Full-Bore Pipeline Rupture as ‘Transient Fanno’ Flow

2016 ◽  
Author(s):  
Ajit Godbole ◽  
Guillaume Michal ◽  
Cheng Lu ◽  
Philip Venton ◽  
Philip Colvin
Keyword(s):  
Friction Factor ◽  
Transient Flow ◽  
Pipe Wall ◽  
Model Development ◽  
One Dimensional ◽  
A Value ◽  
Decompression Wave ◽  
Coefficient Of Viscosity ◽  
Theory And Experiment

Full-bore decompression of an initially highly pressurized pipe has been studied extensively in recent years. The main aim of this effort has been to estimate the speed of the decompression wave and its relationship to the speed of a travelling fracture in the pipe wall. It has been demonstrated that the speed of the decompression wave is influenced by the friction at the gas-solid interface, and also by the pipe size (diameter). The numerical value of the friction factor has been traditionally estimated using known relationships such as the Haaland formula. However, it has also been noticed that the friction factor calculated in this way has to be increased many-fold to achieve agreement between theory and experiment. To date, there is no physical justification for this increase. The present paper proposes an explanation by modelling the full-bore decompression as a ‘transient Fanno’ flow. The model development is based on the observation that the flow at the exit plane always tends to approach a ‘choked’ condition (sonic velocity). It is shown that a re-interpretation of the Fanno flow formula allows an estimation of the irreversibility, and therefore the friction factor, in the evolving flow. When averaged over space and time, the friction factor attains a value that need not be artificially adjusted. This value of the friction factor can be used in one-dimensional models of the decompression process. Also, the role of the ‘second coefficient of viscosity’ during the initial instants of the highly transient flow is examined.

Static and energy dependent nucleus–nucleus potential for description of near and sub-barrier fusion data

2015 ◽  
Vol 93 (11) ◽  
pp. 1343-1351 ◽  
Author(s):  
Manjeet Singh Gautam
Keyword(s):  
Degrees Of Freedom ◽  
Saxon Potential ◽  
Model Calculations ◽  
One Dimensional ◽  
A Value ◽  
Fusion Data ◽  
The One ◽  
Energy Dependent ◽  
Coupled Channel

This article analyzes the validity of static Woods–Saxon potential and the energy-dependent Woods–Saxon potential (EDWSP) to explore the specific features of fusion dynamics of [Formula: see text] and [Formula: see text] systems. The intrinsic degrees of freedom, such as inelastic surface excitations, play a crucial role in the enhancement of sub-barrier fusion excitation functions over the expectations of the one-dimensional barrier penetration model. Role of dominant intrinsic degrees of freedom of collision partners are entertained within the context of coupled channel calculations. Furthermore, the one-dimensional Wong formula using static Woods–Saxon potential fails miserably to describe the fusion enhancement of [Formula: see text] and [Formula: see text] systems. However, the Wong formula along with the EDWSP model accurately explains the observed fusion enhancement of [Formula: see text] reactions. In the fusion of [Formula: see text] reaction, the above-barrier fusion data are suppressed by a factor of 0.66 with reference to the EDWSP model calculations while the below-barrier fusion data are adequately addressed by the EDWSP model and the coupled channel calculations. Therefore, the coupled channel calculations and the EDWSP model calculations reasonably describe the observed fusion mechanism of [Formula: see text] and [Formula: see text] reactions. This suggests that the energy dependence in the Woods–Saxon potential model introduces similar kinds of barrier modification effects (barrier height, barrier position, and barrier curvature) as reflected from the coupled channel calculations. In the EDWSP model calculations, significantly larger values of diffuseness ranging from a = 0.86 to 0.94 fm, which is much larger than a value extracted from the elastic scattering analysis, are needed to address the sub-barrier fusion data.

scholarly journals Investigation of the Effects of Pipe Wall Roughness and Pipe Diameter on the Decompression Wave Speed in Natural Gas Pipelines

2012 ◽  
Author(s):  
C. Lu ◽  
G. Michal ◽  
A. Elshahomi ◽  
A. Godbole ◽  
P. Venton ◽  
...  
Keyword(s):  
Wave Speed ◽  
Pipe Wall ◽  
Experimental Results ◽  
Pipe Diameter ◽  
Wall Roughness ◽  
One Dimensional ◽  
Natural Gas Pipelines ◽  
Decompression Wave ◽  
Dynamic Simulation Model ◽  
Smooth Pipe

The shock tube experimental results have shown clearly that the decompression wave was slowed down in a pipe with a rough inner surface relative to that in a smooth pipe under comparable conditions. In the present paper a one-dimensional dynamic simulation model, named EPDECOM, was developed to investigate the effects of pipe wall roughness and pipe diameter on the decompression wave speed. Comparison with experimental results showed that the inclusion of frictional effects led to a better prediction than that of the widely used model implemented in GASDECOM. EPDECOM simulation results showed that the effect of roughness on the decompression wave speed is significant for pipe diameters less than 250 mm. However the decompression wave speed is nearly independent of the roughness for diameters above 250 mm as the frictional effect becomes negligible at such diameters.

Endangered Butterflies and their Non-Native Host Plants: Examining Shifting Values of Belonging in Restoration

2019 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Robert M. Anderson ◽  
Amy M. Lambert
Keyword(s):  
Ecological Restoration ◽  
Native Species ◽  
Puget Sound ◽  
A Value ◽  
The Social ◽  
Remote Island ◽  
Scientific Truth ◽  
Native Host

The island marble butterfly (Euchloe ausonides insulanus), thought to be extinct throughout the 20th century until re-discovered on a single remote island in Puget Sound in 1998, has become the focus of a concerted protection effort to prevent its extinction. However, efforts to “restore” island marble habitat conflict with efforts to “restore” the prairie ecosystem where it lives, because of the butterfly’s use of a non-native “weedy” host plant. Through a case study of the island marble project, we examine the practice of ecological restoration as the enactment of particular norms that define which species are understood to belong in the place being restored. We contextualize this case study within ongoing debates over the value of “native” species, indicative of deep-seated uncertainties and anxieties about the role of human intervention to alter or manage landscapes and ecosystems, in the time commonly described as the “Anthropocene.” We interpret the question of “what plants and animals belong in a particular place?” as not a question of scientific truth, but a value-laden construct of environmental management in practice, and we argue for deeper reflexivity on the part of environmental scientists and managers about the social values that inform ecological restoration.

Perempuan dan Liminalitas dalam Tradisi Perkawinan Adat di Timor Tengah Selatan

2020 ◽  
Vol 6 (1) ◽  
pp. 114
Author(s):  
Marsel Eliaser Liunokas
Keyword(s):  
Qualitative Research ◽  
Research Method ◽  
Literature Study ◽  
Qualitative Research Method ◽  
South Central ◽  
A Value ◽  
Traditional Marriage ◽  
The Village ◽  
As If

Timorese culture is patriarchal in that men are more dominant than women. As if women were not considered in traditional rituals so that an understanding was built that valued women lower than men. However, in contrast to the article to be studied, this would like to see the priority of women’s roles in traditional marriages in Belle village, South Central Timor. The role of women wiil be seen from giving awards to their parents called puah mnasi manu mnasi. This paper aims to look at the meaning of the rituals of puah mnasi maun mnasi and the role and strengths that women have in traditional marriage rituals in the village of Belle, South Central Timor. The method used for this research is a qualitative research method using interview techniques with a number of people in the Belle Villa community and literature study to strengthen this writing. Based on the data obtained this paper shows that the adat rituals of puah mnasi manu mnasi provide a value that can be learned, namely respect for women, togetherness between the two families, and brotherhood that is intertwined due to customary marital affrairs.

Adiabatic large polarons in anisotropic molecular crystals

2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj
Keyword(s):  
Energy Transfer ◽  
Effective Mass ◽  
Molecular Crystals ◽  
Single Chain ◽  
Proper Understanding ◽  
One Dimensional ◽  
Interchain Coupling ◽  
Large Polaron ◽  
The One

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.

Influence of social networks on business processes’ development

2020 ◽  
Vol 19 (12) ◽  
pp. 2225-2252
Author(s):  
E.V. Popov ◽  
V.L. Simonova ◽  
O.V. Komarova ◽  
S.S. Kaigorodova
Keyword(s):  
Social Networks ◽  
Social Media ◽  
Business Models ◽  
Business Processes ◽  
Digital Economy ◽  
Theoretical Understanding ◽  
Sales Channels ◽  
A Value ◽  
The Impact

Subject. The emergence of new ways of interaction between sellers and buyers, the formation of new sales channels and product promotion based on the use of digital economy tools is at the heart of improving the business processes. Social networks became a tool for development; their rapid growth necessitates theoretical understanding and identification of potential application in enterprise's business process digitalization. Objectives. We explore the role of social media in the digitalization of business processes, systematize the impact of social networks on business processes of enterprises in the digital economy. Methods. The theoretical and methodological analysis of social networks as a tool for digitalization of company's business processes rests on the content analysis of domestic and foreign scientific studies, comparison, generalization and systematization. Results. We highlight the key effects of the impact of social networks on the business processes of the company; show that the digitalization of business processes should be considered in the context of a value-based approach, aimed at creating a value through the algorithmization of company operations. We determine that social networks are one of the most important tools for digitalization of company's business processes, as they have a high organizational and management potential. We also systematize the effects of social media on company's business processes. Conclusions. We present theoretical provisions of the impact of social networks on business processes of enterprises, which will enable to model and organize ideas about the development of digital ecosystems and the formation of business models.

Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Stochastic Model of Non-Isothermal Flow Chemical Reactor

1996 ◽  
Vol 61 (2) ◽  
pp. 242-258 ◽  
Author(s):  
Vladimír Kudrna ◽  
Libor Vejmola ◽  
Pavel Hasal
Keyword(s):  
Stochastic Model ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Dispersion Model ◽  
Chemical Reactor ◽  
Segregation Index ◽  
One Dimensional ◽  
A Value ◽  
Isothermal Case ◽  
Flow Through

Recently developed stochastic model of a one-dimensional flow-through chemical reactor is extended in this paper also to the non-isothermal case. The model enables the evaluation of concentration and temperature profiles along the reactor. The results are compared with the commonly used one-dimensional dispersion model with Danckwerts' boundary conditions. The stochastic model also enables to evaluate a value of the segregation index.

scholarly journals Determining the Role of Acidity, Fate and Formation of IEPOX-Derived SOA in CMAQ

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 707
Author(s):  
Petros Vasilakos ◽  
Yongtao Hu ◽  
Armistead Russell ◽  
Athanasios Nenes
Keyword(s):  
Significant Influence ◽  
Organic Aerosol ◽  
Liquid Water Content ◽  
Anthropogenic Emissions ◽  
So2 Emissions ◽  
Aerosol Acidity ◽  
A Value ◽  
Future Emission ◽  
The Impact

Formation of aerosol from biogenic hydrocarbons relies heavily on anthropogenic emissions since they control the availability of species such as sulfate and nitrate, and through them, aerosol acidity (pH). To elucidate the role that acidity and emissions play in regulating Secondary Organic Aerosol (SOA), we utilize the 2013 Southern Oxidant and Aerosol Study (SOAS) dataset to enhance the extensive mechanism of isoprene epoxydiol (IEPOX)-mediated SOA formation implemented in the Community Multiscale Air Quality (CMAQ) model (Pye et al., 2013), which was then used to investigate the impact of potential future emission controls on IEPOX OA. We found that the Henry’s law coefficient for IEPOX was the most impactful parameter that controls aqueous isoprene OA products, and a value of 1.9 × 107 M atm−1 provides the best agreement with measurements. Non-volatile cations (NVCs) were found in higher-than-expected quantities in CMAQ and exerted a significant influence on IEPOX OA by reducing its production by as much as 30% when present. Consistent with previous literature, a strong correlation of isoprene OA with sulfate, and little correlation with acidity or liquid water content, was found. Future reductions in SO2 emissions are found to not affect this correlation and generally act to increase the sensitivity of IEPOX OA to sulfate, even in extreme cases.

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