Numerical Modeling

Background and objective: Today, use of models to illustrate the facts and better understanding them, as well as make accurate decisions about phenomena is very common. One of these models is groundwater flow simulation model used by experts in many countries, also, the accuracy and validity of their results has been proved. The object of this study is to evaluate the effect of current management plans of aquifer and Jajrood River basin on changes of the water table of unconfined aquifer and piezometric level of confined aquifer by numerical simulation. Using numerical models, it can be predicted that with the governing process or different management scenarios, how the aquifer reacts to abstraction and recharge.

Materials and methods: In this study, hydraulic behavior of Varamin Plain aquifer was simulated using the Modflow code in GMS software in stable and unstable states. After calibrating the model, hydrodynamic coefficients were corrected, then using the resulted model, quantitative behavior of the aquifer was predicted for two management scenarios in the future years. The first scenario expresses the existing quantitative conditions of the Varamin Aquifer. That is, water do not flow to the plain from southeast wastewater treatment plant of Tehran, but water flows to the Varamin aquifer from Jajrood River. The second scenario indicates situation of the aquifer if the planning are carried out by the relevant organizations. Under this scenario, assigned values from discharging of the southeast wastewater treatment plant of Tehran enter the study area, though due to the implementation of Mamlou storage dam, a significant portion of the surface water resources of Jajrood River will not enter the plain.


Results: According to the maps resulted from the first scenario, decline in groundwater level continues as in previous years, but in the second scenario, considering the utilization of wastewater treatment plant discharge, despite the cutting off the water entering from the Jajrood River to the plain, the groundwater decline rate will decrease, although this decline continues. Comparison of the model implementation under first and second scenarios shows that with the implementation of planned projects, part of the aquifer’s quantitative problems, particularly in the northern areas of the plain, will be decreased, so that in some northern areas the expected decline in groundwater (results of the first scenario) has decreased about 30 to 40 meters by 2041. In the second scenario, a balance of the groundwater is still decreasing, so that storage reduction rate of the aquifer is about 100000000 m3 annually.

Conclusion: Results of the simulation show that under both scenarios (current trend and after implementation of ongoing plans), balance of the groundwater is decreased and decline in water table will be continued, however in comparison to the first scenario, decline rate of water table under the second scenario will be decreased. It can be stated that in order to stop the decline in water level in Varamin aquifer, in addition to water entering plan from Tehran wastewater treatment plant to Varamin plain, recharge of the aquifer from Jajrood River (as the main source of aquifer natural recharge) should be continued.

A geothermal system is basically a system where heat is transferred from the internal part to the surface of The Earth dominantly by conduction, convection, or both. The spatial variation of the magnitude of conductive heat transfer represented by lateral variation of observed surface heat flow values is heavily related to the subsurface temperature distribution, the pattern of which is directly controlled by the variation of rock thermal conductivity values. Therefore, the information about subsurface temperature distribution may provide insight for the interpretation of the thermal structure of a region, within a more regional framework of geothermal systems in particular. In this research, we performed a numerical forward modeling procedure of 2-D conductive heat transfer using finite difference solution of the steady state heat conduction equation via a Gauss-Seidel scheme. The main physical parameters used as the input in the modeling procedure are rock thermal conductivity values as well as temperature boundary conditions. The modeling scheme was applied on two different synthetic common geothermal system geometries, one within a volcanic setting and one within a sedimentary environment, by using appropriate thermal conductivities and temperature boundary conditions for the assumed lithologies within each respective setting. The results of the modeling procedure were able to effectively characterize the thermal structure and surface heat flow patterns of the geothermal system in both environments.

Spatial variability of material properties is inherent in both natural soil deposits and earth structures, yet it is often ignored during geotechnical design. With the objective of developing novel methods for assessing the effects of soil variability on groundwater flow, this study presents a stochastic finite element model of seepage through a flood defense embankment with randomly heterogeneous material properties. Stochastic modeling is undertaken by means of a Monte Carlo simulation which involves a large number of finite element analyses, each with randomly varied porosity at element level, which leads to a corresponding random variation of both permeability and water retention properties across the embankment domain. This provides a statistical distribution of responses, such as total flow rate and time to reach steady state, instead of a single deterministic result as in conventional studies of seepage through unsaturated heterogeneous soils. As the degree of heterogeneity increases, water tends to flow along the most permeable paths inside the soil mass, resulting in an irregular shape of the predicted wetting fronts and pore pressure contours. The mean and standard deviation of the computed quantities strongly depend on the statistics of the input porosity field. Simulations are also conducted to compare the statistical variation of flow rate with and without dependency of the water retention curve on porosity. With recent growth in computer speed, stochastic finite element models based on the Monte Carlo approach can become a powerful design tool, especially if a quantitative assessment of geotechnical risks is required. Copyright © 2011 John Wiley & Sons, Ltd.

Prediction and modeling of hydraulic phenomenon is an important part of hydraulic
engineering activities. One of the applications of prediction and modeling is estimating the
discharge coefficient for hydraulic structures. Side weirs are widely used for allocating and
removing excess flow in water engineering projects. The governing equation on side weir
hydraulic characteristics is spatially varied flow (SVF). Computer modeling of hydraulic
characteristics this structure includes the calculation of water surface profiles and estimating
the discharge coefficient (Cdsw). The numerical method was used to calculate the water surface
profile and there are several ways to estimate the Cdsw, such as experimental formulas and
computational intelligence techniques. In this paper, the Fourth Runge Kutta method is used
for numerical solution of SVF and firstly to estimate Cdsw, some famous empirical equations
are assessed. Among the empirical formulas, the Borghei is the most accurate one. To increase
the accuracy of computer modeling, the Multilayer Neural network (MLP) is developed to
estimate Cdsw. The result shows that using

"Networks are mathematically directed (in practical applications also undirected) graphs and a graph is a one-dimensional abstract complex, i.e., a topological space. Network theory focuses on various topological structures and properties, dynamic properties, and functionality-topology relationship, etc. There are some common mathematical foundations, theories and methodology for network analysis, in which graph theory, statistics, and operational research, etc., are the fundamental sciences of network analysis. Various emerging biological networks, at both micro- and macro- levels, will provide numerous sources for the development of general network theory and methodology and also facilitate the development of theory and methodology of biological networks.

Biological network analysis is a fast moving science. Many core scientific issues, for example, ecological structure, co-evolution, co-extinction and biodiversity conservation in ecology, and cancer development and metabolic regulation in health science, etc., are expected to be addressed by network approaches and network analysis. Network analysis is becoming the core methodology to treat complex biological systems. As the fast development of this area, more and more papers on biological networks are published.

At present explosive numbers of quality papers on biological networks are being published each year. The initiation of the journal, Network Biology, will provide a public and unified platform for the publication of these studies. From this integrated and unique journal, researchers, university teachers and students will thoroughly have an in-depth and complete insight on knowledge, methodology and recent advances of biological networks.

In the view of system dynamics, biological networks are always self-organized systems with emergent, autonomous and adaptive properties. Their dynamics can be represented by agent-based modeling, individual-based modeling and some other methodologies like neural network modeling. Therefore, agent-based modeling, individual-based modeling, self-organization of biological systems, and neural network modeling, etc., fall into the aims and scope of the journal, Network Biology.

The NETWORK BIOLOGY (ISSN 2220-8879) is an open access, peer-reviewed online journal that considers scientific articles in all different areas of network biology. It is the transactions of the International Society of Network Biology.It dedicates to the latest advances in network biology. The goal of this journal is to keep a record of the state-of-the-art research and promote the research work in these fast moving areas. The topics to be covered by Network Biology include, but are not limited to:

•Theories, algorithms and programs of network analysis
•Innovations and applications of biological networks
•Dynamics, optimization and control of biological networks
•Ecological networks, food webs and natural equilibrium
•Co-evolution, co-extinction, biodiversity conservation
•Metabolic networks, protein-protein interaction networks, biochemical reaction networks, gene networks, transcriptional regulatory networks, cell cycle networks, phylogenetic networks, network motifs
•Physiological networks
•Network regulation of metabolic processes, human diseases and ecological systems
•Social networks, epidemiological networks
•System complexity, self-organized systems, emergence of biological systems, agent-based modeling, individual-based modeling, neural network modeling, and other network-based modeling, etc.
We are also interested in short communications that clearly address a specific issue or completely present a new ecological network, food web, or metabolic or gene network, etc.

Authors can submit their works to the email box of this journal, [email protected]. All manuscripts submitted to this journal must be previously unpublished and may not be considered for publication elsewhere at any time during review period of this journal. Authors are asked to read Author Guidelines before submitting manuscripts.

In addition to free submissions from authors around the world, special issues are also accepted. The organizer of a special issue can collect submissions (yielded from a research project, a research group, etc.) on a specific research topic, or submissions of a scientific conference for publication of special issue.

Network Biology 
ISSN 2220-8879
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We introduce FluSI, a fully parallel open source software package for pseudospectral simulations of three-dimensional flapping flight in viscous flows. It is freely available for noncommercial use from GitHub (https://github.com/pseudospectators/FLUSI). The computational framework runs on high performance computers with distributed memory architectures. The discretization of the three-dimensional incompressible Navier-Stokes equations is based on a Fourier pseudospectral method with adaptive time stepping. The complex time varying geometry of insects with rigid flapping wings is handled using the volume penalization method. The modules characterizing the insect geometry, flight mechanics, and wing kinematics are described. Validation tests for different benchmarks illustrate the efficiency and precision of the approach. Finally, computations for a model insect in the turbulent regime demonstrate the versatility of the software.

Bus rapid transit system is modern solution for mass transportation system. The system, in
comparison to the rail-based transportation system, is significantly cheaper and requires shorter development
time, but lower performance. The BRT system performance strongly depends on variables related to station
design and infrastructure. A numerical model offers an effective and efficient means to evaluate the system
performance. This article offers a detailed numerical model on the basis of the discrete-event approach and
demonstrates its application.

Trinidad as a Small Island Developing State (SID) has limited land resources which must be managed against the threat of coastal erosion. Columbus Bay, located on the southwestern
peninsula of the island is negatively affected by high rates of coastal erosion. Erosion in this area has resulted in a reduction in beach amenity, loss of valuable agricultural land, critical
mangrove habitats and damage to infrastructure. Although the erosion problem is well documented, the challenges lie in management due to the limited understanding of the interaction of coastal processes and sediment transport in the area. While other studies have identified the existence and causal link between coastal erosion and tidal currents in macro-tidal environments, this study examines the interaction of tides on coastal processes and sediment transport in a micro-tidal setting. The study combines traditional field and levelling techniques alongside numerical modelling on data from 2009-2013. It utilizes the Spectral Wave (SW), Hydrodynamic (HD) and Sediment Transport (ST) modules of MIKE 21.

EPBs and slurry machines are commonly used in urban tunnelling projects, since they decrease the displacements induced by tunnel excavation, ensuring high performance in a wide range of ground conditions, low cover depths and high ground water pressures. The calculations related with mechanized tunnelling (settlements, dimensioning of the tunnel lining etc.) are usually carried out by using simplified approaches, such as 2D numerical analyses, empirical methods etc. However, the simulation of the actual construction procedure includes high complexity due to the multiple interfaces, the role of the 3D geometry, the different phases of the grout and the structural system of the segmental lining (radial and longitudinal joints). This paper presents a realistic full 3D simulation of a shield tunnelling process (EPB or slurry machine) with the finite element code ABAQUS. The objective of this paper is to demonstrate the main modeling techniques employed for the simulation of several key characteristics of the excavation and construction. Indicatively, the main components of the machine (shield, excavation chamber, cutterhead) are simulated using solid elements and the gaps due to overcut and tapered shield are also included in the model via interface elements. The tail void grout is modeled with 3-dimensional finite elements simulating in detail the grout injection pressure and the time-dependent hardening. The segmental lining is modeled with shell elements, considering the coupling behaviour of the joints between the segments, resulting to a more realistic distribution of the internal forces and consequently the dimensioning of the concrete shell.