Experiments on vertical transverse mixing in a large-scale heterogeneous model aquifer

2005 ◽  
Vol 80 (3-4) ◽  
pp. 130-148 ◽  
Author(s):  
Md. Arifur Rahman ◽  
Surabhin C. Jose ◽  
Wolfgang Nowak ◽  
Olaf A. Cirpka
Parasitology ◽  
2004 ◽  
Vol 130 (1) ◽  
pp. 49-65 ◽  
Author(s):  
D. GURARIE ◽  
C. H. KING

Prior field studies and modelling analyses have individually highlighted the importance of age-specific and spatial heterogeneities on the risk for schistosomiasis in human populations. As long-term, large-scale drug treatment programs for schistosomiasis are initiated in subSaharan Africa and elsewhere, optimal strategies for timing and distribution of therapy have yet to be fully defined on the working, district-level scale, where strong heterogeneities are often observed among sublocations. Based on transmission estimates from recent field studies, we develop an extended model of heterogeneous schistosome transmission for distributed human and snail population clusters and age-dependent behaviour, based on a ‘mean worm burden+snail infection prevalence’ formulation. We analyse its equilibria and basic reproduction patterns and their dependence on the underlying transmission parameters. Our model allows the exploration of chemotherapy-based control strategies targeted at high-risk behavioural groups and localities, and the approach to an optimal design in terms of cost. Efficacy of the approach is demonstrated for a model environment having linked, but spatially-distributed, populations and transmission sites.


2004 ◽  
Vol 854 ◽  
Author(s):  
Youhong Li ◽  
Yinon Ashkenazy ◽  
Robert S. Averback

ABSTRACTLarge-scale Molecular Dynamics (MD) studies on heterogeneous, model metal systems subjected to intense shock loading by a flyer plate were carried out. Of interest here is the effect of structural defects on interfacial strength under these extreme conditions. The metal target and flyer were essentially single crystals of Cu, but an interface layer was created by varying the mass of the Cu atoms in part of the sample. Interfacial defects in the form of vacancies, and at different concentrations, were introduced into the interfacial region. In addition to microstructural evolution of damage in this system, the shock induced temperature and pressure changes were also analyzed.


Author(s):  
Sumit K. Majumdar

This chapter describes the evolution of India’s industrial structure. Unlike industrialization carried out through large state-owned firms, or industrialization through a cadre of large private corporations, or industrialization through a network of small firms, many alternative organizational dynamics play simultaneously in the Indian system. The system consists of many private businesses that constitute the large-scale industrial sector. Policies were put in place to develop the molecular economy and to develop State-owned firms investing in large-scale units. These policies led to the emergence of important and dynamic segments making up India’s heterogeneous model of capitalism. Each has been in coexistence with the other and added variety to the economy. In the quest for economic progress, if Indian society was to be industrialized, modernized, autonomous, self-reliant, able to defend itself, and an independent center of economic power, State-directed industrialization was realized as a key solution for national development.


2019 ◽  
Vol 20 (5) ◽  
pp. 1072 ◽  
Author(s):  
Yuyu Wang ◽  
Xiaofan Zhou ◽  
Liming Wang ◽  
Xingyue Liu ◽  
Ding Yang ◽  
...  

Neuropterida is a super order of Holometabola that consists of the orders Megaloptera (dobsonflies, fishflies, and alderflies), Neuroptera (lacewings) and Raphidioptera (snakeflies). Several proposed higher-level relationships within Neuropterida, such as the relationships between the orders or between the families, have been extensively debated. To further understand the evolutionary history of Neuropterida, we conducted phylogenomic analyses of all 13 published transcriptomes of the neuropterid species, as well as of a new transcriptome of the fishfly species Ctenochauliodes similis of Liu and Yang, 2006 (Megaloptera: Corydalidae: Chauliodinae) that we sequenced. Our phylogenomic data matrix contained 1392 ortholog genes from 22 holometabolan species representing six families from Neuroptera, two families from Raphidioptera, and two families from Megaloptera as the ingroup taxa, and nine orders of Holometabola as outgroups. Phylogenetic reconstruction was performed using both concatenation and coalescent-based approaches under a site-homogeneous model as well as under a site-heterogeneous model. Surprisingly, analyses using the site-homogeneous model strongly supported a paraphyletic Neuroptera, with Coniopterygidae assigned as the sister group of all other Neuropterida. In contrast, analyses using the site-heterogeneous model recovered Neuroptera as monophyletic. The monophyly of Neuroptera was also recovered in concatenation and coalescent-based analyses using genes with stronger phylogenetic signals [i.e., higher average bootstrap support (ABS) values and higher relative tree certainty including all conflicting bipartitions (RTCA) values] under the site-homogeneous model. The present study illustrated how both data selection and model selection influence phylogenomic analyses of large-scale data matrices comprehensively.


2013 ◽  
Vol 284-287 ◽  
pp. 1468-1472 ◽  
Author(s):  
Chien Hao Tseng ◽  
Chia Chen Kuo ◽  
Wei Chih Su ◽  
Chuan Lin Lai

Carbon-Dioxide Capture and Storage (CCS) in deep saline aquifers is one of the most feasible techniques for reducing anthropogenic emission of carbon dioxide (CO2). In this paper, a high-performance parallel computing is used to simulate the large-scale and long-term CO2 geologic storage in the saline aquifer (Sleipner Vest field in the Norwegian) based on the ECO2N module of the flow/transport simulator TOUGH2-MP, which is the parallel version of TOUGH2 implemented by the MPI. We have developed a complex three-dimensional heterogeneous model to study the spatial and temporal distribution and storage of CO2 injection into the sands of the Utsira formation, at the Sleipner Vest field in the Norway. Simulation results demonstrate that the high-speed parallel computing enhanced the capability on handling the large-scale model and the long-term studies. Furthermore, in order to avoid the problems of overpressure in the saline reservoir, the case study employs multi-well (ten-well) injection model, which has been proven to be able to reduce the reservoir pressure effectively when compared to the single-well injection model.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lin Fu ◽  
Yaqing Ding

As an important carrier of human production, life, and social development, the emergence of cities symbolizes the maturity and civilization of mankind. For more than 40 years of reform and opening up, our country’s economic development has become increasingly prosperous, and urbanization is booming. At present, our country is in a decisive period for building a well-off society in an all-round way, with rapid progress in socio-economic growth and urbanization. Based on this, this article is oriented towards urban visualization modeling work and proposes a cluster modeling method that is compatible with the combination of urban geological structure and three-dimensional urban space, so that urban space modeling work not only pays attention to the rationality of above-ground planning and construction but also fully considers underground geology the stability and safety of the structure. This paper uses the 3D city online visualization modeling technology to efficiently and reasonably complete the 3D urban geological modeling under the fusion of multiple geological data and combines the organic combination of multisource heterogeneous model data to convert the geological model data into a 3D geographic information model; the universal standard format analyzes the rapid construction of large-scale complex geological structure models and the integrated expression of multisource heterogeneous model data. Experiments have proved that from the cluster capacity of 5,000 to 100,000, no matter how much the modeling time is different, whether it is to search the entire territory or part of the scope, the search time of the 3D city visualization model is less than 20 ms, and the 3D city visualization model map of the city can be well established. This shows that the three-dimensional city visualization model highlights the impact of the urban geological environment on urban construction and development and visually and vividly displays region geological structure and other information in a three-dimensional way, providing corresponding information for urban geological stability assessment and geological disaster rescue reference and help.


1980 ◽  
Vol 101 (1) ◽  
pp. 201-221 ◽  
Author(s):  
M. R. Davis ◽  
H. Winarto

The decay of a jet discharging from a circular nozzle parallel to and displaced from a solid surface is investigated under conditions where the transitional process from circular-jet flow to oblate wall-jet flow begins in the initial, transition or self-preserving regions of the original jet. The influence of displacement of the nozzle from the plane on the developed three-dimensional wall jet downstream is demonstrated and it is found that the transitional interaction with the plane is more extended when the plane interacts first in the initial zone of the circular jet. Measurements of turbulence and Reynolds stress show the transverse mixing parallel to the plane to exceed that perpendicular to the plane, and are generally consistent with the spreading rates in these two directions, the ratio of which approaches 8·5 at large distances from the nozzle. It is shown that the interaction between the plane and jet involves a relatively large-scale coherent motion in which components of velocity directed towards or away from the surface are associated with outflow or inflow along the surface. This motion is more extended in the direction parallel to the surface and provides a mechanism for the increases in mixing rate in the direction parallel to the plane.


1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.


1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.


Sign in / Sign up

Export Citation Format

Share Document