Polymer Injection in the Niger Delta Sands Using 3-D Simulation and Experimental Analysis - A Case Study-Paper ID 28

2021 ◽  
Author(s):  
Linda Dennar ◽  
Mohammed Amro ◽  
Nicolai-Alexeji Kummer ◽  
Elias Arochukwu ◽  
Ahmed Suleiman ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Niger Delta ◽  
Life Stage ◽  
Pressure Effects ◽  
Experimental Result ◽  
Experimental Investigations ◽  
Field Development ◽  
Study Results

Abstract Enhanced oil recovery has been gaining relevance over the years following success stories from already executed projects from various parts of the globe. The recoveries from such successful projects have tremendously increased the terminal life cycle recoveries from the subject reservoirs and subsequently the project Net Present Value and Value to Investment Ratio. More than 90% of Field Development Plans in the Niger Delta have not considered Enhanced Recovery Mechanism as part of the field development options and as such Top Quartile Recovery Factors are never achieved. In this study, the effectiveness of Enhanced Oil Recovery within the Niger-Delta reservoir sands via 3-Dimentional Dynamic Simulation, Economic models and Experimental investigations (temperature and pressure effects on polymer effectiveness) was done. The GN7000 reservoir was used as a case study for this work. This reservoir is the largest gas cap reservoir in the N-Onshore field within the Niger Delta area and it is at the mid-life stage. This study tested the effectiveness of three Recovery mechanisms (Water Flood, Polymer Flood and Polymer Alternating Gas). Simulated and Experimental result suggests that Polymer flooding and Polymer Alternating Gas (PAG) yields greater Technical Ultimate Recovery, better economic indices but greater complexity in polymer selection due to inherent high reservoir temperature and low salinity that make the use of synthetic polymers inadequate. Experimental investigation showed that biopolymers are most suitable for this sand. The suitability of some biopolymers (Xanthan and copolymers containing high level of 2-acrylamido2-methyl propane sulfonate (AMPS) showed good results. Study results shows that with the deployment of biopolymers with high viscosifying power and high resistance to thermal degradation an incremental recovery of 8% from the natural flow could be achieved. Research findings indicate that biopolymers could yield good results for Niger Delta sands within the pressure and temperature ranges of 93°C and 290 Bar.

Ambient Pressure Effects on Atmospheric Oxygen Levels in Patrol Submarines

1977 ◽  
Vol 63 (2) ◽  
pp. 101-104
Author(s):  
E. J. Jolly
Keyword(s):  
Atmospheric Oxygen ◽  
Ambient Pressure ◽  
Pressure Effects ◽  
Oxygen Generation ◽  
Oxygen Levels

AbstractThis article describes a submarine trial which demonstrates the importance of considering ambient pressure in a diesel-electric submarine when determining submerged time allowed before commencing oxygen generation.

Predictive Accuracy of Wideband Absorbance at Ambient and Tympanometric Peak Pressure Conditions in Identifying Children with Surgically Confirmed Otitis Media with Effusion

2020 ◽  
Author(s):  
Venkatesh Aithal ◽  
Sreedevi Aithal ◽  
Joseph Kei ◽  
Shane Anderson ◽  
David Wright
Keyword(s):  
Otitis Media ◽  
Middle Ear ◽  
Peak Pressure ◽  
Predictive Accuracy ◽  
Otitis Media With Effusion ◽  
Ambient Pressure ◽  
Pressure Effects ◽  
Healthy Children ◽  
Operating Characteristics ◽  
Middle Ear Pressure

Background: Wideband absorbance (WBA) measured at ambient pressure (WBAA) does not directly accountfor middle ear pressure effects. On the other hand, WBA measured at tympanometric peak pressure(TPP) (WBATPP) may compensate for the middle ear pressure effects. To date, there are no studies thathave compared WBAA and WBATPP in ears with surgically confirmed otitis media with effusion (OME).<br />Purpose: The purpose of this study was to compare the predictive accuracy of WBAA and WBATPP inears with OME.<br />Research Design: Prospective cross-sectional study.<br />Study Sample: A total of 60 ears from 38 healthy children (mean age = 6.5 years, SD = 1.84 years) and60 ears from 38 children (mean age = 5.5 years, SD = 3.3 years) with confirmed OME during myringotomywere included in this study.<br />Data Collection and Analysis: Results were analyzed using descriptive statistics and analysis of variance.The predictive accuracy of WBAA and WBATPP was determined using receiver operating characteristics(ROC) analyses.<br />Results: Both WBAA and WBATPP were reduced in ears with OME compared with that in healthy ears.The area under the ROC (AROC) curve was 0.92 for WBAA at 1.5 kHz, whereas that for WBATPP at 1.25kHz was 0.91. In comparison, the AROC for 226-Hz tympanometry based on the static acoustic admittance(Ytm) measure was 0.93.<br />Conclusions: Both WBAA and WBATPP showed high and similar test performance, but neither test performedsignificantly better than 226-Hz tympanometry for detection of surgically confirmed OME.<br />

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